@article {6200, title = {Clarifying the effect of biodiversity on productivity in natural ecosystems with longitudinal data and new methods for causal inference}, journal = {Nature Communications}, year = {In Press}, keywords = {LTER-KNZ}, author = {Dee, L.E. and Ferraro, P.J. and Severen, C. and Kimmel, K. and Borer, E.T. and Byrnes, J.E.K. and Clark, A. and Hautier, Y. and Hector, A. and Raynaud, X. and Reich, P.B. and Wright, A. and Arnillas, C.A. and Davies, K.F. and MacDougall, A.S. and Mori, A. and Smith, M.D. and Adler, P.B. and Bakker, J.D. and Braumann, K. and Cowles, J.M. and Komatsu, K.J. and Knops, J. and McCulley, R. and Moore, J.L. and Morgan, J.W. and Ohlert, T. and Power, S.A. and Sullivan, L. and Stevens, C. and Loreau, M.} } @article {6266, title = {Nothing lasts forever: Dominant species decline under rapid environmental change in global grasslandsAbstract}, journal = {Journal of Ecology}, year = {In Press}, keywords = {LTER-KNZ}, doi = {10.1111/1365-2745.14198}, url = {https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2745.14198}, author = {Wilfahrt, Peter A. and Seabloom, Eric W. and Bakker, Jonathan D. and Biederman, Lori and Bugalho, Miguel N. and Cadotte, Marc W. and Caldeira, Maria C. and Catford, Jane A. and Chen, Qingqing and Donohue, Ian and Ebeling, Anne and Eisenhauer, Nico and Haider, Sylvia and Heckman, Robert W. and Jentsch, Anke and Koerner, S.E. and Komatsu, K.J. and Laungani, Ramesh and MacDougall, Andrew and Martina, Jason P. and Martinson, Holly and Moore, Joslin L. and Niu, Yujie and Ohlert, Timothy and Venterink, Harry Olde and Orr, Devyn and Peri, Pablo and Pos, Edwin and Price, Jodi and Raynaud, Xavier and Ren, Zhengwei and Roscher, Christiane and Smith, Nicholas G. and Stevens, Carly J. and Sullivan, Lauren L. and Tedder, Michelle and Tognetti, Pedro M. and Veen, Ciska and Wheeler, George and Young, Alyssa L. and Young, Hillary and Borer, Elizabeth T.} } @article {6303, title = {Plant responses to changing rainfall frequency and magnitude}, journal = {Nature Ecology \& Evolution}, year = {In Press}, keywords = {LTER-KNZ}, author = {Feldman, A.F. and Feng, X. and Felton, A.J. and Konings, A.G. and Knapp, A.K. and Biederman, A.J. and Poulter, B.} } @article {6277, title = {Pleoardoris graminearum gen. et sp. nov., a new member of Pleosporales from the North American Plains, biogeography and effects on B. gracilis growth}, journal = {Mycologia}, year = {In Press}, keywords = {LTER-KNZ}, author = {Pinchi-Davila, X. and Vargas-Hernandez, D. and Romero-Jimenez, M. and Jumpponen, A. and Rudgers, J. and Herrera, J. and Hutchinson, M. and Dunbar, J.M. and Kuske, C. and Porras-Alfaro, A.} } @article {6107, title = {Removing a perched culvert facilitates dispersal of fishes in an intermittent prairie stream but not recovery from drought}, journal = {Freshwater Science}, year = {In Press}, keywords = {LTER-KNZ}, author = {K. B. Gido and Hedden, S.C. and Bruckerhoff, Lindsey A and Pennock, C.A. and Hedden, Crosby K. and Hopper, Garrett W. and Renner, E.A. and Johnson, E.R. and Postlethwait, B.J.} } @article {6291, title = {Changes in water age during dry-down of a non-perennial stream}, journal = {Water Resources Research}, volume = {60}, year = {2024}, pages = {e2023WR034623}, keywords = {LTER-KNZ}, doi = {10.1029/2023WR034623}, url = {https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023WR034623}, author = {Swenson, Logan J. and Zipper, Sam and Peterson, Delaney M. and Jones, C. Nathan and Burgin, Amy J. and Seybold, Erin and Kirk, Matthew F. and Hatley, Camden} } @article {6294, title = {Extreme drought impacts have been underestimated in grasslands and shrublands globally}, journal = {Proceedings of the National Academy of Sciences}, volume = {121}, year = {2024}, pages = {e230988112}, keywords = {LTER-KNZ}, doi = {10.1073/pnas.2309881120}, url = {https://pnas.org/doi/10.1073/pnas.2309881120}, author = {M. D. Smith and Wilkins, Kate D. and Holdrege, Martin C. and Wilfahrt, Peter and S.L Collins and Knapp, Alan K. and Sala, Osvaldo E. and Dukes, Jeffrey S. and Phillips, Richard P. and Yahdjian, Laura and Gherardi, Laureano A. and Ohlert, Timothy and Beier, Claus and Fraser, Lauchlan H. and Jentsch, Anke and Loik, Michael E. and Maestre, Fernando T. and Power, Sally A. and Yu, Qiang and Felton, Andrew J. and Munson, Seth M. and Luo, Yiqi and Abdoli, Hamed and Abedi, Mehdi and Alados, Concepci{\'o}n L. and Alberti, Juan and Alon, Moshe and An, Hui and Anacker, Brian and Anderson, Maggie and Auge, Harald and Bachle, Seton and Bahalkeh, Khadijeh and Bahn, Michael and Batbaatar, Amgaa and Bauerle, Taryn and Beard, Karen H. and Behn, Kai and Beil, Ilka and Biancari, Lucio and Blindow, Irmgard and Bondaruk, Viviana Florencia and Borer, Elizabeth T. and Bork, Edward W. and Bruschetti, Carlos Martin and Byrne, Kerry M. and Cahill Jr., James F. and Calvo, Dianela A. and Carbognani, Michele and Cardoni, Augusto and Carlyle, Cameron N. and Castillo-Garcia, Miguel and Chang, Scott X. and Chieppa, Jeff and Cianciaruso, Marcus V. and Cohen, Ofer and Cordeiro, Amanda L. and Cusack, Daniela F. and Dahlke, Sven and Daleo, Pedro and D{\textquoteright}Antonio, Carla M. and Dietterich, Lee H. and S. Doherty, Tim and Dubbert, Maren and Ebeling, Anne and Eisenhauer, Nico and Fischer, Fel{\'\i}cia M. and Forte, T{\textquoteright}ai G. W. and Gebauer, Tobias and Gozalo, Beatriz and Greenville, Aaron C. and Guidoni-Martins, Karlo G. and Hannusch, Heather J. and Vats{\o} Haugum, Siri and Hautier, Yann and Hefting, Mariet and Henry, Hugh A. L. and Hoss, Daniela and Ingrisch, Johannes and Iribarne, Oscar and Isbell, Forest and Johnson, Yari and Jordan, Samuel and Kelly, Eugene F. and Kimmel, Kaitlin and Kreyling, Juergen and Kr{\"o}el-Dulay, Gy{\"o}rgy and Kr{\"o}pfl, Alicia and K{\"u}bert, Angelika and Kulmatiski, Andrew and Lamb, Eric G. and Larsen, Klaus Steenberg and Larson, Julie and Lawson, Jason and Leder, Cintia V. and Linst{\"a}dter, Anja and Liu, Jielin and Liu, Shirong and Lodge, Alexandra G. and Longo, Grisel and Loydi, Alejandro and Luan, Junwei and Curtis Lubbe, Frederick and Macfarlane, Craig and Mackie-Haas, Kathleen and Malyshev, Andrey V. and Maturano-Ruiz, {\'a}n and Merchant, Thomas and Metcalfe, Daniel B. and Mori, Akira S. and Mudongo, Edwin and Newman, Gregory S. and Nielsen, Uffe N. and Nimmo, Dale and Niu, Yujie and Nobre, Paola and O{\textquoteright}Connor, Rory C. and Ogaya, Rom{\`a} and O{\~n}atibia, Gast{\'o}n R. and Orb{\'a}n, Ildik{\'o} and Osborne, Brooke and Otfinowski, Rafael and P{\"a}rtel, Meelis and Pe{\~n}uelas, Josep and Peri, Pablo L. and Peter, Guadalupe and Petraglia, Alessandro and Picon-Cochard, Catherine and Pillar, Val{\'e}rio D. and Pi{\~N}Eiro-Guerra, Juan Manuel and Ploughe, Laura W. and Plowes, Robert M. and Portales-Reyes, Cristy and Prober, Suzanne M. and Pueyo, Yolanda and Reed, Sasha C. and Ritchie, Euan G. and Rodr{\'\i}guez, Ayl{\'e}n and Rogers, William E. and Roscher, Christiane and S{\'a}nchez, Ana M. and Santos, Br{\'a}ulio A. and Scarf{\'o}, Mar{\'\i}a and Seabloom, Eric W. and Shi, Baoku and Souza, Lara and Stampfli, Andreas and Standish, Rachel J. and Sternberg, Marcelo and Sun, Wei and S{\"u}nnemann, Marie and Tedder, Michelle and Thorvaldsen, {\r a}l and Tian, Dashuan and Tielb{\"o}rger, Katja and Valdecantos, Alejandro and van den Brink, Liesbeth and Vandvik, Vigdis and Vankoughnett, Mathew R. and Guri Velle, Liv and Wang, Changhui and Wang, Yi and Wardle, Glenda M. and Werner, Christiane and Wei, Cunzheng and Wiehl, Georg and Williams, Jennifer L. and Wolf, Amelia A. and Zeiter, Michaela and Zhang, Fawei and Zhu, Juntao and Zong, Ning and Zuo, Xiaoan} } @article {6298, title = {Accounting for herbaceous communities in process-based models will advance our understanding of {\textquotedblleft}grassy{\textquotedblright} ecosystems}, journal = {Global Change Biology}, volume = {29}, year = {2023}, pages = {6453 - 6477}, keywords = {LTER-KNZ}, issn = {1354-1013}, doi = {10.1111/gcb.v29.2310.1111/gcb.16950}, url = {https://onlinelibrary.wiley.com/doi/10.1111/gcb.16950}, author = {K.R. Wilcox and Chen, Anping and M.L. Avolio and Butler, Ethan E. and S.L Collins and Fisher, Rosie and Keenan, Trevor and Kiang, Nancy Y. and Alan K. Knapp and Koerner, S.E. and Kueppers, Lara and Liang, Guopeng and Lieungh, Eva and Loik, Michael and Luo, Yiqi and Poulter, Ben and Reich, Peter and Renwick, Katherine and M. D. Smith and Walker, Anthony and Weng, Ensheng and Komatsu, K.J.} } @article {6299, title = {Assessing carbon storage capacity and saturation across six central US grasslands using data{\textendash}model integration}, journal = {Biogeosciences}, volume = {20}, year = {2023}, pages = {2707 - 2725}, keywords = {LTER-KNZ}, doi = {10.5194/bg-20-2707-2023}, url = {https://bg.copernicus.org/articles/20/2707/2023/}, author = {K.R. Wilcox and S.L Collins and Alan K. Knapp and Pockman, William and Shi, Zheng and M. D. Smith and Luo, Yiqi} } @article {6238, title = {Compositional variation in grassland plant communities}, journal = {Ecosphere}, volume = {14}, year = {2023}, pages = {e4542}, keywords = {LTER-KNZ}, doi = {10.1002/ecs2.v14.610.1002/ecs2.4542}, url = {https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecs2.4542}, author = {Bakker, Jonathan D. and Price, Jodi N. and Henning, Jeremiah A. and Batzer, Evan E. and Ohlert, Timothy J. and Wainwright, Claire E. and Adler, Peter B. and Alberti, Juan and Arnillas, Carlos Alberto and Biederman, Lori A. and Borer, Elizabeth T. and Brudvig, Lars A. and Buckley, Yvonne M. and Bugalho, Miguel N. and Cadotte, Marc W. and Caldeira, Maria C. and Catford, Jane A. and Chen, Qingqing and Crawley, Michael J. and Daleo, Pedro and Dickman, Chris R. and Donohue, Ian and DuPre, Mary Ellyn and Ebeling, Anne and Eisenhauer, Nico and Fay, Philip A. and Gruner, Daniel S. and Haider, Sylvia and Hautier, Yann and Jentsch, Anke and Kirkman, Kevin and Knops, Johannes M. H. and Lannes, Lu{\'\i}ola S. and MacDougall, Andrew S. and McCulley, Rebecca L. and Mitchell, Rachel M. and Moore, Joslin L. and Morgan, John W. and Mortensen, Brent and Olde Venterink, Harry and Peri, Pablo L. and Power, Sally A. and Prober, Suzanne M. and Roscher, Christiane and Sankaran, Mahesh and Seabloom, Eric W. and M. D. Smith and Stevens, Carly and Sullivan, Lauren L. and Tedder, Michelle and Veen, G. F. (Ciska) and Virtanen, Risto and Wardle, Glenda M.} } @article {6145, title = {Nutrient addition drives declines in grassland species richness primarily via enhanced species loss}, journal = {Journal of Ecology}, volume = {111}, year = {2023}, pages = {552-563}, keywords = {LTER-KNZ}, doi = {10.1111/1365-2745.14038}, url = {https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2745.14038}, author = {Muehleisen, Andrew J. and Watkins, Carmen R. E. and Altmire, Gabriella R. and Shaw, E. Ashley and Case, Madelon F. and Aoyama, Lina and Brambila, Alejandro and Reed, Paul B. and LaForgia, Marina and Borer, Elizabeth T. and Seabloom, Eric W. and Bakker, Jonathan D. and Amillas, Carlos Alberto and Biederman, Lori and Chen, Qingqing and Cleland, Elsa E. and Fay, Philip A. and Hagenah, Nicole and Harpole, Stan and Hautier, Yann and Henning, Jeremiah A. and Knops, Johannes M. H. and Kimberly J. Komatsu and Ladouceur, Emma and MacDougall, Andrew and McCulley, Rebecca L. and Moore, Joslin L. and Ohlert, Tim and Power, Sally A. and Stevens, Carly J. and Wilfahrt, Peter and Hallett, Lauren M.} } @article {6204, title = {Remotely sensed soil moisture can capture dynamics relevant to plant water uptake}, journal = {Water Resources Research}, volume = {59}, year = {2023}, pages = {e2022WR033814}, keywords = {LTER-KNZ}, doi = {10.1029/2022WR033814}, url = {https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022WR033814}, author = {Feldman, Andrew F. and Short Gianotti, Daniel J. and Dong, Jianzhi and Akbar, Ruzbeh and Crow, Wade T. and McColl, Kaighin A. and Konings, Alexandra G. and Nippert, J.B. and Tumber-D{\'a}vila, Shersingh Joseph and Holbrook, Noel M. and Rockwell, Fulton E. and Scott, Russell L. and Reichle, Rolf H. and Chatterjee, Abhishek and Joiner, Joanna and Poulter, Benjamin and Entekhabi, Dara} } @article {6000, title = {Biogeography of root-associated fungi in foundation grasses of North American plains}, journal = {Biogeography}, volume = {49}, year = {2022}, pages = {22-37}, keywords = {LTER-KNZ}, doi = {10.1111/jbi.14260}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/jbi.14260}, author = {Rudgers, J.A. and Fox, S. and Porras-Alfaro, A. and Herrera, J. and Reazin, C. and Kent, D.R. and Souza, L. and Chung, Y.A. and Jumpponen, A.} } @article {6128, title = { Cross-site comparisons of climate change on drylands in the US Long-term Ecological Research network}, journal = {BioScience}, volume = {72}, year = {2022}, pages = {889 - 907}, keywords = {LTER-KNZ}, doi = {10.1093/biosci/biab134}, url = {https://academic.oup.com/bioscience/article/72/9/889/6654840}, author = {Hudson, Amy R and Peters, D.P.C. and J. M. Blair and Childers, Daniel L and Doran, Peter T and Geil, Kerrie and Gooseff, Michael and Gross, Katherine L and Haddad, Nick M and Pastore, Melissa A and Rudgers, Jennifer A and Sala, Osvaldo and Seabloom, Eric W and Shaver, Gaius} } @article {6274, title = {Darksidea phi, sp. nov., a dark septate root-associated fungus in foundation grasses in North American Great Plains}, journal = {Mycologia}, volume = {11420164110338}, year = {2022}, pages = {254-269}, keywords = {LTER-KNZ}, issn = {0027-5514}, doi = {10.1080/00275514.2022.2031780}, url = {https://www.tandfonline.com/doi/full/10.1080/00275514.2022.2031780}, author = {Romero-Jim{\'e}neza, Mar{\'\i}a-Jos{\'e}. and Rudgers, Jennifer A. and Jumpponen, Ari and Herrera, Jose and Hutchinson, Miriam and Kuske, Cheryl and Dunbar, John and Knapp, D{\'a}niel G. and Kov{\'a}cs, G{\'a}bor M. and Porras-Alfaro, Andrea} } @article {6083, title = {Kernel weight contribution to yield genetic gain of maize: a global review and US case studies}, journal = {Journal of Experimental Botany}, volume = {73}, year = {2022}, pages = {3597 - 3609}, keywords = {LTER-KNZ}, doi = {10.1093/jxb/erac103}, url = {https://academic.oup.com/jxb/article/73/11/3597/6547901}, author = {Fern{\'a}ndez, Javier A and Messina, Carlos D and Salinas, Andrea and Prasad, P V Vara and Jesse B. Nippert and Ciampitti, Ignacio A}, editor = {Dreisigacker, Susanne} } @article {6133, title = {Linking changes in species composition and biomass in a globally distributed grassland experiment}, journal = {Ecology Letters}, volume = {25}, year = {2022}, pages = {2699-2712}, keywords = {LTER-KNZ}, doi = {10.1111/ele.14126}, url = {https://onlinelibrary.wiley.com/doi/10.1111/ele.14126}, author = {Ladouceur, Emma and Blowes, Shane A. and Chase, Jonathan M. and Clark, Adam T. and Garbowski, Magda and Alberti, Juan and Arnillas, Carlos Alberto and Bakker, Jonathan D. and Barrio, Isabel C. and Bharath, Siddharth and Borer, Elizabeth T. and Brudvig, Lars A. and Cadotte, Marc W. and Chen, Qingqing and Collins, Scott L. and Dickman, Christopher R. and Donohue, Ian and Du, Guozhen and Ebeling, Anne and Eisenhauer, Nico and Fay, Philip A. and Hagenah, Nicole and Hautier, Yann and Jentsch, Anke and J{\'o}nsd{\'o}ttir, Ingibj{\"o}rg S. and Kimberly J. Komatsu and MacDougall, Andrew and Martina, Jason P. and Moore, Joslin L. and Morgan, John W. and Peri, Pablo L. and Power, ~A. and Ren, Zhengwei and Risch, Anita C. and Roscher, Christiane and Schuchardt, ~A. and Seabloom, Eric W. and Stevens, Carly J. and Veen, G.F. (Ciska) and Virtanen, Risto and Wardle, Glenda M. and Wilfahrt, Peter A. and Harpole, W. Stanley} } @article {6050, title = {N and P constrain C in ecosystems under climate change: role of nutrient redistribution, accumulation, and stoichiometry}, journal = {Ecological Applications}, volume = {32}, year = {2022}, pages = {e2684}, keywords = {LTER-KNZ}, doi = {10.1002/eap.2684}, url = {https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/eap.2684}, author = {Rastetter, E.B. and Kwiakowski, B.L. and Kicklighter, D.W. and Barker Plotkin, A. and Genet, H. and Jesse B. Nippert and O{\textquoteright}Keefe, K. and Perakis, S.R. and Porder, S. and Roley, S.S. and Reuss, R.W. and Thompson, J.R. and Wieder, W.R. and K.R. Wilcox and Yanai, R.D.} } @article {6112, title = {Nutrient enrichment increases invertebrate herbivory and pathogen damage in grasslands}, journal = {Journal of Ecology}, volume = {110}, year = {2022}, pages = {327 - 339}, keywords = {LTER-KNZ}, doi = {10.1111/1365-2745.13801}, url = {https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2745.13801}, author = {Ebeling, Anne and Strauss, Alex T. and Adler, Peter B. and Arnillas, Carlos A. and Barrio, ~C. and Biederman, Lori A. and Borer, Elizabeth T. and Bugalho, Miguel N. and Caldeira, ~C. and Cadotte, Marc W. and Daleo, Pedro and Eisenhauer, Nico and Eskelinen, Anu and Fay, Philip A. and Firn, Jennifer and Graff, Pamela and Hagenah, Nicole and Haider, Sylvia and Kimberly J. Komatsu and McCulley, ~L. and Mitchell, Charles E. and Moore, Joslin L. and Pascual, Jesus and Peri, Pablo L. and Power, Sally A. and Prober, Suzanne M. and Risch, ~C. and Roscher, Christiane and Sankaran, Mahesh and Seabloom, ~W. and Schielzeth, Holger and Sch{\"u}tz, Martin and Speziale, Karina L. and Tedder, Michelle and Virtanen, Risto and Blumenthal, Dana M.} } @article {6110, title = {Nutrient identity modifies the destabilising effects of eutrophication in grasslands}, journal = {Ecology Letters}, volume = {259}, year = {2022}, pages = {754 - 765}, abstract = {

Nutrient enrichment can simultaneously increase and destabilise plant biomass production, with co-limitation by multiple nutrients potentially intensifying these effects. Here, we test how factorial additions of nitrogen (N), phosphorus (P) and potassium with essential nutrients (K+) affect the stability (mean/standard deviation) of aboveground biomass in 34 grasslands over 7 years. Destabilisation with fertilisation was prevalent but was driven by single nutrients, not synergistic nutrient interactions. On average, N-based treatments increased mean biomass production by 21\–51\% but increased its standard deviation by 40\–68\% and so consistently reduced stability. Adding P increased interannual variability and reduced stability without altering mean biomass, while K+ had no general effects. Declines in stability were largest in the most nutrient-limited grasslands, or where nutrients reduced species richness or intensified species synchrony. We show that nutrients can differentially impact the stability of biomass production, with N and P in particular disproportionately increasing its interannual variability.

}, keywords = {LTER-KNZ}, issn = {1461-023X}, doi = {10.1111/ele.v25.410.1111/ele.13946}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/ele.13946}, author = {Carroll, Oliver and Batzer, Evan and Bharath, Siddharth and Borer, Elizabeth T. and Campana, {\'\i}a and Esch, Ellen and Hautier, Yann and Ohlert, Timothy and Seabloom, Eric W. and Adler, Peter B. and Bakker, Jonathan D. and Biederman, Lori and Bugalho, Miguel N. and Caldeira, Maria and Chen, Qingqing and Davies, Kendi F. and Fay, Philip A. and Knops, Johannes M. H. and Kimberly J. Komatsu and Martina, Jason P. and McCann, Kevin S. and Moore, Joslin L. and Morgan, John W. and Muraina, Taofeek O. and Osborne, Brooke and Risch, Anita C. and Stevens, Carly and Wilfahrt, Peter A. and Yahdjian, Laura and MacDougall, Andrew S.}, editor = {Pe{\~n}uelas, Josep} } @article {6109, title = {Nutrients and herbivores impact grassland stability across spatial scales through different pathways}, journal = {28}, volume = {8}, year = {2022}, pages = {2678-2688}, abstract = {

Nutrients and herbivores are well-known drivers of grassland diversity and stability in local communities. However, whether they interact to impact the stability of aboveground biomass and whether these effects depend on spatial scales remain unknown. It is also unclear whether nutrients and herbivores impact stability via different facets of plant diversity including species richness, evenness, and changes in community composition through time and space. We used a replicated experiment adding nutrients and excluding herbivores for 5 years in 34 global grasslands to explore these questions. We found that both nutrient addition and herbivore exclusion alone reduced stability at the larger spatial scale (aggregated local communities; gamma stability), but through different pathways. Nutrient addition reduced gamma stability primarily by increasing changes in local community composition over time, which was mainly driven by species replacement. Herbivore exclusion reduced gamma stability primarily by decreasing asynchronous dynamics among local communities (spatial asynchrony). Their interaction weakly increased gamma stability by increasing spatial asynchrony. Our findings indicate that disentangling the processes operating at different spatial scales may improve conservation and management aiming at maintaining the ability of ecosystems to reliably provide functions and services for humanity.

}, keywords = {LTER-KNZ}, doi = {10.1111/gcb.16086}, url = {https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.16086}, author = {Chen, Qingqing and Wang, Shaopeng and Seabloom, E.W. and MacDougall, A.S. and Borer, E.T. and Bakker, Jonathan D. and Donohue, Ian. and Knops, J.M.H. and Morgan, J.W. and Carroll, Oliver. and Crawley, M. and Bugalho, M.N. and Power, S.A. and Eskelinen, A. and Virtanen, R.} } @article {6207, title = {Partitioning evapotranspiration in a tallgrass prairie using micrometeorological and water use efficiency approaches under contrasting rainfall regimes}, journal = {Journal of Hydrology}, volume = {608}, year = {2022}, pages = {127624}, keywords = {LTER-KNZ}, doi = {10.1016/j.jhydrol.2022.127624}, url = {https://www.sciencedirect.com/science/article/abs/pii/S0022169422001998?via\%3Dihub$\#$preview-section-references}, author = {da Rocha, Adolpho Emanuel Quintela and Santos, Eduardo Alvarez and Patrignani, Andres} } @article {6052, title = {Poor relationships between NEON Airborne Observation Platform data and field-based vegetation traits at a mesic grassland}, journal = {Ecology}, volume = {103}, year = {2022}, pages = {e03590}, keywords = {LTER-KNZ}, doi = {10.1002/ecy.v103.210.1002/ecy.3590}, url = {https://onlinelibrary.wiley.com/toc/19399170/103/2}, author = {Pau, Stephanie and Jesse B. Nippert and Slapikas, Ryan and Griffith, D. and Bachle, Seton and Helliker, Brent R. and O{\textquoteright}Connor, R.C. and Riley, William J. and Still, Christopher J. and Zaricor, Marissa} } @article {6086, title = {Post-silking 15N labelling reveals an enhanced nitrogen allocation to leaves in modern maize (Zea mays) genotypes}, journal = {Journal of Plant Physiology}, volume = {268}, year = {2022}, pages = {153577}, keywords = {LTER-KNZ}, doi = {10.1016/j.jplph.2021.153577}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0176161721002169}, author = {Fernandez, Javier A. and Jesse B. Nippert and Prasad, P.V. Vara and Messina, Carlos D. and Ciampitti, Ignacio A.} } @article {6069, title = {Precipitation, not land use, primarily determines the composition of both plant and phyllosphere fungal communities}, journal = {Frontiers in Fungal Biology}, volume = {3}, year = {2022}, pages = {805225}, keywords = {LTER-KNZ}, doi = {10.3389/ffunb.2022.805225}, url = {https://www.frontiersin.org/articles/10.3389/ffunb.2022.805225/full}, author = {Dea, Hannah I. and Urban, Abigail and Kazarina, Anna and Houseman, Gregory R. and Thomas, Samantha G. and Loecke, Terry and Greer, Mitchell J. and Platt, Thomas G. and Lee, Sonny and A. Jumpponen} } @article {6108, title = {Simple statistical models can be sufficient for testing hypotheses with population time-series data}, journal = {Ecology and Evolution}, volume = {12}, year = {2022}, pages = {e9339}, abstract = {

Time-series data offer wide-ranging opportunities to test hypotheses about the physical and biological factors that influence species abundances. Although sophisticated models have been developed and applied to analyze abundance time series, they require information about species detectability that is often unavailable. We propose that in many cases, simpler models are adequate for testing hypotheses. We consider three relatively simple regression models for time series, using simulated and empirical (fish and mammal) datasets. Model A is a conventional generalized linear model of abundance, model B adds a temporal autoregressive term, and model C uses an estimate of population growth rate as a response variable, with the option of including a term for density dependence. All models can be fit using Bayesian and non-Bayesian methods. Simulation results demonstrated that model C tended to have greater support for long-lived, lower-fecundity organisms (K life-history strategists), while model A, the simplest, tended to be supported for shorter-lived, high-fecundity organisms (r life-history strategists). Analysis of real-world fish and mammal datasets found that models A, B, and C each enjoyed support for at least some species, but sometimes yielded different insights. In particular, model C indicated effects of predictor variables that were not evident in analyses with models A and B. Bayesian and frequentist models yielded similar parameter estimates and performance. We conclude that relatively simple models are useful for testing hypotheses about the factors that influence abundance in time-series data, and can be appropriate choices for datasets that lack the information needed to fit more complicated models. When feasible, we advise fitting datasets with multiple models because they can provide complementary information.

}, keywords = {LTER-KNZ}, doi = {10.1002/ece3.v12.910.1002/ece3.9339}, url = {https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.9339}, author = {Wenger, S.J. and Stowe, E.S. and K. B. Gido and Freeman. M.C. and Kanno, Y. and Franssen, N.R. and Olden, Julian D. and Poff, N.L. and Walters, A.W. and Bumpers, P.M. and Mims, M.C. and Hooten, M.B. and Lu, Xinyi} } @article {6071, title = {Cultural conformity and persistence in Dickcissel song are higher in locations in which males show high site fidelity}, journal = {Ornithology}, volume = {139}, year = {2021}, pages = {1-17}, keywords = {LTER-KNZ}, doi = {10.1093/ornithology/ukab061}, url = {https://academic.oup.com/auk/article/doi/10.1093/ornithology/ukab061/6380842}, author = {Parker, Timothy H and Sousa, Bridget and Leu, Stephan T and Edmondson, Stacy and Foo, Cecily and Strauss, Amy and Kahl, Hanna and Ballinger, Kristen and Ross, Eric and {\ss}e Ruse, Mareile and Sandsten, Maria and Verheijen, Bram H F and Jensen, William} } @article {5986, title = {Do fine-scale experiments underestimate predator consumption rates?}, journal = {Journal of Animal Ecology}, volume = {90}, year = {2021}, pages = {2391 - 2403}, keywords = {LTER-KNZ}, doi = {10.1111/1365-2656.13549}, url = {https://onlinelibrary.wiley.com/toc/13652656/90/10}, author = {Lindsey A. Bruckerhoff and Pennock, C.A. and K. B. Gido} } @article {KNZ002034, title = {Is a drought a drought in grasslands? Productivity responses to different types of drought}, journal = {Oecologia}, year = {2021}, keywords = {LTER-KNZ}, author = {Carroll, C.J.W. and Slette, I.J. and Griffin-Nolan, R.J. and Baur, L.E. and Hoffman, A.M. and Denton, E.M. and Gray, J.E. and Post, A.K. and Johnston, M.K. and Yu, Q. and Collins, S.L. and Luo, Y. and Smith, M.D. and Knapp, A.K.} } @article {5996, title = {Experimental drought re-ordered assemblages of root-associated fungi across North American grasslands}, journal = {Journal of Ecology}, volume = {109}, year = {2021}, pages = {776 - 792}, keywords = {LTER-KNZ}, doi = {10.1111/1365-2745.13505}, url = {https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2745.13505}, author = {Lagueux, Devon and A. Jumpponen and Porras-Alfaro, A. and Herrera, Jose and Chung, Y. Anny and Baur, Lauren E. and M. D. Smith and Alan K. Knapp and S L Collins and Rudgers, Jennifer A.} } @article {KNZ002041, title = {Increasing effects of chronic nutrient enrichment on plant diversity loss and ecosystem productivity over time}, journal = {Ecology}, volume = {102}, year = {2021}, pages = {e03218}, abstract = {

Human activities are enriching many of Earth\’s ecosystems with biologically limiting mineral nutrients such as nitrogen (N) and phosphorus (P). In grasslands, this enrichment generally reduces plant diversity and increases productivity. The widely demonstrated positive effect of diversity on productivity suggests a potential negative feedback, whereby nutrient-induced declines in diversity reduce the initial gains in productivity arising from nutrient enrichment. In addition, plant productivity and diversity can be inhibited by accumulations of dead biomass, which may be altered by nutrient enrichment. Over longer timeframes, nutrient addition may increase soil fertility by increasing soil organic matter and nutrient pools. We examined the effects of 5-11 years of nutrient addition at 47 grasslands in twelve countries. Nutrient enrichment increased aboveground live biomass and reduced plant diversity at nearly all sites, and these effects became stronger over time. We did not find evidence that nutrient-induced losses of diversity reduced the positive effects of nutrients on biomass, however nutrient effects on live biomass increased more slowly at sites where litter was also increasing, regardless of plant diversity. This work suggests that short-term experiments may underestimate the long-term nutrient enrichment effects on global, grassland ecosystems.

}, keywords = {LTER-KNZ}, doi = {10.1002/ecy.3218}, url = {https://onlinelibrary.wiley.com/doi/10.1002/ecy.3218}, author = {Seabloom, E.W. and Adler, P.B. and Alberti, J. and Biederman, L. and Buckley, Y.M. and Cadotte, M.W. and S.L Collins and Dee, L. and Fay, P.A. and Firn, J. and Hagenah, N. and Harpole, W. S. and Hautier, Y. and Hector, A. and Hobbie, S.E. and Isbell, F. and Knops, J.M.H. and Kimberly J. Komatsu and Laungani, R. and MacDougall, A. and McCulley, R.L. and Moore, J.L. and Morgan, J.W. and Ohlert, T. and Prober, S.M. and Risch, A.C. and Schuetz, M. and Stevens, C.J. and Borer, E.T.} } @article {KNZ002045, title = {Mechanisms influencing physically sequestered soil carbon in temperate restored grasslands in South Africa and North America}, journal = {Biogeochemistry}, year = {2021}, abstract = {

Sequestering carbon (C) into stable soil pools has potential to mitigate increasing atmospheric carbon dioxide concentrations. Carbon accrues in grassland soil restored from cultivation, but the amount of physically protected C (here measured as microaggregate-within-macroaggregate C) and predominant mechanisms of accrual are not well understood. We modeled the rate of physically protected carbon accrued in three mesic temperate perennial restored grasslands from cross-continental regions using datasets with a wide range of restoration ages from northeast Kansas, USA; southeast Nebraska, USA; and northeast Free State, South Africa. Further, we investigated major controls on the amount of physically protected C in each site using structural equation modeling. Variables in the structural equation model were root biomass, root C:N ratio, soil structure (indicated by bulk density, percent of macroaggregates on a per whole soil mass basis, and percent of microaggregate-within-macroaggregates on a per macroaggregate mass basis), microbial composition (indicated by microbial biomass C, total phospholipid fatty acid [PLFA] biomass, and PLFA biomass of arbuscular mycorrhizae fungi [AMF] biomass), and microaggregate-within-macroaggregate C on a per whole soil mass basis. Across all sites, physically protected C accrued at a rate of 16\ \±\ 5 g m\−2 year\−1. Data from South Africa fit an a priori metamodel developed for northeast KS that hypothesized physically protected C could be explained as a function of microbial composition, soil structure, root C:N ratio, and root biomass (listed in order of strength of direct effect on physically protected C). In contrast to the model-based hypothesis, root C:N ratio was the strongest influence (negative) on physically protected C in South Africa. The lesser effect of AMF on physically protected C in South Africa was consistent with lower AMF biomass in arid environments. The hypothesized model did not fit southeast Nebraska data possibly due to high (~\ 30\%) clay content. Overall, these results suggest that physically protected C in soil with moderate amounts of clay (more than 10\% and less than 30\%) can be predicted with knowledge of roots (biomass and C:N ratio), microbial biomass, and soil aggregation.

}, keywords = {LTER-KNZ}, doi = {10.1007/s10533-021-00774-y}, url = {https://link.springer.com/article/10.1007/s10533-021-00774-y}, author = {Scott, D.A. and Bach, Elizabeth M. and Du Preez, Chris C. and Six, Johan and Baer, S.G.} } @article {5970, title = {Negative effects of nitrogen override positive effects of phosphorus on grassland legumes worldwide}, journal = {Proceedings of the National Academy of Sciences}, volume = {118}, year = {2021}, pages = {e2023718118}, keywords = {LTER-KNZ}, doi = {10.1073/pnas.2023718118}, url = {http://www.pnas.org/lookup/doi/10.1073/pnas.2023718118}, author = {Tognetti, Pedro M. and Prober, Suzanne M. and B{\'a}ez, Selene and Chaneton, Enrique J. and Firn, Jennifer and Risch, Anita C. and Schuetz, Martin and Simonsen, Anna K. and Yahdjian, Laura and Borer, Elizabeth T. and Seabloom, Eric W. and Arnillas, Carlos Alberto and Bakker, Jonathan D. and Brown, Cynthia S. and Cadotte, Marc W. and Caldeira, Maria C. and Daleo, Pedro and Dwyer, John M. and Fay, Philip A. and Gherardi, Laureano A. and Hagenah, Nicole and Hautier, Yann and Kimberly J. Komatsu and McCulley, Rebecca L. and Price, Jodi N. and Standish, Rachel J. and Stevens, Carly J. and Wragg, Peter D. and Sankaran, Mahesh} } @article {5989, title = {RivFishTIME: A global database of fish time-series to study global change ecology in riverine systems}, journal = {Global Ecology and Biogeography}, volume = {30}, year = {2021}, pages = {38 - 50}, keywords = {LTER-KNZ}, doi = {10.1111/geb.13210}, url = {https://onlinelibrary.wiley.com/doi/epdf/10.1111/geb.13210}, author = {Comte, Lise and Carvajal, Juan and Tedesco, Pablo A. and Giam, Xingli and Brose, Ulrich and Er{\H o}s, Tibor and Filipe, Ana F. and Fortin, Marie-Jos{\'e}e and Irving, Katie and Jacquet, Claire and Larsen, Stefano and Sharma, Sapna and Ruhi, Albert and Becker, Fernando G. and Casatti, Lilian and Castaldelli, Giuseppe and Dala-Corte, Renato B. and Davenport, Stephen R. and Franssen, Nathan R. and Garc{\'\i}a-Berthou, Emili and Gavioli, Anna and K. B. Gido and Jimenez-Segura, Luz and Leit{\~a}o, Rafael P. and McLarney, Bill and Meador, Jason and Milardi, Marco and Moffatt, David B. and Occhi, Thiago V. T. and Pompeu, Paulo S. and Propst, David L. and Pyron, Mark and Salvador, Gilberto N. and Stefferud, Jerome A. and Sutela, Tapio and Taylor, Christopher and Terui, Akira and Urabe, Hirokazu and Vehanen, Teppo and Vitule, Jean R. S. and Zeni, Jaquelini O. and Olden, Julian D.}, editor = {Bahn, Volker} } @article {KNZ002060, title = {SoDaH: the SOils DAta Harmonization database, an open-source synthesis of soil data from research networks, version 1.0}, journal = {Earth System Science Data}, volume = {13}, year = {2021}, pages = {1843 - 1854}, keywords = {LTER-KNZ}, doi = {10.5194/essd-13-1843-2021}, url = {https://essd.copernicus.org/articles/13/1843/2021/essd-13-1843-2021.pdf}, author = {Wieder, William R. and Pierson, Derek and Earl, Stevan and Lajtha, Kate and S.G. Baer and Ballantyne, Ford and Berhe, Asmeret Asefaw and Billings, Sharon A. and Brigham, Laurel M. and Chacon, Stephany S. and Fraterrigo, Jennifer and Frey, Serita D. and Georgiou, Katerina and de Graaff, Marie-Anne and Grandy, A. Stuart and Hartman, Melannie D. and Hobbie, Sarah E. and Johnson, Chris and Kaye, Jason and Kyker-Snowman, Emily and Litvak, Marcy E. and Mack, Michelle C. and Malhotra, Avni and Moore, Jessica A. M. and Nadelhoffer, Knute and Rasmussen, Craig and Silver, Whendee L. and Sulman, Benjamin N. and Walker, Xanthe and Weintraub, Samantha} } @article {5992, title = {State changes: insights from the U.S. Long Term Ecological Research Network}, journal = {Ecosphere}, volume = {12}, year = {2021}, month = {e03433}, keywords = {LTER-KNZ}, doi = {10.1002/ecs2.v12.510.1002/ecs2.3433}, url = {https://onlinelibrary.wiley.com/toc/21508925/12/5}, author = {Zinnert, Julie C. and Nippert, J.B. and Rudgers, Jennifer A. and Pennings, Steven C. and Gonz{\'a}lez, Grizelle and Alber, Merryl and S.G. Baer and J. M. Blair and Burd, Adrian and S L Collins and Craft, Christopher and Di Iorio, Daniela and Dodds, Walter K. and Groffman, Peter M. and Herbert, Ellen and Hladik, Christine and Li, Fan and Litvak, Marcy E. and Newsome, Seth and O{\textquoteright}Donnell, John and Pockman, William T. and Schalles, John and Young, Donald R.} } @article {6115, title = {Temporal rarity is a better predictor of local extinction risk than spatial rarity}, journal = {Ecology}, volume = {102}, year = {2021}, keywords = {LTER-KNZ}, doi = {10.1002/ecy.3504}, url = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1002/ecy.3504}, author = {Wilfahrt, Peter A. and Asmus, Ashley L. and Seabloom, Eric W. and Henning, Jeremiah A. and Adler, Peter and Arnillas, Carlos A. and Bakker, Jonathan D. and Biederman, Lori and Brudvig, Lars A. and Cadotte, Marc and Daleo, Pedro and Eskelinen, Anu and Firn, Jennifer and Harpole, W. Stanley and Hautier, Yann and Kirkman, K.P. and Kimberly J. Komatsu and Laungani, Ramesh and MacDougall, Andrew and McCulley, Rebecca L. and Moore, Joslin L. and Morgan, John W. and Mortensen, Brent and Ochoa Hueso, Raul and Ohlert, Timothy and Power, Sally A. and Price, Jodi and Risch, Anita C. and Schuetz, Martin and Shoemaker, Lauren and Stevens, Carly and Strauss, Alexander T. and Tognetti, Pedro M. and Virtanen, Risto and Borer, Elizabeth T.} } @article {6003, title = {Why coordinated distributed experiments should go global}, journal = {BioScience}, volume = {71}, year = {2021}, pages = {918 - 927}, keywords = {LTER-KNZ}, doi = {10.1093/biosci/biab033}, url = {https://academic.oup.com/bioscience/article/71/9/918/6259352}, author = {Yahdjian, Laura and Sala, Osvaldo E and Pi{\~N}Eiro-Guerra, Juan Manuel and Alan K. Knapp and Collins, Scott L. and Phillips, Richard P and M. D. Smith} } @article {KNZ001993, title = {Biomass loss and change in species dominance shift stream community excretion stoichiometry during severe drought}, journal = {Freshwater Biology}, volume = {65}, year = {2020}, pages = {403-416}, abstract = {

\ \ \  1. Animals contribute significantly to nutrient cycling through excretion, but most studies consider their effects under relatively benign abiotic conditions. Disturbances such as drought may alter animals\’ nutrient contributions through shifts in species composition and biomass. Headwater streams are particularly vulnerable to extreme climate events and thus might show rapid changes in stream biota and their ecosystem effects.
\ \ \  2. We tested how biomass and subsequent ecosystem effects (nutrient cycling) of an intermittent prairie stream community changed during a drought. We quantified the biomass and contributions to nutrient cycling for assemblages comprising fishes, crayfish, and tadpoles in 12 isolated pools over 3 months encompassing the harshest drought on record for Kings Creek, KS, U.S.A. We predicted that macroconsumer biomass would decline with pool surface area and that differences in macroconsumer biomass and taxonomic composition would lead to different contributions of pool assemblages to nutrient cycling.
\ \ \  3. The biomass of pool assemblages declined with decreasing pool size, a pattern apparently driven by mortality, emigration, or metamorphosis. We also observed a change in assemblage structure of drying pools during drought relative to pool size, shifting dominance toward species with more drought-resistant traits. Accordingly, assemblage nitrogen (N) excretion rates declined as pool biomass was reduced, leading to a 58\% reduction in N available to epilithic biofilms. Phosphorus (P) excretion rates declined from June to July, but increased in August, as species with high P excretion rates maintained similar proportional biomass and biomass of a non-native fish increased. Molar N:P of pool assemblage excretion declined significantly throughout the drought and coincided with loss of southern redbelly dace (Chrosomus erythrogaster: Cyprinidae).
\ \ \  4. Animal-mediated nutrient cycling was altered by the loss of biomass and stoichiometric traits of taxa that differed in their occurrences and ability to tolerate abiotic conditions during drought. Elevated availability of dissolved N in isolated pools may increase N uptake rates by biofilms during drought conditions, indicating the importance of N excreted by aggregated macroconsumers, especially those with unique stoichiometric traits. While the significance of shifts in the composition of freshwater communities to ecosystems is not entirely known, additional losses in ecosystem function and changes in community structure may follow episodes of severe drought.

}, keywords = {LTER-KNZ}, doi = {10.1111/fwb.13433}, url = {https://onlinelibrary.wiley.com/doi/pdf/10.1111/fwb.13433}, author = {Hopper, Garrett W. and K. B. Gido and Pennock, Casey A. and Hedden, Skyler C. and Guinnip, James P. and Fisher, Molly A. and Tobler, Courtney M. and Hedden, Crosby K. and Lindsey A. Bruckerhoff} } @article {KNZ001995, title = {Bottom-up when it is not top-down: Predators and plants control biomass of grassland arthropods}, journal = {Journal of Animal Ecology}, volume = {89}, year = {2020}, month = {1286-1294}, abstract = {

1) We investigate where bottom-up and top-down control regulates ecological communities as a mechanism linking ecological gradients to the geography of consumer abundance and biomass. We use standardized surveys of 54 North American grasslands to test alternate hypotheses predicting 100-fold shifts in the biomass of four common grassland arthropod taxa\—Auchenorrhyncha, sucking herbivores, Acrididae, chewing herbivores, Tettigoniidae, omnivores, and Araneae, predators.

2) Bottom-up models predict that consumer biomass tracks plant quantity (e.g. productivity and standing biomass) and quality (nutrient content) and that ectotherm access to food increases with temperature. Each of the focal trophic groups responded differently to these drivers: the biomass of sucking herbivores and omnivores increased with plant biomass; that of chewing herbivores tracked plant quality; and predator biomass did not depend on plant quality, plant quantity, or temperature.

3) The exploitation ecosystem hypothesis (EEH) is a top-down hypothesis that predicts a shift from resource limitation of herbivores when plant production is low, to predator limitation when plant production is high. In grasslands where spider biomass was low, herbivore biomass increased with plant biomass, whereas bottom-up structuring was not evident when spiders were abundant. Furthermore, neither predator biomass nor trophic position (via stable isotope analysis) increased with plant biomass, suggesting predators themselves are top-down limited.

4) Stable isotope analysis revealed that trophic position of the chewing herbivore and omnivore increased significantly with plant biomass, suggesting these groups increased scavenging and meat consumption in grasslands with higher carbohydrate availability.

5) Taken together, our snapshot sampling documents gradients of food web structure across 54 grasslands, consistent with multiple hypotheses of bottom-up and top-down regulation.

}, keywords = {LTER-KNZ}, doi = {10.1111/1365-2656.13191}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/1365-2656.13191}, author = {Welti, Ellen A. R. and Prather, Rebecca M. and Sanders, Nathan J. and deBeurs, Kirsten M. and Kaspari, Michael} } @article {KNZ002051, title = {Connections and feedback: Aquatic, plant, and soil microbiomes in heterogeneous and changing environments}, journal = {BioScience}, volume = {70}, year = {2020}, pages = {548 - 562}, abstract = {

Plant, soil, and aquatic microbiomes interact, but scientists often study them independently. Integrating knowledge across these traditionally separate subdisciplines will generate better understanding of microbial ecological properties. Interactions among plant, soil, and aquatic microbiomes, as well as anthropogenic factors, influence important ecosystem processes, including greenhouse gas fluxes, crop production, nonnative species control, and nutrient flux from terrestrial to aquatic habitats. Terrestrial microbiomes influence nutrient retention and particle movement, thereby influencing the composition and functioning of aquatic microbiomes, which, themselves, govern water quality, and the potential for harmful algal blooms. Understanding how microbiomes drive links among terrestrial (plant and soil) and aquatic habitats will inform management decisions influencing ecosystem services. In the present article, we synthesize knowledge of microbiomes from traditionally disparate fields and how they mediate connections across physically separated systems. We identify knowledge gaps currently limiting our abilities to actualize microbiome management approaches for addressing environmental problems and optimize ecosystem services.

}, keywords = {LTER-KNZ}, doi = {10.1093/biosci/biaa046}, url = {https://academic.oup.com/bioscience/article/70/7/548/5826958}, author = {W. K. Dodds and L.H. Zeglin and Ramos, R.J. and Platt, T.G. and Pandey, A. and Michaels, T. and Masigol, M. and Klompen, A.M.L. and Kelly, M.C. and A. Jumpponen and Hauser, E. and Hansen, P.M. and Greer, M.J. and Fattahi, N. and Delavaux, C.S. and Connell, R.K. and Billings, S. and Bever, J.D. and Barua, N. and Agusto, F.B.} } @article {KNZ002029, title = {Global impacts of fertilization and herbivore removal on soil net nitrogen mineralization are modulated by local climate and soil properties}, journal = {Global Change Biology}, volume = {26}, year = {2020}, abstract = {

Soil nitrogen (N) availability is critical for grassland functioning. However, human activities have increased the supply of biologically limiting nutrients, and changed the density and identity of mammalian herbivores. These anthropogenic changes may alter net soil N mineralization (soil net Nmin), that is, the net balance between N mineralization and immobilization, which could severely impact grassland structure and functioning. Yet, to date, little is known about how fertilization and herbivore removal individually, or jointly, affect soil net Nmin across a wide range of grasslands that vary in soil and climatic properties. Here we collected data from 22 grasslands on five continents, all part of a globally replicated experiment, to assess how fertilization and herbivore removal affected potential (laboratory-based) and realized (field-based) soil net Nmin. Herbivore removal in the absence of fertilization did not alter potential and realized soil net Nmin. However, fertilization alone and in combination with herbivore removal consistently increased potential soil net Nmin. Realized soil net Nmin, in contrast, significantly decreased in fertilized plots where herbivores were removed. Treatment effects on potential and realized soil net Nmin were contingent on site-specific soil and climatic properties. Fertilization effects on potential soil net Nmin were larger at sites with higher mean annual precipitation (MAP) and temperature of the wettest quarter (T.q.wet). Reciprocally, realized soil net Nmin declined most strongly with fertilization and herbivore removal at sites with lower MAP and higher T.q.wet. In summary, our findings show that anthropogenic nutrient enrichment, herbivore exclusion and alterations in future climatic conditions can negatively impact soil net Nmin across global grasslands under realistic field conditions. This is an important context-dependent knowledge for grassland management worldwide.

}, keywords = {LTER-KNZ}, doi = {10.1111/gcb.15308}, url = {https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.15308}, author = {Risch, Anita C. and Zimmermann, Stefan and Moser, Barbara and Sch{\"u}tz, Martin and Hagedorn, Frank and Firn, Jennifer and Fay, Philip A. and Adler, Peter B. and Biederman, Lori A. and J. M. Blair and Borer, Elizabeth T. and Broadbent, Arthur A. D. and Brown, Cynthia S. and Cadotte, Marc W. and Caldeira, Maria C. and Davies, Kendi F. and Virgilio, Augustina and Eisenhauer, Nico and Eskelinen, Anu and Knops, Johannes M. H. and MacDougall, Andrew S. and McCulley, Rebecca L. and Melbourne, Brett A. and Moore, Joslin L. and Power, Sally A. and Prober, Suzanne M. and Seabloom, Eric W. and Siebert, Julia and Silveira, Maria L. and Speziale, Karina L. and Stevens, Carly J. and Tognetti, Pedro M. and Virtanen, Risto and Yahdjian, Laura and Ochoa-Hueso, Raul} } @article {6208, title = {Impacts of ammonia volatilization from broadcast urea on winter wheat production}, journal = {Agronomy Journal}, volume = {112}, year = {2020}, pages = {3758 - 3772}, keywords = {LTER-KNZ}, doi = {10.1002/agj2.v112.510.1002/agj2.20371}, url = {https://acsess.onlinelibrary.wiley.com/doi/10.1002/agj2.20371}, author = {Perin, Vinicius and Santos, Eduardo A. and Lollato, Romulo and Ruiz-Diaz, Dorivar and Kluitenberg, Gerard J.} } @article {KNZ002055, title = {Micronutrients enhance macronutrient effects in a meta-analysis of grassland arthropod abundance}, journal = {Global Ecology and Biogeography}, volume = {29}, year = {2020}, pages = {2273-2288}, keywords = {LTER-KNZ}, doi = {10.1111/geb.13196}, url = {https://onlinelibrary.wiley.com/doi/10.1111/geb.13196}, author = {Prather, R.M. and Castillioni, K. and Kaspari, M. and Souza, L. and Prather, C.M. and Reihart, R.W. and Welti, Ellen A. R.} } @article {6296, title = {No difference in herbivory preferences among ecotypes of big bluestem (Andropogon gerardii)}, journal = {Transactions of the Kansas Academy of Science}, volume = {123}, year = {2020}, pages = {151}, keywords = {LTER-KNZ}, doi = {10.1660/062.123.0112}, url = {https://bioone.org/journals/transactions-of-the-kansas-academy-of-science/volume-123/issue-1-2/062.123.0112/No-Difference-in-Herbivory-Preferences-Among-Ecotypes-of-Big-Bluestem/10.1660/062.123.0112.full}, author = {Pittenger, Madison S. and Maricle, Keri L. and S.G. Baer and Johnson, Loretta C. and Maricle, Brian R.} } @article {KNZ002003, title = {Nowhere to swim: interspecific responses of prairie stream fishes in isolated pools during severe drought}, journal = {Aquatic Sciences}, volume = {82}, year = {2020}, abstract = {

Extreme drying can dramatically shift abiotic characteristics of streams and species respond differently as conditions change. We modified a conceptual model describing responses of aquatic invertebrate assemblages to stream drying to facilitate predictions of fish assemblage shifts in which thresholds of physiochemical gradients lead to punctuated losses of fish diversity as stream connectivity diminishes. We tested the applicability of this model during a record-breaking drought that reduced a perennial reach of a headwater prairie stream to a series of 12 isolated pools with variable levels of hyporheic connectivity that was associated with pool volume. We tracked fish assemblage structure in pools over seven weeks and measured abiotic conditions. Inter-specific differences in drought resistance traits were tested in the lab (i.e., thermal and hypoxia tolerance) for common species experiencing drought conditions. Species richness declined rapidly with pool volume associated with hyporheic connectivity. Abundance of the most common species prior to drought, Chrosomus erythrogaster (southern redbelly dace) declined 95\% and was extirpated from five pools during drought due to its low thermal tolerance. Despite being the least tolerant to hypoxia, Campostoma anomalum (central stoneroller) populations persisted in most pools. The remaining pools became dominated by a non-native extremophile fish, Gambusia affinis (western mosquitofish) and abundances of less resistant native species declined. Our study demonstrates that richness in drying pools is driven by factors associated with pool volume, and assemblage composition shifts from dominance by native species adapted to variable hydrological conditions to non-native species able to resist increasing temperatures and hypoxia. Sudden species loss associated with reduced stream connectivity can shift abundance patterns of prairie stream fish communities with potentially lagged effects on population and community dynamics.

}, keywords = {LTER-KNZ}, issn = {1015-1621}, doi = {10.1007/s00027-020-0716-2}, url = {http://link.springer.com/10.1007/s00027-020-0716-2}, author = {Hopper, Garrett W. and K. B. Gido and Pennock, Casey A. and Hedden, Skyler C. and Frenette, Bryan D. and Barts, Nick and Hedden, Crosby K. and Lindsey A. Bruckerhoff} } @article {KNZ002042, title = {Nutrients cause grassland biomass to outpace herbivory}, journal = {Nature Communications}, volume = {11}, year = {2020}, pages = {6036}, keywords = {LTER-KNZ}, doi = {10.1038/s41467-020-19870-y}, url = {http://www.nature.com/articles/s41467-020-19870-y}, author = {Borer, E. T. and Harpole, W. S. and Adler, P. B. and Arnillas, C. A. and Bugalho, M. N. and Cadotte, M. W. and Caldeira, M. C. and Campana, S. and Dickman, C. R. and Dickson, T. L. and Donohue, I. and Eskelinen, A. and Firn, J. L. and Graff, P. and Gruner, D. S. and Heckman, R. W. and Koltz, A. M. and Kimberly J. Komatsu and Lannes, L. S. and MacDougall, A. S. and Martina, J. P. and Moore, J. L. and Mortensen, B. and Ochoa-Hueso, R. and Olde Venterink, H. and Power, S. A. and Price, J. N. and Risch, A. C. and Sankaran, M. and sch{\"u}tz, M. and Sitters, J. and Stevens, C. J. and Virtanen, R. and Wilfahrt, P. A. and Seabloom, E. W.} } @article {KNZ002014, title = {Rainfall-manipulation experiments as simulated by terrestrial biosphere models: where do we stand?}, journal = {Global Change Biology}, volume = {26}, year = {2020}, pages = {3336{\textendash}3355}, abstract = {

Changes in rainfall amounts and patterns have been observed and are expected to continue in the near future with potentially significant ecological and societal consequences. Modelling vegetation responses to changes in rainfall is thus crucial to project water and carbon cycles in the future. In this study, we present the results of a new model-data intercomparison project, where we tested the ability of ten terrestrial biosphere models to reproduce observed sensitivity of ecosystem productivity to rainfall changes at ten sites across the globe, in nine of which, rainfall exclusion and/or irrigation experiments had been performed.

The key results are:
(a) Inter-model variation is generally large and model agreement varies with time scales. In severely water limited sites, models only agree on the interannual variability of evapotranspiration and to a smaller extent gross primary productivity. In more mesic sites model agreement for both water and carbon fluxes is typically higher on fine (daily-monthly) time scales and reduces on longer (seasonal-annual) scales.
(b) Models on average overestimate the relationship between ecosystem productivity and mean rainfall amounts across sites (in space) and have a low capacity in reproducing the temporal (interannual) sensitivity of vegetation productivity to annual rainfall at a given site, even though observation uncertainty is comparable to inter-model variability.
(c) Most models reproduced the sign of the observed patterns in productivity changes in rainfall manipulation experiments but had a low capacity in reproducing the observed magnitude of productivity changes. Models better reproduced the observed productivity responses due to rainfall exclusion than addition.
(d) All models attribute ecosystem productivity changes to the intensity of vegetation stress and peak leaf area, whereas the impact of the change in growing season length is negligible. The relative contribution of the peak leaf area and vegetation stress intensity was highly variable among models.

}, keywords = {LTER-KNZ}, doi = {10.1111/gcb.15024}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.15024}, author = {Paschalis, Athanasios and Fatichi, Simone and Zscheischler, Jakob and Ciais, Philippe and Michael Bahn and Lena R. Boysen and Chang, Jinfeng and De Kauwe, Martin and Estiarte, Marc and Goll, Daniel and Hanson, Paul J. and Harper, Anna B. and Hou, Enqing and Kigel, Jaime and Alan K. Knapp and Larsen, Klaus Steenberg and Li, Wei and Lienert, Sebastian and Luo, Yiqi and Meir, Patrick and Nabel, Julia E.M.S. and Ogaya, Rom{\`a} and Parolari, Anthony J and Peng, Changhui and Pe{\~n}uelas, Josep and Pongratz, Julia and Rambal, Serge and Schmidt, Inger Kappel and Shi, Hao and Sternberg, Marcelo and Tian, Hanqin and Tschumi, Elisabeth and Ukkola, Anna and Vicca, Sara and Viovy, Nicolas and Wang, -Ping and Wang, Zhuonan and Williams, Karina and Wu, Donghai and Zhu, Qiuan} } @article {KNZ002015, title = {Repeated fire shifts carbon and nitrogen cycling by changing plant inputs and soil decomposition across ecosystems}, journal = {Ecological Monographs}, volume = {90}, year = {2020}, pages = {e01409}, abstract = {

Fires shape the biogeochemistry and functioning of many ecosystems, and fire frequencies are changing across much of the globe. Frequent fires can change soil carbon (C) and nitrogen (N) storage by altering the quantity and chemistry of plant inputs through changes in plant biomass and composition as well as altering decomposition of soil organic matter. How decomposition rates change with shifting inputs remains uncertain because most studies focus on the effects of single fires, where transient changes may not reflect responses to decadal changes in burning frequencies. Here, we sampled seven sites exposed to different fire frequencies. In four of the sites, we intensively sampled both soils and plant communities across four ecosystems in North America and Africa spanning tropical savanna, temperate coniferous savanna, temperate broadleaf savanna, and temperate coniferous forest ecosystems. Each site contained multiple plots burned frequently for 33-61 years and nearby plots that had remained unburned over the same period replicated at the landscape scale. Across all sites, repeatedly burned plots had 25-185\% lower bulk soil C and N concentrations but also 2-10-fold lower potential decomposition of organic matter compared to unburned sites. Soil C and N concentrations and extracellular enzyme activities declined with frequent fire because fire reduced both plant biomass inputs into soils and dampened the localized enrichment effect of tree canopies. Examination of soil extracellular enzyme activities revealed that fire decreased the potential turnover of organic matter in the forms of cellulose, starch, and chitin (p\<0.0001) but not polyphenol and lignin (p=0.09), suggesting a shift in soil C and N cycling. Inclusion of δ13C data from three additional savanna sites (19-60 years of altered fire frequencies) showed that soil C losses were largest in sites where estimated tree inputs into soils declined the most (r2=0.91, p\<0.01). In conclusion, repeated burning reduced C and N storage, consistent with previous studies, but fire also reduced potential decomposition, likely contributing to slower C and N cycling. Trees were important in shaping soil carbon responses across sites, but the magnitude of tree effects differed and depended on how tree biomass inputs into soil responded to fire.

}, keywords = {LTER-KNZ}, doi = {10.1002/ecm.1409}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/ecm.1409}, author = {Pellegrini, Adam.F.A. and Hobbie, Sarah E. and Reich, Peter B. and A. Jumpponen and Brookshire, E.N. Jack and Caprio, Anthony C. and Coetsee, Corli and Jackson, Robert B.} } @article {KNZ002028, title = {Resolving the Dust Bowl paradox of grassland responses to extreme drought}, journal = {Proceedings of the National Academy of Sciences}, volume = {117}, year = {2020}, pages = {22249-22255}, abstract = {

During the 1930s Dust Bowl drought in the central United States, species with the C3 photosynthetic pathway expanded throughout C4-dominated grasslands. This widespread increase in C3 grasses during a decade of low rainfall and high temperatures is inconsistent with well-known traits of C3 vs. C4 pathways. Indeed, water use efficiency is generally lower, and photosynthesis is more sensitive to high temperatures in C3 than C4 species, consistent with the predominant distribution of C3 grasslands in cooler environments and at higher latitudes globally. We experimentally imposed extreme drought for 4 y in mixed C3/C4 grasslands in Kansas and Wyoming and, similar to Dust Bowl observations, also documented three- to fivefold increases in C3/C4 biomass ratios. To explain these paradoxical responses, we first analyzed long-term climate records to show that under nominal conditions in the central United States, C4 grasses dominate where precipitation and air temperature are strongly related (warmest months are wettest months). In contrast, C3 grasses flourish where precipitation inputs are less strongly coupled to warm temperatures. We then show that during extreme drought years, precipitation\–temperature relationships weaken, and the proportion of precipitation falling during cooler months increases. This shift in precipitation seasonality provides a mechanism for C3 grasses to respond positively to multiyear drought, resolving the Dust Bowl paradox. Grasslands are globally important biomes and increasingly vulnerable to direct effects of climate extremes. Our findings highlight how extreme drought can indirectly alter precipitation seasonality and shift ecosystem phenology, affecting function in ways not predictable from key traits of C3 and C4 species.

}, keywords = {LTER-KNZ}, doi = {10.1073/pnas.1922030117}, url = {http://www.pnas.org/lookup/doi/10.1073/pnas.1922030117}, author = {Alan K. Knapp and Chen, Anping and Griffin-Nolan, Robert J. and Baur, Lauren E. and Carroll, Charles J.W. and Gray, Jesse E. and Hoffman, Ava M. and Li, Xiran and Post, Alison K. and Slette, Ingrid J. and S L Collins and Luo, Yiqi and Smith, Melinda D.} } @article {KNZ002037, title = {SoDaH: the SOils DAta Harmonization database, an open-source synthesis of soil data from research networks, version 1.0}, journal = {Earth System Science Data Discussion}, year = {2020}, keywords = {LTER-KNZ}, doi = {10.5194/essd-2020-195}, url = {https://essd.copernicus.org/preprints/essd-2020-195/}, author = {Wieder, W.R. and Pierson, D. and Earl, S.R. and Lajtha, K. and Baer, S. and Ballantyne, F. and Berhe, A.A. and Billings, S. and Brigham, L.M. and Chacon, S.S. and Fraterrigo, J. and Frey, S.D. and Georgiou, K. and de Graaff, M. and Grandy, A.S. and Hartman, M.D. and Hobbie, S.E. and Johnson, C. and Kaye, J. and Snowman, E. and Litvak, M.E. and Mack, M.C. and Malhotra, A. and Moore, J.A.M. and Nadelhoffer, K. and Rasmussen, C. and Silver, W.L. and Sulman, B.N. and Walker, X. and Weintraub. S.} } @article {KNZ001944, title = {Assessing precipitation, evapotranspiration, and NDVI as controls of U.S. Great Plains plant production}, journal = {Ecosphere}, volume = {10}, year = {2019}, pages = {e02889}, abstract = {

Productivity throughout the North American Great Plains grasslands is generally considered to be water limited, with the strength of this limitation increasing as precipitation decreases. We hypothesize that cumulative actual evapotranspiration water loss (AET) from April to July is the precipitation-related variable most correlated to aboveground net primary production (ANPP) in the U.S. Great Plains (GP). We tested this by evaluating the relationship of ANPP to AET, precipitation, and plant transpiration (Tr). We used multi-year ANPP data from five sites ranging from semiarid grasslands in Colorado and Wyoming to mesic grasslands in Nebraska and Kansas, mean annual NRCS ANPP, and satellite-derived normalized difference vegetation index (NDVI) data. Results from the five sites showed that cumulative April-to-July AET, precipitation, and Tr were well correlated (R2: 0.54\–0.70) to annual changes in ANPP for all but the wettest site. AET and Tr were better correlated to annual changes in ANPP compared to precipitation for the drier sites, and precipitation in August and September had little impact on productivity in drier sites. April-to-July cumulative precipitation was best correlated (R2 = 0.63) with interannual variability in ANPP in the most mesic site, while AET and Tr were poorly correlated with ANPP at this site. Cumulative growing season (May-to-September) NDVI (iNDVI) was strongly correlated with annual ANPP at the five sites (R2 = 0.90). Using iNDVI as a surrogate for ANPP, we found that county-level cumulative April\–July AET was more strongly correlated to ANPP than precipitation for more than 80\% of the GP counties, with precipitation tending to perform better in the eastern more mesic portion of the GP. Including the ratio of AET to potential evapotranspiration (PET) improved the correlation of AET to both iNDVI and mean county-level NRCS ANPP. Accounting for how different precipitation-related variables control ANPP (AET in drier portion, precipitation in wetter portion) provides opportunity to develop spatially explicit forecasting of ANPP across the GP for enhancing decision-making by land managers and use of grassland ANPP for biofuels.

}, keywords = {LTER-KNZ}, doi = {10.1002/ecs2.2889}, url = {https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecs2.2889}, author = {Chen, Maosi and Parton, William J. and Hartman, Melannie D. and Del Grosso, Stephen J. and Smith, William K. and Alan K. Knapp and Lutz, Susan and Derner, Justin D. and Tucker, Compton J. and Ojima, Dennis S. and Volesky, Jerry D. and Stephenson, Mitchell B. and Schacht, Walter H. and Gao, Wei} } @article {KNZ001945, title = {Belowground biomass response to nutrient enrichment depends on light limitation across globally distributed grasslands}, journal = {Ecosystems}, volume = {22}, year = {2019}, pages = {1466{\textendash}1477}, abstract = {

Anthropogenic activities are increasing nutrient inputs to ecosystems worldwide, with consequences for global carbon and nutrient cycles. Recent meta-analyses show that aboveground primary production is often co-limited by multiple nutrients; however, little is known about how root production responds to changes in nutrient availability. At twenty-nine grassland sites on four continents, we quantified shallow root biomass responses to nitrogen (N), phosphorus (P) and potassium plus micronutrient enrichment and compared below- and aboveground responses. We hypothesized that optimal allocation theory would predict context dependence in root biomass responses to nutrient enrichment, given variation among sites in the resources limiting to plant growth (specifically light versus nutrients). Consistent with the predictions of optimal allocation theory, the proportion of total biomass belowground declined with N or P addition, due to increased biomass aboveground (for N and P) and decreased biomass belowground (N, particularly in sites with low canopy light penetration). Absolute root biomass increased with N addition where light was abundant at the soil surface, but declined in sites where the grassland canopy intercepted a large proportion of incoming light. These results demonstrate that belowground responses to changes in resource supply can differ strongly from aboveground responses, which could significantly modify predictions of future rates of nutrient cycling and carbon sequestration. Our results also highlight how optimal allocation theory developed for individual plants may help predict belowground biomass responses to nutrient enrichment at the ecosystem scale across wide climatic and environmental gradients.

}, keywords = {LTER-KNZ, belowground biomass, Fertilization, nitrogen, Nutrient Network, optimal allocation, phosphorus roots}, doi = {10.1007/s10021-019-00350-4}, url = {https://link.springer.com/article/10.1007\%2Fs10021-019-00350-4}, author = {Cleland, Elsa E. and Lind, Eric M. and DeCrappeo, Nicole M. and DeLorenze, Elizabeth and Wilkins, Rachel Abbott and P. Adler and Bakker, Jonathan D. and Brown, Cynthia S. and Davies, Kendi F. and Esch, Ellen and Firn, Jennifer and Gressard, Scott and Gruner, Daniel S. and Hagenah, Nicole and Harpole, W. Stanley and Hautier, Yann and Hobbie, Sarah E. and Hofmockel, Kirsten S. and Kirkman, Kevin and Knops, Johannes and Kopp, Christopher W. and Kimberly J. La Pierre and MacDougall, Andrew and McCulley, Rebecca L. and Melbourne, Brett A. and Joslin L. Moore and Prober, Suzanne M. and Riggs, Charlotte and Risch, Anita C. and Schuetz, Martin and Stevens, Carly and Wragg, Peter D. and Wright, Justin and E.T. Borer and Seabloom, Eric W.} } @article {KNZ001962, title = {Evolution of carbonate and karst critical zones}, journal = {Chemical Geology}, volume = {527}, year = {2019}, pages = {119223}, abstract = {

Carbonate terrains (CT) underlie one-fifth of terrestrial, ice-free land and are an important supply of potable water to the world\&$\#$39;s population, and yet processes endemic to CT critical zones (CZ) and responses of these processes to climatic and anthropogenic pressures are not well understood. Given the rapid dissolution rates and ability to generate well-developed networks of secondary porosity these landscapes can be highly sensitive to impacts from climate change (e.g., modifications of temperature, precipitation, sea level) and human disturbance (e.g., water withdrawal/diversions, changes in land use/land cover). This special issue includes 16 papers focused on CT-CZ processes and potential responses to climatic and human perturbations. Five major themes emerge from these papers, namely: (1) anthropogenic climate and land use changes alter CT-CZ weathering rate and diagenesis, (2) metal and carbon fluxes in CT-CZ will respond to increasing hydrologic variance caused by climate change, (3) endogenous and exogenous processes operating over short time periods (\<10,000 yrs) form landscape patterns in carbonate terrains, (4) rates of carbonate mineral dissolution depend on vadose zone and soil thickness, and (5) open systems may not always promote greater carbonate weathering rates in CT-CZ. These findings reflect the importance of carbonate minerals in Earth\&$\#$39;s CZ, both in terms of processes unique to carbonate minerals, as well as a predictor of future responses to anthropogenic and environmental changes.

}, keywords = {LTER-KNZ}, doi = {10.1016/j.chemgeo.2019.06.023}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0009254119303183}, author = {Sullivan, P.L. and G. L. Macpherson and Martin, J.B. and Price, R.M.} } @article {KNZ001964, title = {The freshwater biome gradient framework: predicting macroscale properties based on latitude, altitude, and precipitation}, journal = {Ecosphere}, volume = {10}, year = {2019}, pages = {e02786}, abstract = {

Understanding global ecological patterns and processes, from biogeochemical to biogeographical, requires broad-scale macrosystems context for comparing and contrasting ecosystems. Climate gradients (precipitation and temperature) and other continental-scale patterns shape freshwater environments due to their influences on terrestrial environments and their direct and indirect effects on the abiotic and biotic characteristics of lakes, streams, and wetlands. We combined literature review, analyses of open access data, and logical argument to assess abiotic and biotic characters of freshwater systems across gradients of latitude and elevation that drive precipitation, temperature, and other variability. We explored the predictive value of analyzing patterns in freshwater ecosystems at the global macrosystems scale. We found many patterns based on climate, particularly those dependent upon hydrologic characteristics and linked to characteristics of terrestrial biomes. For example, continental waters of dry areas will generally be widely dispersed and have higher probability of drying and network disconnection, greater temperatures, greater inorganic turbidity, greater salinity, and lower riparian canopy cover relative to areas with high precipitation. These factors will influence local community composition and ecosystem rates. Enough studies are now available at the continental or global scale to start to characterize patterns under a coherent conceptual framework, though considerable gaps exist in the tropics and less developed regions. We present illustrative global-scale trends of abiotic, biotic, and anthropogenic impacts in freshwater ecosystems across gradients of precipitation and temperature to further understanding of broad-scale trends and to aid prediction in the face of global change. We view freshwater systems as occurring across arrays of multiple gradients (including latitude, altitude, and precipitation) rather than areas with specific boundaries. While terrestrial biomes capture some variability along these gradients that influence freshwaters, other features such as, slope, geology, and historical glaciation also influence freshwaters. Our conceptual framework is not so much a single hypothesis as a way to logically characterize patterns in freshwaters at scales relevant to (1) evolutionary processes that give rise to freshwater biodiversity, (2) regulatory units that influence freshwater ecosystems, and (3) the current scope of anthropogenic impacts on freshwaters and the vital ecosystem services they provide.

}, keywords = {LTER-KNZ}, doi = {10.1002/ecs2.2786}, url = {https://onlinelibrary.wiley.com/toc/21508925/10/7}, author = {W. K. Dodds and Lindsey A. Bruckerhoff and Batzer, Darold and Schechner, Anne and Pennock, Casey and Renner, Elizabeth and Tromboni, Flavia and Bigham, Kari and Grieger, Samantha} } @article {KNZ001965, title = {Global change effects on plant communities are magnified by time and the number of global change factors imposed}, journal = {Proceedings of the National Academy of Sciences}, volume = {116}, year = {2019}, pages = {17867-17873}, abstract = {

Global change drivers (GCDs) are expected to alter community structure and consequently, the services that ecosystems provide. Yet, few experimental investigations have examined effects of GCDs on plant community structure across multiple ecosystem types, and those that do exist present conflicting patterns. In an unprecedented global synthesis of over 100 experiments that manipulated factors linked to GCDs, we show that herbaceous plant community responses depend on experimental manipulation length and number of factors manipulated. We found that plant communities are fairly resistant to experimentally manipulated GCDs in the short term (\<10 y). In contrast, long-term (\≥10 y) experiments show increasing community divergence of treatments from control conditions. Surprisingly, these community responses occurred with similar frequency across the GCD types manipulated in our database. However, community responses were more common when 3 or more GCDs were simultaneously manipulated, suggesting the emergence of additive or synergistic effects of multiple drivers, particularly over long time periods. In half of the cases, GCD manipulations caused a difference in community composition without a corresponding species richness difference, indicating that species reordering or replacement is an important mechanism of community responses to GCDs and should be given greater consideration when examining consequences of GCDs for the biodiversity\–ecosystem function relationship. Human activities are currently driving unparalleled global changes worldwide. Our analyses provide the most comprehensive evidence to date that these human activities may have widespread impacts on plant community composition globally, which will increase in frequency over time and be greater in areas where communities face multiple GCDs simultaneously.

}, keywords = {LTER-KNZ}, doi = {10.1073/pnas.1819027116}, url = {https://www.pnas.org/content/early/2019/08/14/1819027116}, author = {Kimberly J. Komatsu and M.L. Avolio and Lemoine, Nathan P. and Isbell, Forest and Grman, Emily and Houseman, Gregory R. and Koerner, Sally E. and Johnson, D.S. and K.R. Wilcox and Juha M. Alatalo and Anderson, J.P. and Aerts, R. and S.G. Baer and Baldwin, Andrew H. and Bates, J. and Beierkuhnlein, C. and Belote, R.T. and John M. Blair and Bloor, J.M.G. and Bohlen, P.J. and Edward W. Bork and Elizabeth H. Boughton and W.D. Bowman and Britton, Andrea J. and Cahill, James F. and Chaneton, Enrique J. and Chiariello, N.R. and Cheng, Jimin. and Scott. L. Collins and Cornelissen, J.H.C. and G. Du and Eskelinen, Anu and Firn, Jennifer and Foster, B. and Gough, L. and Gross, K. and Hallett, L.M. and Han, X. and Harmens, H. and Hovenden, M.J. and Jagerbrand, A. and Jentsch, A. and Kern, Christel and Klanderud, Kari and Alan K. Knapp and Kreyling, Juergen and Li, W. and Luo, Yiqi and McCulley, R.L. and McLaren, Jennie R. and Megonigal, Patrick and J.W. Morgan and Onipchenko, Vladimir and Pennings, S.C. and Prev{\'e}y, J.S. and Price, Jodi N. and P.B. Reich and Robinson, Clare H. and Russell, L.F. and Sala, O.E. and Seabloom, E.W. and M.D. Smith and Soudzilovskaia, Nadejda A. and Souza, Lara and K.N. Suding and Suttle, B.K. and Svejcar, T. and Tilman, David and Tognetti, P. and Turkington, R. and White, S. and Xu, Zhuwen and Yahdjian, L. and Yu, Q. and Zhang, Pengfei and Zhang, Yunhai} } @article {KNZ001933, title = {Global patterns and drivers of ecosystem functioning in rivers and riparian zones}, journal = {Science Advances}, volume = {5}, year = {2019}, pages = {eaav0486}, abstract = {

River ecosystems receive and process vast quantities of terrestrial organic carbon, the fate of which depends strongly on microbial activity. Variation in and controls of processing rates, however, are poorly characterized at the global scale. In response, we used a peer-sourced research network and a highly standardized carbon processing assay to conduct a global-scale field experiment in greater than 1000 river and riparian sites. We found that Earth\’s biomes have distinct carbon processing signatures. Slow processing is evident across latitudes, whereas rapid rates are restricted to lower latitudes. Both the mean rate and variability decline with latitude, suggesting temperature constraints toward the poles and greater roles for other environmental drivers (e.g., nutrient loading) toward the equator. These results and data set the stage for unprecedented \“next-generation biomonitoring\” by establishing baselines to help quantify environmental impacts to the functioning of ecosystems at a global scale.

}, keywords = {LTER-KNZ}, doi = {10.1126/sciadv.aav0486}, url = {http://advances.sciencemag.org/content/5/1/eaav0486}, author = {Tiegs, Scott D. and Costello, David M. and Isken, Mark W. and Woodward, Guy and McIntyre, Peter B. and Gessner, Mark O. and Chauvet, Eric and Griffiths, Natalie A. and Flecker, Alex S. and Acu{\~n}a, Vicenc and Albari{\~n}o, Ricardo and Allen, Daniel C. and Alonso, Cecilia and Andino, Patricio and Arango, Clay and Aroviita, Jukka and Barbosa, Marcus V. M. and Barmuta, Leon A. and Baxter, Colden V. and Bell, Thomas D. C. and Bellinger, Brent and Boyero, Luz and Brown, Lee E. and Bruder, Andreas and Bruesewitz, Denise A. and Burdon, Francis J. and Callisto, Marcos and Canhoto, Cristina and Capps, Krista A. and Castillo, Mar{\'\i}a M. and Clapcott, Joanne and Colas, Fanny and Col{\'o}n-Gaud, Checo and Cornut, Julien and Crespo-P{\'e}rez, Ver{\'o}nica and Cross, Wyatt F. and Culp, Joseph M. and Danger, Michael and Dangles, Olivier and de Eyto, Elvira and Derry, Alison M. and Villanueva, {\'\i}az and Douglas, Michael M. and Elosegi, Arturo and Encalada, Andrea C. and Entrekin, Sally and Espinosa, Rodrigo and Ethaiya, Diana and Ferreira, Ver{\'o}nica and Ferriol, Carmen and Flanagan, Kyla M. and Fleituch, Tadeusz and Follstad Shah, Jennifer J. and Frainer Barbosa, Andr{\'e} and Friberg, Nikolai and Frost, Paul C. and Garcia, Erica A. and Garc{\'\i}a Lago, Liliana and Garc{\'\i}a Soto, Pavel Ernesto and Ghate, Sudeep and Giling, Darren P. and Gilmer, Alan and {\c c}alves, Jos{\'e} Francisco and Gonzales, Rosario Karina and Graca, Manuel A. S. and Grace, Mike and Grossart, Hans-Peter and Guerrold, Francois and Gulis, Vlad and Hepp, Luiz U. and Higgins, Scott and Hishi, Takuo and Huddart, Joseph and Hudson, John and Imberger, Samantha and {\~n}iguez-Armijos, Carlos and Iwata, Tomoya and Janetski, David J. and Jennings, Eleanor and Kirkwood, Andrea E. and Koning, Aaron A. and Kosten, Sarian and Kuehn, Kevin A. and Laudon, Hjalmar and Leavitt, Peter R. and Lemes da Silva, Aurea L. and Leroux, Shawn J. and LeRoy, Carri J. and Lisi, Peter J. and MacKenzie, Richard and Marcarelli, Amy M. and Masese, Frank O. and McKie, Brendan G. and Oliveira Medeiros, Adriana and Meissner, Kristian and Mili{\v s}a, Marko and Mishra, Shailendra and Miyake, Yo and Moerke, Ashley and Mombrikotb, Shorok and Mooney, Rob and Moulton, Tim and Muotka, Timo and Negishi, Junjiro N. and Neres-Lima, Vinicius and Nieminen, Mika L. and Nimptsch, Jorge and Ondruch, Jakub and Paavola, Riku and Pardo, Isabel and Patrick, Christopher J. and Peeters, Edwin T. H. M. and Pozo, Jesus and Pringle, Catherine and Prussian, Aaron and Quenta, Estefania and Quesada, Antonio and Reid, Brian and Richardson, John S. and Rigosi, Anna and Rinc{\'o}n, Jos{\'e} and Risnoveanu, Geta and Robinson, Christopher T. and Rodr{\'\i}guez-Gallego, Lorena and Royer, Todd V. and Rusak, James A. and Santamans, Anna C. and Selmeczy, G{\'e}za B. and Simiyu, Gelas and Skuja, Agnija and Smykla, Jerzy and Sridhar, Kandikere R. and Sponseller, Ryan and Stoler, Aaron and Swan, Christopher M. and Szlag, David and Mello, Franco Teixeira-de and Tonkin, Jonathan D. and Uusheimo, Sari and Veach, Allison M. and Vilbaste, Sirje and Vought, Lena B. M. and Wang, Chiao-Ping and Webster, Jackson R. and Wilson, Paul B. and Woelfl, Stefan and Xenopoulos, Marguerite A. and Yates, Adam G. and Yoshimura, Chihiro and Yule, Catherine M. and Zhang, Yixin X. and Zwart, Jacob A.} } @article {KNZ001970, title = {How ecologists define drought, and why we should do better}, journal = {Global Change Biology}, volume = {25}, year = {2019}, pages = {3193 - 3200}, abstract = {

Drought, widely studied as an important driver of ecosystem dynamics, is predicted to increase in frequency and severity globally. To study drought, ecologists must define or at least operationalize what constitutes a drought. How this is accomplished in practice is unclear, particularly given that climatologists have long struggled to agree on definitions of drought, beyond general variants of \“an abnormal deficiency of water.\” We conducted a literature review of ecological drought studies (564 papers) to assess how ecologists describe and study drought. We found that ecologists characterize drought in a wide variety of ways (reduced precipitation, low soil moisture, reduced streamflow, etc.), but relatively few publications (~32\%) explicitly define what are, and are not, drought conditions. More troubling, a surprising number of papers (~30\%) simply equated \“dry conditions\” with \“drought\” and provided little characterization of the drought conditions studied. For a subset of these, we calculated Standardized Precipitation Evapotranspiration Index values for the reported drought periods. We found that while almost 90\% of the studies were conducted under conditions quantifiable as slightly to extremely drier than average, ~50\% were within the range of normal climatic variability. We conclude that the current state of the ecological drought literature hinders synthesis and our ability to draw broad ecological inferences because drought is often declared but is not explicitly defined or well characterized. We suggest that future drought publications provide at least one of the following: (a) the climatic context of the drought period based on long-term records; (b) standardized climatic index values; (c) published metrics from drought-monitoring organizations; (d) a quantitative definition of what the authors consider to be drought conditions for their system. With more detailed and consistent quantification of drought conditions, comparisons among studies can be more rigorous, increasing our understanding of the ecological effects of drought.

}, keywords = {LTER-KNZ}, doi = {10.1111/gcb.14747}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.14747}, author = {Slette, Ingrid J. and Post, Alison K. and Awad, Mai and Even, Trevor and Punzalan, Arianna and Williams, Sere and M.D. Smith and Alan K. Knapp} } @article {KNZ001972, title = {Local adaptation, genetic divergence, and experimental selection in a foundation grass across the US Great Plains{\textquoteright} climate gradient}, journal = {Global Change Biology}, volume = {25}, year = {2019}, pages = {850 - 868}, abstract = {

Many prior studies have uncovered evidence for local adaptation using reciprocal transplant experiments. However, these studies are rarely conducted for a long enough time to observe succession and competitive dynamics in a community context, limiting inferences for long-lived species. Furthermore, the genetic basis of local adaptation and genetic associations with climate has rarely been identified. Here, we report on a long-term (6-year) experiment conducted under natural conditions focused on Andropogon gerardii, the dominant grass of the North American Great Plains tallgrass ecosystem. We focus on this foundation grass that comprises 80\% of tallgrass prairie biomass and is widely used in 20,000 km2 of restoration. Specifically, we asked the following questions: (a) Whether ecotypes are locally adapted to regional climate in realistic ecological communities. (b) Does adaptive genetic variation underpin divergent phenotypes across the climate gradient? (c) Is there evidence of local adaptation if the plants are exposed to competition among ecotypes in mixed ecotype plots? Finally, (d) are local adaptation and genetic divergence related to climate? Reciprocal gardens were planted with 3 regional ecotypes (originating from dry, mesic, wet climate sources) of Andropogon gerardii across a precipitation gradient (500-1,200 mm/year) in the US Great Plains. We demonstrate local adaptation and differentiation of ecotypes in wet and dry environments. Surprisingly, the apparent generalist mesic ecotype performed comparably under all rainfall conditions. Ecotype performance was underpinned by differences in neutral diversity and candidate genes corroborating strong differences among ecotypes. Ecotype differentiation was related to climate, primarily rainfall. Without long-term studies, wrong conclusions would have been reached based on the first two years. Further, restoring prairies with climate-matched ecotypes is critical to future ecology, conservation, and sustainability under climate change.

}, keywords = {LTER-KNZ}, doi = {10.1111/gcb.14534}, url = {http://doi.wiley.com/10.1111/gcb.14534}, author = {Galliart, Matthew and Bello, Nora and Knapp, Mary and Poland, Jesse and St Amand, Paul and S.G. Baer and Maricle, Brian and Smith, Adam B. and Johnson, Loretta} } @article {KNZ001973, title = {Long-term biomass and potential ethanol yields of annual and perennial biofuel crops}, journal = {Agronomy Journal}, volume = {111}, year = {2019}, pages = {74 - 83}, abstract = {

Although energy crops could eventually supply a growing portion of cellulosic biofuel feedstocks, long-term comparisons of annual and perennial crops are rare. An experiment was established in 2007 near Manhattan, KS, to compare biomass productivity and ethanol yield of perennial and annual crops. Perennial crops included three C4 grasses: switchgrass (Panicum virgatum L.), big bluestem (Andropogon gerardii Vitman), and miscanthus (Miscanthus sacchariflorus). Annual C4 crops were corn (Zea mays L.) in two rotations: continuous and rotated with soybean [Glycine max (L.) Merr.]; and five types of sorghum [Sorghum bicolor (L.) Moench]: photoperiod sensitive, sweet, dual purpose (grain and biomass), brown mid-rib, and grain; all rotated with soybean. Annual crops produced 7 Mg ha\–1 yr\–1 more biomass than perennial crops throughout 11 yr, with sweet sorghum exceeding 22 Mg ha\–1 yr\–1, and 12 m3 ha\–1 yr\–1 of ethanol. Biomass yield of miscanthus approached 14 Mg ha\–1 yr\–1, essentially the same as for several annual crops but with half as much fertilizer nitrogen. Annual ethanol production from miscanthus and switchgrass was 3.6 m3 ha\–1 yr\–1, half as much as that of several annual crops that produced similar biomass yields. Big bluestem consistently produced the least biomass and ethanol, less than 7 Mg ha\–1 yr\–1 and 1.7 m3 ha\–1 yr\–1, respectively. Rotated corn averaged 7.1 m3 ha\–1 yr\–1 of ethanol. Eleven years of results indicate that annual corn and sorghum crops as well as perennial grasses such as miscanthus and switchgrass could play a role as potential bioenergy feedstocks in diversified production systems.

}, keywords = {LTER-KNZ}, doi = {0.2134/agronj2018.03.0172}, url = {http://doi.wiley.com/10.2134/agronj2018.03.0172}, author = {Roozeboom, Kraig L. and Wang, Donghai and McGowan, Andrew R. and Propheter, Jonathan L. and Staggenborg, Scott A. and C. W. Rice} } @article {KNZ001978, title = {Nutrients, eutrophication and harmful algal blooms along the freshwater to marine continuum}, journal = {WIRES Water}, volume = {6}, year = {2019}, pages = {e1373}, abstract = {

Agricultural, urban and industrial activities have dramatically increased aquatic nitrogen and phosphorus pollution (eutrophication), threatening water quality and biotic integrity from headwater streams to coastal areas world-wide. Eutrophication creates multiple problems, including hypoxic \“dead zones\” that reduce fish and shellfish production; harmful algal blooms that create taste and odor problems and threaten the safety of drinking water and aquatic food supplies; stimulation of greenhouse gas releases; and degradation of cultural and social values of these waters. Conservative estimates of annual costs of eutrophication have indicated $1 billion losses for European coastal waters and $2.4 billion for lakes and streams in the United States. Scientists have debated whether phosphorus, nitrogen, or both need to be reduced to control eutrophication along the freshwater to marine continuum, but many management agencies worldwide are increasingly opting for dual control. The unidirectional flow of water and nutrients through streams, rivers, lakes, estuaries and ultimately coastal oceans adds additional complexity, as each of these ecosystems may be limited by different factors. Consequently, the reduction of just one nutrient upstream to control eutrophication can allow the export of other nutrients downstream where they may stimulate algal production. The technology exists for controlling eutrophication, but many challenges remain for understanding and managing this global environmental problem.

}, keywords = {LTER-KNZ}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/wat2.1373}, author = {Wurtsbaugh, Wayne A. and Paerl, Hans W. and W. K. Dodds} } @article {KNZ001985, title = {Soil net nitrogen mineralisation across global grasslands}, journal = {Nature Communications}, volume = {10}, year = {2019}, abstract = {

Soil nitrogen mineralisation (Nmin), the conversion of organic into inorganic N, is important for productivity and nutrient cycling. The balance between mineralisation and immobilisation (net Nmin) varies with soil properties and climate. However, because most global-scale assessments of net Nmin are laboratory-based, its regulation under field-conditions and implications for real-world soil functioning remain uncertain. Here, we explore the drivers of realised (field) and potential (laboratory) soil net Nmin across 30 grasslands worldwide. We find that realised Nmin is largely explained by temperature of the wettest quarter, microbial biomass, clay content and bulk density. Potential Nmin only weakly correlates with realised Nmin, but contributes to explain realised net Nmin when combined with soil and climatic variables. We provide novel insights of global realised soil net Nmin and show that potential soil net Nmin data available in the literature could be parameterised with soil and climate data to better predict realised Nmin.

}, keywords = {LTER-KNZ}, doi = {10.1038/s41467-019-12948-2}, url = {http://www.nature.com/articles/s41467-019-12948-2}, author = {Risch, A.C. and Zimmermann, S. and Ochoa-Hueso, R. and sch{\"u}tz, M. and Frey, B. and Firn, J. L. and Fay, P. A. and Hagedorn, F. and E.T. Borer and Seabloom, E. W. and Harpole, W. S. and Knops, J. M. H. and McCulley, R. L. and Broadbent, A. A. D. and Stevens, C. J. and Silveira, M. L. and P. Adler and B{\'a}ez, S. and L.A. Biederman and John M. Blair and Brown, C. S. and Caldeira, M. C. and Scott. L. Collins and Daleo, P. and di Virgilio, A. and Ebeling, A. and Eisenhauer, N. and Esch, E. and Eskelinen, A. and Hagenah, N. and Hautier, Y. and Kirkman, K. P. and MacDougall, A. S. and Joslin L. Moore and Power, S. A. and Prober, S. M. and Roscher, C. and Sankaran, M. and Siebert, J. and Speziale, K. L. and Tognetti, P. M. and Virtanen, R. and Yahdjian, L. and Moser, B.} } @article {KNZ001863, title = {Asymmetric responses of primary productivity to altered precipitation simulated by ecosystem models across three long-term grassland sites}, journal = {Biogeosciences}, volume = {15}, year = {2018}, pages = {3421 - 3437}, abstract = {

Field measurements of aboveground net primary productivity (ANPP) in temperate grasslands suggest that both positive and negative asymmetric responses to changes in precipitation (P) may occur. Under normal range of precipitation variability, wet years typically result in ANPP gains being larger than ANPP declines in dry years (positive asymmetry), whereas increases in ANPP are lower in magnitude in extreme wet years compared to reductions during extreme drought (negative asymmetry). Whether the current generation of ecosystem models with a coupled carbon\–water system in grasslands are capable of simulating these asymmetric ANPP responses is an unresolved question. In this study, we evaluated the simulated responses of temperate grassland primary productivity to scenarios of altered precipitation with 14 ecosystem models at three sites: Shortgrass steppe (SGS), Konza Prairie (KNZ) and Stubai Valley meadow (STU), spanning a rainfall gradient from dry to moist. We found that (1)\ the spatial slopes derived from modeled primary productivity and precipitation across sites were steeper than the temporal slopes obtained from inter-annual variations, which was consistent with empirical data; (2)\ the asymmetry of the responses of modeled primary productivity under normal inter-annual precipitation variability differed among models, and the mean of the model ensemble suggested a negative asymmetry across the three sites, which was contrary to empirical evidence based on filed observations; (3)\ the mean sensitivity of modeled productivity to rainfall suggested greater negative response with reduced precipitation than positive response to an increased precipitation under extreme conditions at the three sites; and (4)\ gross primary productivity (GPP), net primary productivity (NPP), aboveground NPP (ANPP) and belowground NPP (BNPP) all showed concave-down nonlinear responses to altered precipitation in all the models, but with different curvatures and mean values. Our results indicated that most models overestimate the negative drought effects and/or underestimate the positive effects of increased precipitation on primary productivity under normal climate conditions, highlighting the need for improving eco-hydrological processes in those models in the future.

}, keywords = {LTER-KNZ}, doi = {10.5194/bg-15-3421-2018}, url = {https://www.biogeosciences.net/15/3421/2018/}, author = {Wu, Donghai and Ciais, Philippe and Viovy, Nicolas and Alan K. Knapp and K.R. Wilcox and Michael Bahn and M.D. Smith and Vicca, Sara and Fatichi, Simone and Zscheischler, Jakob and He, Yue and Li, Xiangyi and Ito, Akihiko and Arneth, Almut and Harper, Anna and Ukkola, Anna and Paschalis, Athanasios and Poulter, Benjamin and Peng, Changhui and Ricciuto, Daniel and Reinthaler, David and Chen, Guangsheng and Tian, Hanqin and Genet, {\'e}l{\`e}ne and Mao, Jiafu and Ingrisch, Johannes and Nabel, Julia E. S. M. and Pongratz, Julia and Lena R. Boysen and Kautz, Markus and Schmitt, Michael and Meir, Patrick and Zhu, Qiuan and R. Hasibeder and Sippel, Sebastian and Dangal, Shree R. S. and Sitch, Stephen and Shi, Xiaoying and Wang, Yingping and Luo, Yiqi and Liu, Yongwen and Piao, Shilong} } @article {KNZ001888, title = {Change in dominance determines herbivore effects on plant biodiversity}, journal = {Nature Ecology and Evolution}, volume = {2}, year = {2018}, pages = {1925-1932}, abstract = {

Herbivores alter plant biodiversity (species richness) in many of the world\’s ecosystems, but the magnitude and the direction of herbivore effects on biodiversity vary widely within and among ecosystems. One current theory predicts that herbivores enhance plant biodiversity at high productivity but have the opposite effect at low productivity. Yet, empirical support for the importance of site productivity as a mediator of these herbivore impacts is equivocal. Here, we synthesize data from 252 large-herbivore exclusion studies, spanning a 20-fold range in site productivity, to test an alternative hypothesis\—that herbivore-induced changes in the competitive environment determine the response of plant biodiversity to herbivory irrespective of productivity. Under this hypothesis, when herbivores reduce the abundance (biomass, cover) of dominant species (for example, because the dominant plant is palatable), additional resources become available to support new species, thereby increasing biodiversity. By contrast, if herbivores promote high dominance by increasing the abundance of herbivory-resistant, unpalatable species, then resource availability for other species decreases reducing biodiversity. We show that herbivore-induced change in dominance, independent of site productivity or precipitation (a proxy for productivity), is the best predictor of herbivore effects on biodiversity in grassland and savannah sites. Given that most herbaceous ecosystems are dominated by one or a few species, altering the competitive environment via herbivores or by other means may be an effective strategy for conserving biodiversity in grasslands and savannahs globally.

}, keywords = {LTER-KNZ}, doi = {https://doi.org/10.1038/s41559-018-0696-y}, url = {https://www.nature.com/articles/s41559-018-0696-y$\#$article-info}, author = {Koerner, S.E. and M.D. Smith and Burkepile, D.E. and N.P. Hanan and M.L. Avolio and Scott. L. Collins and Alan K. Knapp and N.P. Lemoine and E.J. Forrestel and S. Eby and D.I. Thompson and G. Aguado-Santacruz and J.P. Anderson and Anderson, M. and A. Angassa and S. Bagchi and E.S. Bakker and Bastin, Gary and L.E. Baur and K.H. Beard and E.A. Beever and P.J. Bohlen and Elizabeth H. Boughton and Canestro, Don and Cesa, Ariela and Chaneton, Enrique and Cheng, Jimin and C.M. D{\textquoteright}Antonio and C. Deleglise and Fadiala. Demb{\'e}l{\'e} and Josh. Dorrough and David. J. Eldridge and Barbara. Fernandez-Going and Silvia. Fern{\'a}ndez-Lugo and Lauchlan. H. Fraser and Bill. Freedman and Gonzalo. Garc{\'\i}a-Salgado and Jacob. R. Goheen and Liang. Guo and Sean. Husheer and Moussa. Karemb{\'e} and Johannes. M. H. Knops and Tineke. Kraaij and Andrew. Kulmatiski and Minna-Maarit. Kyt{\"o}viita and Felipe. Lezama and Gregory. Loucougaray and Alejandro. Loydi, Dan G. Milchunas, and Dan.G. Milchunas, and Suzanne. J. Milton and J.W. Morgan and Claire. Moxham and Kyle. C. Nehring and Han. Olff and Todd. M. Palmer and Salvador. Rebollo and Corinna. Riginos and Anita. C. Risch and Marta Rueda and Mahesh. Sankaran and Takehiro. Sasaki and Kathryn. A. Schoenecker and Nick. L. Schultz and Martin. Sch{\"u}tz and Angelika. Schwabe and Frances. Siebert and Christian. Smit and Karen. A. Stahlheber and Christian. Storm and Dustin. J. Strong and Jishuai. Su and Yadugiri. V. Tiruvaimozhi and Claudia. Tyler and James. Val and Martijn. L. Vandegehuchte and Kari. E. Veblen and Lance. T. Vermeire and David. Ward and Jianshuang. Wu and Truman. P. Young and Qiang. Yu and Tamara. Jane. Zelikova} } @article {KNZ001918, title = {Continental-scale decrease in net primary productivity in streams due to climate warming}, journal = {Nature Geoscience}, volume = {11}, year = {2018}, pages = {415 - 420}, abstract = {

Streams play a key role in the global carbon cycle. The balance between carbon intake through photosynthesis and carbon release via respiration influences carbon emissions from streams and depends on temperature. However, the lack of a comprehensive analysis of the temperature sensitivity of the metabolic balance in inland waters across latitudes and local climate conditions hinders an accurate projection of carbon emissions in a warmer future. Here, we use a model of diel dissolved oxygen dynamics, combined with high-frequency measurements of dissolved oxygen, light and temperature, to estimate the temperature sensitivities of gross primary production and ecosystem respiration in streams across six biomes, from the tropics to the arctic tundra. We find that the change in metabolic balance, that is, the ratio of gross primary production to ecosystem respiration, is a function of stream temperature and current metabolic balance. Applying this relationship to the global compilation of stream metabolism data, we find that a 1\ \°C increase in stream temperature leads to a convergence of metabolic balance and to a 23.6\% overall decline in net ecosystem productivity across the streams studied. We suggest that if the relationship holds for similarly sized streams around the globe, the warming-induced shifts in metabolic balance will result in an increase of 0.0194\ Pg carbon emitted from such streams every year.

}, keywords = {LTER-KNZ}, doi = {10.1038/s41561-018-0125-5}, url = {http://www.nature.com/articles/s41561-018-0125-5}, author = {Song, Chao and W. K. Dodds and R{\"u}egg, Janine and Argerich, Alba and Baker, Christina L. and W.B. Bowden and Douglas, Michael M. and Farrell, Kaitlin J. and Flinn, Michael B. and Garcia, Erica A. and Helton, Ashley M. and Harms, Tamara K. and Jia, Shufang and Jones, Jeremy B. and Koenig, Lauren E. and Kominoski, John S. and McDowell, William H. and McMaster, Damien and Parker, Samuel P. and Rosemond, Amy D. and Ruffing, Claire M. and Sheehan, Ken R. and Trentman, Matt T. and M.R. Whiles and Wollheim, Wilfred M. and Ballantyne, Ford} } @article {KNZ001886, title = {Drought consistently alters the composition of soil fungal and bacterial communities in grasslands from two continents}, journal = {Global Change Biology}, volume = {24}, year = {2018}, pages = {2818 - 2827}, abstract = {

The effects of short-term drought on soil microbial communities remain largely unexplored, particularly at large scales and under field conditions. We used seven experimental sites from two continents (North America and Australia) to evaluate the impacts of imposed extreme drought on the abundance, community composition, richness, and function of soil bacterial and fungal communities. The sites encompassed different grassland ecosystems spanning a wide range of climatic and soil properties. Drought significantly altered the community composition of soil bacteria and, to a lesser extent, fungi in grasslands from two continents. The magnitude of the fungal community change was directly proportional to the precipitation gradient. This greater fungal sensitivity to drought at more mesic sites contrasts with the generally observed pattern of greater drought sensitivity of plant communities in more arid grasslands, suggesting that plant and microbial communities may respond differently along precipitation gradients. Actinobateria, and Chloroflexi, bacterial phyla typically dominant in dry environments, increased their relative abundance in response to drought, whereas Glomeromycetes, a fungal class regarded as widely symbiotic, decreased in relative abundance. The response of Chlamydiae and Tenericutes, two phyla of mostly pathogenic species, decreased and increased along the precipitation gradient, respectively. Soil enzyme activity consistently increased under drought, a response that was attributed to drought-induced changes in microbial community structure rather than to changes in abundance and diversity. Our results provide evidence that drought has a widespread effect on the assembly of microbial communities, one of the major drivers of soil function in terrestrial ecosystems. Such responses may have important implications for the provision of key ecosystem services, including nutrient cycling, and may result in the weakening of plant\–microbial interactions and a greater incidence of certain soil-borne diseases.

}, keywords = {LTER-KNZ}, doi = {10.1111/gcb.2018.24.issue-710.1111/gcb.14113}, url = {http://doi.wiley.com/10.1111/gcb.2018.24.issue-7}, author = {Ochoa-Hueso, Ra{\'u}l and Scott. L. Collins and Delgado-Baquerizo, Manuel and Hamonts, Kelly and Pockman, William T. and Sinsabaugh, Robert L. and M.D. Smith and Alan K. Knapp and Power, Sally A.} } @article {KNZ001917, title = {Effects of frequency of protein supplementation on performance by beef calves grazing dormant native range}, journal = {Kansas Agricultural Experiment Station Research Reports}, volume = {4}, year = {2018}, abstract = {

Stocker calves that graze forages before entering a feedlot account for more than 75\% of the beef calves raised
in the United States each year. A large proportion of those will be calves born in the spring and weaned in the
fall. Modest growth rates are expected when the quality of fall and winter forages is poor. Growing calves in
confinement systems during fall and winter typically allows for greater average daily gain (ADG) than grazing
low-quality forages; however, modest overall costs associated with grazing perennial, dormant forages may be
competitive during times when feed prices are relatively high.
Providing supplemental protein to beef cows grazing dormant, warm-season, native forages (i.e., = 6\% crude
protein [CP]) has been demonstrated to increase body condition score (BCS), body weight (BW), improve
dry matter digestibility (DMD), and forage dry matter intake (DMI). Furthermore, beef cows grazing lowquality
forages and supplemented with protein either daily, every third day, or every sixth day had similar BW
and BCS.
Reducing the frequency of supplement delivery can reduce labor costs and equipment depreciation without
negatively affecting animal performance; however, this practice has variable success when used with growing
beef cattle. In previous research, steers supplemented with cottonseed cake 3 times weekly had similar BW
gain during winter compared to steers supplemented daily. Conversely, in another study, steers grazing winter
range and supplemented with dried distillers grain daily had greater ADG than steers supplemented 3 times
weekly. Therefore, the objective of this study was to evaluate the performance of young, lightweight stocker
calves grazing dormant, native tallgrass pastures and supplemented protein either daily or 3 times weekly
throughout the winter.

}, keywords = {LTER-KNZ, beef calves, pasture, protein, supplementation frequency}, doi = {10.4148/2378-5977.7555}, author = {Preedy, G. W. and Jaeger, J. R. and Waggoner, J. W. and K.C. Olson} } @article {KNZ001906, title = {Evolutionary history of plant hosts and fungal symbionts predicts the strength of mycorrhizal mutualism}, journal = {Communications Biology}, volume = {116}, year = {2018}, abstract = {

Most plants engage in symbioses with mycorrhizal fungi in soils and net consequences for plants vary widely from mutualism to parasitism. However, we lack a synthetic understanding of the evolutionary and ecological forces driving such variation for this or any other nutritional symbiosis. We used meta-analysis across 646 combinations of plants and fungi to show that evolutionary history explains substantially more variation in plant responses to mycorrhizal fungi than the ecological factors included in this study, such as nutrient fertilization and additional microbes. Evolutionary history also has a different influence on outcomes of ectomycorrhizal versus arbuscular mycorrhizal symbioses; the former are best explained by the multiple evolutionary origins of ectomycorrhizal lifestyle in plants, while the latter are best explained by recent diversification in plants; both are also explained by evolution of specificity between plants and fungi. These results provide the foundation for a synthetic framework to predict the outcomes of nutritional mutualisms.

}, keywords = {LTER-KNZ}, doi = {10.1038/s42003-018-0120-9}, url = {http://www.nature.com/articles/s42003-018-0120-9}, author = {Hoeksema, Jason D. and Bever, James D. and Chakraborty, Sounak and Chaudhary, V. Bala and Gardes, Monique and Gehring, Catherine A. and Hart, Miranda M. and Housworth, Elizabeth Ann and Kaonongbua, Wittaya and Klironomos, John N. and Lajeunesse, Marc J. and Meadow, James and Milligan, Brook G. and Piculell, Bridget J. and Pringle, Anne and R{\'u}a, Megan A. and Umbanhowar, James and Viechtbauer, Wolfgang and Wang, Yen-Wen and G.T. Wilson and Zee, Peter C.} } @article {KNZ001862, title = {Fine-scale movement and habitat use of a prairie stream fish assemblage}, journal = {Oecologia}, volume = {186}, year = {2018}, pages = {831{\textendash}842}, abstract = {

Measuring an organism\&$\#$39;s movement and habitat use is highly dependent on the spatial and temporal scale of the study, with most studies measuring distributions once a day or at less frequent intervals. Yet, to fully understand the rates of intra- and interspecific encounters among individuals, observations at finer spatial and temporal scales might be necessary. We used passive integrated transponder tags and antenna arrays to continuously monitor habitat use and vagility of three stream minnows; southern redbelly dace Chrosomus erythrogaster, central stoneroller Campostoma anomalum, and creek chub Semotilus atromaculatus, among and within pools of an intermittent stream. Most fish remained in the pool where they were caught and released, or returned after emigrating from the pool. Despite largely remaining within the release pool, distribution among four microhabitats differed significantly over six, 4-h time periods for all three species. Vagility, the summed distance moved among antennas, differed significantly among species. Individual vagility (m day-1) increased significantly with body length for stoneroller and chub, but not dace. Some individuals moved as much as 110 m day-1 within the pool, showcasing extensive movement at fine scales. Finally, we found no evidence that feeding activity changed as a result of differential habitat use over a 24-h period. Our findings indicate considerable variation in habitat use and movement occurs among species over a 24-h period. This suggests ecologists can broaden the interpretation of processes influencing community structure (e.g., resource partitioning, avoidance of predators) by quantifying species distributions across a range of spatial and temporal scales.

}, keywords = {LTER-KNZ}, doi = {10.1007/s00442-018-4073-y}, url = {https://link.springer.com/article/10.1007\%2Fs00442-018-4073-y}, author = {Pennock, C.A. and Nathan Cathcart, C. and Hedden, Skyler C. and Weber, Robert E. and K. B. Gido} } @article {KNZ001894, title = {Local loss and spatial homogenization of plant diversity reduce ecosystem multifunctionality}, journal = {Nature Ecology \& Evolution}, volume = {2}, year = {2018}, pages = {50-56}, abstract = {

Biodiversity is declining in many local communities while also becoming increasingly homogenized across space. Experiments show that local plant species loss reduces ecosystem functioning and services, but the role of spatial homogenization of community composition and the potential interaction between diversity at different scales in maintaining ecosystem functioning remains unclear, especially when many functions are considered (ecosystem multifunctionality). We present an analysis of eight ecosystem functions measured in 65 grasslands worldwide. We find that more diverse grasslands\—those with both species-rich local communities (α-diversity) and large compositional differences among localities (β-diversity)\—had higher levels of multifunctionality. Moreover, α- and β-diversity synergistically affected multifunctionality, with higher levels of diversity at one scale amplifying the contribution to ecological functions at the other scale. The identity of species influencing ecosystem functioning differed among functions and across local communities, explaining why more diverse grasslands maintained greater functionality when more functions and localities were considered. These results were robust to variation in environmental drivers. Our findings reveal that plant diversity, at both local and landscape scales, contributes to the maintenance of multiple ecosystem services provided by grasslands. Preserving ecosystem functioning therefore requires conservation of biodiversity both within and among ecological communities.

}, keywords = {LTER-KNZ}, doi = {10.1038/s41559-017-0395-0}, url = {http://www.nature.com/articles/s41559-017-0395-0}, author = {Hautier, Yann and Isbell, Forest and E.T. Borer and Seabloom, Eric W. and Harpole, W. Stanley and Lind, Eric M. and MacDougall, Andrew S. and Stevens, Carly J. and P. Adler and J. Alberti and Bakker, Jonathan D. and Brudvig, Lars A. and Buckley, Yvonne M. and Cadotte, Marc and Caldeira, Maria C. and Chaneton, Enrique J. and Chu, Chengjin and Daleo, Pedro and Dickman, Christopher R. and Dwyer, John M. and Eskelinen, Anu and Fay, Philip A. and Firn, Jennifer and Hagenah, Nicole and Hillebrand, Helmut and Iribarne, Oscar and Kirkman, Kevin P. and Knops, Johannes M. H. and Kimberly J. La Pierre and McCulley, Rebecca L. and J.W. Morgan and P{\"a}rtel, Meelis and Pascual, Jesus and Price, Jodi N. and Prober, Suzanne M. and Risch, Anita C. and Sankaran, Mahesh and Schuetz, Martin and Standish, Rachel J. and Virtanen, Risto and Wardle, Glenda M. and Yahdjian, Laura and Hector, Andy} } @article {KNZ001936, title = {Long- and short-term responses of Asclepias species differ in respect to fire, grazing, and nutrient addition}, journal = {American Journal of Botany}, volume = {105}, year = {2018}, pages = {2008-2017}, abstract = {

PREMISE OF THE STUDY: The tallgrass prairie ecosystem has experienced a dramatic reduction over the past 150 yr. This reduction has impacted the abundance of native grassland species, including milkweeds (Asclepias).


METHODS: We used two long-term (27 yr) data sets to examine how fire, grazing, and nutrient addition shape milkweed abundance in tallgrass prairie. We compared these results to those of a greenhouse experiment that varied nutrient levels in the absence of competition, herbivory, and mutualistic relationships.


KEY RESULTS: Asclepias species exhibited broad patterns in response to burning regimes that did not include grazing, but experienced more species-specific patterns in other combinations. Asclepias syriaca was the only species to increase in abundance in plots that included burning and nutrient addition. In the greenhouse we found that nitrogen significantly increased biomass, while no effect of phosphorus was detected.


CONCLUSIONS: These results indicate that A. syriaca will do best in settings with high nutrient loads, low competition, and no grazers. These characteristics define a small portion of the tallgrass prairie but exemplify modern agricultural settings, which have replaced prairies. However, other milkweeds examined did not share this pattern, which indicates that milkweed species will respond differently when exposed to agricultural settings, with some less able to cope with land conversion to pasture or row-crop agriculture.

}, keywords = {LTER-KNZ}, doi = {10.1002/ajb2.2018.105.issue-1210.1002/ajb2.1197}, url = {https://bsapubs.onlinelibrary.wiley.com/doi/full/10.1002/ajb2.1197}, author = {Ricono, A. and Dixon, R. and Eaton, I. and Brightbill, C.M. and Yaziji, Y. and Puzey, J.R. and Dalgleish, H.J.} } @article {KNZ001891, title = {Microbial community structure and functional potential in cultivated and native tallgrass prairie soils of the midwestern united states}, journal = {Frontiers in Microbiology}, volume = {9}, year = {2018}, pages = {1775}, abstract = {

The North American prairie covered about 3.6 million-km2 of the continent prior to European contact. Only 1\–2\% of the original prairie remains, but the soils that developed under these prairies are some of the most productive and fertile in the world, containing over 35\% of the soil carbon in the continental United States. Cultivation may alter microbial diversity and composition, influencing the metabolism of carbon, nitrogen, and other elements. Here, we explored the structure and functional potential of the soil microbiome in paired cultivated-corn (at the time of sampling) and never-cultivated native prairie soils across a three-states transect (Wisconsin, Iowa, and Kansas) using metagenomic and 16S rRNA gene sequencing and lipid analysis. At the Wisconsin site, we also sampled adjacent restored prairie and switchgrass plots. We found that agricultural practices drove differences in community composition and diversity across the transect. Microbial biomass in prairie samples was twice that of cultivated soils, but alpha diversity was higher with cultivation. Metagenome analyses revealed denitrification and starch degradation genes were abundant across all soils, as were core genes involved in response to osmotic stress, resource transport, and environmental sensing. Together, these data indicate that cultivation shifted the microbiome in consistent ways across different regions of the prairie, but also suggest that many functions are resilient to changes caused by land management practices \– perhaps reflecting adaptations to conditions common to tallgrass prairie soils in the region (e.g., soil type, parent material, development under grasses, temperature and rainfall patterns, and annual freeze-thaw cycles). These findings are important for understanding the long-term consequences of land management practices to prairie soil microbial communities and their genetic potential to carry out key functions.

}, keywords = {LTER-KNZ, carbon cycle, Climate change, Land management, metagenomics, native prairie, nitrogen cycle, soil microbiome}, doi = {10.3389/fmicb.2018.01775}, url = {https://www.frontiersin.org/articles/10.3389/fmicb.2018.01775}, author = {Mackelprang, Rachel and Grube, Alyssa M. and Lamendella, Regina and Jesus, Ederson da C. and Copeland, Alex and Liang, Chao and Jackson, Randall D. and C. W. Rice and Kapucija, Stefanie and Parsa, Bayan and Tringe, Susannah G. and Tiedje, James M. and Jansson, Janet K.} } @article {KNZ001902, title = {Mycorrhizal symbioses influence the trophic structure of the Serengeti}, journal = {Journal of Ecology}, volume = {106}, year = {2018}, pages = {536 - 546}, abstract = {
  1. It is known that tropical grasslands such as Serengeti host large populations of arbuscular mycorrhizal (AM) fungi and that they respond to abiotic and biotic factors. It is also known that AM symbioses are important for the uptake of essential plant nutrients, which, in turn, influences the biomass and nutritional quality of herbivores and their predators. The purpose of this study was to investigate the influence of AM symbioses on the biomass of different trophic levels of an ecosystem.
  2. To do this, we first measured the neutral lipid fatty acid biomarker 16:1ω5 to estimate the biomass of AM fungi in a long-term grazing exclusion experiment. Then, we used model selection of Bayesian linear regressions to infer the primary factors that influence AM fungal biomass. Using model selection of different combinations of soil characteristics, we selected the best model using the leave-one-out cross-validation information criterion. Finally, we used the Madingley model to simulate the influence of AM fungi on higher trophic levels. We combined spatially explicit information about soil phosphorus and AM fungal biomass to explore the emergent patterns of the Serengeti resulting from AM symbioses.
  3. Our Bayesian analysis indicated that total soil phosphorus was the strongest predictor of AM fungal biomass, and there were significant interactions with grazing. Arbuscular mycorrhizal fungal biomass is lowest in soil where phosphorus is limited and increases with increasing phosphorus concentration. Biomass was also significantly higher in plots that were not grazed. The Madingley model indicated that nutritional benefits of AM symbioses maintain a substantial proportion of the biomass across all trophic levels.
  4. Synthesis. Our analysis shows that inputs of phosphorus through arbuscular mycorrhizal symbioses substantially increase the ability of plants to grow and maintain nutritional quality, cascading through the biomass of consumers and predators in the ecosystem. Although they account for less than 1\% of the total modelled biomass, the predicted nutritional benefit provided by arbuscular mycorrhizal fungi increased the biomass of macro-organisms in the Serengeti by 48\%. When considering the management of biodiversity, future ecosystem models should account for the influence of arbuscular mycorrhizal fungi on all trophic levels.

}, keywords = {LTER-KNZ}, doi = {10.1111/1365-2745.12916}, url = {http://doi.wiley.com/10.1111/1365-2745.12916}, author = {Stevens, Bo Maxwell and Propster, Jeffrey and G.T. Wilson and Abraham, Andrew and Ridenour, Chase and Doughty, Christopher and Johnson, Nancy Collins}, editor = {Wurzburger, Nina} } @article {KNZ001887, title = {A reality check for climate change experiments: Do they reflect the real world?}, journal = {Ecology}, volume = {99}, year = {2018}, pages = {2145-2151}, abstract = {

Experiments are widely used in ecology, particularly for assessing global change impacts on ecosystem function. However, results from experiments often are inconsistent with observations made under natural conditions, suggesting the need for rigorous comparisons of experimental and observational studies. We conducted such a \“reality check\” for a grassland ecosystem by compiling results from nine independently conducted climate change experiments. Each experiment manipulated growing season precipitation (GSP) and measured responses in aboveground net primary production (ANPP). We compared results from experiments with long-term (33-yr) annual precipitation and ANPP records to ask if collectively (n\ =\ 44 experiment-years) experiments yielded estimates of ANPP, rain-use efficiency (RUE, grams per square meter ANPP per mm precipitation), and the relationship between GSP and ANPP comparable to observations. We found that mean ANPP and RUE from experiments did not deviate from observations. Experiments and observational data also yielded similar functional relationships between ANPP and GSP, but only within the range of historically observed GSP. Fewer experiments imposed extreme levels of GSP (outside the observed 33-yr record), but when these were included, they altered the GSP\–ANPP relationship. This result underscores the need for more experiments imposing extreme precipitation levels to resolve how forecast changes in climate regimes will affect ecosystem function in the future.

}, keywords = {LTER-KNZ}, doi = {10.1002/ecy.2474}, url = {https://esajournals.onlinelibrary.wiley.com/doi/epdf/10.1002/ecy.2474}, author = {Alan K. Knapp and Carroll, C.J.W. and Griffin-Nolan, R.J. and Slette, I.J. and Chavez, F.A. and Baur, L. and Felton, A.J. and Gray, J. and Hoffman, A.M. and Lemoine, N.P. and Mao, W. and Post, A. and M.D. Smith} } @article {KNZ001884, title = {Regional grassland productivity responses to precipitation during multiyear above- and below-average rainfall periods}, journal = {Global Change Biology}, volume = {24}, year = {2018}, pages = {1935 - 1951}, abstract = {

There is considerable uncertainty in the magnitude and direction of changes in precipitation associated with climate change, and ecosystem responses are also uncertain. Multiyear periods of above- and below-average rainfall may foretell consequences of changes in rainfall regime. We compiled long-term aboveground net primary productivity (ANPP) and precipitation (PPT) data for eight North American grasslands, and quantified relationships between ANPP and PPT at each site, and in 1-3\ year periods of above- and below-average rainfall for mesic, semiarid cool, and semiarid warm grassland types. Our objective was to improve understanding of ANPP dynamics associated with changing climatic conditions by contrasting PPT-ANPP relationships in above- and below-average PPT years to those that occurred during sequences of multiple above- and below-average years. We found differences in PPT-ANPP relationships in above- and below-average years compared to long-term site averages, and variation in ANPP not explained by PPT totals that likely are attributed to legacy effects. The correlation between ANPP and current- and prior-year conditions changed from year to year throughout multiyear periods, with some legacy effects declining, and new responses emerging. Thus, ANPP in a given year was influenced by sequences of conditions that varied across grassland types and climates. Most importantly, the influence of prior-year ANPP often increased with the length of multiyear periods, whereas the influence of the amount of current-year PPT declined. Although the mechanisms by which a directional change in the frequency of above- and below-average years imposes a persistent change in grassland ANPP require further investigation, our results emphasize the importance of legacy effects on productivity for sequences of above- vs. below-average years, and illustrate the utility of long-term data to examine these patterns.

}, keywords = {LTER-KNZ}, doi = {10.1111/gcb.2018.24.issue-510.1111/gcb.14024}, url = {https://www.ncbi.nlm.nih.gov/pubmed/29265568}, author = {Petrie, Matthew D. and Peters, Debra P. C. and Yao, Jin and John M. Blair and Burruss, Nathan D. and Scott. L. Collins and Derner, Justin D. and Gherardi, Laureano A. and Hendrickson, John R. and Sala, Osvaldo E. and Starks, Patrick J. and Steiner, Jean L.} } @article {KNZ001864, title = {Similarity of stream width distributions across headwater systems}, journal = {Nature Communications}, volume = {9}, year = {2018}, chapter = {610}, abstract = {

The morphology and abundance of streams control the rates of hydraulic and biogeochemical exchange between streams, groundwater, and the atmosphere. In large river systems, the relationship between river width and abundance is fractal, such that narrow rivers are proportionally more common than wider rivers. However, in headwater systems, where many biogeochemical reactions are most rapid, the relationship between stream width and abundance is unknown. To constrain this uncertainty, we surveyed stream hydromorphology (wetted width and length) in several headwater stream networks across North America and New Zealand. Here, we find a strikingly consistent lognormal statistical distribution of stream width, including a characteristic most abundant stream width of 32\ \±\ 7\ cm independent of discharge or physiographic conditions. We propose a hydromorphic model that can be used to more accurately estimate the hydromorphology of streams, with significant impact on the understanding of the hydraulic, ecological, and biogeochemical functions of stream networks.

}, keywords = {LTER-KNZ}, doi = {10.1038/s41467-018-02991-w}, url = {https://www.nature.com/articles/s41467-018-02991-w}, author = {Allen, George H. and Pavelsky, Tamlin M. and Barefoot, Eric A. and Lamb, Michael P. and Butman, David and Tashie, Arik and Gleason, Colin J.} } @article {KNZ001882, title = {Spatial heterogeneity in species composition constrains plant community responses to herbivory and fertilisation}, journal = {Ecology Letters}, volume = {21}, year = {2018}, pages = {1364 -1371}, abstract = {

Environmental change can result in substantial shifts in community composition. The associated immigration and extinction events are likely constrained by the spatial distribution of species. Still, studies on environmental change typically quantify biotic responses at single spatial (time series within a single plot) or temporal (spatial beta diversity at single time points) scales, ignoring their potential interdependence. Here, we use data from a global network of grassland experiments to determine how turnover responses to two major forms of environmental change \– fertilisation and herbivore loss \– are affected by species pool size and spatial compositional heterogeneity. Fertilisation led to higher rates of local extinction, whereas turnover in herbivore exclusion plots was driven by species replacement. Overall, sites with more spatially heterogeneous composition showed significantly higher rates of annual turnover, independent of species pool size and treatment. Taking into account spatial biodiversity aspects will therefore improve our understanding of consequences of global and anthropogenic change on community dynamics.

}, keywords = {LTER-KNZ}, doi = {10.1111/ele.13102}, url = {https://onlinelibrary.wiley.com/doi/pdf/10.1111/ele.13102}, author = {Hodapp, Dorothee and E.T. Borer and Harpole, W. Stanley and Lind, Eric M. and Seabloom, Eric W. and P. Adler and J. Alberti and Arnillas, Carlos A. and J.D. Bakker and L.A. Biederman and Cadotte, Marc and Cleland, Elsa E. and Scott. L. Collins and Fay, Philip A. and Firn, Jennifer and Hagenah, Nicole and Hautier, Yann and Iribarne, Oscar and Knops, Johannes M. H. and McCulley, Rebecca L. and MacDougall, Andrew and Joslin L. Moore and J.W. Morgan and Mortensen, Brent and Kimberly J. La Pierre and Risch, Anita C. and Sch{\"u}tz, Martin and Peri, Pablo and Stevens, Carly J. and Wright, Justin and Hillebrand, Helmut}, editor = {Gurevitch, Jessica} } @article {KNZ001883, title = {Trait selection and community weighting are key to understanding ecosystem responses to changing precipitation regimes}, journal = {Functional Ecology}, volume = {32}, year = {2018}, pages = {1746 - 1756}, abstract = {

1. Plant traits can be used to predict ecosystem responses to environmental change using a response\–effect trait framework. To do this, appropriate traits must be identified that explain a species\&$\#$39; influence on ecosystem function (\“effect traits\”) and the response of those species to environmental change (\“response traits\”). Response traits are often identified and measured along gradients in plant resources, such as water availability; however, precipitation explains very little variation in most plant traits globally. Given the strong relationship between plant traits and ecosystem functions, such as net primary productivity (NPP), and between NPP and precipitation, the lack of correlation between precipitation and plant traits is surprising.

2. We address this issue through a systematic review of \>500 published studies that describe plant trait responses to altered water availability. The overarching goal of this review was to identify potential causes for the weak relationship between commonly measured plant traits and water availability so that we may identify more appropriate \“response traits.\”

3. We attribute weak trait\–precipitation relationships to an improper selection of traits (e.g., nonhydraulic traits) and a lack of trait-based approaches that adjust for trait variation within communities (only 4\% of studies measure community-weighted traits). We then highlight the mechanistic value of hydraulic traits as more appropriate \“response traits\” with regard to precipitation, which should be included in future community-scale trait surveys.

4. Trait-based ecology has the potential to improve predictions of ecosystem responses to predicted changes in precipitation; however, this predictive power depends heavily on the identification of reliable response and effect traits. To this end, trait surveys could be improved by a selection of traits that reflect physiological functions directly related to water availability with traits weighted by species relative abundance.

}, keywords = {LTER-KNZ}, doi = {10.1111/1365-2435.13135}, url = {https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2435.13135}, author = {Griffin-Nolan, Robert J. and Bushey, Julie A. and Carroll, Charles J. W. and Challis, Anthea and Chieppa, Jeff and Garbowski, Magda and Hoffman, Ava M. and Post, Alison K. and Slette, Ingrid J. and Spitzer, Daniel and Zambonini, Dario and Ocheltree, Troy W. and Tissue, David T. and Alan K. Knapp}, editor = {Fox, Charles} } @article {KNZ001852, title = {Assessing community and ecosystem sensitivity to climate change - toward a more comparative approach}, journal = {Journal of Vegetation Science}, volume = {28}, year = {2017}, pages = {235 - 237}, abstract = {

Plant communities can vary widely in their sensitivity to changing precipitation regimes, as reported by Byrne et al., Mulhouse et al. and Sternberg et al. in this issue of Journal of Vegetation Science. But to understand why communities differ in their sensitivity, we argue that clearly defined metrics of sensitivity and coordinated research approaches are needed to elucidate mechanisms.

}, keywords = {LTER-KNZ}, doi = {10.1111/jvs.12524}, url = {https://onlinelibrary.wiley.com/doi/full/10.1111/jvs.12524}, author = {M.D. Smith and K.R. Wilcox and Power, Sally A. and Tissue, David T. and Alan K. Knapp} } @article {KNZ001811, title = {Asymmetric responses of primary productivity to precipitation extremes: A synthesis of grassland precipitation manipulation experiments}, journal = {Global Change Biology}, volume = {23}, year = {2017}, month = {4376-4385}, abstract = {

Climatic changes are altering Earth\&$\#$39;s hydrological cycle, resulting in altered precipitation amounts, increased interannual variability of precipitation, and more frequent extreme precipitation events. These trends will likely continue into the future, having substantial impacts on net primary productivity (NPP) and associated ecosystem services such as food production and carbon sequestration. Frequently, experimental manipulations of precipitation have linked altered precipitation regimes to changes in NPP. Yet, findings have been diverse and substantial uncertainty still surrounds generalities describing patterns of ecosystem sensitivity to altered precipitation. Additionally, we do not know whether previously observed correlations between NPP and precipitation remain accurate when precipitation changes become extreme. We synthesized results from 83 case studies of experimental precipitation manipulations in grasslands worldwide. We used meta-analytical techniques to search for generalities and asymmetries of aboveground NPP (ANPP) and belowground NPP (BNPP) responses to both the direction and magnitude of precipitation change. Sensitivity (i.e., productivity response standardized by the amount of precipitation change) of BNPP was similar under precipitation additions and reductions, but ANPP was more sensitive to precipitation additions than reductions; this was especially evident in drier ecosystems. Additionally, overall relationships between the magnitude of productivity responses and the magnitude of precipitation change were saturating in form. The saturating form of this relationship was likely driven by ANPP responses to very extreme precipitation increases, although there were limited studies imposing extreme precipitation change, and there was considerable variation among experiments. This highlights the importance of incorporating gradients of manipulations, ranging from extreme drought to extreme precipitation increases into future climate change experiments. Additionally, policy and land management decisions related to global change scenarios should consider how ANPP and BNPP responses may differ, and that ecosystem responses to extreme events might not be predicted from relationships found under moderate environmental changes.

}, keywords = {LTER-KNZ}, doi = {10.1111/gcb.13706}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.13706}, author = {K.R. Wilcox and Shi, Zheng and Gherardi, Laureano A. and Lemoine, Nathan P. and Koerner, Sally E. and Hoover, David L. and Bork, Edward and Byrne, Kerry M. and Cahill, James and Scott. L. Collins and Evans, Sarah and Gilgen, Anna K. and Holub, Petr and Jiang, Lifen and Alan K. Knapp and LeCain, Daniel and Liang, Junyi and Garcia-Palacios, Pablo and Pe{\~n}uelas, Josep and Pockman, William T. and M.D. Smith and Sun, Shanghua and White, Shannon R. and Yahdjian, Laura and Zhu, Kai and Luo, Yiqi} } @article {KNZ001842, title = {Asynchrony among local communities stabilises ecosystem function of metacommunities}, journal = {Ecology Letters}, year = {2017}, abstract = {

Temporal stability of ecosystem functioning increases the predictability and reliability of ecosystem services, and understanding the drivers of stability across spatial scales is important for land management and policy decisions. We used species-level abundance data from 62 plant communities across five continents to assess mechanisms of temporal stability across spatial scales. We assessed how asynchrony (i.e. different units responding dissimilarly through time) of species and local communities stabilised metacommunity ecosystem function. Asynchrony of species increased stability of local communities, and asynchrony among local communities enhanced metacommunity stability by a wide range of magnitudes (1\–315\%); this range was positively correlated with the size of the metacommunity. Additionally, asynchronous responses among local communities were linked with species\’ populations fluctuating asynchronously across space, perhaps stemming from physical and/or competitive differences among local communities. Accordingly, we suggest spatial heterogeneity should be a major focus for maintaining the stability of ecosystem services at larger spatial scales.

}, keywords = {LTER-KNZ, Alpha diversity, alpha variability, beta diversity, Biodiversity, CoRRE data base, patchiness, Plant communities, Primary productivity, species synchrony}, doi = {10.1111/ele.12861}, url = {http://onlinelibrary.wiley.com/doi/10.1111/ele.12861/epdf}, author = {K.R. Wilcox and Tredennick, Andrew T. and Koerner, Sally E. and Grman, Emily and Hallett, Lauren M. and M.L. Avolio and Kimberly J. La Pierre and Houseman, Gregory R. and Isbell, Forest and Johnson, David Samuel and Juha M. Alatalo and Baldwin, Andrew H. and Edward W. Bork and Elizabeth H. Boughton and W.D. Bowman and Britton, Andrea J. and Cahill, James F. and Scott. L. Collins and G. Du and Eskelinen, Anu and Gough, Laura and Jentsch, Anke and Kern, Christel and Klanderud, Kari and Alan K. Knapp and Kreyling, Juergen and Luo, Yiqi and McLaren, Jennie R. and Megonigal, Patrick and Onipchenko, Vladimir and Prev{\'e}y, Janet and Price, Jodi N. and Robinson, Clare H. and Sala, Osvaldo E. and M.D. Smith and Soudzilovskaia, Nadejda A. and Souza, Lara and Tilman, David and White, Shannon R. and Xu, Zhuwen and Yahdjian, Laura and Yu, Qiang and Zhang, Pengfei and Zhang, Yunhai}, editor = {Gurevitch, Jessica} } @book {KNZ001829, title = {Biogeography of root-associated endophytes. In: Biogeography of Mycorrhizal Symbiosis}, volume = {230}, year = {2017}, pages = {195-222}, publisher = {Springer International Publishing}, organization = {Springer International Publishing}, address = {Cham}, abstract = {

Healthy plant roots usually host heterogeneous communities of root endophytes that are abundant in all plants and ecosystems. Despite their abundance, current understanding of the distribution of these endophytes is superficial at the best. A comprehensive treatise of the distribution of variety of fungi described as root endophytes would most likely prove an exhausting exercise in futility, given the large gaps in current data. As a result, we broadly target the helotialean endophytes that are commonly observed in temperate and boreal, forested ecosystems and the pleosporalean endophytes commonly observed in grassland ecosystems. To explore the sparse data available for the distribution of these root-associated fungal endophytes, we combine references from current literature and a case study to evaluate whether or not the endophyte communities (1) shift over environmental gradients, (2) respond to some specific drivers, or (3) seem limited by dispersal by showing distance-decay responses. The data indicate that communities of endophytic fungi indeed change over large geographical scales. The available data suggest a Helotiales-dominated endophyte guild in forested ecosystems and a Pleosporales-dominated assemblage in grassland ecosystems. Further, large-scale studies and our preliminary analyses of communities across North American grassland ecosystems suggest some shifts corresponding to geographical/environmental gradients. However, specific drivers are difficult to distinguish because abiotic gradients are often correlated, resulting in complex model selection problems. Finally, we observed that our own and published data reach no agreement on distance decay, even though both agree that the distance decay may be of rather minor importance.

}, keywords = {LTER-KNZ, Distance decay, Environmental filtering, Helotiales, Pleosporales}, doi = {10.1007/978-3-319-56363-3}, url = {https://link.springer.com/book/10.1007\%2F978-3-319-56363-3}, author = {A. Jumpponen and Herrera, J. and Porras-Alfaro, A. and Rudgers, J.} } @article {KNZ001725, title = {Density dependence of herbivorous central stoneroller Campostoma anomalum in stream mesocosms}, journal = {Ecology of Freshwater Fishes}, volume = {26}, year = {2017}, pages = {313-321}, abstract = {

Herbivorous fish can have strong effects on stream ecosystem function by consuming primary producers and excreting limiting nutrients, but it is unclear whether they are resource limited. Thus, understanding factors regulating abundance of these fish might help predict ecosystem function. We used stream mesocosms to test whether populations of central stoneroller Campostoma anomalum exhibit density dependence across a range of typical densities and resource abundance found in Great Plains streams. We predicted that incrementally increasing stocking biomass from 3\·7 to 24\·9\ g\·m\−2 would reduce standing stocks of resources resulting in lower growth of stocked fish. Fish growth (over 41\ days) was compared to initial stocking biomass and primary production as well as standing stocks of algae and invertebrates using regression analysis. Mean growth of individuals was negatively associated with stocking biomass (math formula\ =\ 0\·55; P\ =\ 0\·02), as predicted. Contrary to our prediction, increases in fish biomass led to increased primary productivity (math formula\ =\ 0\·31, P\ =\ 0\·07), but resulted in no relationship among algal filament lengths (math formula\ =\ 0\·00; P\ =\ 0\·34), algal biomass (math formula\ =\ 0\·12; P\ =\ 0\·19) or invertebrate biomass (math formula\ =\ 0\·03; P\ =\ 0\·30). Thus, density dependence occurred without an apparent reduction in food resources. We hypothesised that stoneroller growth was possibly limited by competition for high-quality algae or invertebrates, or behavioural interactions causing interference competition.

}, keywords = {LTER-KNZ, Herbivory, Primary production, Resource limitation, stream fish}, doi = {10.1111/eff.12277}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/eff.12277}, author = {Pennock, C.A. and K. B. Gido} } @article {KNZ001824, title = {Drivers of nitrogen transfer in stream food webs across continents}, journal = {Ecology}, volume = {98}, year = {2017}, pages = {3055}, chapter = {3044}, abstract = {

Studies of trophic-level material and energy transfers are central to ecology.\ The use of isotopic tracers has now made it possible to measure trophic transfer efficiencies of important nutrients and to better understand how these materials move through food webs.\ We analyzed data from thirteen\ 15N-ammonium tracer addition experiments to quantify N transfer from basal resources to animals in headwater streams with varying physical, chemical, and biological features. N transfer efficiencies from primary uptake compartments (PUCs; heterotrophic microorganisms and primary producers) to primary consumers was lower (mean 11.5\%, range \<1\% to 43\%) than N transfer efficiencies from primary consumers to predators (mean 80\%, range 5\% to \>100\%). Total N transferred (as a rate) was greater in streams with open compared to closed canopies and overall N transfer efficiency generally followed a similar pattern, although was not statistically significant. We used principal component analysis to condense a suite of site characteristics into two environmental components. Total N uptake rates among trophic levels were best predicted by the component that was correlated with latitude, DIN:SRP, GPP:ER, and percent canopy cover. N transfer efficiency did not respond consistently to environmental variables. Our results suggest that canopy cover influences N movement through stream food webs because light availability and primary production facilitate N transfer to higher trophic levels.

}, keywords = {LTER-KNZ}, doi = {10.1002/ecy.2009}, url = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1002/ecy.2009}, author = {Norman, B. C. and Whiles, M. R. and S. M. Collins and Flecker, A. S. and Hamilton, S. K. and Johnson, S. L. and Rosi-Marshall, E. J. and L.R. Ashkenas and W.B. Bowden and Crenshaw, C. L. and Crowl, T. and W. K. Dodds and Hall, R. O. and El-Sabaawi, R. and Griffiths, N. A. and Marti, E. and McDowell, W. H. and Peterson, S. D. and Rantala, H. M. and Riis, T. and Simon, K. S. and Tank, J. L. and Thomas, S. A. and von Schiller, D. and Webster, J. R.} } @article {KNZ001848, title = {Effects of rangeland management on survival of female greater prairie-chickens}, journal = {The Journal of Wildlife Management}, year = {2017}, abstract = {

Identifying relationships between habitat selection and population processes is important for habitat management and wildlife conservation. For prairie-obligate species, space use and demography in extant grasslands are influenced by habitat conditions caused by rangeland management practices associated with livestock production. Greater prairie-chickens (Tympanuchus cupido) are an indicator species for native tallgrass prairie ecosystems, but populations have declined in the Flint Hills ecoregion of eastern Kansas, USA because of intensification of rangeland management practices, including annual prescribed fire and high stocking densities. Patch-burn grazing is a rotational system that provides heterogeneous habitats and can improve productivity of grassland birds, but the effects of grazing systems on habitat use or survival of greater prairie-chickens are unknown. We used 3 types of survival analyses to investigate impacts of rangeland management on female greater prairie-chickens in the central Flint Hills during 2011\–2013: Kaplan\–Meier models and Cox proportional hazards to examine factors affecting annual survival rates, hazard functions to assess seasonal patterns of mortality, and Andersen\–Gill models to explore the links between habitat selection and cause-specific mortality risk. Females captured at properties managed with patch-burn grazing had annual survival rates (0.61\ \±\ 0.07\ SE) that were 35\% higher than females on properties managed with annual burning and intensive early cattle stocking (0.45\ \±\ 0.06). Moreover, females that selected habitats associated with intensive management had increased mortality risk and were particularly vulnerable to avian predators, whereas females that selected habitats created by patch-burn grazing experienced lower overall mortality risk but were more vulnerable to mammalian predators. Overall mortality risk was significantly reduced under patch-burn grazing management, and widespread implementation of annual spring burning and intensive early stocking is likely depressing survival of greater prairie-chickens in the Flint Hills ecoregion. Our results join a growing body of evidence that patch-burn grazing can provide higher quality grassland habitats for native wildlife species than current rangeland management associated with intensive cattle production. \© 2017 The Wildlife Society

}, keywords = {LTER-KNZ}, doi = {10.1002/jwmg.21331}, url = {https://wildlife.onlinelibrary.wiley.com/doi/abs/10.1002/jwmg.21331}, author = {Winder, Virginia L. and McNew, Lance B. and Pitman, James C. and Sandercock, B.K.} } @article {KNZ001870, title = {Groundwater declines are linked to changes in Great Plains stream fish assemblages}, journal = {Proceedings of the National Academy of Sciences}, volume = {114}, year = {2017}, pages = {7373 - 7378}, abstract = {

Groundwater pumping for agriculture is a major driver causing declines of global freshwater ecosystems, yet the ecological consequences for stream fish assemblages are rarely quantified. We combined retrospective (1950\–2010) and prospective (2011\–2060) modeling approaches within a multiscale framework to predict change in Great Plains stream fish assemblages associated with groundwater pumping from the United States High Plains Aquifer. We modeled the relationship between the length of stream receiving water from the High Plains Aquifer and the occurrence of fishes characteristic of small and large streams in the western Great Plains at a regional scale and for six subwatersheds nested within the region. Water development at the regional scale was associated with construction of 154 barriers that fragment stream habitats, increased depth to groundwater and loss of 558 km of stream, and transformation of fish assemblage structure from dominance by large-stream to small-stream fishes. Scaling down to subwatersheds revealed consistent transformations in fish assemblage structure among western subwatersheds with increasing depths to groundwater. Although transformations occurred in the absence of barriers, barriers along mainstem rivers isolate depauperate western fish assemblages from relatively intact eastern fish assemblages. Projections to 2060 indicate loss of an additional 286 km of stream across the region, as well as continued replacement of large-stream fishes by small-stream fishes where groundwater pumping has increased depth to groundwater. Our work illustrates the shrinking of streams and homogenization of Great Plains stream fish assemblages related to groundwater pumping, and we predict similar transformations worldwide where local and regional aquifer depletions occur.

}, keywords = {LTER-KNZ}, doi = {10.1073/pnas.1618936114}, url = {https://www.pnas.org/content/114/28/7373}, author = {Perkin, Joshuah S. and K. B. Gido and Falke, Jeffrey A. and Fausch, Kurt D. and Crockett, Harry and Johnson, Eric R. and Sanderson, John} } @article {KNZ001814, title = {How do extra nutrients affect the timing of flowering in prairies}, journal = {Environmental Science Journal for Teens}, year = {2017}, keywords = {LTER-KNZ}, url = {http://www.sciencejournalforkids.org/uploads/5/4/2/8/54289603/flowers_article.pdf}, author = {L.A. Biederman and Mortensen, Brent and Fay, P.A. and Hagenah, Nicole and Knops, Johannes and Kimberly J. La Pierre and Laungani, Ramesh and Lind, Eric and McCulley, Rebecca and Power, Sally and Seabloom, Eric and Tognetti, Pedro} } @article {KNZ001895, title = {Increased grassland arthropod production with mammalian herbivory and eutrophication: a test of mediation pathways}, journal = {Ecology}, volume = {98}, year = {2017}, pages = {3022-3033}, abstract = {

Increases in nutrient availability and alterations to mammalian herbivore communities are a hallmark of the Anthropocene, with consequences for the primary producer communities in many ecosystems. While progress has advanced understanding of plant community responses to these perturbations, the consequences for energy flow to higher trophic levels in the form of secondary production are less well understood. We quantified arthropod biomass after manipulating soil nutrient availability and wild mammalian herbivory, using identical methods across 13 temperate grasslands. Of experimental increases in nitrogen, phosphorus, and potassium, only treatments including nitrogen resulted in significantly increased arthropod biomass. Wild mammalian herbivore removal had a marginal, negative effect on arthropod biomass, with no interaction with nutrient availability. Path analysis including all sites implicated nutrient content of the primary producers as a driver of increased arthropod mean size, which we confirmed using 10 sites for which we had foliar nutrient data. Plant biomass and physical structure mediated the increase in arthropod abundance, while the nitrogen treatments accounted for additional variation not explained by our measured plant variables. The mean size of arthropod individuals was 2.5 times more influential on the plot-level total arthropod biomass than was the number of individuals. The eutrophication of grasslands through human activity, especially nitrogen deposition, thus may contribute to higher production of arthropod consumers through increases in nutrient availability across trophic levels.

}, keywords = {LTER-KNZ}, doi = {10.1002/ecy.2029}, url = {http://doi.wiley.com/10.1002/ecy.2029}, author = {Lind, Eric M. and Kimberly J. La Pierre and Seabloom, Eric W. and J. Alberti and Iribarne, Oscar and Firn, Jennifer and Gruner, Daniel S. and Kay, Adam D. and Pascal, Jesus and Wright, Justin P. and Yang, Louie and E.T. Borer} } @article {KNZ001868, title = {Nutrient addition shifts plant community composition towards earlier flowering species in some prairie ecoregions in the U.S. Central Plains}, journal = {PLOS ONE}, year = {2017}, pages = {e0178440}, abstract = {

The distribution of flowering across the growing season is governed by each species\’ evolutionary history and climatic variability. However, global change factors, such as eutrophication and invasion, can alter plant community composition and thus change the distribution of flowering across the growing season. We examined three ecoregions (tall-, mixed, and short-grass prairie) across the U.S. Central Plains to determine how nutrient (nitrogen (N), phosphorus, and potassium (+micronutrient)) addition alters the temporal patterns of plant flowering traits. We calculated total community flowering potential (FP) by distributing peak-season plant cover values across the growing season, allocating each species\’ cover to only those months in which it typically flowers. We also generated separate FP profiles for exotic and native species and functional group. We compared the ability of the added nutrients to shift the distribution of these FP profiles (total and sub-groups) across the growing season. In all ecoregions, N increased the relative cover of both exotic species and C3 graminoids that flower in May through August. The cover of C4 graminoids decreased with added N, but the response varied by ecoregion and month. However, these functional changes only aggregated to shift the entire community\’s FP profile in the tall-grass prairie, where the relative cover of plants expected to flower in May and June increased and those that flower in September and October decreased with added N. The relatively low native cover in May and June may leave this ecoregion vulnerable to disturbance-induced invasion by exotic species that occupy this temporal niche. There was no change in the FP profile of the mixed and short-grass prairies with N addition as increased abundance of exotic species and C3 graminoids replaced other species that flower at the same time. In these communities a disturbance other than nutrient addition may be required to disrupt phenological patterns.

}, keywords = {LTER-KNZ}, doi = {10.1371/journal.pone.0178440}, url = {http://dx.plos.org/10.1371/journal.pone.0178440ttp}, author = {L.A. Biederman and Mortensen, B. and Fay, P.A. and Hagenah, N. and Knops, J. and Kimberly J. La Pierre and Laungani, R. and Lind, E. and McCulley, R. and Power, S. and Seabloom, E. and Tognetti, P.} } @article {KNZ001893, title = {Out of the shadows: multiple nutrient limitations drive relationships among biomass, light and plant diversity}, journal = {Functional Ecology}, volume = {31}, year = {2017}, pages = {1839-1846}, abstract = {
  1. The paradigmatic hypothesis for the effect of fertilisation on plant diversity represents a one-dimensional trade-off for plants competing for below-ground nutrients (generically) and above-ground light: fertilisation reduces competition for nutrients while increasing biomass and thereby shifts competition for depleted available light.
  2. The essential problem of this simple paradigm is that it misses both the multivariate and mechanistic nature of the factors that determine biodiversity as well as their causal relationships.
  3. We agree that light limitation, as DeMalach and Kadmon argue, can indeed be an important factor associated with diversity loss, and we presented it as an integral part of our tests of the niche dimension hypothesis.
  4. We disagree with DeMalach and Kadmon that light is the \‘main\’ factor explaining diversity, because this misrepresents the causal structure represented in the design of our experiment in which multiple nutrient addition was the ultimate causal driver of a suite of correlated responses that included diversity and light, and especially live and dead biomass, which are the factors that control light depletion.
  5. Our findings highlight that multiple nutrient limitations can structure plant diversity and composition independently of changes in light and biomass. For example, approximately one-third of our sites showed no significant increase in biomass with greater number of added nutrients yet still lost diversity when nutrients were added.
  6. The important message is that while light limitation can be an important contributor to diversity loss, it is not a necessary mechanism.
}, keywords = {LTER-KNZ}, doi = {10.1111/1365-2435.12967}, url = {https://besjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1365-2435.12967}, author = {Harpole, W. Stanley and L.L. Sullivan and Lind, Eric M. and Firn, Jennifer and P. Adler and E.T. Borer and Chase, Jonathan and Fay, Philip A. and Hautier, Yann and Hillebrand, Helmut and MacDougall, Andrew S. and Seabloom, Eric W. and Bakker, Jonathan D. and Cadotte, Marc W. and Chaneton, Enrique J. and Chu, Chengjin and Hagenah, Nicole and Kirkman, Kevin and Kimberly J. La Pierre and Joslin L. Moore and J.W. Morgan and Prober, Suzanne M. and Risch, Anita C. and Schuetz, Martin and Stevens, Carly J.}, editor = {Thompson, Ken} } @article {KNZ001783, title = {Pushing precipitation to the extremes in distributed experiments: recommendations for simulating wet and dry years}, journal = {Global Change Biology}, volume = {23}, year = {2017}, pages = {1774-1782}, abstract = {

Intensification of the global hydrological cycle, ranging from larger individual precipitation events to more extreme multiyear droughts, has the potential to cause widespread alterations in ecosystem structure and function. With evidence that the incidence of extreme precipitation years (defined statistically from historical precipitation records) is increasing, there is a clear need to identify ecosystems that are most vulnerable to these changes and understand why some ecosystems are more sensitive to extremes than others. To date, opportunistic studies of naturally occurring extreme precipitation years, combined with results from a relatively small number of experiments, have provided limited mechanistic understanding of differences in ecosystem sensitivity, suggesting that new approaches are needed. Coordinated distributed experiments (CDEs) arrayed across multiple ecosystem types and focused on water can enhance our understanding of differential ecosystem sensitivity to precipitation extremes, but there are many design challenges to overcome (e.g., cost, comparability, standardization). Here, we evaluate contemporary experimental approaches for manipulating precipitation under field conditions to inform the design of \‘Drought-Net\’, a relatively low-cost CDE that simulates extreme precipitation years. A common method for imposing both dry and wet years is to alter each ambient precipitation event. We endorse this approach for imposing extreme precipitation years because it simultaneously alters other precipitation characteristics (i.e., event size) consistent with natural precipitation patterns. However, we do not advocate applying identical treatment levels at all sites \– a common approach to standardization in CDEs. This is because precipitation variability varies \>fivefold globally resulting in a wide range of ecosystem-specific thresholds for defining extreme precipitation years. For CDEs focused on precipitation extremes, treatments should be based on each site\&$\#$39;s past climatic characteristics. This approach, though not often used by ecologists, allows ecological responses to be directly compared across disparate ecosystems and climates, facilitating process-level understanding of ecosystem sensitivity to precipitation extremes.

}, keywords = {LTER-KNZ}, doi = {10.1111/gcb.13504}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.13504}, author = {Alan K. Knapp and M.L. Avolio and Beier, C. and Carroll, C.J.W. and Scott. L. Collins and Dukes, J.S. and Fraser, L.H. and Griffin-Nolan, R.J. and Hoover, D.L. and Jentsch, A. and Loik, M.E. and Phillips, R.P. and Post, A.K. and Sala, O.E. and Slette, I.J. and Yahdjian, L. and M.D. Smith} } @article {KNZ001807, title = {Space use of female greater Prairie-Chickens in response to fire and grazing interactions}, journal = {Rangeland Ecology \& Management}, volume = {70}, year = {2017}, pages = {165{\textendash}174}, abstract = {Ecological interactions between fire and grazing have shaped the evolutionary history of grassland ecosystems. Currently, grassland birds have experienced ongoing population declines, following widespread implementation of intensive rangeland management practices that reduce habitat heterogeneity. Patch-burn grazing is an alternative rangeland management strategy that promotes habitat heterogeneity and biodiversity. We conducted a 3-yr. field study in the central Flint Hills of Kansas to compare the spatial ecology of female Greater Prairie-Chickens (Tympanuchus cupido) in rangelands managed with intensive rangeland management versus patch-burn grazing. This is the first study on the effects of patch-burn grazing on the space use decisions of Greater Prairie-Chickens at the home range scale. We used seasonal estimates of home range for 6-mo breeding and nonbreeding periods, as well as resource utilization functions to investigate the response of female prairie chickens to landscape metrics describing fire, grazing, and proximity to anthropogenic structures or lek sites. In our analysis of all radio-marked females, distance to lek was consistently the strongest predictor of space use during both breeding and nonbreeding seasons. Females captured at properties managed with patch-burn grazing selected areas with low stocking rates and high fire frequencies, and they avoided recently burned areas. Our study provides new evidence that patch-burn grazing can improve grassland habitat for Greater Prairie-Chickens, an umbrella species in the tallgrass prairie ecosystem. Patch-burn grazing created preferred habitats for female Greater Prairie-Chickens, with a relatively frequent fire return interval, a mosaic of burned and unburned patches, and a reduced stocking rate in unburned areas avoided by grazers. Widespread implementation of patch-burn grazing could result in significant improvements in habitat quality for wildlife in the tallgrass prairie ecosystem.}, keywords = {LTER-KNZ, Home range, intensive early stocking, patch-burn grazing, prescribed fire, resource utilization function, Tympanuchus cupido}, doi = {10.1016/j.rama.2016.08.004}, url = {https://www.sciencedirect.com/science/article/pii/S1550742416300720?via\%3Dihub}, author = {Winder, Virginia L. and McNew, Lance B. and Pitman, Jim C. and Sandercock, B.K.} } @article {KNZ001755, title = {Addition of multiple limiting resources reduces grassland diversity}, journal = {Nature}, volume = {537}, year = {2016}, pages = {93-96}, abstract = {

Niche dimensionality provides a general theoretical explanation for biodiversity\—more niches, defined by more limiting factors, allow for more ways that species can coexist1. Because plant species compete for the same set of limiting resources, theory predicts that addition of a limiting resource eliminates potential trade-offs, reducing the number of species that can coexist2. Multiple nutrient limitation of plant production is common and therefore fertilization may reduce diversity by reducing the number or dimensionality of belowground limiting factors. At the same time, nutrient addition, by increasing biomass, should ultimately shift competition from belowground nutrients towards a one-dimensional competitive trade-off for light3. Here we show that plant species diversity decreased when a greater number of limiting nutrients were added across 45 grassland sites from a multi-continent experimental network4. The number of added nutrients predicted diversity loss, even after controlling for effects of plant biomass, and even where biomass production was not nutrient-limited. We found that elevated resource supply reduced niche dimensionality and diversity and increased both productivity5 and compositional turnover. Our results point to the importance of understanding dimensionality in ecological systems that are undergoing diversity loss in response to multiple global change factors.

}, keywords = {LTER-KNZ}, doi = {10.1038/nature19324}, url = {https://www.nature.com/articles/nature19324}, author = {Harpole, W. S. and L.L. Sullivan and Lind, E.M. and Firn, J. and P. Adler and E.T. Borer and Chase, J. and Fay, P.A. and Hautier, Y. and Hillebrand, H. and MacDougall, A.S. and Seabloom, E.W. and Williams, R. and J.D. Bakker and Cadotte, M.W. and Chaneton, E.J. and Chu, C. and Cleland, E.E. and Antonio, C. and Davies, K.F. and Gruner, D.S. and Hagenah, N. and Kirkman, K. and Knops, J.M.H. and Kimberly J. La Pierre and McCulley, R.L. and Joslin L. Moore and J.W. Morgan and Prober, S.M. and A. Risch and Schuetz, M. and Stevens, C.J. and Wragg, P.D.} } @article {KNZ001708, title = {Baseflow physical characteristics differ at multiple spatial scales in stream networks across diverse biomes}, journal = {Landscape Ecology}, volume = {31}, year = {2016}, pages = {119-136}, abstract = {

Context Spatial scaling of ecological processes is facilitated by quantifying underlying habitat attributes. Physical and ecological patterns are often measured at disparate spatial scales limiting our ability to quantify ecological processes at broader spatial scales using physical attributes. Objective We characterized variation of physical stream attributes during periods of high biological activity (i.e., baseflow) to match physical and ecological measurements and to identify the spatial scales exhibiting and predicting heterogeneity. Methods We measured canopy cover, wetted width, water depth, and sediment size along transects of 1st\–5th order reaches in five stream networks located in biomes from tropical forest to arctic tundra. We used hierarchical analysis of variance with three nested scales (watersheds, stream orders, reaches) to identify scales exhibiting significant heterogeneity in attributes and regression analyses to characterize gradients within and across stream networks. Results Heterogeneity was evident at one or multiple spatial scales: canopy cover and water depth varied significantly at all three spatial scales while wetted width varied at two scales (stream order and reach) and sediment size remained largely unexplained. Similarly, prediction by drainage area depended on the attribute considered: depending on the watershed, increases in wetted width and water depth with drainage area were best fit with a linear, logarithmic, or power function. Variation in sediment size was independent of drainage area. Conclusions The scaling of ecologically relevant baseflow physical characteristics will require study beyond the traditional bankfull geomorphology since predictions of baseflow physical attributes by drainage area were not always best explained by geomorphic power laws.

}, keywords = {LTER-KNZ, Boreal forest, Geomorphology, Grasslands, Nested ANOVA, Scaling, Temperate forest}, issn = {0921-2973}, doi = {10.1007/s10980-015-0289-y}, url = {https://link.springer.com/article/10.1007\%2Fs10980-015-0289-y}, author = {R{\"u}egg, Janine and W. K. Dodds and Daniels, M.D. and Sheehan, Ken R. and Baker, Christina L. and W.B. Bowden and Farrell, Kaitlin J. and Flinn, Michael B. and Harms, Tamara K. and Jones, J.B. and Koenig, Lauren E. and Kominoski, John S. and W.H. McDowell and Parker, Samuel P. and Rosemond, Amy D. and Trentman, Matt T. and M.R. Whiles and Wollheim, Wilfred M.} } @article {KNZ001770, title = {Belowground interactions with aboveground consequences: Invasive earthworms and arbuscular mycorrhizal fungi}, journal = {Ecology}, volume = {97}, year = {2016}, pages = {605 - 614}, abstract = {

A mounting body of research suggests that invasive nonnative earthworms substantially alter microbial communities, including arbuscular mycorrhizal fungi (AMF). These changes to AMF can cascade to affect plant communities and vertebrate populations. Despite these research advances, relatively little is known about (1) the mechanisms behind earthworms\’ effects on AMF and (2) the factors that determine the outcomes of earthworm\–AMF interactions (i.e., whether AMF abundance is increased or decreased and subsequent effects on plants). We predict that AMF-mediated effects of nonnative earthworms on ecosystems are nearly universal because (1) AMF are important components of most terrestrial ecosystems, (2) nonnative earthworms have become established in nearly every type of terrestrial ecosystem, and (3) nonnative earthworms, due to their burrowing and feeding behavior, greatly affect AMF with potentially profound concomitant effects on plant communities. We highlight the multiple direct and indirect effects of nonnative earthworms on plants and review what is currently known about the interaction between earthworms and AMF. We also illustrate how the effects of nonnative earthworms on plant\–AMF mutualisms can alter the structure and stability of aboveground plant communities, as well as the vertebrate communities relying on these habitats. Integrative studies that assess the interactive effects of earthworms and AMF can provide new insights into the role that belowground ecosystem engineers play in altering aboveground ecological processes. Understanding these processes may improve our ability to predict the structure of plant and animal communities in earthworm-invaded regions and to develop management strategies that limit the numerous undesired impacts of earthworms.

}, keywords = {LTER-KNZ}, doi = {10.1890/15-1085}, url = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/15-1085}, author = {Paudel, S. and Longcore, T. and MacDonald, B. and McCormick, M.K. and Szlavecz, K. and G.T. Wilson and Loss, S.R.} } @article {KNZ001746, title = {Beyond arctic and alpine: the influence of winter climate on temperate ecosystems}, journal = {Ecology}, volume = {97}, year = {2016}, pages = {372 - 382}, abstract = {

Winter climate is expected to change under future climate scenarios, yet the majority of winter ecology research is focused in cold-climate ecosystems. In many temperate systems, it is unclear how winter climate relates to biotic responses during the growing season. The objective of this study was to examine how winter weather relates to plant and animal communities in a variety of terrestrial ecosystems ranging from warm deserts to alpine tundra. Specifically, we examined the association between winter weather and plant phenology, plant species richness, consumer abundance, and consumer richness in 11 terrestrial ecosystems associated with the U.S. Long-Term Ecological Research (LTER) Network. To varying degrees, winter precipitation and temperature were correlated with all biotic response variables. Bud break was tightly aligned with end of winter temperatures. For half the sites, winter weather was a better predictor of plant species richness than growing season weather. Warmer winters were correlated with lower consumer abundances in both temperate and alpine systems. Our findings suggest winter weather may have a strong influence on biotic activity during the growing season and should be considered in future studies investigating the effects of climate change on both alpine and temperate systems.

}, keywords = {LTER-KNZ}, doi = {10.1890/15-0153.1}, url = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/15-0153.1}, author = {L. Ladwig and Z. Ratajczak and Ocheltree, T.W. and Hafich, K.A. and Churchill, A.C. and Frey, S.J.K. and Fuss, C.B. and Kazanski, C.E. and Mu{\~n}oz, J.D. and Petrie, M.D. and Reinmann, A.B. and Smith, J.G.} } @article {KNZ001774, title = {Characterizing organic matter inputs to sediments of small, intermittent, prairie streams: a molecular marker and stable isotope approach}, journal = {Aquatic Sciences}, volume = {78}, year = {2016}, pages = {343 - 354}, abstract = {

Small rivers and streams are ecologically important because they contribute to the export of organic carbon to coastal environments, likely influencing the global carbon cycle. While organic matter (OM) dynamics in large rivers has been studied in quite some detail, less is known about small streams. Sources of OM in streams ultimately determine its availability to the food web and downstream transport. In this study, sediment samples were collected from the King\’s Creek watershed in Konza Prairie (Kansas, USA) and analyzed using molecular biomarkers and bulk 13C stable isotopes with the objective to comparatively assess OM inputs between riparian forest vegetation and watershed grassland to small, intermittent streams. We are interested in the potential influence of woody riparian expansion that has been ongoing at the site. Biomarkers typical of the local C4 grasses (branched n-alkanes, phytadienes) were more abundant in some of the sediments of the upper reaches. The sediments of the lower reaches contained biomarkers of algae (short-chain aliphatic compounds, C25:5 highly branched isoprenoid, brassicasterol) and vascular plant-derived material (triterpenols). Degraded OM (triterpene/triterpenol ratio) was found throughout the watershed with no pattern between the upper and lower reaches. Bulk 13C isotope analysis showed that the upper reaches of the watershed receive significant OM inputs from the C4 grasses (74\–99 \%) while the lower reaches are more strongly influenced by riparian trees (26\–27 \%) and algae (21\–22 \%). These results suggest that the environmental dynamics of bulk OM and the biomarker composition of small prairie streams are highly complex and likely a function of several factors such as light availability, riparian vegetative composition and density, and varying degrees of OM storage, retention and transport along the river continuum.

}, keywords = {LTER-KNZ, 13C stable isotopes, Biomarkers, Konza Prairie, Riparian, Small streams, Watershed}, issn = {1015-1621}, doi = {10.1007/s00027-015-0435-2}, url = {https://link.springer.com/article/10.1007\%2Fs00027-015-0435-2}, author = {Pisani, O. and W. K. Dodds and Jaff{\'e}, R.} } @article {KNZ001747, title = {Climate modifies response of non-native and native species richness to nutrient enrichment}, journal = {Philosophical Transactions of the Royal Society B: Biological Sciences}, volume = {3719371}, year = {2016}, pages = {20150273}, abstract = {

Ecosystem eutrophication often increases domination by non-natives and causes displacement of native taxa. However, variation in environmental conditions may affect the outcome of interactions between native and non-native taxa in environments where nutrient supply is elevated. We examined the interactive effects of eutrophication, climate variability and climate average conditions on the success of native and non-native plant species using experimental nutrient manipulations replicated at 32 grassland sites on four continents. We hypothesized that effects of nutrient addition would be greatest where climate was stable and benign, owing to reduced niche partitioning. We found that the abundance of non-native species increased with nutrient addition independent of climate; however, nutrient addition increased non-native species richness and decreased native species richness, with these effects dampened in warmer or wetter sites. Eutrophication also altered the time scale in which grassland invasion responded to climate, decreasing the importance of long-term climate and increasing that of annual climate. Thus, climatic conditions mediate the responses of native and non-native flora to nutrient enrichment. Our results suggest that the negative effect of nutrient addition on native abundance is decoupled from its effect on richness, and reduces the time scale of the links between climate and compositional change.

}, keywords = {LTER-KNZ}, issn = {0962-8436}, doi = {10.1098/rstb.2015.0273}, url = {https://royalsocietypublishing.org/doi/10.1098/rstb.2015.0273}, author = {Flores-Moreno, H. and P.B. Reich and Lind, E.M. and L.L. Sullivan and Seabloom, E.W. and Yahdjian, L. and MacDougall, A.S. and Reichmann, L.G. and J. Alberti and B{\'a}ez, S. and J.D. Bakker and Cadotte, M.W. and Caldeira, M.C. and Chaneton, E.J. and D{\textquoteright}Antonio, C.M. and Fay, P.A. and Firn, J. and Hagenah, N. and Harpole, W. S. and Iribarne, O. and Kirkman, K.P. and Knops, J.M. H. and Kimberly J. La Pierre and Laungani, R. and Leakey, A.D. B. and McCulley, R.L. and Joslin L. Moore and Pascual, J. and E.T. Borer} } @article {KNZ001737, title = {Crab spiders (Thomisidae) attract insect flower-visitors without UV signaling}, journal = {Ecological Entomology}, volume = {41}, year = {2016}, pages = {611-617}, type = {Journal Articles}, abstract = {

1. Crab spiders (Thomisidae) indirectly affect insect flower-visitor and flowering plant interactions by consuming and altering the behaviour of insects. 2. Although one expects insect flower-visitors to avoid crab spiders actively, some crab spider species are known to attract flower-visitors. Crab spiders may use UV signalling to lure potential prey to the flowers they occupy. 3. In the present study, a field experiment was conducted to examine the effects of crab spiders occupying three prairie plant species for the insect flower-visitor community. Pollinating insects were significantly attracted to inflorescences with crab spiders compared to inflorescences without crab spiders for two plant species, and herbivorous insects were attracted to inflorescences with crab spiders for one of these plant species. The two flowering plant species with increased pollinator visitation showed increased seed weights for plants with crab spiders, indicating crab spider presence indirectly increased pollination. 4. To test the UV signalling hypothesis, inflorescences with crab spiders of one plant species were observed under both a UV-blocking plastic and a clear plastic control. Contrary to our prediction, flower-visitors were not more likely to land on inflorescences under the clear plastic; the UV signalling hypothesis was not supported. Other unknown explanations underlie prey attraction to inflorescences with crab spiders.

}, keywords = {LTER-KNZ}, doi = {10.1111/een.12334}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/een.12334}, author = {Welti, E. and Putnam, S. and Anthony Joern} } @phdthesis {KNZ001827, title = {The effects of P fertilizer addition on P transformations on high-P fixing and grassland soils}, volume = {PhD Dissertation}, year = {2016}, school = {Kansas State University}, type = {Ph.D. Thesis}, address = {Manhattan, KS}, abstract = {

Although phosphorus (P) is an essential nutrient for the growth of plants, it is one of the most limiting nutrients in terms of availability as a high proportion of applied P rapidly transforms into insoluble forms with low solubility in soils. To further understand the fate of P applied to soils, two separate but related studies using three high P-fixing soil types each were used for which the objectives were to investigate the mobility, availability, and reaction products from two granular and one liquid P fertilizer alone or plus a fertilizer enhancement product. Energy dispersive spectroscopy showed a substantial amount of P remained in the granule following a 5-week incubation. At the end of the 35-day incubation period there was evidence that the fluid fertilizer was superior over the granular sources in terms of enhanced diffusion and extractability of P for three calcareous soils with varying levels of CaCO$_{3}$. Phosphorus x-ray absorption near-edge structure (XANES) spectroscopy results in conjunction with resin-extractable P indicated a strong negative correlation between Ca-P solids formed and P extractability, suggesting that degree of Ca-P formation limits P solubility. For the three acidic P-fixing soils the results were complex. In two out of three acid soils, liquid P treatments diffused farther from the application point than the granular treatments. Phosphorus XANES results suggested that Fe-P or Al-P interactions control the overall P solubility. Integration of pH, resin extractable-P and XANES results suggested the P retention mechanism was either dominated by adsorption or precipitation depending on soil pH. More acidic soil conditions favored precipitation.

The objectives of the third study were to observe how long-term (14 years) addition of P with or without N influences the inorganic and organic P pools in a native grassland soil using sequential fractionation, XANES, and \³\¹P-nuclear magnetic resonance (NMR) spectroscopy. The overall results suggested that P and N fertilization and associated changes in plant productivity induced significant changes in soil P pools such as Ca-P, phytic acid, monoesters, and residual forms of P. The addition of P alone induced formation of inorganic P forms while the addition of P and N induced transformation of residual P forms into more labile and/or organic P forms.

}, keywords = {LTER-KNZ, High phosphorus-fixing acid soil, High phosphorus-fixing calcareous soil, High phosphorus-fixing soil, Soil phosphorus, Soil phosphorus cycle, Tall grassland soils}, url = {http://krex.k-state.edu/dspace/handle/2097/34586}, author = {Pierzynski, Joy} } @article {KNZ001730, title = {Few multiyear precipitation{\textendash}reduction experiments find a shift in the productivity{\textendash}precipitation relationship}, journal = {Global Change Biology}, volume = {22}, year = {2016}, pages = {2570-2581}, abstract = {

Well-defined productivity\–precipitation relationships of ecosystems are needed as benchmarks for the validation of land models used for future projections. The productivity\–precipitation relationship may be studied in two ways: the spatial approach relates differences in productivity to those in precipitation among sites along a precipitation gradient (the spatial fit, with a steeper slope); the temporal approach relates interannual productivity changes to variation in precipitation within sites (the temporal fits, with flatter slopes). Precipitation\–reduction experiments in natural ecosystems represent a complement to the fits, because they can reduce precipitation below the natural range and are thus well suited to study potential effects of climate drying. Here, we analyse the effects of dry treatments in eleven multiyear precipitation\–manipulation experiments, focusing on changes in the temporal fit. We expected that structural changes in the dry treatments would occur in some experiments, thereby reducing the intercept of the temporal fit and displacing the productivity\–precipitation relationship downward the spatial fit. The majority of experiments (72\%) showed that dry treatments did not alter the temporal fit. This implies that current temporal fits are to be preferred over the spatial fit to benchmark land-model projections of productivity under future climate within the precipitation ranges covered by the experiments. Moreover, in two experiments, the intercept of the temporal fit unexpectedly increased due to mechanisms that reduced either water loss or nutrient loss. The expected decrease of the intercept was observed in only one experiment, and only when distinguishing between the late and the early phases of the experiment. This implies that we currently do not know at which precipitation\–reduction level or at which experimental duration structural changes will start to alter ecosystem productivity. Our study highlights the need for experiments with multiple, including more extreme, dry treatments, to identify the precipitation boundaries within which the current temporal fits remain valid.

}, keywords = {LTER-KNZ}, doi = {10.1111/gcb.13269}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.13269}, author = {Estiarte, M. and Vicca, S. and Pe{\~n}uelas, J. and Michael Bahn and Beier, C. and Emmett, B.A. and Fay, P.A. and Hanson, P.J. and R. Hasibeder and Kigel, J. and Kr{\"o}el-Dulay, G. and Larsen, K.S. and Lellei-Kov{\'a}cs, E. and Limousin, J-M. and Ogaya, R. and Ourcival, J-M. and Reinsch, S. and Sala, O.E. and Schmidt, I.K. and Sternberg, M. and Tielb{\"o}rger, K. and Tietema, A. and Janssens, I.A.} } @article {KNZ001787, title = {Integrative modelling reveals mechanisms linking productivity and plant species richness}, journal = {Nature}, volume = {529}, year = {2016}, pages = {390 - 393}, abstract = {

How ecosystem productivity and species richness are interrelated is one of the most debated subjects in the history of ecology1. Decades of intensive study have yet to discern the actual mechanisms behind observed global patterns2, 3. Here, by integrating the predictions from multiple theories into a single model and using data from 1,126 grassland plots spanning five continents, we detect the clear signals of numerous underlying mechanisms linking productivity and richness. We find that an integrative model has substantially higher explanatory power than traditional bivariate analyses. In addition, the specific results unveil several surprising findings that conflict with classical models4, 5, 6, 7. These include the isolation of a strong and consistent enhancement of productivity by richness, an effect in striking contrast with superficial data patterns. Also revealed is a consistent importance of competition across the full range of productivity values, in direct conflict with some (but not all) proposed models. The promotion of local richness by macroecological gradients in climatic favourability, generally seen as a competing hypothesis8, is also found to be important in our analysis. The results demonstrate that an integrative modelling approach leads to a major advance in our ability to discern the underlying processes operating in ecological systems.

}, keywords = {LTER-KNZ}, doi = {10.1038/nature16524}, url = {https://www.nature.com/articles/nature16524}, author = {Grace, J.B. and Anderson, T.M. and Seabloom, E.W. and E.T. Borer and P. Adler and Harpole, W.S. and Hautier, Y. and Hillebrand, H. and Lind, E.M. and P{\"a}rtel, M. and J.D. Bakker and Buckley, Y.M. and Crawley, M.J. and Damschen, E.I. and Davies, K.F. and Fay, P.A. and Firn, J. and Gruner, D.S. and Hector, A. and Knops, J.M.H. and MacDougall, A.S. and Melbourne, B.A. and J.W. Morgan and Orrock, J.L. and Prober, S.M. and M.D. Smith} } @article {KNZ001798, title = {Quantifying global soil carbon losses in response to warming}, journal = {Nature}, volume = {540}, year = {2016}, pages = {104 - 108}, abstract = {

The majority of the Earth\’s terrestrial carbon is stored in the soil. If anthropogenic warming stimulates the loss of this carbon to the atmosphere, it could drive further planetary warming, Despite evidence that warming enhances carbon fluxes to and from the soil, the net global balance between these responses remains uncertain. Here we present a comprehensive analysis of warming-induced changes in soil carbon stocks by assembling data from 49 field experiments located across North America, Europe and Asia. We find that the effects of warming are contingent on the size of the initial soil carbon stock, with considerable losses occurring in high-latitude areas. By extrapolating this empirical relationship to the global scale, we provide estimates of soil carbon sensitivity to warming that may help to constrain Earth system model projections. Our empirical relationship suggests that global soil carbon stocks in the upper soil horizons will fall by 30\ \±\ 30 petagrams of carbon to 203\ \±\ 161 petagrams of carbon under one degree of warming, depending on the rate at which the effects of warming are realized. Under the conservative assumption that the response of soil carbon to warming occurs within a year, a business-as-usual climate scenario would drive the loss of 55\ \±\ 50 petagrams of carbon from the upper soil horizons by 2050. This value is around 12\–17 per cent of the expected anthropogenic emissions over this period. Despite the considerable uncertainty in our estimates, the direction of the global soil carbon response is consistent across all scenarios. This provides strong empirical support for the idea that rising temperatures will stimulate the net loss of soil carbon to the atmosphere, driving a positive land carbon\–climate feedback that could accelerate climate change.

}, keywords = {LTER-KNZ, Biogeochemistry, carbon cycle}, doi = {10.1038/nature20150}, url = {https://www.nature.com/articles/nature20150}, author = {Crowther, T. W. and Todd-Brown, K. E. O. and Rowe, C. W. and Wieder, W. R. and Carey, J. C. and Machmuller, M. B. and Snoek, B. L. and Fang, S. and Zhou, G. and Allison, S. D. and John M. Blair and Bridgham, S. D. and Burton, A. J. and Carrillo, Y. and Reich, P. B. and Clark, J. S. and Classen, A. T. and Dijkstra, F. A. and Elberling, B. and Emmett, B. A. and Estiarte, M. and Frey, S. D. and Guo, J. and Harte, J. and Jiang, L. and Johnson, B. R. and Kr{\"o}el-Dulay, G. and Larsen, K. S. and Laudon, H. and Lavallee, J. M. and Luo, Y. and Lupascu, M. and Ma, L. N. and Marhan, S. and Michelsen, A. and Mohan, J. and Niu, S. and Pendall, E. and {\~n}uelas, J. and Pfeifer-Meister, L. and Poll, C. and Reinsch, S. and Reynolds, L. L. and Schmidt, I. K. and Sistla, S. and Sokol, N. W. and Templer, P. H. and Treseder, K. K. and Welker, J. M. and Bradford, M. A.} } @article {KNZ001754, title = {Relatedness constrains virulence in an obligate avian brood parasite}, journal = {Ornithological Science}, volume = {15}, year = {2016}, pages = {191 - 201}, abstract = {

Virulence, the amount of harm a parasite inflicts on its host, is integral to elucidating the evolution of obligate avian brood parasitism. However, we lack information regarding how relatedness is linked to changes in behavior and the degree of harm that brood parasites cause to their hosts (i.e., virulence). The kin competition hypothesis combines theory from offspring signaling and parasite virulence models and states that the begging intensity of co-infecting parasites is driven by their relatedness, with concomitant changes in the degree of virulence expressed by parasitic young. We tested this hypothesis using the Brown-headed Cowbird Molothrus ater, an obligate brood parasitic bird whose virulence at the nestling stage is mediated by vigorous begging displays that are used to outcompete host young during feeding bouts. We found support for both predictions of the kin competition hypothesis: first, the begging intensity of cowbirds was greater in a population where cowbirds typically competed against unrelated host nestmates, relative to a population where they often competed against kin. Second, the greater intensity of begging in cowbirds was positively associated with decreased growth in host offspring during the developmental period. Given the dearth of studies on virulence in avian brood parasites, our results notably extend our understanding of how relatedness is linked to parasite behavior and virulence, and they highlight how spatially-isolated host populations can harbor different levels of virulence that are driven by competitive interactions between co-infecting parasites.

}, keywords = {LTER-KNZ, begging, brown-headed cowbird, Kin competition hypothesis, Molothrus ater, Virulence}, doi = {10.2326/osj.15.191}, url = {https://doi.org/10.2326/osj.15.191}, author = {Rivers, J.W. and Peer, B.D.} } @article {KNZ001823, title = {A safety vs efficiency trade-off identified in the hydraulic pathway of grass leaves is decoupled from photosynthesis, stomatal conductance and precipitation}, journal = {New Phytologist}, volume = {210}, year = {2016}, pages = {97-107}, abstract = {

A common theme in plant physiological research is the trade-off between stress tolerance and growth; an example of this trade-off at the tissue level is the safety vs efficiency hypothesis, which suggests that plants with the greatest resistance to hydraulic failure should have low maximum hydraulic conductance. Here, we quantified the leaf-level drought tolerance of nine C4 grasses as the leaf water potential at which plants lost 50\% (P50 \× RR ) of maximum leaf hydraulic conductance (Ksat ), and compared this trait with other leaf-level and whole-plant functions. We found a clear trade-off between Ksat and P50 \× RR when Ksat was normalized by leaf area and mass (P = 0.05 and 0.01, respectively). However, no trade-off existed between P50 \× RR and gas-exchange rates; rather, there was a positive relationship between P50 \× RR and photosynthesis (P = 0.08). P50 \× RR was not correlated with species distributions based on precipitation (P = 0.70), but was correlated with temperature during the wettest quarter of the year (P \< 0.01). These results suggest a trade-off between safety and efficiency in the hydraulic system of grass leaves, which can be decoupled from other leaf-level functions. The unique physiology of C4 plants and adaptations to pulse-driven systems may provide mechanisms that could decouple hydraulic conductance from other plant functions.

}, keywords = {LTER-KNZ}, doi = {http://dx.doi.org/10.1111/nph.13781}, url = {https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.13781}, author = {Ocheltree, Troy W. and Jesse B. Nippert and Prasad, P. V. Vara} } @article {KNZ001709, title = {The sensitivity of carbon exchanges in Great Plains grasslands to precipitation variability}, journal = {Journal of Geophysical Research: Biogeosciences}, volume = {121}, year = {2016}, pages = {280-294}, abstract = {

In the Great Plains, grassland carbon dynamics differ across broad gradients of precipitation and temperature, yet finer-scale variation in these variables may also affect grassland processes. Despite the importance of grasslands, there is little information on how fine-scale relationships compare between them regionally. We compared grassland C exchanges, energy partitioning and precipitation variability in eight sites in the eastern and western Great Plains using eddy covariance and meteorological data. During our study, both eastern and western grasslands varied between an average net carbon sink and a net source. Eastern grasslands had a moderate vapor pressure deficit (VPD = 0.95 kPa) and high growing season gross primary productivity (GPP = 1010 \± 218 g C m\−2 m\−2 y\−1). Western grasslands had a growing season with higher VPD (1.43 kPa) and lower GPP (360 \± 127 g C m\−2 m\−2 y\−1). Western grasslands were sensitive to precipitation at daily timescales, whereas eastern grasslands were sensitive at monthly and seasonal timescales. Our results support the expectation that C exchanges in these grasslands differ as a result of varying precipitation regimes. Because eastern grasslands are less influenced by short-term variability in rainfall than western grasslands, the effects of precipitation change are likely to be more predictable in eastern grasslands because the timescales of variability that must be resolved are relatively longer. We postulate increasing regional heterogeneity in grassland C exchanges in the Great Plains in coming decades.

}, keywords = {LTER-KNZ}, doi = {10.1002/2015JG003205}, url = {https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015JG003205}, author = {Petrie, M.D. and N. Brunsell and Vargas, R. and Scott. L. Collins and Flanagan, L.B. and Hanan, N.P. and Litvak, M.E. and Suyker, A.E.} } @article {KNZ001756, title = {Tight coupling of leaf area index to canopy nitrogen and phosphorus across heterogeneous tallgrass prairie communities}, journal = {Oecologia}, volume = {182}, year = {2016}, pages = {889 - 898}, abstract = {

Nitrogen (N) and phosphorus (P) are limiting nutrients for many plant communities worldwide. Foliar N and P along with leaf area are among the most important controls on photosynthesis and hence productivity. However, foliar N and P are typically assessed as species level traits, whereas productivity is often measured at the community scale. Here, we compared the community-level traits of leaf area index (LAI) to total foliar nitrogen (TFN) and total foliar phosphorus (TFP) across nearly three orders of magnitude LAI in grazed and ungrazed tallgrass prairie in north-eastern Kansas, USA. LAI was strongly correlated with both TFN and TFP across communities, and also within plant functional types (grass, forb, woody, and sedge) and grazing treatments (bison or cattle, and ungrazed). Across almost the entire range of LAI values and contrasting communities, TFN:TFP ratios indicated co-limitation by N and P in almost all communities; this may further indicate a community scale trend of an optimal N and P allocation per unit leaf area for growth. Previously, results from the arctic showed similar tight relationships between LAI:TFN, suggesting N is supplied to canopies to maximize photosynthesis per unit leaf area. This tight coupling between LAI, N, and P in tallgrass prairie suggests a process of optimal allocation of N and P, wherein LAI remains similarly constrained by N and P despite differences in species composition, grazing, and canopy density.

}, keywords = {LTER-KNZ, Co-limitation, fire, grassland, grazers, nutrients}, issn = {0029-8549}, doi = {10.1007/s00442-016-3713-3}, url = {https://link.springer.com/article/10.1007\%2Fs00442-016-3713-3}, author = {Klodd, A.E. and Jesse B. Nippert and Z. Ratajczak and Waring, H. and Phoenix, G.K.} } @article {KNZ001729, title = {Warm spring reduced carbon cycle impact of the 2012 US summer drought}, journal = {Proceedings of the National Academy of Sciences}, year = {2016}, pages = {201519620}, abstract = {

The global terrestrial carbon sink offsets one-third of the world\’s fossil fuel emissions, but the strength of this sink is highly sensitive to large-scale extreme events. In 2012, the contiguous United States experienced exceptionally warm temperatures and the most severe drought since the Dust Bowl era of the 1930s, resulting in substantial economic damage. It is crucial to understand the dynamics of such events because warmer temperatures and a higher prevalence of drought are projected in a changing climate. Here, we combine an extensive network of direct ecosystem flux measurements with satellite remote sensing and atmospheric inverse modeling to quantify the impact of the warmer spring and summer drought on biosphere-atmosphere carbon and water exchange in 2012. We consistently find that earlier vegetation activity increased spring carbon uptake and compensated for the reduced uptake during the summer drought, which mitigated the impact on net annual carbon uptake. The early phenological development in the Eastern Temperate Forests played a major role for the continental-scale carbon balance in 2012. The warm spring also depleted soil water resources earlier, and thus exacerbated water limitations during summer. Our results show that the detrimental effects of severe summer drought on ecosystem carbon storage can be mitigated by warming-induced increases in spring carbon uptake. However, the results also suggest that the positive carbon cycle effect of warm spring enhances water limitations and can increase summer heating through biosphere\–atmosphere feedbacks.

}, keywords = {LTER-KNZ, biosphere{\textendash}atmosphere feedbacks, carbon uptake, ecosystem fluxes, Eddy covariance, seasonal climate anomalies}, issn = {0027-8424}, doi = {10.1073/pnas.1519620113}, url = {https://www.pnas.org/content/113/21/5880}, author = {Wolf, S. and Keenan, T.F. and Fisher, J.B. and Baldocchi, D.D. and Desai, A.R. and Richardson, A.D. and Scott, R.L. and Law, B.E. and Litvak, M.E. and N. Brunsell and Peters, W. and van der Laan-Luijkx, I.T.} } @article {KNZ001698, title = {Anthropogenic nitrogen deposition predicts local grassland primary production worldwide}, journal = {Ecology}, volume = {96}, year = {2015}, pages = {1459 -1465}, abstract = {

Humans dominate many important Earth system processes including the nitrogen (N) cycle. Atmospheric N deposition affects fundamental processes such as carbon cycling, climate regulation, and biodiversity, and could result in changes to fundamental Earth system processes such as primary production. Both modelling and experimentation have suggested a role for anthropogenically altered N deposition in increasing productivity, nevertheless, current understanding of the relative strength of N deposition with respect to other controls on production such as edaphic conditions and climate is limited. Here we use an international multiscale data set to show that atmospheric N deposition is positively correlated to aboveground net primary production (ANPP) observed at the 1-m2 level across a wide range of herbaceous ecosystems. N deposition was a better predictor than climatic drivers and local soil conditions, explaining 16\% of observed variation in ANPP globally with an increase of 1 kg N\·ha\−1\·yr\−1 increasing ANPP by 3\%. Soil pH explained 8\% of observed variation in ANPP while climatic drivers showed no significant relationship. Our results illustrate that the incorporation of global N deposition patterns in Earth system models are likely to substantially improve estimates of primary production in herbaceous systems. In herbaceous systems across the world, humans appear to be partially driving local ANPP through impacts on the N cycle.

}, keywords = {LTER-KNZ}, doi = {http://dx.doi.org/10.1890/14-1902.1}, url = {https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/14-1902.1}, author = {Stevens, C.J. and Lind, E.M. and Hautier, Y. and Harpole, W.S. and E.T. Borer and Hobbie, S. and Seabloom, E.Q. and L. Ladwig and J.D. Bakker and Chu, C. and Scott. L. Collins and Davies, K.F. and Firn, J. and Hillebrand, H. and Kimberly J. La Pierre and MacDougall, A.S. and Melbourne, B.A. and McCulley, R.L. and J.W. Morgan and Orrock, J.L. and Prober, S.M. and A. Risch and Schultz, M. and Wragg, P.D.} } @article {KNZ001789, title = {Consistent responses of soil microbial communities to elevated nutrient inputs in grasslands across the globe}, journal = {Proceedings of the National Academy of Sciences}, volume = {112}, year = {2015}, pages = {10967 - 10972}, abstract = {

Soil microorganisms are critical to ecosystem functioning and the maintenance of soil fertility. However, despite global increases in the inputs of nitrogen (N) and phosphorus (P) to ecosystems due to human activities, we lack a predictive understanding of how microbial communities respond to elevated nutrient inputs across environmental gradients. Here we used high-throughput sequencing of marker genes to elucidate the responses of soil fungal, archaeal, and bacterial communities using an N and P addition experiment replicated at 25 globally distributed grassland sites. We also sequenced metagenomes from a subset of the sites to determine how the functional attributes of bacterial communities change in response to elevated nutrients. Despite strong compositional differences across sites, microbial communities shifted in a consistent manner with N or P additions, and the magnitude of these shifts was related to the magnitude of plant community responses to nutrient inputs. Mycorrhizal fungi and methanogenic archaea decreased in relative abundance with nutrient additions, as did the relative abundances of oligotrophic bacterial taxa. The metagenomic data provided additional evidence for this shift in bacterial life history strategies because nutrient additions decreased the average genome sizes of the bacterial community members and elicited changes in the relative abundances of representative functional genes. Our results suggest that elevated N and P inputs lead to predictable shifts in the taxonomic and functional traits of soil microbial communities, including increases in the relative abundances of faster-growing, copiotrophic bacterial taxa, with these shifts likely to impact belowground ecosystems worldwide.

}, keywords = {LTER-KNZ, Fertilization, shotgun metagenomics, Soil bacteria, Soil ecology, Soil fungi}, doi = {10.1073/pnas.1508382112}, url = {https://www.pnas.org/content/112/35/10967}, author = {Leff, J.W. and Jones, S.E. and Prober, S.M. and Barber{\'a}n, A. and E.T. Borer and Firn, J.L. and Harpole, W.S. and Hobbie, S.E. and Hofmockel, K.S. and Knops, J.M.H. and McCulley, R.L. and Kimberly J. La Pierre and A. Risch and Seabloom, E.W. and Sch{\"u}tz, Martin and Steenbock, C. and Stevens, C.J. and Fierer, N.} } @article {KNZ001683, title = {Contrasting above- and belowground sensitivity of three Great Plains grasslands to altered rainfall regimes}, journal = {Global Change Biology}, volume = {21}, year = {2015}, pages = {335 -344}, abstract = {

Intensification of the global hydrological cycle with atmospheric warming is expected to increase interannual variation in precipitation amount and the frequency of extreme precipitation events. Although studies in grasslands have shown sensitivity of aboveground net primary productivity (ANPP) to both precipitation amount and event size, we lack equivalent knowledge for responses of belowground net primary productivity (BNPP) and NPP. We conducted a 2-year experiment in three US Great Plains grasslands \– the C4-dominated shortgrass prairie (SGP; low ANPP) and tallgrass prairie (TGP; high ANPP), and the C3-dominated northern mixed grass prairie (NMP; intermediate ANPP) \– to test three predictions: (i) both ANPP and BNPP responses to increased precipitation amount would vary inversely with mean annual precipitation (MAP) and site productivity; (ii) increased numbers of extreme rainfall events during high-rainfall years would affect high and low MAP sites differently; and (iii) responses belowground would mirror those aboveground. We increased growing season precipitation by as much as 50\% by augmenting natural rainfall via (i) many (11\–13) small or (ii) fewer (3\–5) large watering events, with the latter coinciding with naturally occurring large storms. Both ANPP and BNPP increased with water addition in the two C4 grasslands, with greater ANPP sensitivity in TGP, but greater BNPP and NPP sensitivity in SGP. ANPP and BNPP did not respond to any rainfall manipulations in the C3-dominated NMP. Consistent with previous studies, fewer larger (extreme) rainfall events increased ANPP relative to many small events in SGP, but event size had no effect in TGP. Neither system responded consistently above- and belowground to event size; consequently, total NPP was insensitive to event size. The diversity of responses observed in these three grassland types underscores the challenge of predicting responses relevant to C cycling to forecast changes in precipitation regimes even within relatively homogeneous biomes such as grasslands.

}, keywords = {LTER-KNZ}, doi = {10.1111/gcb.12673}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.12673}, author = {K.R. Wilcox and Von Fischer, J.C. and Muscha, J.M. and Petersen, M.K. and Alan K. Knapp} } @article {KNZ001773, title = {Factors affecting female space use in ten populations of prairie chickens}, journal = {Ecosphere}, volume = {6}, year = {2015}, pages = {art166}, abstract = {

Conservation of wildlife depends on an understanding of the interactions between animal movements and key landscape factors. Habitat requirements of wide-ranging species often vary spatially, but quantitative assessment of variation among replicated studies at multiple sites is rare. We investigated patterns of space use for 10 populations of two closely related species of prairie grouse: Greater Prairie-Chickens (Tympanuchus cupido) and Lesser Prairie-Chickens (T. pallidicinctus). Prairie chickens require large, intact tracts of native grasslands, and are umbrella species for conservation of prairie ecosystems in North America. We used resource utilization functions to investigate space use by female prairie chickens during the 6-month breeding season from March through August in relation to lek sites, habitat conditions, and anthropogenic development. Our analysis included data from 382 radio-marked individuals across a major portion of the extant range. Our project is a unique opportunity to study comparative space use of prairie chickens, and we employed standardized methods that facilitated direct comparisons across an ecological gradient of study sites. Median home range size of females varied ~10-fold across 10 sites (3.6\–36.7 km2), and home ranges tended to be larger at sites with higher annual precipitation. Proximity to lek sites was a strong and consistent predictor of space use for female prairie chickens at all 10 sites. The relative importance of other predictors of space use varied among sites, indicating that generalized habitat management guidelines may not be appropriate for these two species. Prairie chickens actively selected for prairie habitats, even at sites where ~90\% of the land cover within the study area was prairie. A majority of the females monitored in our study (\>95\%) had activity centers within 5 km of leks, suggesting that conservation efforts can be effectively concentrated near active lek sites. Our data on female space use suggest that lek surveys of male prairie chickens can indirectly assess habitat suitability for females during the breeding season. Lek monitoring and surveys for new leks provide information on population trends, but can also guide management actions aimed at improving nesting and brood-rearing habitats.

}, keywords = {LTER-KNZ}, doi = {10.1890/ES14-00536.1}, url = {https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/ES14-00536.1}, author = {Winder, V.L. and Carrlson, K.M. and Gregory, A.J. and Hagen, C.A. and David A. Haukos and Kesler, D.C. and Larsson, L.C. and Matthews, T.W. and McNew, L.B. and Patten, M.A. and Pitman, J.C. and Powell, L.A. and Smith, J.A. and Thompson, T. and Wolfe, D.H. and Sandercock, B.K.} } @article {KNZ001705, title = {Formation of soil organic matter via biochemical and physical pathways of litter mass loss}, journal = {Nature Geoscience}, volume = {8}, year = {2015}, month = {Jul-09-2015}, pages = {776 - 779}, abstract = {Soil organic matter is the largest terrestrial carbon pool1. The pool size depends on the balance between formation of soil organic matter from decomposition of plant litter and its mineralization to inorganic carbon. Knowledge of soil organic matter formation remains limited2 and current C numerical models assume that stable soil organic matter is formed primarily from recalcitrant plant litter3. However, labile components of plant litter could also form mineral-stabilized soil organic matter4. Here we followed the decomposition of isotopically labelled above-ground litter and its incorporation into soil organic matter over three years in a grassland in Kansas, USA, and used laboratory incubations to determine the decay rates and pool structure of litter-derived organic matter. Early in decomposition, soil organic matter formed when non-structural compounds were lost from litter. Soil organic matter also formed at the end of decomposition, when both non-structural and structural compounds were lost at similar rates. We conclude that two pathways yield soil organic matter efficiently. A dissolved organic matter{\textendash}microbial path occurs early in decomposition when litter loses mostly non-structural compounds, which are incorporated into microbial biomass at high rates, resulting in efficient soil organic matter formation. An equally efficient physical-transfer path occurs when litter fragments move into soil.}, keywords = {LTER-KNZ, Biogeochemistry, Environmental chemistry, Stable isotope analysis}, issn = {1752-0894}, doi = {10.1038/ngeo2520}, url = {http://www.nature.com/doifinder/10.1038/ngeo2520}, author = {Cotrufo, M.F. and Soong, Jennifer L. and Horton, Andrew J. and Campbell, Eleanor E. and Haddix, ~L. and Wall, Diana H. and Parton, William J.} } @article {KNZ001788, title = {Grassland productivity limited by multiple nutrients}, journal = {Nature Plants}, volume = {1}, year = {2015}, pages = {15080}, abstract = {

Terrestrial ecosystem productivity is widely accepted to be nutrient limited1. Although nitrogen (N) is deemed a key determinant of aboveground net primary production (ANPP)2,3, the prevalence of co-limitation by N and phosphorus (P) is increasingly recognized4,​5,​6,​7,​8. However, the extent to which terrestrial productivity is co-limited by nutrients other than N and P has remained unclear. Here, we report results from a standardized factorial nutrient addition experiment, in which we added N, P and potassium (K) combined with a selection of micronutrients (K+μ), alone or in concert, to 42 grassland sites spanning five continents, and monitored ANPP. Nutrient availability limited productivity at 31 of the 42 grassland sites. And pairwise combinations of N, P, and K+μ co-limited ANPP at 29 of the sites. Nitrogen limitation peaked in cool, high latitude sites. Our findings highlight the importance of less studied nutrients, such as K and micronutrients, for grassland productivity, and point to significant variations in the type and degree of nutrient limitation. We suggest that multiple-nutrient constraints must be considered when assessing the ecosystem-scale consequences of nutrient enrichment.

}, keywords = {LTER-KNZ}, doi = {10.1038/nplants.2015.80}, url = {https://www.nature.com/articles/nplants201580}, author = {Fay, P.A. and Prober, S.M. and Harpole, W.S. and Knops, J.M.H. and J.D. Bakker and E.T. Borer and Lind, E.M. and MacDougall, A.S. and Seabloom, E.W. and Wragg, P.D. and P. Adler and D.M. Blumenthal and Buckley, Y.M. and Chu, C. and Cleland, E.E. and Scott. L. Collins and Davies, K.F. and G. Du and Feng, X. and Firn, J. and Gruner, D.S. and Hagenah, N. and Hautier, Y. and Heckman, R.W. and Jin, V.L. and Kirkman, K.P. and Klein, J. and L. Ladwig and Li, Q. and McCulley, R.L. and Melbourne, B.A. and Mitchell, C.E. and Joslin L. Moore and J.W. Morgan and A. Risch and sch{\"u}tz, M. and Stevens, C.J. and Wedin, D.A. and Yang, L.H.} } @article {KNZ001776, title = {Long-term changes in structure and function of a tropical headwater stream following a disease-driven amphibian decline}, journal = {Freshwater Biology}, volume = {60}, year = {2015}, pages = {575 - 589}, abstract = {

1. Taxonomic and functional diversity in freshwater habitats is rapidly declining, but we know little about how such declines will ultimately affect ecosystems. Neotropical streams are currently experiencing massive losses of amphibians, with many losses linked to the chytrid fungus, Batrachochytrium dendrobatidis (Bd). 2. We examined the ecological consequences of the disease-driven loss of amphibians from a Panamanian stream. We quantified basal resources, macroinvertebrates, N uptake and fluxes through food-web components and ecosystem metabolism in 2012 and 2014 and compared them to pre-decline (2006) and 2 year post-decline (2008) values from a prior study. 3. Epilithon biomass accrued after the decline, more than doubling between 2006 and 2012, but then decreased fivefold from 2012 to 2014. In contrast, suspended particulate organic matter (SPOM) concentrations declined continuously after the amphibian decline through 2014. 4. Biomass of filter-feeding, grazing and shredding macroinvertebrates decreased from 2006 to 2014, while collector\–gatherers increased during the same time period. Macroinvertebrate taxa richness decreased from 2006 (52 taxa) to 2012 (30 taxa), with a subsequent increase to 51 taxa in 2014. 5. Community respiration, which initially decreased after the amphibian decline, remained lower than pre-decline in 2012 but was greater than pre-decline values in 2014. Gross primary production remained low and similar among years, while inline image uptake length in both 2012 and 2014 was longer than pre-decline. Nitrogen flux to epilithon increased after the decline and continued to do so through 2014, but N fluxes to fine particulate organic matter and SPOM decreased and remained low. 6. Our findings underscore the importance of studying the ecological consequences of declining biodiversity in natural systems over relatively long time periods. There was no evidence of functional redundancy or compensation by other taxa after the loss of amphibians, even after 8 years.

}, keywords = {LTER-KNZ}, doi = {10.1111/fwb.12505}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/fwb.12505}, author = {Rantala, H.M. and Nelson, A.M. and Fulgoni, J.N. and M.R. Whiles and Hall, R.O. and W. K. Dodds and Verburg, P. and Huryn, A. and Pringle, C.. and Kilham, S.S. and Lips, K.R. and Colon-Gaud, C. and Rugenski, A.T. and Peterson, S.D. and Fritz, K. and McLeran, K.E. and Connelly, S.} } @article {KNZ001678, title = {Plant diversity predicts beta but not alpha diversity of soil microbes across grasslands worldwide}, journal = {Ecology Letters}, volume = {18}, year = {2015}, pages = {85 -95}, abstract = {

Aboveground\–belowground interactions exert critical controls on the composition and function of terrestrial ecosystems, yet the fundamental relationships between plant diversity and soil microbial diversity remain elusive. Theory predicts predominantly positive associations but tests within single sites have shown variable relationships, and associations between plant and microbial diversity across broad spatial scales remain largely unexplored. We compared the diversity of plant, bacterial, archaeal and fungal communities in one hundred and forty-five 1 m2 plots across 25 temperate grassland sites from four continents. Across sites, the plant alpha diversity patterns were poorly related to those observed for any soil microbial group. However, plant beta diversity (compositional dissimilarity between sites) was significantly correlated with the beta diversity of bacterial and fungal communities, even after controlling for environmental factors. Thus, across a global range of temperate grasslands, plant diversity can predict patterns in the composition of soil microbial communities, but not patterns in alpha diversity.

}, keywords = {LTER-KNZ}, doi = {10.1111/ele.12381}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/ele.12381}, author = {Prober, S.M. and Leff, J.W. and Bates, S.T. and E.T. Borer and Firn, J. and Harpole, W.S. and Lind, E.M. and Seabloom, E.W. and P. Adler and J.D. Bakker and E.E Cleland and DeCrappeo, N.M. and DeLorenze, E. and Hagenah, N. and Hautier, Y. and Hofmockel, K.S. and Kirkman, K.P. and Knops, J.M.H. and Kimberly J. La Pierre and MacDougall, A.S. and McCulley, R.L. and Mitchell, C.E. and A. Risch and Schuetz, M. and Stevens, C.J. and Williams, R.J. and Fierer, N.} } @article {KNZ001697, title = {Plant species{\textquoteright} origin predicts dominance and response to nutrient enrichment and herbivores in global grasslands}, journal = {Nature Communications}, volume = {6}, year = {2015}, pages = {7710 -}, abstract = {

Exotic species dominate many communities; however the functional significance of species\’ biogeographic origin remains highly contentious. This debate is fuelled in part by the lack of globally replicated, systematic data assessing the relationship between species provenance, function and response to perturbations. We examined the abundance of native and exotic plant species at 64 grasslands in 13 countries, and at a subset of the sites we experimentally tested native and exotic species responses to two fundamental drivers of invasion, mineral nutrient supplies and vertebrate herbivory. Exotic species are six times more likely to dominate communities than native species. Furthermore, while experimental nutrient addition increases the cover and richness of exotic species, nutrients decrease native diversity and cover. Native and exotic species also differ in their response to vertebrate consumer exclusion. These results suggest that species origin has functional significance, and that eutrophication will lead to increased exotic dominance in grasslands.

}, keywords = {LTER-KNZ, Biological sciences, ecology, Plant sciences}, doi = {10.1038/ncomms8710}, url = {https://www.nature.com/articles/ncomms8710}, author = {Seabloom, E.W. and E.T. Borer and Buckley, Y. and Cleland, E.E. and Davies, K.F. and Firn, J. and Harpole, W.S. and Hautier, Y. and Lind, E. and MacDougall, A.S. and Orrock, J.L. and Prober, S.M. and P. Adler and Anderson, T.M. and J.D. Bakker and L.A. Biederman and D.M. Blumenthal and C.S. Brown and Brudvig, L.A. and Cadotte, M. and Chu, C. and Cottingham, K.L. and Crawley, M.J. and Damschen, E.I. and D{\textquoteright}Antonio, C.M. and CeCrappeo, N.M. and G. Du and Fay, P.A. and Frater, P. and Gruner, D.S. and Hagenah, N. and Hector, A. and Hillebrand, H. and Hofmockel, K.S. and Humphries, H.C. and Jin, V.L. and Kay, A.D. and Kirkman, K.P. and Klein, J.A. and Knops, J.M.H. and Kimberly J. La Pierre and L. Ladwig and Lambrinos, J.G. and Li, Q. and Li, W. and Marushia, R.} } @article {KNZ001777, title = {Quantifying ambient nitrogen uptake and functional relationships of uptake versus concentration in streams: a comparison of stable isotope, pulse, and plateau approaches}, journal = {Biogeochemistry}, volume = {125}, year = {2015}, pages = {65 - 79}, abstract = {

Nutrient releases and spiraling metrics are frequently used to quantify the downstream transport of nutrients and to better understand the effects of anthropogenic inputs to downstream waters. Ambient uptake rates in streams can be measured through stable isotope enrichments, while pulse and plateau additions can estimate such rates via extrapolation and modeling techniques, respectively. Data from these releases can be used to estimate ambient uptake rates from nutrient additions and possibly determine the functional relationships between nutrient concentrations and uptake rates. Here, we compared estimated ambient rates calculated from established pulse and plateau approaches, results obtained from new modeling approaches, and rates at ambient concentrations from stable isotope enrichments. Comparative releases of NH4Cl and 15NH4Cl were conducted in four experimental reaches across the grassland Kings Creek and urban Campus Creek, KS. Nutrient uptake was predominantly linear with increasing ammonium. Estimated ambient uptake rates varied among sites, release methods, and data analysis approaches. However, plateau ambient rates from new modeling approaches matched closely with measured ambient rates from isotope enrichments at three sites, suggesting that modeled plateau data may be best for a first look at determining nutrient uptake rates at an individual site. Limitations and benefits of each approach vary; however, baseflow discharge may be a key driver when choosing a method. If possible, multiple methods should be attempted at each location and under each novel set of conditions to determine the best approach prior to designing and implementing a more extensive series of measurements.

}, keywords = {LTER-KNZ, Ammonium uptake, nutrient spiraling, TASCC, uptake length}, doi = {10.1007/s10533-015-0112-5}, url = {https://link.springer.com/article/10.1007\%2Fs10533-015-0112-5}, author = {Trentman, M.T. and W. K. Dodds and Fencl, J.S. and Gerber, K. and Guarneri, J. and Hitchman, S.M. and Peterson, Z. and R{\"u}egg, J.} } @article {KNZ001792, title = {Anthropogenic-based regional-scale factors most consistently explain plot-level exotic diversity in grasslands}, journal = {Global Ecology and Biogeography}, volume = {23}, year = {2014}, pages = {802 - 810}, abstract = {

Aim Evidence linking the accumulation of exotic species to the suppression of native diversity is equivocal, often relying on data from studies that have used different methods. Plot-level studies often attribute inverse relationships between native and exotic diversity to competition, but regional abiotic filters, including anthropogenic influences, can produce similar patterns. We seek to test these alternatives using identical scale-dependent sampling protocols in multiple grasslands on two continents. Location Thirty-two grassland sites in North America and Australia. Methods We use multiscale observational data, collected identically in grain and extent at each site, to test the association of local and regional factors with the plot-level richness and abundance of native and exotic plants. Sites captured environmental and anthropogenic gradients including land-use intensity, human population density, light and soil resources, climate and elevation. Site selection occurred independently of exotic diversity, meaning that the numbers of exotic species varied randomly thereby reducing potential biases if only highly invaded sites were chosen. Results Regional factors associated directly or indirectly with human activity had the strongest associations with plot-level diversity. These regional drivers had divergent effects: urban-based economic activity was associated with high exotic\ :\ native diversity ratios; climate- and landscape-based indicators of lower human population density were associated with low exotic\ :\ native ratios. Negative correlations between plot-level native and exotic diversity, a potential signature of competitive interactions, were not prevalent; this result did not change along gradients of productivity or heterogeneity. Main conclusion We show that plot-level diversity of native and exotic plants are more consistently associated with regional-scale factors relating to urbanization and climate suitability than measures indicative of competition. These findings clarify the long-standing difficulty in resolving drivers of exotic diversity using single-factor mechanisms, suggesting that multiple interacting anthropogenic-based processes best explain the accumulation of exotic diversity in modern landscapes.

}, keywords = {LTER-KNZ}, doi = {10.1111/geb.12157}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/geb.12157}, author = {MacDougall, A.S. and Bennett, J.R. and Firn, J. and Seabloom, E.W. and E.T. Borer and Lind, E.M. and Orrock, J.L. and Harpole, W.S. and Hautier, Y. and P. Adler and Cleland, E. and Davies, K. and Melbourne, B. and Prober, S.M. and J.D. Bakker and Fay, P.A. and Jin, V.L. and Kendig, A. and Kimberly J. La Pierre and Joslin L. Moore and J.W. Morgan and Stevens, C.J.} } @article {KNZ001633, title = {Differential effects of extreme drought on production and respiration: Synthesis and modeling analysis}, journal = {Biogeosciences}, volume = {11}, year = {2014}, pages = {621 -633}, abstract = {

Extremes in climate may severely impact ecosystem structure and function, with both the magnitude and rate of response differing among ecosystem types and processes. We conducted a modeling analysis of the effects of extreme drought on two key ecosystem processes, production and respiration, and, to provide a broader context, we complemented this with a synthesis of published results that cover a wide variety of ecosystems. The synthesis indicated that across a broad range of biomes, gross primary production (GPP) was generally more sensitive to extreme drought (defined as proportional reduction relative to average rainfall periods) than was ecosystem respiration (ER). Furthermore, this differential sensitivity between production and respiration increased as drought severity increased; it occurred only in grassland ecosystems, and not in evergreen needle-leaf and broad-leaf forests or woody savannahs. The modeling analysis was designed to enable a better understanding of the mechanisms underlying this pattern, and focused on four grassland sites arrayed across the Great Plains, USA. Model results consistently showed that net primary productivity (NPP) was reduced more than heterotrophic respiration (Rh) by extreme drought (i.e., 67\% reduction in annual ambient rainfall) at all four study sites. The sensitivity of NPP to drought was directly attributable to rainfall amount, whereas the sensitivity of Rh to drought was driven by soil drying, reduced carbon (C) input and a drought-induced reduction in soil C content \– a much slower process. However, differences in reductions in NPP and Rh diminished as extreme drought continued, due to a gradual decline in the soil C pool leading to further reductions in Rh. We also varied the way in which drought was imposed in the modeling analysis; it was either imposed by simulating reductions in rainfall event size (ESR) or by reducing rainfall event number (REN). Modeled NPP and Rh decreased more by ESR than REN at the two relatively mesic sites but less so at the two xeric sites. Our findings suggest that responses of production and respiration differ in magnitude, occur on different timescales, and are affected by different mechanisms under extreme, prolonged drought.

}, keywords = {LTER-KNZ}, doi = {10.5194/bg-11-621-2014}, url = {https://www.biogeosciences.net/11/621/2014/}, author = {Shi, Z. and Thomey, M.L. and Mowll, M. and Litvak, M.E. and N. Brunsell and Scott. L. Collins and Pockman, W.T. and M.D. Smith and Alan K. Knapp and Luo, Y.} } @article {KNZ001632, title = {Eutrophication weakens stabilizing effects of diversity in natural grasslands}, journal = {Nature}, volume = {508}, year = {2014}, pages = {521 -525}, abstract = {

Studies of experimental grassland communities1, 2, 3, 4, 5, 6, 7 have demonstrated that plant diversity can stabilize productivity through species asynchrony, in which decreases in the biomass of some species are compensated for by increases in others1, 2. However, it remains unknown whether these findings are relevant to natural ecosystems, especially those for which species diversity is threatened by anthropogenic global change8, 9, 10, 11. Here we analyse diversity\–stability relationships from 41 grasslands on five continents and examine how these relationships are affected by chronic fertilization, one of the strongest drivers of species loss globally8. Unmanipulated communities with more species had greater species asynchrony, resulting in more stable biomass production, generalizing a result from biodiversity experiments to real-world grasslands. However, fertilization weakened the positive effect of diversity on stability. Contrary to expectations, this was not due to species loss after eutrophication but rather to an increase in the temporal variation of productivity in combination with a decrease in species asynchrony in diverse communities. Our results demonstrate separate and synergistic effects of diversity and eutrophication on stability, emphasizing the need to understand how drivers of global change interactively affect the reliable provisioning of ecosystem services in real-world systems.

}, keywords = {LTER-KNZ, Biodiversity, Community ecology, Grassland ecology}, doi = {10.1038/nature13014}, url = {https://www.nature.com/articles/nature13014}, author = {Hautier, Y. and Seabloom, E.W. and E.T. Borer and P. Adler and Harpole, W.S. and Hillebrand, H. and Lind, E.M. and MacDougall, A.S. and Stevens, C.J. and J.D. Bakker and Buckley, Y.M. and Chu, C. and Scott. L. Collins and Daleo, P. and Damschen, E.I. and Davies, K.F. and Fay, P.A. and Firn, J. and Gruner, D.S. and Jin, V.L. and Klein, J.A. and Knops, J.M.H. and Kimberly J. La Pierre and Li, W. and McCulley, R.L. and Melbourne, B.A. and Joslin L. Moore and O{\textquoteright}Halloran, L.R. and Prober, S.M. and A. Risch and Sankaran, M. and Schuetz, M. and Hector, A.} } @article {KNZ001637, title = {FOAM: Functional Ontology Assignments for Metagenomes: a Hidden Markov Model (HMM) database with environmental focus}, journal = {Nucleic Acids Research}, volume = {42: e145}, year = {2014}, abstract = {

A new functional gene database, FOAM (Functional Ontology Assignments for Metagenomes), was developed to screen environmental metagenomic sequence datasets. FOAM provides a new functional ontology dedicated to classify gene functions relevant to environmental microorganisms based on Hidden Markov Models (HMMs). Sets of aligned protein sequences (i.e. \‘profiles\’) were tailored to a large group of target KEGG Orthologs (KOs) from which HMMs were trained. The alignments were checked and curated to make them specific to the targeted KO. Within this process, sequence profiles were enriched with the most abundant sequences available to maximize the yield of accurate classifier models. An associated functional ontology was built to describe the functional groups and hierarchy. FOAM allows the user to select the target search space before HMM-based comparison steps and to easily organize the results into different functional categories and subcategories. FOAM is publicly available at http://portal.nersc.gov/project/m1317/FOAM/.

}, keywords = {LTER-KNZ}, doi = {10.1093/nar/gku702}, url = {https://academic.oup.com/nar/article/42/19/e145/2902479}, author = {Prestat, E. and David, M. and Hultman, J. and Tas, N. and Lamendella, R. and Dvornik, J. and Mackelprang, R. and Myrold, D.D. and A. Jumpponen and Tringe, S. and Holman, E. and Mavromatis, K. and Jansson, J.K.} } @article {KNZ001793, title = {Herbivores and nutrients control grassland plant diversity via light limitation}, journal = {Nature}, volume = {508}, year = {2014}, pages = {517 - 520}, keywords = {LTER-KNZ}, doi = {10.1038/nature13144}, url = {https://www.nature.com/articles/nature13144}, author = {E.T. Borer and Seabloom, E.W. and Gruner, D.S. and Harpole, W.S and Hillebrand, H. and Lind, E.M. and P. Adler and J. Alberti and Anderson, T.M. and J.D. Bakker and L.A. Biederman and D.M. Blumenthal and C.S. Brown and Brudvig, L.A. and Buckley, Y.M. and Cadotte, M. and Chu, C. and Cleland, E.E. and Crawley, M.J. and Daleo, P. and Damschen, E.I. and Davies, K.F. and DeCrappeo, N.M. and G. Du and Firn, J. and Hautier, Y. and Heckman, R.W. and Hector, A. and HilleRisLambers, J. and Iribarne, Oscar and Klein, J.A. and Knops, J.M.H. and Kimberly J. La Pierre and Leakey, A.D.B. and Li, W. and MacDougall, A.S. and McCulley, R.L. and Melbourne, B.A. and Mitchell, C.E. and Joslin L. Moore and Mortensen, B. and O{\textquoteright}Halloran, L.R. and Orrock, J.L. and Pascual, J. and Prober, S.M. and Pyke, D.A. and A. Risch and Schuetz, M. and M.D. Smith and Stevens, C.J. and L.L. Sullivan and Williams, R.J. and Wragg, P.D. and Wright, J.P. and Yang, L.H.} } @article {KNZ001614, title = {Soil animal responses to moisture availability are largely scale, not ecosystem dependent: Insight from a cross-site study}, journal = {Global Change Biology}, volume = {20}, year = {2014}, pages = {2631 -2643}, abstract = {

Climate change will result in reduced soil water availability in much of the world either due to changes in precipitation or increased temperature and evapotranspiration. How communities of mites and nematodes may respond to changes in moisture availability is not well known, yet these organisms play important roles in decomposition and nutrient cycling processes. We determined how communities of these organisms respond to changes in moisture availability and whether common patterns occur along fine-scale gradients of soil moisture within four individual ecosystem types (mesic, xeric and arid grasslands and a polar desert) located in the western United States and Antarctica, as well as across a cross-ecosystem moisture gradient (CEMG) of all four ecosystems considered together. An elevation transect of three sampling plots was monitored within each ecosystem and soil samples were collected from these plots and from existing experimental precipitation manipulations within each ecosystem once in fall of 2009 and three times each in 2010 and 2011. Mites and nematodes were sorted to trophic groups and analyzed to determine community responses to changes in soil moisture availability. We found that while both mites and nematodes increased with available soil moisture across the CEMG, within individual ecosystems, increases in soil moisture resulted in decreases to nematode communities at all but the arid grassland ecosystem; mites showed no responses at any ecosystem. In addition, we found changes in proportional abundances of mite and nematode trophic groups as soil moisture increased within individual ecosystems, which may result in shifts within soil food webs with important consequences for ecosystem functioning. We suggest that communities of soil animals at local scales may respond predictably to changes in moisture availability regardless of ecosystem type but that additional factors, such as climate variability, vegetation composition, and soil properties may influence this relationship over larger scales.

}, keywords = {LTER-KNZ}, doi = {10.1111/gcb.12522}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.12522}, author = {Sylvain, Z.A. and Wall, D.H and Cherwin, K.L and Peters, D.P.C and Reichmann, L.G and Sala, O.E.} } @article {KNZ001556, title = {Stomatal responses to changes in vapor pressure deficit reflect tissue-specific differences in hydraulic conductance}, journal = {Plant, Cell and Environment}, volume = {37}, year = {2014}, pages = {132 -139}, abstract = {

The vapor pressure deficit (D) of the atmosphere can negatively affect plant growth as plants reduce stomatal conductance to water vapor (gwv) in response to increasing D, limiting the ability of plants to assimilate carbon. The sensitivity of gwv to changes in D varies among species and has been correlated with the hydraulic conductance of leaves (Kleaf), but the hydraulic conductance of other tissues has also been implicated in plant responses to changing D. Among the 19 grass species, we found that Kleaf was correlated with the hydraulic conductance of large longitudinal veins (Klv, r2\ =\ 0.81), but was not related to Kroot (r2\ =\ 0.01). Stomatal sensitivity to D was correlated with Kleaf relative to total leaf area (r2\ =\ 0.50), and did not differ between C3 and C4 species. Transpiration (E) increased in response to D, but 8 of the 19 plants showed a decline in E at high D, indicative of an \‘apparent feedforward\’ response. For these individuals, E began to decline at lower values of D in plants with low Kroot (r2\ =\ 0.72). These results show the significance of both leaf and root hydraulic conductance as drivers of plant responses to evaporative demand.

}, keywords = {LTER-KNZ}, doi = {10.1111/pce.12137}, url = {https://onlinelibrary.wiley.com/doi/full/10.1111/pce.12137}, author = {Ocheltree, T.W. and Jesse B. Nippert and Prasad, P.V.V.} } @article {KNZ001626, title = {You are not always what we think you eat: selective assimilation across multiple whole-stream isotopic tracer studies}, journal = {Ecology}, volume = {95}, year = {2014}, pages = {2757 -2767}, abstract = {

Analyses of 21 15N stable isotope tracer experiments, designed to examine food web dynamics in streams around the world, indicated that the isotopic composition of food resources assimilated by primary consumers (mostly invertebrates) poorly reflected the presumed food sources. Modeling indicated that consumers assimilated only 33\–50\% of the N available in sampled food sources such as decomposing leaves, epilithon, and fine particulate detritus over feeding periods of weeks or more. Thus, common methods of sampling food sources consumed by animals in streams do not sufficiently reflect the pool of N they assimilate. Isotope tracer studies, combined with modeling and food separation techniques, can improve estimation of N pools in food sources that are assimilated by consumers. Food web studies that use putative food samples composed of actively cycling (more readily assimilable) and refractory (less assimilable) N fractions may draw erroneous conclusions about diets, N turnover, and trophic linkages of consumers. By extension, food web studies using stoichiometric or natural abundance approaches that rely on an accurate description of food-source composition could result in errors when an actively cycling pool that is only a fraction of the N pool in sampled food resources is not accounted for.

}, keywords = {LTER-KNZ}, doi = {10.1890/13-2276.1}, url = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/13-2276.1}, author = {W. K. Dodds and Scott. L. Collins and Hamilton, S.K. and Tank, J.L. and Johnson, S. and Webster, J.R. and Simon, K.S. and M.R. Whiles and Rantala, H.M. and W.H. McDowell and Peterson, S.D. and Riis, T. and Crenshaw, C.L. and Thomas, S.A. and Kristensen, P.B. and Cheever, B.M. and Flecker, A.S. and Griffiths, N.A. and Crowl, T. and Rosi-Marshall, E.J. and El-Sabaawi, R. and Marti, E.} } @article {KNZ001523, title = {Estimating aboveground net primary productivity of the tallgrass prairie ecosystem of the Central Great Plains using AVHRR NDVI}, journal = {International Journal of Remote Sensing}, volume = {34}, year = {2013}, pages = {3717 -3735}, abstract = {

Above-ground net primary productivity (ANPP) is indicative of an ecosystem\&$\#$39;s ability to capture solar energy and convert it to organic carbon (or biomass), which may be used by consumers or decomposers, or stored in the form of living and nonliving organic matter. Annual and interannual variation in ANPP is often linked to climate dynamics and anthropogenic influences, such as fertilization, irrigation, above-ground biomass harvest, and so on. The Central Great Plains grasslands occupy over 1.5 million km2 and are a primary resource for livestock production in North America. The tallgrass prairies are the most productive grasslands in this region, and the Flint Hills of North America represent the largest contiguous area of unploughed tallgrass prairie (1.6 million ha). Measurements of ANPP are of critical importance to the proper management and understanding of climatic and anthropogenic influences on tallgrass prairie. Yet, accurate, detailed, and systematic measurements of ANPP over large geographic regions do not exist for this ecosystem. For these reasons, this study was conducted to investigate the use of the normalized difference vegetation index (NDVI) to model ANPP of the tallgrass prairie. Many studies have established a positive relationship between the NDVI and ANPP, but the strength of this relationship is influenced by vegetation types and can vary significantly from year to year depending on land use and climatic conditions. The goal of this study was to develop a robust model using the Advanced Very High Resolution Radiometer (AVHRR) biweekly NDVI values to predict tallgrass ANPP. This study was conducted using ANPP measurements from a watershed within the Konza Prairie Biological Station (KPBS) as the primary study area, with additional measurements from the Rannells Flint Hills Prairie Preserve (RFHPP) and biennial ANPP measurements by Kansas State University (KSU) students from tallgrass areas near Manhattan, Kansas. Data from the primary study site covered the period of 1989\–2005. The optimal period for estimating ANPP using AVHRR NDVI composite data sets was found to be late July. The Tallgrass ANPP Model (TAM) explained 54\% (coefficient of determination, R 2 = 0.54, p \< 0.001) of the year-to-year variation in ANPP. The creation of 1.0 km \× 1.0 km resolution ANPP maps for a four-county (\∼7000 ha) area for years 1989\–2007 showed considerable variation in annual and interannual ANPP spatial patterns, suggesting complex interactions among factors influencing ANPP spatially and temporally.

}, keywords = {LTER-KNZ}, doi = {10.1080/01431161.2012.757376}, url = {https://doi.org/10.1080/01431161.2012.757376}, author = {An, N. and Price, K.P. and John M. Blair} } @article {KNZ001591, title = {The exaggerated begging behaviour of an obligate avian brood parasite is shared with a nonparasitic close relative}, journal = {Animal Behaviour}, volume = {86}, year = {2013}, pages = {529 -536}, abstract = {Offspring signalling models predict that the begging displays of obligate brood parasites are more intense than nonparasitic species because parasitic young are never reared by their genetic parents and often compete against unrelated host young during development. The brown-headed cowbird, Molothrus ater, has been described as having exaggerated begging relative to nonparasitic species, but an effective test of this idea is lacking because previous studies have not controlled for evolutionary history while simultaneously standardizing rearing conditions. We quantified the begging intensity of cowbirds and the closely related, nonparasitic red-winged blackbird, Agelaius phoeniceus, when both species experienced identical rearing conditions in two distinct nest environments: reared alone by a small cowbird host, or reared with two host young by a moderate-sized cowbird host. Against theoretical predictions, we found that in both nest environments four components of the cowbird begging display were similar to (or less intense than) blackbird begging displays (i.e. latency to beg, begging score, call rate and call amplitude) when nestlings were tested across a gradient of short-term need. Our results provide the first experimental evidence that a closely related, yet nonparasitic, species shares an exaggerated begging display with a brood-parasitic species when reared under conditions typically experienced by parasitic offspring. We discuss three nonexclusive explanations for our findings: (1) relatedness among cowbird nestmates reduced cowbird begging intensity (kin selection hypothesis), (2) reduced body condition of blackbirds elevated their begging intensity (body condition hypothesis) and (3) intense competition in blackbird nest environments led to increased blackbird begging intensity (competitive environment hypothesis).}, keywords = {LTER-KNZ, Agelaius phoeniceus, begging, brood parasitism, brown-headed cowbird, Molothrus ater, offspring signalling, red-winged blackbird}, doi = {10.1016/j.anbehav.2013.06.004}, url = {http://dx.doi.org/10.1016/j.anbehav.2013.06.004}, author = {Rivers, J.W. and M.A. Blundell and Loughin, T.M. and Peer, B.D. and Rothstein, S.I.} } @proceedings {KNZ001604, title = {Fungal community responses to discrete precipitation pulses under altered rainfall intervals}, volume = {103}, year = {2013}, pages = {182 -}, keywords = {LTER-KNZ}, author = {A. Jumpponen and Lydia H. Zeglin and David, M. and Prestat, E. and Brown, S. and Dvornik, J. and Lothamer, K. and Hettich, R. and Jansson, J. and C. W. Rice and Tringe, S. and Myrold, D.D.} } @article {KNZ001619, title = {Invertebrates, ecosystem services and climate change}, journal = {Biological Reviews}, volume = {88}, year = {2013}, pages = {327 -348}, abstract = {

The sustainability of ecosystem services depends on a firm understanding of both how organisms provide these services to humans and how these organisms will be altered with a changing climate. Unquestionably a dominant feature of most ecosystems, invertebrates affect many ecosystem services and are also highly responsive to climate change. However, there is still a basic lack of understanding of the direct and indirect paths by which invertebrates influence ecosystem services, as well as how climate change will affect those ecosystem services by altering invertebrate populations. This indicates a lack of communication and collaboration among scientists researching ecosystem services and climate change effects on invertebrates, and land managers and researchers from other disciplines, which becomes obvious when systematically reviewing the literature relevant to invertebrates, ecosystem services, and climate change. To address this issue, we review how invertebrates respond to climate change. We then review how invertebrates both positively and negatively influence ecosystem services. Lastly, we provide some critical future directions for research needs, and suggest ways in which managers, scientists and other researchers may collaborate to tackle the complex issue of sustaining invertebrate-mediated services under a changing climate.

}, keywords = {LTER-KNZ, Biodiversity, bioindicator species, Climate change, ecosystem engineers, ecosystem services, insects, invertebrates, sustainability}, doi = {10.1111/brv.12002}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/brv.12002}, author = {Prather, C.M. and Pelini, S. and Laws, A. and Rivest, E. and Woltz, M. and Bloch, C.P. and Del Toro, I. and Ho, Chuan-Kai. and Kominoski, J. and Newbold, T.A.S. and Parsons, S. and Anthony Joern} } @article {KNZ001617, title = {Life history traits associated with body size covary along a latitudinal gradient in a generalist grasshopper}, journal = {Oecologia}, volume = {174}, year = {2013}, pages = {379 -391}, abstract = {

Animal body size often varies systematically along latitudinal gradients, where individuals are either larger or smaller with varying season length. This study examines ecotypic responses by the generalist grasshopper Melanoplus femurrubrum (Orthoptera: Acrididae) in body size and covarying, physiologically based life history traits along a latitudinal gradient with respect to seasonality and energetics. The latitudinal compensation hypothesis predicts that smaller body size occurs in colder sites when populations must compensate for time constraints due to short seasons. Shorter season length requires faster developmental and growth rates to complete life cycles in one season. Using a common garden experimental design under laboratory conditions, we examined how grasshopper body size, consumption, developmental time, growth rate and metabolism varied among populations collected along an extended latitudinal gradient. When reared at the same temperature in the lab, individuals from northern populations were smaller, developed more rapidly, and showed higher growth rates, as expected for adaptations to shorter and generally cooler growing seasons. Temperature-dependent, whole organism metabolic rate scaled positively with body size and was lower at northern sites, but mass-specific standard metabolic rate did not differ among sites. Total food consumption varied positively with body size, but northern populations exhibited a higher mass-specific consumption rate. Overall, compensatory life history responses corresponded with key predictions of the latitudinal compensation hypothesis in response to season length.

}, keywords = {LTER-KNZ, acrididae, Development time, Growth rate, Latitudinal compensation hypothesis, Melanoplus femurrubrum}, doi = {10.1007/s00442-013-2785-6}, url = {https://link.springer.com/article/10.1007\%2Fs00442-013-2785-6}, author = {Parsons, S. and Anthony Joern} } @article {KNZ001790, title = {Predicting invasion in grassland ecosystems: is exotic dominance the real embarrassment of richness?}, journal = {Global Change Biology}, volume = {19}, year = {2013}, pages = {3677 - 3687}, abstract = {

Invasions have increased the size of regional species pools, but are typically assumed to reduce native diversity. However, global-scale tests of this assumption have been elusive because of the focus on exotic species richness, rather than relative abundance. This is problematic because low invader richness can indicate invasion resistance by the native community or, alternatively, dominance by a single exotic species. Here, we used a globally replicated study to quantify relationships between exotic richness and abundance in grass-dominated ecosystems in 13 countries on six continents, ranging from salt marshes to alpine tundra. We tested effects of human land use, native community diversity, herbivore pressure, and nutrient limitation on exotic plant dominance. Despite its widespread use, exotic richness was a poor proxy for exotic dominance at low exotic richness, because sites that contained few exotic species ranged from relatively pristine (low exotic richness and cover) to almost completely exotic-dominated ones (low exotic richness but high exotic cover). Both exotic cover and richness were predicted by native plant diversity (native grass richness) and land use (distance to cultivation). Although climate was important for predicting both exotic cover and richness, climatic factors predicting cover (precipitation variability) differed from those predicting richness (maximum temperature and mean temperature in the wettest quarter). Herbivory and nutrient limitation did not predict exotic richness or cover. Exotic dominance was greatest in areas with low native grass richness at the site- or regional-scale. Although this could reflect native grass displacement, a lack of biotic resistance is a more likely explanation, given that grasses comprise the most aggressive invaders. These findings underscore the need to move beyond richness as a surrogate for the extent of invasion, because this metric confounds monodominance with invasion resistance. Monitoring species\&$\#$39; relative abundance will more rapidly advance our understanding of invasions.

}, keywords = {LTER-KNZ}, doi = {10.1111/gcb.12370}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.12370}, author = {Seabloom, E.W. and E.T. Borer and Buckley, Y. and Cleland, E.E. and Davies, K. and Firn, J. and Harpole, W.S. and Hautier, Y. and Lind, E. and MacDougall, A. and Orrock, J.L. and Prober, S.M. and P. Adler and J. Alberti and Anderson, M.T. and J.D. Bakker and L.A. Biederman and D.M. Blumenthal and C.S. Brown and Brudvig, L.A. and Caldeira, M. and Chu, C. and Crawley, M.J. and Daleo, P. and Damschen, E.I. and D{\textquoteright}Antonio, C.M. and DeCrappeo, N.M. and Dickman, C.R. and G. Du and Fay, P.A. and Frater, P. and Gruner, D.S. and Hagenah, N. and Hector, A. and Helm, A. and Hillebrand, H. and Hofmockel, K.S. and Humphries, H.C. and Iribarne, O. and Jin, V.L. and Kay, A. and Kirkman, K.P. and Klein, J.A. and Knops, J.M.H. and Kimberly J. La Pierre and L. Ladwig and Lambrinos, J.G. and Leakey, A.D.B. and Li, Q. and Li, W. and McCulley, R. and Melbourne, B. and Mitchell, C.E. and Joslin L. Moore and J.W. Morgan and Mortensen, B. and O{\textquoteright}Halloran, L.R. and P{\"a}rtel, M. and Pascual, J and Pyke, D.A. and A. Risch and Salguero-Gomez, R. and Sankaran, M. and Schuetz, M. and Simonsen, A. and M.D. Smith and Stevens, C. and Sullivan, L. and Wardle, G.M. and Wolkovich, E.M. and Wragg, P.D. and Wright, J. and Yang, L.} } @article {KNZ001502, title = {Changes in stomatal conductance along grass blades reflect changes in leaf structure}, journal = {Plant Cell and Environment}, volume = {35}, year = {2012}, pages = {1040 -1049}, abstract = {

Identifying the consequences of grass blade morphology (long, narrow leaves) on the heterogeneity of gas exchange is fundamental to an understanding of the physiology of this growth form. We examined acropetal changes in anatomy, hydraulic conductivity and rates of gas exchange in five grass species (including C3 and C4 functional types). Both stomatal conductance and photosynthesis increased along all grass blades despite constant light availability. Hydraulic efficiency within the xylem remained constant along the leaf, but structural changes outside the xylem changed in concert with stomatal conductance. Stomatal density and stomatal pore index remained constant along grass blades but interveinal distance decreased acropetally resulting in a decreased path length for water movement from vascular bundle to stomate. The increase in stomatal conductance was correlated with the decreased path length through the leaf mesophyll. A strong correlation between the distance from vascular bundles to stomatal pores and stomatal conductance has been identified across species; our results suggest this relationship also exists within individual leaves.

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1365-3040.2011.02470.x}, url = {https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-3040.2011.02470.x}, author = {Ocheltree, T.W. and Jesse B. Nippert and Prasad, P.V.V.} } @article {KNZ001440, title = {Climate change alters growing season flux dynamics in mesic grasslands}, journal = {Theoretical and Applied Climatology}, volume = {107}, year = {2012}, pages = {427 -440}, abstract = {

Changing climate could affect the functioning of grassland ecosystems through variation in climate forcings and by altering the interactions of forcings with ecological processes. Both the short and long-term effects of changing forcings and ecosystem interactions are a critical part of future impacts to ecosystem ecology and hydrology. To explore these interactions and identify possible characteristics of climate change impacts to mesic grasslands, we employ a low-dimensional modeling framework to assess the IPCC A1B scenario projections for the Central Plains of the United States; forcings include increased precipitation variability, increased potential evaporation, and earlier growing season onset. These forcings are also evaluated by simulations of vegetation photosynthetic capacity to explore the seasonal characteristics of the vegetation carbon assimilation response for species at the Konza Prairie in North Central Kansas, USA. The climate change simulations show decreases in mean annual soil moisture and and carbon assimilation and increased variation in water and carbon fluxes during the growing season. Simulations of the vegetation response show increased variation at the species-level instead of at a larger class scale, with important heterogeneity in how individual species respond to climate forcings. Understanding the drivers and relationships behind these ecosystem responses is important for understanding the likely scale of climate change impacts and for exploring the mechanisms shaping growing season dynamics in grassland ecosystems.

}, keywords = {LTER-KNZ, ecohydrology, Konza Prairie, Low-dimensional modeling, Nonlinear interactions, Soil moisture feedback}, doi = {10.1007/s00704-011-0484-y}, url = {https://link.springer.com/article/10.1007\%2Fs00704-011-0484-y}, author = {Petrie, M.D. and N. Brunsell and Jesse B. Nippert} } @article {KNZ001519, title = {Comparison of eggshell porosity and estimated gas flux between the brown-headed cowbird and two common hosts}, journal = {Journal of Avian Biology}, volume = {43}, year = {2012}, pages = {486 -490}, abstract = {

The brown-headed cowbird Molothrus ater is a brood-parasite that lays eggs in nests of a wide range of host species, including the closely-related red-winged blackbird Agelaius phoeniceus and the dickcissel Spiza americana. Although cowbird eggs have accelerated development and hatch sooner than similar-sized host eggs, this development takes place within a thickened eggshell that could impede gas flux to the developing embryo. We tested the hypothesis that the accelerated development of the cowbird embryo relative to hosts is enabled by an increase in eggshell porosity that allows increased fluxes of respiratory gases to and from the developing embryo. We found cowbird eggshell thickness was significantly greater than the eggshells of these two common hosts. Although the number of pores per egg was similar among all three species, the total pore area per egg in cowbirds was significantly greater than that of either host, despite having a smaller eggshell surface area than the red-winged blackbird. Cowbird egg pore area was 1.9\×larger than that of the red-winged blackbird. Cowbird eggshells had a significantly greater gas flux than those of the red-winged blackbird and the dickcissel. When conductance was normalized to published values of egg mass, cowbird eggs had a higher mass-specific conductance than red-winged blackbird or dickcissel eggs. These results are consistent with the hypothesis that the rapid development of brown-headed cowbird embryos is facilitated by increased eggshell porosity, and that changes in eggshell porosity represent an adaptation that enables cowbird eggs to hatch earlier than equivalently-sized host eggs.

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1600-048X.2012.05705.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1600-048X.2012.05705.x}, author = {Jaeckle, W.B. and Kiefer, M. and Childs, B. and Harper, R.G. and Rivers, J.W. and Peer, B.D.} } @article {KNZ001879, title = {Controls on Soil Organic Carbon Stocks and Turnover Among North American Ecosystems}, journal = {Ecosystems}, volume = {15}, year = {2012}, pages = {604 - 615}, keywords = {LTER-KNZ}, issn = {1432-9840}, doi = {10.1007/s10021-012-9534-2}, url = {http://link.springer.com/10.1007/s10021-012-9534-2}, author = {Frank, Douglas A. and Pontes, Alyssa W. and McFarlane, Karis J.} } @article {KNZ001511, title = {Dissolved organic matter in headwater streams: compositional variability across climatic regions of North America}, journal = {Geochimica et Cosmochimica Acta}, volume = {94}, year = {2012}, pages = {95 -108}, abstract = {

Dissolved organic matter (DOM) represents the largest organic matter pool in freshwater systems, but much of it remains molecularly uncharacterized. Although freshwater systems cover only a small area of the earth\’s surface, inland waters are an important component of the global carbon cycle. The traditional idea that rivers are simply conduits for refractory carbon delivery to coastal areas is inconsistent with carbon flux estimates, and streams have been shown to serve as reactors for DOM cycling. The overall quality of DOM, and its associated reactivity, can be related to its chemical composition and molecular structure. However, the variability of DOM composition in freshwater ecosystems, particularly in headwater streams, is poorly characterized. Detailed molecular studies of DOM from small streams across climatic regions, which could provide critical information regarding carbon dynamics on a more global scale, have not been performed. To address these issues, this study applies a multi-method analytical approach in an attempt to assess molecular characteristics of DOM and ultrafiltered DOM (UDOM) in headwater streams from different climatic regions in North America. In general terms the chemical and molecular characteristics of UDOM from six different biomes were determined in unsurpassed detail to feature some clear general similarities but also specific differences. While the degree of similarity is remarkable, and suggests similar source strengths, such as soil-derived organic matter and/or similar diagenetic degradation processes for DOM from vastly different environments, each sample was clearly unique in its overall composition, featuring some distinct molecular patterns for at least one or more of the analytical determinations. Molecular and compositional differences of DOM from headwater streams should result from variations in DOM sources and localized environmental conditions, and consequently feature different photo- and bio-reactivity and associated re-mineralization potentials during fluvial transport. Such knowledge could assist in predicting the consequences of global change and its relationship to global carbon cycling.

}, keywords = {LTER-KNZ}, doi = {10.1016/j.gca.2012.06.031}, url = {https://www.sciencedirect.com/science/article/pii/S0016703712004097?via\%3Dihub}, author = {Jaff{\'e}, R. and Yamashita, Y. and Maie, N. and Cooper, W.T. and Dittmar, T. and W. K. Dodds and Jones, J.B. and Myoshi, T. and Ortiz-Zayas, J.R. and Podgorski, D.C. and Watanabe, A.} } @article {KNZ001623, title = {The effect of experimental warming and precipitation change on proteolytic enzyme activity: positive feedbacks to nitrogen availability are not universal}, journal = {Global Change Biology}, volume = {18}, year = {2012}, pages = {2617 -2625}, abstract = {

Nitrogen regulates the Earth\&$\#$39;s climate system by constraining the terrestrial sink for atmospheric CO2. Proteolytic enzymes are a principal driver of the within-system cycle of soil nitrogen, yet there is little to no understanding of their response to climate change. Here, we use a single methodology to investigate potential proteolytic enzyme activity in soils from 16 global change experiments. We show that regardless of geographical location or experimental manipulation (i.e., temperature, precipitation, or both), all sites plotted along a single line relating the response ratio of potential proteolytic activity to soil moisture deficit, the difference between precipitation and evapotranspiration. In particular, warming and reductions in precipitation stimulated potential proteolytic activity in mesic sites \– temperate and boreal forests, arctic tundra \– whereas these manipulations suppressed potential activity in dry grasslands. This study provides a foundation for a simple representation of the impacts of climate change on a central component of the nitrogen cycle.

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1365-2486.2012.02685.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2486.2012.02685.x}, author = {Brozostek, E.R. and John M. Blair and Dukes, J.S. and Frey, S.D. and Hobbie, S.E. and Melillo, J.M. and Mitchell, R.J. and Pendall, E.S. and P.B. Reich and Shaver, G.R. and Stefanskii, A. and Tjoelker, M.G. and Finzi, A.C.} } @article {KNZ001407, title = {Effects of rangeland management on the site occupancy dynamics of prairie-chickens in a protected prairie preserve}, journal = {Journal of Wildlife Management}, volume = {76}, year = {2012}, pages = {38 -47}, abstract = {

We investigated the site occupancy dynamics of greater prairie-chickens at Konza Prairie Biological Station, a protected site in northeastern Kansas that is managed for ecological research. We surveyed the site during mid-Mar to mid-May, 1981\–2008, and recorded detections of birds in a grid of 6.3\ ha survey plots (n\ =\ 187 plots). We used multiseason occupancy models to estimate the probabilities of occupancy (ψ) and detection (p), and tested whether land cover in woody vegetation, and land use with prescribed fire or grazing management influenced the dynamic processes of site colonization and local extinction. Probability of detection per site was consistently \<1 and varied among years (p\ =\ 0.12\–0.82). Site occupancy of prairie-chickens declined 40\% over the study period from a high of ψ\ =\ 0.19\ \±\ 0.02\ SE in 1981 to a low of 0.11\ \±\ 0.03 in 2008, despite protection from disturbance at leks and losses to harvest. We found that different sets of environmental factors impacted the probabilities of colonization and local extinction. Probability of colonization for an unoccupied site was negatively associated with the proportion of site occupied by woodland cover (β\ =\ \−1.25), and was lower for grazed sites (β\ =\ \−0.62). In contrast, probability of local extinction was affected by a weak interaction between grazing and average frequency of prescribed fire (β\ =\ \−1.01), but model-averaged slope coefficients were not statistically different than 0. To conserve prairie-chickens, we recommend prairies be managed with combinations of prescribed fire and grazing that maintain a heterogeneous mosaic of prairie habitats, while preventing woody encroachment. To assess biotic responses to land management practices, field sampling should be based on occupancy models or similar techniques that account for imperfect detection. \© 2011 The Wildlife Society.

}, keywords = {LTER-KNZ, colonization, detection probabilities, greater prairie-chicken, Kansas;Konza Prairie Biological Station, local extinction, occupancy modeling, Tympanuchus cupido}, doi = {10.1002/jwmg.237}, url = {https://wildlife.onlinelibrary.wiley.com/doi/abs/10.1002/jwmg.237}, author = {McNew, L.B. and Prebyl, T.J. and Sandercock, B.K.} } @phdthesis {KNZ001477, title = {Growth and survival during drought: The link between hydraulic architecture and drought tolerance in grasses}, volume = {PhD Dissertation}, year = {2012}, pages = {1 -1117}, school = {Kansas State University}, type = {Ph.D. Thesis}, address = {Manhattan, KS}, abstract = {

The pathway for the movement of water through plants, from the soil matrix to the atmosphere, constitutes the hydraulic architecture of a plant. The linkage between the hydraulic architecture of woody plants and drought tolerance has received considerable attention, but much less work has been done on grasses. I investigated the linkage between the hydraulic architecture of grasses to physiological patterns of water use across a range of species and conditions. The rate of stomatal conductance (g[subscript]s) and photosynthesis (A) increased acropetally along the leaves of 5 grass species, which is a unique feature of this growth form. The internal structure of leaves also changed acropetally in order to minimize the pressure gradient across the mesophyll that would otherwise occur as a result of increasing g[subscript]s. The resistance to water movement through the mesophyll represented 80-90\% of leaf resistance in six genotypes of Sorghum bicolor L. (Moench). This resistance was most important in controlling g[subscript]s and A when water was readily available, but as soil-moisture decreased it was the efficient transport of water through the xylem that was most important in maintaining plant function. I also investigated the relationship between hydraulic architecture and stomatal responses of grasses to increasing Vapor Pressure Deficit (D). Grasses with a larger proportion of their hydraulic resistance within the xylem were less sensitive to increasing D and plants with high root conductance maintained higher rates of gas exchange D increased. Finally, I investigated the tolerance of grasses to extreme drought events to test if there was a trade-off between drought tolerance and growth in grasses. Plants with drought tolerant leaf traits typically sacrificed the ability to move water efficiently through their leaves. Having drought tolerant leaves did not limit the plants ability to have high rates of gas exchange, and, in fact, the most drought tolerant plants had the high rates of g[subscript]s when expressed on a mass basis. Leaf-level drought tolerance did contribute to species\’ occurrence, as the drought intolerant species I studied are not commonly found in low precipitation systems. The results presented here highlight the importance of studying the hydraulic architecture of plants to provide a better understanding of what controls plant function across a range of environmental conditions.

}, keywords = {LTER-KNZ, Drought Tolerance, Grass Anatomy, Grass Physiology, Plant Hydraulic Architecture, Stomatal Conductance}, url = {http://hdl.handle.net/2097/13803}, author = {Ocheltree, T.W.} } @article {KNZ001497, title = {Incorporating clonal growth form clarifies the role of plant height in response to nitrogen addition}, journal = {Oecologia}, volume = {169}, year = {2012}, pages = {1053 -1062}, abstract = {

Nutrient addition to grasslands consistently causes species richness declines and productivity increases. Competition, particularly for light, is often assumed to produce this result. Using a long-term dataset from North American herbaceous plant communities, we tested whether height and clonal growth form together predict responses to fertilization because neither trait alone predicted species loss in a previous analysis. Species with a tall-runner growth form commonly increased in relative abundance in response to added nitrogen, while short species and those with a tall-clumped clonal growth form often decreased. The ability to increase in size via vegetative spread across space, while simultaneously occupying the canopy, conferred competitive advantage, although typically only the abundance of a single species within each height-clonal growth form significantly responded to fertilization in each experiment. Classifying species on the basis of two traits (height and clonal growth form) increases our ability to predict species responses to fertilization compared to either trait alone in predominantly herbaceous plant communities.

}, keywords = {LTER-KNZ, Clonal growth, Competition, grassland, Nitrogen addition, productivity}, doi = {10.1007/s00442-012-2264-5}, url = {https://link.springer.com/article/10.1007\%2Fs00442-012-2264-5}, author = {Gough, L. and Gross, K.L. and Cleland, E.E. and Clark, C.M. and Scott. L. Collins and Fargione, J.E. and Pennings, S.C. and K.N. Suding} } @booklet {KNZ001539, title = {Long-term trends in ecological systems: a basis for understanding responses to global change. USDA Agriculture Research Service Publication, Technical Bulletin 1931. Washington, D.C}, year = {2012}, abstract = {

Peters, D.P.C., C.M. Laney, A.E. Lugo, et al. 2013. Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change. U.S. Department of Agriculture, Technical Bulletin Number 1931. The EcoTrends Editorial Committee sorted through vast amounts of historical and ongoing data from 50 ecological sites in the continental United States including Alaska, several islands, and Antarctica to present in a logical format the variables commonly collected. This report presents a subset of data and variables from these sites and illustrates through detailed examples the value of comparing longterm data from different ecosystem types. This work provides cross-site comparisons of ecological responses to global change drivers, as well as longterm trends in global change drivers and responses at site and continental scales. Site descriptions and detailed data also are provided in the appendix section.

}, keywords = {LTER-KNZ, atmospheric chemistry, Climate change, cross-site comparisons, disturbance, ecological response, ecology, ecosystem, EcoTrends, experimental forests, global change, human demography, human population growth, Long Term Ecological Research (LTER), long-term datasets, Precipitation, rangeland, rangeland research stations, surface water chemistry}, author = {Peters, D.P.C. and Laney, C.M. and Lugo, A.E. and Scott. L. Collins and Driscoll, C.T. and Groffman, P.M. and Grove, J.M. and Alan K. Knapp and Kratz, T.K. and Ohman, M.D. and Waide, R.B. and Yao, J.} } @article {KNZ001396, title = {The role of precipitation variability on the ecohydrology of grasslands}, journal = {Ecohydrology}, volume = {5}, year = {2012}, pages = {337 -345}, abstract = {

Precipitation event timing and magnitude are important drivers of ecosystem processes and are instrumental in creating landscape heterogeneity. Ecosystems respond to precipitation and other driving variables at different spatial and temporal scales, which complicates understanding of the relationships that govern ecosystem conditions. To better characterize the ecosystem response, we present a low-dimensional framework for simulating the influence of precipitation event timing and magnitude on grassland ecosystems, with particular focus on characterizing the temporal sensitivity of water and carbon fluxes to climate forcings and the feedback of water and carbon on soil moisture availability. Results show variation in daily through seasonal sensitivity of ecosystem water and carbon fluxes and identifies the way these sensitivities change at daily to annual timescales to shape long-term ecosystem states. This provides for a better understanding of the nonlinearities inherent to ecosystem interactions during the growing season and provides assessment of the extent that precipitation variance has on grassland functioning and heterogeneity. Copyright \© 2011 John Wiley \& Sons, Ltd.

}, keywords = {LTER-KNZ}, doi = {10.1002/eco.224}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/eco.224}, author = {Petrie, M.D. and N. Brunsell} } @article {KNZ001484, title = {Sensitivity of mean annual primary production to precipitation}, journal = {Global Change Biology}, volume = {18}, year = {2012}, pages = {2246 -2255}, abstract = {

In many terrestrial ecosystems, variation in aboveground net primary production (ANPP) is positively correlated with variation in interannual precipitation. Global climate change will alter both the mean and the variance of annual precipitation, but the relative impact of these changes in precipitation on mean ANPP remains uncertain. At any given site, the slope of the precipitation-ANPP relationship determines the sensitivity of mean ANPP to changes in mean precipitation, whereas the curvature of the precipitation-ANPP relationship determines the sensitivity of ANPP to changes in precipitation variability. We used 58 existing long-term data sets to characterize precipitation-ANPP relationships in terrestrial ecosystems and to quantify the sensitivity of mean ANPP to the mean and variance of annual precipitation. We found that most study sites have a nonlinear, saturating relationship between precipitation and ANPP, but these nonlinearities were not strong. As a result of these weak nonlinearities, ANPP was nearly 40 times more sensitive to precipitation mean than variance. A 1\% increase in mean precipitation caused a \−0.2\% to 1.8\% change in mean ANPP, with a 0.64\% increase on average. Sensitivities to precipitation mean peaked at sites with a mean annual precipitation near 500 mm. Changes in species composition and increased intra-annual precipitation variability could lead to larger ANPP responses to altered precipitation regimes than predicted by our analysis.

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1365-2486.2012.02687.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2486.2012.02687.x}, author = {Hsu, J.S. and Powell, J. and P. Adler} } @article {KNZ001473, title = {Stability of tallgrass prairie during a 19-year increase in growing season precipitation}, journal = {Functional Ecology}, volume = {26}, year = {2012}, pages = {1450 - 1459}, keywords = {LTER-KNZ}, doi = {10.1111/j.1365-2435.2012.01995.x}, url = {https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2435.2012.01995.x}, author = {Scott. L. Collins and Koerner, S.E. and Plaut, J.A. and Okie, J.G. and Brese, D. and Calabrese, L.B. and Carvajal, A. and Evanse, R.J. and Nonaka, E.} } @article {KNZ001510, title = {Surprises and insights from long-term aquatic datasets and experiments}, journal = {BioScience}, volume = {62}, year = {2012}, pages = {709 -721}, abstract = {

Long-term research on freshwater ecosystems provides insights that can be difficult to obtain from other approaches. Widespread monitoring of ecologically relevant water-quality parameters spanning decades can facilitate important tests of ecological principles. Unique long-term data sets and analytical tools are increasingly available, allowing for powerful and synthetic analyses across sites. Long-term measurements or experiments in aquatic systems can catch rare events, changes in highly variable systems, time-lagged responses, cumulative effects of stressors, and biotic responses that encompass multiple generations. Data are available from formal networks, local to international agencies, private organizations, various institutions, and paleontological and historic records; brief literature surveys suggest much existing data are not synthesized. Ecological sciences will benefit from careful maintenance and analyses of existing long-term programs, and subsequent insights can aid in the design of effective future long-term experimental and observational efforts. Long-term research on freshwaters is particularly important because of their value to humanity.

}, keywords = {LTER-KNZ, data, freshwater, lakes, long term, streams}, doi = {10.1525/bio.2012.62.8.4}, url = {https://academic.oup.com/bioscience/article/62/8/709/244214}, author = {W. K. Dodds and Robinson, C.T. and Gaiser, E.E. and Hansen, G.J.A. and Powell, H. and Smith, J.M. and Morse, N.B. and Johnson, S.L. and Gregory, S.V. and Bell, T. and Kratz, T.K. and W.H. McDowell} } @article {KNZ001455, title = {Abundance of introduced species at home predicts abundance away in herbaceous communities}, journal = {Ecology Letters}, volume = {14}, year = {2011}, pages = {274 -281}, keywords = {LTER-KNZ}, doi = {10.1111/j.1461-0248.2010.01584.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1461-0248.2010.01584.x}, author = {Firn, J. and Joslin L. Moore and MacDougall, A.S. and E.T. Borer and Seabloom, E.W. and HilleRisLambers, J. and Harpole, W.S. and Cleland, E.E. and C.S. Brown and Knops, J.M.H. and Prober, S.M. and Pyke, D.A. and Farrell, K.A. and J.D. Bakker and O{\textquoteright}Halloran, L.R. and P. Adler and Scott. L. Collins and D{\textquoteright}Antonio, C.M. and Crawley, M.J. and Wolkovich, E.M. and Kimberly J. La Pierre and Melbourne, B.A. and Hautier, Y. and J.W. Morgan and Leakey, A.D.B. and Kay, A.D. and McCulley, R. and Davies, K.F. and Stevens, C.J. and Chu, C. and Holl, K.D. and Klein, J.A. and Fay, P.A. and Hagenah, N. and Kirkman, K.P. and Buckley, Y.M.} } @article {KNZ001392, title = {Complexity in climate change impacts: An analytical framework for effects mediated by plant disease}, journal = {Plant Pathology}, volume = {60}, year = {2011}, pages = {15 -30}, abstract = {

The impacts of climate change on ecosystem services are complex in the sense that effective prediction requires consideration of a wide range of factors. Useful analysis of climate-change impacts on crops and native plant systems will often require consideration of the wide array of other biota that interact with plants, including plant diseases, animal herbivores, and weeds. We present a framework for analysis of complexity in climate-change effects mediated by plant disease. This framework can support evaluation of the level of model complexity likely to be required for analysing climate-change impacts mediated by disease. Our analysis incorporates consideration of the following set of questions for a particular host, pathogen, host\–pathogen combination, or geographic region. 1. Are multiple biological interactions important? 2. Are there environmental thresholds for population responses? 3. Are there indirect effects of global change factors on disease development? 4. Are spatial components of epidemic processes affected by climate? 5. Are there feedback loops for management? 6. Are networks for intervention technologies slower than epidemic networks? 7. Are there effects of plant disease on multiple ecosystem services? 8. Are there feedback loops from plant disease to climate change? Evaluation of these questions will help in gauging system complexity, as illustrated for fusarium head blight and potato late blight. In practice, it may be necessary to expand models to include more components, identify those components that are the most important, and synthesize such models to include the optimal level of complexity for planning and research prioritization.

}, keywords = {LTER-KNZ, cereal head blight, disease risk, ecosystem services, fusarium graminearum, phytophthora infestans, potato late blight}, doi = {10.1111/j.1365-3059.2010.02409.x}, url = {https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-3059.2010.02409.x}, author = {Garrett, K.A. and Forbes, G.A. and Savary, S. and Skelsey, P. and Sparks, A.H. and Valdivia, C. and van Bruggen, A.H.C. and Willocquet, L. and Djurle, A. and Duveiller, E. and Eckersten, H. and Pande, S. and Vera Cruz, C. and Yuen, J.} } @article {KNZ001431, title = {Cross-stream comparison of substrate-specific denitrification potential}, journal = {Biogeochemistry}, volume = {104}, year = {2011}, pages = {381 -392}, abstract = {

Headwater streams have a demonstrated ability to denitrify a portion of their nitrate (NO3 \−) load but there has not been an extensive consideration of where in a stream this process is occurring and how various habitats contribute to total denitrification capability. As part of the Lotic Intersite Nitrogen Experiment II (LINX II) we measured denitrification potential in 65 streams spanning eight regions of the US and draining three land-use types. In each stream, potential denitrification rates were measured in common substrate types found across many streams as well as locations unique to particular streams. Overall, habitats from streams draining urban and agricultural land-uses showed higher potential rates of denitrification than reference streams draining native vegetation. This difference among streams was probably driven by higher ambient nitrate concentrations found in urban or agricultural streams. Within streams, sandy habitats and accumulations of fine benthic organic matter contributed more than half of the total denitrification capacity (mg N removed m\−2 h\−1). A particular rate of potential denitrification per unit area could be achieved either by high activity per unit organic matter or lower activities associated with larger standing stocks of organic matter. We found that both small patches with high rates (hot spots) or more widespread but less active areas (cool matrix) contributed significantly to whole stream denitrification capacity. Denitrification estimated from scaled-up denitrification enzyme assay (DEA) potentials were not always dramatically higher than in situ rates of denitrification measured as 15N gas generation following 24-h 15N\–NO3 tracer additions. In general, headwater streams draining varying land-use types have significant potential to remove nitrate via denitrification and some appear to be functioning near their maximal capacity.

}, keywords = {LTER-KNZ, Comparative, Comparison of potential with realized denitrification, DEA, denitrification, stream, Substrate-specific}, doi = {10.1007/s10533-010-9512-8}, url = {https://link.springer.com/article/10.1007\%2Fs10533-010-9512-8}, author = {Findlay, S.E.G. and Mulholland, P.J. and Hamilton, S. and Tank, J. and Bernot, M. and Burgin, A.J. and Crenshaw, C. and W. K. Dodds and Grimm, N. and W.H. McDowell and Potter, J. and Sobota, D.} } @article {KNZ001434, title = {Direct and indirect effects of central stoneroller (Campostoma anomalum) on mesocosm recovery following a flood: can macroconsumers affect denitrification?}, journal = {Journal of the North American Benthological Society}, volume = {30}, year = {2011}, pages = {840 -852}, abstract = {

Anthropogenic N loadings and perturbations of macroconsumer communities impair ecological and economic services provided by streams. Organisms are adapted to natural disturbances, such as flooding and desiccation, but how anthropogenic and natural disturbances interact is poorly understood. We used large outdoor mesocosms to study the effect of Campostoma anomalum, a common prairie headwater-stream minnow, and NH4+ additions (to simulate fish excretion) on the recovery of ecosystem structure and function following a flood, highlighting the potential for Campostoma (and other macroconsumers) to affect denitrification. Campostoma and NH4+ treatments differentially affected particulate organic matter size and filamentous algal structure. Ecosystem structure responded differently to mesocosm treatment over time, a result suggesting that grazers or NH4+-N availability may be especially important during early recovery periods. The presence of Campostoma did not influence denitrification, but NH4+ additions altered the response of denitrifiers to nutrient and energy amendments, and denitrification rates decreased following the recovery of mesocosms. Temporal changes in denitrification probably were caused by increasing hyporheic dissolved O2 concentrations, which led to potentially fewer anoxic microsites for production of denitrification enzymes. Our study shows that grazers affect the recovery of ecosystem structure, but denitrification in the context of these prairie-stream mesocosms appears to be unaffected by Campostoma.

}, keywords = {LTER-KNZ, Campostoma, denitrification, Ecosystem function, Flood, grazer, mesocosm, prairie streams, recovery}, doi = {10.1899/10-169.1}, url = {https://www.journals.uchicago.edu/doi/10.1899/10-169.1}, author = {Reisinger, A.J. and Presuma, D.L. and K. B. Gido and W. K. Dodds} } @article {KNZ001384, title = {The effect of environmental harshness on neurogenesis: a large-scale comparison}, journal = {Developmental Neurobiology}, volume = {71}, year = {2011}, pages = {246 -252}, abstract = {

Harsh environmental conditions may produce strong selection pressure on traits, such as memory, that may enhance fitness. Enhanced memory may be crucial for survival in animals that use memory to find food and, thus, particularly important in environments where food sources may be unpredictable. For example, animals that cache and later retrieve their food may exhibit enhanced spatial memory in harsh environments compared with those in mild environments. One way that selection may enhance memory is via the hippocampus, a brain region involved in spatial memory. In a previous study, we established a positive relationship between environmental severity and hippocampal morphology in food-caching black-capped chickadees (Poecile atricapillus). Here, we expanded upon this previous work to investigate the relationship between environmental harshness and neurogenesis, a process that may support hippocampal cytoarchitecture. We report a significant and positive relationship between the degree of environmental harshness across several populations over a large geographic area and (1) the total number of immature hippocampal neurons, (2) the number of immature neurons relative to the hippocampal volume, and (3) the number of immature neurons relative to the total number of hippocampal neurons. Our results suggest that hippocampal neurogenesis may play an important role in environments where increased reliance on memory for cache recovery is critical. \© 2010 Wiley Periodicals, Inc. Develop Neurobiol 71: 246\–252, 2011.

}, keywords = {LTER-KNZ, black-capped chickadee, food hoarding, hippocampus, latitudinal gradient, neuron, spatial memory}, doi = {10.1002/dneu.20847}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/dneu.20847}, author = {Chancellor, L.V. and Roth, T.C. and LaDage, L.D. and Pravosudov, V.V.} } @mastersthesis {KNZ001470, title = {A generalist grasshopper species (Melanoplus femurrubrum) is adapted to variable environments along a latitudinal gradient}, volume = {MS Thesis}, year = {2011}, school = {Kansas State University}, type = {M.S. Thesis}, address = {Manhattan, KS}, abstract = {

Temperature and food quality vary across broad latitudinal gradients, greatly affecting performance by insect herbivores. The contribution of each varies latitudinally so that geographically distinct populations are challenged by differences in nutritional needs and energetic demands. While there has been extensive work studying diet selectivity and nutritional ecology of insect herbivores, few studies have focused on how insect herbivores adapt across such vast environmental gradients. The generalist-feeding grasshopper, Melanoplus femurrubrum (DeGreer), has a broad geographic range that extends across much of North America, making this species ideal for comparative investigations of intrinsic performance responses to extensive but predictable patterns of environmental variation. I compared responses by six populations collected from populations located from Texas to North Dakota (USA) using a common garden experimental design to investigate clinal responses in grasshopper performance. I examined responses in: (1) body size, (2) thermoregulation and adaptive coloration, (3) developmental and growth rates, (4) metabolic rates, (5) total consumption and rates, (6) diet ratio selection, and (7) digestive processing efficiencies across the latitudinal gradient. Grasshopper body size followed the Converse Bergmann\’s Rule with decreasing body size as latitude increased. Temperature influenced all other responses, but responses to diet were not always significant or directional. Latitudinal trends for development and growth rates were observed but mass-specific metabolic rates were similar for all populations. Total consumption was body size dependent but independent of diet type. Mass-specific consumption varied but no single directional trend was detected. There was a shift in carbohydrate-biased diet preference at low latitude toward protein-biased diet ratios at higher latitudes, suggesting adaptations to different energetic demands by these populations. However, post-ingestive (digestive) efficiencies demonstrated variable responses with northern populations observing highest efficiencies for some indices but not all. Overall, this research documents phenotypic plasticity to environmental variability to some degree for digestive efficiencies, but ecotypic responses in body size and diet preference among M. femurrubrum populations were observed.

}, keywords = {LTER-KNZ, body size, latitudinal gradient, Melanoplus femurrubrum, nutritional ecology, Performance, Temperature}, url = {http://hdl.handle.net/2097/13093}, author = {Parsons, S.} } @article {KNZ001297, title = {Hierarchical modeling of lek habitats of Greater Prairie-Chickens}, journal = {Studies in Avian Biology}, volume = {39}, year = {2011}, pages = {21 -32}, keywords = {LTER-KNZ}, url = {https://www.fws.gov/southwest/es/documents/R2ES/LitCited/LPC_2012/Gregory_et_al_2011.pdf}, author = {Gregory, A.J. and McNew, L.B. and Prebyl, T.J. and Sandercock, B.K. and Wisely, S.M.} } @article {KNZ001437, title = {Land fragmentation under rapid urbanization: A cross-site analysis of Southwestern cities}, journal = {Urban Ecosystems}, volume = {14}, year = {2011}, pages = {429 -455}, abstract = {

Explosive population growth and increasing demand for rural homes and lifestyles fueled exurbanization and urbanization in the western USA over the past decades. Using National Land Cover Data we analyzed land fragmentation trends from 1992 to 2001 in five southwestern cities associated with Long Term Ecological Research (LTER) sites. We observed two general fragmentation trends: expansion of the urbanized area leading to fragmentation in the exurban and peri-urban regions and decreased fragmentation associated with infill in the previously developed urban areas. We identified three fragmentation patterns, riparian, polycentric, and monocentric, that reflect the recent western experience with growth and urbanization. From the literature and local expert opinion, we identified five relevant drivers \– water provisioning, population dynamics, transportation, topography, and institutions \– that shape land use decision-making and fragmentation in the southwest. In order to assess the relative importance of each driver on urbanization, we linked historical site-specific driver information obtained through literature reviews and archival analyses to the observed fragmentation patterns. Our work highlights the importance of understanding land use decision-making drivers in concert and throughout time, as historic decisions leave legacies on landscapes that continue to affect land form and function, a process often forgotten in a region and era of blinding change.

}, keywords = {LTER-KNZ, Exurbanization, Land fragmentation, The US Southwest, Urban ecology}, doi = {10.1007/s11252-011-0157-8}, url = {https://link.springer.com/article/10.1007\%2Fs11252-011-0157-8}, author = {York, A.M. and Shrestha, M. and Boone, C.G. and Zhang, S. and J. A. Harrington and Prebyl, T.J. and Swann, A. and Agar, M. and Antolin, M.F. and Nolen, B. and Wright, J.B. and Skaggs, R.} } @article {KNZ001416, title = {Late Quaternary environmental change inferred from phytoliths and other soil-related proxies: case studies from the central and southern Great Plains}, journal = {Catena}, volume = {85}, year = {2011}, pages = {87 -108}, abstract = {

This study investigates stable carbon isotopes (δ13C), opal phytolith assemblages, burnt phytoliths, microscopic charcoal and Sporormiella spores from modern soils and paleosols in Kansas and Oklahoma. Grass and dicot phytoliths in combination with δ13C are used as proxies for reconstructing the structure of grasslands and woodlands. Burnt grass phytoliths and microscopic charcoal are evaluated as proxies for reconstructing paleofire incidence. Concentrations of the fungal spore Sporormiella are used as a proxy for assessing large herbivore activity. These proxies were tested on various modern grassland communities of the central and southern Great Plains, including areas with bison, cattle, and small herbivores, and areas under different fire frequencies. Opal phytolith assemblages and δ13C values show that before cal 11 ka, C3 grasses and woody plants predominated in areas that today are dominated by C4 grasses. The origin of the shortgrass prairie dates back to about cal 10 ka. The origin of the tallgrass prairie, however, is not clear as phytolith data show variable assemblages throughout the Holocene (mixed-grass, tallgrass, and tallgrass\–woodland mosaic). Different proxies (burnt phytoliths vs. charcoal) reveal different fire frequencies, but it is apparent that microfossil evidence for fire incidence is closely related to the abundance of woody plants in the landscape. Before cal 12 ka, soils show somewhat elevated concentration of Sporormiella, but lower concentrations than the modern high-density bison and cattle grazing areas. Throughout the Holocene, Sporormiella frequencies are low, which suggests lower large ungulate densities and perhaps high mobility.

}, keywords = {LTER-KNZ, Charcoal, Great Plains, Opal phytoliths, Paleosols, Sporormiella, Stable carbon isotopes}, doi = {10.1016/j.catena.2010.08.015}, url = {https://www.sciencedirect.com/science/article/pii/S0341816210001359?via\%3Dihub}, author = {Cordova, C.E. and Johnson, W.C. and Mandel, R.D. and Palmer, M.W.} } @article {KNZ001360, title = {Nitrous oxide emission from denitrification in stream and river networks}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {108}, year = {2011}, pages = {214 -219}, abstract = {

Nitrous oxide (N2O) is a potent greenhouse gas that contributes to climate change and stratospheric ozone destruction. Anthropogenic nitrogen (N) loading to river networks is a potentially important source of N2O via microbial denitrification that converts N to N2O and dinitrogen (N2). The fraction of denitrified N that escapes as N2O rather than N2 (i.e., the N2O yield) is an important determinant of how much N2O is produced by river networks, but little is known about the N2O yield in flowing waters. Here, we present the results of whole-stream 15N-tracer additions conducted in 72 headwater streams draining multiple land-use types across the United States. We found that stream denitrification produces N2O at rates that increase with stream water nitrate (NO3\−) concentrations, but that \<1\% of denitrified N is converted to N2O. Unlike some previous studies, we found no relationship between the N2O yield and stream water NO3\−. We suggest that increased stream NO3\− loading stimulates denitrification and concomitant N2O production, but does not increase the N2O yield. In our study, most streams were sources of N2O to the atmosphere and the highest emission rates were observed in streams draining urban basins. Using a global river network model, we estimate that microbial N transformations (e.g., denitrification and nitrification) convert at least 0.68 Tg\·y\−1 of anthropogenic N inputs to N2O in river networks, equivalent to 10\% of the global anthropogenic N2O emission rate. This estimate of stream and river N2O emissions is three times greater than estimated by the Intergovernmental Panel on Climate Change. Humans have more than doubled the availability of fixed nitrogen (N) in the biosphere, particularly through the production of N fertilizers and the cultivation of N-fixing crops (1). Increasing N availability is producing unintended environmental consequences including enhanced emissions of nitrous oxide (N2O), a potent greenhouse gas (2) and an important cause of stratospheric ozone destruction (3). The Intergovernmental Panel on Climate Change (IPCC) estimates that the microbial conversion of agriculturally derived N to N2O in soils and aquatic ecosystems is the largest source of anthropogenic N2O to the atmosphere (2). The production of N2O in agricultural soils has been the focus of intense investigation (i.e., \>1,000 published studies) and is a relatively well constrained component of the N2O budget (4). However, emissions of anthropogenic N2O from streams, rivers, and estuaries have received much less attention and remain a major source of uncertainty in the global anthropogenic N2O budget. Microbial denitrification is a large source of N2O emissions in terrestrial and aquatic ecosystems. Most microbial denitrification is a form of anaerobic respiration in which nitrate (NO3\−, the dominant form of inorganic N) is converted to dinitrogen (N2) and N2O gases (5). The proportion of denitrified NO3\− that is converted to N2O rather than N2 (hereafter referred to as the N2O yield and expressed as the mole ratio) partially controls how much N2O is produced via denitrification (6), but few studies provide information on the N2O yield in streams and rivers because of the difficulty of measuring N2 and N2O production in these systems. Here we report rates of N2 and N2O production via denitrification measured using whole-stream 15NO3\−-tracer experiments in 72 headwater streams draining different land-use types across the United States. This project, known as the second Lotic Intersite Nitrogen eXperiment (LINX II), provides unique whole-system measurements of the N2O yield in streams. Although N2O emission rates have been reported for streams and rivers (7, 8), the N2O yield has been studied mostly in lentic freshwater and marine ecosystems, where it generally ranges between 0.1 and 1.0\%, although yields as high as 6\% have been observed (9). These N2O yields are low compared with observations in soils (0\–100\%) (10), which may be a result of the relatively lower oxygen (O2) availability in the sediments of lakes and estuaries. However, dissolved O2 in headwater streams is commonly near atmospheric equilibrium and benthic algal biofilms can produce O2 at the sediment\–water interface, resulting in strong redox gradients more akin to those in partially wetted soils. Thus, streams may have variable and often high N2O yields, similar to those in soils (11). The N2O yield in headwater streams is of particular interest because much of the NO3\− input to rivers is derived from groundwater upwelling into headwater streams. Furthermore, headwater streams compose the majority of stream length within a drainage network and have high ratios of bioreactive benthic surface area to water volume (12).

}, keywords = {LTER-KNZ}, doi = {10.1073/pnas.1011464108}, url = {https://www.pnas.org/content/108/1/214}, author = {Beaulieu, J.K. and Tank, J.L. and Hamilton, S.K. and Wollheim, W.M. and Hall, R.O. and Mulholland, P.J. and Peterson, B.J. and L.R. Ashkenas and Cooper, L.W. and Dahm, C.N. and W. K. Dodds and Grimm, N.B. and Johnson, S.L. and W.H. McDowell and Poole, G.C. and Valett, H.M. and Arango, C.P. and Bernot, M.J. and Burgin, A.J. and Crenshaw, C. and Helton, A.M. and Johnson, L. and O{\textquoteright}Brien, J.M. and Potter, J.D. and Sheibley, R.W. and Sobota, D.J. and Thomas, S.M.} } @article {KNZ001452, title = {Patterns of trait convergence and divergence among native and exotic species in herbaceous plant communities are not modified by nitrogen enrichment}, journal = {Journal of Ecology}, volume = {99}, year = {2011}, pages = {1327 -1338}, keywords = {LTER-KNZ}, doi = {10.1111/j.1365-2745.2011.01860.x}, url = {https://www.jstor.org/stable/41333056?seq=1$\#$page_scan_tab_contents}, author = {Cleland, E.E. and Clark, C.M. and Scott. L. Collins and Fargione, J.E. and Gough, L. and Gross, K.L. and Pennings, S.C. and K.N. Suding} } @article {KNZ001423, title = {Thinking outside the channel: modeling nitrogen cycling in networked river ecosystems}, journal = {Frontiers in Ecology and the Environment}, volume = {9}, year = {2011}, pages = {229 -238}, abstract = {

Agricultural and urban development alters nitrogen and other biogeochemical cycles in rivers worldwide. Because such biogeochemical processes cannot be measured empirically across whole river networks, simulation models are critical tools for understanding river-network biogeochemistry. However, limitations inherent in current models restrict our ability to simulate biogeochemical dynamics among diverse river networks. We illustrate these limitations using a river-network model to scale up in situ measures of nitrogen cycling in eight catchments spanning various geophysical and land-use conditions. Our model results provide evidence that catchment characteristics typically excluded from models may control river-network biogeochemistry. Based on our findings, we identify important components of a revised strategy for simulating biogeochemical dynamics in river networks, including approaches to modeling terrestrial\–aquatic linkages, hydrologic exchanges between the channel, floodplain/riparian complex, and subsurface waters, and interactions between coupled biogeochemical cycles.

}, keywords = {LTER-KNZ}, doi = {10.1890/080211}, url = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/080211}, author = {Helton, A.M. and Poole, G.C. and Meyer, J.L. and Wollheim, W.M. and Peterson, B.J. and Mulholland, P.J. and Bernhardt, E.S. and Stanford, J.A. and Arango, C.P. and L.R. Ashkenas and Cooper, L.W. and W. K. Dodds and Gregory, S.V. and O{\textquoteright}Hall, R. and Hamilton, S.K. and Johnson, S.L. and W.H. McDowell and Potter, J.D. and Tank, J.L. and Thomas, S.M. and Valett, H.M. and Webster, J.R. and Lydia H. Zeglin} } @article {KNZ001350, title = {Vegetation responses to an animal-generated disturbance (bison wallows) in tallgrass prairie}, journal = {American Midland Naturalist}, volume = {165}, year = {2011}, pages = {60 -73}, abstract = {

Bison (Bos bison) were a keystone species in the tallgrass prairie region of the Great Plains of North America. Cattle (Bos taurus) have been described as a functional equivalent to bison and have replaced bison in most of the grassland that remains intact. However, non-grazing behaviors influence grassland dynamics and are dissimilar between bison and cattle. Wallowing behavior (a non-grazing behavior by bison, but not cattle) creates disturbances (wallows) that were a common feature (may have numbered more than 100 million) of tallgrass prairie prior to extirpation of bison and conversion of most land to row-crop agriculture. We hypothesized that wallows are a unique disturbance that significantly influence both the structure and function of tallgrass prairie. We examined the response of plants to wallowing disturbances on Konza Prairie Biological Station, Kansas, where a herd of approximately 200 bison had year-round access to 1000 ha of native tallgrass prairie. We determined the influence of this disturbance type on aboveground net primary production (ANPP), plant species richness and diversity, and plant life form richness and diversity. The ANPP at the edge of wallowing disturbances was double the production in wallows and in adjacent prairie, which were not different from year to year. Plant species richness and diversity were significantly lower in wallows than at the edge of wallows and in adjacent prairie during all years of the study. However, composition of species were dissimilar among locations (e.g., 16\% of all plant species samples were found only in the wallows); and, therefore, wallows increased the local and likely regional diversity of plant species. Likewise, wallowing disturbances increased local richness and diversity of plant life forms. It appears that these once common wallowing disturbances increase the diversity of tallgrass prairie beyond that of prairie that is grazed only (i.e., prairie with cattle).

}, keywords = {LTER-KNZ}, doi = {10.1674/0003-0031-165.1.60}, url = {https://doi.org/10.1674/0003-0031-165.1.60}, author = {McMillan, B.R. and Pfeiffer, K.A. and D.W. Kaufman} } @mastersthesis {KNZ001398, title = {Climate forcings and the nonlinear dynamics of grassland ecosystems}, volume = {MS Thesis}, year = {2010}, school = {University of Kansas}, type = {M.S. Thesis}, address = {Lawrence, KS}, abstract = {

The nonlinear interaction of climate forcings and ecosystem variables is instrumental in creating the temporal and spatial heterogeneity of grasslands. Ecosystem processes are a product of these interactions and vary in sensitivity to them across time. How forcings aggregate and shape ecosystem responses is an important aspect of grassland states and defines how they respond to changes in environmental conditions. Characterizing the relationship between climate drivers and ecosystem variables helps sharpen analysis of ecosystem flux dynamics during the growing season and identifies likely deviations from mean functioning. To address the question of how climate forcings and ecosystem variables interact to shape seasonal water and carbon dynamics in grasslands, this thesis is split into two analysis chapters. The first (Chapter 3) is a characterization of water and carbon flux responses to variable precipitation timing and magnitude. Particular focus is placed on temporal sensitivity to inputs, seasonality in water flux dynamics, and the linkage between precipitation, soil moisture, evapotranspiration, and potential evaporation. Chapter 4 extends International Panel on Climate Change (IPCC A1B) regional climate scenario projections for the Central Plains of the United States to assess mesic grassland responses. The specific focus is assessing the ecosystem response to increased precipitation variability, increased potential evaporation, and earlier growing season onset. Effects of these forcings are shaped by simulations of constant and seasonally-varying water-use efficiency to assess the role of vegetation on grassland carbon assimilation, and also to explore species-specific responses at the Konza Prairie in North Central Kansas, USA. Results from both chapters show variation in seasonal sensitivity of fluxes to precipitation, with varying relationships between drivers, variable conditions, and fluxes. This research provides for a better understanding of ecosystem processes and provides assessment of the magnitude and extent that forcing variation has on grassland function. Results from the second chapter show increased seasonal water and carbon flux variability and increased frequency of water stress conditions. Vegetation responses suggest climate change will impact species and habitat compositions through changing environmental conditions and partitioning of carbon assimilation periods. This illustrates potential effects to grassland functioning and growing season dynamics.

}, keywords = {LTER-KNZ}, url = {http://hdl.handle.net/1808/6633}, author = {Petrie, M.} } @article {KNZ001347, title = {Inter-regional comparison of land-use effects on stream metabolism}, journal = {Freshwater Biology}, volume = {55}, year = {2010}, pages = {1874 -1890}, abstract = {1. Rates of whole-system metabolism (production and respiration) are fundamental indicators of ecosystem structure and function. Although first-order, proximal controls are well understood, assessments of the interactions between proximal controls and distal controls, such as land use and geographic region, are lacking. Thus, the influence of land use on stream metabolism across geographic regions is unknown. Further, there is limited understanding of how land use may alter variability in ecosystem metabolism across regions. 2. Stream metabolism was measured in nine streams in each of eight regions (n = 72) across the United States and Puerto Rico. In each region, three streams were selected from a range of three land uses: agriculturally influenced, urban-influenced, and reference streams. Stream metabolism was estimated from diel changes in dissolved oxygen concentrations in each stream reach with correction for reaeration and groundwater input. 3. Gross primary production (GPP) was highest in regions with little riparian vegetation (sagebrush steppe in Wyoming, desert shrub in Arizona/New Mexico) and lowest in forested regions (North Carolina, Oregon). In contrast, ecosystem respiration (ER) varied both within and among regions. Reference streams had significantly lower rates of GPP than urban or agriculturally influenced streams. 4. GPP was positively correlated with photosynthetically active radiation and autotrophic biomass. Multiple regression models compared using Akaike{\textquoteright}s information criterion (AIC) indicated GPP increased with water column ammonium and the fraction of the catchment in urban and reference land-use categories. Multiple regression models also identified velocity, temperature, nitrate, ammonium, dissolved organic carbon, GPP, coarse benthic organic matter, fine benthic organic matter and the fraction of all land-use categories in the catchment as regulators of ER. 5. Structural equation modelling indicated significant distal as well as proximal control pathways including a direct effect of land-use on GPP as well as SRP, DIN, and PAR effects on GPP; GPP effects on autotrophic biomass, organic matter, and ER; and organic matter effects on ER. 6. Overall, consideration of the data separated by land-use categories showed reduced inter-regional variability in rates of metabolism, indicating that the influence of agricultural and urban land use can obscure regional differences in stream metabolism.}, keywords = {LTER-KNZ}, doi = {10.1111/j.1365-2427.2010.02422.x}, author = {Bernot, M.J. and Sobota, D.J. and Hall, R.O. and Mulholland, P.J. and W. K. Dodds and Webster, J.R. and Tank, J.L. and L.R. Ashkenas and Cooper, L.W. and Dahm, C.N. and Gregory, S.V. and Grimm, N.B. and Hamilton, S.K. and Johnson, S.L. and W.H. McDowell and Meyer, J.L. and Peterson, B. and Poole, G.C. and Valett, H.M. and Arango, C.P. and Beaulieu, J.J. and Burgin, A.J. and Crenshaw, C. and Helton, A.M. and Johnson, L. and Merriam, J. and Niederlehner, B.R. and O{\textquoteright}Brien, J.M. and Potter, J.D. and Sheibley, R.W. and Thomas, S.M. and Wilson, K.} } @article {KNZ001313, title = {Learning capabilities enhanced in harsh environments: a common garden approach}, journal = {Proceedings of the Royal Society Biological Sciences}, volume = {277}, year = {2010}, pages = {3187 -3193}, abstract = {Previous studies have suggested that the ability to inhabit harsh environments may be linked to advanced learning traits. However, it is not clear if individuals express such traits as a consequence of experiencing challenging environments or if these traits are inherited. To assess the influence of differential selection pressures on variation in aspects of cognition, we used a common garden approach to examine the response to novelty and problem-solving abilities of two populations of black-capped chickadees (Poecile atricapillus). These populations originated from the latitudinal extremes of the species{\textquoteright}s range, where we had previously demonstrated significant differences in memory and brain morphology in a multi-population study. We found that birds from the harsh northern population, where selection for cognitive abilities is expected to be high, significantly outperformed conspecifics from the mild southern population. Our results imply differences in cognitive abilities that may be inherited, as individuals from both populations were raised in and had experienced identical environmental conditions from 10 days of age. Although our data suggest an effect independent of experience, we cannot rule out maternal effects or experiences within the nest prior to day 10 with our design. Nevertheless, our results support the idea that environmental severity may be an important factor in shaping certain aspects of cognition.}, keywords = {LTER-KNZ, behaviour, cognition, evolution}, doi = {10.1098/rspb.2010.0630}, author = {Roth, T.C. and LaDage, L.D. and Pravosudov, V.V.} } @article {KNZ001294, title = {Long-term community dynamics of small landbirds with and without exposure to extensive disturbance from military training activities}, journal = {Environmental Management}, volume = {45}, year = {2010}, pages = {203 -216}, abstract = {Military training activities are known to impact individual species, yet our understanding of how such activities influence animal communities is limited. In this study, we used long-term data in a case study approach to examine the extent to which the local small landbird community differed between a site in northeast Kansas that experienced intensive disturbance from military training activities (Ft. Riley Military Installation) and a similar, nearby site that experienced minimal human disturbance (Konza Prairie Biological Station). In addition, we characterized how the regional pool of potential colonizers influenced local community dynamics using Breeding Bird Survey data. From 1991 to 2001, most species of small terrestrial landbirds (73\%) recorded during breeding surveys were found at both sites and the mean annual richness at Ft. Riley (39.0 {\textpm} 2.86 [SD]) was very similar to that of Konza Prairie (39.4 {\textpm} 2.01). Richness was maintained at relatively constant levels despite compositional changes because colonizations compensated local extinctions at both sites. These dynamics were driven primarily by woodland species that exhibited stochastic losses and gains and were present at a low local and regional abundance. Our results suggest that military training activities may mimic natural disturbances for some species in this area because the small landbird community did not differ markedly between sites with and sites without extensive human disturbance. Although our results suggest that military training is not associated with large changes in the avian community, additional studies are needed to determine if this pattern is found in other ecological communities.}, keywords = {LTER-KNZ, Anthropogenic disturbance, Community dynamics, Grassland birds, Military training, Songbird conservation}, doi = {10.1007/s00267-009-9421-6}, author = {Rivers, J.W. and Gipson, P.S. and Althoff, D.P. and Pontius, J.S.} } @article {KNZ001253, title = {Mineralogy and morphological properties of buried polygenetic paleosols formed in late quaternary sediments on upland landscapes of the central plains, USA}, journal = {Geoderma}, volume = {154}, year = {2010}, pages = {508 -517}, abstract = {East central Kansas is largely comprised of alternating, level beds of Permian shale and limestone of the Central Plains, USA. Polygenetic upland soils of east central Kansas have been formed though multiple and likely different sets of soil forming factors. Upland soils in this region have a complex genesis, often contain one or more paleosols, and form in multiple parent materials including loess, locally reworked loess or colluvium, and residuum. The depth to bedrock rarely exceeds 2 m. Upland hillslope soils commonly contain one or more paleosols, and can be observed on a variety of hillslope positions on the landscape. Generally, the lower paleosols are recognized by strongly expressed structure, thick continuous clay coatings on all faces of peds, and strong reddish color with either 7.5YR or 5YR hues. Soil textures of the paleosols often feel less clayey than the overlying horizons in field determinations. At first, this was attributed to a decrease in clay content, stickiness, and plasticity. However, subsequent laboratory characterization revealed that the clay content was usually highest in the lower paleosol horizons, and that the clay mineralogy of the modern soil was dominated by smectite, while the paleosols contained a mixed suite of minerals. Therefore, the perceived decrease in clay content was caused by a change in clay mineralogy, a feature that can be exploited in future field descriptions in order to more accurately distinguish between stratigraphic units in these thin, welded polygenetic soils. The age of the paleosols sampled in this study were typical for the late Quaternary-aged Severance formation, clustering in two age ranges, which were ≈ 19,000 to 20,000 and ≈ 22,500 to 27,700 uncalibrated 14C yr BP. The results from this study illustrate that although they might be thin, truncated, and welded, late Quaternary-aged loess-derived soils and paleosols occur in regular, predictable patterns on many upland hillslopes in the Bluestem Hills Major Land Resource Area, and this region should be included in future regional investigations of the Central Plains.}, keywords = {LTER-KNZ, Central Plains, Great Plains, Landscapes, Loess, Mineralogy, Paleosols, Quaternary}, doi = {10.1016/j.geoderma.2009.03.015}, author = {Presley, D.R. and Hartley, P.E. and Ransom, M.D.} } @article {KNZ001271, title = {Road crossing designs and their impact on fish assemblages of Great Plains streams}, journal = {Transactions of the American Fisheries Society}, volume = {139}, year = {2010}, pages = {214 -222}, abstract = {

A mark\–recapture field study was conducted to determine fish passage at 5 concrete box culverts and 5 low-water crossings (concrete slabs vented by culverts) as well as 10 control sites (below a natural riffle) in Flint Hills streams of northeastern Kansas. Additionally, we tested the upstream passage of four fish species native to Great Plains streams (Topeka shiner Notropis topeka, green sunfish Lepomis cyanellus, red shiner Cyprinella lutrensis, and southern redbelly dace Phoxinus erythrogaster) through three simulated crossing designs (box culverts, round corrugated culverts, and natural rock riffles) at water velocities of 0.1 to 1.1 m/s in an experimental stream. The field study indicated that cyprinids were twice as likely to move upstream of box culverts than low-water crossings and 1.4 times as likely to move upstream of control reaches than any crossing type. The best models indicated that the proportion of cyprinids that moved upstream increased with decreased culvert slope and length, perching, and increased culvert width. Our controlled experiment indicated that fish can move through velocities up to 1.1 m/s in a 1.86-m simulated stream and that the proportion of fish that moved upstream did not differ among crossing designs for southern redbelly dace, green sunfish, or Topeka shiner; however, natural rock riffles had lower proportional movements (mean = 0.19) than the box (0.38) or corrugated culvert designs (0.43) for red shiners. Water velocity did not affect the proportional upstream movement of any species except that of Topeka shiners, which increased with water velocity. Crossing design alone may not determine fish passage, and water velocities up to 1.1 m/s may not affect the passage of many Great Plains fishes. Barriers to fish movement may be the result of other factors (e.g., perching, slope, and crossing length). The use of properly designed and installed crossings has promise in conserving Great Plains stream fishes.

}, keywords = {LTER-KNZ}, doi = {10.1577/T09-040.1}, url = {https://afspubs.onlinelibrary.wiley.com/doi/abs/10.1577/T09-040.1}, author = {Bouska, W.W. and Paukert, C.P.} } @article {KNZ001418, title = {Shifting fungal endophyte communities colonize Bouteloua gracilis: effect of host tissue and geographical distribution}, journal = {Mycologia}, volume = {102}, year = {2010}, pages = {1012 -1026}, abstract = {

Communities of root-associated fungi (RAF) commonly have been studied under the auspices of arbuscular mycorrhizal fungi (AMF) or ectomycorrhizal fungi. However many studies now indicate that other groups of endophytic RAF, including dark septate endophytes (DSE) are more abundant in some plants and environments. The common forage grass, Bouteloua gracilis, was used as a model to examine whether RAF also colonize different organs within the same plant and to compare RAF communities from sites across North America, spanning the latitudinal range of B. gracilis (from Canada to Mexico). We compared the RAF communities of organs within individual plants at one site and within plant roots among six sites. With the possible exception of one group related to genus Paraphaeosphaeria there was little evidence that RAF colonized vertically beyond the crowns. Furthermore, although there was some variation in the constitution of rare members of the RAF communities, several taxonomically related groups dominated the RAF community at all sites. These dominant taxa included members in the Pleosporales (related to the DSE, Paraphaeosphaeria spp.), Agaricales (related to Moniliophthora spp., or Campanella spp.) and Hypocreales (related to Fusarium spp.). AMF were notable by their near absence. Similar phylotypes from the dominant groups clustered around adjacent sites so that similarity of the RAF communities was negatively correlated to site inter-distance and the RAF communities appeared to group by country. These results increase the possibility that at least some of these common and widely distributed core members of the RAF community form important, intimate and long lasting relationships with grasses.

}, keywords = {LTER-KNZ, Bouteloua gracilis, dark septate endophytes, endophytic fungi, grassland fungi, Grasslands National Park, Janos, Konza Prairie, Llanos de Ojuelos, Sevilleta, Wind Cave National Park}, doi = {10.3852/09-264}, url = {https://www.tandfonline.com/doi/abs/10.3852/09-264?journalCode=umyc20}, author = {Herrera, J. and Khidir, H.H. and Eudy, D.M. and Porras-Alfaro, A. and Natvig, D.O. and Sinsabaugh, R.L.} } @inbook {KNZ001204, title = {Approaches to predicting broad-scale regime shifts using changing pattern-process relationships across scales}, booktitle = {Real World Ecology: Design and Analyses of Large-Scale and Long-Term Research}, year = {2009}, publisher = {Springer-Verlag, NY}, organization = {Springer-Verlag, NY}, abstract = {Understanding and predicting the occurrence of alternative ecosystem states (i.e., regime shifts) at broad scales is a pressing challenge for ecologists given the scope and nature of global change. In many cases, regime shifts at broad-scales are affected by pattern-process relationships across a range of finer scales. However, experimental and analytical methods to examine state changes, such as from perennial grasslands to woodlands, have not been fully developed. We first define and describe the expansion of woody plants into perennial grasslands. Woody plant encroachment has well-documented consequences for local, regional, and global ecology, and takes several forms, from shrub invasion in arid/semiarid grasslands and arctic ecosystems to tree invasion in mesic and alpine grasslands. We then outline a multi-scale experimental approach to examining the key processes influencing woody plant encroachment from fine to broad scales, and describe the application of this approach to the Jornada Basin Agricultural Research Service-Long Term Ecological Research site as a case study. Several questions can be addressed with this approach, such as: how and under what conditions do dynamics and decisions made at fine scales influence dynamics at broader scales? How and under what conditions do broad-scale dynamics overwhelm fine-scale processes to influence landscape patterns? Finally, we discuss analytical techniques for predicting regime shifts and their associated thresholds.}, keywords = {LTER-KNZ, broad-scale regime, pattern-process}, url = {http://www.springer.com/us/book/9780387779416}, author = {Peters, D.P.C. and B.T. Bestelmeyer and Alan K. Knapp and Herrick, J.E. and Monger, H.C. and Havstad, K.M.}, editor = {Miao, S. and Carstenn, S. and Nungesser, M.} } @article {KNZ001254, title = {Beyond yield: plant disease in the context of ecosystem services}, journal = {Phytopathology}, volume = {99}, year = {2009}, pages = {1228 -1236}, abstract = {

The ecosystem services concept provides a means to define successful disease management more broadly, beyond short-term crop yield evaluations. Plant disease can affect ecosystem services directly, such as through removal of plants providing services, or indirectly through the effects of disease management activities, including pesticide applications, tillage, and other methods of plant removal. Increased plant biodiversity may reduce disease risk if susceptible host tissue becomes less common, or may increase risk if additional plant species are important in completing pathogen life cycles. Arthropod and microbial biodiversity may play similar roles. Distant ecosystems may provide a disservice as the setting for the evolution of pathogens that later invade a focal ecosystem, where plants have not evolved defenses. Conversely, distant ecosystems may provide a service as sources of genetic resources of great value to agriculture, including disease resistance genes. Good policies are needed to support conservation and optimal use of genetic resources, protect ecosystems from exotic pathogens, and limit the homogeneity of agricultural systems. Research is needed to provide policy makers, farmers, and consumers with the information required for evaluating trade-offs in the pursuit of the full range of ecosystem services desired from managed and native ecosystems.

}, keywords = {LTER-KNZ, biological control}, doi = {10.1094/PHYTO-99-11-1228}, url = {https://apsjournals.apsnet.org/doi/10.1094/PHYTO-99-11-1228}, author = {Cheatham, M.R. and Rouse, M.N. and Esker, P.D. and Ignacio, S. and Pradel, W. and Raymundo, R. and Sparks, A.H. and Forbes, G.A. and Gordon, T.R. and Garrett, K.A.} } @article {KNZ001228, title = {Hippocampal volumes and neuron numbers increase along a gradient of environmental harshness: a large-scale comparison}, journal = {Proceedings of the Royal Society B}, volume = {276}, year = {2009}, pages = {401 -405}, abstract = {

Environmental conditions may provide specific demands for memory, which in turn may affect specific brain regions responsible for memory function. For food-caching animals, in particular, spatial memory appears to be important because it may have a direct effect on fitness via the accuracy of cache retrieval. Animals living in more harsh environments should rely more on cached food, and thus theoretically should have better memory to support cache retrieval, which may be crucial for survival. Consequently, animals in harsh environments may benefit from more neurons within a larger hippocampus (Hp), a part of the brain involved in spatial memory. Here, we present the first large-scale test of the hypothesis that Hp structure is related to the severity of the environment within a single food-caching species (the black-capped chickadee, Poecile atricapillus) with a large range encompassing a great diversity of climatic conditions. Hp size in birds collected at five locations along a gradient of environmental harshness from Alaska to Kansas ranked perfectly with climatic severity. Birds from more harsh northern climates (defined by lower ambient temperature, shorter day length and more snow cover) had significantly larger Hp volumes and more Hp neurons (both relative to telencephalon volume) than those from more mild southern latitudes. Environmental pressures therefore seem capable of influencing specific brain regions independently, which may result in enhanced memory, and hence survival, in harsh climates.

}, keywords = {LTER-KNZ}, doi = {10.1098/rspb.2008.1184}, url = {https://royalsocietypublishing.org/doi/10.1098/rspb.2008.1184}, author = {Roth, T.C. and Pravosudov, V.V.} } @article {KNZ001249, title = {Long-term patterns of mass loss during the decomposition of leaf and fine root litter: an intersite comparison}, journal = {Global Change Biology}, volume = {15}, year = {2009}, pages = {1320 -1338}, abstract = {

Decomposition is a critical process in global carbon cycling. During decomposition, leaf and fine root litter may undergo a later, relatively slow phase; past long-term experiments indicate this phase occurs, but whether it is a general phenomenon has not been examined. Data from Long-term Intersite Decomposition Experiment Team, representing 27 sites and nine litter types (for a total of 234 cases) was used to test the frequency of this later, slow phase of decomposition. Litter mass remaining after up to 10 years of decomposition was fit to models that included (dual exponential and asymptotic) or excluded (single exponential) a slow phase. The resultant regression equations were evaluated for goodness of fit as well as biological realism. Regression analysis indicated that while the dual exponential and asymptotic models statistically and biologically fit more of the litter type\–site combinations than the single exponential model, the latter was biologically reasonable for 27\–65\% of the cases depending on the test used. This implies that a slow phase is common, but not universal. Moreover, estimates of the decomposition rate of the slowly decomposing component averaged 0.139\–0.221 year\−1 (depending on method), higher than generally observed for mineral soil organic matter, but one-third of the faster phase of litter decomposition. Thus, this material may be slower than the earlier phases of litter decomposition, but not as slow as mineral soil organic matter. Comparison of the long-term integrated decomposition rate (which included all phases of decomposition) to that for the first year of decomposition indicated the former was on average 75\% that of the latter, consistent with the presence of a slow phase of decomposition. These results indicate that the global store of litter estimated using short-term decomposition rates would be underestimated by at least one-third.

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1365-2486.2008.01837.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2486.2008.01837.x}, author = {Harmon, M.E. and Silver, W.L. and Fasth, B. and Chen, H. and Burke, I.C. and Parton, W.J. and Hart, S.C. and Currie, W.S.} } @article {KNZ001290, title = {Mysterious mycorrhizae? A field trip and classroom experiment to demystify the symbioses formed between plants and fungi}, journal = {American Biology Teacher}, volume = {71}, year = {2009}, pages = {424 -429}, keywords = {LTER-KNZ}, url = {https://ecommons.luc.edu/cgi/viewcontent.cgi?article=1002\&context=ies_facpubs}, author = {Johnson, N.C. and Chaudhary, V.B. and Hoeksema, J.D. and Moore, J.M. and Pringle, A. and Umbanhowar, J.A. and G.T. Wilson} } @article {KNZ001251, title = {Nitrate removal in stream ecosystems measured by 15N addition experiments: Denitrification}, journal = {Limnology and Oceanography}, volume = {54}, year = {2009}, pages = {666 -680}, abstract = {

We measured denitrification rates using a field 15NO3\− tracer-addition approach in a large, cross-site study of nitrate uptake in reference, agricultural, and suburban-urban streams. We measured denitrification rates in 49 of 72 streams studied. Uptake length due to denitrification (SWdenn) ranged from 89 m to 184 km (median of 9050 m) and there were no significant differences among regions or land-use categories, likely because of the wide range of conditions within each region and land use. N2 production rates far exceeded N2O production rates in all streams. The fraction of total NO3\− removal from water due to denitrification ranged from 0.5\% to 100\% among streams (median of 16\%), and was related to NH4+ concentration and ecosystem respiration rate (ER). Multivariate approaches showed that the most important factors controlling SWden were specific discharge (discharge / width) and NO3\− concentration (positive effects), and ER and transient storage zones (negative effects). The relationship between areal denitrification rate (Uden) and NO3\− concentration indicated a partial saturation effect. A power function with an exponent of 0.5 described this relationship better than a Michaelis-Menten equation. Although Uden increased with increasing NO3\− concentration, the efficiency of NO3\− removal from water via denitrification declined, resulting in a smaller proportion of streamwater NO3\− load removed over a given length of stream. Regional differences in stream denitrification rates were small relative to the proximate factors of NO3\− concentration and ecosystem respiration rate, and land use was an important but indirect control on denitrification in streams, primarily via its effect on NO3\− concentration.

}, keywords = {LTER-KNZ}, doi = {10.4319/lo.2009.54.3.0666}, url = {https://aslopubs.onlinelibrary.wiley.com/doi/abs/10.4319/lo.2009.54.3.0666}, author = {Mulholland, P.J. and Hall, R.O. and Sobota, D.J. and W. K. Dodds and Findlay, S.E.G. and Grimm, N.B. and Hamilton, S.K. and W.H. McDowell and O{\textquoteright}Brien, J.M. and Tank, J.L. and L.R. Ashkenas and Cooper, L.W. and Dahm, C.N. and Gregory, S.V. and Johnson, S.L. and Meyer, J.L. and Peterson, B.J. and Poole, G.C. and Valett, H.M. and Webster, J.R. and Arango, C.P. and Beaulieu, J.J. and Bernot, M.J. and Burgin, A.J. and Crenshaw, C.L. and Helton, A.M. and Johnson, L.T. and Niederlehner, B.R. and Potter, J.D. and Sheibley, R.W. and Thomas, S.M.} } @article {KNZ001250, title = {Nitrate removal in stream ecosystems measured by 15N addition experiments: Total uptake}, journal = {Limnology and Oceanography}, volume = {54}, year = {2009}, pages = {653 -665}, abstract = {

We measured uptake length of 15NO3\− in 72 streams in eight regions across the United States and Puerto Rico to develop quantitative predictive models on controls of NO3\− uptake length. As part of the Lotic Intersite Nitrogen eXperiment II project, we chose nine streams in each region corresponding to natural (reference), suburban-urban, and agricultural land uses. Study streams spanned a range of human land use to maximize variation in NO3\− concentration, geomorphology, and metabolism. We tested a causal model predicting controls on NO3\− uptake length using structural equation modeling. The model included concomitant measurements of ecosystem metabolism, hydraulic parameters, and nitrogen concentration. We compared this structural equation model to multiple regression models which included additional biotic, catchment, and riparian variables. The structural equation model explained 79\% of the variation in log uptake length (SWtot). Uptake length increased with specific discharge (Q/w) and increasing NO3\− concentrations, showing a loss in removal efficiency in streams with high NO3\− concentration. Uptake lengths shortened with increasing gross primary production, suggesting autotrophic assimilation dominated NO3\− removal. The fraction of catchment area as agriculture and suburban-urban land use weakly predicted NO3\− uptake in bivariate regression, and did improve prediction in a set of multiple regression models. Adding land use to the structural equation model showed that land use indirectly affected NO3\− uptake lengths via directly increasing both gross primary production and NO3\− concentration. Gross primary production shortened SWtot, while increasing NO3\− lengthened SWtot resulting in no net effect of land use on NO3\− removal.

}, keywords = {LTER-KNZ}, doi = {10.4319/lo.2009.54.3.0653}, url = {https://aslopubs.onlinelibrary.wiley.com/doi/abs/10.4319/lo.2009.54.3.0653}, author = {Hall, R.O. Jr. and Tank, J.L. and Sobota, D.J. and Mulholland, P.J. and O{\textquoteright}Brien, J.M. and W. K. Dodds and Webster, J.R. and Valett, H.M. and Poole, G.C. and Peterson, B.J. and Meyer, J.L. and W.H. McDowell and Johnson, S.L. and Hamilton, S.K. and Grimm, N.B. and Gregory, S.V. and Dahm, C.N. and Cooper, L.W. and L.R. Ashkenas and Thomas, S.M. and Sheibley, R.W. and Potter, J.D. and Niederlehner, B.R. and Johnson, L.T. and Helton, A.M. and Crenshaw, C.M. and Burgin, A.J. and Bernot, M.J. and Beaulieu, J.J. and Arango, C.P.} } @article {KNZ001385, title = {Tough times call for bigger brains}, journal = {Communicative and Integrative Biology}, volume = {2}, year = {2009}, pages = {1 -3}, abstract = {

Memory is crucial for survival in many animals. Spatial memory in particular is important for food-caching species and may be influenced by selective pressures such as climate. The influence of climate on memory may be facilitated through the hippocampus (Hp), the part of the brain responsible in part for spatial memory. In a recent paper, we conducted the first large-scale test of the relationship between memory, the climate, and the brain in a single food-caching species, the black-capped chickadee (Poecile atricapillus). We found that birds from more harsh northern climates had significantly larger hippocampal volumes and more neurons than those from more mild southern latitudes. This work suggests that environmental pressures are capable of influencing specific brain regions, which may result in enhanced memory, and hence survival, in harsh climates. This work gives us a better understanding of how the brain responds to different environments and how animals can adapt to their environment in general.

}, keywords = {LTER-KNZ}, doi = {10.4161/cib.2.3.8099}, url = {https://www.tandfonline.com/doi/abs/10.4161/cib.2.3.8099}, author = {Roth, T.C. and Pravosudov, V.V.} } @article {KNZ001227, title = {Antibiotic resistance of Enterococci in American bison (Bison bison) from a nature preserve compared to that of Enterococci in pastured cattle}, journal = {Applied and Environmental Microbiology}, volume = {74}, year = {2008}, pages = {1726 -1730}, abstract = {

Enterococci isolated from a bison population on a native tall-grass prairie preserve in Kansas were characterized and compared to enterococci isolated from pastured cattle. The species diversity was dominated by Enterococcus casseliflavus in bison (62.4\%), while Enterococcus hirae was the most common isolate from cattle (39.7\%). Enterococcus faecalis was the second most common species isolated from bison (16\%). In cattle, E. faecalis and Enterococcus faecium were isolated at lower percentages (3.2\% and 1.6\%, respectively). No resistance to ampicillin, chloramphenicol, gentamicin, or high levels of vancomycin was detected from either source. Tetracycline and erythromycin resistance phenotypes, encoded by tetO and ermB, respectively, were common in cattle isolates (42.9\% and 12.7\%, respectively). A significant percentage of bison isolates (8\% and 4\%, respectively) were also resistant to these two antibiotics. The tetracycline resistance genes from both bison and cattle isolates resided on mobile genetic elements and showed a transfer frequency of 10\−6 per donor, whereas erythromycin resistance was not transferable. Resistance to ciprofloxacin was found to be higher in enterococci from bison (14.4\%) than in enterococci isolated from cattle (9.5\%). The bison population can serve as a sentinel population for studying the spread and origin of antibiotic resistance.

}, keywords = {LTER-KNZ}, doi = {10.1128/AEM.02164-07}, url = {https://aem.asm.org/content/74/6/1726}, author = {Anderson, J. F. and Parrish, T.D. and Akhtar, M. and Zurek, L. and Hirt, H.} } @article {KNZ001229, title = {Geographic patterns of song similarity in the Dickcissel (Spiza americana)}, journal = {Auk}, volume = {125}, year = {2008}, pages = {953 -964}, abstract = {

Song sharing among neighboring males is a well-known, frequent outcome of song learning in oscine passerines and some other groups, but only limited investigations of the spatial scale of this phenomenon have been pursued. On the basis of recordings of 1,043 individuals, we investigated song sharing in Dickcissels (Spiza americana) at local and regional scales at sites from northern Kansas to northern Oklahoma. Classification of song elements revealed decreasing song similarity with increasing distances between individual birds at small to intermediate scales, to ~10 km. At the largest spatial scales (10\–300 km between sites), there was very little similarity among sites and no obvious tendency for a decrease in similarity with increasing distances among our 30 sites. At our intensively sampled site, analyses of quantitative measurements showed that, at least for our most widely shared song element, frequency and duration were more similar in closer birds. Thus, distance between birds influences both quantitative and qualitative song similarity in Dickcissels. Variability existed among sites in the shape of the song-sharing decay curve, which indicates that other factors besides distance also govern song-sharing patterns. We found high repeatability of individual songs for both second-year (SY) and after-second-year (ASY) males throughout the season, and high conformity to the local song neighborhood in both SY and ASY males from their first recording soon after arrival in May. Returning ASY males sang the same song they had produced the previous breeding season.

}, keywords = {LTER-KNZ, culture, dialect, Dickcissel, Passeriformes, song sharing, spatial scale, Spiza americana}, doi = {10.1525/auk.2008.07164}, url = {https://academic.oup.com/auk/article/125/4/953/5148170}, author = {Schook, D.M. and Collins, M.D. and Jensen, W.E. and Williams, P.J. and Bader, N.E. and Parker, T.H.} } @article {KNZ001219, title = {Integrating soil ecological knowledge into restoration management}, journal = {Restoration Ecology}, volume = {16}, year = {2008}, pages = {608 -617}, abstract = {

The variability in the type of ecosystem degradation and the specificity of restoration goals can challenge restorationists\’ ability to generalize about approaches that lead to restoration success. The discipline of soil ecology, which emphasizes both soil organisms and ecosystem processes, has generated a body of knowledge that can be generally useful in improving the outcomes of restoration despite this variability. Here, we propose that the usefulness of this soil ecological knowledge (SEK) for restoration is best considered in the context of the severity of the original perturbation, the goals of the project, and the resilience of the ecosystem to disturbance. A straightforward manipulation of single physical, chemical, or biological components of the soil system can be useful in the restoration of a site, especially when the restoration goal is loosely defined in terms of the species and processes that management seeks to achieve. These single-factor manipulations may in fact produce cascading effects on several ecosystem attributes and can result in unintended recovery trajectories. When complex outcomes are desired, intentional and holistic integration of all aspects of the soil knowledge is necessary. We provide a short roster of examples to illustrate that SEK benefits management and restoration of ecosystems and suggest areas for future research.

}, keywords = {LTER-KNZ, ecosystem processes, feedbacks, Soil ecology}, doi = {10.1111/j.1526-100X.2008.00477.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1526-100X.2008.00477.x}, author = {Heneghan, L. and Miller, S. and S.G. Baer and Callaham, M.A. and Montgomery, J. and Rhoades, C.C. and Richardson, S. and Pauvo-Zuckerman, M.} } @article {KNZ001193, title = {Lakes and streams as sentinels of environmental change in terrestrial and atmospheric processes}, journal = {Frontiers in Ecology and the Environment}, volume = {6}, year = {2008}, pages = {247 -254}, abstract = {

Recent advances in our understanding of the importance of continental- to global-scale connectivity among terrestrial and aquatic ecosystems make consideration of aquatic\–terrestrial linkages an urgent ecological and environmental issue. Here, we describe the role of inland waters as sentinels and integrators of the impact of humans on terrestrial and aquatic ecosystems. The metabolic responses of lakes and streams (ie the rates at which these systems process carbon) are proposed as a common metric to integrate the impacts of environmental change across a broad range of landscapes. Lakes and streams transport and alter nutrients, contaminants, and energy, and store signals of environmental change from local to continental scales over periods ranging from weeks to millennia. A carefully conceived and well-integrated network that includes monitoring and experimental approaches to terrestrial\–aquatic connectivity is critical to an understanding of basic ecosystem-level processes and to forecasting and mitigating future environmental impacts at the continental scale.

}, keywords = {LTER-KNZ}, doi = {10.1890/070140}, url = {https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/070140}, author = {Williamson, C.E. and W. K. Dodds and Kratz, T.K. and Palmer, M.} } @article {KNZ001184, title = {Modeled interactive effects of precipitation, temperature, and CO2 on ecosystem carbon and water dynamics in different climatic zones}, journal = {Global Change Biology}, volume = {14}, year = {2008}, pages = {1986 -1999}, abstract = {

Interactive effects of multiple global change factors on ecosystem processes are complex. It is relatively expensive to explore those interactions in manipulative experiments. We conducted a modeling analysis to identify potentially important interactions and to stimulate hypothesis formulation for experimental research. Four models were used to quantify interactive effects of climate warming (T), altered precipitation amounts [doubled (DP) and halved (HP)] and seasonality (SP, moving precipitation in July and August to January and February to create summer drought), and elevated [CO2] (C) on net primary production (NPP), heterotrophic respiration (Rh), net ecosystem production (NEP), transpiration, and runoff. We examined those responses in seven ecosystems, including forests, grasslands, and heathlands in different climate zones. The modeling analysis showed that none of the three-way interactions among T, C, and altered precipitation was substantial for either carbon or water processes, nor consistent among the seven ecosystems. However, two-way interactive effects on NPP, Rh, and NEP were generally positive (i.e. amplification of one factor\&$\#$39;s effect by the other factor) between T and C or between T and DP. A negative interaction (i.e. depression of one factor\&$\#$39;s effect by the other factor) occurred for simulated NPP between T and HP. The interactive effects on runoff were positive between T and HP. Four pairs of two-way interactive effects on plant transpiration were positive and two pairs negative. In addition, wet sites generally had smaller relative changes in NPP, Rh, runoff, and transpiration but larger absolute changes in NEP than dry sites in response to the treatments. The modeling results suggest new hypotheses to be tested in multifactor global change experiments. Likewise, more experimental evidence is needed for the further improvement of ecosystem models in order to adequately simulate complex interactive processes.

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1365-2486.2008.01629.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2486.2008.01629.x}, author = {Luo, Y. and Gerten, D. and Le Maire, G. and Parton, W.J. and Weng, E. and Zhou, X. and Keough, C. and Beier, C. and Ciais, P. and Cramer, W. and Dukes, J.S. and Emmett, B. and Hanson, P.J. and Alan K. Knapp and Linder, S. and Nepstad, D. and Rustad, L.} } @article {KNZ001183, title = {Modelled effects of precipitation on ecosystem carbon and water dynamics in different climatic zones}, journal = {Global Change Biology}, volume = {14}, year = {2008}, pages = {1 -15}, abstract = {

The ongoing changes in the global climate expose the world\&$\#$39;s ecosystems not only to increasing CO2 concentrations and temperatures but also to altered precipitation (P) regimes. Using four well-established process-based ecosystem models (LPJ, DayCent, ORCHIDEE, TECO), we explored effects of potential P changes on water limitation and net primary production (NPP) in seven terrestrial ecosystems with distinctive vegetation types in different hydroclimatic zones. We found that NPP responses to P changes differed not only among sites but also within a year at a given site. The magnitudes of NPP change were basically determined by the degree of ecosystem water limitation, which was quantified here using the ratio between atmospheric transpirational demand and soil water supply. Humid sites and/or periods were least responsive to any change in P as compared with moderately humid or dry sites/periods. We also found that NPP responded more strongly to doubling or halving of P amount and a seasonal shift in P occurrence than that to altered P frequency and intensity at constant annual amounts. The findings were highly robust across the four models especially in terms of the direction of changes and largely consistent with earlier P manipulation experiments and modelling results. Overall, this study underscores the widespread importance of P as a driver of change in ecosystems, although the ultimate response of a particular site will depend on the detailed nature and seasonal timing of P change.

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1365-2486.2008.01651.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2486.2008.01651.x}, author = {Gerten, D. and Luo, Y. and Le Maire, G. and Parton, W.J. and Keough, C. and Weng, E. and Beier, C. and Ciais, P. and Cramer, W. and Dukes, J.S. and Emmett, B. and Hanson, P.J. and Alan K. Knapp and Linder, S. and Nepstad, D. and Rustad, L. and Sowerby, A.} } @article {KNZ001159, title = {Plasma cholinesterases for monitoring pesticide exposure in Nearctic-Neotropical migratory shorebirds}, journal = {Ornitholog{\'\i}a Neotropical}, volume = {19 (Suppl)}, year = {2008}, pages = {641 -651}, abstract = {Organophosphorus (OP) and carbamate (CB) pesticides are commonly used agrochemicals throughout the Western Hemisphere. These pesticides have caused mortalities in migratory birds and adverse physiological effects in trials with captive birds. Migratory shorebirds use a variety, of habitats during the austral summer in temperate South America and during migration through the Great Plains of the United States. Habitats where risk of exposure is high include rice fields and turf grass farms where agrochemicals are used. Cholinesterase (ChE) is a specific biomarker for monitoring OP and CB exposure and can be measured using standard laboratory procedures. Plasma ChE activity is useful as a non-lethal means of monitoring avian exposure to OP and CB pesticides. Many variables can affect enzyme activity and reactivation assays are not always possible, thus reference ChE values are a necessary component of monitoring exposure. During northbound migration in 2006, we sampled four upland and five wetland shore-bird species at four pesticide-free sites in North America, characterizing and measuring plasma ChEs in all shorebird species. Small-bodied species had higher levels of ChE activity in plasma than large-bodied species. Acetylcholinesterase (AChE), the enzyme whose inhibition leads to poisoning symptoms, showed less inter-specific variation than butyrylcholinesterase (BChE). Plasma ChE activities varied with date of capture in three of five species. Sex differences were significant in one of two species tested. Our baseline ChE values for migratory shorebirds provide a framework for future ecotoxicological studies of Nearctic-Neotropical migrant shorebirds.}, keywords = {LTER-KNZ}, url = {https://www.researchgate.net/publication/254414753_Plasma_cholinesterases_for_monitoring_pesticide_exposure_in_Nearctic-Neotropical_migratory_shorebirds}, author = {Strum, K.M. and Alfaro, M. and Haase, B. and Hooper, M.J. and Johnson, K.A. and Lanctot, R.B. and Lesterhuis, A.J. and L{\'o}pez, L. and Matz, A.C. and Morales, C. and Paulson, B. and Sandercock, B.K. and Torres-Dowdall, J. and Zaccagnini, M.E.} } @article {KNZ001191, title = {Predicting and understanding ecosystem responses to climate change at continental scales}, journal = {Frontiers in Ecology and the Environment}, volume = {6}, year = {2008}, pages = {273 -280}, abstract = {

Climate is changing across a range of scales, from local to global, but ecological consequences remain difficult to understand and predict. Such projections are complicated by change in the connectivity of resources, particularly water, nutrients, and propagules, that influences the way ecological responses scale from local to regional and from regional to continental. This paper describes ecological responses to expected changes in four key meso-scale drivers that influence the ecosystems of the North American continental interior: drought, warming, snowpack disappearance, and altered fire regimes. Changes in these drivers will affect, for example, atmospheric smoke, dust, and reactive nitrogen concentrations; stream discharge; nitrate concentrations; sediment loads; and the vector-borne spread of invasive species and infectious diseases. A continental network of sensors and simulation models is required to detect changes in the transport vectors \– atmospheric, hydrologic, and mechanized \–that connect spatial scales. Knowledge of these downwind, downstream, and down-corridor effects will be critical if we are to understand and forecast responses to climate change at regional to continental scales.

}, keywords = {LTER-KNZ}, doi = {10.1890/070165}, url = {https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/070165}, author = {Marshall, J.D. and John M. Blair and Peters, D.P.C. and Okin, G. and Rango, A. and Williams, M.} } @article {KNZ001181, title = {Rank clocks and plant community dynamics}, journal = {Ecology}, volume = {89}, year = {2008}, pages = {3534 -3541}, abstract = {Summarizing complex temporal dynamics in communities is difficult to achieve in a way that yields an intuitive picture of change. Rank clocks and rank abundance statistics provide a graphical and analytical framework for displaying and quantifying community dynamics. We used rank clocks, in which the rank order abundance for each species is plotted over time in temporal clockwise direction, to display temporal changes in species abundances and richness. We used mean rank shift and proportional species persistence to quantify changes in community structure in long-term data sets from fertilized and control plots in a late successional old field, frequently and infrequently burned tallgrass prairie, and Chihuahuan desert grassland and shrubland communities. Rank clocks showed that relatively constant species richness masks considerable temporal dynamics in relative species abundances. In the old field, fertilized plots initially experienced high mean rank shifts that stabilized rapidly below that of unfertilized plots. Rank shifts were higher in infrequently burned vs. annually burned tallgrass prairie and in desert grassland compared to shrubland vegetation. Proportional persistence showed that arid grasslands were more dynamic than mesic grasslands. We conclude that rank clocks and rank abundance statistics provide important insights into community dynamics that are often hidden by traditional univariate approaches.}, keywords = {LTER-KNZ}, doi = {10.1890/07-1646.1}, author = {Scott. L. Collins and K.N. Suding and Cleland, E.E. and Batty, M. and Pennings, S.C. and Gross, K.L. and Grace, J.S. and Gough, L. and Fargione, J.E. and Clark, C.M.} } @article {KNZ001196, title = {Responses of breeding birds in tallgrass prairie to fire and cattle grazing}, journal = {Journal of Field Ornithology}, volume = {79}, year = {2008}, pages = {41 -52}, abstract = {No other group of North American birds has declined as precipitously and over so large an area as has the grassland assemblage. In the Flint Hills of Kansas, the largest extant region of tallgrass prairie, annual spring burning of rangeland has largely replaced traditional regimes and natural patterns with longer intervals between burns. I examined effects of burning and low-intensity cattle grazing on abundances of seven bird species at Konza Prairie Research Natural Area in June 2002 and 2003. Every species was affected by fire, with Upland Sandpipers (Bartramia longicauda) more abundant, and six species{\textemdash}Grasshopper Sparrow (Ammodramus savannarum), Henslow{\textquoteright}s Sparrow (A. henslowii), Dickcissel (Spiza americana), Eastern Meadowlark (Sturnella magna), Brown-headed Cowbird (Molothrus ater), and Bell{\textquoteright}s Vireo (Vireo bellii){\textemdash}either less abundant or absent at sites in the breeding season following a fire. These results demonstrate that annual burning limits the potential of much of the Flint Hills prairie to harbor high breeding densities of many grassland birds. On the other hand, I found a trade-off between immediate and longer-term effects of burning for several grass-dependent species. Grasshopper Sparrows, Henslow{\textquoteright}s Sparrows, and Eastern Meadowlarks, although more numerous in areas that were not burned the preceding spring, were less abundant at sites burned every 4 yrs than those burned at shorter intervals. In contrast, shrub-dependent Bell{\textquoteright}s Vireos were more abundant at sites burned every 4 yrs. Upland Sandpipers, Grasshopper Sparrows, and Eastern Meadowlarks were more abundant in grazed areas. Use of alternatives to annual burning could increase habitat heterogeneity by transforming the Flint Hills into a mosaic of regularly, but asynchronously, burned pastures that would better meet the diverse habitat needs of the region{\textquoteright}s grassland birds.}, keywords = {LTER-KNZ}, doi = {10.1111/j.1557-9263.2008.00144.x}, author = {Powell, A.F.L.A.} } @article {KNZ001226, title = {Scale-dependent responses of plant biodiversity to nitrogen enrichment}, journal = {Ecology}, volume = {89}, year = {2008}, pages = {2165 -2171}, abstract = {Experimental studies demonstrating that nitrogen (N) enrichment reduces plant diversity within individual plots have led to the conclusion that anthropogenic N enrichment is a threat to global biodiversity. These conclusions overlook the influence of spatial scale, however, as N enrichment may alter β diversity (i.e., how similar plots are in their species composition), which would likely alter the degree to which N-induced changes in diversity within localities translate to changes in diversity at larger scales that are relevant to policy and management. Currently, it is unclear how N enrichment affects biodiversity at scales larger than a small plot. We synthesized data from 18 N-enrichment experiments across North America to examine the effects of N enrichment on plant species diversity at three spatial scales: small (within plots), intermediate (among plots), and large (within and among plots). We found that N enrichment reduced plant diversity within plots by an average of 25\% (ranging from a reduction of 61\% to an increase of 5\%) and frequently enhanced β diversity. The extent to which N enrichment altered β diversity, however, varied substantially among sites (from a 22\% increase to an 18\% reduction) and was contingent on site productivity. Specifically, N enrichment enhanced β diversity at low-productivity sites but reduced β diversity at high-productivity sites. N-induced changes in β diversity generally reduced the extent of species loss at larger scales to an average of 22\% (ranging from a reduction of 54\% to an increase of 18\%). Our results demonstrate that N enrichment often reduces biodiversity at both local and regional scales, but that a focus on the effects of N enrichment on biodiversity at small spatial scales may often overestimate (and sometimes underestimate) declines in regional biodiversity by failing to recognize the effects of N on β diversity.}, keywords = {LTER-KNZ}, doi = {10.1890/07-0971.1}, author = {Chalcraft, D.R. and Cox, S.B. and Clark, C.M. and E.E Cleland and K.N. Suding and Weiher, E. and Pennington, D.} } @article {KNZ001149, title = {Shrub encroachment in North American grasslands: Shifts in growth form dominance rapidly alters control of ecosystem carbon inputs}, journal = {Global Change Biology}, volume = {14}, year = {2008}, pages = {615 -623}, abstract = {

Shrub encroachment into grass-dominated biomes is occurring globally due to a variety of anthropogenic activities, but the consequences for carbon (C) inputs, storage and cycling remain unclear. We studied eight North American graminoid-dominated ecosystems invaded by shrubs, from arctic tundra to Atlantic coastal dunes, to quantify patterns and controls of C inputs via aboveground net primary production (ANPP). Across a fourfold range in mean annual precipitation (MAP), a key regulator of ecosystem C input at the continental scale, shrub invasion decreased ANPP in xeric sites, but dramatically increased ANPP (\>1000 g m\−2) at high MAP, where shrub patches maintained extraordinarily high leaf area. Concurrently, the relationship between MAP and ANPP shifted from being nonlinear in grasslands to linear in shrublands. Thus, relatively abrupt (\<50 years) shifts in growth form dominance, without changes in resource quantity, can fundamentally alter continental-scale pattern of C inputs and their control by MAP in ways that exceed the direct effects of climate change alone.

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1365-2486.2007.01512.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2486.2007.01512.x}, author = {Alan K. Knapp and J. M. Briggs and Scott. L. Collins and S.R. Archer and Bret-Harte, M.S. and Ewers, B.E. and Peters, D.P. and Young, D.R. and Shaver, G.R. and Pendall, E. and Cleary, M.B.} } @article {KNZ001180, title = {Species responses to nitrogen fertilization in herbaceous plant communities, and associated species traits}, journal = {Ecology}, volume = {89}, year = {2008}, pages = {1175 -}, abstract = {

This synthetic data set contains plant species relative abundance measures from 35 nitrogen (N) fertilization experiments conducted at 10 sites across North America. The data set encompasses the fertilization responses of 575 taxa from 1159 experimental plots. The methodology varied among experiments, in particular with regard to the type and amount of N added, plot size, species composition measure (biomass harvest, pin count, or percent cover), additional experimental manipulations, and experimental duration. At each site, each species has been classified according to a number of easily identified categorical functional traits, including life history, life form, the number of cotyledons, height relative to the canopy, potential for clonal growth, and nativity to the United States. Additional data are available for many sites, indicated by references to publications and web sites. Analyses of these data have shown that N enrichment significantly alters community composition in ways that are predictable on the basis of plant functional traits as well as environmental context. This data set could be used to answer a variety of questions about how plant community composition and structure respond to environmental changes.

}, keywords = {LTER-KNZ}, doi = {10.1890/07-1104.1}, url = {https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/07-1104.1}, author = {Cleland, E.E. and Clark, C.M. and Scott. L. Collins and Fargione, J.E. and Gough, L. and Gross, K.L. and Pennings, S.C. and W.D. Bowman and Robertson, G.P. and Simpson, J. and Tilman, D. and K.N. Suding} } @article {KNZ001164, title = {Stream denitrification across biomes and its response to anthropogenic nitrate loading}, journal = {Nature}, volume = {452}, year = {2008}, pages = {202 -207}, abstract = {

Anthropogenic addition of bioavailable nitrogen to the biosphere is increasing1, 2 and terrestrial ecosystems are becoming increasingly nitrogen-saturated3, causing more bioavailable nitrogen to enter groundwater and surface waters4, 5, 6. Large-scale nitrogen budgets show that an average of about 20\–25 per cent of the nitrogen added to the biosphere is exported from rivers to the ocean or inland basins7, 8, indicating that substantial sinks for nitrogen must exist in the landscape9. Streams and rivers may themselves be important sinks for bioavailable nitrogen owing to their hydrological connections with terrestrial systems, high rates of biological activity, and streambed sediment environments that favour microbial denitrification6, 10, 11. Here we present data from nitrogen stable isotope tracer experiments across 72 streams and 8 regions representing several biomes. We show that total biotic uptake and denitrification of nitrate increase with stream nitrate concentration, but that the efficiency of biotic uptake and denitrification declines as concentration increases, reducing the proportion of in-stream nitrate that is removed from transport. Our data suggest that the total uptake of nitrate is related to ecosystem photosynthesis and that denitrification is related to ecosystem respiration. In addition, we use a stream network model to demonstrate that excess nitrate in streams elicits a disproportionate increase in the fraction of nitrate that is exported to receiving waters and reduces the relative role of small versus large streams as nitrate sinks.

}, keywords = {LTER-KNZ}, doi = {10.1038/nature06686}, url = {https://www.nature.com/articles/nature06686}, author = {Mulholland, P.J. and Helton, A.M. and Poole, G.C. and Hall, R.O. Jr. and Hamilton, S.K. and Peterson, B.J. and Tank, J.L. and L.R. Ashkenas and Cooper, L.W. and Dahm, C.N. and W. K. Dodds and Findlay, S.E.G. and Gregory, S.V. and Grimm, N.B. and Johnson, S.L. and W.H. McDowell and Meyer, J.L. and Valett, H.M. and Webster, J.R. and Arango, C.P. and Beaulieu, J.J. and Bernot, M.J. and Burgin, A.J. and Crenshaw, C. and Johnson, L. and Niederlehner, B.R. and O{\textquoteright}Brien, J.M. and Potter, J.D. and Sheibley, R.W. and Sobota, D.J. and Thomas, S.M.} } @article {KNZ001094, title = {Environmental and plant community determinants ofspecies loss following nitrogen enrichment}, journal = {Ecology Letters}, volume = {10}, year = {2007}, pages = {596 -607}, abstract = {Global energy use and food production have increased nitrogen inputs to ecosystems worldwide, impacting plant community diversity, composition, and function. Previous studies show considerable variation across terrestrial herbaceous ecosystems in the magnitude of species loss following nitrogen (N) enrichment. What controls this variation remains unknown. We present results from 23 N-addition experiments across North America, representing a range of climatic, soil and plant community properties, to determine conditions that lead to greater diversity decline. Species loss in these communities ranged from 0 to 65\% of control richness. Using hierarchical structural equation modelling, we found greater species loss in communities with a lower soil cation exchange capacity, colder regional temperature, and larger production increase following N addition, independent of initial species richness, plant productivity, and the relative abundance of most plant functional groups. Our results indicate sensitivity to N addition is co-determined by environmental conditions and production responsiveness, which overwhelm the effects of initial community structure and composition.}, keywords = {LTER-KNZ}, doi = {10.1111/j.1461-0248.2007.01053.x}, author = {Clark, C.M. and Cleland, E.E. and Scott. L. Collins and Fargione, J.E. and Gough, L. and Pennings, S.C. and K.N. Suding and Grace, J.B.} } @phdthesis {KNZ001096, title = {Genesis and spatial distribution of uplandsoils in east central Kansas}, volume = {PhD Dissertation}, year = {2007}, pages = {1 -704}, school = {Kansas State University}, type = {Ph.D. Thesis}, address = {Manhattan, KS}, abstract = {

Upland soils in east central Kansas have a complex genesis, often contain one or more paleosols, and form in multiple parent materials including loess, colluvium, residuum, and alluvium. Quaternary loess/paleosol investigations have largely ignored this region of Kansas, as the total loess thickness on uplands is \<2 m thick. In this study, the objectives are to examine the morphology and genesis of the soils of interest and how these characteristics vary within soil profiles, across landscapes, and throughout the current series mapping extent. The series of interest include the Irwin, Konza, Dwight, and Ladysmith soil series. Methods used in this study include field descriptions and sampling, terrain analysis, micromorphological investigations, and laboratory characterization, including silt and clay mineralogy. Accelerator mass spectrometry (AMS) was used for numerical dating and determination of stable carbon isotope values (δ13C) for selected paleosols. Radiocarbon ages ranged from 24,000 to 19,000 yr BP and δ13C values were between -19 and -17 \‰ (PDB), indicating that the paleosols were formed in Gilman Canyon loess or the Severance formation, under a mix of C3 and C4 vegetation. Terrain analysis results illustrated that, in given drainage areas, the soil series were mapped on a wide range of slope positions. Field observations and terrain analysis confirmed no relationships between mollic epipedon thickness, solum thickness, paleosol thickness, or depth to the paleosol with respect to landform. Micromorphological investigations revealed increasing soil development with depth, i.e., the presence of two paleosols beneath the modern soil. Mean particle size and mineralogy vary geographically within individual series. Pedogenic carbonate accumulations and redoximorphic concentrations are common features of the soils of interest, and less common features include sodium and gypsum accumulations, slickensides, and redoximorphic depletions. Results from this study will be provided to the USDA-NRCS for use in future soil survey updates, and will contribute to Quaternary loess/paleosol knowledge in Kansas and the Great Plains.

}, keywords = {LTER-KNZ, genesis, kansas, Loess, mapping, Paleosols, soil}, url = {http://hdl.handle.net/2097/288 }, author = {Presley, D.R.} } @article {KNZ001146, title = {Global-scale similarities in nitrogen release patterns during long-term decomposition}, journal = {Science}, volume = {315}, year = {2007}, pages = {361 -364}, abstract = {Litter decomposition provides the primary source of mineral nitrogen (N) for biological activity in most terrestrial ecosystems. A 10-year decomposition experiment in 21 sites from seven biomes found that net N release from leaf litter is dominantly driven by the initial tissue N concentration and mass remaining regardless of climate, edaphic conditions, or biota. Arid grasslands exposed to high ultraviolet radiation were an exception, where net N release was insensitive to initial N. Roots released N linearly with decomposition and exhibited little net N immobilization. We suggest that fundamental constraints on decomposer physiologies lead to predictable global-scale patterns in net N release during decomposition.}, keywords = {LTER-KNZ}, doi = {10.1126/science.1134853}, author = {Parton, W.J. and Silver, W.L. and Burke, I.C. and Grassens, L. and Harmon, M.E. and Currie, W.S. and King, J.Y. and Adair, E.C. and Brandt, L.A. and Hart, S.C. and Fasth, B.} } @article {KNZ001092, title = {Stream insect occupancy-frequency patterns and metapopulation structure}, journal = {Oecologia}, volume = {151}, year = {2007}, pages = {313 -321}, abstract = {An understanding of the distribution patterns of organisms and the underlying factors is a fundamental goal of ecology. One commonly applied approach to visualize these is the analysis of occupancy-frequency patterns. We used data sets describing stream insect distributions from different regions of North America to analyze occupancy-frequency patterns and assess the effects of spatial scale, sampling intensity, and taxonomic resolution on these patterns. Distributions were dominated by satellite taxa (those occurring in <=10\% of sites), whereas the occurrence of core taxa (occurring in >=90\% of sites) determined the overall modality of occupancy-frequency patterns. The proportions of satellite taxa increased with spatial scale and showed positive relationships with sampling intensity (r 2=0.74{\textendash}0.96). Furthermore, analyses of data sets from New York (USA) showed that generic-level assessments underestimated the satellite class and occasionally shifted occupancy-frequency distributions from unimodal to bimodal. Our results indicate that, regardless of species- or generic-level taxonomy, stream insect communities are characterized by satellite species and that the proportion of satellite species increases with spatial scale and sampling intensity. Thus, niche-based models of occupancy-frequency patterns better characterize stream insect communities than metapopulation models such as the core-satellite species hypothesis.}, keywords = {LTER-KNZ, aquatic insect, Core-satellite, Distribution, Sampling intensity, spatial scale}, doi = {10.1007/s00442-006-0596-8}, author = {Heatherly, T. and M.R. Whiles and D.J. Gibson and Scott. L. Collins and Huryn, A.D. and Jackson, J.K. and Palmer, M.A.} } @article {KNZ001109, title = {Effects of floods on fish assemblages in an intermittent prairie stream}, journal = {Freshwater Biology}, volume = {51}, year = {2006}, pages = {2072 -2086}, abstract = {1. Floods are major disturbances to stream ecosystems that can kill or displace organisms and modify habitats. Many studies have reported changes in fish assemblages after a single flood, but few studies have evaluated the importance of timing and intensity of floods on long-term fish assemblage dynamics. 2. We used a 10-year dataset to evaluate the effects of floods on fishes in Kings Creek, an intermittent prairie stream in north-eastern, Kansas, U.S.A. Samples were collected seasonally at two perennial headwater sites (1995{\textendash}2005) and one perennial downstream flowing site (1997{\textendash}2005) allowing us to evaluate the effects of floods at different locations within a watershed. In addition, four surveys during 2003 and 2004 sampled 3{\textendash}5 km of stream between the long-term study sites to evaluate the use of intermittent reaches of this stream. 3. Because of higher discharge and bed scouring at the downstream site, we predicted that the fish assemblage would have lowered species richness and abundance following floods. In contrast, we expected increased species richness and abundance at headwater sites because floods increase stream connectivity and create the potential for colonisation from downstream reaches. 4. Akaike Information Criteria (AIC) was used to select among candidate regression models that predicted species richness and abundance based on Julian date, time since floods, season and physical habitat at each site. At the downstream site, AIC weightings suggested Julian date was the best predictor of fish assemblage structure, but no model explained >16\% of the variation in species richness or community structure. Variation explained by Julian date was primarily attributed to a long-term pattern of declining abundance of common species. At the headwater sites, there was not a single candidate model selected to predict total species abundance and assemblage structure. AIC weightings suggested variation in assemblage structure was associated with either Julian date or local habitat characteristics. 5. Fishes rapidly colonised isolated or dry habitats following floods. This was evidenced by the occurrence of fishes in intermittent reaches and the positive association between maximum daily discharge and colonisation events at both headwater sites. 6. Our study suggests floods allow dispersal into intermittent habitats with little or no downstream displacement of fishes. Movement of fishes among habitats during flooding highlights the importance of maintaining connectivity of stream networks of low to medium order prairie streams.}, keywords = {LTER-KNZ}, doi = {10.1111/j.1365-2427.2006.01640.x}, author = {Franssen, N.R. and K. B. Gido and Strakosh, T.R. and Bertrand, K.N. and Franssen, C.M. and Paukert, C.P. and Pitts, K.L. and Guy, C.S. and Tripe, J.A. and Shrank, S.J.} } @article {KNZ001047, title = {Effects of prescribed burns and bison (Bos bison)grazing on breeding bird abundances in tallgrass prairie}, journal = {Auk}, volume = {123}, year = {2006}, pages = {183 -197}, abstract = {Grassland birds have declined more than any other avian assemblage in North America, with nearly every species showing negative population trends. In the Flint Hills of Kansas, the largest remnant of the tallgrass prairie biome, annual spring burning of rangeland has recently replaced burning every 2{\textendash}3 years. I examined effects of different burning and bison (Bos bison) grazing regimes on June abundances of seven bird species using a 23-year data set from the Konza Prairie Biological Station. Fire significantly affected the abundances of six of the seven species. Effects varied among species but, notably, four grass-dependent species{\textemdash}Grasshopper Sparrow (Ammodramus savannarum), Henslow{\textquoteright}s Sparrow (A. henslowii), Dickcissel (Spiza americana), and Eastern Meadowlark (Sturnella magna){\textemdash} and the shrub-dependent Bell{\textquoteright}s Vireo (Vireo bellii){\textemdash}were least abundant or absent at sites in the breeding season immediately following burning. Upland Sandpipers (Bartramia longicauda) were most abundant at sites in the season following burning, whereas Brown-headed Cowbirds (Molothrus ater) exhibited no significant response. Bison grazing increased abundance of Upland Sandpiper and Grasshopper Sparrow, nearly eliminated Henslow{\textquoteright}s Sparrow, and (in combination with recent fire) lowered the abundance of Dickcissel. Although fire and grazing are natural forces that maintain tallgrass prairie, their action was, until recently, intermittent and patchy, providing grassland birds with a variety of levels of disturbance. If the vast Flint Hills prairie is to serve as a grassland bird stronghold, the region-wide practice of annual burning with intensive grazing must be replaced with alternatives that restore heterogeneity to the landscape.}, keywords = {LTER-KNZ}, doi = {10.1642/0004-8038(2006)123[0183:EOPBAB]2.0.CO;2}, author = {Powell, A.F.L.A.} } @article {KNZ001065, title = {Impact of hydroclimatic fluctuations on the soil water balance}, journal = {Water Resources Research}, volume = {42}, year = {2006}, pages = {4606 -}, abstract = {[1] We analyze the propagation of daily fluctuations in rainfall and potential evapotranspiration to soil moisture dynamics, using a stochastic model that accounts for these two different forms of hydroclimatic variability. The pulsing, intermittent behavior of daily precipitation is described by a compound Poisson process that models the unpredictability of both frequency and amount of rainfall events, while fluctuations in potential evapotranspiration that act continuously in time are assumed to be Gaussian. The resulting model for the soil water balance is thus a stochastic differential equation, forced by a state-dependent compound Poisson noise and a multiplicative Gaussian noise. Steady state probability distribution functions (pdfs) of soil moisture are obtained analytically along with the equations for the expected water balance and its variability. The multiplicative effect of temporal fluctuations in potential evapotranspiration on soil moisture reduces the soil water losses caused by evapotranspiration compared to the case when they are not present. Most importantly, the analysis also shows that because of their different forms and state dependence the impact of rainfall variability on soil moisture dynamics is much more significant than that of potential evapotranspiration, the fluctuations of which do not affect appreciably the soil moisture statistical properties.}, keywords = {LTER-KNZ}, doi = {10.1029/2005WR004606}, author = {Daly, E. and Porporato, A.} } @article {KNZ001153, title = {MODIS land cover and LAI collection 4 product quality across nine sites in the western hemisphere}, journal = {IEEE Transactions in Geosciences and Remote Sensing}, volume = {44}, year = {2006}, pages = {1843 -1857}, abstract = {Global maps of land cover and leaf area index (LAI) derived from the Moderate Resolution Imaging Spectrometer (MODIS) reflectance data are an important resource in studies of global change, but errors in these must be characterized and well understood. Product validation requires careful scaling from ground and related measurements to a grain commensurate with MODIS products. We present an updated BigFoot project protocol for developing 25-m validation data layers over 49-km2 study areas. Results from comparisons of MODIS and BigFoot land cover and LAI products at nine contrasting sites are reported. In terms of proportional coverage, MODIS and BigFoot land cover were in close agreement at six sites. The largest differences were at low tree cover evergreen needleleaf sites and at an Arctic tundra site where the MODIS product overestimated woody cover proportions. At low leaf biomass sites there was reasonable agreement between MODIS and BigFoot LAI products, but there was not a particular MODIS LAI algorithm pathway that consistently compared most favorably. At high leaf biomass sites, MODIS LAI was generally overpredicted by a significant amount. For evergreen needleleaf sites, LAI seasonality was exaggerated by MODIS. Our results suggest incremental improvement from Collection 3 to Collection 4 MODIS products, with some remaining problems that need to be addressed}, keywords = {LTER-KNZ}, doi = {10.1109/TGRS.2006.876026}, author = {Cohen, W.B. and Maiersperger, T.K. and Turner, D.P. and Ritts, W.D. and Pflugmacher, D. and Kennedy, R.E. and Kirschbaum, A. and Running, S.W. and Costa, M. and Gower, S.T.} } @article {KNZ001077, title = {Nest desertion bya cowbird host: an anti-parasite behavior or a response to egg loss?}, journal = {Behavioral Ecology}, volume = {17}, year = {2006}, pages = {917 -924}, abstract = {Natural selection can favor songbirds that desert nests containing eggs of the parasitic brown-headed cowbird (Molothrus ater). However, the high variability in desertion of parasitized nests within species is perplexing in light of the typically high costs of parasitism. Because nest desertion can also be a response to partial clutch predation, we first asked if Bell{\textquoteright}s vireos (Vireo bellii) deserted nests in response to the presence of cowbird eggs (antiparasite response hypothesis) or to egg removal by predators and female cowbirds (egg predation hypothesis). Second, we asked whether variation in nest desertion was due to intrinsic differences among individuals or to variation in nest contents. We monitored a large number of nests (n = 494) and performed a clutch manipulation experiment to test these hypotheses. The number of vireo eggs that remained in a nest was a strong predictor of desertion both within and among pairs. Neither the presence of a single cowbird egg, which leads to nest failure for this host, nor the number of cowbird eggs received in a vireo nest influenced nest desertion. Furthermore, vireos did not desert experimental nests when we immediately exchanged cowbird eggs for vireo eggs but deserted if we removed vireo eggs and replaced them with cowbird eggs the following morning. Desertion of parasitized nests by Bell{\textquoteright}s vireos can be almost entirely explained as a response to partial or complete clutch loss and does not appear to have been altered by selection from brood parasitism.}, keywords = {LTER-KNZ, Bell{\textquoteright}s Vireo, brown-headed cowbird, egg predation, evolutionary lag, host{\textendash}parasite coevolution, Molothrus ater, Vireo bellii}, doi = {10.1093/beheco/arl025}, author = {Kosciuch, K.L. and Parker, T.H. and Sandercock, B.K.} } @article {KNZ001107, title = {Sentinel nematodes of land-use change and restoration in tallgrass prairie}, journal = {Journal of Nematology}, volume = {38}, year = {2006}, pages = {20 -27}, abstract = {Changes in land use and the associated changes in land cover are recognized as the most important component of human-induced global change. Much attention has been focused on deforestation, but grasslands are among the most endangered ecosystems on Earth. The North American tallgrass prairie is a dramatic example, exhibiting a greater than 95\% decline in historical area. Renewed interest in prairie conservation and restoration has highlighted the need for ecological indicators of disturbance and recovery in native systems, including the belowground component. The tallgrass prairie differs from the agricultural systems that have replaced it in having greater diversity and heterogeneity of resources, less physical soil disturbance (although other disturbances, such as fire and grazing, are prominent), and greater nitrogen limitation. Understanding the responses of nematode taxa to these characteristic differences is crucial to the development and improvement of community indices, but while knowledge of disturbance responses by individual taxa is accumulating, the level of necessary taxonomic resolution remains in question. Although nematode communities generally are better described for temperate grasslands than for other natural ecosystems, identification of sentinel taxa is further confounded by high levels of diversity, and both spatial and temporal heterogeneity.}, keywords = {LTER-KNZ}, url = {http://www.ncbi.nlm.nih.gov/pubmed/19259426}, author = {Todd, T.C. and Powers, T.O. and Mullin, P.G.} } @article {KNZ001061, title = {Superstatistics of hydro-climatic fluctuations and interannual ecosystem productivity}, journal = {Geophysical Research Letters}, volume = {33}, year = {2006}, pages = {15402 -}, abstract = {[1] Ecosystems driven by hydro-climatic fluctuations at different time scales can be interpreted as non-equilibrium dynamical systems. Here we explore the propagation of daily and interannual rainfall fluctuations through the soil-plant system using the theory of superstatistics. With the help of simplified stochastic models of rainfall, we show how interactions of daily and interannual rainfall fluctuations may qualitatively change the probability distributions of rainfall toward higher frequencies of extreme droughts and intense storms. This in turn is likely to induce marked changes in productivity of mesic ecosystems, while more xeric ecosystems might be insensitive or even benefit from them. This study provides a theoretical basis for predictions of ecosystem responses to the increased precipitation variability expected in future North American climate regimes.}, keywords = {LTER-KNZ}, doi = {10.1029/2006GL026412}, author = {Porporato, A. and Vico, G. and Fay, P.A.} } @article {KNZ00977, title = {Do individual plant speciesshow predictable responses to nitrogen addition across multipleexperiments?}, journal = {Oikos}, volume = {110}, year = {2005}, pages = {547 -555}, abstract = {A number of experiments have addressed how increases in nitrogen availability increase the productivity and decrease the diversity of plant communities. We lack, however, a rigorous mechanistic understanding of how changes in abundance of particular species combine to produce changes in community productivity and diversity. Single experiments cannot provide insight into this issue because each species occurs only once per experiment, and each experiment is conducted in only one location; thus, it is impossible from single experiments to determine whether responses of particular species are consistent across environments or dependent on the particular environmental context in which the experiment was conducted. To address this issue, we assembled a dataset of 20 herbaceous species that were each represented in at least 6 different fertilization experiments and tested whether responses were general across experiments. Of the 20 species, one consistently increased in relative abundance and five consistently decreased across replicate experiments. A partially-overlapping group of 8 species displayed responses to nitrogen that varied predictably among experiments as a function of geographic location, neighboring species, or a handful of other community characteristics (ANPP, precipitation, species richness, relative abundance of focal species in control plots, and community composition). Thus, despite modest replication and a limited number of predictor variables, we were able to identify consistent patterns in response of 10 out of 20 species across multiple experiments. We conclude that the responses of individual species to nitrogen addition are often predictable, but that in most cases these responses are functions of the abiotic or biotic environment. Thus, a rigorous understanding of how plant species respond to nitrogen addition will have to consider not only the traits of individual plant species, but also aspects of the communities in which those plants live.}, keywords = {LTER-KNZ}, doi = {10.1111/j.0030-1299.2005.13792.x}, author = {Pennings, S.C. and Clark, C.M. and Cleland, E.E. and Scott. L. Collins and Gough, L. and Gross, K.L. and Milchunas, D.G. and K.N. Suding} } @article {KNZ00988, title = {Estimation of stream nutrient uptake from nutrient addition experiments}, journal = {Limnology and Oceanography Methods}, volume = {3}, year = {2005}, pages = {174 -182}, abstract = {Nutrient uptake in streams is often quantified by determining nutrient uptake length. However, current methods for measuring nutrient uptake length are often impractical, expensive, or demonstrably incorrect. We have developed a new method to estimate ambient nutrient uptake lengths using field experiments involving several levels of nutrient addition. Data analysis involves plotting nutrient addition uptake lengths versus added concentration and extrapolating to the negative ambient concentration. This method is relatively easy, inexpensive, and based on sound theoretical development. It is more accurate than the commonly used method involving a single nutrient addition. The utility of the method is supported by field studies directly comparing our new method with isotopic tracer methods for determining uptake lengths of phosphorus, ammonium, and nitrate. Our method also provides parameters for comparing potential nutrient limitation among streams.}, keywords = {LTER-KNZ}, doi = {10.4319/lom.2005.3.174}, author = {Payn, R.A. and Webster, J.R. and Mulholland, P.J. and Valett, H.M. and W. K. Dodds} } @article {KNZ00967, title = {Functional and abundance based mechanisms explain diversity loss due to nitrogen fertilization}, journal = {Proceedings of the National Academy of Sciences}, volume = {102}, year = {2005}, pages = {4387 -4392}, abstract = {Human activities have increased N availability dramatically in terrestrial and aquatic ecosystems. Extensive research demonstrates that local plant species diversity generally declines in response to nutrient enrichment, yet the mechanisms for this decline remain unclear. Based on an analysis of >900 species responses from 34 N-fertilization experiments across nine terrestrial ecosystems in North America, we show that both trait-neutral and trait-based mechanisms operate simultaneously to influence diversity loss as production increases. Rare species were often lost because of soil fertilization, randomly with respect to traits. The risk of species loss due to fertilization ranged from >60\% for the rarest species to 10\% for the most abundant species. Perennials, species with N-fixing symbionts, and those of native origin also experienced increased risk of local extinction after fertilization, regardless of their initial abundance. Whereas abundance was consistently important across all systems, functional mechanisms were often system-dependent. As N availability continues to increase globally, management that focuses on locally susceptible functional groups and generally susceptible rare species will be essential to maintain biodiversity.}, keywords = {LTER-KNZ}, doi = {10.1073/pnas.0408648102}, author = {K.N. Suding and Scott. L. Collins and Gough, L. and Clark, C.M. and Cleland, E.E. and Gross, K.L. and Milchunas, D.G. and Pennings, S.} } @article {KNZ001011, title = {Simulated carbon sink response of shortgrass steppe, tallgrass prairie and forest ecosystems to rising [CO2], temperature and nitrogen input}, journal = {Global Biogeochemical Cycles}, volume = {19}, year = {2005}, pages = {1 -}, abstract = {[1] The response of plant ecosystems to environmental change will determine whether the terrestrial biosphere will remain a substantial carbon sink or become a source during the next century. We use two ecosystem models, the Generic Decomposition And Yield model (G{\textquoteright}DAY) and the daily time step version of the Century model (DAYCENT), to simulate net ecosystem productivity (NEP) for three contrasting ecosystems (shortgrass steppe in Colorado, tallgrass prairie in Kansas, and Norway spruce in Sweden) with varying degrees of water, temperature, and nutrient limitation, to determine responses to gradual increases in atmospheric CO2 concentration ([CO2]), temperature, and nitrogen input over 100 years. Using G{\textquoteright}DAY, under rising [CO2], there is evidence of C sink {\textquotedblleft}saturation,{\textquotedblright} defined here as positive NEP reaching an upper limit and then declining toward zero, at all three sites (due largely to increased N immobilization in soil organic matter) but a positive C sink is sustained throughout the 100 years. DAYCENT also predicts a sustained C sink at all three sites under rising [CO2], with evidence of C sink saturation for the Colorado grassland and the C sink levels off after 80 years for the Kansas grassland. Warming reduces soil C and the C sink in both grassland ecosystems but increases the C sink in the forest. Warming increases decomposition and soil N mineralization, which stimulates net primary productivity (NPP) at all sites except when inducing water limitation. At the forest site some of the enhanced N release is allocated to a woody biomass pool with a low N:C ratio so that warming enhances NEP without increased N input at the forest site, but not at the grassland sites. Responses to combinations of treatments are generally additive for DAYCENT but more interactive for G{\textquoteright}DAY, especially under combined rising [CO2] and warming at the strongly water- and N-limited shortgrass steppe. Increasing N input alleviates C sink saturation and enhances NEP, NPP, and soil C at all sites. At the water-limited grassland sites the effect of rising [CO2] on growth is greatest during the drier seasons. Key sensitivities in the simulations of NEP are identified and include NPP sensitivity to gradual increase in [CO2], N immobilization as a long-term feedback, and the presence or not of plant biomass pools with low N:C ratio.}, keywords = {LTER-KNZ}, doi = {10.1029/2004GB002226}, author = {Pepper, D.A. and Del Grosso, S.J. and McMurtrie, R.E. and Parton, W.J.} } @article {KNZ00898, title = {Barley yellow dwarf disease in natural populations of dominant tallgrass prairie species in Kansas}, journal = {Plant Disease}, volume = {88}, year = {2004}, pages = {574 -}, abstract = {The grasses Sorghastrum nutans (Indian grass), Schizachyrium scoparium (little bluestem), Panicum virgatum (switchgrass), and Andropogon gerardii (big bluestem) are four of the most common plant species present in a tallgrass prairie (1). Infection with barley yellow dwarf virus (BYDV, family Luteoviridae) is of interest in these species because of the potential effects of the virus on tallgrass prairie plant communities and the potential for tallgrass prairie to function as a reservoir of the virus for infection in wheat or barley fields. In a previous inoculation experiment, an unidentified strain of BYDV transmitted by the aphid species Rhopalosiphum padi was reported to infect S. scoparium but none of the other three grass species (2). We sampled for the presence of five virus strains in at least 50 blooming plants of each grass species in a natural tallgrass prairie stand in August 2000. Samples were collected in watersheds that were designated 1B, 1D, K1A, 20B, and 20C at Konza Prairie Biological Station in the Flint Hills near Manhattan, KS. To detect the virus, we used enzyme-linked immunosorbent assay (ELISA) with antibodies purchased from Agdia (Elkhart, IN). For the PAV, MAV, RMV, and SGV strains, we used double-antibody sandwich ELISA with alkaline phosphatase label. For Cereal yellow dwarf virus (RPV), we used compound direct ELISA with alkaline phosphatase label. The scoring of ELISA results was based on comparison with infected and uninfected control plants of the same species. Symptoms of infection in the field were difficult to interpret visually, since plants in this natural environment often showed multiple symptoms of stress. None of the five strains were detected in 51 individuals of S. nutans. For 50 individuals of S. scoparium, the incidence of infection by the different strains was 4\% for MAV, 0\% for PAV, 2\% for RMV, 0\% for RPV, and 58\% for SGV. For 51 individuals of P. virgatum, the incidence of infection was 31\% for MAV, 0\% for PAV, 0\% for RMV, 0\% for RPV, and 4\% for SGV. For 64 individuals of A. gerardii, the incidence of infection was 59\% for MAV, 0\% for PAV, 0\% for RMV, 0\% for RPV, and 3\% for SGV. The impact of BYDV on these tallgrass prairie species remains to be determined. The PAV strain is the most commonly reported strain in wheat in Kansas but was not recovered from these grass species.}, keywords = {LTER-KNZ}, doi = {10.1094/PDIS.2004.88.5.574B}, author = {Garrett, K.A. and Dendy, S.P. and Power, A.G. and Blaisdell, G.K. and Alexander, H.M. and McCarron, J.K.} } @article {KNZ00925, title = {Carbon and nitrogen stoichiometry and nitrogen cycling rates in streams}, journal = {Oecologia}, volume = {140}, year = {2004}, pages = {458 -467}, abstract = {Stoichiometric analyses can be used to investigate the linkages between N and C cycles and how these linkages influence biogeochemistry at many scales, from components of individual ecosystems up to the biosphere. N-specific NH4 + uptake rates were measured in eight streams using short-term 15N tracer additions, and C to N ratios (C:N) were determined from living and non-living organic matter collected from ten streams. These data were also compared to previously published data compiled from studies of lakes, ponds, wetlands, forests, and tundra. There was a significant negative relationship between C:N and N-specific uptake rate; C:N could account for 41\% of the variance in N-specific uptake rate across all streams, and the relationship held in five of eight streams. Most of the variation in N-specific uptake rate was contributed by detrital and primary producer compartments with large values of C:N and small values for N-specific uptake rate. In streams, particulate materials are not as likely to move downstream as dissolved N, so if N is cycling in a particulate compartment, N retention is likely to be greater. Together, these data suggest that N retention may depend in part on C:N of living and non-living organic matter in streams. Factors that alter C:N of stream ecosystem compartments, such as removal of riparian vegetation or N fertilization, may influence the amount of retention attributed to these ecosystem compartments by causing shifts in stoichiometry. Our analysis suggests that C:N of ecosystem compartments can be used to link N-cycling models across streams.}, keywords = {LTER-KNZ, carbon, Carbon:Nitrogen ratio, nitrogen, stoichiometry, streams}, doi = {10.1007/s00442-004-1599-y}, author = {W. K. Dodds and Marti, E. and Tank, J. and Pontius, J.L. and Hamilton, S.K. and Grimm, N.B. and W.B. Bowden and W.H. McDowell and Peterson, B.J. and Valett, H.M. and Webster, J.R. and Gregory, S.} } @article {KNZ00917, title = {Convergence across biomes to a common rain-use efficiency}, journal = {Nature}, volume = {429}, year = {2004}, pages = {651 -654}, keywords = {LTER-KNZ}, doi = {10.1038/nature02561}, author = {Huxman, T.E. and M.D. Smith and Fay, P.A. and Alan K. Knapp and Shaw, M.R. and Loik, M.E. and Smith, S.D. and Tissue, D.T. and Zak, J.C. and Weltzin, J.F. and Pockman, W.T. and Sala, O.E. and Haddad, B.M. and Harte, J. and Koch, G.W. and Schwinning, S. and Small, E.E. and Williams, D.G.} } @article {KNZ00996, title = {Effects of food supplementation on female nest attentiveness and incubation Mate-feeding in two sympatric wren species}, journal = {Wilson Bulletin}, volume = {116}, year = {2004}, pages = {23 -30}, abstract = {We examined effects of incubation mate feeding on female incubation behavior and correlates of fitness by providing female Bewick{\textquoteright}s Wrens (Thryomanes bewickii) and House Wrens (Troglodytes aedon) with food supplements. Males of these species vary in their rates of feeding; Bewick{\textquoteright}s Wrens feed their incubating mates frequently, whereas House Wrens seldom engage in this behavior. Average length of incubation bout and nest attentiveness (proportion of time spent on the nest) were higher for supplemented female Bewick{\textquoteright}s Wrens and House Wrens compared to controls. Furthermore, mates of supplemented Bewick{\textquoteright}s Wrens provisioned females at lower rates than controls, and their rate of feeding was inversely correlated with ambient temperature. Incubation length and hatching success were not significantly different between treatments for either species. These results suggest that incubation mate feeding can increase female nest attentiveness and perhaps enhance fitness of both males and females. In House Wrens, potential tradeoffs between the benefits of parental care and opportunities to obtain additional mates may explain why males rarely feed incubating females.}, keywords = {LTER-KNZ}, doi = {10.1676/0043-5643(2004)116[0023:EOFSOF]2.0.CO;2}, author = {Pearse, A.T. and Cavitt, J.F. and Cully, J.F.} } @mastersthesis {KNZ00987, title = {Effects of prescribed burning and grazingon breeding bird abundances in tallgrass prairie}, volume = {MS Thesis}, year = {2004}, pages = {1 -34}, school = {University of Kansas}, type = {M.S. Thesis}, address = {Lawrence, KS}, keywords = {LTER-KNZ}, url = {https://bioone.org/journals/The-Auk/volume-123/issue-1/0004-8038(2006)123[0183:EOPBAB]2.0.CO;2/EFFECTS-OF-PRESCRIBED-BURNS-AND-BISON-BOS-BISON-GRAZING-ON/10.1642/0004-8038(2006)123[0183:EOPBAB]2.0.CO;2.full}, author = {Powell, A.F.L.A.} } @article {KNZ00900, title = {Fire effects on mycorrhizal symbiosis and root system architecture in southern African savanna grasses}, journal = {African Journal of Ecology}, volume = {42}, year = {2004}, pages = {1 -10}, abstract = {Mycorrhizal symbiosis is a key factor influencing aspects of grassland and savanna structure and functioning including plant growth, competition, population and community dynamics, and responses to fire and herbivory. This study assessed the effects of fire on mycorrhizal symbiosis and root system architecture (RSA) in South African savanna grasses. Eighteen grass species were sampled across contrasting fire frequency treatments in the Kruger National Park experimental burn plots. All eighteen species studied were highly colonized by arbuscular mycorrhizal fungi (AMF). Both mycorrhizal symbiosis and RSA were strongly affected by fire, with an increase in AMF colonization and a decrease in root branching and fine root development with decreasing fire frequency. Greater water limitation in frequently burned savanna may result in greater fine root development, thus reducing plant dependency on AMF for acquisition of soil resources. Reduced mycorrhizal colonization in frequently burned savanna may also be driven by higher phosphorus : nitrogen ratios, or indirect effects related to higher grazing intensities in frequently burned sites.}, keywords = {LTER-KNZ, fire, Grasses, mycorrhizas, root architecture, Savannas}, doi = {10.1111/j.1365-2028.2004.00533.x}, author = {D.C. Hartnett and Potgieter, A.L.F. and G.T. Wilson} } @article {KNZ00943, title = {Generality in ecology: testing North American grassland rules in South African savannas}, journal = {Frontiers in Ecology and the Environment}, volume = {9}, year = {2004}, pages = {483 -491}, abstract = {Ecology has emerged as a global science, and there is a pressing need to identify ecological rules {\textendash} general principles that will improve its predictive capability for scientists and its usefulness for managers and policy makers. Ideally, the generality and limits of these ecological rules should be assessed using extensive, coordinated experiments that ensure consistency in design and comparability of data. To improve the design of these large-scale efforts, existing data should be used to test prospective ecological rules and to identify their limits and contingencies. As an example of this approach, we describe prospective rules for grassland responses to fire and rainfall gradients, identified from long-term studies of North American grasslands and tested with existing data from long-term experiments in South African savanna grasslands. Analyses indicated consistent effects of fire on the abundance of the dominant (grasses) and subdominant (forbs) flora on both continents, but no common response of grass or forb abundance across a rainfall gradient. Such analyses can inform future research designs to refine and more explicitly test ecological rules.}, keywords = {LTER-KNZ}, doi = {10.1890/1540-9295(2004)002[0483:GIETNA]2.0.CO;2}, author = {Alan K. Knapp and M.D. Smith and Scott. L. Collins and Zambatis, N. and Peel, M. and Emery, S.M. and Wojdak, J. and Horner-Devine, M.C. and Biggs, H. and Kruger, J. and Andelman, S.J.} } @article {KNZ00840, title = {Needed: A unified infrastructure to support long-term scientific research on public lands}, journal = {Ecological Applications}, volume = {14}, year = {2004}, pages = {18 -21}, keywords = {LTER-KNZ}, doi = {10.1890/03-5106}, author = {Pringle, C.M. and Scott. L. Collins} } @article {KNZ00920, title = {Water relations in grassland and desert ecosystems exposed to elevated atmospheric CO2}, journal = {Oecologia}, volume = {140}, year = {2004}, pages = {11 -25}, abstract = {

Atmospheric CO2 enrichment may stimulate plant growth directly through (1) enhanced photosynthesis or indirectly, through (2) reduced plant water consumption and hence slower soil moisture depletion, or the combination of both. Herein we describe gas exchange, plant biomass and species responses of five native or semi-native temperate and Mediterranean grasslands and three semi-arid systems to CO2 enrichment, with an emphasis on water relations. Increasing CO2 led to decreased leaf conductance for water vapor, improved plant water status, altered seasonal evapotranspiration dynamics, and in most cases, periodic increases in soil water content. The extent, timing and duration of these responses varied among ecosystems, species and years. Across the grasslands of the Kansas tallgrass prairie, Colorado shortgrass steppe and Swiss calcareous grassland, increases in aboveground biomass from CO2 enrichment were relatively greater in dry years. In contrast, CO2-induced aboveground biomass increases in the Texas C3/C4 grassland and the New Zealand pasture seemed little or only marginally influenced by yearly variation in soil water, while plant growth in the Mojave Desert was stimulated by CO2 in a relatively wet year. Mediterranean grasslands sometimes failed to respond to CO2-related increased late-season water, whereas semiarid Negev grassland assemblages profited. Vegetative and reproductive responses to CO2 were highly varied among species and ecosystems, and did not generally follow any predictable pattern in regard to functional groups. Results suggest that the indirect effects of CO2 on plant and soil water relations may contribute substantially to experimentally induced CO2-effects, and also reflect local humidity conditions. For landscape scale predictions, this analysis calls for a clear distinction between biomass responses due to direct CO2 effects on photosynthesis and those indirect CO2 effects via soil moisture as documented here.

}, keywords = {LTER-KNZ, biomass, Carbon dioxide enrichment, Landscape predictions, soil water, Stomata}, doi = {10.1007/s00442-004-1550-2}, author = {Morgan, J.A. and Pataki, D.E. and Korner, C. and Clark, H. and Del Grosso, S.J. and Grunzweig, J.M. and Alan K. Knapp and Mosier, A.R. and Newton, P.C.D. and Niklaus, P.A. and Jesse B. Nippert and Nowak, R.S. and Parton, W.J. and Polley, H.W. and Shaw, M.R.} } @article {KNZ00881, title = {Assessing the response of terrestrial ecosystems to potential changes in precipitation}, journal = {BioScience}, volume = {53}, year = {2003}, pages = {941 -952}, abstract = {Changes in Earth{\textquoteright}s surface temperatures caused by anthropogenic emissions of greenhouse gases are expected to affect global and regional precipitation regimes. Interactions between changing precipitation regimes and other aspects of global change are likely to affect natural and managed terrestrial ecosystems as well as human society. Although much recent research has focused on assessing the responses of terrestrial ecosystems to rising carbon dioxide or temperature, relatively little research has focused on understanding how ecosystems respond to changes in precipitation regimes. Here we review predicted changes in global and regional precipitation regimes, outline the consequences of precipitation change for natural ecosystems and human activities, and discuss approaches to improving understanding of ecosystem responses to changing precipitation. Further, we introduce the Precipitation and Ecosystem Change Research Network (PrecipNet), a new interdisciplinary research network assembled to encourage and foster communication and collaboration across research groups with common interests in the impacts of global change on precipitation regimes, ecosystem structure and function, and the human enterprise.}, keywords = {LTER-KNZ, Community, ecosystem, global change, Precipitation, soil moisture}, doi = {doi: 10.1641/0006-3568(2003)053[0941:ATROTE]2.0.CO;2}, author = {Weltzin, J.F. and Loik, M.E. and Schwinning, S. and Williams, D.G. and Fay, P.A. and Haddad, B. and Harte, J. and Huxman, T.E. and Alan K. Knapp and Lin, G. and Pockman, W.T. and Shaw, M.R. and Small, E. and M.D. Smith and Tissue, D.T. and Zak, J.C.} } @article {KNZ00870, title = {Factors affecting ammonium uptake in streams - an inter-biome perspective}, journal = {Freshwater Biology}, volume = {48}, year = {2003}, pages = {1329 -1352}, abstract = {1. The Lotic Intersite Nitrogen eXperiment (LINX) was a coordinated study of the relationships between North American biomes and factors governing ammonium uptake in streams. Our objective was to relate inter-biome variability of ammonium uptake to physical, chemical and biological processes. 2. Data were collected from 11 streams ranging from arctic to tropical and from desert to rainforest. Measurements at each site included physical, hydraulic and chemical characteristics, biological parameters, whole-stream metabolism and ammonium uptake. Ammonium uptake was measured by injection of 15N-ammonium and downstream measurements of 15N-ammonium concentration. 3. We found no general, statistically significant relationships that explained the variability in ammonium uptake among sites. However, this approach does not account for the multiple mechanisms of ammonium uptake in streams. When we estimated biological demand for inorganic nitrogen based on our measurements of in-stream metabolism, we found good correspondence between calculated nitrogen demand and measured assimilative nitrogen uptake. 4. Nitrogen uptake varied little among sites, reflecting metabolic compensation in streams in a variety of distinctly different biomes (autotrophic production is high where allochthonous inputs are relatively low and vice versa). 5. Both autotrophic and heterotrophic metabolism require nitrogen and these biotic processes dominate inorganic nitrogen retention in streams. Factors that affect the relative balance of autotrophic and heterotrophic metabolism indirectly control inorganic nitrogen uptake.}, keywords = {LTER-KNZ}, doi = {10.1046/j.1365-2427.2003.01094.x}, author = {Webster, J.R. and P. Mulholland and Tank, J.L. and Valett, H.M. and W. K. Dodds and Peterson, B.J. and W.B. Bowden and Dahm, C.N. and S.E.G. Findlay and Gregory, S.V. and Grimm, N.B. and Hamilton, S.K. and Johnson, S.L. and Marti, E. and W.H. McDowell and Meyer, J.L. and Morrall, D.D. and Thomas, S.A. and Wollheim, W.M.} } @article {KNZ00875, title = {Relationships at the aboveground-belowground interface: Plants, soil biota, and soil processes}, journal = {Ecological Monographs}, volume = {73}, year = {2003}, pages = {377 -395}, abstract = {Interactions at the aboveground{\textendash}belowground interface provide important feedbacks that regulate ecosystem processes. Organisms within soil food webs are involved in processes of decomposition and nutrient mineralization, and their abundance and activity have been linked to plant ecophysiological traits such as species identity and the quality and quantity of plant tissue. We tested aboveground{\textendash}belowground diversity relationships in a naturally developed plant community of native tallgrass prairie by taking soil samples from beneath naturally established grass tillers of chosen characteristics (e.g., homogeneous vs. heterogeneous plant combinations or C4 vs. C3 photosynthetic pathway) without imposing any disturbances to existing plant{\textendash}soil relationships. The goal of this study was to elucidate the consequences, for soil microbiota (microflora phospholipid fatty acids, protozoa, and nematode functional groups) and for C and N mineralization, of plant community properties such as species richness, resource quality, resource heterogeneity, species identity, and presence of exotics. None of the biotic or abiotic soil variables was related to plant resource heterogeneity. Protozoa were not responsive to any of the plant community traits. Some bacterial and nematode groups were affected by plant characteristics specific to a particular plant species, but no uniform pattern emerged. Invasive and native plants generally were similar with respect to soil variables tested in this study. The lack of clear responses of soil variables to plant community traits indicates that idiosyncratic effects dominate both at the plant and soil biotic level and that generalized plant and soil diversity effects are hard to predict.}, keywords = {LTER-KNZ}, doi = {10.1890/0012-9615(2003)073[0377:RATAIP]2.0.CO;2}, author = {Porazinska, D.L. and Bardgett, R.D. and Blaauw, M.B. and Hunt, H.W. and Parsons, A.N. and Seastedt, T.R. and Wall, D.H.} } @article {KNZ00883, title = {Temporal responses of NDVI to precipitation and temperature in the central Great Plains, USA}, journal = {International Journal of Remote Sensing}, volume = {24}, year = {2003}, pages = {2345 -2364}, abstract = {Normalized Difference Vegetation Index (NDVI) is generally recognized as a good indicator of terrestrial vegetation productivity. Understanding climatic influences, in particular precipitation and temperature, on NDVI enables prediction of productivity changes under different climatic scenarios. We examined temporal responses of remotely sensed NDVI to precipitation and temperature during a nine-year period (1989-97) in Kansas. Biweekly (every two weeks) and monthly precipitation data were derived from 410 weather stations and biweekly temperature data were derived from 17 weather stations inside and around the borders of Kansas. Biweekly and monthly climate maps were derived by interpolation. Biweekly growing season (March-October) NDVI values for Kansas were calculated using National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR) NDVI images. Average growing season NDVI values were highly correlated with precipitation received during the current growing season and seven preceding months (15-month duration); biweekly NDVI values were correlated with precipitation received during 2-4 preceding biweekly periods; and response time of NDVI to a major precipitation event was typical 1-2 biweekly periods (2-4 weeks). Temperature was positively correlated with NDVI early and late in the growing season, and there was a weak negative correlation between temperature and NDVI in the mid growing season. Precipitation has the primary influence on NDVI and, by inference, on productivity. The relationship between precipitation and NDVI is strong and predictable when viewed at the appropriate spatial scale.}, keywords = {LTER-KNZ}, doi = {10.1080/01431160210154812}, author = {Wang, J.R. and Price, K.P.} } @article {KNZ00833, title = {Biogeographic variation in nest placement: a case study with conservation implications}, journal = {Diversity and Distributions}, volume = {8}, year = {2002}, pages = {11 -20}, abstract = {Local habitat characteristics are often used to describe a species{\textquoteright} niche despite the fact that habitat use can vary across the geographical range. We sought to quantify variation in habitat preferences by asking how nesting habit varies within and between populations of Bell{\textquoteright}s vireo (Vireo bellii) across its geographical range. Analyses of detailed nest placement data from three localities (Kansas, eastern New Mexico and western New Mexico) showed a general trend towards use of dense vegetation. However, there was substantial variation in nest placement and vegetation at nest sites between localities. Furthermore, a review of nest placement data from the literature shows strong differences in nest heights and species of trees even between populations less than 100 km apart. We evaluate these results in light of conservation and suggest that to be most effective, habitat conservation plans should be based on data collected at the locality where the population of interest occurs.}, keywords = {LTER-KNZ}, doi = {10.1046/j.1366-9516.2001.00126.x}, author = {Parody, J.M. and Parker, T.H.} } @article {KNZ00810, title = {Can uptake length in streams be determined by nutrient addition experiments? Results from an inter-biome comparison study}, journal = {Journal of the North American Benthological Society}, volume = {21}, year = {2002}, pages = {544 -560}, abstract = {Nutrient uptake length is an important parameter for quantifying nutrient cycling in streams. Although nutrient tracer additions are the preferred method for measuring uptake length under ambient nutrient concentrations, short-term nutrient addition experiments have more frequently been used to estimate uptake length in streams. Theoretical analysis of the relationship between uptake length determined by nutrient addition experiments (SW') and uptake length determined by tracer additions (SW) predicted that SW' should be consistently longer than SW, and that the overestimate of uptake length by SW' should be related to the level of nutrient addition above ambient concentrations and the degree of nutrient limitation. To test these predictions, we used data from an interbiome study of NH4+ uptake length in which 15NH4+ tracer and short-term NH4+ addition experiments were performed in 10 streams using a uniform experimental approach. The experimental results largely confirmed the theoretical predictions: SW' was consistently longer than SW and SW':SW ratios were directly related to the level of NH4+ addition and to indicators of N limitation. The experimentally derived SW':SW ratios were used with the theoretical results to infer the N limitation status of each stream. Together, the theoretical and experimental results showed that tracer experiments should be used whenever possible to determine nutrient uptake length in streams. Nutrient addition experiments may be useful for comparing uptake lengths between different streams or different times in the same stream, however, provided that nutrient additions are kept as low as possible and of similar magnitude.}, keywords = {LTER-KNZ, ammonium, nitrogen limitation, nutrient cycling, nutrient spiraling, stream, uptake length}, doi = {10.2307/1468429}, author = {Mulholland, P.J. and Tank, J.L. and Webster, J.R. and W.B. Bowden and W. K. Dodds and Gregory, S.V. and Grimm, N.B. and Hamilton, S.K. and Johnson, S.L. and Marti, E. and W.H. McDowell and Merriam, J. and Meyer, J.L. and Peterson, B.J. and Valett, H.M. and Wollheim, W.M.} } @article {KNZ00806, title = {N uptake as a function of concentration in streams}, journal = {Journal of the North American Benthological Society}, volume = {21}, year = {2002}, pages = {206 -220}, abstract = {Detailed studies of stream N uptake were conducted in a prairie reach and gallery forest reach of Kings Creek on the Konza Prairie Biological Station. Nutrient uptake rates were measured with multiple short-term enrichments of NO3- and NH4+ at constant addition rates in the spring and summer of 1998. NH4+ uptake was also measured with 15N-NH4+ tracer additions and short-term unlabeled NH4+ additions at 12 stream sites across North America. Concurrent addition of a conservative tracer was used to account for dilution in all experiments. NH4+ uptake rate per unit area (Ut) was positively correlated to nutrient concentration across all sites (r2 = 0.41, log{\textendash}log relationship). Relationships between concentration and Ut were used to determine whether the uptake was nonlinear (i.e., kinetic uptake primarily limited by the biotic capacity of microorganisms to accumulate nutrients) or linear (e.g., limited by mass transport into stream biofilms). In all systems, Ut was lower at ambient concentrations than at elevated concentrations. Extrapolation from uptake measured from a series of increasing enrichments could be used to estimate ambient Ut. Linear extrapolation of Ut assuming the relationship passes through the origin and rates measured at 1 elevated nutrient concentration underestimated ambient Ut by \~{}3-fold. Uptake rates were saturated under some but not all conditions of enrichment; in some cases there was no saturation up to 50 μmol/L. The absolute concentration at which Ut was saturated in Kings Creek varied among reaches and nutrients. Uptake rates of NH4+ at ambient concentrations in all streams were higher than would be expected, assuming Ut does not saturate with increasing concentrations. At ambient nutrient concentrations in unpolluted streams, Ut is probably limited to some degree by the kinetic uptake capacity of stream biota. Mass transfer velocity from the water column is generally greater than would be expected given typical diffusion rates, underscoring the importance of advective transport. Given the short-term spikes in nutrient concentrations that can occur in streams (e.g., in response to storm events), Ut may not saturate, even at high concentrations.}, keywords = {LTER-KNZ, advective transport, ammonium, areal uptake, benthos, kinetics, mass transport, Nitrate, nitrogen}, doi = {10.2307/1468410}, author = {W. K. Dodds and L{\'o}pez, A.J. and W.B. Bowden and Gregory, S. and Grimm, N.B. and Hamilton, S.K. and Hershey, A.E. and Marti, E. and W.B. McDowell and Meyer, J.L. and Morrall, D. and Mulholland, P.J. and Peterson, B.J. and Tank, J.L. and van der Hoek, D.C.J. and Webster, J.R. and Wollheim, W.} } @article {KNZ00783, title = {Control of nitrogen export from watersheds by headwater streams}, journal = {Science}, volume = {292}, year = {2001}, pages = {86 -90}, abstract = {A comparative 15N-tracer study of nitrogen dynamics in headwater streams from biomes throughout North America demonstrates that streams exert control over nutrient exports to rivers, lakes, and estuaries. The most rapid uptake and transformation of inorganic nitrogen occurred in the smallest streams. Ammonium entering these streams was removed from the water within a few tens to hundreds of meters. Nitrate was also removed from stream water but traveled a distance 5 to 10 times as long, on average, as ammonium. Despite low ammonium concentration in stream water, nitrification rates were high, indicating that small streams are potentially important sources of atmospheric nitrous oxide. During seasons of high biological activity, the reaches of headwater streams typically export downstream less than half of the input of dissolved inorganic nitrogen from their watersheds.}, keywords = {LTER-KNZ}, doi = {10.1126/science.1056874}, author = {Peterson, B.J. and Wollheim, W.M. and Mulholland, P.J. and Webster, J.R. and Meyer, J.L. and Tank, J.L. and Marti, E. and W.B. Bowden and Valett, H.M. and Hershey, A.E. and W.H. McDowell and W. K. Dodds and Hamilton, S.K. and Gregory, S. and Morrall, D.D.} } @article {KNZ00760, title = {Ecological forecasts: an emerging imperative}, journal = {Science}, volume = {293}, year = {2001}, pages = {657 -660}, abstract = {Planning and decision-making can be improved by access to reliable forecasts of ecosystem state, ecosystem services, and natural capital. Availability of new data sets, together with progress in computation and statistics, will increase our ability to forecast ecosystem change. An agenda that would lead toward a capacity to produce, evaluate, and communicate forecasts of critical ecosystem services requires a process that engages scientists and decision-makers. Interdisciplinary linkages are necessary because of the climate and societal controls on ecosystems, the feedbacks involving social change, and the decision-making relevance of forecasts.}, keywords = {LTER-KNZ}, doi = {10.1126/science.293.5530.657}, author = {Clark, J.S. and Carpenter, S.R. and Barber, M. and Scott. L. Collins and Dobson, A. and Foley, J.A. and Lodge, D.M. and Pascual, M. and Pielke, R and Pizer, W. and Pringle, C. and Reid, W.V. and Rose, K.A. and Sala, O. and Schlesinger, W.H. and Wall, D.H. and Wear, D.} } @inbook {KNZ00792, title = {Fire in Eastern Ecosystems}, booktitle = {Wildland Fire in Ecosystems: Effects of Fire on Flora. Gen. Tech. Rep. RMRS-GTR-42-vol2}, year = {2001}, pages = {53 -96}, publisher = {USDA Forest Service, Rocky Mountain Research Station}, organization = {USDA Forest Service, Rocky Mountain Research Station}, address = {Ogden, UT}, keywords = {LTER-KNZ, fire}, author = {Wade, D. and B. Brock and Brose, P. and Grace, J. and Hoch, G. and Patterson, W.}, editor = {Wade, D. and J. Brown} } @article {KNZ00780, title = {Inter-biome comparison of factors controlling stream metabolism}, journal = {Freshwater Biology}, volume = {46}, year = {2001}, pages = {1503 -1517}, abstract = {1. We studied whole-ecosystem metabolism in eight streams from several biomes in North America to identify controls on the rate of stream metabolism over a large geographic range. The streams studied had climates ranging from tropical to cool-temperate and from humid to arid and were all relatively uninfluenced by human disturbances. 2. Rates of gross primary production (GPP), ecosystem respiration (R) and net ecosystem production (NEP) were determined using the open-system, two-station diurnal oxygen change method. 3. Three general patterns in metabolism were evident among streams: (1) relatively high GPP with positive NEP (i.e. net oxygen production) in early afternoon, (2) moderate primary production with a distinct peak in GPP during daylight but negative NEP at all times and (3) little or no evidence of GPP during daylight and a relatively constant and negative NEP over the entire day. 4. Gross primary production was most strongly correlated with photosynthetically active radiation (PAR). A multiple regression model that included log PAR and stream water soluble reactive phosphorus (SRP) concentration explained 90\% of the variation in log GPP. 5. Ecosystem respiration was significantly correlated with SRP concentration and size of the transient storage zone and, together, these factors explained 73\% of the variation in R. The rate of R was poorly correlated with the rate of GPP. 6. Net ecosystem production was significantly correlated only with PAR, with 53\% of the variation in log NEP explained by log PAR. Only Sycamore Creek, a desert stream in Arizona, had positive NEP (GPP: R > 1), supporting the idea that streams are generally net sinks rather than net sources of organic matter. 7. Our results suggest that light, phosphorus concentration and channel hydraulics are important controls on the rate of ecosystem metabolism in streams over very extensive geographic areas.}, keywords = {LTER-KNZ}, doi = {10.1046/j.1365-2427.2001.00773.x}, author = {Mulholland, P.J. and Fellows, C.S. and Tank, J.L. and Grimm, N.B. and Webster, J.R. and Hamilton, S.K. and Marti, E. and L.R. Ashkenas and W.B. Bowden and W. K. Dodds and W.H. McDowell and Paul, M.J. and Peterson, B.J.} } @article {KNZ0015, title = {Sexual segregation results in differences in content and quality of bison (Bos bison) diets}, journal = {Journal of Mammalogy}, volume = {82}, year = {2001}, pages = {407 -413}, abstract = {We examined diets of bison (Bos bison) bulls, cows, juveniles, and calves to determine differences in quality of diets between groups. Our results showed that bulls had a significantly higher proportion of C4 grasses in their diet than cows, juveniles, or calves. Diets of calves were of higher quality than diets of bulls, cows, or juveniles. Our results provide support for the sexual dimorphism{\textendash}body size hypothesis of sexual segregation in large ungulates.}, keywords = {LTER-KNZ, bison, Bos bison, diet composition, diet quality, sexual segregation}, doi = {http://dx.doi.org/10.1644/1545-1542(2001)082<0407:SSRIDI>2.0.CO;2 }, author = {Post, D.M. and Armbrust, T.A. and Horne, E.A. and Goheen, J.} } @article {KNZ00677, title = {Brown Thrasher Nest Reuse}, journal = {A Time Saving Resource, Protection From Search-strategy Predators, or Cues for Nest-site Selection? The Condor}, volume = {101}, year = {1999}, pages = {859 -862}, abstract = {We examined the potential functions of old nests in a population of Brown Thrashers (Toxostoma rufum) nesting on the Konza Prairie Research Natural Area in northeastern Kansas. We determined whether thrashers reuse nests constructed in previous years, and tested predictions of the hypothesis that old nests function to reduce the risk of nest predation by saturating the cues used by search-strategy predators. We also manipulated old-nest densities to test the hypothesis that old nests are used as indirect cues for nest-site selection. Thrashers were found to reuse nests, albeit at low rates (4\% of nests monitored). We found no significant relationships between the density of old nests and the success of active nests, and experimentally removing nests did not influence nest-site selection. These results suggest that old nests may only benefit thrashers in this population as a resource to reduce the time spent in nest construction.}, keywords = {LTER-KNZ}, doi = {10.2307/1370076}, author = {Cavitt, J.F. and Pearse, A.T. and Miller, T.A.} } @article {KNZ00686, title = {The effects of bison crossings on the macroinvertebrate community in a tallgrass prairie stream}, journal = {American Midland Naturalist}, volume = {141}, year = {1999}, pages = {253 -265}, abstract = {The distribution and diversity of macroinvertebrates in relation to bison crossings was studied for four seasons in a headwater reach of a tallgrass prairie stream. Species richness was significantly higher above crossings only during the fall. Summer samples revealed significantly higher EPT (richness within only Ephemeroptera, Plecoptera and Trichoptera) index values above crossings than at crossings. On average, over 10\% more fine sediment (<0.2 mm) occurred at the crossings than above or below crossings. Densities of two taxa (Hydropsyche spp. and Elmidae) were significantly higher above or below crossings, whereas three taxa (Bezzia/Palpomyia spp., Culicoides sp., and Naididae/Tubificidae) were significantly higher at crossings for at least one season. Overall, this study suggests that impact of bison on benthic communities of headwater streams was spatially limited. Although bison may have less impact upon stream communities than previous studies of cattle impacts have shown, differences in climate and stocking rate could be important factors.}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.1674/0003-0031(1999)141[0253:TEOBCO]2.0.CO;2}, author = {Fritz, K.M. and W. K. Dodds and Pontius, J.} } @article {KNZ00704, title = {Managing Data from Multiple Disciplines, Scales, and Sites to Support Synthesis and Modeling}, journal = {Remote Sensing Environment}, volume = {70}, year = {1999}, pages = {99 -107}, abstract = {The synthesis and modeling of ecological processes at multiple spatial and temporal scales involves bringing together and sharing data from numerous sources. This article describes a data and information system model that facilitates assembling, managing, and sharing diverse data from multiple disciplines, scales, and sites to support integrated ecological studies. Cross-site scientific-domain working groups coordinate the development of data associated with their particular scientific working group, including decisions about data requirements, data to be compiled, data formats, derived data products, and schedules across the sites. The Web-based data and information system consists of nodes for each working group plus a central node that provides data access, project information, data query, and other functionality. The approach incorporates scientists and computer experts in the working groups and provides incentives for individuals to submit documented data to the data and information system.}, keywords = {LTER-KNZ}, doi = {10.1016/S0034-4257(99)00060-7}, author = {Olson, R.J. and J. M. Briggs and Porter, J.H. and Mah, G.R. and Stafford, S.G.} } @article {KNZ00832, title = {Responses of Bell{\textquoteright}s vireos to brood parasitism by the brown-headed cowbird in Kansas}, journal = {Wilson Bulletin}, volume = {111}, year = {1999}, pages = {499 -504}, abstract = {I studied patterns of cowbird parasitism and responses to this parasitism by Bell{\textquoteright}s Vireos (Vireo bellii) in Kansas. Bell{\textquoteright}s Vireos abandoned parasitized nests at a significantly higher rate than unparasitized nests. Lower probability of brood parasitism later in the season may help make abandonment followed by renesting beneficial. Burial of cowbird eggs by vireos was also observed in several cases. I did not detect a strong relationship between nest site vegetation characteristics and the probability of brood parasitism.}, keywords = {LTER-KNZ}, url = {http://www.jstor.org/stable/4164135}, author = {Parker, T.H.} } @inbook {KNZ00623, title = {Data entry}, booktitle = {Data and Information Management in the Ecological Sciences: A Resource Guide}, year = {1998}, publisher = {Long-Term Ecological Research Network Office, University of New Mexico}, organization = {Long-Term Ecological Research Network Office, University of New Mexico}, address = {Albuquerque}, abstract = {One of the many issues that an information management specialist must consider is the need to convert data into a usable electronic format. This frequently means converting data collected in the field, usually on paper, into an electronic form that can then be used in a statistical or graphical package by the researcher. The purpose of this paper is to present guidelines that we have found useful in making this conversion as quick and error-free as possible.}, keywords = {LTER-KNZ}, url = {http://www.ecoinformatics.org/pubs/guide/briggs2.fv2.htm}, author = {J. M. Briggs and Benson, B.J. and Hartman, M. and Ingersoll, R.}, editor = {Michener, W.K. and Porter, J.H. and Stafford, S.G.} } @inbook {KNZ00624, title = {Evolution of the Konza Prairie LTER Information Management System}, booktitle = {Data and Information Management in the Ecological Sciences: A Resource Guide}, year = {1998}, publisher = {Long-Term Ecological Research Network Office, University of New Mexico}, organization = {Long-Term Ecological Research Network Office, University of New Mexico}, address = {Albuquerque}, keywords = {LTER-KNZ}, url = {http://www.ecoinformatics.org/pubs/guide/briggsk.fv2.htm}, author = {J. M. Briggs}, editor = {Michener, W.K. and Porter, J.H. and Stafford, S.G.} } @article {KNZ00628, title = {Hybridization of Mountain Bluebird and Eastern Bluebird in Northeastern Kansas}, journal = {Kansas Ornithological Society}, volume = {49}, year = {1998}, pages = {21 -32}, keywords = {LTER-KNZ}, url = {https://www.researchgate.net/publication/268287117_Hybridization_o_Mountain_Bluebird_and_Eastern_Blubird_In_Northeastern_Kansas}, author = {Cavitt, J.F. and Pearse, A.T. and Rintoul, D.A.} } @article {KNZ00658, title = {Influence of maternal diet and perishability on caching and consumption behavior of juvenile eastern woodrats}, journal = {Journal of Mammalogy}, volume = {79}, year = {1998}, pages = {156 -162}, abstract = {We tested the hypotheses that juvenile eastern woodrats (Neotoma floridana) learned to select appropriate foods to cache by cues from the maternal diet and that the effect of perishability affected caching and consumption behavior of juvenile woodrats. In May 1993, female woodrats were mated and placed on a diet of garlic-flavored chow. Females in group A were fed garlic-flavored chow until offspring were weaned. Females in group B were fed garlic-flavored chow until parturition and then were placed on a diet of standard laboratory chow. All offspring were weaned at 45 days postpartum and maintained on a diet of standard laboratory chow. In October and November 1993, juveniles were tested to determine their preference for caching and consumption of garlic-flavored chow or a novel (mint) flavored chow. Juveniles in group A cached more garlic-flavored chow than juveniles in group B (P = 0.04). There was no difference between groups in the amount of garlic chow consumed (P = 0.5). Naive juveniles preferred to cache dry apple (P = 0.01) but preferred to consume fresh apple (P = 0.01). The outcome of our experiments suggests that maternal diet influences the cache-food selection of naive woodrats. Further, naive juvenile woodrats treat perishable and non-perishable foods in a manner similar to adults suggesting that their response to such foods is not learned.}, keywords = {LTER-KNZ, caching, diet, juveniles, learning, Neotoma floridana, woodrats}, doi = {http://dx.doi.org/10.2307/1382850 }, author = {Post, D.M. and McDonald, M.W. and Reichman, O.J.} } @inbook {KNZ00650, title = {Long-term ecological consequences of varying fire frequency in a humid grassland}, booktitle = {Fire in Ecosystem Management: Shifting The Paradigm From Suppression to Prescription}, year = {1998}, pages = {173 -178}, publisher = {Tall Timbers Research Station}, organization = {Tall Timbers Research Station}, address = {Tallahassee, FL}, keywords = {LTER-KNZ, fire}, author = {Alan K. Knapp and John M. Blair and J. M. Briggs}, editor = {Pruden, T.L. and Brennan, L.A.} } @mastersthesis {KNZ00952, title = {Nest predation and its relationship to nest placement in tallgrass prairie shrub patches}, volume = {MS Thesis}, year = {1997}, pages = {1 -25}, school = {Kansas State University}, type = {M.S. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ}, author = {Parker, T.H.} } @inbook {KNZ00565, title = {Global grassland ecosystem modelling: development and test of ecosystem models for grassland systems}, booktitle = {Global Change: Effects on Coniferous Forests and Grasslands}, year = {1996}, pages = {229 -270}, publisher = {Wiley and Sons}, organization = {Wiley and Sons}, address = {Chichester}, keywords = {LTER-KNZ}, author = {Parton, W.J. and Coughenour, M.B. and Scurlock, J.M.O. and Ojima, D.S. and Gilmanov, T.G. and Scholes, R.J. and Schimel, D.S. and Kirchner, T.B. and Menaut, J.C. and Seastedt, T.R. and Moya, E.G. and Kamnalrut, A. and Kinyamario, J.I. and Hall, D.O.}, editor = {Breymeyer, A.I. and Hall, D.O. and Melillo, J.M. and Agren, G.I.} } @inbook {KNZ00563, title = {Impact of climate and atmospheric carbon dioxide changes on grasslands of the world}, booktitle = {Global Change: Effects on Coniferous Forests and Grasslands}, year = {1996}, pages = {271 -312}, publisher = {Wiley and Sons}, organization = {Wiley and Sons}, address = {Chichester}, keywords = {LTER-KNZ}, author = {Ojima, D.S. and Parton, W.J. and Coughenour, M.B. and Scurlock, J.M.O. and Kirchener, T.B. and Kittel, T.G.F. and Hall, D.O. and Schimel, D.S. and Moya, E.G. and Gilmanov, T.G. and Seastedt, T.R. and Kamnalrut, A. and Kinyamario, J.I. and Long, S.P. and Menaut, J.C. and Sala, O.E. and Scholes, R.J. and van Veen, J.A.}, editor = {Breymeyer, A.I. and Hall, D.O. and Melillo, J.M. and Agren, G.I.} } @proceedings {KNZ00576, title = {New technologies for remote sensing of ecosystem change in rangelands}, journal = {Rangelands in A Sustainable Biosphere}, year = {1996}, pages = {139 -142}, abstract = {The collective area of rangelands, 40-50\% of the global land surface, presents significant logistical challenges for obtaining ecological data for large, heterogeneous areas quickly, cheaply and with a significant level of accuracy. The use of remote sensing for rangeland monitoring and scaling up from plot to region is reviewed. A major challenge in remote sensing applications lies with assessing ecosystem function from spectral measurements of ecosystem structure. New methods which may assist in the identification and tracking of rangeland response to management practices at the regional scale and provide information on vegetation structure at the continental scale are described. On-going attempts to develop a coupled remote sensing rangeland ecosystem modelling approach for monitoring structure and quantifying energy flow and nutrient cycling are described and examples using Konza Prairie, Kansas, USA data are given}, keywords = {LTER-KNZ}, author = {Wessman, C.A. and Schimel, D.S. and S.R. Archer and Bateson, C.A. and Braswell, B.H. and Ojima, D.S. and Parton, W.J. and West, N.E.} } @article {KNZ00513, title = {Antimicrobial activity of dogwood fruits (Cornus drummondii) from winter food caches of the eastern woodrat (Neotoma floridana )}, journal = {Journal of Chemical Ecology}, volume = {21}, year = {1995}, pages = {419 -425}, abstract = {Post-harvest loss of resources to microbial competitors affects a number of species of animals, and many of them have evolved behaviors that reduce the likelihood of such loss. We previously described the inhibition ofBacillus psychrophilus by dogwood fruits (Cornus drummondii), which can comprise a significant portion of the winter food cache of the eastern woodrat (Neotoma floridana). The present study is a further investigation of the ability of dogwood fruits to inhibit growth ofB. psychrophilus. Additionally, we tested the antimicrobial activity of dogwood fruits onEscherichia coli andStaphlococcus aureus. Results of our study indicate that fresh fruits inhibit the growth ofB. psychrophilus andS. aureus but notE. coli. However, fruits taken from woodrat dens after four and six months storage inhibited growth of all three species of bacteria. Further, the strength of inhibition increased over the test period. We suggest the presence of an inhibitor allows woodrats to compete effectively for a valuable and limited food resource.}, keywords = {LTER-KNZ, antimicrobial activity, Bacillus psychrophilus, caching, Cornus drummondii, dogwood fruit, eastern woodrat, Escherichia coli, Neotoma floridana, Staphlococcus aureus}, doi = {10.1007/BF02036739}, author = {Post, D.M. and Urban, J.E.} } @article {KNZ00511, title = {Bison selectivity and grazing responses of little bluestem in tallgrass prairie}, journal = {Journal of Range Management}, volume = {48}, year = {1995}, pages = {26 -31}, abstract = {The perennial bunchgrass little bluestem (Schizachyrium scoparium [Michx.] Nash) was examined in a 5-yr study on tallgrass prairie to determine how fire influences its use by bison and its responses to grazing. On unburned prairie, bison grazed only 5\% of the available little bluestem, selecting it only 30\% as frequently as big bluestem, the dominant co-occurring species. On burned prairie, grazing frequency of little bluestem was over 3-fold greater and equal to that of its dominant neighbor. Grazing frequency of little bluestem was affected by plant size (basal area). On burned sites, plants of intermediate size classes were least abundant (<10\% of total) but were grazed most frequently (>50\%). Small plants were most abundant but were grazed least frequently. Density, tiller numbers, and basal area of little bluestem were significantly greater in annually burned compared to infrequently burned sites but were decreased by > 50\% in grazed compared to ungrazed sites. Grazing shifted the population size distribution toward higher frequencies of smaller individuals (< 50 cm2 basal area), whereas burning increased the frequency of large (> 200 cm2 basal area) individuals. In unburned prairie, little bluestem accumulates a persistent clump of standing dead tillers that appear to serve as a physical deterrent to grazing. Although burning enhances its growth, it also removes its canopy of dead tillers exposing the plant to grazers. The shift in population structure toward a high frequency of smaller (and perhaps less drought- or grazing-tolerant) individuals may contribute to the decline of little bluestem populations under persistent grazing. Thus, plant growth form, population size structure, and fire interact to influence bison grazing patterns and responses of little bluestem to grazing on tallgrass prairie.}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.2307/4002500}, author = {Pfeiffer, K.E. and D.C. Hartnett} } @inbook {KNZ00488, title = {The coyote: an indicator species of environmental change on the great plains}, booktitle = {Our living resources: a report to the nation on the distribution, abundance, and health of U.S. plants, animals, and ecosystems}, year = {1995}, pages = {305 -307}, publisher = {U.S. Department of the Interior, National Biological Service}, organization = {U.S. Department of the Interior, National Biological Service}, address = {Washington, DC}, keywords = {LTER-KNZ}, author = {Gipson, P.S. and Brillhart, D.E.}, editor = {LaRoe, E.T. and Farris, G.S. and Puckett, C.E. and Doran, P.D. and Mac, M.J.} } @inbook {KNZ00477, title = {Influences of earthworms on biogeochemistry}, booktitle = {Earthworm Ecology and Biogeography in North America}, year = {1995}, pages = {125 -156}, publisher = {CRC Press Inc. Lewis Publishers}, organization = {CRC Press Inc. Lewis Publishers}, keywords = {LTER-KNZ}, author = {John M. Blair and Parmelee, R.W. and Lavelle, P.}, editor = {Hendrix, P.F.} } @article {KNZ0014, title = {Regional climatic similarities in the temperate zones of North and South America}, journal = {Journal of Biogeography}, volume = {22}, year = {1995}, pages = {915 -925}, abstract = {

An analysis of the climatic patterns of the temperate zones in North and South America using a global database of monthly precipitation and temperature was performed. Three synthetic variables, identified by a principal component analysis of the monthly data, were used: mean annual precipitation, mean annual temperature and the proportion of the precipitation falling during summer. The spatial gradient of the 3 variables was displayed by constructing a composite colour raster image. A parallelepiped classification algorithm was used to locate areas in both continents that are climatically similar to 5 North American long term ecological research (LTER) sites and to 2 South American LTER sites. The same algorithm was used to identify areas in South America which are climatically similar to some of the major grassland and shrubland types of North America. There was substantial overlap between the climates of North and South America. Most of the climatic patterns found in South America are well represented in North America but there are certain climates in North America that are not found in South America. An example is a climate with relatively low mean annual temperature and high summer precipitation. The climatic signatures of 3 North American LTER sites (Cedar Creek, CPER and Sevilleta) were not found in South America. The climatic signatures of two LTER sites (Konza and Jornada) had some representation in South America. Two South American research sites (Rio Mayo and Las Chilcas) were well represented climatically in North America. The climates of 6 out of 7 selected North American grassland and shrubland types were represented in South America. The northern mixed prairie type was not represented climatically in South America. It is suggested that comparisons of North and South America may provide a powerful test of climatic control over vegetation

}, keywords = {LTER-KNZ, climate}, url = {http://www.jstor.org/stable/2845992}, author = {Paruelo, J.M. and Lauenroth, W.K. and Epstein, H.E. and Burke, I.C. and Aguiar, M.R. and Sala, O.E.} } @phdthesis {KNZ00512, title = {A study of the aquatic humic substances and hydrogeology in a prairie watershed: use of humic material as a tracer of recharge through soils}, volume = {PhD Dissertation}, year = {1995}, pages = {1 -296}, school = {University of Kansas}, type = {Ph.D. Thesis}, address = {Lawrence, KS}, keywords = {LTER-KNZ}, author = {Pomes, M.L.} } @proceedings {KNZ00436, title = {Aboveground biomass in tallgrass prairie: effect of time since last fire}, year = {1994}, pages = {165 -170}, keywords = {LTER-KNZ, tallgrass prairie}, url = {http://images.library.wisc.edu/EcoNatRes/EFacs/NAPC/NAPC13/reference/econatres.napc13.jbriggs.pdf}, author = {J. M. Briggs and Fahnestock, J.T. and Ward, L. and Alan K. Knapp}, editor = {Wickett, R.G. and Lewis, P.D. and Woodliffe, A. and Pratt, P.} } @article {KNZ00467, title = {Importance of photosynthetic pathways, management, and climate on plant production and soil carbon of semihumid temperate grasslands}, journal = {Ecological Applications}, volume = {4}, year = {1994}, pages = {344 -354}, abstract = {A modeling study evaluated the importance of photosynthetic pathways (C3, C4, or both) and management strategies to the foliage productivity and soil carbon characteristics of a semihumid temperate grassland subjected to various combinations of climate change. Model values for plant and soil characteristics were obtained at sites near Manhattan, Kansas, and the Manhattan climate record provided the nominal climatic drivers. Model runs used both actual monthly temperature and precipitation data for a 100{\textemdash}yr interval and average weather conditions generated from this record. Monthly temperatures were increased 2{\textdegree}C, left unchanged, or decreased 2{\textdegree}C; annual precipitation was increased 6 cm, left unchanged, or decreased 6 cm. All possible combinations of temperature and precipitation were then used in 100{\textemdash}yr simulations. Regardless of the specific climate scenario, plant production was lowest for C3 grasses and highest for the mixed C3{\textemdash}C4 community. The nominal seasonal pattern of precipitation favored an active C3 plant community in early to late spring, prior to the emergence of the C4 vegetation. However, the higher growth and water use efficiencies of C4 vegetation during summer contributed to the maximization response of the grasslands containing both C3 and C4 grasses. An analysis of variance of annual average values observed from 100{\textemdash}yr simulations was used to evaluate the relative importance of climate, photosynthetic pathways, and management activities (annually burned, burned every 4 yr, unburned, or lightly grazed) to plant production and soil carbon values. Photosynthetic pathway and precipitation were identified as the most significant single variables affecting foliage production; the interaction between photosynthetic and temperature was the most significant interaction term. Management treatments were by far the most important variables affecting soil carbon values, but 2{\textdegree}C warming did produce substantial soil carbon losses from C3 grasslands. Enhanced carbon fixation by the C4 and C3{\textemdash}C4 plant communities negated the losses of soil carbon caused by enhanced soil respiration at warmer temperatures.}, keywords = {LTER-KNZ}, doi = {10.2307/1941938}, author = {Seastedt, T.R. and Coxwell, C.C. and Ojima, D.S. and Parton, W.J.} } @article {KNZ00464, title = {Long and short-term effects of fire on nitrogen cycling in tallgrass prairie}, journal = {Biogeochemistry}, volume = {24}, year = {1994}, pages = {67 -84}, abstract = {Fires in the tallgrass prairie are frequent and significantly alter nutrient cycling processes. We evaluated the short-term changes in plant production and microbial activity due to fire and the long-term consequences of annual burning on soil organic matter (SOM), plant production, and nutrient cycling using a combination of field, laboratory, and modeling studies. In the short-term, fire in the tallgrass prairie enhances microbial activity, increases both above-and belowground plant production, and increases nitrogen use efficiency (NUE). However, repeated annual burning results in greater inputs of lower quality plant residues causing a significant reduction in soil organic N, lower microbial biomass, lower N availability, and higher C:N ratios in SOM. Changes in amount and quality of below-ground inputs increased N immobilization and resulted in no net increases in N availability with burning. This response occurred rapidly (e.g., within two years) and persisted during 50 years of annual burning. Plant production at a long-term burned site was not adversely affected due to shifts in plant NUE and carbon allocation. Modeling results indicate that the tallgrass ecosystem responds to the combined changes in plant resource allocation and NUE. No single factor dominates the impact of fire on tallgrass plant production.}, keywords = {LTER-KNZ, carbon, fire, immobilization, Mineralization, Nitrogen use efficiency, soil organic matter, tallgrass prairie}, doi = {10.1007/BF02390180}, author = {Ojima, D.S. and Schimel, D.S. and Parton, W.J. and Owensby, C.E.} } @article {KNZ00472, title = {Plant production and the biomass of soil microorganisms in late-successional ecosystems: A continental-scale study}, journal = {Ecology}, volume = {75}, year = {1994}, pages = {2333 -2347}, abstract = {Annual C inputs from plant production in terrestrial ecosystems only meet the maintenance energy requirements of soil microorganisms, allowing for little or no net annual increase in their biomass. Because microbial growth within soil is limited by C availability, we reasoned that plant production should, in part, control the biomass of soil microorganisms. We also reasoned that soil texture should further modify the influence of plant production on soil C availability because fine-textured soils typically support more microbial biomass than coarse-textured soils. To test these ideas, we quantified the relationship between aboveground net primary production (ANPP) and soil microbial biomass in late-successional ecosystems distributed along a continent-wide gradient in North America. We also measured labile pools of C and N within the soil because they represent potential substrate for microbial activity. Ecosystems ranged from a Douglas-fir forest in the western United States to the grasslands of the mid-continent to the hardwood forest in the eastern U.S. Estimates of ANPP obtained from the literature ranged from 82 to 1460 g@?m^-^2@?yr^-^1. Microbial biomass C and N were estimated by the fumigation-incubation technique. Labile soil pools of C and N and first-order rate constants for microbial respiration and net N mineralization were estimated using a long-term (32 wk) laboratory incubation. Regression analyses were used to relate ANPP and soil texture with microbial biomass and labile soil C and N pools. Microbial biomass carbon ranged from 2 g/m^2 in the desert grassland to 134 g/m^2 in the tallgrass prairie; microbial N displayed a similar trend among ecosystems. Labile C pools, derived from a first-order rate equation, ranged from 115 g/m^2 in the desert grassland to 491 g/m^2 in the southern hardwood forest. First-order rate constants for microbial respiration (k) fell within a narrow range of values (0.180 to 0.357 wk^-^1), suggesting that labile C pools were chemically similar among this diverse set of ecosystems. Potential net N mineralization rates over the 32-wk incubation were linear in most ecosystems with first-order responses only in the alpine tundra, tallgrass prairie, and forests. Microbial biomass C displayed a positive, linear relationship with ANPP (r^2 = 0.51), but was not significantly related to soil texture. Labile C also was linearly related to ANPP (r^2 = 0.32) and to soil texture (r^2 = 0.33). Results indicate that microbial biomass and labile organic matter pools change predictably across broad gradients of ANPP, supporting the idea that microbial growth in soil is constrained by C availability.}, keywords = {LTER-KNZ}, doi = {10.2307/1940888}, author = {Zak, D.R. and Tilman, D. and Parameter, R.R. and Fisher, F.M. and C. W. Rice and Vose, J. and Milchunas, D. and Martin, C.W.} } @proceedings {KNZ00456, title = {Water relations and biomass responses to irrigation across a topographic gradient in tallgrass prairie}, year = {1994}, pages = {215 -220}, keywords = {LTER-KNZ, Water relations}, url = {http://images.library.wisc.edu/EcoNatRes/EFacs/NAPC/NAPC13/reference/econatres.napc13.aknapp.pdf}, author = {Alan K. Knapp and Koelliker, J.K. and Fahnestock, J.T. and J. M. Briggs}, editor = {Wickett, R.G. and Lewis, P.D. and Woodliffe, A. and Pratt, P.} } @mastersthesis {KNZ00419, title = {Bison selectivity and grazing response of little bluestem and big bluestem in burned and unburned tallgrass prairie}, volume = {MS Thesis}, year = {1993}, pages = {1 -38}, school = {Kansas State University}, type = {M.S. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ, tallgrass prairie}, author = {Pfeiffer, K.E.} } @article {KNZ00422, title = {Changes in microbial populations from eastern woodrat caches}, journal = {Southwestern Naturalist}, volume = {38}, year = {1993}, pages = {30 -35}, abstract = {Change in microbial populations on three plant foods commonly stored over winter by eastern woodrats (Neotoma floridana) was assessed. It was expected that dogwood fruits (Cornus drummondii) would be affected by microbes to a greater degree than ash seed (Fraxinus pennsylvanica) or redbud seed (Cercis canadensis). Results revealed a change in microbial populations over time but dogwood fruit was no more liable to microbial infestation than seeds. One bacterial species was found in high number on all three food types while three species were found on only two of the three foods. Microbial populations from all three test items increased from November to January but March populations were not different from November populations. It is suggested that climatic factors help to control microbial populations on cache foods.}, keywords = {LTER-KNZ}, doi = {10.2307/3671641}, author = {Post, D.M. and Urban, J.E.} } @article {KNZ00423, title = {Characteristics and significance of the caches of eastern woodrats (Neotoma floridana )}, journal = {Journal of Mammalogy}, volume = {74}, year = {1993}, pages = {688 -692}, abstract = {Caches from eastern woodrat (Neotoma floridana) dens were analyzed for plant-species composition, abundance, and energy content. Body mass and sex of den residents and the den volume were measured to determine correlations with energy content of caches. We found no difference between males and females in den volume or energy content of caches. However, a positive correlation existed between body mass of the cache owner and the amount of energy stored in the cache, such that larger individuals had a disproportionately greater reserve of energy stored in caches than did smaller individuals. The disparity suggests that small individuals are forced to forage outside the den more often than large individuals.}, keywords = {LTER-KNZ, caching, dens, eastern woodrats, energy, food storage, Neotoma floridana}, doi = {10.2307/1382290}, author = {Post, D.M. and Reichman, O.J. and Wooster, D.} } @article {KNZ00421, title = {Detection of differences in nutrient concentrations by eastern woodrats (Neotoma floridana )}, journal = {Journal of Mammalogy}, volume = {74}, year = {1993}, pages = {493 -497}, abstract = {I tested the ability of a small generalist herbivore, the eastern woodrat (Neotoma floridana), to detect differences in concentrations of protein, energy, and lipid available in two nutritionally complex diet items. Within 24 h of exposure to diets, woodrats consumed a greater amount of a standard diet than diets reduced in energy or lipid by 5, 10, or 20\% and a diet reduced by 20\% in protein. However, they did not choose the standard over diets reduced in protein by 5 or 10\%. When consumption was summed over the 9-day duration of choice trials, individuals chose the standard diet over reduced diets. The ability of woodrats to detect relatively small differences in nutrient concentrations should allow them to make efficient use of available foods.}, keywords = {LTER-KNZ}, doi = {10.2307/1382409}, url = {http://www.jstor.org/stable/1382409}, author = {Post, D.M.} } @article {KNZ00418, title = {Observations and modeling of biomass and soil organic matter dynamics for the grassland biome worldwide}, journal = {Global Biogeochemical Cycles}, volume = {7}, year = {1993}, pages = {785 -809}, abstract = {Century is a model of terrestrial biogeochemistry based on relationships between climate, human management (fire, grazing), soil properties, plant productivity, and decomposition. The grassland version of the Century model was tested using observed data from 11 temperate and tropical grasslands around the world. The results show that soil C and N levels can be simulated to within {\textpm}25\% of the observed values (100 and 75\% of the time, respectively) for a diverse set of soils. Peak live biomass and plant production can be simulated within {\textpm} 25\% of the observed values (57 and 60\% of the time, respectively) for burned, fertilized, and irrigated grassland sites where precipitation ranged from 22 to over 150 cm. Live biomass can be generally predicted to within {\textpm}50\% of the observed values (57\% of the time). The model underestimated the live biomass in extremely high plant production years at two of the Russian sites. A comparison of Century model results with statistical models showed that the Century model had slightly higher r2 values than the statistical models. Data and calibrated model results from this study are useful for analysis and description of grassland carbon dynamics, and as a reference point for testing more physiologically based models prediction{\textquoteright}s of net primary production and biomass. Results indicate that prediction of plant and soil organic matter (C and N) dynamics requires knowledge of climate, soil texture, and N inputs.}, keywords = {LTER-KNZ}, doi = {10.1029/93GB02042}, author = {Parton, W.J. and Scurlock, J.M.O. and Ojima, D.S. and Gilmanov, T.G. and Scholes, R.J. and Schimel, D.S. and Kirchner, T. and Menaut, J.C. and Seastedt, T.R. and Moya, E.G. and Kamnalrut, A. and Kinyamario, J.I.} } @mastersthesis {KNZ00420, title = {Persistence of denitrifying enzyme activity and denitrification dynamics in soil}, volume = {MS Thesis}, year = {1993}, pages = {1 -109}, school = {Kansas State University}, type = {M.S. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ}, author = {Picone, L.} } @article {KNZ00374, title = {Change in nutrient content of foods stored by eastern woodrats (Neotoma florida)}, journal = {Journal of Mammalogy}, volume = {73}, year = {1992}, pages = {835 -839}, abstract = {

I determined changes in nutrient content of plants cached by eastern woodrats (Neotoma floridana) after 60 and 120 days storage in a cache environment. The energy content of dogwood fruits (Cornus drummondii) declined significantly due to a decline in lipid content. Concentrations of other nutrients in dogwood fruits remained relatively stable as did nutrient concentrations of green ash seed (Fraxinus pennsylvanica) and redbud seed (Cercis canadensis). However, some small fluctuations in nutrients were observed. The decrease in energy content of cache material may have a significant negative impact on some woodrats that have only a limited amount of food stored in caches.

}, keywords = {LTER-KNZ}, doi = {10.2307/1382204}, author = {Post, D.M.} } @article {KNZ00377, title = {Mass loss and nitrogen dynamics of decaying litter of grasslands: the apparent low nitrogen immobilization potential of root detritus}, journal = {Canadian Journal of Botany}, volume = {70}, year = {1992}, pages = {384 -391}, abstract = {

Litter-bag studies and simulation modeling were used to examine the relationship between mass loss and nitrogen content of decaying prairie foliage and root litter. In contrast with forest studies, grassland roots were low in lignin and nitrogen, decayed more rapidly than foliage, and demonstrated very low nitrogen immobilization potentials. Our findings agree with reports indicating that buried substrates with high C:N ratios do not immobilize substantial amounts of nitrogen-limited environments induce steeper slopes in the mass loss-nitrogen concentration relationship. However, results suggesting rapid nitrogen mineralization contradict our own studies demonstrating reduced inorganic nitrogen availability in soils of frequently burned prairie. Simulation of observed patterns using the CENTURY grassland model indicated that these results could not occur without creating soil organic matter with unrealistically high C:N ratios. Litter-bag studies of buried substrates therefore may provide an incomplete perspective on the mass loss and nitrogen dynamics of buried litter in grassland and agroecosystem soils. key words: Andropogon gerardii, C:N ratio, decomposition, immobilization, mineralization, nitrogen

}, keywords = {LTER-KNZ}, doi = {10.1139/b92-052}, author = {Seastedt, T.R. and Parton, W.J. and Ojima, D.S.} } @phdthesis {KNZ00334, title = {An analysis of factors affecting the caching behavior of the eastern woodrat (Neotoma floridana)}, volume = {PhD Dissertation}, year = {1991}, pages = {1 -91}, school = {Kansas State University}, type = {Ph.D. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ}, author = {Post, D.M.} } @article {KNZ00341, title = {Cryptosporidium and Giardia in surface waters in and around Manhattan, Kansas}, journal = {Transaction of the Kansas Academy of Science}, volume = {94}, year = {1991}, pages = {101 -106}, abstract = {

Cryptosporidium spp. and Giardia spp. are intestinal parasites that can be transmitted through water contaminated by feces. Over a 16 month period, surface waters were examined in Kansas in order to measure local geographic distribution and seasonal fluctuation of oocyst and cyst populations. Cryptosporidium and/or Giardia were found in 86 percent of the locations surveyed

}, keywords = {LTER-KNZ}, doi = {10.2307/3627857}, author = {Todd, C.S. and Phillips, M.S. and Marchin, G.L. and Upton, S.J.} } @article {KNZ00333, title = {Effects of food perishability, distance, and competitors on caching behavior of eastern woodrats}, journal = {Journal of Mammalogy}, volume = {72}, year = {1991}, pages = {513 -517}, keywords = {LTER-KNZ}, doi = {10.2307/1382134}, author = {Post, D.M. and Reichman, O.J.} } @article {KNZ00335, title = {Physiological interactions along resource gradients in a tallgrass prairie}, journal = {Ecology}, volume = {72}, year = {1991}, pages = {672 -684}, abstract = {

Spatial variability in availability of resources that limit photosynthesis (water and N) leads to variation in rates of atmosphere- biosphere exchange. N content and allocation are canopy properties that link ecosystem, physiological, and biophysical processes and that vary in space at scales relevant to atmosphere-biosphere interaction. We studied landscape-scale variation in these and related canopy properties in Kansas Tallgrass Prairie (USA). The tallgrass ecosystem was suited to this investigation because primary production in the prairie is constrained by N availability. This work was designed to aid in interpertation and spatial extrapolation of gas exchange measurements made using aerodynamic techniques as part of FIFE (First ISLSCP Field Experiment), a NASA- supported study. We collected data on spatial disrtibution of biomass, leaf area index (LAI), canopy N mass. N concentration ([N]), and gas exchange along topographic and management gradients. We also measured height distribution of N, light interception, and gas exchange within canopies as a function of position in the landscape. Substantial variation in biomass, LAI, N accumulation, and N allocation occurred over time, with topography, and as a result of previous burning. The verticle gradient of [N] and photosynthetic capacity within canopies were correlated, in space and time, with biomass and canopy light interception. The gradients were steper in high biomass sites than in low biomass sites. In addition, proportional N allocation to the upper layer increased with time (12\% in June, 32\% in August) as biomass increased. As nutrient uptake increased within the tallgrass landscape, biomass increased and light limitation in the lower canopy was induced. As this light limitation increased with increasing biomass, or with accumulation of dead vegetation, allocation of N to the upper canopy increased. Height distribution of photosyntheticd capicity paralleled within-canopy N allocation and light interception. As resource ratios (light, water and nitrogen) varied in the landscape, so did rates of gas exchange. This work suggests that in interactions between light extinction, N allocation, and photosynthesis that have been proposed for monospecific stands apply to the multispecies, but structurally simple, canopy of the tallgrass prairie. Models of plant performance based on evolutionary arguments may provide a powerful basis for spatial extarapolation of atmosphere-ecosystem exchange rates from sites to landscape and larger regions. Key words: atmosphere-ecosystem exchange, FIFE; Konza Prairie Long-Term Ecological Research site; leaf area index; light interception; nitrogen allocation; photosynthetic capacity; photosynthetically active radiation; remote sensing; toposequences

}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.2307/2937207}, author = {Schimel, D.S. and Kittel, T.G.F. and Alan K. Knapp and Seastedt, T.R. and Parton, W.J. and Brown, V.B.} } @article {KNZ00310, title = {Regional analysis of the central Great Plains}, journal = {BioScience}, volume = {41}, year = {1991}, pages = {685 -692}, keywords = {LTER-KNZ}, doi = {http://www.jstor.org/stable/1311763}, author = {Burke, I.C. and Kittel, T.G.F. and Lauenroth, W.K. and Snook, P. and Yonker, C.M. and Parton, W.J.} } @inbook {KNZ00249, title = {Canopy photosynthesis}, booktitle = {Photosynthesis}, year = {1989}, note = {Published}, pages = {227 -241}, publisher = {Alan R. Liss, Inc}, organization = {Alan R. Liss, Inc}, address = {New York, N.Y}, keywords = {LTER-KNZ}, author = {Norman, J.M. and Polley, W.}, editor = {Briggs, W.R.} } @article {KNZ00221, title = {Effects of available P and N:P ratios on non-symbiotic dinitrogen fixation in tallgrass prairie soils}, journal = {Oecologia}, volume = {79}, year = {1989}, pages = {471 -474}, abstract = {

Prescribed burning is a major control over element cycles in Tallgrass prairie (Eastern Kansas, USA). In this paper we report potential effects on fire on non-symbiotic nitrogen fixation. Fire resulted in additions of available P in ash, which may stimulate nitrogen fixation by terrestrial cyanobacteria. Cyanobacterial nitrogenase activity and biomass responded positively to additions of ash or P in laboratory assays using soil. Further assays in soils showed that cyanobacteria responded to changes in available N: available P ratio (aN:P) across a range of concentrations. Nitrogen fixation rate could be related empirically to a N:P via a log-linear relationship. Extrapolation of laboratory results to the field yielded a maximal estimate of 21 kg N ha-1y-1. Results support arguments from the marine and terrestrial literature that P availability is central to regulation of ecosystem N budgets. Key words: Cyanobacteria, fire, acetyline reduction, ash

}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.1007/BF00378663}, author = {Eisele, K.A. and Schimel, D.S. and Kapustka, L.A. and Parton, W.J.} } @proceedings {KNZ00153, title = {Simulating the long-term impact of burning on C, N, and P cycling in a tallgrass prairie}, year = {1988}, pages = {353 -370}, publisher = {Via Nizza}, address = {Roma, Italy}, abstract = {

A model has been developed to simulate the long-term dynamics of soil organic matter and plant production in response to different management practices. The model simulates the flow of C, N, and P in soil-plant systems and deals primarily with the cycling of nutrients in various soil organic matter pools. The model was used to simulate the long- term effects of different fire frequency and timing of the burning on soil organic matter levels, nutrient cycling and plant production. The model results are compared to nutrient cycling data, soil organic matter data and plant production data from a site in Kansas which was established in 1928 to study the impact of annual burning on a tallgrass prairie. The model results compare very favorably with the observed data and show that maximum production is achieved by annual burning in the late spring (April 20). The annual burning also causes the soil organic matter levels and N mineralization potential to decrease. Burning tends to increase the inorganic P levels at the soil surface, which results in increased N fixation

}, keywords = {LTER-KNZ, tallgrass prairie}, author = {Ojima, D.S. and Parton, W.J. and Schimell, D.S. and Owensby, C.E.}, editor = {Giovannozzi-Sermanni, G. and Nannipieri, P.} } @proceedings {KNZ00112, title = {Birds wintering on the Konza Prairie Research Natural Area}, year = {1986}, pages = {91 -94}, publisher = {North Dakota State University: Tri-College Center for Environmental Study}, address = {Fargo, ND,}, abstract = {

Wintering birds were censused along 16 permanent transects (13 in prairie and 3 in gallery forest) that were established within the Konza Prairie Research Natural Area (KPRNA) 10 km south of Manahttan, Kansas. Each transect was censused once in the first two weeks of January during 1982-1984. The prairie transects were either burned or unburned the previous spring and ungranzed by large herbivores for at least six years. Significantly more individuals per km and more species were observed in the gallery forest than in the prairie. The red headed woodpecker (Melanerpes erythrocephalus) was the most abundant species during 1982 and 1984 in the gallery forest, while black-capped chickadee (Parus atricapillus) was the most abundant in 1983. The abundance of red-headed woodpecker was negatively correlated with the abundance of red-bellied woodpecker (Melanerpes carolinus), but not correlated with blue jay (Cyanocitia cristaia) abundance. Red-bellied woodpecker abundance was not correlated with blue jay abundance. American tree sparrow (Spizella arborea) was the most abundant species in the prairie during all three winters

}, keywords = {LTER-KNZ, bird, prairie}, author = {Finck, E.J.}, editor = {Clambey, G.K. and Pemble, R.H.} } @proceedings {KNZ00125, title = {Effects of vegetation, burning and mowing on soil macroarthropods of tallgrass prairie}, year = {1986}, pages = {99 -102}, publisher = {North Dakota State University: Tri-College Center for Environmental Study}, address = {Fargo, ND}, abstract = {

Tallgrass prairie was burned annually, mowed and raked three times yearly, or left undisturbed for two years, and soil anthropods were censused after the first and second years of treatment. Total arthropod densities increased from about 75 individuals/m2 to 132 individuals /m2 and arthropod biomass increased from about 24 kg/ha to 43 kg/ha from November 1981 to March 1983. These increases were associated with increased productivity of prairie vegetation during the initial year of the study. Annual burning resulted in increased biomass of root xylem feeders (cicada nymphs), mowing and raking resulted in increased biomass of root chewing insects (white grubs). Smaller herivores (mostly chrysomelid larvae), predaceous beetle larvae and insect detritivores were most abundant on unburned plots. Overall, arthropod biomass was highest on burned plots; however, densities of arthropods were not significantly different among treatments. Of the arthropods found to be abundant in tallgrass prairie soil, only the white grubs are known to adversely affect plant productivity. Results from this study suggest that drought or land use practices that stress the vegetation will increase densities of these pest insects

}, keywords = {LTER-KNZ, tallgrass prairie}, author = {Seastedt, T.R. and Hayes, D.C. and Petersen, N.J.}, editor = {Clambey, G.K. and Pemble, R.H.} } @proceedings {KNZ00115, title = {Fire effects on tallgrass prairie}, year = {1986}, pages = {138 -142}, publisher = {North Dakota State University: Tri-College Center for Environmental Study}, address = {Fargo, ND}, abstract = {

Fire has been an important natural part of tallgrass prairie ecosystems, started by both lightning and American Indians. Production of vegetation on burned areas can be double that on unburned, unmowed, and ungrazed areas where the old standing dead vegetation is deep. Burning stimulates earlier plant development than on unburned areas. In tallgrass prairie, burning stimulates flowering of warm-season grasses and increases stem density. Late spring burning results in fewer forbs but greater grass production than fall or early spring burning. Up to at least six years, above ground biomass is positively related to the number of years between burning. In Kansas, at least, burning is effective in keeping out exotic plants where the prairie grasses are vigorous. The few studies of fire effects consistently indicate that neither the ash left from burning nor heat form fires affects production. Warming of the increased growth resulting form burning. The increased light for new growth by removal of the old plants seems to be more important

}, keywords = {LTER-KNZ, tallgrass prairie}, author = {Hulbert, L.C.}, editor = {Clambey, G.K. and Pemble, R.H.} } @mastersthesis {KNZ0095, title = {Fruiting strategies of the woody vine Parthenocissus quinquefolia}, volume = {MS Thesis}, year = {1985}, pages = {1 -22}, school = {Kansas State University}, type = {M.S. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ}, url = {http://krex.k-state.edu/dspace/handle/2097/27516}, author = {Pacey, C.} } @article {KNZ0096, title = {Habitat selection by small mammals of the tallgrass prairie: experimental patch choice}, journal = {The Prairie Naturalist}, volume = {17}, year = {1985}, pages = {65 -70}, abstract = {

Small mammals were sampled in 44 experimental burn plots on Konza Prairie Research Natural Area (NPRNA). These plots included burned and unburned upland and burned and unburned lowland tall-grass prairie. Peromyscus maniculatus was most common in burned upland, Reithrodontomys megalotis in unburned lowland, and Sigmodon hispidus in lowland with no response to fire treatment. Experimental patch choice was similar to habitat selection documented by earlier work on large watershed units on KPRNA

}, keywords = {LTER-KNZ, tallgrass prairie}, author = {Peterson, S.K. and Kaufman, G.A. and D.W. Kaufman} } @article {KNZ0086, title = {Peromyscus leucopus in riparian woodlands: use of trees and shrubs}, journal = {Journal of Mammalogy}, volume = {66}, year = {1985}, pages = {139 -143}, abstract = {

Our objective was to describe the use of shrubs and trees by P. leucopus. More specifically, two predictions related to use of verticle habitat structure were examined. The firsst was that use of trees by P. leucopus is directly related to tree size. The second was that use of shrub canopy is directly related to density of branches

}, keywords = {LTER-KNZ}, doi = {10.2307/1380968}, author = {D.W. Kaufman and Peak, M.E. and Kaufman, G.A.} } @article {KNZ0070, title = {Soil structure as influenced by simulated tillage}, journal = {Journal of Soil Science}, volume = {48}, year = {1984}, pages = {879 -884}, abstract = {

Soil is often intensively manipulated by tillage, equipment traffic, and preparation for laboratory analysis. Realizing that manipulated and reconstituted soils have been and are being used in soil structure research, we used surface-soil samples of cultivated and noncultivated Reading silt loam (fine, mixed, mesic, Typic Argindolls) to evaluate the effects of simulated tillage on soil structure and to determine how well the structures of disturbed soils represent the structures of nondisturbed soils of similar composition. Soil cores 86 by 60 mm were formed after the following treatments had been applied: ultrasonically dispersed and freeze- dried, crushed and passed through a 2 mm sieve, and nondisturbed. The soil structural differences were evaluated by soil-water-characteristic curves, saturated-hydraulic conductivities, compression indices, bulk densities, wet and dry aggregate stabilities, and scanning-electron-microscopy. The results show that the soil structures of reconstituted, intensively or even mildly manipulated soils differ considerably from the nondisturbed soils of the same makeup. The greater the disturbance, the greater the differences between the nondisturbed and disturbed soils. The main differences were caused by the destruction of cements and bridges between individual aggregates, which create large, compound-unit (ped) structures. Additional Index Words: dry-aggregate stability, wet-aggregate stability, compression indices, soil-water characteristic, scanning- electron microscopy

}, keywords = {LTER-KNZ, soil, tillage}, author = {Powers, D.H. and Skidmore, E.L.} } @article {KNZ0046, title = {Effect of microhabitat features on habitat use by Peromyscus leucopus}, journal = {The American Midland Naturalist}, volume = {110}, year = {1983}, pages = {177 -185}, abstract = {

Habitat use and selection by the white-footed mouse (Peromyscus leucopus) were examined in riparian woods and associated grassy, shrubbby and limestone outcrop habitats on the Konza Prairie Research Natural Area near Manhattan, Kansas. Analysis of captures on a large, irregular grid (843 stations) demonstrated significant differential use of habitat types by P. leucopus. Selection of habitat types was related to the verticle structure of the vegetation with areas of complex verticle structure (trees with large shrubs, large shrubs without trees or trees with small shrubs) selected over those with less well-developed verticle structure (trees without shrubs, small shrubs without trees or grass). The same basic pattern persisted when microhabitat features in the immediate area of traps were examined. Use of microhabitats associated with rocks, logs, stumps, and fallen trees in the riparian woods revealed greater use of areas with dense cover. The use of microhabitats associated with limestone outcrops confirmed a pattern of greater use of protected than of open areas. Patterns of habitat and microhabitat use were generally consistent with the use of habitat features to avoid predators; however, food distribution was not examined and availability of food in different sites may explain part of the use patterns. Limited observations on habitat selection by Neotoma floridana suggested that competitive interactions between P. leucopus and N. floridana were relatively unimportant in the macro- and microhabitats use patterns of P. leucopus

}, keywords = {LTER-KNZ, habitat}, doi = {10.2307/2425223}, author = {D.W. Kaufman and Peterson, S.K. and Fristik, R. and Kaufman, G.A.} } @proceedings {KNZ0048, title = {The effects of fire, litter and ash on flowering in Andropogon gerardii}, year = {1983}, pages = {21 -24}, publisher = {Department of Biology Western Michigan University}, address = {Kalamazoo, MI}, abstract = {

The objective of this study was to evaluate the relative importance of the direct effects of burning on inflorescence production in Andropogon gerardii. Major treatments used included all possible combinations of presence and absence of fire, litter, and ash. The environmental variables measured included soil moisture, soil temperature, available soil nitrogen, and amount of light at the soil surface. Soil moisture was significantly less on burned plots than on unburned plots. No significant differences in available soil nitrogen were observed. Soil temperatures were significantly higher and light at the soil surface was increased when the organic material was removed. Inflorescence per m2 of canopy cover was significantly increased by the presence of fire. Litter removal and addition of ash did not significantly affect inflorescence production. The results indicate for the first time that the presence of fire itself was a more important environmental cue for increased flowering than removal of litter or addition of ash by burning

}, keywords = {LTER-KNZ, flowering}, author = {Peterson, N.J.}, editor = {Brewer, R.} }