@article {6213, title = {Phytobiome stampede: Bison as potential dispersal agents for the tallgrass prairie microbiome}, journal = {PhytoFrontiers{\texttrademark}}, year = {In Press}, keywords = {LTER-KNZ}, issn = {2690-5442}, doi = {10.1094/PHYTOFR-01-23-0004-SC}, url = {https://apsjournals.apsnet.org/doi/10.1094/PHYTOFR-01-23-0004-SC}, author = {Saleh, Amgad A. and Kraisitudomsook, Nattapol and Frank, Erin and Dendy, Shauna and Leslie, John and Garrett, Karen} } @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 {6288, title = {Product-inhibition feedbacks, not microbial population level tradeoffs or soil pH, regulate decomposition potential under nutrient eutrophication}, journal = {Soil Biology and Biochemistry}, volume = {189}, year = {2024}, pages = {109247}, keywords = {LTER-KNZ}, doi = {10.1016/j.soilbio.2023.109247}, url = {https://www.sciencedirect.com/science/article/abs/pii/S0038071723003097?via\%3Dihub}, author = {Nieland, Matthew A. and Carson, Christine M. and Floyd, Victoria and Zeglin, Lydia H.} } @article {6172, title = {Persistent decadal differences in plant communities assembled under contrasting climate conditions}, journal = {Ecological Applications}, volume = {33}, year = {2023}, pages = {e2823}, keywords = {LTER-KNZ}, doi = {10.1002/eap.2823}, url = {https://onlinelibrary.wiley.com/doi/10.1002/eap.2823}, author = {Eckhoff, Kathryn D. and Scott, Drew A. and Manning, George and S.G. Baer} } @mastersthesis {6275, title = {Prairie plant communities and their associated phyllosphere fungal communities change across the steep precipitation gradient in Kansas USA, though individual plant species{\textquoteright} phyllosphere communities may not}, volume = {MS Thesis}, year = {2023}, school = {Kansas State University}, type = {M.S. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ}, url = {https://krex.k-state.edu/bitstream/handle/2097/43453/HannahDea2023.pdf?sequence=12}, author = {Dea, H.} } @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 {6070, title = {Prairie stream metabolism recovery varies based on antecedent hydrology across a stream network after a bank-full flood}, journal = {Limnology and Oceanography}, volume = {67}, year = {2022}, pages = {1986-1999}, keywords = {LTER-KNZ}, doi = {10.1002/lno.12182}, url = {https://onlinelibrary.wiley.com/doi/10.1002/lno.12182}, author = {Ruffing, Claire M. and Veach, A.M. and Schechner, Anne and R{\"u}egg, Janine and Trentman, Matt T. and W. K. Dodds} } @article {6023, title = {Precipitation effects on nematode diversity and carbon footprint across grasslands}, journal = {Global Change Biology}, volume = {28}, year = {2022}, pages = {2124-2132}, keywords = {LTER-KNZ}, doi = {10.1111/gcb.16055}, url = {https://onlinelibrary.wiley.com/doi/10.1111/gcb.16055}, author = {Franco, Andr{\'e} L.C. and Guan, Pingting and Cui, Shuyan and Tomasel, Cecilia M. and Gherardi, Laureano A. and Sala, O.E. and Wall, Diana H.} } @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 {6024, title = {Predation, parasitism, and drought counteract the benefits of patch-burn grazing for the reproductive success of grassland songbirds}, journal = {Ornithological Applications}, volume = {124}, year = {2022}, pages = {1{\textendash}22}, keywords = {LTER-KNZ}, doi = {10.1093/ornithapp/duab066}, url = {https://academic.oup.com/condor/advance-article/doi/10.1093/ornithapp/duab066/6506482}, author = {Verheijen, B.H.F. and Erickson, Amy N and W.A. Boyle and Leveritte, Kiana S and Sojka, Jennifer L and Spahr, Lauren A and Williams, Emily J and Winnicki, Sarah K and Sandercock, B.K.} } @article {5981, title = {Patterns and trends of organic matter processing and transport: Insights from the US Long-Term Ecological Research network}, journal = {Climate Change Ecology}, volume = {2}, year = {2021}, pages = {100025}, keywords = {LTER-KNZ}, doi = {10.1016/j.ecochg.2021.100025}, url = {https://linkinghub.elsevier.com/retrieve/pii/S2666900521000253}, author = {Harms, Tamara K. and Groffman, Peter M. and Aluwihare, Lihini and Craft, Chris and Wieder, William R and Hobbie, Sarah E. and S.G. Baer and J. M. Blair and Frey, Serita and Remucal, Christina K. and Rudgers, Jennifer A. and S L Collins} } @article {6113, title = {Plant diversity and litter accumulation mediate the loss of foliar endophyte fungal richness following nutrient addition}, journal = {Ecology}, volume = {102}, year = {2021}, pages = {e03210}, keywords = {LTER-KNZ}, doi = {10.1002/ecy.3210}, url = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1002/ecy.3210}, author = {Henning, Jeremiah A. and Kinkel, Linda and May, Georgiana and Lumibao, Candice Y. and Seabloom, Eric W. and Borer, Elizabeth T.} } @article {5991, title = {Plant legacies and soil microbial community dynamics control soil respiration}, journal = {Soil Biology and Biochemistry}, volume = {160}, year = {2021}, pages = {108350}, keywords = {LTER-KNZ}, doi = {10.1016/j.soilbio.2021.108350}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0038071721002236}, author = {Connell, R. Kent and L.H. Zeglin and J. M. Blair} } @article {6002, title = {Precipitation manipulation and terrestrial carbon cycling: The roles of treatment magnitude, experimental duration and local climate}, journal = {Global Ecology and Biogeography}, volume = {30}, year = {2021}, pages = {1909 - 1921}, keywords = {LTER-KNZ}, doi = {10.1111/geb.13356}, url = {https://onlinelibrary.wiley.com/doi/10.1111/geb.13356?af=R}, author = {Wang, Jinsong and Tian, Dashuan and Alan K. Knapp and Chen, Han Y. H. and Luo, Yiqi and Li, Zhaolei and Hou, Enqing and Huang, Xinzhao and Jiang, Lifen and Niu, Shuli}, editor = {Michaletz, Sean} } @article {6001, title = {Precipitation{\textendash}productivity relationships and the duration of precipitation anomalies: An underappreciated dimension of climate change}, journal = {Global Change Biology}, volume = {27}, year = {2021}, pages = {1127 - 1140}, keywords = {LTER-KNZ}, issn = {1354-1013}, doi = {10.1111/gcb.15480}, url = {https://onlinelibrary.wiley.com/doi/10.1111/gcb.15480}, author = {Felton, A.J. and Alan K. Knapp and M. D. Smith} } @article {5969, title = {Is a prescribed fire sufficient to slow the spread of woody plants in an infrequently burned grassland? A case study in tallgrass prairie}, journal = {Rangeland Ecology \& Management}, volume = {78}, year = {2021}, pages = {79 - 89}, abstract = {

In many mesic grasslands, such as the central Great Plains in North America, frequent fire is a key regulator of ecological processes. Long periods of infrequent fire facilitate the conversion of herbaceous-dominated grassland to woody-dominated shrubland or woodland. At the Konza Prairie Biological Station in northeast Kansas, one infrequently burned portion of the landscape has undergone transformation from grassland to woodland after nearly 30 yr without fire. In Spring 2017, a prescribed burn was implemented to assess fire effectiveness on woody plant mortality. A postfire census of 3 000+ individual woody plants identified the distribution of species by size (height), topographic position, and slope on the landscape. Mortality and canopy fire damage were calculated for each individual. In lowland locations with near-continuous shrub cover (30.7\% of the landscape), woody plants were unaffected by fire. However, in upland and slope locations, where shrubs and trees were sparser, survival probability varied by topographic position and species. In these locations 68\% of all woody individuals experienced 90\% or greater fire damage to the canopy, with 56\% of these individuals exhibiting new canopy regrowth within 2 mo after the fire. The two most abundant woody shrubs, Cornus drummondii and Rhus aromatica, showed high survival at all height classes and landscape positions. The two abundant tree species, Gleditsia triacanthos and Juniperus virginiana, showed increased survival probability with tree height that varied by landscape position. Survival of J. virginiana also varied according to proximity and size of neighboring clonal shrubs, providing a mechanism for persistence of this fire-sensitive tree species even at small height classes. The probability survival curves developed here are useful for managers assessing when to prescribe fire to maximize mortality for J. virginiana and provide insight relevant for broader ecological understanding of woody encroachment within grasslands throughout the world.

}, keywords = {LTER-KNZ}, doi = {10.1016/j.rama.2021.05.007}, url = {https://linkinghub.elsevier.com/retrieve/pii/S1550742421000609}, author = {Nippert, J.B. and Telleria, Lizeth and Blackmore, Pamela and Taylor, Jeffrey H. and O{\textquoteright}Connor, Rory C.} } @article {KNZ002006, title = {Plant phylogenetic history explains in-stream decomposition at a global scale}, journal = {Journal of Ecology}, volume = {108}, year = {2020}, pages = {17-35}, abstract = {

\ \ \  1. Evolutionary history and adaptation to climate shape plant traits. Some include leaf traits that influence litter quality. Thus, evolutionary history should affect litter decomposition, a crucial ecosystem process. In addition, litter decomposition is directly influenced by climate. We consequently expect plant phylogeny, adaptation and climate to jointly influence litter decomposition. These effects and their interactions have yet to be untangled at a global scale.
\ \ \  2. Here we present an analysis of variation in litter decomposition rates in rivers and streams across 285 published studies for 239 species (from ferns to angiosperms) distributed at 494 locations world-wide. We estimated the relative contributions of climatic conditions and phylogenetic heritage on litter decomposition rates, partitioning phylogenetic from climatic effects at the site and species levels using phylogenetic eigenvector analysis and phylogenetic linear mixed models. In addition, we modelled transitions in decomposition rates under a suite of multiple adaptive-regime Ornstein\–Uhlenbeck models to test the hypothesis that natural selection has shaped clade-level litter decomposition rates.
\ \ \  3. Leaf litter decomposition rate exhibited a significant phylogenetic signal. Modelling decomposition rate as a function of location, climatic niche and phylogeny consistently recovered phylogeny alone as one of the top models in species-level analyses. Since many previous studies have focused on the same species across many locations, we also conducted analyses at the species \× site level. Both phylogenetic and climatic factors were favoured in models of this analysis, but the single most important predictor for angiosperms and for all taxa analysed together was phylogeny alone.
\ \ \  4. Synthesis. For plant species distributed globally at nearly 500 locations we found that plant phylogenetic history is a critically important predictor of litter decomposition rate in rivers and streams, explaining more of the variance in decomposition than site or climatic regime. Thus, our study demonstrates the influence of evolutionary history on suites of plant traits that shape a key ecosystem process.

}, keywords = {LTER-KNZ}, issn = {0022-0477}, doi = {10.1111/1365-2745.13262}, url = {https://besjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1365-2745.13262}, author = {LeRoy, Carri J. and Hipp, Andrew L. and Lueders, Kate and Follstad Shah, Jennifer J. and Kominoski, John S. and Ard{\'o}n, Marcelo and W. K. Dodds and Gessner, Mark O. and Griffiths, Natalie A. and Lecerf, Antoine and Manning, David W. P. and Sinsabaugh, Robert L. and Webster, Jack R.}, editor = {Wardle, David} } @article {KNZ002007, title = {Plant{\textendash}microbial interactions facilitate grassland species coexistence at the community level}, journal = {Oikos}, volume = {129}, year = {2020}, pages = {533-543}, abstract = {

Interspecific competition and plant\–soil feedbacks are powerful drivers of plant community structure. However, across a range of edaphic conditions the interactive effects of these drivers on complex plant communities remain unclear. For example, plant\–soil feedback studies focus on soil trained by a single plant species. We developed a method to assess effects of plant\–microbial interactions (PMI) on a complex plant community. We established mesocosms with 13 grassland species, grown individually or together, in overgrazed or restored soil, with or without soil microbial inoculum collected from a productive and diverse native grassland. We assessed biomass production as influenced by edaphic conditions, interspecific competition and PMI. Furthermore, we assessed potential influences of interspecific competition and edaphic conditions on strength and direction of PMI. Our results indicate PMI drives negative growth responses for graminoids while forbs experience positive growth responses. Generally, interspecific competition did not alter the magnitude or direction of PMI-mediated growth responses. Edaphic conditions altered the influence of soil microbial communities on individual plant growth while PMI facilitated plant evenness. In plant community mesocosms, PMI-associated benefits were observed in overgrazed soil. However, interspecific competition overwhelmed plant growth benefits associated with soil microbial communities when plant communities were grown in restored soil. In mesocosms containing dominant grass species, interspecific competition had negative effects on species coexistence, but both positive and negative PMI partially counterbalanced this influence on plant species evenness. Understanding these mechanisms may improve our capacity to manage diverse and productive grasslands by enabling prediction of plant community composition following disturbance and subsequent restoration.

}, keywords = {LTER-KNZ}, issn = {0030-1299}, doi = {10.1111/oik.06609}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/oik.06609}, author = {Li, Jiahuan and Xie, Shu and G.T. Wilson and Cobb, Adam B. and Tang, Shiming and Guo, Lizhu and Wang, Kun and Deng, Bo} } @article {KNZ002054, title = {Populations of small mammals, tallgrass prairie and prescribed fire: A fire-reversal experiment}, journal = {Transactions of the Kansas Academy of Science}, volume = {123}, year = {2020}, pages = {1}, keywords = {LTER-KNZ}, doi = {10.1660/062.123.0101}, url = {https://bioone.org/journals/transactions-of-the-kansas-academy-of-science/volume-123/issue-1-2/062.123.0101/Populations-of-Small-Mammals-Tallgrass-Prairie-and-Prescribed-Fire/10.1660/062.123.0101.full}, author = {Kaufman, Donald W. and Kaufman, Glennis A. and Reed, Aaron W. and Kaufman, Dawn M. and Rehmeier, Ryan L.} } @article {KNZ002008, title = {Precipitation amount and event size interact to reduce ecosystem functioning during dry years in a mesic grassland}, journal = {Global Change Biology}, volume = {26}, year = {2020}, pages = {658-668}, abstract = {

Ongoing intensification of the hydrological cycle is altering rainfall regimes by increasing the frequency of extreme wet and dry years and the size of individual rainfall events. Despite long-standing recognition of the importance of precipitation amount and variability for most terrestrial ecosystem processes, we lack understanding of their interactive effects on ecosystem functioning. We quantified this interaction in native grassland by experimentally eliminating temporal variability in growing season rainfall over a wide range of precipitation amounts, from extreme wet to dry conditions. We contrasted the rain use efficiency (RUE) of above-ground net primary productivity (ANPP) under conditions of experimentally reduced versus naturally high rainfall variability using a 32-year precipitation\–ANPP dataset from the same site as our experiment. We found that increased growing season rainfall variability can reduce RUE and thus ecosystem functioning by as much as 42\% during dry years, but that such impacts weaken as years become wetter. During low precipitation years, RUE is lowest when rainfall event sizes are relatively large, and when a larger proportion of total rainfall is derived from large events. Thus, a shift towards precipitation regimes dominated by fewer but larger rainfall events, already documented over much of the globe, can be expected to reduce the functioning of mesic ecosystems primarily during drought, when ecosystem processes are already compromised by low water availability.

}, keywords = {LTER-KNZ}, issn = {1354-1013}, doi = {10.1111/gcb.14789}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.14789}, author = {Felton, Andrew J. and Slette, Ingrid J. and M.D. Smith and Alan K. Knapp} } @article {KNZ001979, title = {Periodical cicada emergence resource pulse tracks forest expansion in a tallgrass prairie landscape}, journal = {Ecosphere}, volume = {10}, year = {2019}, pages = {e02779. 10.1002/ecs2.2779}, abstract = {

Understanding factors that influence resource pulses is an important aspect of ecosystem ecology. We quantified below- to aboveground energy and nutrient fluxes during the 2015 periodical cicada emergence from forest habitats in a tallgrass prairie matrix and compared results to our prior studies of the 1998 emergence in the same watershed. We estimated 35.2 million cicadas emerged across 159 ha in 2015, almost 2\× more than the 19.6 million across 98 ha in 1998. The 2015 emergence resulted in below- to aboveground fluxes of 9.4 metric tons of ash-free dry mass and 1.12 metric tons of N, both ~2\× greater than 1998. This corresponds to 59 kg C/ha and 7 kg N/ha in and adjacent to forested areas in 2015. Increased emergence in 2015 was a result of spatial expansion of cicadas, not higher densities. Periodical cicadas are expanding with forest habitats in this region. Cicadas expand into and oviposit in ~40\% of available forest habitat during each emergence. Accordingly, we predict the 2032 emergence will span ~245 ha. Our study demonstrates how human alterations to a landscape, in this case forest expansion linked to fire suppression and reduced grazing, can alter the magnitude and extent of a resource pulse.

}, keywords = {LTER-KNZ}, doi = {10.1002/ecs2.2019.10.issue-710.1002/ecs2.2779}, url = {https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecs2.2779}, author = {M.R. Whiles and Snyder, Bruce A. and B. Brock and S. Bonjour and Callaham, Mac A. and Meyer, Clinton K. and Bell, Alex} } @article {KNZ001980, title = {Phenology-adjusted dynamic curve number for improved hydrologic modeling}, journal = {Journal of Environmental Management}, volume = {235}, year = {2019}, pages = {403 - 413}, abstract = {

The Soil Conservation Service Curve Number (SCS-CN, or CN) is a widely used method to estimate runoff from rainfall events. It has been adapted to many parts of the world with different land uses, land cover types, and climatic conditions and successfully applied to situations ranging from simple runoff calculations and land use change assessment to comprehensive hydrologic/water quality simulations. However, the CN method lacks the ability to incorporate seasonal variations in vegetated surface conditions, and unnoticed landuse/landcover (LULC) change that shape infiltration and storm runoff. Plant phenology is a main determinant of changes in hydrologic processes and water balances across seasons through its influence on surface roughness and evapotranspiration. This study used regression analysis to develop a dynamic CN (CNNDVI) based on seasonal variations in the remotely-sensed Normalized Difference Vegetation Index (NDVI) to monitor intra-annual plant phenological development. A time series of 16-day MODIS NDVI (MOD13Q1 Collection 5) images were used to monitor vegetation development and provide NDVI data necessary for CNNDVI model calibration and validation. Twelve years of rainfall and runoff data (2001\–2012) from four small watersheds located in the Konza Prairie Biological Station, Kansas were used to develop, calibrate, and validate the method. Results showed CNNDVI performed significantly better in predicting runoff with calibrated CNNDVI runoff increasing by approximately 0.74 for every unit increase in observed runoff compared to 0.46 for SCS-CN runoff and was more highly correlated to observed runoff (r = 0.78 vs. r = 0.38). In addition, CNNDVI runoff had better NSE (0.53) and PBIAS (4.22) compared to the SCS-CN runoff (\−0.87 and \−94.86 respectively). In the validated model, CNNDVI runoff increased by approximately 0.96 for every unit of observed runoff, while SCS-CN runoff increased by 0.49. Validated runoff was also better correlated to observed runoff than SCS-CN runoff (r=0.52 vs. r=0.33). These findings suggest that the CNNDVI can yield improved estimates of surface runoff from precipitation events, leading to more informed water and land management decisions.

}, keywords = {LTER-KNZ}, doi = {10.1016/j.jenvman.2018.12.115}, url = {https://www.sciencedirect.com/science/article/pii/S0301479718315433}, author = {Muche, Muluken E. and Hutchinson, Stacy L. and Hutchinson, J.M. Shawn and Johnston, John M.} } @article {KNZ001981, title = {Phosphorus and mowing improve native alfalfa establishment, facilitating restoration of grassland productivity and diversity}, journal = {Land Degradation \& Development}, volume = {30}, year = {2019}, pages = {647 - 657}, keywords = {LTER-KNZ}, doi = {10.1002/ldr.v30.610.1002/ldr.3251}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/ldr.3251}, author = {Zhou, Jiqiong and G.T. Wilson and Cobb, Adam B. and Yang, Gaowen and Zhang, Yingjun} } @article {KNZ001982, title = {A practical guide for combining data to model species distributions}, journal = {Ecology}, volume = {81}, year = {2019}, pages = {e02710}, abstract = {

Understanding and accurately modeling species distributions lies at the heart of many problems in ecology, evolution, and conservation. Multiple sources of data are increasingly available for modeling species distributions, such as data from citizen science programs, atlases, museums, and planned surveys. Yet reliably combining data sources can be challenging because data sources can vary considerably in their design, gradients covered, and potential sampling biases. We review, synthesize, and illustrate recent developments in combining multiple sources of data for species distribution modeling. We identify five ways in which multiple sources of data are typically combined for modeling species distributions. These approaches vary in their ability to accommodate sampling design, bias, and uncertainty when quantifying environmental relationships in species distribution models. Many of the challenges for combining data are solved through the prudent use of integrated species distribution models: models that simultaneously combine different data sources on species locations to quantify environmental relationships for explaining species distribution. We illustrate these approaches using planned survey data on 24 species of birds coupled with opportunistically collected eBird data in the southeastern United States. This example illustrates some of the benefits of data integration, such as increased precision in environmental relationships, greater predictive accuracy, and accounting for sample bias. Yet it also illustrates challenges of combining data sources with vastly different sampling methodologies and amounts of data. We provide one solution to this challenge through the use of weighted joint likelihoods. Weighted joint likelihoods provide a means to emphasize data sources based on different criteria (e.g., sample size), and we find that weighting improves predictions for all species considered. We conclude by providing practical guidance on combining multiple sources of data for modeling species distributions.

}, keywords = {LTER-KNZ}, doi = {10.1002/ecy.2710}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/ecy.2710}, author = {Fletcher,R.J. and Hefley, T.J. and Robertson, Ellen P. and Zuckerberg, Benjamin and McCleery, Robert A. and Dorazio, Robert M.} } @article {KNZ001822, title = {Partitioning assimilatory nitrogen uptake in streams: an analysis of stable isotope tracer additions across continents}, journal = {Ecological Monographs}, volume = {88}, year = {2018}, pages = {138}, chapter = {120}, abstract = {

Headwater streams remove, transform, and store inorganic nitrogen (N) delivered from surrounding watersheds, but excessive N inputs from human activity can saturate removal capacity. Most research has focused on quantifying N removal from the water column over short periods and in individual reaches, and these ecosystem-scale measurements suggest that assimilatory N uptake accounts for most N removal. However, cross-system comparisons addressing the relative role of particular biota responsible for incorporating inorganic N into biomass are lacking. Here we assess the importance of different primary uptake compartments on reach-scale ammonium (NH4+-N) uptake and storage across a wide range of streams varying in abundance of biota and local environmental factors. We analyzed data from 17\ 15N-NH4+tracer addition experiments globally, and found that assimilatory N uptake by autotrophic compartments (i.e., epilithic biofilm, filamentous algae, bryophytes/macrophytes) was higher but more variable than for heterotrophic microorganisms colonizing detrital organic matter (i.e., leaves, small wood, and fine particles). Autotrophic compartments played a disproportionate role in N uptake relative to their biomass, although uptake rates were similar when we rescaled heterotrophic assimilatory N uptake associated only with live microbial biomass. Assimilatory NH4+-N uptake, either estimated as removal from the water column or from the sum uptake of all individual compartments, was four times higher in open- than in closed-canopy streams. Using Bayesian Model Averaging, we found that canopy cover and gross primary production (GPP) controlled autotrophic assimilatory N uptake while ecosystem respiration (ER) was more important for the heterotrophic contribution. The ratio of autotrophic to heterotrophic N storage was positively correlated with metabolism (GPP: ER), which was also higher in open- than in closed-canopy streams. Our analysis shows riparian canopy cover influences the relative abundance of different biotic uptake compartments and thus GPP:ER. As such, the simple categorical variable of canopy cover explained differences in assimilatory N uptake among streams at the reach scale, as well as the relative roles of autotrophs and heterotrophs in N storage. Finally, this synthesis links cumulative N uptake by stream biota to reach-scale N demand and provides a mechanistic and predictive framework for estimating and modeling N cycling in other streams.

}, keywords = {LTER-KNZ}, doi = {10.1002/ecm.1280}, url = {https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/ecm.1280}, author = {Tank, J.L. and Marti, E. and Riis, T. and von Schiller, D. and Reisinger, A.J. and W. K. Dodds and M.R. Whiles and L.R. Ashkenas and W.B. Bowden and S. M. Collins and Crenshaw, C.L. and Crowl, T.A. and Griffiths, N.A. and Grimm, N.B. and Hamilton, S.K. and Johnson, S.L. and McDowell, W.H. and Norman, B.M. and Rosi, E.J. and Simon, K.S. and Thomas, S.A. and Webster, J.R.} } @article {KNZ001817, title = {Patterns and correlates of within-season breeding dispersal: a common strategy in a declining grassland songbird}, journal = {The Auk: Ornithological Advances}, volume = {135}, year = {2018}, pages = {1-14}, abstract = {

Dispersal is a ubiquitous behavior with important consequences for gene flow, demography, and conservation. Some birds engage in between-year breeding dispersal, but the factors shaping variation in this behavior are not well understood. In mid-continental grasslands, preliminary evidence suggested that Grasshopper Sparrows (Ammodramus savannarum) dispersed not only between seasons, but also within breeding seasons\—an apparently uncommon avian behavior. We studied a population of Grasshopper Sparrows breeding in northeastern Kansas, USA, to document the spatial and temporal patterns of within-season breeding dispersal in an experimentally managed tallgrass prairie from 2013 to 2015. We combined color-band resighting, territory mapping, and radio telemetry to quantify changes in territory density, turnover of territorial males, and dispersal distances. Density of Grasshopper Sparrows varied seasonally in management-specific ways, simultaneously increasing and decreasing in watersheds that differed in management regime. Turnover was unexpectedly high, with over half of territorial males being replaced each month. We documented over a third of males dispersing up to \∼9 km between breeding attempts. Our study provides the first comprehensive description of the patterns of within-season breeding dispersal in a grassland songbird. Our results reveal the remarkable prevalence of within-season movement in this system and the relatively large distances over which birds disperse. Such mobility has important implications for survey design and habitat management, as birds select habitat at much larger spatial scales than is generally appreciated. These results also provide foundational information for tests of alternative hypotheses explaining the ecological and evolutionary basis for such movements.

}, keywords = {LTER-KNZ, Grasslands, inter-patch movement, intra-season movement, Konza Prairie, LTER, mid-season habitat shifts, territory switching}, doi = {10.1642/AUK-17-69.1}, url = {http://www.bioone.org/doi/pdf/10.1642/AUK-17-69.1}, author = {Williams, E.J. and W. A. Boyle} } @article {KNZ001926, title = {Physiological and anatomical trait variability of dominant C4 grasses}, journal = {Acta Oecologica}, volume = {93}, year = {2018}, pages = {14 - 20}, abstract = {

Climate variability is a key driver of physiological responses in common grass species in grasslands of North America. Differences in microanatomical traits among coexisting species may influence physiological responses to climate variability over large geographic scales. The goal of this research was to determine leaf-level physiological and microanatomical trait variability among four dominant C4 grass species across a natural precipitation gradient. Physiological traits were observed to vary significantly across the gradient with greater variability than microanatomical traits. Microanatomical traits were shown to predict physiological responses in A. gerardii and P. virgatum, but the nature of the relationships varied between species. These results illustrate that microanatomical and physiological traits vary across a precipitation gradient, there are clear linkages between microanatomy and physiology in grass species, and this evidence underscores the need for further investigation using phylogenetically diverse assemblages.

}, keywords = {LTER-KNZ}, doi = {10.1016/j.actao.2018.10.007}, url = {https://linkinghub.elsevier.com/retrieve/pii/S1146609X17304587}, author = {Bachle, Seton. and Jesse B. Nippert} } @article {KNZ001900, title = {Plant functional group influences arbuscular mycorrhizal fungal abundance and hyphal contribution to soil CO2 efflux in temperate grasslands}, journal = {Plant and Soil}, volume = {432}, year = {2018}, pages = {157-170}, abstract = {

Background and aims: Arbuscular mycorrhizal (AM) fungi are abundant in grassland ecosystem. We assessed AM hyphal contributions to soil CO2 efflux across plant functional groups to better quantify AM fungal influences on soil carbon dynamics.


Methods: We conducted a field experiment using in-growth mesocosms to partition soil CO2 efflux from roots, AM hyphae, and free-living soil microbes associated with C3 grasses, C4 grasses, forbs, and diverse plant communities from May to August in 2017.


Results: AM hyphae contributed \<10\% to total soil respiration in forb communities and diverse plant communities but accounted for as much as 32\% in C3 grasses. Plant functional groups differed in hyphal production efficiencies (the ratio of AM hyphal length to aboveground biomass), with the lowest in C3 grasses (0.47?\±?0.15 m g-1) and the greatest in forbs (3.27?\±?0.55 m g-1). Mowing reduced hyphal production efficiency of C4 grasses and forbs but did not affect total soil respiration. AM hyphal and microbial respiration peaked at the middle of the growing season, however there was no significant seasonal variation in root respiration.


Conclusion: AM hyphal respiration is an important pathway of carbon flux from plants to atmosphere. Shifts in plant community composition can influence soil carbon processes by regulating hyphal production and respiration.

}, keywords = {LTER-KNZ}, doi = {10.1007/s11104-018-3789-0}, url = {http://link.springer.com/10.1007/s11104-018-3789-0}, author = {Gui, Weiyang and Ren, Haiyan and Liu, Nan and Zhang, Yingjun and Cobb, Adam B. and G.T. Wilson and Sun, Xiao and Hu, Jian and Xiao, Yan and Zhang, Fengge and Yang, Gaowen} } @mastersthesis {KNZ001859, title = {Partitioning the CO2 net flux into assimilation and respiration components, and estimating water use efficiency in a grassland ecosystem}, volume = {MS Thesis}, year = {2017}, school = {Federal University of Vicosa}, type = {M.S. Thesis}, address = {Vi{\c c}osa, Brazil}, keywords = {LTER-KNZ}, author = {Alves, J.D.N.} } @article {KNZ001854, title = {Phenotypic distribution models corroborate species distribution models: A shift in the role and prevalence of a dominant prairie grass in response to climate change}, journal = {Global Change Biology}, volume = {23}, year = {2017}, pages = {4365{\textendash}4375}, abstract = {

Phenotypic distribution within species can vary widely across environmental gradients but forecasts of species\’ responses to environmental change often assume species respond homogenously across their ranges. We compared predictions from species and phenotype distribution models under future climate scenarios for Andropogon gerardii, a widely distributed, dominant grass found throughout the central United States. Phenotype data on aboveground biomass, height, leaf width, and chlorophyll content were obtained from 33 populations spanning a ~1000 km gradient that encompassed the majority of the species\’ environmental range. Species and phenotype distribution models were trained using current climate conditions and projected to future climate scenarios. We used permutation procedures to infer the most important variable for each model. The species-level response to climate was most sensitive to maximum temperature of the hottest month, but phenotypic variables were most sensitive to mean annual precipitation. The phenotype distribution models predict that A. gerardii could be largely functionally eliminated from where this species currently dominates, with biomass and height declining by up to ~60\% and leaf width by ~20\%. By the 2070s, the core area of highest suitability for A. gerardii is projected to shift up to ~700 km northeastward. Further, short-statured phenotypes found in the present-day short grass prairies on the western periphery of the species\’ range will become favored in the current core ~800 km eastward of their current location. Combined, species and phenotype models predict this currently dominant prairie grass will decline in prevalence and stature. Thus, sourcing plant material for grassland restoration and forage should consider changes in the phenotype that will be favored under future climate conditions. Phenotype distribution models account for the role of intraspecific variation in determining responses to anticipated climate change and thereby complement predictions from species distributions models in guiding climate adaptation strategies.

}, keywords = {LTER-KNZ}, doi = {10.1111/gcb.13666}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.13666}, author = {Smith, A.B. and Alsdurf, J. and Knapp, M. and S.G. Baer and Johnson, L.C.} } @article {KNZ001782, title = {Photosynthetic responses of a dominant C4 grass to an experimental heat wave are mediated by soil moisture}, journal = {Oecologia}, volume = {183}, year = {2017}, pages = {303-313}, abstract = {

Extreme heat waves and drought are predicted to increase in frequency and magnitude with climate change. These extreme events often co-occur, making it difficult to separate their direct and indirect effects on important ecophysiological and carbon cycling processes such as photosynthesis. Here, we assessed the independent and interactive effects of experimental heat waves and drought on photosynthesis in Andropogon gerardii, a dominant C4 grass in a native mesic grassland. We experimentally imposed a two-week heat wave at four intensity levels under two contrasting soil moisture regimes: a well-watered control and an extreme drought. There were three main findings from this study. First, the soil moisture regimes had large effects on canopy temperature, leading to extremely high temperatures under drought and low temperatures under well-watered conditions. Second, soil moisture mediated the photosynthetic response to heat; heat reduced photosynthesis under the well-watered control, but not under the extreme drought treatment. Third, the effects of heat on photosynthesis appeared to be driven by a direct thermal effect, not indirectly through other environmental or ecophysiological variables. These results suggest that while photosynthesis in this dominant C4 grass is sensitive to heat stress, this sensitivity can be overwhelmed by extreme drought stress.

}, keywords = {LTER-KNZ, Canopy temperature, Climate extremes, Drought, Ecophysiology, tallgrass prairie}, doi = {10.1007/s00442-016-3755-6}, url = {https://link.springer.com/article/10.1007\%2Fs00442-016-3755-6}, author = {Hoover, D.L. and Alan K. Knapp and M.D. Smith} } @mastersthesis {KNZ001871, title = {Physiological and morphological responses of grass species to drought}, volume = {MS Thesis}, year = {2017}, school = {Kansas State University}, type = {M.S. Thesis}, address = {Manhattan, KS}, abstract = {

The impacts of climate change over the next 100 years on North American grasslands are unknown. Climate change is projected to increase rainfall and seasonal temperature variability, leading to increased frequency of drought and decreased rainfall amounts for many grassland locations in the central Great Plains of North America. To increase our ability to predict the effects of a changing climate, I measured multiple morphological and physiological responses from a diverse suite of C3 and C4 grasses. Due to varying characteristics associated with the different photosynthetic pathways, these grass species respond differently to altered temperature and precipitation. I monitored grass physiology and microanatomy in conjunction with varying watered availability to replicate drought. In the second chapter, I observed leaf-level physiology and root level morphology of C3 and C4 grasses when exposed to 100\% water reduction. Results indicated that response to water reduction are not always dependent on the photosynthetic pathway. Root-level morphological measurements were found to vary significantly between species in the same genus; F. ovina had the highest specific root length (SRL), which is an indicator of tolerance to environmental variability. Results also indicated that grasses of interest have thresholds that when passed result in a photosynthetically inactive plant; however it was shown that they are able to recover to near pre-drought gas exchange rates when water is re-applied. The third chapter investigated both leaf-level physiology and morphology in dominant C4\¬ grasses across Kansas\’ rainfall gradient over the growing season. I hypothesized that variation within a species\’ physiology would be greater than its\’ morphology. I also hypothesized that morphology would predict variability in a species physiological response to changes in climate. This research discovered within a location and species, leaf morphology is fixed across the growing season. Strong correlations between leaf physiology and morphology were observed, however, the strength and relationship changed among the species compared. A. gerardii and P. virgatum exhibited opposing relationships when comparing their photosynthetic rates to the amount of bundle sheath cells. This result highlights strong species-specific relationship between physiology and morphology. My results illustrate the importance of utilizing plant physiology and morphology to understand how grasses may respond to future climate change scenarios.

}, keywords = {LTER-KNZ, Climate change, Drought; Great Plains, Ecophysiology, Grasslands, tallgrass prairie}, url = {http://krex.k-state.edu/dspace/handle/2097/36188}, author = {Bachle, Seton} } @article {KNZ001834, title = {Precipitation and environmental constraints on three aspects of flowering in three dominant tallgrass species}, journal = {Functional Ecology}, year = {2017}, month = {Mar-05-2018}, abstract = {
  1. Flower production can comprise up to 70\% of aboveground primary production in grasslands. Yet we know relatively little about how the environment and timing of rainfall determine flower productivity. Evidence suggests that deficits or additions of rainfall during phenlologically relevant periods (i.e. growth, storage, initiation of flowering, and reproduction) can determine flower production in grasslands.
  2. We used long-term data from the Konza Prairie LTER to test how fire, soil topography, and precipitation amounts during four phenologically relevant periods of the growing season constrain three aspects of flowering in three dominant C4 grass species. Specifically, we examined the probability of flowering, flowering stalk density, and individual flowering stalk biomass for Andropogon gerardii, Schizachyrium scoparium and Sorghastrum nutans.
  3. We found that each of the three species responded to the amount of precipitation during phenologically relevant periods in unique ways. All aspects of A. gerardii flowering were sensitive to precipitation during the flowering stalk elongation period (June 20 \– Aug 3). The probability of S. nutans flowering was partly determined by precipitation during the rapid growth phase (April 21 \– June 4), whereas flowering stalk density of this species depended on rainfall during flowering stalk elongation (June 20 \– Aug 3). In contrast, all aspects of flowering of S. scoparium were relatively independent of rainfall during any period.
  4. Our results demonstrate that three functionally similar, codominant C4 grass species respond differently to phenologically relevant precipitation periods. As a result, drought during any phenological window during the growing season can adversely impact biomass and flowering production of grasslands via species-specific reductions in flowering stalk density and biomass.
}, keywords = {LTER-KNZ}, doi = {10.1111/1365-2435.12904}, url = {https://besjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1365-2435.12904}, author = {Lemoine, Nathan P. and Dietrich, J.D. and M.D. Smith} } @article {KNZ001831, title = {Probing whole-stream metabolism: influence of spatial heterogeneity on rate estimates}, journal = {Freshwater Biology}, volume = {62}, year = {2017}, pages = {711 - 723}, abstract = {

1. Whole-stream metabolism has been estimated by measuring in-stream oxygen (O2) concentrations since the method was introduced over 50 years ago. However, the influence of measurement location and estimation method on metabolism rates is understudied. We examined how the placement of O2 probes (i.e. depth, separation from the thalweg), differences in methodology (1-station, 2-station, area-weighted) and reach lengths influenced estimated rates of whole-stream metabolism in a tallgrass prairie watershed.

2. Metabolism estimates made in the thalweg differed from estimates made in backwaters due to disconnection in flow, and estimates made in deep pools differed from surface estimates due to thermal stratification (temporary flow disconnection). The 1-station respiration estimates differed from short 2-station reach-scale estimates (c. 20 m) but were more similar to larger 2-station reach-scale estimates (c. 100 m). In contrast, the 1-station gross primary production was most similar to the short 2-station reaches occurring immediately upstream and became less similar at longer 2-station reach lengths. The different estimation methodologies (1-station, 2-station, area-weighted) accounting for the longest reach scale did not result in different metabolism rates.

3. The temporary phenomena of thermal stratification of stream pools during a warm day, which disconnected pool bottoms from the surface waters, likely affected not only the pool estimates but also estimates made in the downstream thalweg (i.e. an O2 deficit accrued from respiration during the day in the bottom of the pool abruptly moved downstream during mixing).

4. Oxygen probe placement mattered and affected rate estimates according to habitat type and reach length (i.e. scale) due to the influence of small-scale heterogeneity on community respiration. Selection of reach length can be critical for studies depending on whether local heterogeneity is of interest or should be averaged.

5. We conclude that the intuitive use of thalwegs and reaches that are at least 10 times the stream width are likely appropriate for whole-stream metabolism estimates, although the exact reach length necessary and potential stream-specific characteristics, such as stratified pools, need to be carefully considered in probe placement. We encourage other studies to report the placement characteristics of O2 probes in streams as well as consider the potential confounding factor of local habitat heterogeneity.

}, keywords = {LTER-KNZ}, doi = {10.1111/fwb.12896}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/fwb.12896}, author = {Siders, Adam C. and Larson, Danelle M. and R{\"u}egg, Janine and W. K. Dodds} } @article {KNZ001812, title = {Prospective evidence for independent nitrogen and phosphorus limitation of grasshopper (Chorthippus curtipennis) growth in a tallgrass prairie}, journal = {PLoS One}, volume = {12}, year = {2017}, pages = {e0177754}, abstract = {

Insect herbivores play a pivotal role in regulating plant production and community composition, and their role in terrestrial ecosystems is partly determined by their feeding behavior and performance among plants of differing nutritional quality. Historically, nitrogen (N) has been considered the primary limiting nutrient of herbivorous insects, but N is only one of many potential nutrients important to insect performance. Of these nutrients, phosphorus (P) is perhaps the most important because somatic growth depends upon P-rich ribosomal RNA. Yet relatively few studies have assessed the strength of P-limitation for terrestrial insects and even fewer have simultaneously manipulated both N and P to assess the relative strengths of N- and P-limitation. Here, we tested for potential N and P limitation, as well as N:P co-limitation, on Chorthippis curtipennis (Orthoptera, Acrididae), an abundant member of arthropod communities of central US prairies. Our results demonstrate weak evidence for both N and P limitation of C. curtipennis growth rates in laboratory feeding assays. Importantly, P-limitation was just as strong as N-limitation, but we found no evidence for NP co-limitation in our study. Furthermore, nutrient limitation was not apparent in field studies, suggesting that insect growth rates may be predominately controlled by other factors, including temperature and predation. Our results suggest that P should be jointly considered, along with N, as a primary determinant of herbivore feeding behavior under both current and future climate conditions.

}, keywords = {LTER-KNZ}, doi = {10.1371/journal.pone.0177754}, url = {https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0177754}, author = {Rode, M. and Lemoine, N.P. and M.D. Smith} } @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 {KNZ001731, title = {Patch-burn grazing increases habitat heterogeneity and biodiversity of small mammals in managed rangelands}, journal = {Ecosphere}, volume = {7}, year = {2016}, pages = {e01431}, abstract = {

Habitat heterogeneity is a key driver of biodiversity in many ecosystems. Wildlife inhabiting the native prairies of North America evolved in a heterogeneous mosaic of habitat conditions created by fire and grazing by native ungulates. Current rangeland management practices in the tallgrass prairie ecosystem evenly distribute fire and grazing across management units and promote homogeneous habitat conditions. Patch-burn grazing is a rangeland management strategy that seeks to restore heterogeneity to rangelands via fire-grazing interactions. Our 3.5-year study tested the effects of patch-burn grazing on habitat heterogeneity and small mammal community dynamics in the Flint Hills ecoregion of eastern Kansas. To study the ecological effects of patch-burn grazing, we sampled habitat conditions and the small mammal community. We assessed habitat conditions once each growing season in a negative control that was annually burned and grazed, a positive control that was burned every four years and ungrazed, and within each of three units of a patch-burn grazing experiment (PBG) managed with rotational fire. Habitat conditions were significantly different among treatments, and a principal components analysis showed that the patch-burn grazing treatment had higher canopy cover of forbs and habitat heterogeneity than our two control units. To sample the small mammal community, we conducted monthly live trapping of small mammals on two randomly located trap grids in each of our two controls and three units of our PBG treatment. Small mammal diversity was significantly higher in the patch-burn grazing treatment and in the positive control, vs. the negative control. Moreover, a canonical correspondence analysis showed that a fire-grazing interaction was the major driver structuring small mammal communities. Patch-burn grazing is an effective strategy for restoring heterogeneity to vegetative structure and composition, and can increase biodiversity of small mammals in managed rangelands in the tallgrass prairie ecosystem.

}, keywords = {LTER-KNZ}, doi = {10.1002/ecs2.1431}, url = {https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/ecs2.1431}, author = {Ricketts, A.M. and Sandercock, B.K.} } @phdthesis {KNZ001835, title = {Patterns and ecological consequences of water uptake, redistribution, and loss in tallgrass prairie}, volume = {PhD Dissertation}, year = {2016}, school = {Kansas State University}, type = {Ph.D. Thesis}, address = {Manhattan, KS}, abstract = {

Water availability is a key driver of many plant and ecosystem processes in tallgrass prairies, yet we have a limited understanding of how grassland plants utilize water through space and time. Considering that tallgrass prairies experience tremendous heterogeneity in soil resources, identifying spatiotemporal variation in plant ecohydrology is critical for understanding current drivers of plant responses to water and for predicting ecosystem responses to future changes in climate. Here, I investigated the patterns, drivers, and ecological consequences of plant water use (e.g., water uptake, water redistribution, and water loss) in a native tallgrass prairie located in northeastern Kansas, USA. Using a combination of leaf gas exchange, sap flow, and isotopic techniques, I addressed four main questions: 1) How does fire and grazing by bison impact use of water from different sources and niche overlap for common grasses, forbs, and shrubs? 2) Does hydraulic lift occur in grazed and ungrazed tallgrass prairie, and does this impact facilitation for water within grassland communities? 3) What are the patterns and drivers of nocturnal transpiration in common grassland species? 4) How does diel stem sap flow and canopy transpiration vary among common grassland species?

I found that bison grazing increased the depth of water uptake by Andropogon gerardii and Rhus glabra, reducing niche overlap with co-occurring species. Conversely, grazing did not affect hydraulic lift, which was generally uncommon and likely limited by nocturnal transpiration. Further, leaf gas exchange measurements indicated that nocturnal transpiration occurred commonly in tallgrass prairie plants and was greatest among grasses and early in the growing season. Nocturnal transpiration was not driven by vapor pressure deficit or soil moisture, as commonly observed in other systems, but was regulated by nocturnal stomatal conductance in most species. Finally, I found that daytime sap flow rates were variable among species and functional types, with larger flux rates among woody species. Nocturnal sap flow rates were more consistent across species, which caused nighttime sap flow and transpiration to account for a larger proportion of daily flux rates in grasses than in forbs or shrubs. These results show that water uptake, water redistribution, and water loss are all influenced by different biotic and abiotic drivers and have varying ecological impacts across a heterogeneous landscape. Additionally, extensive differences in water flux exist among co-occurring species and plant functional groups, which likely reflect varying strategies to tolerate water limitation. These results suggest that shifts in the abundance of these species with future climate changes, or with ecosystem state changes, will likely impact ecosystem-level water balance.

}, keywords = {LTER-KNZ, Grasslands, Isotopes, Plant physiology, Sap flow, Transpiration}, url = {http://krex.k-state.edu/dspace/handle/2097/34514}, author = {O{\textquoteright}Keefe, Kimberly} } @article {KNZ001739, title = {Productivity of North American grasslands is increased under future climate scenarios despite rising aridity}, journal = {Nature Climate Change}, volume = {6}, year = {2016}, pages = {710-714}, abstract = {

Grassland productivity is regulated by both temperature and the amount and timing of precipitation1, 2. Future climate change is therefore expected to influence grassland phenology and growth, with consequences for ecosystems and economies. However, the interacting effects of major shifts in temperature and precipitation on grasslands remain poorly understood and existing modelling approaches, although typically complex, do not extrapolate or generalize well and tend to disagree under future scenarios3, 4. Here we explore the potential responses of North American grasslands to climate change using a new, data-informed vegetation\–hydrological model, a network of high-frequency ground observations across a wide range of grassland ecosystems and CMIP5 climate projections. Our results suggest widespread and consistent increases in vegetation fractional cover for the current range of grassland ecosystems throughout most of North America, despite the increase in aridity projected across most of our study area. Our analysis indicates a likely future shift of vegetation growth towards both earlier spring emergence and delayed autumn senescence, which would compensate for drought-induced reductions in summer fractional cover and productivity. However, because our model does not include the effects of rising atmospheric CO2 on photosynthesis and water use efficiency5, 6, climate change impacts on grassland productivity may be even larger than our results suggest. Increases in the productivity of North American grasslands over this coming century have implications for agriculture, carbon cycling and vegetation feedbacks to the atmosphere.

}, keywords = {LTER-KNZ}, issn = {1758-678X}, doi = {10.1038/nclimate2942}, url = {https://www.nature.com/articles/nclimate2942}, author = {Hufkens, K. and Keenan, T.F. and Flanagan, L.B. and Scott, R.L. and Bernacchi, C.J. and Joo, E. and N. Brunsell and Verfaillie, J. and Richardson, A.D.} } @article {KNZ001767, title = {Patch-burn grazing effects on the ecological integrity of tallgrass prairie streams}, journal = {Journal of Environment Quality}, volume = {44}, year = {2015}, pages = {1148}, abstract = {

Conversion to agriculture, habitat fragmentation, and the loss of native grazers have made tallgrass prairie one of the most endangered ecosystems. One management option for the remaining prairie parcels, patch-burn grazing (PBG), applies a controlled burn to a portion of the prairie to attract cattle, creating a mosaic of more- and less-grazed patches. Although beneficial to cattle and grassland birds, the potential impacts of PBG on streams have not been studied, and a holistic approach is needed to ensure against adverse effects. We used a Before-After-Control-Impact design to assess potential impacts of PBG with and without riparian protection on tallgrass prairie headwater streams. We sampled stream macroinvertebrates and benthic organic matter 2 yr before and 2 yr during PBG treatments on two grazed watersheds with riparian fencing (fenced), two unfenced grazed watersheds (unfenced), and two ungrazed (control) watersheds. Very fine benthic organic matter increased significantly (51\%) in unfenced streams compared with controls ( \< 0.007), and fine particulate organic matter (\<1 mm and \>250 \µm) increased 3-fold in the unfenced streams compared with controls ( = 0.008). The contribution of fine inorganic sediments to total substrata increased 28\% in unfenced streams during PBG, which was significantly different from controls ( = 0.03). Additionally, the abundance of Ephemeroptera, Plecoptera, and Trichoptera taxa decreased from 7635 to 687 individuals m in unfenced streams, which was significantly lower than in control streams ( = 0.008). Our results indicate that PBG adversely influences prairie streams through sediment inputs and reductions in sensitive invertebrate taxa, but riparian fencing can alleviate these impacts.

}, keywords = {LTER-KNZ}, doi = {10.2134/jeq2014.10.0437}, url = {https://dl.sciencesocieties.org/publications/jeq/abstracts/44/4/1148}, author = {Jackson, K.E. and M.R. Whiles and W. K. Dodds and Reeve, J.D. and Vandermyde, J.M. and Rantala, H.M.} } @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.} } @mastersthesis {KNZ001696, title = {Plant responses to grazer-mediated habitat alterations in tallgrass prairie}, volume = {MS Thesis}, year = {2015}, school = {Kansas State University}, type = {M.S. Thesis}, address = {Manhattan, KS}, abstract = {

The effects of bison activities on forb diversity and cover have been well-established, but less is known about how forb life history is altered by bison-mediated habitat changes. This study had three main objectives: 1) to evaluate the hypothesis that release from aboveground competition with grasses may contribute to the increased cover and diversity of forbs in prairie grazed by bison relative to ungrazed prairie, 2) to determine whether differences in forb reproductive effort between grazed and ungrazed habitats were size-dependent, and 3) to look for evidence of a trade-off between allocation to vegetative and sexual reproduction. The growth, biomass allocation, and sexual reproduction of six common unpalatable perennial species were measured and compared between bison-grazed and ungrazed tallgrass prairie burned at 2-year intervals: Ambrosia psilostachya, Artemisia ludoviciana, Baptisia australis, Psoralidium tenuiflorum, Solidago canadensis, and Vernonia baldwinii. Vegetative reproduction was also measured for B. australis\¸ S. canadensis, and V. baldwinii. Light availability, canopy density and height, and percent cover of neighboring plants were measured in each studied individual\’s immediate neighborhood and compared between habitats to establish the possibility of differing aboveground competition. Aboveground competition may be lower in bison-grazed habitats, as evidenced by differences in habitat characteristics and plant performance found in this study. In bison-present habitats, sexual reproduction was elevated for all six species and average plant size was greater for all species except A. psilostachya. Vegetative reproduction was not clearly different between habitats for all three species examined. Sexual reproduction increased with size for all species, and the relationship differed significantly between habitats for all species except A. psilostachya. Allocation to vegetative reproduction was not generally related to aboveground biomass, nor was there a clear trade-off between allocation to vegetative and sexual reproduction. The results of this study provide evidence that release from aboveground competition with grasses promotes the growth and sexual reproduction of the studied species of forb, and that differences in sexual reproduction are not entirely size-dependent. Patterns in allocation to vegetative reproduction were less clear and were not clearly tied to sexual reproductive allocation.

}, keywords = {LTER-KNZ, Competition, forb, Grazing, Life history, Resource allocation, tallgrass prairie}, url = {http://krex.k-state.edu/dspace/handle/2097/19065}, author = {Zahner, A.} } @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 {KNZ001673, title = {Plains harvest mice in tallgrass prairie: abundance, habitat association and individual attributes}, journal = {Transactions of the Kansas Academy of Science}, volume = {117}, year = {2014}, pages = {167 -180}, abstract = {

The plains harvest mouse (Reithrodontomys montanus) inhabits grasslands in the Great Plains, but little is known about its ecology and natural history in native tallgrass prairie. We sampled native tallgrass prairie in spring and autumn by standard traplines on the Konza Prairie Biological Station during autumn 1981-spring 2013 and for shorter time periods in woodlands and brome fields. In addition to our long-term research, we studied small mammals on a large Prairie Grid (\∼13 ha) that was trapped intensively (about every 2 weeks except in winter) during 1984\–1987. Plains harvest mice (n = 39) were captured in native prairie but not in brome fields or wooded habitats. In all prairie sites, they were found to be rare (1.1 individuals/10,000 trap nights [TN]); in 14 Core Sites sampled for 32 years, abundance was higher in autumn (1.95/10,000 TN) than in spring (0.70/10,000 TN). It was not apparent that these low abundances were related to precipitation or another weather feature. On the Prairie Grid, plains harvest mice were associated with uplands and secondarily with slopes, whereas they avoided lowlands. Furthermore, they showed a positive response to conditions that are created during the first growing season following spring prescribed fires. Overall, 44\% of individuals were males and this value did not differ from a 1:1 sex ratio. Non-reproductive females (8.7 g) were slightly larger than males (8.3 g); only females occupied the largest body size class (11.0\–11.5 g). The smallest pregnant female weighed 9.0 g, whereas the smallest female that was lactating as evidenced by conspicuous mammae weighed 7.0 g. Pregnancies were recorded in spring, summer and autumn but not in winter; about one-third of females captured were pregnant. A juvenile (5.5 g) was captured in summer. We conclude that to understand this rare species (ca. 0.1\% of the small mammal community on Konza Prairie) even studies with small sample sizes are important to elucidate the natural history and ecology of the plains harvest mouse.

}, keywords = {LTER-KNZ, abundance, body size, fire effects, Konza Prairie, native tallgrass prairie, Reithrodontomys montanus, reproduction, sex ratio, topography}, doi = {10.1660/062.117.0302}, url = {https://doi.org/10.1660/062.117.0302}, author = {Kaufman, G.A. and D.W. Kaufman} } @article {KNZ001590, title = {Plant community response to loss of large herbivores differs between North American and South African savanna grasslands}, journal = {Ecology}, volume = {95}, year = {2014}, pages = {808 -816}, abstract = {

Herbivory and fire shape plant community structure in grass-dominated ecosystems, but these disturbance regimes are being altered around the world. To assess the consequences of such alterations, we excluded large herbivores for seven years from mesic savanna grasslands sites burned at different frequencies in North America (Konza Prairie Biological Station, Kansas, USA) and South Africa (Kruger National Park). We hypothesized that the removal of a single grass-feeding herbivore from Konza would decrease plant community richness and shift community composition due to increased dominance by grasses. Similarly, we expected grass dominance to increase at Kruger when removing large herbivores, but because large herbivores are more diverse, targeting both grasses and forbs, at this study site, the changes due to herbivore removal would be muted. After seven years of large-herbivore exclusion, richness strongly decreased and community composition changed at Konza, whereas little change was evident at Kruger. We found that this divergence in response was largely due to differences in the traits and numbers of dominant grasses between the study sites rather than the predicted differences in herbivore assemblages. Thus, the diversity of large herbivores lost may be less important in determining plant community dynamics than the functional traits of the grasses that dominate mesic, disturbance-maintained savanna grasslands.

}, keywords = {LTER-KNZ}, doi = {10.1890/13-1828.1}, url = {https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/13-1828.1}, author = {Koerner, S.E. and Burkepile, D.E. and Fynn, R.W.S. and Burns, C.E. and Eby, S. and Govender, N. and Hagenah, N. and Matchett, K.J. and Thompson, D.I. and K.R. Wilcox and Scott. L. Collins and Kirkman, K.P. and Alan K. Knapp and M.D. Smith} } @article {KNZ001595, title = {Plant-virus interactions and the agro-ecological interface}, journal = {European Journal of Plant Pathology}, volume = {138}, year = {2014}, pages = {529 -537}, abstract = {

As a result of human activities, an ever-increasing portion of Earth\’s natural landscapes now lie adjacent to agricultural lands. This border between wild and agricultural communities represents an agro-ecological interface, which may be populated with crop plants, weeds of crop systems, and non-crop plants that vary from exotic to native in origin. Plant viruses are important components of the agro-ecological interface because of their ubiquity, dispersal by arthropod vectors, and ability to colonize both crop and wild species. Here we provide an overview of research on plant-virus dynamics across this interface and suggest three research priorities: (1) an increased effort to identify and describe plant virus diversity and distribution in its entirety across agricultural and ecological boundaries; (2) multi-scale studies of virus transmission to develop predictive power in estimating virus propagation across landscapes; and (3) quantitative evaluation of the influence of viruses on plant fitness and populations in environmental contexts beyond crop fields. We close by emphasizing that agro-ecological interfaces are dynamic, influenced by the human-mediated redistribution of plants, vectors, and viruses around the world, climate change, and the development of new crops. Consideration of virus interactions within these environmentally complex systems promises new insight into virus, plant, and vector dynamics from molecular mechanisms to ecological consequences.

}, keywords = {LTER-KNZ, Agro-ecological interface, Crop, Plant fitness, Plant virus, Vector, Wild plant}, doi = {10.1007/s10658-013-0317-1}, url = {https://link.springer.com/article/10.1007\%2Fs10658-013-0317-1}, author = {Alexander, H.M. and Mauck, K.E. and Whitfield, A.E. and Garrett, K.A. and Malmstrom, C.M.} } @article {KNZ001566, title = {Patterns of diversity and adaptation in Glomeromycota from three prairie grasslands}, journal = {Molecular Ecology}, volume = {22}, year = {2013}, pages = {2573 -2587}, abstract = {

Arbuscular mycorrhizal (AM) fungi are widespread root symbionts that often improve the fitness of their plant hosts. We tested whether local adaptation in mycorrhizal symbioses would shape the community structure of these root symbionts in a way that maximizes their symbiotic functioning. We grew a native prairie grass (Andropogon gerardii) with all possible combinations of soils and AM fungal inocula from three different prairies that varied in soil characteristics and disturbance history (two native prairie remnants and one recently restored). We identified the AM fungi colonizing A. gerardii roots using PCR amplification and cloning of the small subunit rRNA gene. We observed 13 operational taxonomic units (OTUs) belonging to six genera in three families. Taxonomic richness was higher in the restored than the native prairies with one member of the Gigaspora dominating the roots of plants grown with inocula from native prairies. Inoculum source and the soil environment influenced the composition of AM fungi that colonized plant roots. Correspondingly, host plants and AM fungi responded significantly to the soil\–inoculum combinations such that home fungi often had the highest fitness and provided the greatest benefit to A. gerardii. Similar patterns were observed within the soil\–inoculum combinations originating from two native prairies, where five sequence types of a single Gigaspora OTU were virtually the only root colonizers. Our results indicate that indigenous assemblages of AM fungi were adapted to the local soil environment and that this process occurred both at a community scale and at the scale of fungal sequence types within a dominant OTU.

}, keywords = {LTER-KNZ}, doi = {10.1111/mec.12268}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/mec.12268}, author = {Ji, B. and Gehring, C.A. and G.T. Wilson and Miller, R.M. and Flores-Renteria, L. and Johnson, N.C.} } @inbook {KNZ001759, title = {Phenologies of North American Grasslands and Grasses}, booktitle = {Phenology: An Integrative Environmental Science, 2e}, year = {2013}, pages = {197-210}, publisher = {Springer Netherlands}, organization = {Springer Netherlands}, chapter = {11}, abstract = {

Inquiry into the phenologies of grasslands and grasses in North America has progressed substantially in the past decade. Four themes of the recent phenological research are surveyed: (1) the role of exotic and invasive species in affecting grasslands phenology; (2) the role of water and belowground dynamics on phenologies; (3) how experimental manipulations of grasslands have affected constitutive phenologies; and (4) advances in the remote sensing of grasslands. The phyllochron concept used in ontogenetic studies of grass species is discussed in light of grasslands phenology and its link between daylength and thermal time

}, keywords = {LTER-KNZ}, doi = {10.1007/978-94-007-6925-0_11}, url = {https://link.springer.com/chapter/10.1007\%2F978-94-007-6925-0_11}, author = {Henebry, G.M.}, editor = {MD Schwartz} } @article {KNZ001499, title = {Physiological and growth responses of switchgrass (Panicum virgatum L.) in native stands under passive air temperature manipulation}, journal = {Global Change Biology-Bioenergy}, volume = {5}, year = {2013}, pages = {683 -692}, abstract = {

In the central Great Plains of North America, climate change predictions include increases in mean annual temperature of 1.5\–5.5 \°C by 2100. Ecosystem responses to increased temperatures are likely to be regulated by dominant plant species, such as the potential biofuel species Panicum virgatum (switchgrass) in the tallgrass prairie. To describe the potential physiological and whole-plant responses of this species to future changes in air temperatures, we used louvered open-sided chambers (louvered OSC; 1 \× 1 m, adjustable height) to passively alter canopy temperature in native stands of P. virgatum growing in tallgrass prairie at varying topographic positions (upland/lowland). The altered temperature treatment decreased daily mean temperatures by 1 \°C and maximum temperatures by 4 \°C in May and June, lowered daytime stomatal conductance and transpiration, decreased tiller density, increased specific leaf area, and delayed flowering. Among topographic contrasts, aboveground biomass, flowering tiller density, and tiller weight were greater in lowland sites compared to upland sites, with no temperature treatment interactions. Differences in biomass production responded more to topography than the altered temperature treatment, as soil water status varied considerably between topographic positions. These results indicate that while water availability as a function of topography was a strong driver of plant biomass, many leaf-level physiological processes were responsive to the small decreases in daily mean and maximum temperature, irrespective of landscape position. The varying responses of leaf-level gas exchange and whole-plant growth of P. virgatum in native stands to altered air temperature or topographic position illustrate that accurately forecasting yields for P. virgatum in mixed communities will require greater integration of physiological responses to simulated climate change (increased temperature) and resource availability over natural environmental gradients (soil moisture).

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1757-1707.2012.01204.x}, url = {https://onlinelibrary.wiley.com/doi/full/10.1111/j.1757-1707.2012.01204.x}, author = {Hartman, J.C. and Jesse B. Nippert} } @article {KNZ001555, title = {Population origin and genome size do not impact Panicum virgatum (switchgrass) responses to variable precipitation}, journal = {Ecosphere}, volume = {4}, year = {2013}, pages = {37 -}, abstract = {

Population-level adaptation to broad-scale regional climates or within-population variation in genome size of the genetically and phenotypically diverse C4 grass, Panicum virgatum (switchgrass), may influence the responses of this species to future precipitation variability associated with climate change. Therefore, we investigated P. virgatum responses to water variability between natural populations collected across a latitudinal gradient and among individuals spanning a range of genomes sizes within these populations. P. virgatum plants from natural populations originating from Kansas, Oklahoma, and Texas, U.S.A, received frequent, small precipitation events (\“ambient\”) or infrequent, large precipitation events (\“altered\”) to simulate contrasting rainfall variability expected for this region. We measured leaf-level physiology, aboveground biomass and genome size for each individual. Gas exchange rates and aboveground biomass varied significantly by population origin but did not differ by genome size. Altered precipitation treatments reduced leaf-level physiological rates; however this result did not vary by population or genome size. Our results suggest that trait variation in P. virgatum is primarily attributed to population-level adaptation across a latitudinal gradient, not genome size, and that neither population-level adaptation nor genome size may be important predictors of P. virgatum responses to future climatic conditions.

}, keywords = {LTER-KNZ}, doi = {10.1890/ES12-00339.1}, url = {https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/ES12-00339.1}, author = {O{\textquoteright}Keefe, K. and Tomeo, N. and Jesse B. Nippert and Springer, C.J.} } @article {KNZ001714, title = {Positive association between social and extra-pair mating in a polygynous songbird, the dickcissel (Spiza americana)}, journal = {Behavioral Ecology and Sociobiology}, volume = {67}, year = {2013}, month = {Jan-02-2013}, pages = {243 - 255}, abstract = {In polygynous species, males appear to gain additional offspring by pairing with multiple females simultaneously. However, this may not be true if some females copulate outside of the social pair bond. Polygynous males could experience lower paternity because of trade-offs among gaining multiple social mates, guarding fertility with these mates, and pursuing extra-pair matings. Alternatively, polygynous males could simultaneously gain extra social mates and have high paternity, either because of female preferences or because of male competitive attributes. We tested four predictions stemming from these hypotheses in a facultatively polygynous songbird, the dickcissel (Spiza americana). Unlike most previous studies, we found that males with higher social mating success (harem size) also tended to have higher within-pair paternity and that the number of extra-pair young a male sired increased significantly with his social mating success. Females that paired with mated males were not more likely to produce extra-pair young. In contrast, extra-pair paternity was significantly lower in the nests of females whose nesting activity overlapped that of another female on the same territory. This pattern of mating was robust to differences in breeding density. Indeed, breeding density had no effect on either extra-pair mating or on the association between polygyny and paternity. Finally, nest survival increased with harem size. This result, combined with the positive association between polygyny and paternity, contributed to significantly higher realized reproductive success by polygynous male dickcissels.}, keywords = {LTER-KNZ, density, Extra-pair paternity, Female choice, Mating patterns, Polygyny, Trade offs}, issn = {0340-5443}, doi = {10.1007/s00265-012-1444-y}, url = {http://link.springer.com/10.1007/s00265-012-1444-yhttp://www.springerlink.com/index/pdf/10.1007/s00265-012-1444-y}, author = {Sousa, Bridget F. and Westneat, David F.} } @article {KNZ001474, title = {Precipitation timing and grazer performance in a tallgrass prairie}, journal = {Oikos}, volume = {122}, year = {2013}, pages = {191 -198}, abstract = {

Changes in precipitation amount and variability have the potential to alter the structure and function of grasslands, but we know little about how changes in the timing of precipitation might affect grasslands. Here, we analyze long-term records from a tallgrass prairie to show that shifts in the timing of precipitation during the growing season have little effect on primary productivity or grass reproduction, but can greatly affect grazer performance. While greater late-season precipitation increases the weight gain of adult and young bison, greater mid-season precipitation decreases their weight gain. In addition, calving rates are lower after years with greater mid-season precipitation and higher after years with greater late-season precipitation. As well-timed drought can actually increase grazer weight gain and reproduction, it will be necessary to generate predictions of within-season distribution of precipitation to successfully forecast future grazer performance.

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1600-0706.2012.20400.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1600-0706.2012.20400.x}, author = {Craine, J.M. and Towne, E.G. and Tolleson, D. and Jesse B. Nippert} } @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 {KNZ001496, title = {Past, present, and future roles of long-term experiments in the LTER Network}, journal = {Bioscience}, volume = {62}, year = {2012}, pages = {377 -389}, abstract = {

The US National Science Foundation\–funded Long Term Ecological Research (LTER) Network supports a large (around 240) and diverse portfolio of long-term ecological experiments. Collectively, these long-term experiments have (a) provided unique insights into ecological patterns and processes, although such insight often became apparent only after many years of study; (b) influenced management and policy decisions; and (c) evolved into research platforms supporting studies and involving investigators who were not part of the original design. Furthermore, this suite of long-term experiments addresses, at the site level, all of the US National Research Council\&$\#$39;s Grand Challenges in Environmental Sciences. Despite these contributions, we argue that the scale and scope of global environmental change requires a more-coordinated multisite approach to long-term experiments. Ideally, such an approach would include a network of spatially extensive multifactor experiments, designed in collaboration with ecological modelers that would build on and extend the unique context provided by the LTER Network.

}, keywords = {LTER-KNZ, Climate change, global change, long-term research, LTER Network, multifactor experiments}, doi = {10.1525/bio.2012.62.4.9}, url = {https://academic.oup.com/bioscience/article/62/4/377/243762}, author = {Alan K. Knapp and M.D. Smith and Hobbie, S.E. and Scott. L. Collins and Fahey, T.J. and Hansen, G.J.A. and Landis, D.A. and Kimberly J. La Pierre and Melillo, J.M. and Seastedt, T.R. and Shaver, G.R. and Webster, J.R.} } @article {KNZ001457, title = {Phylogenetics of Morus (Moraceae) inferred from ITS and trnL-trnF sequence data}, journal = {Systematic Botany}, volume = {37}, year = {2012}, pages = {442 -450}, abstract = {

Morus (Tribe Moreae, Moraceae) consists of ca. 13 species of trees distributed in Asia, Africa, Europe, and North, Central, and South America. The broad geographical distribution of the genus, overlapping ranges of many taxa, and documented hybridization between some species present interesting questions of taxonomy, phylogeny, and biogeography. Phylogenetic data for Morus also contribute to higher level taxonomic work in the family. We used sequence data from ITS of the nrDNA and the chloroplast trnL-trnF intergenic spacer to study phylogenetic relationships of Morus. Phylogenies based on separate data sets were not statistically incongruent, and the combined tree reveals that Morus, as currently circumscribed, is non-monophyletic. Subgenus Morus (sensu Leroy) is resolved as a clade and consists of two well-supported clades: one of Asian taxa and one of North American taxa. Sampled members of the genus Trophis (two, including the type) form a clade sister to subgenus Morus. Morus mesozygia (Africa; subgenus Afromorus) and M. insignis (Neotropics; subgenus Gomphomorus), which have not been included to date in other phylogenetic studies of the family, are placed outside the subgenus Morus-Trophis clade. This work is an important step in elucidating relationships of Morus and along with other recent phylogenetic studies in Moraceae, underscores the need for further work within Tribe Moreae to clarify natural generic relationships.

}, keywords = {LTER-KNZ, ITS, Moraceae, Moreae, Morus, phylogeny, trnL-trnF}, doi = {https://doi.org/10.1600/036364412X635485}, url = {https://bioone.org/journals/Systematic-Botany/volume-37/issue-2/036364412X635485/Phylogenetics-of-iMorus-i-Moraceae-Inferred-from-ITS-and-itrnL/10.1600/036364412X635485.full}, author = {Nepal, M.P. and Ferguson, C.J.} } @article {KNZ001516, title = {Plant and soil responses to high and low diversity grassland restoration practices}, journal = {Environmental Management}, volume = {49}, year = {2012}, pages = {412 -424}, abstract = {

The USDA\’s Conservation Reserve Program (CRP) has predominantly used only a few species of dominant prairie grasses (CP2 practice) to reduce soil erosion, but recently has offered a higher diversity planting practice (CP25) to increase grassland habitat quality. We quantified plant community composition in CP25 and CP2 plantings restored for 4 or 8 years and compared belowground properties and processes among restorations and continuously cultivated soils in southeastern Nebraska, USA. Relative to cultivated soils, restoration increased soil microbial biomass (P = 0.033), specifically fungi (P \< 0.001), and restored soils exhibited higher rates of carbon (C) mineralization (P = 0.010). High and low diversity plantings had equally diverse plant communities; however, CP25 plantings had greater frequency of cool-season (C3) grasses (P = 0.007). Older (8 year) high diversity restorations contained lower microbial biomass (P = 0.026), arbuscular mycorrhizal fungi (AMF) biomass (P = 0.003), and C mineralization rates (P = 0.028) relative to 8 year low diversity restorations; older plantings had greater root biomass than 4 year plantings in all restorations (P = 0.001). Low diversity 8 year plantings contained wider root C:N ratios, and higher soil microbial biomass, microbial community richness, AMF biomass, and C mineralization rate relative to 4 year restorations (P \< 0.050). Net N mineralization and nitrification rates were lower in 8 year than 4 year high diversity plantings (P = 0.005). We attributed changes in soil C and N pools and fluxes to increased AMF associated with C4 grasses in low diversity plantings. Thus, reduced recovery of AMF in high diversity plantings restricted restoration of belowground microbial diversity and microbially-mediated soil processes over time.

}, keywords = {LTER-KNZ, Conservation reserve program, Nitrogen mineralization, Phospholipid fatty acids, Soil microbial community, tallgrass prairie}, doi = {10.1007/s00267-011-9787-0}, url = {https://link.springer.com/article/10.1007\%2Fs00267-011-9787-0}, author = {E.M. Bach and S.G. Baer and Six, J.} } @article {KNZ001620, title = {Predator-prey interactions in a grassland food chain vary with temperature and food quality}, journal = {Oikos}, volume = {122}, year = {2012}, pages = {977 -986}, abstract = {

Because species interactions are often context-dependent, abiotic factors such as temperature and biotic factors such as food quality may alter species interactions with potential consequences to ecosystem structure and function. For example, altered predator\–prey interactions may influence the dynamics of trophic cascades, affecting net primary production. In a three-year field experiment, we manipulated a plant\–grasshopper\–spider food chain in mesic tallgrass prairie to investigate the effects of temperature and food quality on grasshopper performance, and to understand the direct and indirect tritrophic interactions that contribute to trophic cascades. Because spiders are active at cooler temperatures than grasshoppers in our system, we hypothesized that predator effects would be strongest in cooled treatments, and weakest in warmed treatments. Grasshopper spider interactions were highly context-dependent and varied significantly with food quality, temperature treatment and year. Spiders most often reduced grasshopper survival in the cooled and ambient temperature treatments, but had little to no effect on grasshopper survival in the warmed treatments, as hypothesized. In some years, plants compensated for grasshopper herbivory and trophic cascades were not observed despite significant effects of predators on grasshopper survival. However, in the year they were observed, trophic cascades only occurred in cooled treatments where predator effects on grasshoppers were strongest. Predicting ecosystem responses to climate change will require an understanding of how temperature influences species interactions. Our results demonstrate that changes in daily temperature regimes can alter predator\–prey interactions among arthropods with consequences for ecosystem processes such as primary production and the relative importance of top\–down and bottom\–up processes.

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1600-0706.2012.20419.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1600-0706.2012.20419.x}, author = {Laws, A. and Anthony Joern} } @article {KNZ001491, title = {Predicting plant responses to mycorrhizae: integrating evolutionary history and plant traits}, journal = {Ecology Letters}, volume = {15}, year = {2012}, pages = {689 -695}, abstract = {

We assessed whether (1) arbuscular mycorrhizal colonization of roots (RC) and/or plant responses to arbuscular mycorrhizae (MR) vary with plant phylogeny and (2) MR and RC can be more accurately predicted with a phylogenetic predictor relative to a null model and models with plant trait and taxonomic predictors. In a previous study, MR and RC of 95 grassland species were measured. We constructed a phylogeny for these species and found it explained variation in MR and RC. Next, we used multiple regressions to identify the models that most accurately predicted plant MR. Models including either phylogenetic or phenotypic and taxonomic information similarly improved our ability to predict MR relative to a null model. Our study illustrates the complex evolutionary associations among species and constraints of using phylogenetic information, relative to plant traits, to predict how a plant species will interact with AMF.

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1461-0248.2012.01786.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1461-0248.2012.01786.x}, author = {Reinhart, K.O. and G.T. Wilson and Rinella, M.J.} } @article {KNZ001355, title = {Patterns of macroinvertebrate production, trophic structure, and energy flow along a tallgrass prairie stream continuum}, journal = {Limnology and Oceanography}, volume = {56}, year = {2011}, pages = {887 -898}, abstract = {

We estimated benthic organic matter standing stocks, macroinvertebrate production, food-web structure, and stream metabolism along a longitudinal continuum of Kings Creek at Konza Prairie Biological Station in Kansas. Benthic macroinvertebrates were sampled for 1 yr from three stream reaches (grass, shrub, gallery forest). Total habitat-weighted production ranged from 9.1 g to 31.9 g ash-free dry weight m\−2 yr\−1 with the grass headwaters accounting for the highest production. Functional group contributions to production were similar along the continuum, with collector\–gatherers (40\–56\% of total) and predators (23\–38\%) dominating all reaches. Detrital pathways appeared to account for most energy flow in all reaches, and all reaches were net heterotrophic on all dates when metabolism was measured, except for the grass headwater reach in spring. Predators were well-represented and consumed 65\–107\% of total macroinvertebrate production, whereas scrapers (11\–15\%), shredders (2\–4\%), and filterers (\< 1\%) consumed relatively small percentages of available resources. Dominance of predators suggested top-down controls are important in this system. However, changes in energy flow through other groups reflected longitudinal variation in resource availability. This prairie stream continuum conforms to some predictions of conceptual stream continua models, but biotic interactions, which are often not considered, may override some predicted responses to changes in the physical template.

}, keywords = {LTER-KNZ}, doi = {10.4319/lo.2011.56.3.0887}, url = {https://aslopubs.onlinelibrary.wiley.com/doi/abs/10.4319/lo.2011.56.3.0887}, author = {Whiting, D.P. and M.R. Whiles and Stone, M.L.} } @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 {KNZ001389, title = {Physiological drought tolerance and the structuring of tallgrass assemblages}, journal = {Ecosphere}, volume = {2}, year = {2011}, pages = {48 -}, abstract = {

Drought is a defining characteristic of many grasslands worldwide. Yet we have little understanding of how drought structures grassland communities and the degree to which physiological drought tolerance advantages plants in grasslands. We characterized physiological drought tolerance (Ψcrit) for a large number of species in a mesic grassland community (Konza Prairie, KS, USA). We then examined the relationships between Ψcrit and a number of other key functional traits, and tested whether physiological tolerance of drought underlay success across a number of ecological contrasts\—topographic position, burn frequency, and grazing\—with 17 years of abundance data. Physiological drought tolerance of Konza species covered almost the full range known to plants globally. Consistently, physiologically drought-tolerant species had thin roots, while associations with other traits were inconsistent across functional groups. In this mesic grassland, physiological drought tolerance appears to increase the abundance of plants in xeric uplands, but does not in the mesic lowlands. Physiological drought tolerance did not alter species responses to changes in burning or grazing. In contrast to Ψcrit, species with high root tissue density were more abundant in uplands and lowlands than species with low root tissue density largely irrespective of grazing or burning regimes. In all, drought appears to have a limited role in structuring the Konza plant community. As such, more severe or frequent droughts in the region would likely restructure the Konza plant community in ways that are currently not observable.

}, keywords = {LTER-KNZ}, doi = {10.1890/ES11-00023.1}, url = {https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/ES11-00023.1}, author = {Tucker, S.S. and Craine, J.M. and Jesse B. Nippert} } @article {KNZ001444, title = {Population genetic structure and landscape connectivity of the Eastern Yellowbelly Racer (Coluber constrictor flaviventris) in the contiguous tallgrass prairie of northeastern Kansas, USA}, journal = {Landscape Ecology}, volume = {26}, year = {2011}, pages = {281 -294}, abstract = {

The tallgrass prairie of North America has undergone widespread habitat loss and fragmentation (\<4\% remains). The Flint Hills region of Kansas and Oklahoma is the largest tallgrass prairie remaining and therefore provides an opportunity to study the population genetic structure of grassland species in a relatively contiguous landscape and set a baseline for evaluating changes when the habitat is fragmented. We adopted a landscape genetics approach to identify how landscape structure affected dispersal, population genetic structure, and landscape connectivity of the Eastern Yellowbelly Racer (Coluber constrictor flaviventris) across a 13,500-km2 landscape in northeastern Kansas, USA. The racer population had high allelic diversity, high heterozygosity, and was maintaining migration-drift equilibrium. Autocorrelation between genetic and geographic distance revealed that racers exhibited restricted dispersal within 3 km, and isolation-by-distance. Significant isolation-by-distance occurred at broad regional scales (\>100 km), but because of sufficient gene flow between locations, we were unable to define discrete subpopulations using Bayesian clustering analyses. Resistance distance, which considers the permeability of habitats, did not explain significant variation in genetic distance beyond Euclidean distance alone, suggesting that racers are not currently influenced by landscape composition. In northeastern Kansas, racers appear to be an abundant and continuously distributed snake that perceives the landscape as well connected with no cover type currently impeding snake dispersal or gene flow.

}, keywords = {LTER-KNZ, Autocorrelation, conservation, dispersal, Fragmentation, Gene flow, grassland, Isolation-by-distance, Landscape genetics, Microsatellites, Snake}, doi = {10.1007/s10980-010-9554-2}, url = {https://link.springer.com/article/10.1007\%2Fs10980-010-9554-2}, author = {Klug, P.E. and Wisely, S.M. and With, K.A.} } @article {KNZ001450, title = {Positive feedbacks amplify rates of woody encroachment in mesic tallgrass prairie}, journal = {Ecosphere}, volume = {2}, year = {2011}, pages = {121 -}, abstract = {

Over the last century, many grasslands worldwide have transitioned from a graminoid to a tree/shrub-dominated state in a short period of time, a phenomenon referred to as woody encroachment. Positive feedbacks and bi-stability are thought to be important drivers of woody encroachment, but there is little empirical evidence to suggest that positive feedbacks accelerate the woody encroachment of mesic grasslands. In mesic tallgrass prairie, shrub establishment does not directly facilitate seedling establishment. Yet, shrub establishment may facilitate the clonal spread of existing shrubs into nearby patches, because clonal reproduction might circumvent barriers that typically limit woody seedlings. Our results show that when Cornus drummondii (the predominate encroacher of mesic tallgrass prairie) extends rhizomatous stems into open grasslands, these stems use the same deep soil water sources as mature stems\—thereby avoiding competition with grasses and gaining access to a reliable water source. In addition, herbaceous fuel concentrations are lower at the shrub/grass interface than in open grasslands, reducing the potential impacts of subsequent grassland fires. We propose that the release from resource and fire limitation results in a positive feedback loop as clonal stems are able to extend into surrounding patches, circumvent demographic barriers, mature, and spread by developing their own clonal stems. Long-term data on site (26 years) corroborates this interpretation: the size of deep-rooted clonal shrub species has increased 16-fold and their cover has increased from 0 to 27\%, whereas the cover of shallow-rooted species (both clonal and non-clonal) has only increased marginally. Together, these results suggest that (1) positive feedbacks can facilitate mesic woody encroachment and (2) bi-stability exists in mesic tallgrass prairie.

}, keywords = {LTER-KNZ}, doi = {10.1890/ES11-00212.1}, url = {https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/ES11-00212.1}, author = {Z. Ratajczak and Jesse B. Nippert and Hartman, J.C. and Ocheltree, T.W.} } @article {KNZ001503, title = {Potential ecological impacts of switchgrass (Panicum virgatum L.) biofuel cultivation in the Central Great Plains, USA}, journal = {Biomass and Bioenergy}, volume = {35}, year = {2011}, pages = {3415 -3421}, abstract = {

Switchgrass (Panicum virgatum L.) is a broadly adapted warm-season grass species native to most of the central and eastern United States. Switchgrass has been identified as a potential biofuel species because it is a native species that requires minimal management, and has a large potential to sequester carbon underground. Since the 1990\’s, switchgrass has been bred to produce cultivars with increased biomass and feedstock quality. This review addresses potential ecological consequences of widespread switchgrass cultivation for biofuel production in the central United States. Specifically, this review address the ecological implications of changing use of marginal and CRP land, impacts on wildlife, potentials for disease and invasions, and changes in soil quality through reductions in erosion, decomposition rates, and carbon sequestrations. A central theme of the review is the utility of maintaining landscape heterogeneity during switchgrass biofuel production. This includes implementing harvest rotations, no till farming, and mixed species composition. If negative ecological consequences of switchgrass cultivation are minimized, biofuel production using this species has economical and environmental benefits.

}, keywords = {LTER-KNZ, Carbon sequestration, Crop rotation, CRP land, Landscape heterogeneity, Marginal land, SOC}, doi = {10.1016/j.biombioe.2011.04.055}, url = {https://www.sciencedirect.com/science/article/pii/S0961953411002935?via\%3Dihub}, author = {Hartman, J.C. and Jesse B. Nippert and Orozco, R.A. and Springer, C.J.} } @article {KNZ001448, title = {Productivity is a poor predictor of plant species richness}, journal = {Science}, volume = {333}, year = {2011}, pages = {1750 -1753}, abstract = {

For more than 30 years, the relationship between net primary productivity and species richness has generated intense debate in ecology about the processes regulating local diversity. The original view, which is still widely accepted, holds that the relationship is hump-shaped, with richness first rising and then declining with increasing productivity. Although recent meta-analyses questioned the generality of hump-shaped patterns, these syntheses have been criticized for failing to account for methodological differences among studies. We addressed such concerns by conducting standardized sampling in 48 herbaceous-dominated plant communities on five continents. We found no clear relationship between productivity and fine-scale (meters\−2) richness within sites, within regions, or across the globe. Ecologists should focus on fresh, mechanistic approaches to understanding the multivariate links between productivity and richness.

}, keywords = {LTER-KNZ}, doi = {10.1126/science.1204498}, url = {http://science.sciencemag.org/content/333/6050/1750}, author = {P. Adler and Seabloom, E.W. and E.T. Borer and Hillebrand, H. and Hautier, Y. and Hector, A. and Harpole, W.S. and O{\textquoteright}Halloran, L.R. and Grace, J.B. and Anderson, T.M. and J.D. Bakker and L.A. Biederman and C.S. Brown and Buckley, Y.M. and Calabrese, L.B. and Chu, C.J. and Cleland, E.E. and Scott. L. Collins and Cottingham, K.L. and Crawley, M.J. and Damschen, E.I. and Davies, K.F. and DeCrappeo, N.M. and Fay, P.A. and Firn, J. and Frater, P. and Gasarch, E.I. and Gruner, D.S. and Hagenah, N. and HilleRisLambers, J. and Humphries, H.C. 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 Lambrinos, J.G. and Li, W. and MacDougall, A.S. and McCulley, R.L. and Melbourne, B.A. and Mitchell, C.E. and Joslin L. Moore} } @article {KNZ001529, title = {Permanent genetic resources added to molecular ecology resources database}, journal = {Molecular Ecology Resources}, volume = {9}, year = {2010}, month = {2010-01-01 00:00}, pages = {1559}, chapter = {1460}, abstract = {

This article documents the addition of 512 microsatellite marker loci and nine pairs of Single Nucleotide Polymorphism (SNP) sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Alcippe morrisonia morrisonia, Bashania fangiana, Bashania fargesii, Chaetodon vagabundus, Colletes floralis, Coluber constrictor flaviventris, Coptotermes gestroi, Crotophaga major, Cyprinella lutrensis, Danaus plexippus, Fagus grandifolia, Falco tinnunculus, Fletcherimyia fletcheri, Hydrilla verticillata, Laterallus jamaicensis coturniculus, Leavenworthia alabamica, Marmosops incanus, Miichthys miiuy, Nasua nasua, Noturus exilis, Odontesthes bonariensis, Quadrula fragosa, Pinctada maxima, Pseudaletia separata, Pseudoperonospora cubensis, Podocarpus elatus, Portunus trituberculatus, Rhagoletis cerasi, Rhinella schneideri, Sarracenia alata, Skeletonema marinoi, Sminthurus viridis, Syngnathus abaster, Uroteuthis (Photololigo) chinensis, Verticillium dahliae, Wasmannia auropunctata, and Zygochlamys patagonica. These loci were cross-tested on the following species: Chaetodon baronessa, Falco columbarius, Falco eleonorae, Falco naumanni, Falco peregrinus, Falco subbuteo, Didelphis aurita, Gracilinanus microtarsus, Marmosops paulensis, Monodelphis Americana, Odontesthes hatcheri, Podocarpus grayi, Podocarpus lawrencei, Podocarpus smithii, Portunus pelagicus, Syngnathus acus, Syngnathus typhle,Uroteuthis (Photololigo) edulis, Uroteuthis (Photololigo) duvauceli and Verticillium albo-atrum. This article also documents the addition of nine sequencing primer pairs and sixteen allele specific primers or probes for Oncorhynchus mykiss and Oncorhynchus tshawytscha; these primers and assays were cross-tested in both species.

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1755-0998.2009.02759.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1755-0998.2009.02759.x}, author = {Glenn R. Almany} } @article {KNZ001301, title = {Phosphorus biogeochemistry across a precipitation gradient in grasslands of central North America}, journal = {Journal of Arid Environments}, volume = {74}, year = {2010}, pages = {954 -961}, abstract = {

Soil P transformations and distribution studies under water limited conditions that characterize many grasslands may provide further insight into the importance of abiotic and biotic P controls within grass-dominated ecosystems. We assessed transformations between P pools across four sites spanning the shortgrass steppe, mixed grass prairie, and tallgrass prairie along a 400-mm precipitation gradient across the central Great Plains. Pedon total elemental and constituent mass balance analyses reflected a pattern of increased chemical weathering from the more arid shortgrass steppe to the more mesic tallgrass prairie. Soil surface A horizon P accumulation was likely related to increased biocycling and biological mining. Soluble P, a small fraction of total P in surface A horizons, was greatest at the mixed grass sites. The distribution of secondary soil P fractions across the gradient suggested decreasing Ca-bound P and increasing amounts of occluded P with increasing precipitation. Surface A horizons contained evidence of Ca-bound P in the absence of CaCO3, while in subsurface horizons the Ca-bound P was associated with increasing CaCO3 content. Calcium-bound P, which dominates in water-limited systems, forms under different sets of soil chemical conditions in different climatic regimes, demonstrating the importance of carbonate regulation of P in semi-arid ecosystems.

}, keywords = {LTER-KNZ, Grassland ecosystems, Phosphorus biogeochemistry, Sequential phosphorus extraction, Soil weathering}, doi = {10.1016/j.jaridenv.2010.01.003}, url = {https://www.sciencedirect.com/science/article/abs/pii/S014019631000011X?via\%3Dihub}, author = {Ippolito, J.A. and Blecker, S.W. and Freeman, C.L. and McCulley, R.L. and John M. Blair and Kelly, E.F.} } @article {KNZ001274, title = {Plant nitrogen and phosphorus limitation in 98 North American grassland soils}, journal = {Plant and Soil}, volume = {334}, year = {2010}, pages = {73 -84}, abstract = {

The availability of nutrients is a critical determinant of ecological dynamics in grasslands, but the relationships between soil resource availability and nutrient limitation across ecosystems are not clear. To better understand how soil nutrient availability determines nutrient limitation in vegetation, we grew the same species of grass (Schizachyrium scoparium) in 98 North American grassland soils and fertilized them factorially with nitrogen (N) and phosphorus (P). On average adding N, P, and the two nutrients together increased biomass relative to unfertilized plants by 81\%, 22\%, and 131\%, respectively. Plants grown on low-P soils were not primarily limited by P. Instead, these plants were colimited by N and P, while plants grown on high-P soils were primarily limited by N and only secondarily limited by P. Limitation was not predicted by total soil N. The preponderance of colimitation between N and P on low-P soils suggests that low P availability alters the N cycle to constrain supplies to plants such that N and P are made available in proportion to their demand by plants.

}, keywords = {LTER-KNZ, Colimitation, Grasslands, nitrogen, Phosphorus, stoichiometry}, doi = {10.1007/s11104-009-0237-1}, url = {https://link.springer.com/article/10.1007\%2Fs11104-009-0237-1}, author = {Craine, J.M. and Jackson, R.D.} } @article {KNZ001235, title = {Parent-absent begging in the Brown-headed Cowbird (Molothrus ater): the role of short-term need and nestmate size}, journal = {Behavioral Ecology and Sociobiology}, volume = {63}, year = {2009}, pages = {707 -717}, abstract = {

Although it is well-established that nestlings of many altricial species beg when parents are away from the nest, we have a poor understanding of parent-absent begging in brood parasites, including the proximate factors that may influence begging frequency and intensity. In this study, I examined how parent-absent begging was influenced by competitive asymmetries between host and Brown-headed Cowbird (Molothrus ater) nestlings under disparate levels of short-term need. Food-deprived cowbird nestlings begged more frequently and for a greater proportion of parent-absent period than when food-supplemented, with similar patterns observed in hosts of different sizes. In contrast, three metrics of cowbird begging intensity varied relative to host size but not due to differences in short-term need. Cowbirds consistently begged more frequently and intensively than host nestlings for a given level of short-term need, providing evidence that cowbird begging displays are more frequent and intense than non-parasitic nestlings during both feeding visits and parent-absent periods. In sum, the frequency of begging by cowbirds was only influenced by short-term need, whereas begging intensity during parent-absent events was only influenced by the host against which cowbirds competed. This study demonstrates that host size and short-term need had differing influences on the frequency and intensity of parent-absent begging in cowbirds, although both factors are likely important in limiting the evolution of parent-absent begging in cowbirds. Because it appears to provide no immediate benefits yet may decrease fitness, parent-absent begging should be included in future theoretical models investigating the evolution of begging displays in nestling birds.

}, keywords = {LTER-KNZ, begging, brown-headed cowbird, generalist brood parasite, Molothrus ater, Parent-absent begging}, doi = {10.1007/s00265-008-0704-3}, url = {https://link.springer.com/article/10.1007\%2Fs00265-008-0704-3}, author = {Rivers, J.W.} } @inbook {KNZ001257, title = {Plant pathogens as indicators of climate change}, booktitle = {Climate and Global Change: Observed Impacts on Planet Earth}, year = {2009}, pages = {425 -437}, publisher = {Elsevier}, organization = {Elsevier}, keywords = {LTER-KNZ}, url = {http://pdf.usaid.gov/pdf_docs/PNADU515.pdf}, author = {Garrett, K.A. and Nita, M. and De Wolf, E.D. and Gomez, L. and Sparks, A.H.}, editor = {Letcher, T.} } @article {KNZ001244, title = {Polymorphic microsatellite markers for the striped skunk, Mephitis mephitis, and other mephitids}, journal = {Molecular Ecology Resources}, volume = {9}, year = {2009}, pages = {383 -385}, abstract = {

We report 10 polymorphic microsatellite loci primers developed for striped skunks (Mephitis mephitis), a widespread mesocarnivore in North America. Numbers of alleles in these loci ranged from seven to 14 and the observed heterozygosity ranged from 0.76 to 1.0. These primers will be useful for studying population dynamics of skunks where rabies is endemic and will be useful to estimate genetic relatedness among females sharing winter dens. Most of these primers amplify across species within the Mephitidae.

}, keywords = {LTER-KNZ, hog-nosed skunk, hooded skunk, Mephitis mephitis, microsatellite primers, spotted skunk, striped skunk}, doi = {10.1111/j.1755-0998.2008.02463.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1755-0998.2008.02463.x}, author = {Dragoo, J.W. and Coan, K.E. and Moore, K.A. and Henke, S.E. and Fleisher, R.C. and Wisely, S.M.} } @article {KNZ001177, title = {Phenotypic correlates and survival consequences of male mating success in lek-mating Greater Prairie-chickens (Tympanuchus cupido)}, journal = {Behavioral Ecology and Sociobiology}, volume = {62}, year = {2008}, pages = {1377 -1388}, abstract = {

Female choice and male\–male aggression are two modes of sexual selection that can lead to elaboration of male morphological and behavioral traits. In lek-mating species, male mating success is often strongly skewed, and it is puzzling why variation in male traits is still observed given directional female choice. If male traits correlated with reproductive success are honest signals of male quality, there may be survival costs associated with the expression of those traits. In this study, we examined whether morphological, behavioral, and territorial traits are correlated with male mating success and survival in the lek-mating greater prairie-chicken (Tympanuchus cupido). We introduce a novel application of multinomial discrete choice models for analysis of female mate choice behavior. We found that behavioral and territorial attributes showed 6.5 times more variability among males than morphological traits. Both display and aggressive behaviors were strong predictors of male mating success, suggesting that both female choice and male\–male aggression were important in determining mating success among male greater prairie-chickens. Moreover, annual survival of male prairie-chickens was independent of mating success and male traits. Females appear to be choosing males based on behavioral traits where large variation exists between males (coefficient of variation \>30\%). Behavioral traits were the most important factor in determining mating success of male prairie-chickens, but the mechanism underlying this relationship is unknown. In the future, experimental manipulations of male hormones or parasite loads could bridge the proximate mechanisms and ultimate consequences of factors mediating male mating success in lek-mating grouse.

}, keywords = {LTER-KNZ, Galliformes, Life history trade-off, mate choice, reproduction, Sexual selection}, doi = {10.1007/s00265-008-0566-8}, url = {https://link.springer.com/article/10.1007\%2Fs00265-008-0566-8}, author = {Nooker, J.K. and Sandercock, B.K.} } @article {KNZ001241, title = {Plant winners and losers during grassland N eutrophication differ in biomass allocation and mycorrhizas}, journal = {Ecology}, volume = {89}, year = {2008}, pages = {2868 -2878}, abstract = {

Human activities release tremendous amounts of nitrogenous compounds into the atmosphere. Wet and dry deposition distributes this airborne nitrogen (N) on otherwise pristine ecosystems. This eutrophication process significantly alters the species composition of native grasslands; generally a few nitrophilic plant species become dominant while many other species disappear. The functional equilibrium model predicts that, compared to species that decline in response to N enrichment, nitrophilic grass species should respond to N enrichment with greater biomass allocation aboveground and reduced allocation to roots and mycorrhizas. The mycorrhizal feedback hypothesis states that the composition of mycorrhizal fungal communities may influence the composition of plant communities, and it predicts that N enrichment may generate reciprocal shifts in the species composition of mycorrhizal fungi and plants. We tested these hypotheses with experiments that compared biomass allocation and mycorrhizal function of four grass ecotypes (three species), two that gained and two that lost biomass and cover in response to long-term N enrichment experiments at Cedar Creek and Konza Long-Term Ecological Research grasslands. Local grass ecotypes were grown in soil from their respective sites and inoculated with whole-soil inoculum collected from either fertilized (FERT) or unfertilized (UNFERT) plots. Our results strongly support the functional equilibrium model. In both grassland systems the nitrophilic grass species grew taller, allocated more biomass to shoots than to roots, and formed fewer mycorrhizas compared to the grass species that it replaced. Our results did not fully support the hypothesis that N-induced changes in the mycorrhizal fungal community were drivers of the plant community shifts that accompany N eutrophication. The FERT and UNFERT soil inoculum influenced the growth of the grasses differently, but this varied with site and grass ecotype in both expected and unexpected ways suggesting that ambient soil fertility or other factors may be interacting with mycorrhizal feedbacks.

}, keywords = {LTER-KNZ}, doi = {10.1890/07-1394.1}, url = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/07-1394.1}, author = {Johnson, N.C. and Rowland, D.L. and Corkidi, L. and Allen, E.B.} } @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 {KNZ001157, title = {Predicting NH4+ uptake andmineralization in prairie streams by using chamber incubation and short-termnutrient addition experiments}, journal = {Freshwater Biology}, volume = {52}, year = {2008}, pages = {102 -112}, keywords = {LTER-KNZ}, author = {O{\textquoteright}Brien, J.M. and W. K. Dodds} } @article {KNZ001119, title = {Photosynthetic traits in C3 and C4 grassland species in mesocosm and field environments}, journal = {Environmental and Experimental Botany}, volume = {60}, year = {2007}, pages = {412 -420}, abstract = {The North American tallgrass prairie is composed of a diverse mix of C3 and C4 plant species that are subject to multiple resource limitations. C4 grasses dominate this ecosystem, purportedly due to greater photosynthetic capacity and resource-use efficiency associated with C4 photosynthesis. We tested the hypothesis that intrinsic physiological differences between C3 and C4 species are consistent with C4 grass dominance by comparing leaf gas exchange and chlorophyll fluorescence variables for seven C4 and C3 herbaceous species (legumes and non-legumes) in two different settings: experimental mesocosms and natural grassland sites. In the mesocosms, C4 grasses had higher photosynthetic rates, water potentials and water-use efficiency than the C3 species. These differences were absent in the field, where photosynthetic rates declined similarly among non-leguminous species. Thus, intrinsic photosynthetic advantages for C4 species measured in resource-rich mesocosms could not explain the dominance of C4 species in the field. Instead, C4 dominance in this ecosystem may depend more on the ability of the grasses to grow rapidly when resources are plentiful and to tolerate multiple limitations when resources are scarce.}, keywords = {LTER-KNZ, A:Ci curves, C3, C4, Chlorophyll fluorescence, gas exchange, Konza, tallgrass prairie}, doi = {10.1016/j.envexpbot.2006.12.012}, author = {Jesse B. Nippert and Fay, P.A. and Alan K. Knapp} } @inbook {KNZ001124, title = {Primary production: Guiding principles and standards for measurement}, booktitle = {Principles and Standards for Measuring Net Primary Production}, year = {2007}, pages = {3 -11}, publisher = {Oxford University Press, NY}, organization = {Oxford University Press, NY}, abstract = {This chapter serves as an introduction to the book, outlining the general considerations in the measurement of net primary production (NPP) in particular biomes or groups of biomes (e.g. savannas, grasslands and forests), the temporal and spatial variation and principles of site selection, field sampling and laboratory procedures for NPP measurement, and statistical analysis and quality assurance/quality control.}, keywords = {LTER-KNZ}, url = {http://www.cabdirect.org/abstracts/20073139615.html?freeview=true}, author = {Fahey, T.J. and Alan K. Knapp}, editor = {Fahey, T.J. and Alan K. Knapp} } @book {KNZ001123, title = {Principles and Standards for Measuring Net Primary Production}, series = {Principles and Standards for Measuring Net Primary Production}, year = {2007}, pages = {268 -}, publisher = {Oxford University Press, NY}, organization = {Oxford University Press, NY}, abstract = {Standardized approaches for the measurement of primary production {\textemdash} the rate of energy storage in the organic matter of plants {\textemdash} are essential to facilitate scientific comparisons and syntheses as well as policy and management on global climate change and the carbon cycle. This book provides an overview of the principles that should underlie every program of measurement of primary production in the Earth{\textquoteright}s major biomes. Each of seven biome-based chapters provides an overview of essential features of primary production processes in the biome and detailed descriptions of the procedures used to quantify primary production in grasslands, shrublands, forests, peatlands and tundra, salt marshes, marine pelagic, and freshwater ecosystems. Recent advances in the measurement of belowground production in terrestrial biomes are described. The book also provides detailed guidelines for information management based upon current experiences of the US Long-Term Ecological Research network. Advanced techniques are described for scaling up empirical measurements of primary production using remotely-sensed information. Finally, the principles and practices for quantifying uncertainty in primary production measurements are explored using examples from various biomes.}, keywords = {LTER-KNZ, belowground, biomes, carbon cycle, Ecosystems, remote sensing, uncertainty}, author = {Fahey, T.J. and Alan K. Knapp}, editor = {Fahey, T.J. and Alan K. Knapp} } @phdthesis {KNZ001137, title = {Patterns of plant diversity and their management across South African rangelands}, volume = {PhD Dissertation }, year = {2006}, pages = {1 -245}, school = {University of Cape Town}, type = {Ph.D. Thesis}, address = {Cape Town, South Africa}, keywords = {LTER-KNZ}, url = {https://open.uct.ac.za/handle/11427/6200}, author = {Uys, R.G.} } @article {KNZ001009, title = {Partitioning of nitrogen over five growing seasons in tallgrass prairie}, journal = {Ecology}, volume = {86}, year = {2005}, pages = {1280 -1287}, abstract = {Annual spring burning of tallgrass prairie increases plant biomass production despite losses of N and lower net N mineralization. To better understand how burning influences the cycling of N in prairie, 15N was injected to soil as NH4+, and the partitioning between plant and soil N pools was followed over five growing seasons in annually burned and unburned prairie. Applied 15N was rapidly immobilized with <2\% and 11\% of the 15N remaining in inorganic forms six days after application in burned and unburned prairie, respectively. Seventy-seven percent (burned prairie) and 70\% (unburned prairie) of the applied 15N was initially recovered as soil organic N (oN), with a majority accounted for in microbial biomass. Plants contained \~{}20\% of the applied N with the largest portion recovered from roots regardless of burning. At the end of the first growing season, only 55\% of the applied 15N was recovered from the unburned prairie, while 85\% was recovered from burned prairie. The total 15N content of the plants changed little during the first growing season, but the portion recovered in the rhizomes increased, indicating belowground N storage. Total recovery and distribution of applied N changed little from the end of the first to the end of the second season growing season. Accumulations of 15N within the plants decreased greatly between the second and fifth growing seasons, but N lost from plants was accounted for in oN. Conservation of N by plants and tight cycling of N within the root zone suggest mechanisms by which prairie can be a highly productive ecosystem despite limited N availability. The immobilization of potentially mineralized N within the root zone increased with burning, offsetting the loss of N to fire probably by reducing leaching and denitrification losses.}, keywords = {LTER-KNZ}, doi = {10.1890/03-0790}, author = {Dell, C.J. and Williams, M.A. and C. W. Rice} } @article {KNZ00959, title = {Pollinator importance andtemporal variation in a population of Phlox divaricata L. (Polemoniaceae)}, journal = {American Midland Naturalist}, volume = {154}, year = {2005}, pages = {42 -54}, abstract = {Temporal variation in climatic conditions is a regular occurrence for most early spring flowering plants in temperate regions, often producing variation in available pollinators. Evaluating the effectiveness and importance of pollinators to a plant population provides an indication of the relative influence of each visitor on a population{\textquoteright}s reproductive success and selection on floral traits. This study examined pollinator activity and its effect on seed set in a population of Phlox divaricata L. (Polemoniaceae), investigating variation over the 24-h day and the flowering season for two consecutive years. Eleven species, representing three orders of insects, were documented visiting the study population, although lepidopterans (four species, particularly Hemaris diffinis and Megalographa biloba) accounted for 90\% of all visitation. The highest visitation rates (and resulting seed set) occurred during the morning and afternoon diurnal time periods and the evening crepuscular time period. The relative frequencies of the different visitors varied over the 24-h day and between flowering seasons. Most visitors that could be evaluated were found to be effective pollinators. Thus, a pollinator{\textquoteright}s importance to reproductive success was generally dictated by its visitation frequency, H. diffinis being the most important pollinator. This study highlights the importance of considering temporal variation in effective pollinators in species experiencing variable environmental conditions.}, keywords = {LTER-KNZ}, doi = {10.1674/0003-0031(2005)154[0042:PIATVI]2.0.CO;2}, author = {Wiggam, S. and Ferguson, C.J.} } @article {KNZ00889, title = {Plant community responses to resource availability and heterogeneity during restoration}, journal = {Oecologia}, volume = {139}, year = {2004}, pages = {617 -629}, abstract = {Availability and heterogeneity of resources have a strong influence on plant community structure in undisturbed systems, as well as those recovering from disturbance. Less is known about the role of resource availability and heterogeneity in restored communities, although restoration provides a valuable opportunity to test our understanding of factors that influence plant community assembly. We altered soil nitrogen (N) availability and soil depth during a prairie restoration to determine if the availability and/or heterogeneity of soil resources influenced plant community composition in restored grassland communities. Plant community responses to three levels of N availability (ambient, enriched by fertilization, and reduced by carbon amendment) and two levels of soil depth (deep and shallow) were evaluated. In addition, we evaluated plant community responses to four whole plot heterogeneity treatments created from the six possible combinations of soil N availability and soil depth. The soil depth treatment had little influence on community structure during the first 3 years of restoration. Total diversity and richness declined over time under annual N enrichment, whereas diversity was maintained and richness increased over time in soil with reduced N availability. Non-native species establishment was lowest in reduced-N soil in the initial year, but their presence was negligible in all of the soil N treatments by the second year of restoration. Panicum virgatum, a native perennial C4 grass, was the dominant species in all soil N treatments by year three, but the magnitude of its dominance was lowest in the reduced-N soil and highest in enriched-N soil. Consequently, the relative cover of P. virgatum was strongly correlated with community dominance and inversely related to diversity. The differential growth response of P. virgatum to soil N availability led to a higher degree of community similarity to native prairie in the reduced-N treatment than in the enriched-N treatment. There were no differences in plant community structure among the four whole plot-level heterogeneity treatments, which all exhibited the same degree of similarity to native prairie. Diversity and community heterogeneity in the whole-plot treatments appeared to be regulated by the dominant species{\textquoteright} effect on light availability, rather than soil N heterogeneity per se. Our results indicate that a strong differential response of a dominant species to resource availability in a restored community can regulate community structure, diversity, and similarity to the native (or target) community, but the importance of resource heterogeneity in restoring diversity may be dampened in systems where a dominant species can successfully establish across a range of resource availability.}, keywords = {LTER-KNZ, diversity, grassland, nitrogen, tallgrass prairie}, doi = {10.1007/s00442-004-1541-3}, author = {S.G. Baer and John M. Blair and Scott. L. Collins and Alan K. Knapp} } @article {KNZ00850, title = {Predation by gray catbird on brown thrasher eggs}, journal = {Southwestern Naturalist}, volume = {49}, year = {2004}, pages = {101 -103}, abstract = {

The gray catbird (Dumetella carolinensis) has been documented visiting and breaking the eggs of artificial nests, but the implications of such observations are unclear because there is little cost in depredating an undefended nest. During the summer of 2001 at Konza Prairie Biological Station, Kansas, we videotaped a gray catbird that broke and consumed at least 1 egg in a brown thrasher (Toxostoma rufum) nest. Our observation was consistent with egg predation because the catbird consumed the contents of the damaged egg after breaking it. The large difference in body mass suggests that a catbird (37 g) destroying eggs in a thrasher (69 g) nest might risk injury if caught in the act of predation and might explain why egg predation by catbirds has been poorly documented. Our observation indicated that the catbird should be considered as an egg predator of natural nests and that single-egg predation of songbird nests should not be attributed to egg removal by female brown-headed cowbirds (Molothrus ater) without additional evidence.

}, keywords = {LTER-KNZ}, doi = {http://dx.doi.org/10.1894/0038-4909(2004)049<0101:PBGCOB>2.0.CO;2}, author = {Rivers, J.W. and Sandercock, B.K.} } @mastersthesis {KNZ00913, title = {Pollination and floral scent biology of Phlox divaricata L. (Polemoniaceae)}, volume = {MS Thesis}, year = {2003}, pages = {1 -66}, school = {Kansas State University}, type = {M.S. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ}, author = {Harper, S.} } @article {KNZ00872, title = {Population differences in effects of fish on Physia integra refuge use}, journal = {American Midland Naturalist}, volume = {150}, year = {2003}, pages = {51 -57}, abstract = {Prey populations exposed to different sets of predators often adopt distinct antipredator behaviors. We investigated the refuge use of a freshwater pulmonate snail, Physa integra, in the presence and absence of fish predators. Over 80\% of snails in sites with fish used refuge, while only 50\% used refuge in sites without fish. Snails in sites with fish were also significantly smaller than snails in sites without fish. In a laboratory experiment, the presence of fish did not alter the habitat use of snails collected from a no-fish site, whereas snails collected from a site with fish used refuge when exposed to predation risk. These results support the hypothesis that P. integra exhibit local behavioral adaptations to their predator regime.}, keywords = {LTER-KNZ}, doi = {10.1674/0003-0031(2003)150[0051:PDIEOF]2.0.CO;2}, author = {Bernot, R.J.} } @article {KNZ00863, title = {Productivity responses to altered rainfall patterns in a C4-dominated grassland}, journal = {Oecologia}, volume = {137}, year = {2003}, pages = {245 -251}, abstract = {Rainfall variability is a key driver of ecosystem structure and function in grasslands worldwide. Changes in rainfall patterns predicted by global climate models for the central United States are expected to cause lower and increasingly variable soil water availability, which may impact net primary production and plant species composition in native Great Plains grasslands. We experimentally altered the timing and quantity of growing season rainfall inputs by lengthening inter-rainfall dry intervals by 50\%, reducing rainfall quantities by 30\%, or both, compared to the ambient rainfall regime in a native tallgrass prairie ecosystem in northeastern Kansas. Over three growing seasons, increased rainfall variability caused by altered rainfall timing with no change in total rainfall quantity led to lower and more variable soil water content (0{\textendash}30 cm depth), a ~10\% reduction in aboveground net primary productivity (ANPP), increased root to shoot ratios, and greater canopy photon flux density at 30 cm above the soil surface. Lower total ANPP primarily resulted from reduced growth, biomass and flowering of subdominant warm-season C4 grasses while productivity of the dominant C4 grass Andropogon gerardii was relatively unresponsive. In general, vegetation responses to increased soil water content variability were at least equal to those caused by imposing a 30\% reduction in rainfall quantity without altering the timing of rainfall inputs. Reduced ANPP most likely resulted from direct effects of soil moisture deficits on root activity, plant water status, and photosynthesis. Altered rainfall regimes are likely to be an important element of climate change scenarios in this grassland, and the nature of interactions with other climate change elements remains a significant challenge for predicting ecosystem responses to climate change.}, keywords = {LTER-KNZ, Climate change, Konza Prairie, Net primary productivity, Precipitation, soil moisture}, doi = {10.1007/s00442-003-1331-3}, author = {P. Fay and Carlisle, J.D. and Alan K. Knapp and John M. Blair and Scott. L. Collins} } @article {KNZ00831, title = {Phrynosoma cornutum (Texas horned lizard) reproduction}, journal = {Herpetological Review}, volume = {33}, year = {2002}, pages = {308 -309}, keywords = {LTER-KNZ}, author = {Owens, A. and Trager, M. and Horne, E.} } @article {KNZ00788, title = {Physiological and morphological traits of exotic, invasive exotic, and native plant species in tallgrass prairie}, journal = {International Journal of Plant Sciences}, volume = {162}, year = {2001}, pages = {785 -792}, abstract = {We compared 13 traits of invasive exotic, noninvasive exotic, and ecologically similar native species to determine if there are generalizable differences among these groups that relate to persistence and spread of exotic species in tallgrass prairie plant communities. When species were grouped as invasive (two species), noninvasive (five species), and native (six species), no differences were found for the suite of traits examined, likely because of the high variability within and between groups. However, when exotic species, regardless of invasiveness, were compared with the native species, specific leaf area was ca. 40\% higher for the exotic species, a result that is consistent with that of other studies. This pattern was also observed for five of seven pairwise comparisons of exotic and native species with similar life history traits. In contrast, total end-of-season biomass was as much as three times higher for the native species in five of seven of the native-exotic species pairs. For other traits, differences between exotic and native species were species-specific and were generally more numerous for noninvasive than for invasive exotic species pair-wise comparisons. Thus, contrary to predictions, exotic species capable of successfully invading tallgrass prairie did not differ considerably from native species in most traits related to resource utilization and carbon gain. Moreover, invasive exotic species, those capable of displacing native species and dominating a community, were not distinct for the observed traits from their native counterparts. These results indicate that other traits, such as the ability to respond to resource pulses or herbivory, may explain more effectively why certain invasive species are able to invade these communities aggressively.}, keywords = {LTER-KNZ, biomass allocation, grassland, invasive plants, photosynthesis, specific leaf area}, doi = {10.1086/320774}, author = {M.D. Smith and Alan K. Knapp} } @article {KNZ00740, title = {Patterns and determinants of potential carbon gain in the C3 evergreen Yucca glauca (Liliaceae) in a C4 grassland}, journal = {American Journal of Botany}, volume = {87}, year = {2000}, pages = {230 -236}, abstract = {Yucca glauca is a C3 evergreen rosette species locally common in the C4-dominated grasslands of the central Great Plains. Most congeners of Y. glauca are found in deserts, and Y. glauca{\textquoteright}s morphological similarities to desert species (steeply angled leaves, evergreen habit) may be critical to its success in grasslands. We hypothesized that the evergreen habit of Y. glauca, coupled with its ability to remain physiologically active at cool temperatures, would allow this species to gain a substantial portion of its annual carbon budget when the C4 grasses are dormant. Leaf-level gas exchange was measured over an 18-mo period at Konza Prairie in northeast Kansas to assess the annual pattern of potential C gain. Two short-term experiments also were conducted in which nighttime temperatures were manipulated to assess the cold tolerance of this species. The annual pattern of C gain in Y. glauca was bimodal, with a spring productive period (maximum monthly photosynthetic rate = 21.1 {\textpm} 1.97 μmol{\textperiodcentered}m-2{\textperiodcentered}s-1) in March through June, a period of midseason photosynthetic depression, and a fall productive period in October (15.6 {\textpm} 1.25 μmol{\textperiodcentered}m-2{\textperiodcentered}s-1). The steeply angled leaves resulted in interception of photon flux density at levels above photosynthetic saturation throughout the year. Reduced photosynthetic rates in the summer may have been caused by low soil moisture, but temperature was strongly related (r2 = 0.37) to annual variations in photosynthesis, with nocturnal air temperatures below -5{\textdegree}C in the late fall and early spring, and high air temperatures (>32{\textdegree}C) in the summer, limiting gas exchange. Overall, 31\% of the potential annual carbon gain in Y. glauca occurred outside the {\textquotedblleft}frost-free{\textquotedblright} period (April{\textendash}October) at Konza Prairie and 43\% occurred when the dominant C4 grasses were dormant. Future climates that include warmer minimum temperatures in the spring and fall may enhance the success of Y. glauca relative to the C4 dominants in these grasslands.}, keywords = {LTER-KNZ, Climate change, cold tolerance, evergreen, Grasslands, Liliaceae, photosynthesis, tallgrass prairie, Water relations, Yucca}, url = {http://www.amjbot.org/content/87/2/230.short}, author = {Maragni, L.A. and Alan K. Knapp and McAllister, C.A.} } @phdthesis {KNZ00887, title = {Patterns of mechanisms of eastern redcedar (Juniperus virginiana) expansion into tallgrass prairie in the Flint Hills KS}, volume = {PhD Dissertation}, year = {2000}, pages = {1 -106}, school = {Kansas State University}, type = {Ph.D. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ, tallgrass prairie}, author = {Hoch, G.A.} } @article {KNZ00735, title = {Patterns of species density and productivity at different spatial scales in herbaceous plant communities}, journal = {Oikos}, volume = {89}, year = {2000}, pages = {417 -427}, abstract = {A major challenge in evaluating patterns of species richness and productivity involves acquiring data to examine these relationships empirically across a range of ecologically significant spatial scales. In this paper, we use data from herb-dominated plant communities at six Long-Term Ecological Research (LTER) sites to examine how the relationship between plant species density and above-ground net primary productivity (ANPP) differs when the spatial scale of analysis is changed. We quantified this relationship at different spatial scales in which we varied the focus and extent of analysis: (1) among fields within communities, (2) among fields within biomes or biogeographic regions, and (3) among communities within biomes or biogeographic regions. We used species density (D=number of species per m2) as our measure of diversity to have a comparable index across all sites and scales. Although we expected unimodal relationships at all spatial scales, we found that spatial scale influenced the form of the relationship. At the scale of fields within different grassland communities, we detected a significant relationship at only one site (Minnesota old-fields), and it was negative linear. When we expanded the extent of analyses to biogeographic regions (grasslands or North America), we found significant unimodal relationships in both cases. However, when we combined data to examine patterns among community types within different biogeographic regions (grassland, alpine tundra, arctic tundra, or North America), we did not detect significant relationships between species density and ANPP for any region. The results of our analyses demonstrate that the spatial scale of analysis {\textendash} how data are aggregated and patterns examined {\textendash} can influence the form of the relationship between species density and productivity. It also demonstrates the need for data sets from a broad spectrum of sites sampled over a range of scales for examining challenging and controversial ecological hypotheses.}, keywords = {LTER-KNZ}, doi = {10.1034/j.1600-0706.2000.890301.x}, author = {Gross, K.L. and M.R. Whiles and Gough, L. and Inouye, R. and Cox, S.B.} } @article {KNZ00750, title = {Prairie vegetation and soil nutrient responses to ungulate carcasses}, journal = {Oecologia}, volume = {122}, year = {2000}, pages = {232 -239}, abstract = {The impact of large ungulate carcasses on grassland dynamics was investigated by monitoring vegetation and soil nutrients in 50-cm circular zones around the center of bison (Bos bison), cattle (B. taurus), and deer (Odocoileus virginianus) carcasses. An ungulate carcass creates an intense localized disturbance that varies with animal size and the season of death. Unlike other natural disturbances, carcasses deposit a concentrated pulse of nutrients into the soil. One year after death, inorganic nitrogen concentrations were significantly higher in the inner 50 cm at both adult and juvenile carcass sites than in surrounding prairie. Areas around a carcass became zones of fertility that favored different components of the vegetation and stimulated biomass production. Species richness and diversity at the center of carcass sites were lowest 1 year after death, but increased significantly in subsequent years. However, warm-season perennial grasses declined near the center of carcass sites and did not recover. Five years after death, ungulate carcass sites remained disturbed patches that harbored vegetation characteristically different in composition and stature from surrounding prairie. By providing a niche for species not normally found in undisturbed prairie, carcasses increased community heterogeneity and may play an important role in adding spatial complexity to grassland ecosytems.}, keywords = {LTER-KNZ, Carrion, disturbance, Soil nutrients, succession, tallgrass prairie}, doi = {10.1007/PL00008851}, author = {Towne, E.G.} } @article {KNZ00722, title = {Predictive models for grazing distribution: a GIS approach}, journal = {Journal of Range Management}, volume = {53}, year = {2000}, pages = {39 -46}, abstract = {Grazing distribution and forage use patterns are important influences on rangeland ecosystems. Spatial patterns of grazing by domestic cattle (Bos taurus) were observed over 2 consecutive years under 2 grazing systems, intensive-early stocking and season-long stocking. The purposes were to determine factors influencing observed patterns and develop predictive models for grazing distribution and forage removal. Field-collected data on grazing distribution were linked with associated geophysical properties of pastures utilizing a GIS. Separate models were developed to predict grazing distribution and forage utilization using a backward stepwise regression procedure. The forage utilization model was linked with grazing distribution by utilizing Tobit analysis. Nineteen independent variables were used to interpret the observed variation in grazing distribution. Comparison of predicted probability of grazing values from the model with the observed grazing distribution in a hold-out data set yielded a close fit (R=.99). Eighteen independent variables were included in the forage removal model. Comparison of predicted forage removal with observed values in a hold-out data set yielded a poor fit (R=.28). Lack of forage quality variables probably accounts for the poor performance of the forage removal model. Differences in the success of the 2 models support the hypothesis that grazing distribution and forage utilization operate at different spatial scales and parameters. The use of GIS holds promise as a technique for developing useful predictive models for range management.}, keywords = {LTER-KNZ}, doi = {10.2307/4003390}, author = {B. Brock and Owensby, C.E.} } @article {KNZ00711, title = {Phenological influences on the albedo of prairie grassland and crop fields}, journal = {International Journal of Biometeorology}, volume = {42}, year = {1999}, pages = {153 -157}, abstract = {The albedo of land surfaces is strongly affected by transient surface conditions. For a vegetated surface, albedo can change with soil moisture, fractional canopy cover, and plant phenology as well as solar zenith angle (θs). In this study, the relationships between albedo and plant phenology in prairie grassland and agricultural crops were examined by removing the effect of variations in θs. Albedos were evaluated at a constant θs, which was assigned to be 20{\textdegree} in this study. For days with a minimum θs larger than 20{\textdegree}, a polynomial function that relates albedos to θs was derived and applied to estimate the albedos at 20{\textdegree}. After the removal of θs variations, the observed albedos of grassland at the Konza Prairie showed a linearly decreasing trend from spring to winter due to prairie phenology. The observed albedo of a maize field showed a clear increase from seedling to peak green stage, except when drought caused a decrease in near-infrared reflectance. The observed albedos of a winter wheat field showed an uninterrupted decrease from peak green to harvesting stage.}, keywords = {LTER-KNZ, Agricultural crops, Albedo, phenology, Prairie grassland, Solar zenith angle}, doi = {10.1007/s004840050099}, author = {Song, J.} } @inbook {KNZ00651, title = {Patterns and controls of aboveground net primary production in tallgrass prairie}, booktitle = {Grassland Dynamics: Long-Term Ecological Research in Tallgrass Prairie}, year = {1998}, pages = {193 -221}, publisher = {Oxford University Press}, organization = {Oxford University Press}, address = {New York}, keywords = {LTER-KNZ, tallgrass prairie}, author = {Alan K. Knapp and J. M. Briggs and John M. Blair and Turner, C.L.}, editor = {Alan K. Knapp and J. M. Briggs and D.C. Hartnett and Scott. L. Collins} } @article {KNZ00627, title = {Permutation of two-term local quadrat variance analysis: general concepts for interpretation of peaks}, journal = {Journal of Vegetation Science}, volume = {9}, year = {1998}, pages = {41 -44}, abstract = {Many ecological studies use Two-Term Local Quadrat Variance Analysis (TTLQV) and its derivatives for spatial pattern analysis. Currently, rules for determining variance peak significance are arbitrary. Variance peaks found at block size 1 and at > 50 \% of the transect length are the only peaks whose use is explicitly prohibited. Although the use of variance peaks found at block sizes > 10 \% of the transect length have also been warned against, many researchers interpret them regardless. We show in this paper that variance peaks derived from TTLQV are subject to additional {\textquoteleft}rules of thumb{\textquoteright}. Through the use of randomization and permutation analyses on real and simulated data of species abundance in contiguous plots along a single transect, we show that variance peaks found at block sizes 1, 2 and 3 occur frequently by chance and thus likely do not indicate biologically meaningful patterns. The use of multiple replicate transects decreases the probability of Type II error.}, keywords = {LTER-KNZ, Permutation analysis, Spatial pattern, Variance peak}, doi = {10.2307/3237221}, author = {Campbell, J.E. and Franklin, D.J.G. and Newman, J.A.} } @inbook {KNZ00645, title = {Plant populations: Patterns and processes}, booktitle = {Grassland Dynamics: Long-Term Ecological Research in Tallgrass Prairie}, year = {1998}, pages = {81 -100}, publisher = {Oxford University Press}, organization = {Oxford University Press}, address = {New York}, keywords = {LTER-KNZ, tallgrass prairie}, author = {D.C. Hartnett and Fay, P.A.}, editor = {Alan K. Knapp and J. M. Briggs and D.C. Hartnett and Scott. L. Collins} } @phdthesis {KNZ00630, title = {The pollination biology of the genus penstemon (Scrophulariaceae) in the tallgrass prairie}, volume = {PhD Dissertation}, year = {1998}, school = {Saint Louis University}, type = {Ph.D. Thesis}, address = {Saint Louis, MO}, abstract = {

The pollination ecology of six taxa of prairie species of \<italic\>Penstemon \</italic\> (Scrophulariaceae) was studied on eight sites in Illinois, Kansas and Missouri. These sites span much of the floristic and ecological diversity contained in the tallgrass prairie of the central United States

}, keywords = {LTER-KNZ, tallgrass prairie}, author = {Clinebell, R.R. II.} } @article {KNZ00635, title = {A portable chamber for in situ determination of benthic metabolism}, journal = {Freshwater Biology}, volume = {39}, year = {1998}, pages = {49 -59}, abstract = {1. Many stream ecologists are interested in determining the metabolic rates of benthic organisms, particularly those of production and respiration. It is often necessary to make these measurements on fresh material in the field at remote sites. Recirculating chambers are commonly used for this purpose. 2. A broad variety of recirculating chambers are described in the literature, but each design has inherent limitations. The most common are inability to control flow in the chamber and match it with external flow rates, and a lack of the power required to do this for extended periods. Alteration of spectral irradiance, temperature rise and elevated internal chamber pressures are additional limitations that have received little attention. 3. We have designed and constructed a flow chamber that eliminates some of these problems. The chamber utilizes a DC motor-driven propeller as an efficient recirculator (axial impeller), minimizing power requirements and it is constructed of UVB transparent acrylic to allow a full spectral complement of solar irradiance in the interior. Modular components allow the chamber to be taken apart quickly for cleaning and replacement of parts, making it more functional than some previous designs. 4. The axial impeller chamber was compared to a similar sized conventional chamber that had a small diameter return line and a high capacity centrifugal pump. The axial impeller chamber had less of a temperature rise during field incubations, lower power consumption and less internal pressure in the return line when producing equivalent water velocities. 5. The reported axial impeller design had relatively homogeneous velocity across the working section relative to other chambers and was capable of water velocities in excess of 1 m s{\textendash}1.}, keywords = {LTER-KNZ}, doi = {10.1046/j.1365-2427.1998.00256.x}, author = {W. K. Dodds and Brock, J.} } @article {KNZ00590, title = {Photosynthetic gas exchange and water relations responses of three tallgrass prairie species to elevated carbon dioxide and moderate drought}, journal = {International Journal of Plant Science}, volume = {158}, year = {1997}, pages = {608 -616}, abstract = {Undisturbed tallgrass prairie was exposed to ambient and elevated (twice-ambient) levels of atmospheric CO2 and experimental dry periods. Seasonal and diurnal midday leaf water potential (Ψ leaf), net photosynthesis $(A_{\text{net}})$, and stomatal conductance (g s) responses of three tallgrass prairie growth forms{\textemdash}a C4 grass, Andropogon gerardii; a broad-leaved woody C3 shrub, Symphiocarpos orbiculatus; and a C3 perennial forb, Salvia pitcheri{\textemdash}were assessed. $\Psi _{\text{leaf}}$ in A. gerardii and S. orbiculatus was higher under elevated CO2, regardless of soil moisture, while $\Psi _{\text{leaf}}$ in S. pitcheri responded only to drought. Elevated CO2 always stimulated $A_{\text{net}}$ in the C3 species, while A. gerardii $A_{\text{net}}$ increased only under dry conditions. However, $A_{\text{net}}$ under elevated CO2 in the C3 species declined with drought but not in the C4 grass. Under wet conditions, g s reduced in elevated CO2 for all species. During dry periods, gs at elevated CO2 was sometimes higher than in ambient CO2. Our results support claims that elevated CO2 will stimulate tallgrass prairie productivity during dry periods and possibly reduce temporal and spatial variability in productivity in these grasslands.}, keywords = {LTER-KNZ, Water relations}, url = {http://www.jstor.org/stable/2474921}, author = {Hamerlynck, E.P. and McAllister, C.A. and Alan K. Knapp and J.M. Ham and Owensby, C.E.} } @inbook {KNZ00597, title = {Plant strategies for coping with variable light regimes}, booktitle = {Mechanisms of Environmental Stress Resistance in Plants}, year = {1997}, pages = {191 -212}, publisher = {Harwood Academic Press}, organization = {Harwood Academic Press}, address = {UK}, keywords = {LTER-KNZ}, url = {https://books.google.com/books?hl=en\&lr=\&id=cVUvZePMNfMC\&oi=fnd\&pg=PA191\&dq=\%22Plant\%2Bstrategies\%2Bfor\%2Bcoping\%2Bwith\%2Bvariable\%2Blight\%2Bregimes\%22+Knapp\&ots=4FA7O50id2\&sig=Iyq7j1EZaVkuv5Vkhqg25qu6b5c$\#$v=onepage\&q=\%22Plant\%2Bstrategies\%2Bfor\%2Bcoping\%2}, author = {Alan K. Knapp and Fay, P.A.}, editor = {Basra, A.S. and Basra, R.K.} } @article {KNZ00546, title = {Photosynthetic and stomatal responses to high temperature and light in two oaks at the western limit of their range}, journal = {Tree Physiology}, volume = {16}, year = {1996}, pages = {557 -565}, abstract = {Bur oak (Quercus macrocarpa Michx.) and chinquapin oak (Q. muehlenbergii Engl.) leaves were exposed to high temperatures at various photosynthetic photon flux densities under laboratory conditions to determine if species-specific responses to these factors were consistent with the distribution of these oaks in gallery forests in the tallgrass prairies of northeastern Kansas, USA. Measurements of the ratio of chlorophyll fluorescence decrease, Rfd, indicated that chinquapin oak maintained greater photosynthetic capacity than bur oak across all tested combinations of irradiance (100, 400, 700 and 1000 μmol m-2 s-1) and temperature (40, 42, 44, 46 and 48 {\textdegree}C). In both oak species, manipulation of leaf temperature to about 47 {\textdegree}C for 45 min in the field led to a 45\% decrease in carbon assimilation up to one week after the heat treatment, and to sharp reductions in stomatal conductance. Photosynthetic recovery patterns indicated that bur oak took longer to recover from heat stress than chinquapin oak, suggesting that heat stress may be important in determining distribution patterns of these oak species. Based on a comparison of the results with data from other forest species, we conclude that the photosynthetic temperature tolerances of bur oak and chinquapin oaks facilitate their dominance at the western limit of the eastern deciduous forest.}, keywords = {LTER-KNZ, Chlorophyll fluorescence, heat stress, Quercus macrocarpa, Quercus muehlenbergii}, doi = {10.1093/treephys/16.6.557}, author = {Hamerlynck, E.P. and Alan K. Knapp} } @article {KNZ00539, title = {Photosynthetic and stomatal responses to variable light in a cool-season and warm-season prairie forb}, journal = {International Journal of Plant Science}, volume = {157}, year = {1996}, pages = {303 -308}, abstract = {Species differences in photosynthetic and stomatal responses to steady-state and variable light were examined in two co-occurring tallgrass prairie forbs, the cool-season legume Baptisia bracteata var. glabrescens and the warm-season composite Helianthus annuus. Previous studies indicated that these species might have similar responses to short-term, minutes-long shade because of their similar growth forms. However, photosynthetic carbon gain, oxygen evolution, transpiration, and leaf xylem pressure potential measurements showed that Helianthus was far more responsive than Baptisia to changes in light availability. Helianthus had higher photosynthetic capacity, photosynthetic temperature optimum, stomatal conductance, and transpiration rates, rapid stomatal closure during shade, and delayed photosynthetic recovery when light levels increased, traits common to species exposed to high temperatures or periodic drought stress. Baptisia, active under cooler, wetter conditions than Helianthus, had lower photosynthetic capacity, photosynthetic temperature optimum, stomatal conductance, and transpiration, and no stomatal response to shade, responses typifying species that experience little water stress. We suggest that environmental and physiological factors may combine to reinforce greatly different photosynthetic and stomatal responses to short-term shade in species with similar growth form, especially in habitats with long, seasonally varying growing conditions.}, keywords = {LTER-KNZ}, url = {http://www.jstor.org/stable/2475266}, author = {Fay, P.A. and Alan K. Knapp} } @article {KNZ00540, title = {Plant tolerance of gall-insect attack and gall-insect performance}, journal = {Ecology}, volume = {77}, year = {1996}, pages = {521 -534}, abstract = {We examined plant tolerance of gall{\textemdash}insect attack and gall{\textemdash}insect performance in rosinweed (Silphium integrifolium, Asteraceae) and its apical meristem galler Antistrophus silphii (Hymenoptera: Cynipidae). Gall densities were varied in field rosinweed populations, while gall densities, water, and nutrients were varied for rosinweed in an experimental garden. Field plants grew under prevailing resource and competitive conditions, but garden plants grew free from competition, so gall{\textemdash}insect impacts, rosinweed regrowth, and gall{\textemdash}insect performance were observed under widely different growing conditions. Seasonal measures of rosinweed growth and leaf physiology, and end{\textemdash}of{\textemdash}season measures of biomass, reproduction, gall{\textemdash}wasp emergence, growth, sex ratios, and parasitism were made for both experiments. Rosinweed poorly tolerated Antistrophus gall damage in the field. Galls reduced plant height, leaf area, and inflorescence production. Rosinweed diverted biomass to stems, but produced no regrowth from axillary meristems. In the garden, rosinweed was much more tolerant of Antistrophus gall damage. Galls initially reduced plant height and leaf area, but axillary meristems grew profusely after gall formation, producing nearly all galled plant inflorescences and more than replacing leaf area initially lost to gall formation. Water{\textemdash} and nutrient{\textemdash}supplemented rosinweed were most tolerant of gall damage, experiencing little loss of total biomass or reproductive output. Field rosinweed failed to mount a tolerance{\textemdash}enhancing regrowth response because galls, resource availability, and competition combined to constrain axillary meristem growth. Gall{\textemdash}wasp performance was largely independent of rosinweed tolerance. Emergence, growth, sex ratios, and parasitism were comparable in field and garden, and only slightly affected by resource availability. Gall{\textemdash}insect performance may be buffered from environmental variation, disconnecting plant and herbivore population dynamics. Rosinweed{\textquoteright}s poor tolerance of gall damage may typify forb responses to herbivory in highly competitive grassland plant communities.}, keywords = {LTER-KNZ}, doi = {10.2307/2265627}, author = {Fay, P.A. and D.C. Hartnett and Alan K. Knapp} } @inbook {KNZ00537, title = {Potentially mineralizable N as an indicator of active soil nitrogen}, booktitle = {Methods for Assessing Soil Quality}, year = {1996}, pages = {217 -299}, publisher = {Soil Science Society of America Inc}, organization = {Soil Science Society of America Inc}, address = {Madison, WI}, keywords = {LTER-KNZ}, author = {Drinkwater, L.E. and Cambardella, C.A. and Reeder, J.D. and C. W. Rice}, editor = {Doran, J.W. and Jones, A.J.} } @inbook {KNZ00569, title = {Prairie ecology-the tallgrass prairie}, booktitle = {Prairie Conservation-Preserving North America{\textquoteright}s Most Endangered Ecosystem}, year = {1996}, pages = {39 -52}, publisher = {Island Press}, organization = {Island Press}, address = {Washington, DC}, keywords = {LTER-KNZ, tallgrass prairie}, url = {https://books.google.com/books?hl=en\&lr=\&id=ZlHRjU2EDLQC\&oi=fnd\&pg=PA39\&dq=\%22Prairie\%2Becology-the\%2Btallgrass\%2Bprairie\%22+Steinauer\&ots=7TE04D0yxT\&sig=B4UaGusICyHJqjiwWNTFkCdrE_0$\#$v=onepage\&q=\%22Prairie\%2Becology-the\%2Btallgrass\%2Bprairie\%22\%20Steinauer}, author = {Steinauer, E.M. and Scott. L. Collins}, editor = {Knopf, F.L. and Samson, F.B.} } @article {KNZ00489, title = {Plant productivity and nitrogen gas fluxes in tallgrass prairie}, journal = {Landscape Ecology}, volume = {10}, year = {1995}, pages = {255 -266}, abstract = {We explored relationships between plant productivity and annual fluxes of nitrogen (N2) and nitrous oxide (N2O) in a tallgrass prairie landscape in central Kansas. Our objective was to develop predictive relationships between these variables that could be used in conjunction with remote sensing information on plant productivity to produce large-area estimates of N gas fluxes. Our hypothesis was that there are inherent relationships between plant productivity and N gas fluxes in tallgrass prairie because both are controlled by water and N availability. The research was carried out as part of a multi-investigator project, the First ISLSCP Field Experiment (FIFE, ISLSCP = International Satellite Land Surface Climatology Program), directed toward the use of remote sensing to characterize land-atmosphere interactions. Fluxes of N2 (denitrification) and N2O were measured using soil core techniques. Estimates of annual flux were produced by temporal extrapolation of measured rates. Annual aboveground net primary productivity (ANPP) was estimated from measurements of the maximum standing crop of plant biomass. There were strong relationships between ANPP and N gas fluxes, and between a satellite remote sensing-based index of plant productivity (normalized difference vegetation index, NDVI) and gas fluxes. We used these relationships to convert images of NDVI into images of N gas fluxes for one 83 ha watershed and for the entire 15 by 15 km FIFE site. These images were used to compute mean landscape gas fluxes (0.62 g N m-2 y-1 for N2, 0.66 g N m-2 y-1 for N2O) and total N gas production for the two areas. Our flux and production values are useful for comparison with values produced by simulation models and site-specific studies, and for assessing the significance of N gas production to ecosystem and landscape scale processes related to nutrient cycling, water quality and atmospheric chemistry. }, keywords = {LTER-KNZ, denitrification, NDVI, nitrous oxide, remote sensing}, doi = {10.1007/BF00128993}, author = {Groffman, P.M. and Turner, C.L.} } @proceedings {KNZ00480, title = {Population ecology of Elliot{\textquoteright}s short-tail shrew and least shrew in ungrazed tallgrass prairie}, year = {1995}, pages = {87 -92}, keywords = {LTER-KNZ, tallgrass prairie}, author = {Clark, B.K. and D.W. Kaufman and Kaufman, G.A. and Gurtz, S.K.}, editor = {D.C. Hartnett} } @inbook {KNZ00492, title = {Population Processes}, booktitle = {The Changing Prairie}, year = {1995}, pages = {82 -99}, publisher = {Oxford University Press}, organization = {Oxford University Press}, address = {Oxford}, keywords = {LTER-KNZ}, author = {D.C. Hartnett and Keeler, K.H.}, editor = {Anthony Joern and Keeler, K.K.} } @proceedings {KNZ00505, title = {Prairie voles impact plants in tallgrass prairie}, year = {1995}, pages = {117 -121}, keywords = {LTER-KNZ, tallgrass prairie}, author = {D.W. Kaufman and Bixler, S.H.}, editor = {D.C. Hartnett} } @article {KNZ00475, title = {Prairie voles occur at low density in ungrazed tallgrass prairie in eastern Kansas}, journal = {The Prairie Naturalist}, volume = {27}, year = {1995}, pages = {33 -40}, keywords = {LTER-KNZ, tallgrass prairie}, author = {Bixler, S.H. and D.W. Kaufman} } @mastersthesis {KNZ00519, title = {Protozoa-bacteria interactions in subsurface sediments and the subsequent effects on nitrification}, volume = {MS Thesis}, year = {1995}, pages = {1 -74}, school = {Kansas State University}, type = {M.S. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ}, author = {Strauss, E.A.} } @article {KNZ00445, title = {Plant demographic responses to mycorrhizal symbiosis in tallgrass prairie}, journal = {Oecologia}, volume = {99}, year = {1994}, pages = {21 -26}, abstract = {The effects of mycorrhizal symbiosis on seedling emergence, flowering and densities of several grasses and forbs were assessed in native tallgrass prairie and in sown garden populations at the Konza Prairie in northeastern Kansas. Mycorrhizal activity was experimentally suppressed with the fungicide benomyl. Flowering and stem densities of the cool-season grass, Dichanthelium oligosanthes, sedges (Carex spp.), and the forb Aster ericoides were higher in non-mycorrhizal (benomyl-treated) than in mycorrhizal plots and the magnitude of these differences was significantly affected by burning. Mycorrhizae significantly enhanced flowering of the warmseason grasses Andropogon gerardii and Sorghastrum nutans in burned prairie, but not in unburned sites. These patterns suggest that mycorrhizal effects on the dynamics of cool-season graminoid and forb populations are likely to be mediated indirectly through effects of the symbiosis on the competitive dominance of their neighbors. Seedling emergence rates of the cool-season C3 grasses Elymus canadensis and Koeleria cristata were significantly reduced in the benomyl-treated plots, whereas benomyl treatment had no significant effect on seedling emergence of the warm-season C4 grasses A. gerardii and Panicum virgatum. The forbs showed variable responses. Seedling emergence of Liatris aspera was greater under mycorrhizal conditions, but that of Dalea purpurea was unaffected by mycorrhizal treatment. These results show that effects of mycorrhizal symbiosis on the population dynamics of co-occurring prairie plants vary significantly both among species and among different life history stages within species. The results also indicate that mycorrhizas and fire interact to influence competitive interactions and demographic patterns of tallgrass prairie plant populations.}, keywords = {LTER-KNZ, fire, tallgrass prairie, VA mycorrhizas Plant demography}, doi = {10.1007/BF00317079}, author = {D.C. Hartnett and Samenus, R.H. and Fischer, L.E. and Hetrick, B.A.D.} } @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.} } @article {KNZ00453, title = {Prevalence of hantavirus antibodies in natural populations of deer mice in north central Kansas}, journal = {Prairie Naturalist}, volume = {26}, year = {1994}, pages = {209 -216}, keywords = {LTER-KNZ}, url = {https://www.researchgate.net/publication/258031384_Prevalence_of_Hantavirus_antibodies_in_natural_populations_of_deer_mice_in_north-central_Kansas}, author = {Kaufman, G.A. and D.W. Kaufman and McMillan, B.R. and Brillhart, D.E.} } @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 {KNZ00397, title = {Photosynthetic and stomatal responses of Avena sativa (Poaceae) to a variable light environment}, journal = {American Journal of Botany}, volume = {80}, year = {1993}, pages = {1369 -1373}, abstract = {The net photosynthetic (A), stomatal conductance to water vapor (g), water use efficiency (WUE = A/transpiration), and leaf water potential (Ψ) responses of cultivated oats (Avena sativa) were determined under an experimental regime of alternating full sun (photosynthetic photon flux density, PPFD > 1,700 μmol{\textperiodcentered}m-2{\textperiodcentered}sec-1) and shade (300-400 μmol{\textperiodcentered}m-2 sec-1 PPFD). Less extensive measurements were made on winter wheat (Triticum aestivum) to test the generality of crop species{\textquoteright} responses. The rates of stomatal opening/closing after changes in PPFD in Avena and Triticum were compared with previously determined rates for native grasses and forbs to assess how domestication might have altered stomatal dynamics. Characteristics of Avena under alternating sun and shade were 1) rapid fluctuations in A between full sun (\~{}27 μmol{\textperiodcentered}m-2 sec-1) and shade rates (\~{}12-13 μmol m-2{\textperiodcentered}sec-1); 2) slower changes in g, causing progressive stomatal closure during the measurement sequence and possible stomatal limitation of A; 3) no change in leaf Ψ; and 4) a net reduction in WUE. Triticum had similar sun/shade A, g, and WUE dynamics, except that Triticum stomata returned to full-sun g between shade periods. The rates of change of g in Avena and Triticum were lower than for some desert and subalpine native species, but were similar to rates for species in adjoining native habitat. The basic stomatal dynamics of Avena and Triticum may typify many cultivated C3 species, and these data indicate that crop stomatal behavior has not diverged significantly from that of native species.}, keywords = {LTER-KNZ}, url = {http://www.jstor.org/stable/2445664}, author = {Fay, P.A. and Alan K. Knapp} } @article {KNZ00414, title = {Preliminary assessment of nitrate at two sites in Kansas-comparison of alluvial aquifer and fractured limestone, Kansas Water Resources Research Institute Report, Contribution No. 305}, year = {1993}, pages = {39 -}, keywords = {LTER-KNZ}, author = {G. L. Macpherson} } @article {KNZ00364, title = {Partitioning of dissolved inorganic or organic phosphorus using acidified molybdate and isobutanol}, journal = {Soil Science Society of American Journal}, volume = {56}, year = {1992}, pages = {762 -765}, keywords = {LTER-KNZ}, doi = {10.2136/sssaj1992.03615995005600030014x}, author = {Jayachandran, K. and Schwab, A.P. and Hetrick, B.A.D.} } @proceedings {KNZ00350, title = {Population ecology of thirteen-lined ground squirrels in ungrazed tallgrass prairie manipulated by fire}, year = {1992}, pages = {51 -54}, address = {University of Northern Iowa}, abstract = {

From March 1983 to October 1987, thirteen-lined ground squirrels (Spermophilus tridecemlineatus Mitchill) were studied in ungrazed tallgrass prairie manipulated by fire on the Konza Prairie Research Natural Area, Kansas. Overall abundance varied among years (2.6 animals/ha in 1985; 5.6 animals/ha in 1986); however, no significant variation in sex ratio was observed (overall average=52\% males for adults, 48\% males for juveniles). Fire had a positive effect on ground squirrels; abundance was significantly higher in burned than unburned prairie during the year of a fire and in more recently than less recently burned prairie during years following a fire. Ground squirrels also selected hillsides with exposed rocks (breaks) over upland and lowland prairie sites. Although females and males selected similar habitats, home ranges were significantly larger for adult males (average=0.56 ha) than for adult females (0.36 ha). Both adult females and males caught on the study area typically were residents rather than transients. Further, overwinter survival did not differ between adult females and males. Overwinter survival of juvenile females was similar to adults; however, no juvenile males overwintered on the study area

}, keywords = {LTER-KNZ, tallgrass prairie}, author = {Clark, B.K. and D.W. Kaufman and Kaufman, G.A. and Gurtz, S.K. and Bixler, S.H.}, editor = {Smith, D.A. and Jacobs, C.A.} } @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 {KNZ00279, title = {Patch structure in tallgrass prairies: dynamics of satellite species}, journal = {Oikos}, volume = {57}, year = {1990}, pages = {229 -236}, abstract = {

Space in tallgrass prairie communities is dominated by a few core species. A large number of less abundant, satellite species occupy the remaining space. These satellite species define vegetation patches that vary withinn and between growing seasons. In order to determine if patch structure was random we established five permanent 100-m2 blocks in undisturbed tallgrass prairie in Oklahoma and Kansas. Presence of core and satellite species in each m2 was sampled over one or two growing seasons. Patch types were defined by cluster analysis. Characteristics of patch structure included number of patch types, patch type diversity, patch composition, number of spatial groups, group size, and fractal dimension of the spatial groups. We generated simulated data sets with random species associations, in which we quantified patch structure. Actual patch structure, defined mainly by satellite species, was not significanly different from simulated patch structure, except that simulated patches were more fragmented. Therefore, processes that affect species associations may not be important controls of patch structure of satellite species within the spatial and temporal scale of this analysis. Because there was some degree of spatial autocorrelation in patch structure, dispersal processes may have significant effects on patch structure at this scale. In order to understand grassland community dynamics, we propose that satellite species should be modelled using stochastic models constrained by core species dynamics. This approach may be applicable to any community with major components operating at different hierarchical levels

}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.2307/3565944}, author = {Glenn, S.M. and Scott. L. Collins} } @article {KNZ00298, title = {Patterns and controls of nitrogen in tallgrass prairie streams}, journal = {Ecology}, volume = {71}, year = {1990}, pages = {2007 -2018}, abstract = {

A descriptive and experimental approach was used to study patterns of nitrogen concentrations in tallgrass prairie streams in Kansas. Nitrate concentrations varied depending on the year, season, time of day, stream flow conditions, source of water, and location where the sample was taken. Mean nitrate concentrations during the dormant season decreased from 1982 to 1984, corresponding to above normal precipitation during this same period. Nitrate concentrations decreased from third-order (grass/shrub riparian vegetation) to fourth-order channels (gallery forests). Nitrate, organic N, and total N were higher in a third-order intermittent stream than in a third-order perennial stream. Water from seeps and tributaries had higher nitrate concentrations than stream water; however, streams and tributaries had higher organic N than seeps. Maximum nitrate concentrations during storm flows were directly related to the magnitude of storms and inversely related to the frequency of storm events. The activity of terrestrial vegetation influenced nitrate concentrations within streams, seeps, and tributaries; nitrate concentrations were always higher during periods of vegetation dormancy. Aquatic biota influenced both spatial patterns (downstream decrease in nitrate concentrations and increase in organic N) and diel patterns of nitrate concentration (night greater than day). Uptake rates of nitrate by biota were greater during the day than during the night as determined by experimental addition of nitrate. Nitrogen (N) and/or phosphorus (P) limitations of algal growth were tested experimentally using nutrient- diffusing substrata (clay saucers filled with enriched agar) and enrichment of artificial channels. Addition of N and P in combination increased algal biomass (chlorophyll a and ash-free dry mass) over controls or single addition of N or P. Thus, algal biomass was N and P limited; however, individual taxa responded to specific N and/or P concentrations or atomic N:P ratio. Key words: flooding, intermittent stream, nitrate, nitrogen, nutrient limitation, organic nitrogen, periphyton, phosphorus, tallgrass prairie, stream

}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {http://www.jstor.org/stable/1937609}, author = {Tate, C.M.} } @phdthesis {KNZ00288, title = {Population ecology, social organization, and mating systems in the deer mouse (Peromyscus maniculatus bairdii) in mixed-grass prairie in Kansas}, volume = {PhD Dissertation}, year = {1990}, pages = {1 -187}, school = {Kansas State University}, type = {Ph.D. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ}, author = {Kaufman, G.A.} } @article {KNZ00266, title = {Prevalence of botfly (Cuterebra sp.) parasites in populations of small mammals in eastern Kansas}, journal = {The American Midland Naturalist}, volume = {124}, year = {1990}, pages = {22 -30}, abstract = {

Prevalence of botfly (Cuterebra sp.) parasitism in populations of small mammals was studied in tallgrass prairie of northeastern Kansas during 1985-1987. Four species of rodents, Neotoma floridana, Peromyscus leucopus, P. maniculatus, and Reithrodontymys megalotis, were parasitized and all infestations occurred between 1 June and 30 September. Prevalence was greatest in July and August of all species. Proportions of N. floridana (0.31) and P. leucopus (0.24) parasitized were similar and significantly greater than those of P. maniculatus (0.08) and R. megalotis (0.02). Over 95\% of the parasitized animals were adults with no differences noted due to sex. Parasitized individuals resided longer on the study area than unparasitized animals for N. floridana, P. leucopus and R. megalotis, but not P. maniculatus. The relationship between residence time and parasitism, as well as higher proportions of infestation for N. floridana and P. leucopus, probably due to overlap in preferred habitat (woody vegetation in ravines and contiguous lowlands) between adult Cuterebra and these rodents

}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.2307/2426076}, author = {Clark, B.K. and D.W. Kaufman} } @article {KNZ00262, title = {Passerine breeding birds of Konza Prairie}, journal = {Kansas Ornithology Society Bulletin}, volume = {40}, year = {1989}, pages = {23 -28}, abstract = {

This paper provides a current listing of passerine species with documented breeding records. Eastern Wood-Pewee (Contopus virens), Eastern Phoebe (Sayornis phoebe, Great crested flycatcher (Myiarchus crinitus), Eastern kingbird (Tyrannus tyrannus), Scissor-tailed flycatcher (Tyrannus forficatus), Horned lark (Eremophila alpestris), Northern rough-winged swallow (Stelgidopteryx serripennis), Barn swallow (Hirundo rustica), Blue jay (Cyanocitta cristata), Black-capped chickadee (Parus atricapillus), Tufted titmouse (Parus bicolor), White-breasted nuthatch (Sitta carolinensis), Bewick\&$\#$39;s wren (Thryomanes bewickii), House wren (Troglodytes aedon), Sedge wren (Cistothorus platensis), Blue-gray gnatcatcher (Polioptilla caerulea), Eastern bluebird (Sialis sialis), American robin (Turdus migratorius), Gray catbird (Dumetella carolinensis), Brown thrasher (Toxostoma rufum), Loggerhead shrike (Lanius ludovicianus), Starling (Sturnus vulgaris), Bell\&$\#$39;s vireo (Vireo bellii), Louisiana waterthrush (Seiurus motacilla), Common yellowthroat (Geothlypis trichas), Northern cardinal (Cardinalis cardinalis), Indigo bunting (Passerina cyanea), Dickcissel (Spiza americana), Rufous-sided towhee (Pipilo erythrophthalmus), Field sparrow (Spizella pusilla), Grasshopper sparrow (Ammodramus savannarum), Henslow\&$\#$39;s sparrow (Ammocramus henslowii)Red-winged blackbird (Agelaius phoeniceus), Eastern meadowlark (Sturnella magna), Common grackle (Quiscalus quisula), Brown-headed cowbird (Molothrus ater), Orchard oriole (Icterus spurius), Northern oriole (Icterus galbula), American goldfinch (Carduelis tristis), House sparrow (Passer domesticus). The following passerines probably nest on Konza Prairie, but no direct evidence of breeding has been obtained: American Crow, Carolina Wren, Warbling Vireo, Red-eyed Vireo, Black-and-White Warbler, Kentucky Warbler, Summer Tanager, Scarlet Tanager, Rose-breasted Grosbeak, Blue Grosbeak, Lark Sparrow

}, keywords = {LTER-KNZ}, author = {Zimmerman, J.L.} } @proceedings {KNZ00242, title = {Polyploid polymorphism in the prairie grass big bluestem (Andropogon gerardii)}, year = {1989}, publisher = {University of Nebraska Press}, address = {Lincoln, NE}, abstract = {

A suprising number of plant species contain individuals of a variety of levels of polyploidy, so that the species is polymorphic for polyploidy. This paper considers possible general causes for this phenomenon in plants of the Great Plains of North America. First we compared the frequency of intraspecific polyploidy in three major plant families, Poaceae, Asteraceae, and Fabaceae. The majority of grass species (Poaceae) and the minority of composite and legume species (Asteraceae and Fabaceae) are polyploid polymorphic. The frequency of grass species with intraspecific polyploidy suggests shared causatin or at least shared tolerance of this character. Having established that the situation occurs frequently in grasses, we analyzed a single species, big bluestem, Andropogon gerardii, looking for information on the function of polyploid polymorphism. We used flow cytometry to determine amount of nuclear DNA per cell; In big bluestem this correlates with chromosome number. Individuals with 7 pg nuclear DNA had 2N=60 chromosomes, and were therefore hexaploid, since in Andropogon x=10. Most other individuals had approximately 10 pg nuclear DNA and 80 (occasionally 90) chromosomes. Seven-pg DNA individuals were predominatnt everywhere, but the frequency of higher polyploids (10 pg nuclear DNA) went from virtually 0 on the eastern end of the tallgrass prairie region to 40\% at the western end. Within native prairies in the west, the full range of variation existed between sites. A recent origin for polyploid polymorphism is suggested in big bluestem and probably other Great Plains grasses, and the data seem most compatible with a transitional situation, although other explanations cannot be ruled out

}, keywords = {LTER-KNZ}, author = {Keeler, K.H. and Kwankin, B.}, editor = {Bragg, T.B. and Stubbendieck, J.} } @inbook {KNZ00239, title = {Population biology}, booktitle = {Advances in the Study of Peromyscus (Rodentia)}, year = {1989}, pages = {233 -270}, publisher = {Texas Tech University Press}, organization = {Texas Tech University Press}, address = {Lubbock,TX}, abstract = {

Recent literature on Peromyscus encompasses both descriptive and experimental studies that have led to new insights in population ecology, behavioral ecology, and community ecology. Genetic variation has been assessed in over 20 species of Peromyscus, with several studies focused on understanding patterns of macrogeographic differntiation, including island effects. Detailed analyses of the dynamics of microgeographic genetic structure are needed to better understand the organization and dynamics of populations. Additionally, little is known about the adaptive significance of biochemical variation. Social interactions in populations of Peromyscus are being examined in greater detail than before and are potentially important to the study of population regulation. Advances in understanding microhabitat selection and distribution, mostly involving P. leucopus and P. maniculatus, have been accomplished through use of multivariate statistical techniques and to lesser degree experimental manipulations. A major part of the increased effort in microhabitat analysis of Peromyscus species has been the result of studies of interspecific microhabitat partitioning. However, integrated studies of habitat selection, foraging, interspecific competition, and differential risk of predation are needed to better assess and describe interspecific resource partitioning within assemblages and the influence of age and sex on intraspecific resource partitioning. Ecological limits to population size, organization of populations, sex ratios, foraging behavior, and predation risk are less studied in Peromyscus, although some interesting observations have been made

}, keywords = {LTER-KNZ}, author = {D.W. Kaufman and Kaufman, G.A.}, editor = {Kirkland, G.L. and Layne, J.N.} } @article {KNZ00254, title = {Preliminary modelling of transpiration from the FIFE site in Kansas}, journal = {Agricultural and Forest Meterology}, volume = {48}, year = {1989}, pages = {305 -315}, keywords = {LTER-KNZ}, doi = {10.1016/0168-1923(89)90075-0}, author = {Stewart, J.B. and Gray, L.W.} } @article {KNZ00181, title = {Physical and topological assessment of vesicular-arbuscular mycorrhizal fungus on root architecture of big bluestem}, journal = {New Phytologist}, volume = {110}, year = {1988}, pages = {85 -96}, abstract = {

The influence of vesicular-arbuscular (VA) mycorrhizal fungus, phosphorus (P) fertilization, and soil microorganisms on growth and root architecture of big bluestem (Andropogon gerardii Vitman) was investigated. In pasteurized soil, mycorrhizal inoculation significantly improved plant growth and increased root length and the number and the diameter of the primary, secondary and tertiary roots. These differences between mycorrhizal and non-mycorrhizal plants diminished with added P. In pasteurized soil amended with non-sterile soil sievate, differences between mycorrhizal and non-mycorrhizal plants were still obvious, but in may treatments these plants grew more poorly (had less dry weight, root length, number or diameter) than their counterparts in unamended pasteurized soil. Growth in non-sterile soil was also suppressed, and mycorrhizal responses were not detected since all of the plants in non-sterile soil became mycorrhizal whether or not they were inoculated. Two analyses of calculated parameters which describe root- system architecture were conducted. The first, specific root length (SRL), revealed that mycorrhizal symbiosis dramatically alters root morphology in soils of low fertility. These changes were similar to the changes evoked by added P. The second, path length (Pe) revealed that mycorrhizal fungi (and to some degree other soil microbes) significantly alter root architecture by reducing the relative amount of root branching. Apparently, mycorrhizal plants develop a more elongate, exploratory growth pattern which permits the fungal hyphae to extract nutrients from a larger volume of soil. In contract roots of non-mycorrhizal plants maintain a more highly branched pattern of root growth, and the roots themselves play a more critical role in the direct extraction of nutrients from the soil. These differences in root topology were not directly associated with the concentration of exogenous P, but instead appeared to be controlled by the mycorrhizal fungi themselves. Thus, while internal P content of plants mediates the establishment of the mycorrhizal symbiosis, the fungi can alter the root architecture of the plant to a form which best accommodates the symbiosis under the prevailing fertility and rhizosphere conditions in the soil. By altering root-system architecture in this manner, the mycorrhizal fungi can control, at least to some degree, the dependence of the host on the symbiosis. Thus, the topology of the root system is contingent upon the microflora in the rhizosphere. The topological analysis revealed differences in root architecture not detected by any of the other measures of root morphology. These differences suggest that mycorrhizal fungi affect root architecture and plant growth in ways not directly associated with phosphorus uptake. Key words: path length, phosphorus, root morphology, specific root length

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1469-8137.1988.tb00240.x}, author = {Hetrick, B.A.D. and Leslie, J.F. and G.T. Wilson and Kitt, D.G.} } @article {KNZ00188, title = {The postfire environment and earthworm populations in tallgrass prairie}, journal = {Ecology}, volume = {69}, year = {1988}, pages = {476 -483}, abstract = {

Burning of tallgrass prairie is hypothesized to have positive effects on the resource base for belowground-feeding earthworms, but negative effects on the suitability of the soil climate for earthworms. To a certain extent these are inseparable due to the physiology of the grasses that dominate the ecosystem. A four- by-two factorial design using spring burning, autumn burning, addition of natural mulch, and control, with irrigation and without, was used to partially separate the different effects of burning on earthworm populations and to analyze the mechanisms of the responses. The biomass of native prairie earthworms Diplocardia smithii and D. verrucosa increased 135 and 67\%, respectively, with burning; the former species was unaffected by irrigation, and the latter was positively affected. Biomass of an introduced European species Aporrectodea turgida declined from 1.3 g/m2 on unburned plots to 0.85 g/m2 on burned plots and increased with irrigation. These responses reflect increases in the resource base on burned plots, as indicated by an 11\% increase in soil organic matter, and different physiological requirements of the three species. Key words: Aporrectodea, Diplocardia, earthworms, fire, irrigation, soil climate, soil organic matter, tallgrass prairie

}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.2307/1940446}, author = {James, S.W.} } @article {KNZ00104, title = {Physiological plasticity in water relations and leaf structure of understory versus open-grown Cercis canadensis in northeastern Kansas}, journal = {Canadian Journal of Forestry Resources}, volume = {16}, year = {1986}, pages = {1170 -1174}, abstract = {

Field and laboratory studies were used to evaluate physiological plasticity in water relations and leaf structural characteristics of Cercis canadensis L. (redbud) saplings growing in a gallery forest understory and an adjacent prairie in eastern Kansas. Two study periods were defined based on high (greater than -0.2 MPa in May) and low (-1.5 MPa in July) predawn soil water potential ( soil) Leaf conductance to water vapor diffusion (gwv) was greater for prairie than understory redbud saplings during both sampling periods (maximum gwv=7.5-8.7 mm s-1) Moreover, gwv for prairie redbud remained high at both high and low soil, but was significantly lower for understory redbud during midday at low soil. Transpiration flux was also higher in the prairie than in the understory site and reach a maximum for prairie redbud (318 mg m-2s-1) in July, in conjunction with high leaf to air vapor pressure deficits (maximum 5.3 kPa). Leaf water potential declined significantly at both sites with decreased soil and the minimum values (-3.0 MPa) were recorded in understory redbud. Leaves of prairie redbud were significantly smaller, thicker, and had higher specific leaf mass and stomatal density than leaves of understory redbud, which are consistent with differences between zeric and mesic species, respectively. These differences in water relations and leaf morphology between understory and prairie redbud suggest a high degree of physiological plasticity for this species in eastern Kansas

}, keywords = {LTER-KNZ, Water relations}, doi = {10.1139/x86-208}, author = {Abrams, M.D.} } @article {KNZ00118, title = {Postfire water relations, production, and biomass allocation in the shrub, Rhus glabra, in tallgrass prairie}, journal = {Botanical Gazette}, volume = {147}, year = {1986}, pages = {90 -97}, abstract = {

Several populations of Rhus glabra were studies to assess the effect of fire on productivity, biomass allocation, N and chlorophyll content, and seasonal water relations in a North American tallgrass prairie. Compared with shoots in unburned prairie, shoots from burned sites had reduced biomass and fewer leaves; however, a significant postfire increase in shoot density led to similar midseason leaf area indices for both populations. Productivity was greater in the unburned population principally because of the biomass of sexual reproductive structures, which were absent in the resprouting shoots. However, burned populations allocated a greater proportion of biomass to leaves and wood, utilized for vertical growth, than unburned populations. Leaves in unburned prairie had greater stomatal density, specific leaf mass, and chlorophyll and N content than leaves from the burned population. For much of the growing season, stomatal conductances were greater in unburned prairie. Despite lower soil water potentials at the burned site, differences in midday leaf water potentials were small between populations; hence, differences in N content probably contributed more to the responses. The postfire reduction in productivity and sexual reproduction in R. glabra indicates that fire reduces its fitness

}, keywords = {LTER-KNZ, Water relations}, doi = {http://www.jstor.org/stable/2474813}, author = {Alan K. Knapp} } @article {KNZ00120, title = {Production, density and height of flower stalks of three grasses in annually burned and unburned eastern Kansas tallgrass prairie: a four year record}, journal = {The Southwestern Naturalist}, volume = {31}, year = {1986}, pages = {235 -241}, abstract = {

The production, density and height of flower stalks of Andropogon gerardii, Schizachrium scoparium and Sorghastrum nutans were surveyed over a four-year period (1981-1984) on burned vs unburned and shallow vs deep soil sites in native, undisturbed tallgrass prairie. In general, flower stalk height was greater on deep than the shallow soils but the response of height to fire was variable. In contrast, density and production of flower stalks were usually greater on the annualy burned sites, whereas soil effects were inconsistent. Production of flower stalks for all three species combined ranged from 0 to 670 g/m2 during the 4-year period with maximum production occurring in a mesic year which followed a drought year

}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.2307/3670564}, author = {Alan K. Knapp and Hulbert, L.C.} } @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 {KNZ0065, title = {Postburn differences in solar radiation, leaf temperature, and water stress influencing production in a lowland tallgrass prairie}, journal = {American Journal of Botany}, volume = {71}, year = {1984}, pages = {220 -227}, abstract = {

The influence of standing dead biomass on available solar radiation, leaf temperature and leaf water potential of Andropogon gerardii in unburned tallgrass prairie was compared to burned prairie in eastern Kansas. The standing dead reduced photosynthetically active radiation incident on emerging shoots by 58.8\% in unburned compared to burned prairie during the initial 30 days of the growing season. Aboveground production in unburned prairie was similarly reduced during this period (55.4\%) compared to burned prairie. Leaf temperatures in A. gerardii were greater in unburned prairie than in burned early in the season, but were nearly equal by the end of the growing season. The maximum elevation of leaf temperature in unburned prairie above burned was 9.5 C. The maximum unburned leaf temperature measured was 41.5 C compared to 39.4 C in burned prairie. Lower windspeed adjacent to leaves in unburned prairie resulting in reduced convective cooling may have caused higher leaf temperature in unburned prairie. Leaf water potential was significantly lower in unburned prairie than in burned prairie early in the season but was higher in unburned prairie by late season. The seasonal minimum leaf water potential in burned prairie was -1.60 MPa compared to -1.45 MPa in unburned prairie. The combined effect of these post-burn differences in solar radiation, leaf temperature and leaf water potential may be significant in contributing to the lower production in unburned compared to burned tallgrass prairie

}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {http://www.jstor.org/stable/2443749}, author = {Alan K. Knapp} } @article {KNZ0059, title = {Preferences and influence of paired food items on energy intake of American robins and gray catbirds}, journal = {Journal of Wildlife Management}, volume = {48}, year = {1984}, pages = {198 -202}, abstract = {

Seed selection by avian granivores has been studied intensively in laboratories, but comparable studies have not been reported for frugivores. Kantak (1979) and Baird (1980) both postulate that conspicuous color may play a more important role in food selection by frugivores than the size or nutritional quality of the fruit. Knowledge of fruit preferences may increase the effectiveness of habitat improvement programs designed to benefit frugivorous birds. We conducted a study using two frugivorous birds, American robins (Turdus migratorius) and gray catbirds (Dumetella carolinensis), to provide data on food selection by frugivores in Kansas

}, keywords = {LTER-KNZ, bird, diet, foot}, doi = {10.2307/3808471}, author = {Hazelton, P.K. and Robel, R.J.} } @article {KNZ0025, title = {Predation on red-winged blackbird eggs and nestlings}, journal = {The Wilson Bulletin}, volume = {91}, year = {1979}, pages = {426 -433}, abstract = {

The contents of red-winged Blackbird (Agelaius phoeniceus) nests are subject to extensive and highly variable losses. Normally, most red-wing eggs fail to produce young that are able to leave the nest. Most researchers have found 60 to 100\% of the losses to be due to predation on nest contents, where the entire brood or clutch is lost at once. Fewer than 5\% of the losses normally appear to be related to starvation of nestlings or nestling competition. The remainder of the losses (under 40\%) result from a variety of causes, including egg infertility, nest desertion, and nest tipping due to growth of the supporting vegetation. In this study, I relate predatory losses of red-wing nestlings and eggs to water depth at nest-sites, habitat type, and number of young in the nest. My studies were done in east-central Kansas; several previous authors have presented data from similar studies in other parts of the range of the Red-winged Blackbird

}, keywords = {LTER-KNZ, blackbird, predation}, url = {http://www.jstor.org/stable/4161244}, author = {Shipley, F.S.} }