@article {6200, title = {Clarifying the effect of biodiversity on productivity in natural ecosystems with longitudinal data and new methods for causal inference}, journal = {Nature Communications}, year = {In Press}, keywords = {LTER-KNZ}, author = {Dee, L.E. and Ferraro, P.J. and Severen, C. and Kimmel, K. and Borer, E.T. and Byrnes, J.E.K. and Clark, A. and Hautier, Y. and Hector, A. and Raynaud, X. and Reich, P.B. and Wright, A. and Arnillas, C.A. and Davies, K.F. and MacDougall, A.S. and Mori, A. and Smith, M.D. and Adler, P.B. and Bakker, J.D. and Braumann, K. and Cowles, J.M. and Komatsu, K.J. and Knops, J. and McCulley, R. and Moore, J.L. and Morgan, J.W. and Ohlert, T. and Power, S.A. and Sullivan, L. and Stevens, C. and Loreau, M.} } @article {6291, title = {Changes in water age during dry-down of a non-perennial stream}, journal = {Water Resources Research}, volume = {60}, year = {2024}, pages = {e2023WR034623}, keywords = {LTER-KNZ}, doi = {10.1029/2023WR034623}, url = {https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023WR034623}, author = {Swenson, Logan J. and Zipper, Sam and Peterson, Delaney M. and Jones, C. Nathan and Burgin, Amy J. and Seybold, Erin and Kirk, Matthew F. and Hatley, Camden} } @article {6238, title = {Compositional variation in grassland plant communities}, journal = {Ecosphere}, volume = {14}, year = {2023}, pages = {e4542}, keywords = {LTER-KNZ}, doi = {10.1002/ecs2.v14.610.1002/ecs2.4542}, url = {https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecs2.4542}, author = {Bakker, Jonathan D. and Price, Jodi N. and Henning, Jeremiah A. and Batzer, Evan E. and Ohlert, Timothy J. and Wainwright, Claire E. and Adler, Peter B. and Alberti, Juan and Arnillas, Carlos Alberto and Biederman, Lori A. and Borer, Elizabeth T. and Brudvig, Lars A. and Buckley, Yvonne M. and Bugalho, Miguel N. and Cadotte, Marc W. and Caldeira, Maria C. and Catford, Jane A. and Chen, Qingqing and Crawley, Michael J. and Daleo, Pedro and Dickman, Chris R. and Donohue, Ian and DuPre, Mary Ellyn and Ebeling, Anne and Eisenhauer, Nico and Fay, Philip A. and Gruner, Daniel S. and Haider, Sylvia and Hautier, Yann and Jentsch, Anke and Kirkman, Kevin and Knops, Johannes M. H. and Lannes, Lu{\'\i}ola S. and MacDougall, Andrew S. and McCulley, Rebecca L. and Mitchell, Rachel M. and Moore, Joslin L. and Morgan, John W. and Mortensen, Brent and Olde Venterink, Harry and Peri, Pablo L. and Power, Sally A. and Prober, Suzanne M. and Roscher, Christiane and Sankaran, Mahesh and Seabloom, Eric W. and M. D. Smith and Stevens, Carly and Sullivan, Lauren L. and Tedder, Michelle and Veen, G. F. (Ciska) and Virtanen, Risto and Wardle, Glenda M.} } @article {6153, title = {Contrasting intra-annual population dynamics of two codominant species are consistent across spatial and temporal scales}, journal = {Journal of Ecology}, volume = {111}, year = {2023}, pages = {676-686}, keywords = {LTER-KNZ}, doi = {10.1111/1365-2745.14055}, url = {https://besjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1365-2745.14055}, author = {Gray, Jesse E. and M. D. Smith} } @inbook {6053, title = {Climate change in grassland ecosystems: current impacts and potential actions for a sustainable future}, booktitle = {CLIMATE ACTIONS - LOCAL APPLICATIONS AND PRACTICAL SOLUTIONS}, year = {2022}, pages = {36}, publisher = {CRC}, organization = {CRC}, edition = {1}, abstract = {

Grasslands are a widespread and globally important biome providing key ecosystem services, including carbon storage, regulation of the water cycle and diverse assemblages of plant and animal species. Grasslands also provide many important benefits to humans, such as food and forage for livestock. Climate changes manifest as temperature fluctuations, increased intensity of drought and flood cycles and increased atmospheric CO2 concentrations. These changes are impacting species growth responses, plant composition and other key grassland processes. In addition to the direct consequences of climate change, secondary (or indirect) impacts of climate change threaten grassland ecosystems. These include changes in land-use and land-cover, agricultural conversion, woody encroachment, invasive species and atmospheric nitrogen deposition. In this chapter, we discuss the direct and indirect impacts of climate change on grasslands generally, while using case studies from specific global grassland types to illustrate key threats and climate change impacts. We specifically provide examples of how direct and indirect climate changes interact, increasing the vulnerability of grasslands. In the final section of this chapter, we outline a climate action plan for grassland ecosystems that includes efforts focused at multiple scales, including the individual, community and global levels. These climate actions can be used to influence policy, reduce the rate of climate change, conserve and restore grasslands and, most importantly, need to begin immediately. Collectively, we explain the general ecological processes in grasslands, illustrate the consequences of climate change on this ecosystem and identify potential solutions to maintain the viability and persistence of grassland ecosystems for the foreseeable future.

}, keywords = {LTER-KNZ}, isbn = {9780367478339}, author = {Jesse B. Nippert and Keen, R.M. and Bachle, Seton and Wedel, E.R. and B. Groskinsky} } @phdthesis {6048, title = {Climate legacies and restoration history as drivers of tallgrass prairie carbon and nitrogen cycling}, volume = {PhD Dissertation}, year = {2022}, school = {Kansas State University}, type = {Ph.D. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ, carbon cycling, Climate legacies, Nitrogen cycling, restoration, tallgrass prairie}, url = {https://krex.k-state.edu/dspace/handle/2097/42101}, author = {Broderick, C.M.} } @article {6022, title = {Climate legacies determine grassland responses to future rainfall regimes}, journal = {Global Change Biology}, volume = {28}, year = {2022}, pages = {2639-2656}, keywords = {LTER-KNZ}, doi = {10.1111/gcb.16084}, url = {https://onlinelibrary.wiley.com/doi/10.1111/gcb.16084}, author = {Broderick, C.M. and Wilkins, K. and M. D. Smith and J. M. Blair} } @article {6127, title = {Climate legacy effects shape tallgrass prairie nitrogen cycling}, journal = {Journal of Geophysical Research: Biogeosciences}, volume = {127}, year = {2022}, pages = {e2022JG006972}, keywords = {LTER-KNZ}, issn = {2169-8953}, doi = {10.1029/2022JG006972}, url = {https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022JG006972?af=R}, author = {Broderick, C.M. and Freeman, Kiona M. and L.H. Zeglin and J. M. Blair} } @article {6021, title = {Climate variability supersedes grazing to determine the anatomy and physiology of a dominant grassland species}, journal = {Oecologia}, volume = {198}, year = {2022}, pages = {345{\textendash}355}, keywords = {LTER-KNZ}, issn = {0029-8549}, doi = {10.1007/s00442-022-05106-x}, url = {https://link.springer.com/10.1007/s00442-022-05106-x}, author = {Bachle, Seton. and Nippert, J.B.} } @mastersthesis {6129, title = {Comparative phylogeography of small mammals across the Great Plains Suture Zone highlights repeated processes of speciation and community assembly coincident with the 100th meridian}, volume = {MS Thesis}, year = {2022}, school = {Kansas State University}, type = {M.S. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ}, url = {https://krex.k-state.edu/dspace/handle/2097/42395}, author = {Herrera, Thomas} } @article {6128, title = { Cross-site comparisons of climate change on drylands in the US Long-term Ecological Research network}, journal = {BioScience}, volume = {72}, year = {2022}, pages = {889 - 907}, keywords = {LTER-KNZ}, doi = {10.1093/biosci/biab134}, url = {https://academic.oup.com/bioscience/article/72/9/889/6654840}, author = {Hudson, Amy R and Peters, D.P.C. and J. M. Blair and Childers, Daniel L and Doran, Peter T and Geil, Kerrie and Gooseff, Michael and Gross, Katherine L and Haddad, Nick M and Pastore, Melissa A and Rudgers, Jennifer A and Sala, Osvaldo and Seabloom, Eric W and Shaver, Gaius} } @mastersthesis {6130, title = {A conservation and taxonomic assessment of the least shrew (Cryptotis parvus) complex through rangewide phylogeographic analyses and population genomics}, volume = {MS Thesis}, year = {2021}, school = { Kansas State University}, type = {M.S. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ}, url = {https://krex.k-state.edu/dspace/handle/2097/41785}, author = {Galfano, Thomas.} } @article {KNZ002047, title = {Consumer roles of small mammals within fragmented native tallgrass prairie}, journal = {Ecosphere}, volume = {12}, year = {2021}, pages = {e03441}, abstract = {

Grassland ecosystems globally are being negatively impacted by changes in climate, disturbance regimes, nutrient flux, and consumer guilds. Changes in the trophic ecology of consumers can substantially influence local resources, contributing to shifting diversity, community turnover, and other processes of ecosystem change. Small mammals are diverse and abundant within grasslands and yet the impact of changing ecosystems on small mammals and the role of these mammals as consumers are still both under-studied. We assessed small mammal resource use within grassland and woodland vegetation types that have resulted from landscape-scale experimental disturbance through fire treatments within the tallgrass prairie ecoregion of the North American Great Plains. We predicted that resource use would vary significantly among grassland vs. woodland communities, in turn reducing the role of small mammals in contributing to future maintenance of native prairies. We sampled five dominant species of rodents across three years and multiple habitats. Using stable isotope analysis, we investigated isotopic niche area and overlap to infer variation in diet, both within and among species. Resource use shifted in bivariate isotopic space seasonally but not across years when combining all species and habitats. Inferred spring diet (based on fur samples) was highly diverse and overlapping. Summer isotopic values (based on liver tissue) in woody habitat treatments were narrower and overlapped less than within grassland habitats. Consumers generally shifted from C4 herbivory to C3 herbivory, or greater omnivory, when analyzing grassland, shrubland, and woodland habitats respectively. Within the tallgrass prairie ecosystem, small mammal populations in herbaceous-dominated habitats use a broader variety of resources than small mammals in proximate woody-dominated habitats. As native grasslands experience woody encroachment, small mammal assemblages experience turnover of dominant species and associated changes in diet. Ecosystem changes such as cessation of frequent fire resulting in more woody habitats may include reduced roles by native small mammals as consumers/dispersers/propagators of native grassland plants.

}, keywords = {LTER-KNZ}, doi = {10.1002/ecs2.3441}, url = {https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecs2.3441}, author = {Hope, A.G. and Gragg, S.F. and Nippert, J.B. and Combe, F.J.} } @article {6071, title = {Cultural conformity and persistence in Dickcissel song are higher in locations in which males show high site fidelity}, journal = {Ornithology}, volume = {139}, year = {2021}, pages = {1-17}, keywords = {LTER-KNZ}, doi = {10.1093/ornithology/ukab061}, url = {https://academic.oup.com/auk/article/doi/10.1093/ornithology/ukab061/6380842}, author = {Parker, Timothy H and Sousa, Bridget and Leu, Stephan T and Edmondson, Stacy and Foo, Cecily and Strauss, Amy and Kahl, Hanna and Ballinger, Kristen and Ross, Eric and {\ss}e Ruse, Mareile and Sandsten, Maria and Verheijen, Bram H F and Jensen, William} } @article {KNZ002032, title = {Communities 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 = {31 - 49}, keywords = {LTER-KNZ}, url = {https://bioone.org/journals/Transactions-of-the-Kansas-Academy-of-Science/volume-123/issue-1-2/062.123.0103/Communities-of-Small-Mammals-Tallgrass-Prairie-and-Prescribed-Fire/10.1660/062.123.0103.short}, author = {D.W. Kaufman and Kaufman, G.A. and Kaufman, D.M. and Reed, A.W. and Rehmeier, R.L.} } @article {KNZ002051, title = {Connections and feedback: Aquatic, plant, and soil microbiomes in heterogeneous and changing environments}, journal = {BioScience}, volume = {70}, year = {2020}, pages = {548 - 562}, abstract = {

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

}, keywords = {LTER-KNZ}, doi = {10.1093/biosci/biaa046}, url = {https://academic.oup.com/bioscience/article/70/7/548/5826958}, author = {W. K. Dodds and L.H. Zeglin and Ramos, R.J. and Platt, T.G. and Pandey, A. and Michaels, T. and Masigol, M. and Klompen, A.M.L. and Kelly, M.C. and A. Jumpponen and Hauser, E. and Hansen, P.M. and Greer, M.J. and Fattahi, N. and Delavaux, C.S. and Connell, R.K. and Billings, S. and Bever, J.D. and Barua, N. and Agusto, F.B.} } @article {KNZ001889, title = {Causes and consequences of avian within-season dispersal decisions in a dynamic grassland environment}, journal = {Animal Behaviour}, volume = {155}, year = {2019}, pages = {77 - 87}, abstract = {

Understanding the causes and consequences of dispersal is key to identifying selective pressures underlying species-level variation in biogeography, metapopulation dynamics and adaptive capacity. We tested the hypotheses that nest predation and/or brood parasitism avoidance drive breeding dispersal decisions and that dispersal functions to reduce subsequent reproductive failure in grasshopper sparrows, Ammodramus savannarum, breeding in eastern Kansas, U.S.A. Over 2 years, we monitored the fate of 222 nests and the movements of 144 parents. We established the spatiotemporal patterns of nest success among all nests, then related nest predation and parasitism to subsequent dispersal behaviour and reproductive success. Birds were more likely to disperse following nest predation, but decisions were unaffected by parasitism. Dispersers experienced higher chances of subsequent nest survival than did site-faithful individuals. Although second nests were parasitized less often than were first nests, dispersers did not experience substantially lower parasitism than did site-faithful individuals, suggesting that the challenges of predation and brood parasitism may be solved in different ways. This study represents one of few tests of alternative hypotheses explaining dispersal decisions of songbirds within seasons and represents a rare case study of the consequences of breeding dispersal on subsequent reproductive success. Our results suggest that differences in dispersal tendencies may result from variation in risk-response thresholds rather than alternative causal drivers.

}, keywords = {LTER-KNZ, breeding dispersal, habitat variability, nomadism, settlement, territory switching, within-season dispersal}, doi = {10.1016/j.anbehav.2019.06.009}, url = {https://doi.org/10.1016/j.anbehav.2019.06.009}, author = {Williams, E.J. and W. A. Boyle} } @article {KNZ001949, title = {Changes in potential nitrous oxide efflux during grassland restoration}, journal = {Journal of Environmental Quality}, volume = {48}, year = {2019}, pages = {1913-1917}, abstract = {

14 Nitrous oxide efflux from soil is an important ecological process in terms of global climate 15 impacts, stratospheric chemistry, and soil fertility. The effects of grassland restoration on nitrous 16 oxide (N 2 O) efflux in formerly cultivated agricultural soils are not well known. Restoration 17 changes the storage and availability of soil C and N, with potential consequences for N 2 O efflux. 18 We examined changes in potential N 2 O efflux across a 35-year chronosequence of grassland 19 restorations, using lab incubations at moisture levels that maximized N 2 O emissions, to quantify 20 the relationship between N 2 O efflux and soil properties known to change predictably during 21 grassland restoration. We found that restoring cultivated agricultural land to grassland rapidly 22 decreased N 2 O efflux from soils, though native prairie had a potential N 2 O efflux higher than the 23 agricultural land. The oldest restoration had N 2 O efflux 50 times lower than native prairie. 24 Changes in N 2 O efflux were more strongly correlated with N mineralization than C.

}, keywords = {LTER-KNZ}, author = {Scott, D.A. and Rosenzweig, S.T. and S.G. Baer and John M. Blair} } @article {KNZ001950, title = {Characterizing grassland fire activity in the Flint Hills region and air quality using satellite and routine surface monitor data}, journal = {Science of The Total Environment}, volume = {659}, year = {2019}, pages = {1555 - 1566}, abstract = {

Prescribed grassland fires in the Flint Hills region of central Kansas and northern Oklahoma are a common tool for land management. Local to regional scale impacts on air quality from grassland fires in this region are not well understood, which is important as these types of prescribed fires may increase in the future to preserve broader areas of native grasses in the central U.S. Routine air quality and deposition measurements from sites in and near the Flint Hills were examined for coincident increases during periods of increased prescribed grassland fires. Prescribed fire activity in this region was quantified using satellite detections and multiple publicly available data products of area burned information. March and April comprise over half (41 to 93\%) of all annual fire detections in the Flint Hills region seen from satellites between 2007 and 2018 excluding drought years. Annual total fire detections in this region range between 1 and 12 thousand and account for approximately 3\% of all fire detections in the contiguous U.S. Annual acres burned ranged from 0.2 to 2 million acres based on U.S. EPA\&$\#$39;s National Emission Inventory, which accounts for 4 to 38\% of grasslands in the area. A comparison of weekly standardized anomalies suggests a relationship between periods of increased grassland fire activity and elevated levels of PM2.5 organic carbon, elemental carbon, and potassium. Daily 1-hr maximum ozone (O3), ammonia (NH3), sulfur dioxide (SO2), and oxidized nitrogen gases measured at Konza Prairie also had increased levels when prescribed grassland fire activity was highest. This detailed characterization of prescribed fire activity in the Flint Hills and associated air quality impacts will benefit future efforts to understand changes in atmospheric composition due to changing land management practices.

}, keywords = {LTER-KNZ}, issn = {00489697}, doi = {10.1016/j.scitotenv.2018.12.427}, url = {https://www.sciencedirect.com/science/article/pii/S0048969718353221?via\%3Dihub}, author = {Baker, K.R. and Koplitz, S.N. and Foley, K.M. and Avey, L. and Hawkins, A.} } @article {KNZ001951, title = {Climate affects plant-soil feedback of native and invasive grasses: negative feedbacks in stable but not in variable environments}, journal = {Frontiers in Ecology and Evolution}, volume = {7}, year = {2019}, abstract = {

The plant-soil feedback framework allows researchers to target the interaction of plants and root-associated microbes and to determine its interplay on plant-plant interactions. Plant-soil feedbacks in terrestrial ecology are well-documented, but the strength and direction of feedbacks as influenced by abiotic environmental factors, such as temperature and soil moisture, has not been fully explored. In our study, we examined plant-soil feedback responses of both cool- and warm-season native and non-native grasses to elevated temperatures (ambient and +5\°C) and soil moisture (100 and 75\% field capacity). In a previous experiment, grasses were grown under temperature and soil moisture conditions similar to our current study. The resultant trained soil communities served as the inoculum sources for our current experiment. We found that consistent training and experimental temperatures resulted in negative PSF, where plants produced greater biomass in soils conditioned by heterospecifics. However, the direction of PSF was reversed when training and experimental conditions were mismatched. That is, when training and experimental temperatures mirrored one another, negative PSF occurred, suggesting coexistence between the two species is likely under these conditions. However, when only training or testing temperatures were elevated, positive PSF were detected, favoring the non-native species. These alterations in plant-soil feedbacks were relatively consistent across pairings of warm- and cool-season grasses. Overall, our results indicate inconsistent year-to-year environmental conditions, such as extreme temperatures, may undermine the stabilizing forces of negative PSF and favor of non-native grasses.

}, keywords = {LTER-KNZ}, doi = {10.3389/fevo.2019.00419}, url = {https://www.frontiersin.org/articles/10.3389/fevo.2019.00419/full$\#$h6}, author = {E.B. Duell and Zaiger, Katherine and Bever, James D. and G.T. Wilson} } @article {KNZ001943, title = {The combined effects of an extreme heatwave and wildfire on tallgrass prairie vegetation}, journal = {Journal of Vegetation Science}, volume = {30}, year = {2019}, pages = {687 - 697}, abstract = {

Questions: Climate extremes are predicted to become more common in many ecosystems. Climate extremes can promote and interact with disturbances, but the combined effects of climate extremes and disturbances have not been quantified in many ecosystems. In this study, we ask whether the dual impact of a climate extreme and concomitant disturbance (wildfire) has a greater affect than a climate extreme alone.
Location: Tallgrass prairie in the Konza Prairie Biological Station, northeastern Kansas, USA.
Methods: We quantified the response of a tallgrass prairie plant community to a 2-year climate extreme of low growing-season precipitation and high temperatures. In the first year of the climate extreme, a subset of plots was burned by a growing-season wildfire. This natural experiment allowed us to compare community responses to a climate extreme with and without wildfire.
Results: In plots exposed to the climate extreme but not wildfire, community structure, diversity, and composition showed minor to insignificant changes, such as a 20\% reduction in grass cover and a slight increase in species diversity. Plots exposed to both the climate extreme and wildfire underwent larger changes, including an 80\% reduction in grass cover, 50\% increase in forb cover, and increased plant diversity. Two years after the climate extreme, structural shifts in burned plots showed little sign of recovery, indicating a potentially lasting shift in plant community structure.
Conclusions: Our results suggest that community responses to climate extremes need to account for climate-related disturbances \— in this case, high temperatures, drought and wildfire. This response diverged from our expectation that heat, drought, and an additional fire would favor grasses. Although growing-season wildfires in tallgrass prairie have been rare in recent decades, they will likely become more common with climate change, potentially leading to changes in grassland structure.

}, keywords = {LTER-KNZ}, doi = {10.1111/jvs.12750}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/jvs.12750}, author = {Z. Ratajczak and Churchill, Amber C. and Ladwig, Laura M. and Taylor, Jeff H. and Scott. L. Collins} } @article {KNZ001952, title = {Community Physiological Ecology}, journal = {Trends in Ecology \& Evolution}, volume = {34}, year = {2019}, pages = {510 - 518}, keywords = {LTER-KNZ}, doi = {10.1016/j.tree.2019.02.002}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0169534719300497}, author = {Warne, R.W. and S.G. Baer and Boyles, J.G.} } @article {KNZ001953, title = {A comprehensive approach to analyzing community dynamics using rank abundance curves}, journal = {Ecosphere}, volume = {10}, year = {2019}, pages = {e02881}, abstract = {

Univariate and multivariate methods are commonly used to explore the spatial and temporaldynamics of ecological communities, but each has limitations, including oversimplification or abstractionof communities. Rank abundance curves (RACs) potentially integrate these existing methodologies bydetailing species-level community changes. Here, we had three goals:first, to simplify analysis of commu-nity dynamics by developing a coordinated set of R functions, and second, to demystify the relationshipsamong univariate, multivariate, and RACs measures, and examine how each is influenced by the commu-nity parameters as well as data collection methods. We developed new functions for studying temporalchanges and spatial differences in RACs in an update to the R package library(\“codyn\”), alongside othernew functions to calculate univariate and multivariate measures of community dynamics. We also devel-oped a new approach to studying changes in the shape of RAC curves. The R package update presentedhere increases the accessibility of univariate and multivariate measures of community change over timeand difference over space. Next, we use simulated and real data to assess the RAC and multivariate mea-sures that are output from our new functions, studying (1) if they are influenced by species richness andevenness, temporal turnover, and spatial variability and (2) how the measures are related to each other.Lastly, we explore the use of the measures with an example from a long-term nutrient addition experiment.Wefind that the RAC and multivariate measures are not sensitive to species richness and evenness andthat all the measures detail unique aspects of temporal change or spatial differences. We alsofind that spe-cies reordering is the strongest correlate of a multivariate measure of compositional change and explainsmost community change observed in long-term nutrient addition experiment. Overall, we show that spe-cies reordering is potentially an understudied determinant of community changes over time or differencesbetween treatments. The functions developed here should enhance the use of RACs to further explore thedynamics of ecological communities.

}, keywords = {LTER-KNZ}, doi = {10.1002/ecs2.2881}, url = {https://esajournals.onlinelibrary.wiley.com/doi/epdf/10.1002/ecs2.2881}, author = {M.L. Avolio and Carroll, I. and Scott. L. Collins and Houseman, Gregory R. and Hallett, L.M. and Isbell, F.L. and Koerner, S.E. and Kimberly J. Komatsu and M.D. Smith and K.R. Wilcox} } @article {KNZ001928, title = {Carbon exchange responses of a mesic grassland to an extreme gradient of precipitation}, journal = {Oecologia}, year = {2018}, pages = {1 -12}, abstract = {

Growing evidence indicates that ecosystem processes may be differentially sensitive to dry versus wet years, and that current understanding of how precipitation affects ecosystem processes may not be predictive of responses to extremes. In an experiment within a mesic grassland, we addressed this uncertainty by assessing responses of two key carbon exchange processes\—aboveground net primary production (ANPP) and soil respiration (Rs) - to an extensive gradient of growing season precipitation. This gradient comprised 11 levels that specifically included extreme values in precipitation; defined as the 1st, 5th, 95th, and 99th percentiles of the 112-year climate record. Across treatments, our experimental precipitation gradient linearly increased soil moisture availability in the rooting zone (upper 20\ cm). Relative to ANPP under nominal precipitation amounts (defined as between the 15th and 85th percentiles), the magnitude of ANPP responses were greatest to extreme increases in precipitation, with an underlying linear response to both precipitation and soil moisture gradients. By contrast, Rs exhibited marginally greater responses to dry versus wet extremes, with a saturating relationship best explaining responses of Rs to both precipitation and soil moisture. Our findings indicate a linear relationship between ANPP and precipitation after incorporating responses to precipitation extremes in the ANPP\–precipitation relationship, yet in contrast saturating responses of Rs. As a result, current linear ANPP\–precipitation relationships (up to ~\ 1000\ mm) within mesic grasslands appear to hold as appropriate benchmarks for ecosystems models, yet such models should incorporate nonlinearities in responses of Rs amid increased frequencies and magnitudes of precipitation extremes.

}, keywords = {LTER-KNZ, Climate extremes, Drought, Primary production, Rainfall, soil respiration}, doi = {10.1007/s00442-018-4284-2}, url = {https://link.springer.com/article/10.1007/s00442-018-4284-2}, author = {Felton, A.J. and Alan K. Knapp and M.D. Smith} } @article {KNZ001888, title = {Change in dominance determines herbivore effects on plant biodiversity}, journal = {Nature Ecology and Evolution}, volume = {2}, year = {2018}, pages = {1925-1932}, abstract = {

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

}, keywords = {LTER-KNZ}, doi = {https://doi.org/10.1038/s41559-018-0696-y}, url = {https://www.nature.com/articles/s41559-018-0696-y$\#$article-info}, author = {Koerner, S.E. and M.D. Smith and Burkepile, D.E. and N.P. Hanan and M.L. Avolio and Scott. L. Collins and Alan K. Knapp and N.P. Lemoine and E.J. Forrestel and S. Eby and D.I. Thompson and G. Aguado-Santacruz and J.P. Anderson and Anderson, M. and A. Angassa and S. Bagchi and E.S. Bakker and Bastin, Gary and L.E. Baur and K.H. Beard and E.A. Beever and P.J. Bohlen and Elizabeth H. Boughton and Canestro, Don and Cesa, Ariela and Chaneton, Enrique and Cheng, Jimin and C.M. D{\textquoteright}Antonio and C. Deleglise and Fadiala. Demb{\'e}l{\'e} and Josh. Dorrough and David. J. Eldridge and Barbara. Fernandez-Going and Silvia. Fern{\'a}ndez-Lugo and Lauchlan. H. Fraser and Bill. Freedman and Gonzalo. Garc{\'\i}a-Salgado and Jacob. R. Goheen and Liang. Guo and Sean. Husheer and Moussa. Karemb{\'e} and Johannes. M. H. Knops and Tineke. Kraaij and Andrew. Kulmatiski and Minna-Maarit. Kyt{\"o}viita and Felipe. Lezama and Gregory. Loucougaray and Alejandro. Loydi, Dan G. Milchunas, and Dan.G. Milchunas, and Suzanne. J. Milton and J.W. Morgan and Claire. Moxham and Kyle. C. Nehring and Han. Olff and Todd. M. Palmer and Salvador. Rebollo and Corinna. Riginos and Anita. C. Risch and Marta Rueda and Mahesh. Sankaran and Takehiro. Sasaki and Kathryn. A. Schoenecker and Nick. L. Schultz and Martin. Sch{\"u}tz and Angelika. Schwabe and Frances. Siebert and Christian. Smit and Karen. A. Stahlheber and Christian. Storm and Dustin. J. Strong and Jishuai. Su and Yadugiri. V. Tiruvaimozhi and Claudia. Tyler and James. Val and Martijn. L. Vandegehuchte and Kari. E. Veblen and Lance. T. Vermeire and David. Ward and Jianshuang. Wu and Truman. P. Young and Qiang. Yu and Tamara. Jane. Zelikova} } @inbook {KNZ001908, title = {Chapter 5: Agriculture}, booktitle = {Second State of the Carbon Cycle Report (SOCCR2): A Sustained Assessment Report}, year = {2018}, pages = {229 - 263}, publisher = {U.S. Global Change Research Program}, organization = {U.S. Global Change Research Program}, keywords = {LTER-KNZ}, doi = {10.7930/SOCCR2.2018.Ch5}, url = {https://carbon2018.globalchange.gov/chapter/5/}, author = {Hristov, A. N. and Johnson, J. M. F. and C. W. Rice and Brown, M. E. and Conant, R. T. and Del Grosso, S. J. and Gurwick, N. P. and Rotz, C. A. and Sainju, U. M. and Skinner, R. H. and West, T. O. and Runkle, B. R. K. and Janzen, H. and Reed, S. and Cavallaro, N. and Shrestha, G. and Birdsey, R.}, editor = {Cavallaro, N. and Shrestha, G. and Mayes, M. A. and Najjar, R. and Reed, S. and Romero-Lankao, P. and Zhu, Z.} } @mastersthesis {KNZ001925, title = {Characterizing groundwater flow through merokarst, northeast Kansas}, volume = {MS Thesis}, year = {2018}, school = {University of Kansas}, type = {M.S. Thesis}, address = {Lawrence, Kansas}, keywords = {LTER-KNZ}, url = {https://kuscholarworks.ku.edu/bitstream/handle/1808/28017/Barry_ku_0099M_16194_DATA_1.pdf?sequence=1}, author = {Barry, E.} } @article {KNZ001865, title = {Codominant grasses differ in gene expression under experimental climate extremes in native tallgrass prairie}, journal = {PeerJ}, year = {2018}, pages = {e4394}, abstract = {

Extremes in climate, such as heat waves and drought, are expected to become more frequent and intense with forecasted climate change. Plant species will almost certainly differ in their responses to these stressors. We experimentally imposed a heat wave and drought in the tallgrass prairie ecosystem near Manhattan, Kansas, USA to assess transcriptional responses of two ecologically important C4 grass species, Andropogon gerardii and Sorghastrum nutans. Based on previous research, we expected that S. nutans would regulate more genes, particularly those related to stress response, under high heat and drought. Across all treatments, S. nutans showed greater expression of negative regulatory and catabolism genes while A. gerardii upregulated cellular and protein metabolism. As predicted, S. nutans showed greater sensitivity to water stress, particularly with downregulation of non-coding RNAs and upregulation of water stress and catabolism genes. A. gerardii was less sensitive to drought, although A. gerardii tended to respond with upregulation in response to drought versus S. nutans which downregulated more genes under drier conditions. Surprisingly, A. gerardii only showed minimal gene expression response to increased temperature, while S. nutans showed no response. Gene functional annotation suggested that these two species may respond to stress via different mechanisms. Specifically, A. gerardii tends to maintain molecular function while S. nutans prioritizes avoidance. Sorghastrum nutans may strategize abscisic acid response and catabolism to respond rapidly to stress. These results have important implications for success of these two important grass species under a more variable and extreme climate forecast for the future.

}, keywords = {LTER-KNZ}, doi = {https://doi.org/10.7717/peerj.4394}, url = {https://peerj.com/articles/4394/}, author = {Hoffman, Ava M. and M.L. Avolio and Alan K. Knapp and M.D. Smith} } @article {KNZ001918, title = {Continental-scale decrease in net primary productivity in streams due to climate warming}, journal = {Nature Geoscience}, volume = {11}, year = {2018}, pages = {415 - 420}, abstract = {

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

}, keywords = {LTER-KNZ}, doi = {10.1038/s41561-018-0125-5}, url = {http://www.nature.com/articles/s41561-018-0125-5}, author = {Song, Chao and W. K. Dodds and R{\"u}egg, Janine and Argerich, Alba and Baker, Christina L. and W.B. Bowden and Douglas, Michael M. and Farrell, Kaitlin J. and Flinn, Michael B. and Garcia, Erica A. and Helton, Ashley M. and Harms, Tamara K. and Jia, Shufang and Jones, Jeremy B. and Koenig, Lauren E. and Kominoski, John S. and McDowell, William H. and McMaster, Damien and Parker, Samuel P. and Rosemond, Amy D. and Ruffing, Claire M. and Sheehan, Ken R. and Trentman, Matt T. and M.R. Whiles and Wollheim, Wilfred M. and Ballantyne, Ford} } @article {KNZ001794, title = {Changes in spatial variance during a grassland to shrubland state transition}, journal = {Journal Ecology}, volume = {105}, year = {2017}, pages = {750-760}, abstract = {
  1. State transitions are changes in ecosystem structure and self-reinforcing feedbacks that are initiated when an exogenous driver variable crosses a threshold. Reversing state transitions is difficult and costly. While some state transitions are relatively rapid, many take years to decades. Outside of theoretical models, very little is known about slower state transitions and how they unfold in time and space.
  2. We quantified changes in spatial variance as a mesic grassland ecosystem shifts to a shrub-dominated state, using long-term experiments and simulations that maintain grasslands with annual fires or initiate a state transition to shrub dominance by decreasing fire frequency.
  3. In the experiments, the susceptibility to state transitions varied substantially in space. In the less frequent fire treatment, some plots became shrub-dominated around year 20 and grass extirpations began in year 25, but a third of the plots were still grass-dominated in year 37. Variable rates of state transition resulted in increasing spatial variance of grass cover over time, whereas shrub cover variance decreased. In the annually burned treatment, grasses remained dominant and the spatial variance of grass cover declined.
  4. In a separate experiment, less frequent fires were maintained for 23\ years and then switched to annual fires. The switch to annual fires occurred shortly after grass variance started to increase and a majority of these plots quickly returned to a grass dominated state.
  5. In simulations, spatial variance remained low and average grass cover was high under frequent fires. If fire frequency decreased below a threshold, the ecosystem transitioned to shrubland, with a transient increase in the spatial variance of grass cover during the transition between states.
  6. Synthesis. Spatial variability in the rate and susceptibility to state transitions is indicative of a system with a patchy spatial structure, high spatial heterogeneity and low connectivity between patches. Increases in spatial variance can serve as an indication that some patches have begun a state transition and that management interventions are needed to avoid widespread transitions. This is one of the first empirical examples where altering management after an increase in spatial variance prevented state transitions.

}, keywords = {LTER-KNZ}, doi = {10.1111/1365-2745.12696}, url = {https://besjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1365-2745.12696}, author = {Z. Ratajczak and D{\textquoteright}Odorico, P.D. and Jesse B. Nippert and Scott. L. Collins and N. Brunsell and Ravi, S.} } @mastersthesis {KNZ001837, title = {Climate change impacts on population dynamics in tallgrass~prairie: implications for species codominance}, volume = {MS Thesis}, year = {2017}, school = {Colorado State University}, type = {M.S. Thesis}, address = {Fort Collins, CO}, keywords = {LTER-KNZ}, url = {https://mountainscholar.org/handle/10217/181431}, author = {Gray, J.E.} } @article {KNZ001806, title = {Complex variation in habitat selection strategies among individuals driven by extrinsic factors}, journal = {Ecology and Evolution}, volume = {7}, year = {2017}, pages = {1802-1822}, abstract = {

Understanding behavioral strategies employed by animals to maximize fitness in the face of environmental heterogeneity, variability, and uncertainty is a central aim of animal ecology. Flexibility in behavior may be key to how animals respond to climate and environmental change. Using a mechanistic modeling framework for simultaneously quantifying the effects of habitat preference and intrinsic movement on space use at the landscape scale, we investigate how movement and habitat selection vary among individuals and years in response to forage quality\–quantity tradeoffs, environmental conditions, and variable annual climate. We evaluated the association of dynamic, biotic forage resources and static, abiotic landscape features with large grazer movement decisions in an experimental landscape, where forage resources vary in response to prescribed burning, grazing by a native herbivore, the plains bison (Bison bison bison), and a continental climate. Our goal was to determine how biotic and abiotic factors mediate bison movement decisions in a nutritionally heterogeneous grassland. We integrated spatially explicit relocations of GPS-collared bison and extensive vegetation surveys to relate movement paths to grassland attributes over a time period spanning a regionwide drought and average weather conditions. Movement decisions were affected by foliar crude content and low stature forage biomass across years with substantial interannual variation in the magnitude of selection for forage quality and quantity. These differences were associated with interannual differences in climate and growing conditions from the previous year. Our results provide experimental evidence for understanding how the forage quality\–quantity tradeoff and fine-scale topography drives fine-scale movement decisions under varying environmental conditions.

}, keywords = {LTER-KNZ}, doi = {10.1002/ece3.2764}, url = {https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.2764}, author = {Raynor, Edward J. and Beyer, Hawthorne L. and J. M. Briggs and Anthony Joern} } @article {KNZ001752, title = {Changes in soil properties, microbial biomass, and fluxes of C and N in soil following post-agricultural grassland restoration}, journal = {Applied Soil Ecology}, volume = {100}, year = {2016}, pages = {186 - 194}, abstract = {

Understanding the dynamics of soil C and N pools and fluxes following grassland restoration in formerly cultivated soils is needed to assess the capacity of this land-use change to return soil properties and function to pre-disturbance conditions. We examined changes in physical (bulk density) and chemical (pH, available P and N, and total stocks of C and N) properties, microbial biomass C and N, and transformation rates of C and N in soil (0\–10 cm depth) across a 35-year chronosequence of prairie restorations and never-cultivated (native) prairie to evaluate the rate and extent to which sowing native perennial plants into formerly cultivated soils returns soil to steady state conditions. Bulk density, available P, and extractable inorganic N decreased exponentially across the chronosequence. Soil pH increased linearly across the chronosequence to exceed that in native prairie soil. Total C and N stocks in cultivated soil were \<50\% that of native prairie, and increased at rates of 26.2 g C m\−2 year\−1 and 1.68 g N m\−2 year\−1 across the chronosequence. In the oldest restoration, total C and N stocks were 55\% and 41\% higher than the cultivated soil, respectively. Recovery of C and N stocks to levels comparable to native prairie soil was estimated to take 350 years. Microbial biomass C and N increased 5-fold. Potential C mineralization rate was comparable to native prairie soil following two decades of restoration, and exceeded native prairie in the 35-years restoration. In situ soil CO2 efflux reached equilibrium in \<30 years. Potential net N mineralization rate, however, did not exhibit a directional change across the restoration chronosequence, but was lowest in the oldest restored grasslands. Thus, cessation of tillage and sowing native vegetation leads to rapid decreases in available N and P, and promotes rapid (decadal scale) recovery of labile soil organic matter pools, but recovery of total C and N pools requires several centuries. This study suggests that soil properties related to nutrient retention and regulation of nutrient availability can be reestablished within the first few decades of restoration, while C sequestration will continue on a longer time scale.

}, keywords = {LTER-KNZ, Bulk density, chronosequence, soil respiration, SOM recovery, tallgrass prairie}, issn = {09291393}, doi = {10.1016/j.apsoil.2016.01.001}, url = {https://www.sciencedirect.com/science/article/pii/S0929139316300014?via\%3Dihub}, author = {Rosenzweig, S.T. and Carson, M.A. and S.G. Baer and John M. Blair} } @article {KNZ002022, title = {Changes in spatial and temporal trends in wet, dry, warm and cold spell length or duration indices in Kansas, USA}, journal = {International Journal of Climatology}, volume = {36}, year = {2016}, pages = {4085 - 4101}, keywords = {LTER-KNZ}, doi = {10.1002/joc.4619}, url = {http://doi.wiley.com/10.1002/joc.4619}, author = {Anandhi, Aavudai and Hutchinson, Stacy and Harrington, John and Rahmani, Vahid and Kirkham, Mary B. and C. W. Rice} } @article {KNZ001774, title = {Characterizing organic matter inputs to sediments of small, intermittent, prairie streams: a molecular marker and stable isotope approach}, journal = {Aquatic Sciences}, volume = {78}, year = {2016}, pages = {343 - 354}, abstract = {

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

}, keywords = {LTER-KNZ, 13C stable isotopes, Biomarkers, Konza Prairie, Riparian, Small streams, Watershed}, issn = {1015-1621}, doi = {10.1007/s00027-015-0435-2}, url = {https://link.springer.com/article/10.1007\%2Fs00027-015-0435-2}, author = {Pisani, O. and W. K. Dodds and Jaff{\'e}, R.} } @mastersthesis {KNZ002026, title = {Characterizing woody encroachment in the konza prairie using object-based analysis of aerial photographs}, volume = {MS Thesis}, year = {2016}, school = {University of Kansas}, type = {M.S. Thesis}, address = {Lawrence, Kansas}, abstract = {

Woody encroachment is a threat to the ecological integrity of tallgrass prairie in Kansas.\  Encroachment data that covers a large spatial and temporal scale would be valuable to managers of tallgrass prairie, but no such dataset exists.\  The objective of this research is to develop a replicable technique for creating woody vegetation maps from aerial photographs.\  Rather than using a traditional pixel-by-pixel approach to classification, this project uses an object-based approach, wherein individual pixels are grouped into meaningful image objects according to user-defined parameters and then classified.\  I created woody vegetation maps of eight watersheds in the Konza Prairie using imagery from 1978, 1991, 2003, 2006, and 2010.\  I also determined the efficacy of LIDAR data in classifying the image from 2006.\  Ground-based vegetation survey data exist for two of the watersheds included in the remote sensing portion of this study.\  I analyzed the data from the available years nearest to the imagery dates (1983, 1992, 2003, and 2007) in order to provide a measure of validation for the woody vegetation maps.\  The results of this research were used to determine the applicability of this mapping technique and to draw preliminary conclusions about the landscape-level factors associated with woody encroachment.

}, keywords = {LTER-KNZ, Flint Hills, Geographic information science and geodesy, Geography, Object-based image analysis, tallgrass prairie, woody encroachment}, url = {https://kuscholarworks.ku.edu/handle/1808/24182}, author = {Shanko, A.R.} } @article {KNZ001747, title = {Climate modifies response of non-native and native species richness to nutrient enrichment}, journal = {Philosophical Transactions of the Royal Society B: Biological Sciences}, volume = {3719371}, year = {2016}, pages = {20150273}, abstract = {

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

}, keywords = {LTER-KNZ}, issn = {0962-8436}, doi = {10.1098/rstb.2015.0273}, url = {https://royalsocietypublishing.org/doi/10.1098/rstb.2015.0273}, author = {Flores-Moreno, H. and P.B. Reich and Lind, E.M. and L.L. Sullivan and Seabloom, E.W. and Yahdjian, L. and MacDougall, A.S. and Reichmann, L.G. and J. Alberti and B{\'a}ez, S. and J.D. Bakker and Cadotte, M.W. and Caldeira, M.C. and Chaneton, E.J. and D{\textquoteright}Antonio, C.M. and Fay, P.A. and Firn, J. and Hagenah, N. and Harpole, W. S. and Iribarne, O. and Kirkman, K.P. and Knops, J.M. H. and Kimberly J. La Pierre and Laungani, R. and Leakey, A.D. B. and McCulley, R.L. and Joslin L. Moore and Pascual, J. and E.T. Borer} } @article {KNZ001745, title = {codyn: An R package of community dynamics metrics}, journal = {Methods in Ecology and Evolution}, volume = {7}, year = {2016}, pages = {1146{\textendash}1151}, abstract = {
  1. New analytical tools applied to long-term data demonstrate that ecological communities are highly dynamic over time. We developed an r package, library(\“codyn\”), to help ecologists easily implement these metrics and gain broader insights into ecological community dynamics.
  2. library(\“codyn\”) provides temporal diversity indices and community stability metrics. All functions are designed to be easily implemented over multiple replicates.
  3. Temporal diversity indices include species turnover, mean rank shifts and rate of community change over time. Community stability metrics calculate overall stability and patterns of species covariance and synchrony over time, and include a null-modelling method to test significance.
  4. Finally, library(\“codyn\”) contains vignettes that describe methods and reproduce figures from published papers to help users contextualize and apply functions to their own data.
}, keywords = {LTER-KNZ}, doi = {10.1111/2041-210X.12569}, url = {https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/2041-210X.12569}, author = {Hallett, L.M. and Jones, S.K. and MacDonald, A.A.M. and Jones, M.B. and Flynn, D.F.B. and Ripplinger, J. and Slaughter, P. and Gries, C. and Scott. L. Collins} } @article {KNZ001720, title = {Comparative ecohydrology between Cornus drummondii and Solidago canadensis in upland tallgrass prairie}, journal = {Plant Ecology}, volume = {217}, year = {2016}, pages = {267-276}, abstract = {

Woody species expansion threatens to transform mesic North American grasslands. In many tallgrass prairies of the central Great Plains with deep soil, Cornus drummondii develops large shrub islands that exhibit non-linear increases in cover through time. Reliance on soil moisture from deeper soil depths facilitates constant gas exchange rates and minimizes competition with coexisting herbaceous species. Conversely, C. drummondii growth and expansion in thin-soil locations is stochastic and these locations are typically free of large shrub islands. At the Konza Prairie in northeast Kansas, USA, we compared the ecohydrology of C. drummondii individuals to a similar-sized forb (Solidago canadensis) in thin-soil locations with varying fire frequency (4-, 20-year) and grazer abundance (bison present or absent). Gas exchange rates were relatively constant for C. drummondii, while S. canadensis declined across the growing season. For S. canadensis, maximum photosynthesis (Amax), daytime transpiration (E), and stomatal conductance (gs) were higher on ungrazed than grazed treatments. Nighttime E rates were higher in C. drummondii, accounting for over 10 \% of the daytime E rates. The water source used did not vary among contrasts, with the majority of water uptake occurring from 30 cm depth for both species. These results highlight a unique ecohydrology of C. drummondii (static water flux, and high rates of nighttime E) compared to a similar-sized, co-occurring forb. Whereas C. drummondii is infrequent in thin-soil locations, the climate conditions occurring during measurements were not a likely filter restricting persistence. Rather, drier conditions or interactions with other grassland disturbances are likely required to restrict C. drummondii encroachment in the thins-soil locations of tallgrass prairie.

}, keywords = {LTER-KNZ, Konza Prairie, Mesic grassland, photosynthesis, Stable water isotopes, Transpiration, woody encroachment}, doi = {10.1007/s11258-016-0567-z}, url = {https://link.springer.com/article/10.1007\%2Fs11258-016-0567-z}, author = {Muench, A. and O{\textquoteright}Keefe, K. and Jesse B. Nippert} } @article {KNZ001723, title = {Co-variation in methanotroph community composition and activity in three temperate grassland soils}, journal = {Soil Biology and Biochemistry}, volume = {95}, year = {2016}, pages = {78 - 86}, abstract = {

Methane is a potent greenhouse gas, and the uptake of methane by methanotrophic bacteria in oxic, well-drained soils is a key global sink. Field studies at the ecosystem scale have observed significant temporal and spatial variation in methane uptake rates, but there is considerable uncertainty about the roles of abiotic and biotic factors, including methanotroph community composition, in structuring these patterns. Here, we present an analysis of Michaelis\–Menten kinetics of methane uptake in soils collected from three North American temperate grassland sites of differing soil moisture regimes and their methanotroph community composition. The three sites were Konza Prairie in Kansas, Shortgrass Steppe in Colorado and Sevilleta in New Mexico with mean annual precipitation of 835, 320 and 244 mm, respectively. Michaelis\–Menten kinetics and methanotroph community were assessed via lab incubation and pmoA-based phylogeny, respectively. Across the precipitation gradient we observed distinct variation in Michaelis\–Menten kinetics and methanotroph community composition. Both KM and VMax values of the Michaelis\–Menten kinetics followed the trend of the mean annual precipitation (Konza Prairie \> Shortgrass Steppe \> Sevilleta). The observed six methanotroph clades were all within the γ-proteobacteria division, and included two novel clades found in Shortgrass Steppe and Sevilleta. The methanotroph communities were dominated by Methylococcus spp, JR2 clade, and USC gamma, in Konza Prairie, Shortgrass Steppe and Sevilleta soils, respectively. The distinct differences in the community composition among the three sites may help explain the functional variation of upland methanotrophy observed in KM. Taken together, the coincident differences in Michaelis\–Menten kinetics we observed suggest that methanotroph community composition can be important for CH4 uptake in controlled environments, potentially playing a role in the variation in methane uptake in the fields.

}, keywords = {LTER-KNZ, Grassland soils, Methanotroph community composition, Methanotroph phylogeny, Michaelis{\textendash}Menten kinetics}, issn = {00380717}, doi = {10.1016/j.soilbio.2015.12.014}, url = {https://www.sciencedirect.com/science/article/abs/pii/S0038071715004460?via\%3Dihub}, author = {Judd, Craig R. and Koyama, Akihiro and Simmons, Mark P. and Brewer, Paul and von Fischer, Joseph C.} } @article {KNZ001737, title = {Crab spiders (Thomisidae) attract insect flower-visitors without UV signaling}, journal = {Ecological Entomology}, volume = {41}, year = {2016}, pages = {611-617}, type = {Journal Articles}, abstract = {

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

}, keywords = {LTER-KNZ}, doi = {10.1111/een.12334}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/een.12334}, author = {Welti, E. and Putnam, S. and Anthony Joern} } @article {KNZ001722, title = {Challenging the maximum rooting depth paradigm in grasslands and savannas}, journal = {Functional Ecology}, volume = {29}, year = {2015}, pages = {739 - 745}, abstract = {
  1. For many grassland and savanna ecosystems, water limitation is a key regulator of individual plant, community and ecosystem processes. Maximum rooting depth is commonly used to characterize the susceptibility of plant species to drought. This rests on the assumption that deep-rooted plant species would have a greater total volume of soil water to exploit and should be less susceptible to episodic changes in water availability.
  2. Independent of maximum rooting depth, rooting strategies based on differences in biomass allocation with depth, uptake plasticity in relation to water availability and variation in water transport capability may all influence growth responses and susceptibility to drought. Many examples from grasslands and savannas reflect these rooting strategies among coexisting grass, forb and woody species.
  3. Here, we use a dynamic model of plant water uptake and growth to show how changes in root distribution, functional plasticity and root hydraulic conductivity have the potential to influence aboveground biomass and competitive outcomes, even when maximum rooting depth remains constant. We also show theoretically that shifts in root distribution to surface soils without changes in maximum depth can potentially outweigh the benefits of increased maximum rooting depth.
  4. Combining our current reliance on biogeographic descriptions of maximum rooting depth with insights about other, more subtle aspects of root structure and function are likely to improve our understanding of ecosystem responses to dynamic water limitation.
}, keywords = {LTER-KNZ}, doi = {10.1111/1365-2435.12390}, url = {https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2435.12390}, author = {Jesse B. Nippert and Holdo, R. M.}, editor = {Sayer, E.} } @article {KNZ001684, title = {Characterizing differences in precipitation regimes of extreme wet and dry years: Implications for climate change experiments}, journal = {Global Change Biology}, volume = {21}, year = {2015}, pages = {2624 -2633}, abstract = {

Climate change is intensifying the hydrologic cycle and is expected to increase the frequency of extreme wet and dry years. Beyond precipitation amount, extreme wet and dry years may differ in other ways, such as the number of precipitation events, event size, and the time between events. We assessed 1614 long-term (100 year) precipitation records from around the world to identify key attributes of precipitation regimes, besides amount, that distinguish statistically extreme wet from extreme dry years. In general, in regions where mean annual precipitation (MAP) exceeded 1000 mm, precipitation amounts in extreme wet and dry years differed from average years by ~40\% and 30\%, respectively. The magnitude of these deviations increased to \>60\% for dry years and to \>150\% for wet years in arid regions (MAP\<500 mm). Extreme wet years were primarily distinguished from average and extreme dry years by the presence of multiple extreme (large) daily precipitation events (events \>99th percentile of all events); these occurred twice as often in extreme wet years compared to average years. In contrast, these large precipitation events were rare in extreme dry years. Less important for distinguishing extreme wet from dry years were mean event size and frequency, or the number of dry days between events. However, extreme dry years were distinguished from average years by an increase in the number of dry days between events. These precipitation regime attributes consistently differed between extreme wet and dry years across 12 major terrestrial ecoregions from around the world, from deserts to the tropics. Thus, we recommend that climate change experiments and model simulations incorporate these differences in key precipitation regime attributes, as well as amount into treatments. This will allow experiments to more realistically simulate extreme precipitation years and more accurately assess the ecological consequences.

}, keywords = {LTER-KNZ, rainfall patterns}, doi = {10.1111/gcb.12888}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.12888}, author = {Alan K. Knapp and D.L. Hoover and K.R. Wilcox and M.L. Avolio and Koerner, S.E. and Kimberly J. La Pierre and Loik, M.E. and Luo, Y. and Sala, O.E. and M.D. Smith} } @article {KNZ001789, title = {Consistent responses of soil microbial communities to elevated nutrient inputs in grasslands across the globe}, journal = {Proceedings of the National Academy of Sciences}, volume = {112}, year = {2015}, pages = {10967 - 10972}, abstract = {

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

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

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

}, keywords = {LTER-KNZ}, doi = {10.1111/gcb.12673}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.12673}, author = {K.R. Wilcox and Von Fischer, J.C. and Muscha, J.M. and Petersen, M.K. and Alan K. Knapp} } @article {KNZ001568, title = {Cessation of burning dries soils long-term in a tallgrass prairie}, journal = {Ecosystems}, volume = {17}, year = {2014}, pages = {54 -65}, abstract = {

Soil moisture is a critical variable in grassland function, yet how fire regimes influence ecohydrology is poorly understood. By altering productivity, species composition, and litter accumulation, fire can indirectly increase or decrease soil water depletion on a range of time scales and depths in the soil profile. To better understand how fire influences soil moisture in grasslands, we analyzed 28 years of soil moisture data from two watersheds in a central North American grassland which differ in their long-term fire frequency. Across 28 years, cessation of prescribed burning initially led to wetter soils, likely as litter accumulated and both transpiration and evaporation were suppressed. Long-term, cessation of burning led to soils drying more, especially at depths greater than 75 cm. The long-term drying of deep soils is consistent with the increase in woody species in the infrequently burned grassland as woody species likely have a greater reliance on soil water from deeper soil layers compared to co-occurring herbaceous species. Despite the ecohydrological changes associated with the cessation of prescribed burning, watersheds with different burn regimes responded similarly to short-term variation in climate variation. In both watersheds, low precipitation and high temperatures led to drier soils with greater responses in soil moisture to climate variation later in the season than earlier. There is no current evidence that the cessation of burning in this ecosystem will qualitatively alter how evapotranspiration responds to climate variation, but the use of deeper soil water by woody plants has the potential for greater transpiration during dry times. In all, modeling the depth-specific responses of soil moisture and associated ecosystem processes to changes in burn regimes will likely require including responses of plant community composition over short and long time scales.

}, keywords = {LTER-KNZ, critical climate period, ecohydrology, Evapotranspiration, fire, Konza Prairie, soil moisture, woody species}, doi = {10.1007/s10021-013-9706-8}, url = {https://link.springer.com/article/10.1007\%2Fs10021-013-9706-8}, author = {Craine, J.M. and Jesse B. Nippert} } @article {KNZ001667, title = {Changes in plant community composition, not diversity, during a decade of nitrogen and phosphorus additions drive above-ground productivity in a tallgrass prairie}, journal = {Journal of Ecology}, volume = {102}, year = {2014}, pages = {1649 -1660}, abstract = {

Nutrient additions typically increase terrestrial ecosystem productivity, reduce plant diversity and alter plant community composition; however, the effects of P additions and interactions between N and P are understudied. We added both N (10 g m\−2) and three levels of P (2.5, 5 and 10 g m\−2) to a native, ungrazed tallgrass prairie burned biennially in northeastern Kansas, USA, to determine the independent and interactive effects of N and P on plant community composition and above-ground net primary productivity (ANPP). After a decade of nutrient additions, we found few effects of P alone on plant community composition, N alone had stronger effects, and N and P additions combined resulted in much larger effects than either alone. The changes in the plant community were driven by decreased abundance of C4 grasses, perhaps in response to altered interactions with mycorrhizal fungi, concurrent with increased abundance of non-N-fixing perennial and annual forbs. Surprisingly, this large shift in plant community composition had little effect on plant community richness, evenness and diversity. The shift in plant composition with N and P combined had large but variable effects on ANPP over time. Initially, N and N and P combined increased above-ground productivity of C4 grasses, but after 4 years, productivity returned to ambient levels as grasses declined in abundance and the community shifted to dominance by non-N-fixing and annual forbs. Once these forbs increased in abundance and became dominant, ANPP was more variable, with pulses in forb production only in years when the site was burned. Synthesis. We found that a decade of N and P additions interacted to drive changes in plant community composition, which had large effects on ecosystem productivity but minimal effects on plant community diversity. The large shift in species composition increased variability in ANPP over time as a consequence of the effects of burning. Thus, increased inputs of N and P to terrestrial ecosystems have the potential to alter stability of ecosystem function over time, particularly within the context of natural disturbance regimes.

}, keywords = {LTER-KNZ}, doi = {10.1111/1365-2745.12312}, url = {https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2745.12312}, author = {M.L. Avolio and Koerner, S.E. and Kimberly J. La Pierre and K.R. Wilcox and G.T. Wilson and M.D. Smith and Scott. L. Collins} } @article {KNZ001609, title = {Colonization and recovery of invertebrate ecosystem engineers during prairie restoration}, journal = {Restoration Ecology}, volume = {22}, year = {2014}, pages = {456 -464}, abstract = {

Ants (Hymenoptera: Formicidae) and earthworms (Oligochaeta) are considered ecosystem engineers because they form biogenic structures in the soil that influence resource supply. The objectives of this study were to quantify recovery dynamics of these invertebrate groups across a chronosequence of restored prairies and elucidate whether changes in the abundance and biomass of ants and earthworms were related to key plant and ecosystem properties. We sampled ants and earthworms from cultivated fields, grasslands restored from 1 to 21 years, and native prairie. Ant abundance and biomass peaked between 5 and 8 years of restoration and abundance was 198 times greater than cultivated fields. Earthworm abundance increased linearly across the chronosequence and became representative of native prairie, but all earthworm populations were dominated by European species. Ant abundance and biomass were positively correlated with plant diversity and plant richness, whereas earthworm abundance biomass was only related to surface litter. These results demonstrate that earthworm abundance increases with time since cessation of cultivation and concomitant with prairie establishment, whereas the abundance and biomass of ants are more related to the structure of restored plant communities than time. The dominance of exotic earthworms in these restorations, coupled with their capacity to alter soil properties and processes may represent novel conditions for grassland development.

}, keywords = {LTER-KNZ, ants, chronosequence, earthworms, Illinois, prairie, restoration, soil fauna}, doi = {10.1111/rec.12084}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/rec.12084}, author = {Wodika, B.R. and S.G. Baer and Klopf, R.P.} } @article {KNZ001638, title = {Comparing nondestructive and destructive methods of measuring leaf chlorophyll content: tracking changes in foliar chlorophyll of five Andropogon gerardii ecotypes (Poaceae)}, journal = {Photosynthetica}, volume = {52}, year = {2014}, pages = {511-518}, keywords = {LTER-KNZ}, author = {Caudle, K.L. and Johnson, L.C. and S.G. Baer and Maricle, B.R.} } @article {KNZ001690, title = {Contrasting sensitivities of two dominant C4 grasses to heat waves and drought}, journal = {Plant Ecology}, volume = {215}, year = {2014}, pages = {721 -731}, abstract = {

Heat waves and droughts are predicted to increase in frequency and intensity with climate change. However, we lack a mechanistic understanding of the independent and interactive effects of severe heat and water stress for most ecosystems. In a mesic tallgrass prairie ecosystem, we used a factorial experimental approach to assess ecophysiological and productivity responses of two dominant C4 grasses, Andropogon gerardii and Sorghastrum nutans, to a season-long drought and a mid-summer heat wave at four intensities. We hypothesized that drought would have greater impacts than heat waves, that combined effects would be greater than either factor alone, and that the dominant grasses would differ in their responses to heat and water heat stress. We detected significant reductions in photosynthesis, leaf water potential, and productivity with drought but few direct responses to the heat waves. Surprisingly, there was no additive effect of heat and water stress on any plant response. However, S. nutans was more sensitive than A. gerardii to drought. In this grassland, water stress will likely dominate photosynthetic and productivity responses caused by discrete drought and heat wave events, rather than direct or additive effects of heat stress, with differential sensitivity in these grasses altering future ecosystem structure and function.

}, keywords = {LTER-KNZ, Climate change, Climate extremes, Mesic grassland, photosynthesis, productivity}, doi = {10.1007/s11258-014-0345-8}, url = {https://link.springer.com/article/10.1007\%2Fs11258-014-0345-8}, author = {D.L. Hoover and M.D. Smith} } @article {KNZ001610, title = {Convergent and contingent community responses to grass source and dominance during prairie restoration across a longitudinal gradient}, journal = {Environmental Management}, volume = {53}, year = {2014}, pages = {252 -265}, abstract = {

Restoring prairie on formerly cultivated land begins by selecting propagule seed sources and the diversity of species to reintroduce. This study examined the effects of dominant grass propagule source (cultivar vs. non-cultivar) and sown propagule diversity (grass:forb sowing ratio) on plant community structure. Two field experiments were established in Kansas and Illinois consisting of identical split plot designs. Dominant grass source was assigned as the whole-plot factor, and sown dominance of grasses (five levels of seeded grass dominance) as the subplot factor. Species density, cover, and diversity were quantified for 5 years. The effect of dominant grass source on the cover of focal grasses, sown species, and volunteer species was contingent upon location, with variation between dominant grass sources observed exclusively in Kansas. Species density and diversity showed regionally convergent patterns in response to dominant grass source. Contrary to our hypotheses, total species density and diversity were not lower in the presence of grass cultivars, the grass source we had predicted would be more competitive. Sown grass dominance effects on the cover of the focal grass species were contingent upon location resulting from establishment corresponding better to the assigned treatments in Illinois. All other cover groups showed regionally convergent patterns, with lower cover of volunteers and higher cover of sown forbs, diversity, and species density in the lowest sown grass dominance treatment in both sites. Thus, decisions regarding the diversity of propagules to reintroduce had more consequence for plant community structure than cultivar or non-cultivar source of dominant grasses.

}, keywords = {LTER-KNZ, Ecotype, grassland, restoration, Seed source}, doi = {10.1007/s00267-013-0209-3}, url = {https://link.springer.com/article/10.1007\%2Fs00267-013-0209-3}, author = {Klopf, R.P. and S.G. Baer and D.J. Gibson} } @article {KNZ001640, title = {Convergent phylogenetic and functional responses to altered fire regimes in mesic savanna grasslands of North America and South Africa}, journal = {New Phytologist}, volume = {203}, year = {2014}, pages = {1000 -1011}, abstract = {

The importance of fire in the creation and maintenance of mesic grassland communities is well recognized. Improved understanding of how grasses \– the dominant clade in these important ecosystems \– will respond to alterations in fire regimes is needed in the face of anthropogenically driven climate and land-use change. Here, we examined how grass communities shift in response to experimentally manipulated fire regimes at multiple levels of community diversity \– taxonomic, phylogenetic and functional \– in C4-dominanted mesic savanna grassland sites with similar structure and physiognomy, yet disparate biogeographic histories. We found that the grass communities were similar in their phylogenetic response and aspects of their functional response to high fire frequency. Both sites exhibited phylogenetic clustering of highly abundant species in annually burned plots, driven by species of the Andropogoneae, and a narrow range of functional strategies associated with rapid post-fire regeneration in a high-light, nitrogen-limited environment. By examining multiple facets of diversity in a comparative context, we identified convergent phylogenetic and functional responses to altered fire regimes in two mesic savanna grasslands. Our results highlight the importance of a common filtering process associated with fire that is consistent across grasslands of disparate biogeographic histories and taxonomic representation.

}, keywords = {LTER-KNZ}, doi = {10.1111/nph.12846}, url = {https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.12846}, author = {Forrestel, E.J. and M.J. Donoghue and M.D. Smith} } @phdthesis {KNZ001561, title = {Community and ecosystem changes in tallgrass prairie restorations: the effects of population source and diversity}, volume = {PhD. Dissertation}, year = {2013}, school = {Southern Illinois University}, type = {Ph.D. Thesis}, address = {Carbondale, IL}, abstract = {

The overall objective of this study was to quantify the effects of dominant grass propagule source (i.e., cultivar vs. non-cultivar) and seeded diversity of propagules on community structure and ecosystem function during prairie restoration. Two field experiments, and two chronosequences were used to investigate this main objective. The two field experiments were established at the same latitude separated by 620 km (corresponding to a precipitation gradient from eastern Kansas to western Illinois), and consisted of a split plot design, with dominant grass source as the whole-plot factor (2 levels) and seeded dominance of grasses as the subplot factor (5 levels). Percent cover of each species in each treatment combination was quantified during the first five years of restoration. Total plant species richness and diversity were not adversely affected by cultivars in Kansas or Illinois. The effect of the dominant grass population source on the cover of focal grasses, planted species, and volunteer species were contingent upon location. By the fifth year of restoration, diversity and richness were greatest, and cover of volunteer species was lowest in the low grass dominance (i.e., high diversity) treatment. ANPP, as well as total, microbial, and mineralizable pools of C and N were measured to quantify ecosystem function in these two field experiments. Changes in ecosystem function in Kansas and Illinois were primarily driven by time and regional abiotic differences, not propagule source or seeded diversity. The effect of plant species diversity on ecosystem function was further investigated at a landscape scale by developing and sampling two chronosequences of high (HDC; n=20) and low diversity (LDC; n=15) prairies spanning over two decades of restoration in northwestern Illinois. In general most metrics of ecosystem function in both chronosequences moved towards levels measured in remnant prairies. While the constituent prairies of the HDC had higher species richness, diversity, and more rapidly increasing root biomass than the fields of the LDC, recovery of other important ecosystem functions including aboveground net primary productivity, total, microbial, and mineralizable soil C, and soil aggregate mean weighted diameter were achieved equally well with either high or low diversity prairie plantings.

}, keywords = {LTER-KNZ}, url = {http://opensiuc.lib.siu.edu/dissertations/684/}, author = {Klopf, R.P.} } @article {KNZ001531, title = {Comparing surface and mid-tropospheric CO2 concentrations from central U.S. grasslands}, journal = {entropy}, volume = {15}, year = {2013}, pages = {606 -623}, abstract = {

Comparisons of eddy covariance (EC) tower measurements of CO2 concentration with mid-tropospheric observations from the Atmospheric Infrared Sounder (AIRS) allow for evaluation of the rising global signal of this greenhouse gas in relation to surface carbon dynamics. Using an information theory approach combining relative entropy and wavelet multi-resolution analysis, this study has explored correlations and divergences between mid-tropospheric and surface CO2 concentrations in grasslands of northeastern Kansas. Results show that surface CO2 measurements at the Kansas Field Station (KFS) and the Konza Prairie Biological Stations 1B (KZU) and 4B (K4B) with different land-cover types correlate well with mid-tropospheric CO2 in this region at the 512-day timescale between 2007 and 2010. Relative entropy further reveals that AIRS observations are indicative of surface CO2 concentrations for all land-cover types on monthly (32-day) and longer timescales. AIRS observations are also similar to CO2 concentrations at shorter timescales at sites KFS and K4B experiencing woody encroachment, though these results require further investigation. Differences in species composition and microclimate add to the variability of surface concentrations compared with mid-tropospheric observations.

}, keywords = {LTER-KNZ, Atmospheric Infrared Sounder, Eddy covariance, information theory, Konza Prairie, relative entropy, wavelets}, doi = {10.3390/e15020606}, url = {https://www.mdpi.com/1099-4300/15/2/606}, author = {Cochran, F.V. and N. Brunsell and Mechem, D.B.} } @article {KNZ001538, title = {Coordinated distributed experiments: an emerging tool for testing global hypotheses in ecology and environmental science}, journal = {Frontiers in Ecology and the Environment}, volume = {11}, year = {2013}, pages = {147 -155}, abstract = {

There is a growing realization among scientists and policy makers that an increased understanding of today\&$\#$39;s environmental issues requires international collaboration and data synthesis. Meta-analyses have served this role in ecology for more than a decade, but the different experimental methodologies researchers use can limit the strength of the meta-analytic approach. Considering the global nature of many environmental issues, a new collaborative approach, which we call coordinated distributed experiments (CDEs), is needed that will control for both spatial and temporal scale, and that encompasses large geographic ranges. Ecological CDEs, involving standardized, controlled protocols, have the potential to advance our understanding of general principles in ecology and environmental science.

}, keywords = {LTER-KNZ}, doi = {10.1890/110279}, url = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/110279}, author = {Fraser, L.H. and Henry, H.A. and Carlyle, C.N. and White, S.R. and Beierkuhnlein, C. and Cahill, J.F. and Casper, B.B. and Cleland, E.E. and Scott. L. Collins and Dukes, J.S. and Alan K. Knapp and Lind, E. and Long, R. and Luo, Y. and P.B. Reich and M.D. Smith and Sternberg, M. and Turkington, R.} } @article {KNZ001546, title = {Correlations between genetic and species diversity: effects of resource quantity and heterogeneity}, journal = {Journal of Vegetation Science}, volume = {24}, year = {2013}, pages = {1185 -1194}, abstract = {

Questions It is hypothesized that species and genetic diversity are correlated because niche differentiation among species and genotypes is either affected by the same processes (positive) or each level restricts the amount of diversity in the other (negative). Although many studies have observed both positive and negative relationships, others have found no correlation between the two diversity measures. Are measures of species (richness, diversity and evenness) and genetic diversity correlated, and how does resource (soil moisture, light, nitrogen and phosphorus) quantities and heterogeneity affect both levels of diversity? Location Intact tallgrass prairie at Konza Prairie Biological Station, northeast Kansas, US. Methods We investigate the correlation between plant species and genetic diversity in a long-term precipitation manipulation experiment \– the Rainfall Manipulation Plots (RaMPs) \– located in intact tallgrass prairie as well as adjacent non-manipulated prairie. The RaMPs experiment has been imposing ambient and more variable precipitation regimes (a 50\% increase in timing between rainfall events without changing total rainfall amount) during the growing season since 1998, resulting in reduced mean soil moisture and increased soil moisture variability. Thus, the RaMPs and non-manipulated prairie plots capture a range of soil moisture amounts and variability. Genetic diversity (measured as genotype richness and genomic dissimilarity among individuals) was quantified for the dominant grass species, Andropogon gerardii, which has large impacts on plant community structure and ecosystem function. Results We found species and genetic diversity were not significantly correlated. Genotypic richness was negatively related to soil moisture variability, but measures of species diversity were not. In the non-manipulated plots only, we found generally negative relationships between resource quantity (light and nitrogen) and community diversity, and positive relationships between resource heterogeneity (CV of light) and community diversity. Conclusions Our results suggest that a lack of a positive or negative relationship between species and genetic diversity could be due to these two levels of diversity responding differently to the identity, quantity and heterogeneity of resources.

}, keywords = {LTER-KNZ, Andropogon gerardii, C4 grass, dominant species, grassland, Resource heterogeneity, Resource quantity, Species genetic diversity correlation}, doi = {10.1111/jvs.12042}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/jvs.12042}, author = {M.L. Avolio and M.D. Smith} } @article {KNZ001502, title = {Changes in stomatal conductance along grass blades reflect changes in leaf structure}, journal = {Plant Cell and Environment}, volume = {35}, year = {2012}, pages = {1040 -1049}, abstract = {

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

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1365-3040.2011.02470.x}, url = {https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-3040.2011.02470.x}, author = {Ocheltree, T.W. and Jesse B. Nippert and Prasad, P.V.V.} } @article {KNZ001535, title = {Characterizing prevalence and ecological impact of non-native terrestrial isopods (Isopoda, Oniscidea) in tallgrass prairie}, journal = {Crustaceana}, volume = {85}, year = {2012}, pages = {1499 -1511}, abstract = {

Isopods are terrestrial crustaceans whose role and impact in the tallgrass prairie ecosystem remains little explored despite being rather prevalent non-native inhabitants. To better understand this role, we conducted two related studies. The first was a rapid survey of isopods in experimental treatments at Konza Prairie LTER site to investigate the diversity and relative abundance of isopod species present. Of the four species known in Kansas thus far, all non-native, Armadillidium vulgare (Latreille, 1804) was the most abundantly found, accounting for 93\% of individuals found. Armadillidium nasatum Budde-Lund, 1885, Cylisticus convexus (De Geer, 1778) and Porcellionides pruinosus (Brandt, 1833) were also found and we report the first record of Porcellio laevis Latreille, 1804 in the State of Kansas. Survey results showed no evidence for a relationship between isopod abundance and fire frequency or grazing treatment. The second experiment was a food preference study to explore granivory in non-native isopods and characterize their seed predator behavior on native plants. Individual isopods were placed in Petri dishes with food options including leaf litter and seeds from one of 15 species; dishes were then incubated for 6-12 days and preference was assessed based on pre- and post-trial weights of the feed and individual isopod. Isopods showed a significant preference for leaves compared to seeds in nine of the 15 seed species evaluated; no evidence for leaf-vs.-seed preference was apparent in the remaining six seed species. However, in all cases, isopods did consume some amount of seeds even when leaf litter was present. Taken together, the relatively low abundance of non-native terrestrial isopods and their lack of apparent preference for native plant seeds suggest that isopods are unlikely to pose considerable threat to tallgrass prairie ecosystems. More extensive research, including a preference study with greater representation of seed species and a quantitative survey throughout the year, would be needed to further characterize the ecological role of isopods in the tallgrass prairie.

}, keywords = {LTER-KNZ}, doi = {10.1163/15685403-00003126}, url = {https://brill.com/view/journals/cr/85/12-13/article-p1499_8.xml}, author = {Singer, C.L. and Bello, N.M. and Snyder, B.A.} } @article {KNZ001440, title = {Climate change alters growing season flux dynamics in mesic grasslands}, journal = {Theoretical and Applied Climatology}, volume = {107}, year = {2012}, pages = {427 -440}, abstract = {

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

}, keywords = {LTER-KNZ, ecohydrology, Konza Prairie, Low-dimensional modeling, Nonlinear interactions, Soil moisture feedback}, doi = {10.1007/s00704-011-0484-y}, url = {https://link.springer.com/article/10.1007\%2Fs00704-011-0484-y}, author = {Petrie, M.D. and N. Brunsell and Jesse B. Nippert} } @article {KNZ001468, title = {Comment on "Global Resilience of Tropical Forest and Savanna to Critical Transitions"}, journal = {Science}, volume = {336}, year = {2012}, pages = {541 -}, abstract = {

Hirota et al. (Reports, 14 October 2011, p. 232) used spatial data to show that grasslands, savannas, and forests represent opposing stable states. Reanalyzing their data and drawing from temporal studies, we argue that spatial analyses underestimate the bistability of grasslands and savannas due to limitations of substituting space for time. We propose that temporal and spatial data are needed to predict critical transitions between grasslands and savannas.

}, keywords = {LTER-KNZ}, doi = {10.1126/science.1219346}, url = {http://science.sciencemag.org/content/336/6081/541.3}, author = {Z. Ratajczak and Jesse B. Nippert} } @article {KNZ001514, title = {Community stability does not preclude ecosystem sensitivity to chronic resource alteration}, journal = {Functional Ecology}, volume = {26}, year = {2012}, pages = {1231 -1233}, keywords = {LTER-KNZ}, doi = {10.1111/j.1365-2435.2012.02053.x}, url = {https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2435.2012.02053.x}, author = {Alan K. Knapp and J. M. Briggs and M.D. Smith} } @article {KNZ001462, title = {Community traitscape of foliar nitrogen isotopes reveals N availabiity patterns in a tallgrass prairie}, journal = {Plant and Soil}, volume = {356}, year = {2012}, pages = {395 -403}, abstract = {

Background and aims Nutrients are important determinants of community assembly, yet the roles they play in structuring plant communities are still poorly understood. One inferential approach to understanding how environmental factors structure plant communities is examining the distribution of key functional traits among species of a community\—a community traitscape. Methods To better understand how nitrogen (N) and water availability structure grasslands, we measured N concentrations and isotope ratios for 366 herbaceous species in a mesic N-limited temperate grassland, Konza Prairie. We also compared foliar N concentrations and N isotopes between Konza species and a global dataset. Results Species that had either high foliar N concentrations or high δ15NL were not necessarily more or less abundant on the landscape nor more or less likely to be found in uplands, grazed areas, or burned areas. Apparently there are unique hot spots of high N availability at Konza and the typical non-Fabaceae Konza species occupies sites with greater N availability than found globally. Conclusions Although nascent, the Konza traitscapes suggest that plant diversity in nutrient-limited communities might be strongly dependent on high-nutrient availability sites that enable high-fertility species to persist in a matrix of low nutrient availability.

}, keywords = {LTER-KNZ, Community assembly, disturbance, Grasslands, Isotopes, Konza Prairie, Resource limitation}, doi = {10.1007/s11104-012-1141-7}, url = {https://link.springer.com/article/10.1007\%2Fs11104-012-1141-7}, author = {Craine, J.M. and Towne, E.G. and Ocheltree, T.W. and Jesse B. Nippert} } @article {KNZ001519, title = {Comparison of eggshell porosity and estimated gas flux between the brown-headed cowbird and two common hosts}, journal = {Journal of Avian Biology}, volume = {43}, year = {2012}, pages = {486 -490}, abstract = {

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

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1600-048X.2012.05705.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1600-048X.2012.05705.x}, author = {Jaeckle, W.B. and Kiefer, M. and Childs, B. and Harper, R.G. and Rivers, J.W. and Peer, B.D.} } @article {KNZ001492, title = {Contrasting bud bank dynamics of two co-occurring grasses in tallgrass prairie: implications for grassland dynamics}, journal = {Plant Ecology}, volume = {213}, year = {2012}, pages = {1437 -1448}, abstract = {

Because most shoot recruitment in perennial grasses occurs from belowground axillary buds, bud dynamics determine plant population dynamics and meristem limitation to population growth. Therefore, grassland vegetation responses to environmental change or disturbance may be influenced by interspecific differences in bud banks and the patterns and environmental controls of bud development and demography. We examined bud bank dynamics in Andropogon gerardii and Dichanthelium oligosanthes in tallgrass prairie by enumerating and classifying buds throughout 15 months to determine whether grass buds live for multiple years and accumulate; whether bud natality, dormancy and outgrowth are synchronous or variable; and whether bud bank dynamics differ between these co-occurring species. Andropogon gerardii (a C4 species) maintained a larger dormant bud bank, showed synchrony in bud development and transition to tiller, and its buds lived for multiple years. Thus, multiple previous years\’ bud cohorts contributed to recruitment. By contrast, D. oligosanthes (a C3 species) maintained a smaller dormant bud bank, had asynchronous bud development with active buds present year-round, and its buds lived for 1 year. Buds played different roles in the dynamics of each species, allowing A. gerardii to over-winter and recruit new spring tillers and D. oligosanthes to survive and recruit new tillers following summer dormancy. These differences in bud bank age structure, phenology, and dynamics between these species suggest greater demographic buffering and time-lag effects in A. gerardii populations. Interspecific differences in bud bank structure and dynamics may explain and help predict grassland responses to environmental change.

}, keywords = {LTER-KNZ, Meristem, Photosynthetic pathway, Plant demography, Plant population dynamics, Tiller recruitment, Vegetative reproduction}, doi = {10.1007/s11258-012-0102-9}, url = {https://link.springer.com/article/10.1007\%2Fs11258-012-0102-9}, author = {Ott, J.P. and D.C. Hartnett} } @article {KNZ001551, title = {Controls on bud activation and tiller initiation in C3 and C4 tallgrass prairie grasses: the role of light and nitrogen}, journal = {Botany}, volume = {90}, year = {2012}, pages = {1221 -1228}, abstract = {

Population dynamics of perennial grasses in tallgrass prairie ecosystems are strongly influenced by vegetative outgrowth from their belowground bud banks. We examined the role of light and nitrogen in regulating tiller initiation and tested an integrated model of controls on bud dormancy and activation in several C3 and C4 grasses. In addition, we assessed the interaction of nitrogen and light quantity and red \– far red spectral composition on tiller initiation. Belowground perennating organs of three C3 and three C4 species were grown under full light or dark conditions, amended with one of four nitrogen concentrations (0 to 350 ppm N). Dormant buds were also subjected to full light under different spectral compositions or to continuous darkness. Our results among C3 grasses support the integrated model as light and nitrogen played important and interacting roles in the regulation of bud banks. However, differences in responses among C4 grasses and a lack of light \× nitrogen interactions suggest that an alternative model may be necessary for this functional group. Our results provide predictions of responses to nitrogen enrichment or light imitations in prairie ecosystems due to interacting disturbances such as reduction in fire frequencies, alterations in grazing intensities, or climate change.

}, keywords = {LTER-KNZ, bud banks, C3 grasses, C4 grasses, perennial grasses, Tiller recruitment, Vegetative reproduction}, doi = {10.1139/b2012-091}, url = {http://www.nrcresearchpress.com/doi/10.1139/b2012-091}, author = {Williamson, M. and G.T. Wilson and D.C. Hartnett} } @article {KNZ001879, title = {Controls on Soil Organic Carbon Stocks and Turnover Among North American Ecosystems}, journal = {Ecosystems}, volume = {15}, year = {2012}, pages = {604 - 615}, keywords = {LTER-KNZ}, issn = {1432-9840}, doi = {10.1007/s10021-012-9534-2}, url = {http://link.springer.com/10.1007/s10021-012-9534-2}, author = {Frank, Douglas A. and Pontes, Alyssa W. and McFarlane, Karis J.} } @article {KNZ001549, title = {Coping with herbivory at the juvenile stage: Responses to defoliation and browsing in the African savanna tree Colophospermum mopane}, journal = {Journal of Tropical Ecology}, volume = {28}, year = {2012}, pages = {161 -169}, abstract = {

Responses of plants to herbivory are dependent on the type of damage and the ontogenetic stage of the plant. We compared the effects of stem pruning and defoliation on seedlings of Colophospermum mopane, an ecologically important tree species widely distributed in southern Africa. The growth of 160 greenhouse-grown juveniles were measured for 6-mo after germination and then 6-mo after treatments including 50\% defoliation, 100\% defoliation, 50\% stem pruning and controls. Pruning resulted in 30\% reductions in total leaf area, height and biomass. Partial defoliation resulted in 30\% reductions in total leaf area and plant biomass. However, complete defoliation resulted in a 30\% increase in biomass production, a doubling in leaf and lateral branch number, a 45\% reduction in leaf size, and no change in total leaf area. Thus, completely defoliated seedlings showed greater performance than those that were only partially defoliated, indicating that C. mopane has become adapted to the chronic and severe defoliation inflicted by Imbrasia belina caterpillars. Comparison of our results with other studies indicates that C. mopane seedlings are less herbivory-tolerant than adults and that pruning has more negative effects than defoliation. Thus, seedling browsers may constrain recruitment in C. mopane, influencing its population dynamics and abundance.

}, keywords = {LTER-KNZ, Botswana, browsing, defoliation, Herbivory, Plant{\textendash}herbivore interactions, savanna, seedlings, tree recruitment}, doi = {http://dx.doi.org/10.1017/S0266467412000028 }, url = {https://www.cambridge.org/core/journals/journal-of-tropical-ecology/article/coping-with-herbivory-at-the-juvenile-stage-responses-to-defoliation-and-stem-browsing-in-the-african-savanna-tree-colophospermum-mopane/5B519E0F1B9BD889D4905FD311257D9A}, author = {D.C. Hartnett and Ott, J.P. and Sebes, K. and Ditlhogo, M.} } @article {KNZ001757, title = {Changes in variability of soil moisture alter microbial community C and N resource use}, journal = {Soil Biology and Biochemistry}, volume = {43}, year = {2011}, pages = {1837 - 1847}, abstract = {

Grassland ecosystems contain ~12\% of global soil organic carbon (C) stocks and are located in regions where global climate change will likely alter the timing and size of precipitation events, increasing soil moisture variability. In response to increased soil moisture variability and other forms of stress, microorganisms can induce ecosystem-scale alterations in C and N cycling processes through alterations in their function. We explored the influence of physiological stress on microbial communities by manipulating moisture variability in soils from four grassland sites in the Great Plains, representing a precipitation gradient of 485-1003 mm y-1. Keeping water totals constant, we manipulated the frequency and size of water additions and dry down periods in these soils by applying water in two different, two-week long wetting-drying cycles in a 72-day laboratory incubation. To assess the effects of the treatments on microbial community function, we measured C mineralization, N dynamics, extracellular enzyme activities (EEA) and a proxy for substrate use efficiency. In soils from all four sites undergoing a long interval (LI) treatment for which added water was applied once at the beginning of each two-week cycle, 1.4-2.0 times more C was mineralized compared to soils undergoing a short interval (SI) treatment, for which four wetting events were evenly distributed over each two-week cycle. A proxy for carbon use efficiency (CUE) suggests declines in this parameter with the greater soil moisture stress imposed in LI soils from all four different native soil moisture regimes. A decline in CUE in LI soils may have been related to an increased effort by microbes to obtain N-rich organic substrates for use as protection against osmotic shock, consistent with EEA data. These results contrast with similar in situ studies of response to increased soil moisture variability and may indicate divergent autotrophic vs. heterotrophic responses to increased moisture variability. Increases in microbial N demand and decreases in microbial CUE with increased moisture variability observed in this study, regardless of the soils\&$\#$39; site of origin, imply that these systems may experience enhanced heterotrophic CO2 release and declines in plant-available N with climate change. This has particularly important implications for C budgets in these grasslands when coupled with the declines in net primary productivity reported in other studies as a result of increases in precipitation variability across the region.

}, keywords = {LTER-KNZ}, doi = {10.1016/j.soilbio.2011.04.020}, url = {https://www.sciencedirect.com/science/article/abs/pii/S0038071711001787?via\%3Dihub}, author = {Tiemann, L.K. and Billings, S.A.} } @article {KNZ001392, title = {Complexity in climate change impacts: An analytical framework for effects mediated by plant disease}, journal = {Plant Pathology}, volume = {60}, year = {2011}, pages = {15 -30}, abstract = {

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

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

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

}, keywords = {LTER-KNZ, Comparative, Comparison of potential with realized denitrification, DEA, denitrification, stream, Substrate-specific}, doi = {10.1007/s10533-010-9512-8}, url = {https://link.springer.com/article/10.1007\%2Fs10533-010-9512-8}, author = {Findlay, S.E.G. and Mulholland, P.J. and Hamilton, S. and Tank, J. and Bernot, M. and Burgin, A.J. and Crenshaw, C. and W. K. Dodds and Grimm, N. and W.H. McDowell and Potter, J. and Sobota, D.} } @mastersthesis {KNZ001305, title = {Calibrating vegetation cover and pollen assemblages in the Flint Hills of Kansas, USA}, volume = {MS Thesis}, year = {2010}, school = {Kansas State University}, type = {M.S. Thesis}, address = {Manhattan, KS. 73 pp}, abstract = {

The quantitative relationship between pollen assemblages in sediment and vegetation cover is largely unknown because many factors influence this relationship. This lack of quantitative relationship is particularly acute in grassland regions, where both past and future climate change have the potential to determine grassland composition and cover. The tool used to reconstruct past grassland cover is the relative abundance of distinct fossil pollen types preserved in sediment. However, the interpretation of grassland pollen assemblages as grassland vegetation types needs to be refined to improve these reconstructions. Using pollen found in the surface sediments from 24 artificially-constructed ponds in the Flint Hills ecoregion of Kansas, USA, I examined relationships between pollen and vegetation in the tallgrass prairie biome, which includes woody components. By comparing the pollen data to field-surveyed vegetation data and land cover classifications taken from Kansas Gap Analysis Program data, I correlated pollen and vegetation in this ecoregion. Pollen productivity estimates for Artemisia, Ambrosia, Asteraceae, Chenopodiaceae, Cornus, Fabaceae, Juniperus, Maclura, Poaceae, Populus, Quercus, and Salix were calculated via the Extended R-Value Model. Common pollen types identified in sediments are mostly herbaceous grassland plant species such as Poaceae, Artemisia, and Ambrosia, but woody plants such as Populus, Quercus, and Juniperus are also represented. PPEs have been calculated for four of these taxa in Europe, and values from the Flint Hills are higher. These are the first PPEs reported for eight of these taxa. This research will further advance quantitative vegetation reconstructions in the Great Plains of North America and refine interpretations of how climate change affects grasslands.

}, keywords = {LTER-KNZ, grassland, Kansas- Flint Hills, Pollen, prairie vegetation}, url = {http://hdl.handle.net/2097/4170}, author = {Commerford, J.L.} } @article {KNZ001303, title = {Climate change and cattle nutritional stress}, journal = {Global Change Biology}, volume = {16}, year = {2010}, pages = {2901 -2911}, abstract = {

Owing to the complex interactions among climate, plants, cattle grazing, and land management practices, the impacts of climate change on cattle have been hard to predict. Predicting future grassland ecosystem functioning relies on understanding how changes in climate alter the quantity of forage produced, but also forage quality. Plant protein, which is a function of plant nitrogen concentrations, and digestible energy limit the performance of herbivores when in short supply; moreover, deficiencies can be expensive to mitigate. To better understand how changes in temperature and precipitation would affect forage protein and energy availability, we analyzed over 21 000 measurements of cattle fecal chemistry acquired over 14 years in the continental US. Our analysis of patterns in forage quality among ecologically defined regions revealed that increasing temperature and declining precipitation decreased dietary crude protein and digestible organic matter for regions with continental climates. Within regions, quality also declined with increased temperature; however, the effects of precipitation were mixed. Any future increases in precipitation would be unlikely to compensate for the declines in forage quality that accompany projected temperature increases. As a result, cattle are likely to experience greater nutritional stress in the future. If these geographic patterns hold as a proxy for future climates, agriculture will require increased supplemental feeds or the consequence will be a decrease in livestock growth.

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1365-2486.2009.02060.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2486.2009.02060.x}, author = {Craine, J.M. and Elmore, A.J. and K.C. Olson and Tolleson, D.} } @article {KNZ001276, title = {Climate controls on grass culm production over a quarter century in a tallgrass prairie}, journal = {Ecology}, volume = {91}, year = {2010}, pages = {2132 -2140}, abstract = {

The flowering of grasses is a process critical to plant population dynamics and genetics, herbivore performance, and human health. To better understand the climate factors governing grass flowering, we analyzed the patterns of culm production over 25 years for three perennial tallgrass prairie species at Konza Prairie in Kansas, USA. The three species (Andropogon gerardii, Sorghastrum nutans, and Schizachyrium scoparium) all utilize the C4 photosynthetic pathway and were measured annually at the same locations for the past 25 years in an annually burned watershed. Culm production of all three species increased with higher growing-season soil moisture and precipitation but differed in their responses to water availability at different times during the growing season. Relative to Andropogon, Sorghastrum responded more to precipitation early in the growing season, and Schizachyrium responded more to precipitation late in the growing season. Flowering by each species also revealed a threshold relationship with late-season soil moisture at ~1 m depth, which likely is a proxy for season-long water balance. Although flowering can be influenced by conditions antecedent to the current growing season, neither soil moisture nor precipitation during the previous year influenced flowering over the 25-year period. Flowering culm production averaged 9\% and 7\% of total graminoid aboveground net primary production (ANPP) in the uplands and lowlands, respectively. Interannual variation in ANPP correlated only with Sorghastrum flowering, suggesting a predominant role of the species in ANPP responses to climate.

}, keywords = {LTER-KNZ}, doi = {10.1890/09-1242.1}, url = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/09-1242.1}, author = {Craine, J.M. and Towne, E.G. and Jesse B. Nippert} } @mastersthesis {KNZ001398, title = {Climate forcings and the nonlinear dynamics of grassland ecosystems}, volume = {MS Thesis}, year = {2010}, school = {University of Kansas}, type = {M.S. Thesis}, address = {Lawrence, KS}, abstract = {

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

}, keywords = {LTER-KNZ}, url = {http://hdl.handle.net/1808/6633}, author = {Petrie, M.} } @article {KNZ001316, title = {Community-level patterns of host use by the Brown-headed Cowbird (Molothrus ater), a generalist brood parasite}, journal = {Auk}, volume = {127}, year = {2010}, pages = {263 -273}, abstract = {

Quantifying community-level host use by generalist brood parasites is important because it provides a measure of the resources that parasites need for reproduction. During the 2002\–2007 breeding seasons, we quantified host use by the Brown-headed Cowbird (Molothrus ater) at Konza Prairie Biological Station in northeast Kansas. Overall, 54.4\% of nests (n = 2,621) of 22 passerine host species that typically accept parasitic eggs were parasitized, and parasitized nests contained an average of 1.9 \± 1.03 (SD) Brown-headed Cowbird eggs, nestlings, or both. Multiple parasitism was common on the study site in all years: 55.7\% of parasitized nests (n = 1,425) received \≥2 Brown-headed Cowbird eggs. The Bell\&$\#$39;s Vireo (Vireo bellii; 70.5\%) and the Dickcissel (Spiza americana; 69.6\%) were parasitized at a significantly greater rate than the Red-winged Blackbird (Agelaius phoeniceus, 21.9\%); collectively, these three species represented 85.8\% of potential host nests found in all years. The host preference of Brown-headed Cowbirds did not appear to shift among the three species and instead they exhibited a consistent preference for Dickcissel nests over the course of the breeding season and among years. Both the rate and the intensity of parasitism on Dickcissels were significantly lower during the present study than in one conducted several decades earlier at the same site. Our results indicate that cowbirds in northeast Kansas differentially parasitize hosts, that most cowbird eggs are laid in the nests of a small number of host species, and that the Dickcissel appears to be preferred over other hosts.

}, keywords = {LTER-KNZ, Agelaius phoeniceus, Bell{\textquoteright}s Vireo, brood parasitism, community-level parasitism, Dickcissel, host use, Molothrus ater, multiple parasitism, red-winged blackbird, Spiza americana, Vireo bellii}, doi = {10.1525/auk.2009.09053}, url = {https://academic.oup.com/auk/article/127/2/263/5148382}, author = {Rivers, J.W. and Jensen, W.E. and Kosciuch, K.L. and Rothstein, S.I.} } @article {KNZ001334, title = {Comparative genome scan detects host-related divergent selection in the grasshopper Hesperotettix viridis}, journal = {Molecular Ecology}, volume = {19}, year = {2010}, pages = {4012 -4028}, abstract = {

In this study, we used a comparative genome scan to examine patterns of population differentiation with respect to host plant use in Hesperotettix viridis, a Nearctic oligophagous grasshopper locally specialized on various Asteraceae including Solidago, Gutierrezia, and Ericameria. We identified amplified fragment length polymorphism (AFLP) loci with significantly elevated FST (outlier loci) in multiple different-host and same-host comparisons of populations while controlling for geographic distance. By comparing the number and identities of outlier loci in different-host vs. same-host comparisons, we found evidence of host plant-related divergent selection for some population comparisons (Solidago- vs. Gutierrezia-feeders), while other comparisons (Ericameria- vs. Gutierrezia-feeders) failed to demonstrate a strong role for host association in population differentiation. In comparisons of Solidago- vs. Gutierrezia-feeding populations, a relatively high number of outlier loci observed repeatedly in different-host comparisons (35\% of all outliers and 2.7\% of all 625 AFLP loci) indicated a significant role for host-related selection in contributing to overall genomic differentiation in this grasshopper. Mitochondrial DNA sequence data revealed a star-shaped phylogeny with no host- or geography-related structure, low nucleotide diversity, and high haplotype diversity, suggesting a recent population expansion. mtDNA data do not suggest a long period of isolation in separate glacial refugia but are instead more compatible with a single glacial refugium and more recent divergence in host use. Our study adds to research documenting heterogeneity in differentiation across the genome as a consequence of divergent natural selection, a phenomenon that may occur as part of the process of ecological speciation.

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1365-294X.2010.04792.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-294X.2010.04792.x}, author = {Apple, J.L. and Grace, T. and Anthony Joern and Amand, P. and Wisely, S.M.} } @article {KNZ001260, title = {Consumer return chronology alters recovery trajectory of stream ecosystem structure and function following drought}, journal = {Ecology}, volume = {91}, year = {2010}, pages = {1048 -1062}, abstract = {

Consumers are increasingly being recognized as important drivers of ecological succession, yet it is still hard to predict the nature and direction of consumer effects in nonequilibrium environments. We used stream consumer exclosures and large outdoor mesocosms to study the impact of macroconsumers (i.e., fish and crayfish) on recovery of intermittent prairie streams after drying. In the stream, macroconsumers altered system recovery trajectory by decreasing algal and macroinvertebrate biomass, primary productivity, and benthic nutrient uptake rates. However, macroconsumer influence was transient, and differences between exclosures and controls disappeared after 35 days. Introducing and removing macroconsumers after 28 days resulted mainly in changes to macroinvertebrates. In mesocosms, a dominant consumer (the grazing minnow Phoxinus erythrogaster) reduced macroinvertebrate biomass but had little effect on algal assemblage structure and ecosystem rates during recovery. The weak effect of P. erythrogaster in mesocosms, in contrast to the strong consumer effect in the natural stream, suggests that both timing and diversity of returning consumers are important to their overall influence on stream recovery patterns. Although we found that consumers significantly altered ecosystem structure and function in a system experiencing rapid changes in abiotic and biotic factors following disturbance, consumer effects diminished over time and trajectories converged to similar states with respect to primary producers, in spite of differences in consumer colonization history. Thus, consumer impacts can be substantial in recovering ecosystems and are likely to be dependent on the disturbance regime and diversity of the consumer community.

}, keywords = {LTER-KNZ}, doi = {10.1890/08-2168.1}, url = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/08-2168.1}, author = {Murdock, J.M. and K. B. Gido and W. K. Dodds and Bertrand, K.N. and M.R. Whiles} } @article {KNZ001356, title = {Contrasting ecosystem recovery on two soil textures: implications for carbon mitigation and grassland conservation}, journal = {Ecosphere}, volume = {1}, year = {2010}, pages = {5 -}, abstract = {

Understanding processes that promote or constrain ecosystem recovery from disturbance is needed to predict the restorative potential of degraded systems. We quantified a suite of ecosystem properties and processes across two chronosequences of restored grasslands on contrasting soil textures to test the hypothesis that restorations on silty clay loam soil would exhibit greater recovery of soil carbon (C) and nitrogen (N) pools and fluxes than on loamy fine sand because soil with higher clay content possesses a greater capacity to physico-chemically protect organic matter. Warm-season grass aboveground net primary productivity was similar between the two soil textures. Root biomass increased and root quality (as indexed by C:N ratio) decreased across both chronosequences. An asymptote in the accumulation of N in roots in the silty clay loam chronosequence resulted in wider C:N ratios of roots than in the loamy fine sand chronosequence. Total soil C (TC) and microbial biomass C (MBC) increased across the silty clay loam chronosequence at 21.2 and 5.7 g C\·m\−2\·yr\−1, respectively, and contained \>6 times the amount of C in large macroaggregates and nearly 3 times the aggregate mean weighted diameter (MWD) relative to cultivated soil following 15 yrs of restoration. In contrast, there were no changes in TC, MBC, or MWD in the loamy fine sand chronosequence. Total and microbial biomass N increased at 2.0 and 0.27 g N\·m\−2\·yr\−1, respectively, across the silty clay loam chronosequence, and restored soil contained nearly 6 times large macroaggregate N than cultivated soil following 15 yrs of restoration. Potential net N mineralization rates declined with years of grass establishment in both soil textures, but overall rates were lower in the silty clay loam soil relative to the loamy fine sand, which was attributed to lower quality root systems, more improved soil structure, and larger microbial biomass. Thus, the potential for restored agricultural lands to mitigate CO2 emissions over the short term cannot be generalized across all soils. Lastly, the low restorative potential of cultivated loamy fine sand soil through grassland restoration within two decades (relevant to many conservation programs) underscores the need to prioritize preservation of remnant sand prairies.

}, keywords = {LTER-KNZ}, doi = {10.1890/ES10-00004.1 }, url = {https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/ES10-00004.1}, author = {S.G. Baer and Meyer, C.K. and E.M. Bach and Klopf, R.P. and Six, J.} } @article {KNZ001424, title = {Contrasting trait responses in plant communities to experimental and geographic variation in precipitation}, journal = {New Phytologist}, volume = {188}, year = {2010}, pages = {565 -575}, abstract = {

\•Patterns of precipitation are likely to change significantly in the coming century, with important but poorly understood consequences for plant communities. Experimental and correlative studies may provide insight into expected changes, but little research has addressed the degree of concordance between these approaches. \•We synthesized results from four experimental water addition studies with a correlative analysis of community changes across a large natural precipitation gradient in the United States. We investigated whether community composition, summarized with plant functional traits, responded similarly to increasing precipitation among studies and sites. \•In field experiments, increased precipitation favored species with small seed size, short leaf life span and high leaf nitrogen (N) concentration. However, with increasing precipitation along the natural gradient, community composition shifted towards species with higher mean seed mass, longer leaf life span and lower leaf N concentrations. \•The differences in temporal and spatial scale of experimental manipulations and natural gradients may explain these contrasting results. Our results highlight the complexity of responses to climate change, and suggest that transient dynamics may not reflect long-term shifts in functional diversity and community composition. We propose a model of community change that incorporates these differences between short- and long-term responses to climate change.

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1469-8137.2010.03382.x}, url = {https://nph.onlinelibrary.wiley.com/doi/full/10.1111/j.1469-8137.2010.03382.x}, author = {Sandel, B. and Goldstein, L.J. and Kraft, N.J. and Okie, J.G. and Shuldman, M.I. and Ackerly, D.D. and Cleland, E.E. and K.N. Suding} } @mastersthesis {KNZ001394, title = {Controls on bud activation and tiller initiation in tallgrass prairie: The effect of light and nitrogen}, volume = {MS Thesis}, year = {2010}, pages = {1 -52}, school = {Oklahoma State University}, type = {M.S. Thesis}, address = {Stillwater, OK}, abstract = {

Chapter 1: Perennial grass populations in tallgrass prairie ecosystems are maintained primarily through vegetative outgrowth from their belowground bud banks. Resources in these ecosystems that have been found to limit plant productivity include nitrogen and light. I tested the Tomlinson and O\&$\#$39;Connor (2004) theory, on the interactions of two environmental cues, nitrogen and light quantity, and the roles they have on bud outgrowth and tiller initiation in six perennial grass species in two functional groups (C 3 and C 4 photosynthetic pathways). I hypothesized that (1) an interaction between nitrogen and light availability regulated bud activation and tiller emergence in the two functional groups (C 3 species and C 4 species), (2) nitrogen would have the largest effect on the activation of buds, and (3) responses to the two environmental cues would differ between the two functional groups. Environmental growth chambers were used to conduct all studies, plants received one of three NH 4 NO 3 amendments or water (control), and were placed in a light treatment chamber or a dark (control) chamber. Strong interactions between nitrogen and light influenced bud outgrowth in the C c species, but not in the C 4 species. When I assessed the impacts of nitrogen as a key cue in tiller initiation in all six species, C 3 species responded favorably to N, while C 4 species did not. These results indicate that another abiotic environmental cue may be influencing the C 4 species. The results of this study suggest that environmental cues such as these that impact belowground bud bank dynamics in the tallgrass prairie have to potential to significantly impact grassland dynamics in response to current and future global changes. Chapter 2: Three species of C 3 grasses and three species of C 4 grasses were studied to test a proposed theory (Tomlinson and O\&$\#$39;Connor 2004), to determine the role that light spectral quality (R:FR) and light quantity have on belowground bud outgrowth. I hypothesized that (1) R:FR will be an important cue in the regulation of bud bank dynamics, (2) reductions in light quantity due to litter accumulation will significantly reduce bud outgrowth, and (3) the response to the two factors will not be consistent across the two functional groups. Environmental growth chambers were used to conduct all study treatments. Plants were placed in chambers under one of three light treatments: light, reduced R:FR, or a full dark (control). To assess the effects of light availability under natural conditions, litter was used to reduce light availability in the C 4 species. Light spectral quality and quantity elicited species-specific responses in both of the functional groups. A suppression in bud outgrowth in response to R:FR reductions were observed in four of the six species. Alterations to light quantity due to litter accumulation did not reduce bud outgrowth, but a reduction in R:FR did, suggesting that light spectral quality is a more important regulator of bud dormancy and outgrowth than light intensity. Surprisingly, the response to light spectral quality and quantity were consistent across both functional groups. As we continue to seek answers to enhance rangeland quality, assessing how environmental cues are interacting may be a stronger predictor of how rangelands will respond to current and future global changes, than assessing the cues individually.

}, keywords = {LTER-KNZ}, url = {http://hdl.handle.net/11244/9577}, author = {Williamson, M.M.} } @article {KNZ001323, title = {Centimeter-scale stream substratum heterogeneity and metabolic rates}, journal = {Hydrobiologia}, volume = {623}, year = {2009}, pages = {53 -62}, abstract = {

Spatial heterogeneity of substrata in streams may influence dissolved oxygen (O2) transport and nutrient forms. We studied the relationship between scales of substratum heterogeneity and O2. Heterogeneous systems could have greater respiration rates as a result of increased interfacial surfaces in the biogeochemically active areas between oxic and anoxic zones. We used grids with twelve 7 \× 3.5 cm cells; half the cells were filled with sand and the other half with gravel to quantify the effect of centimeter-scale heterogeneity on respiration. The sand and gravel cells were arranged within the grids to give low, medium, and high heterogeneity. Grids were incubated for 15\–17 days in a prairie stream, and then whole grid respiration was analyzed in closed recirculating chambers. Depth to anoxia and substratum metabolism were calculated from O2 microelectrode profiles measured in each cell of the grid and compared with data from natural stream transects from agricultural, urban, and prairie land use types. Shannon\–Weaver (H\′) diversity and \“probability of change\” indices were also used to compare heterogeneity of the grids to the natural stream transects. No significant differences were found among grid heterogeneity levels for respiration rate, but the anoxic interface was deeper in the gravel of higher heterogeneity grids, probably due to greater transport rates of O2 in the coarse-grained substratum. The H\′ and probability of change indices indicated that the grids had levels of heterogeneity within the range of real streams. Grid depth to anoxia and substratum metabolism rates were similar to those found in streams, though less variable. In streams, H\′ and probability of change values showed a slight difference among land use types, with some urban and agricultural sites displaying very low heterogeneity.

}, keywords = {LTER-KNZ, Dissolved oxygen, nutrients, O2 microelectrodes, stream, Substratum}, doi = {10.1007/s10750-008-9647-y}, url = {https://link.springer.com/article/10.1007\%2Fs10750-008-9647-y}, author = {Wilson, K.C. and W. K. Dodds} } @inbook {KNZ001256, title = {Challenges and approaches to statistical design and inference in high dimensional investigations}, booktitle = {Plant Systems Biology, Methods in Molecular Biology Series}, year = {2009}, pages = {181 -206}, publisher = {The Humana Press Inc}, organization = {The Humana Press Inc}, address = {Totowa, NJ}, abstract = {

Advances in modern technologies have facilitated high-dimensional experiments (HDEs) that generate tremendous amounts of genomic, proteomic, and other \“omic\” data. HDEs involving whole-genome sequences and polymorphisms, expression levels of genes, protein abundance measurements, and combinations thereof have become a vanguard for new analytic approaches to the analysis of HDE data. Such situations demand creative approaches to the processes of statistical inference, estimation, prediction, classification, and study design. The novel and challenging biological questions asked from HDE data have resulted in many specialized analytic techniques being developed. This chapter discusses some of the unique statistical challenges facing investigators studying high-dimensional biology and describes some approaches being developed by statistical scientists. We have included some focus on the increasing interest in questions involving testing multiple propositions simultaneously, appropriate inferential indicators for the types of questions biologists are interested in, and the need for replication of results across independent studies, investigators, and settings. A key consideration inherent throughout is the challenge in providing methods that a statistician judges to be sound and a biologist finds informative.

}, keywords = {LTER-KNZ, FDR, genomics, high-dimensional, microarray, multiple testing, statistics}, doi = {10.1007/978-1-60327-563-7_9}, url = {https://link.springer.com/protocol/10.1007\%2F978-1-60327-563-7_9}, author = {Gadbury, G.L. and Garrett, K.A. and Allison, D.B.}, editor = {Belostotsky, D.A.} } @article {KNZ001243, title = {Characterization of the water soluble soil organic pool following the rewetting of dry soil in a drought-prone tallgrass prairie}, journal = {Soil Biology \& Biochemistry}, volume = {41}, year = {2009}, pages = {21 -28}, abstract = {

To better understand the nature of the C flush that follows the rewetting of dry soil, we chemically characterized the water soluble pools following rewetting of soil dried to several different water potentials. To assess the impact that historical soil water status has on the size of the rewetting labile soluble pool, a laboratory water stress gradient was applied to soils that were collected from drought-prone and irrigated tallgrass prairie soils. In the laboratory, soils were either incubated at \−33 kPa or dried steadily over a 0.6, 1, 2, or 3 day period to \−1.5, \−4, \−15, and \−45 MPa respectively. On the 4th day, samples were wetted back to \−33 kPa and immediately assayed for soluble, microbial, or respiratory pools of carbon. After extraction, samples were also assayed using NMR, GC\–MS, and LC\–MS to assess carbohydrate, amino acid, osmolyte and sugar pools. The greater the degree of drying before rewetting was associated with greater concentrations of microbial, soluble and respiratory pools of carbon, increasing by 50, 400 and 250\%, respectively, in the most water stressed compared to continuously moist soil. Compared to drought-prone soils, the amount of soluble C released as a result of rewetting was 30 to 50\% greater in soils that were irrigated for 11 years. The pool of organics was not completely characterized and only small amounts of TBDMS and TMS derived compounds accounting for 2\–4\% of the soluble C pool were detected. In contrast, oligosaccharides constituted approximately 20\–25\% of the sample C. Our results suggest that the flush of C following wetting of a dry soil is not dominated by common microbial osmolytes (e.g. proline, glycine betaine, ectoine, glycerol, mannitol, trehalose). In light of this finding more research is needed to better understand the adaptations that microbial communities utilize to respond to the rewetting of dried soil.

}, keywords = {LTER-KNZ, Compatible solutes, Drying-rewetting, GC{\textendash}MS, Microbial response to water stress, NMR}, doi = {10.1016/j.soilbio.2008.08.013}, url = {https://www.sciencedirect.com/science/article/abs/pii/S0038071708002800?via\%3Dihub}, author = {Williams, M.A. and Xia, K.} } @article {KNZ001268, title = {CO2 distribution in groundwater and the impact of groundwater extraction on the global C cycle}, journal = {Chemical Geology}, volume = {264}, year = {2009}, pages = {328 -336}, abstract = {

Growing population and wealth, agricultural expansion, changing land use, and mechanized irrigation increase the demand on water resources. Groundwater accounts for about 20\% of global water use, with agriculture the largest consumer. Groundwater CO2 partial pressures are typically \∼ 10\–100 times higher than atmospheric, so CO2 degassing is an unavoidable consequence of groundwater extraction. For regional studies, very good estimates of groundwater CO2 in clastic aquifers can be calculated for temperate-climate regions from: log10(pCO2)=log10(HCO\−3)\−pH+7.749 where the constant is the sum of the negative logarithm (base 10) of the Henry\&$\#$39;s Law constant for CO2 and first association constant for H2CO3 at 13 \°C, and titration alkalinity can be substituted for activity of HCO3\−. Groundwater CO2 is not uniformly distributed in groundwater, being most variable near the water table, lowest at intermediate depth, and highest in deep aquifers where non-potable water is typical. Geochemical speciation modeling is required to assess CO2 released when groundwater equilibrates with the atmosphere. A suite of potable water types were modeled for this purpose, with the result that current groundwater production is estimated to release \∼ 0.01 to 0.03 Pg C year\− 1, similar to CO2 from volcanic emissions and \∼ 200 times less than other human-sourced CO2 emissions. Determination of dissolved CO2 depends on accuracy of pH measurements: CO2 released due to groundwater use may be underestimated if reported pH measurements do not represent in situ pH.

}, keywords = {LTER-KNZ, Carbon dioxide, CO2, Global carbon cycle, groundwater, Groundwater extraction}, doi = {10.1016/j.chemgeo.2009.03.018}, url = {https://www.sciencedirect.com/science/article/abs/pii/S0009254109001399?via\%3Dihub}, author = {G. L. Macpherson} } @article {KNZ001258, title = {Connectivity of the American agricultural landscape: Assessing the national risk of crop pest and disease spread}, journal = {Bioscience}, volume = {59}, year = {2009}, pages = {141 -151}, abstract = {

More than two-thirds of cropland in the United States is devoted to the production of just four crop species\—maize, wheat, soybeans, and cotton\—raising concerns that homogenization of the American agricultural landscape could facilitate widespread disease and pest outbreaks, compromising the national food supply. As a new component in national agricultural risk assessment, we employed a graph-theoretic approach to examine the connectivity of these crops across the United States. We used county crop acreage to evaluate the landscape resistance to transmission\—the degree to which host availability limits spread in any given region\—for pests or pathogens dependent on each crop. For organisms that can disperse under conditions of lower host availability, maize and soybean are highly connected at a national scale, compared with the more discrete regions of wheat and cotton production. Determining the scales at which connectivity becomes disrupted for organisms with different dispersal abilities may help target rapid-response regions and the development of strategic policies to enhance agricultural landscape heterogeneity.

}, keywords = {LTER-KNZ, geographic information systems, graph theory, Invasive species, landscape connectivity, networks}, doi = {https://doi.org/10.1525/bio.2009.59.2.7}, url = {https://academic.oup.com/bioscience/article/59/2/141/228297}, author = {Margosian, M.L. and Garrett, K.A. and Hutchinson, J.M.S. and With, K.A.} } @article {KNZ001240, title = {Consequences of climate variability for the performance of bison in tallgrass prairie}, journal = {Global Change Biology}, volume = {15}, year = {2009}, pages = {772 -779}, abstract = {

Climate variability is a major structuring factor in grassland ecosystems, yet there is great uncertainty in how changes in precipitation affect grazing herbivores. We determined how interannual variation in the timing and magnitude of precipitation affected the weight gain of free-roaming bison in their first and second year. Bison weights were analyzed for 14 years for Konza Prairie, Kansas, and 12 years for Tallgrass Prairie Preserve, Oklahoma. Greater late-summer precipitation increased bison weight gain. For every 100 mm precipitation, weight gain increased 6.4\–15.3 kg depending on age classes and site. In contrast, greater midsummer precipitation decreased weight gain. For every additional 100 mm precipitation, weight decreased 9.7\–17.3 kg depending on age class and site. The decreased weight gain of bison with greater midsummer precipitation was associated with increased grass stem production during the period for each of three dominant grasses at Konza Prairie. Although greater stem production increases the quantity of aboveground biomass, it should decrease the overall nutritional quality of biomass to grazers, which would reduce weight gain. With offsetting effects of mid- and late-summer precipitation on weight gain, these results show that predicting the effects of climate change on grazers must incorporate both the timing and magnitude of changes in precipitation and their effects on both the quantity and quality of biomass.

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1365-2486.2008.01769.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2486.2008.01769.x}, author = {Craine, J.M. and Towne, E.G. and Anthony Joern and Hamilton, R.G.} } @article {KNZ001242, title = {Conservation of nitrogen increases with precipitation across a major grassland gradient in the Central Great Plains of North America}, journal = {Oecologia}, volume = {159}, year = {2009}, pages = {571 -581}, abstract = {

Regional analyses and biogeochemical models predict that ecosystem N pools and N cycling rates must increase from the semi-arid shortgrass steppe to the sub-humid tallgrass prairie of the Central Great Plains, yet few field data exist to evaluate these predictions. In this paper, we measured rates of net N mineralization, N in above- and belowground primary production, total soil organic matter N pools, soil inorganic N pools and capture in resin bags, decomposition rates, foliar 15N, and N use efficiency (NUE) across a precipitation gradient. We found that net N mineralization did not increase across the gradient, despite more N generally being found in plant production, suggesting higher N uptake, in the wetter areas. NUE of plants increased with precipitation, and δ15N foliar values and resin-captured N in soils decreased, all of which are consistent with the hypothesis that N cycling is tighter at the wet end of the gradient. Litter decomposition appeared to play a role in maintaining this regional N cycling trend: litter decomposed more slowly and released less N at the wet end of the gradient. These results suggest that immobilization of N within the plant\–soil system increases from semi-arid shortgrass steppe to sub-humid tallgrass prairie. Despite the fact that N pools increase along a bio-climatic gradient from shortgrass steppe to mixed grass and tallgrass prairie, this element becomes relatively more limiting and is therefore more tightly conserved at the wettest end of the gradient. Similar to findings from forested systems, our results suggest that grassland N cycling becomes more open to N loss with increasing aridity.

}, keywords = {LTER-KNZ, Grasslands, Net nitrogen mineralization, Nitrogen pools, Nitrogen use efficiency, Regional trends}, doi = {10.1007/s00442-008-1229-1}, url = {https://link.springer.com/article/10.1007\%2Fs00442-008-1229-1}, author = {McCulley, R.L. and Burke, I.C. and Lauenroth, W.K.} } @article {KNZ001239, title = {Contingent productivity responses to more extreme rainfall regimes across a grassland biome}, journal = {Global Change Biology}, volume = {15}, year = {2009}, pages = {2894 -2904}, abstract = {

Climate models predict, and empirical evidence confirms, that more extreme precipitation regimes are occurring in tandem with warmer atmospheric temperatures. These more extreme rainfall patterns are characterized by increased event size separated by longer within season drought periods and represent novel climatic conditions whose consequences for different ecosystem types are largely unknown. Here, we present results from an experiment in which more extreme rainfall patterns were imposed in three native grassland sites in the Central Plains Region of North America, USA. Along this 600 km precipitation\–productivity gradient, there was strong sensitivity of temperate grasslands to more extreme growing season rainfall regimes, with responses of aboveground net primary productivity (ANPP) contingent on mean soil water levels for different grassland types. At the mesic end of the gradient (tallgrass prairie), longer dry intervals between events led to extended periods of below-average soil water content, increased plant water stress and reduced ANPP by 18\%. The opposite response occurred at the dry end (semiarid steppe), where a shift to fewer, but larger, events increased periods of above-average soil water content, reduced seasonal plant water stress and resulted in a 30\% increase in ANPP. At an intermediate mixed grass prairie site with high plant species richness, ANPP was most sensitive to more extreme rainfall regimes (70\% increase). These results highlight the inherent complexity in predicting how terrestrial ecosystems will respond to forecast novel climate conditions as well as the difficulties in extending inferences from single site experiments across biomes. Even with no change in annual precipitation amount, ANPP responses in a relatively uniform physiographic region differed in both magnitude and direction in response to within season changes in rainfall event size/frequency.

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1365-2486.2009.01961.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2486.2009.01961.x}, author = {Heisler-White, J.L. and John M. Blair and Kelly, E.F. and Harmoney, K. and Alan K. Knapp} } @mastersthesis {KNZ001279, title = {Controls of aboveground net primary production in mesic savanna grasslands: An inter-hemispheric comparison}, volume = {MS Thesis}, year = {2009}, pages = {1 -50}, school = {Colorado State University}, type = {M.S. Thesis}, address = {Fort Collins, CO}, abstract = {

Patterns and controls of annual aboveground net primary productivity (ANPP) are fundamental metrics of ecosystem functioning. It is generally assumed, but rarely tested, that determinants of ANPP in one region within a biome will operate similarly throughout that biome, as long as physiognomy and climate are broadly consistent. We tested this assumption by quantifying ANPP responses to fire, grazing history, and nitrogen (N) addition in North American (NA) and South African (SA) savanna grasslands. We found that total ANPP responded in generally consistent ways to fire, grazing history, and N addition on both continents. Annual fire in both NA and SA consistently stimulated total ANPP (28\–100\%) relative to unburned treatments at sites with deep soils, and had no effect on ANPP in sites with shallow soils. Fire did not affect total ANPP in sites with a recent history of grazing, regardless of whether a single or a diverse suite of large herbivores was present. N addition interacted strongly and consistently with fire regime in both NA and SA. In annually burned sites that were not grazed, total ANPP was stimulated by N addition (29\–39\%), but there was no effect of N fertilization in the absence of fire. In contrast, responses in forb ANPP to fire and grazing were somewhat divergent across this biome. Annual fire in NA reduced forb ANPP, whereas grazing increased forb ANPP, but neither response was evident in SA. Thus, despite a consistent response in total ANPP, divergent responses in forb ANPP suggest that other aspects of community structure and ecosystem functioning differ in important ways between these mesic savanna grasslands.

}, keywords = {LTER-KNZ, ANPP, fire, Grasslands, Grazing, nitrogen, Savannas}, doi = {10.1007/s10021-009-9273-1}, author = {Buis, G.} } @article {KNZ001259, title = {Controls of aboveground net primary production in mesic savanna grasslands: An inter-hemispheric comparison}, journal = {Ecosystems}, volume = {12}, year = {2009}, pages = {982 -995}, abstract = {

Patterns and controls of annual aboveground net primary productivity (ANPP) are fundamental metrics of ecosystem functioning. It is generally assumed, but rarely tested, that determinants of ANPP in one region within a biome will operate similarly throughout that biome, as long as physiognomy and climate are broadly consistent. We tested this assumption by quantifying ANPP responses to fire, grazing history, and nitrogen (N) addition in North American (NA) and South African (SA) savanna grasslands. We found that total ANPP responded in generally consistent ways to fire, grazing history, and N addition on both continents. Annual fire in both NA and SA consistently stimulated total ANPP (28\–100\%) relative to unburned treatments at sites with deep soils, and had no effect on ANPP in sites with shallow soils. Fire did not affect total ANPP in sites with a recent history of grazing, regardless of whether a single or a diverse suite of large herbivores was present. N addition interacted strongly and consistently with fire regime in both NA and SA. In annually burned sites that were not grazed, total ANPP was stimulated by N addition (29\–39\%), but there was no effect of N fertilization in the absence of fire. In contrast, responses in forb ANPP to fire and grazing were somewhat divergent across this biome. Annual fire in NA reduced forb ANPP, whereas grazing increased forb ANPP, but neither response was evident in SA. Thus, despite a consistent response in total ANPP, divergent responses in forb ANPP suggest that other aspects of community structure and ecosystem functioning differ in important ways between these mesic savanna grasslands.

}, keywords = {LTER-KNZ, ANPP, fire, Grasslands, Grazing, nitrogen, Savannas}, doi = {10.1007/s10021-009-9273-1}, url = {https://link.springer.com/article/10.1007\%2Fs10021-009-9273-1}, author = {Buis, G.M. and John M. Blair and Burkepile, D.E. and Burns, C.E. and Chamberlain, A.J. and Chapman, P. and Scott. L. Collins and Fynn, R.W.S. and Govender, N. and Kirkman, K. and M.D. Smith and Alan K. Knapp} } @article {KNZ001351, title = {Cross-site comparison of herbivore impact on nitrogen availability in grasslands: the role of plant nitrogen concentration}, journal = {Oikos}, volume = {118}, year = {2009}, pages = {1613 -1622}, abstract = {

Herbivores may influence the nitrogen (N) recycling rates and consequently increase or decrease the productivity of grasslands. Plant N concentration emerged as a critical parameter to explain herbivore effects from several conceptual models, which predict that herbivores decrease soil N availability when plant N concentration is low whereas they increase it when plant N concentration is high (Hobbs 1996, Ritchie et al. 1998, Pastor et al. 2006). However, a broader cross-site comparison among published studies to test these predictions is hampered by the different methodologies used to measure soil N availability or a proxy thereof, and a lack of measurements of plant N concentration. Therefore it remains unclear whether these model predictions are generally valid across a range of grasslands. We tested whether there is a relationship between plant N concentration and herbivore impact on soil N availability (measured with resin bags) with a study of replicate 6\–8 year old exclosures (with an unfenced control) of vertebrate herbivores (\>1 kg) established at each of seven grassland sites in North America and Europe. Contrary to model predictions, we found a negative relationship between the effect of herbivores on resin bag soil N availability and plant N concentration. Our study confirms the importance of plant N concentration as a predictor of herbivore effect on soil N availability across grasslands, but contradicts the models. A possible explanation may be that the results represent a transient situation as the exclosures were relatively young whereas the models may refer to an equilibrium state. Simultaneous measurements of both plant N concentration and herbivore effect on soil N availability from more grassland sites, preferably with contrasting plant N concentrations and including exclosures of different ages, should resolve the contrast between model predictions and our field measurements.

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1600-0706.2009.17199.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1600-0706.2009.17199.x}, author = {E.S. Bakker and Knops, J.M.H. and Milchunas, D.G. and Ritchie, M.E. and Olff, H.} } @article {KNZ001174, title = {Changes in grassland ecosystem function due to extreme rainfall events: implications for responses to climate change}, journal = {Global Change Biology}, volume = {14}, year = {2008}, pages = {1600 -1608}, abstract = {

Climate change is causing measurable changes in rainfall patterns, and will likely cause increases in extreme rainfall events, with uncertain implications for key processes in ecosystem function and carbon cycling. We examined how variation in rainfall total quantity (Q), the interval between rainfall events (I), and individual event size (SE) affected soil water content (SWC) and three aspects of ecosystem function: leaf photosynthetic carbon gain (inline image), aboveground net primary productivity (ANPP), and soil respiration (inline image). We utilized rainout shelter-covered mesocosms (2.6 m3) containing assemblages of tallgrass prairie grasses and forbs. These were hand watered with 16 I\×Q treatment combinations, using event sizes from 4 to 53 mm. Increasing Q by 250\% (400\–1000 mm yr\−1) increased mean soil moisture and all three processes as expected, but only by 20\–55\% (P\≤0.004), suggesting diminishing returns in ecosystem function as Q increased. Increasing I (from 3 to 15 days between rainfall inputs) caused both positive (inline image) and negative (inline image) changes in ecosystem processes (20\–70\%, P\≤0.01), within and across levels of Q, indicating that I strongly influenced the effects of Q, and shifted the system towards increased net carbon uptake. Variation in SE at shorter I produced greater response in soil moisture and ecosystem processes than did variation in SE at longer I, suggesting greater stability in ecosystem function at longer I and a priming effect at shorter I. Significant differences in ANPP and inline image between treatments differing in I and Q but sharing the same SE showed that the prevailing pattern of rainfall influenced the responses to a given event size. Grassland ecosystem responses to extreme rainfall patterns expected with climate change are, therefore, likely to be variable, depending on how I, Q, and SE combine, but will likely result in changes in ecosystem carbon cycling.

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1365-2486.2008.01605.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2486.2008.01605.x}, author = {Fay, P.A. and Kaufman, D.M. and Jesse B. Nippert and Carlisle, J.D. and Harper, C.W.} } @inbook {KNZ001198, title = {Climate change and plant disease risk}, booktitle = {Global Climate Change and Extreme Weather Events: Understanding the Contributions to Infectious Disease Emergence}, year = {2008}, pages = {143 -155}, publisher = {National Academies Press}, organization = {National Academies Press}, abstract = {

Research in the effects of climate change on plant disease continues to be limited, but some striking progress has been made. At the genomic level, advances in technologies for the high-throughput analysis of gene expression have made it possible to begin discriminating responses to different biotic and abiotic stressors and potential trade-offs in responses. At the scale of the individual plant, enough experiments have been performed to begin synthesizing the effects of climate variables on infection rates, though pathosystemspecific characteristics make synthesis challenging. Models of plant disease have now been developed to incorporate more sophisticated climate predictions. At the population level, the adaptive potential of plant and pathogen populations may prove to be one of the most important predictors of the magnitude of climate change effects. Ecosystem ecologists are now addressing the role of plant disease in ecosystem processes and the challenge of scaling up from individual infection probabilities to epidemics and broader impacts.

}, keywords = {LTER-KNZ}, url = {https://vtechworks.lib.vt.edu/handle/10919/68091}, author = {Garrett, K.A.} } @article {KNZ001166, title = {Coexisting generalist herbivores occupy unique nutritional feeding niches}, journal = {Proceedings of the National Academy of Sciences}, volume = {105}, year = {2008}, pages = {1977 -1982}, abstract = {

A mainstay of ecological theory and practice is that coexisting species use different resources, leading to the local development of biodiversity. However, a problem arises for understanding coexistence of multiple species if they share critical resources too generally. Here, we employ an experimental framework grounded in nutritional physiology to show that closely related, cooccurring and generalist-feeding herbivores (seven grasshopper species in the genus Melanoplus; Orthoptera: Acrididae) eat protein and carbohydrate in different absolute amounts and ratios even if they eat the same plant taxa. The existence of species-specific nutritional niches provides a cryptic mechanism that helps explain how generalist herbivores with broadly overlapping diets might coexist. We also show that performance by grasshoppers allowed to mix their diets and thus regulate their protein\–carbohydrate intake matched optimal performance peaks generated from no-choice treatments. These results indicate the active nature of diet selection to achieve balanced diets and provide buffering capacity in the face of variable food quality. Our empirical findings and experimental approach can be extended to generate and test predictions concerning the intensity of biotic interactions between species, the relative abundance of species, yearly fluctuations in population size, and the nature of interactions with natural enemies in tritrophic niche space.

}, keywords = {LTER-KNZ, Biodiversity, Competition, geometric framework, physiological ecology, resource partitioning}, doi = {10.1073/pnas.0711870105}, url = {https://www.pnas.org/content/105/6/1977}, author = {Behmer, S.T. and Anthony Joern} } @article {KNZ001207, title = {Comparing ecosystem goods and services provided by restored and native lands}, journal = {BioScience}, volume = {58}, year = {2008}, pages = {837 -845}, abstract = {

We determined the relative benefits for eight categories of ecosystem goods and services associated with native and restored lands across the conterminous United States. Less than 10\% of most native US ecosystems remain, and the proportion that is restored varies widely by biome. Restored lands offer 31\% to 93\% of native land benefits within a decade after restoration, with restored wetlands providing the most economic value and deserts providing the least. Restored ecosystems that recover rapidly and produce valuable commodities return a higher proportion of total value. The relative values of the benefits provided by restoration vary both by biome and by the ecosystem goods and services of interest. Our analysis confirms that conservation should be the first priority, but that restoration programs across broad geographic regions can have substantial value. \“No net loss\” policies should recognize that restored lands are not necessarily equivalent to native areas with regard to estimated ecosystem benefits.

}, keywords = {LTER-KNZ, conservation, ecosystem goods, ecosystem services, ecosystem valuation, restoration}, doi = {10.1641/B580909}, url = {https://academic.oup.com/bioscience/article/58/9/837/250939}, author = {W. K. Dodds and Wilson, K.C. and Rehmeier, R.L. and Knight, G.L. and Wiggam, S. and Falke, J.A. and Dalgleish, H.J. and Bertrand, K.N.} } @article {KNZ001162, title = {Comparison of damage to native and exotic tallgrass prairie plants by natural enemies}, journal = {Plant Ecology}, volume = {198}, year = {2008}, pages = {197 -210}, abstract = {

We surveyed the prevalence and amount of leaf damage related to herbivory and pathogens on 12 pairs of exotic (invasive and noninvasive) and ecologically similar native plant species in tallgrass prairie to examine whether patterns of damage match predictions from the enemy release hypothesis. We also assessed whether natural enemy impacts differed in response to key environmental factors in tallgrass prairie by surveying the prevalence of rust on the dominant C4 grass, Andropogon gerardii, and its congeneric invasive exotic C4 grass, A. bladhii, in response to fire and nitrogen fertilization treatments. Overall, we found that the native species sustain 56.4\% more overall leaf damage and 83.6\% more herbivore-related leaf damage when compared to the exotic species. Moreover, we found that the invasive exotic species sustained less damage from enemies relative to their corresponding native species than the noninvasive exotic species. Finally, we found that burning and nitrogen fertilization both significantly increased the prevalence of rust fungi in the native grass, while rust fungi rarely occurred on the exotic grass. These results indicate that reduced damage from enemies may in part explain the successful naturalization of exotic species and the spread of invasive exotic species in tallgrass prairie.

}, keywords = {LTER-KNZ, Enemy release hypothesis, grassland, Invasiveness, Leaf damage, Rust fungi}, doi = {10.1007/s11258-008-9395-0}, url = {https://link.springer.com/article/10.1007\%2Fs11258-008-9395-0}, author = {Han, X. and Dend, S.P. and Garrett, K.A. and Fang, L. and M.D. Smith} } @article {KNZ001187, title = {Consequences of more extreme precipitation regimes for terrestrial ecosystems}, journal = {BioScience}, volume = {58}, year = {2008}, pages = {811 -821}, abstract = {

mplification of the hydrological cycle as a consequence of global warming is forecast to lead to more extreme intra-annual precipitation regimes characterized by larger rainfall events and longer intervals between events. We present a conceptual framework, based on past investigations and ecological theory, for predicting the consequences of this underappreciated aspect of climate change. We consider a broad range of terrestrial ecosystems that vary in their overall water balance. More extreme rainfall regimes are expected to increase the duration and severity of soil water stress in mesic ecosystems as intervals between rainfall events increase. In contrast, xeric ecosystems may exhibit the opposite response to extreme events. Larger but less frequent rainfall events may result in proportional reductions in evaporative losses in xeric systems, and thus may lead to greater soil water availability. Hydric (wetland) ecosystems are predicted to experience reduced periods of anoxia in response to prolonged intervals between rainfall events. Understanding these contingent effects of ecosystem water balance is necessary for predicting how more extreme precipitation regimes will modify ecosystem processes and alter interactions with related global change drivers.

}, keywords = {LTER-KNZ, Climate change, Drought, Ecosystems, Precipitation, soil water}, doi = {10.1641/B580908}, url = {https://academic.oup.com/bioscience/article/58/9/811/250853}, author = {Alan K. Knapp and Beier, C. and Briske, D.D. and Classen, A.T. and Luo, Y. and Reichstein, M. and M.D. Smith and Smith, S.D. and Bell, J.E. and Fay, P.A. and Heisler, J.L. and Leavitt, S.W and Sherry, R. and Smith, B. and Weng, E.} } @article {KNZ001202, title = {Conversion of grassland to coniferous woodland has limited effects on soil nitrogen cycle processes}, journal = {Soil Biology \& Biochemistry}, volume = {40}, year = {2008}, pages = {2627 -2633}, abstract = {

In the last century, conversion of native North American grasslands to Juniperus virginiana forests or woodlands has dramatically altered ecosystem structure and significantly increased ecosystem carbon (C) stocks. We compared soils under recently established J. virginiana forests and adjacent native C4-dominated grassland to assess changes in potential soil nitrogen (N) transformations and plant available N. Over a 2-year period, concentrations of extractable inorganic N were measured in soils from forest and grassland sites. Potential gross N ammonification, nitrification, and consumption rates were determined using 15N isotope-dilution under laboratory conditions, controlling for soil temperature and moisture content. Potential nitrification rates (Vmax) and microbial biomass, as well as soil physical and chemical properties were also assessed. Extractable NH4+ concentrations were significantly greater in grassland soils across the study period (P \≤ 0.01), but analysis by date indicated that differences in extractable inorganic N occurred more frequently in fall and winter, when grasses were senescent but J. virginiana was still active. Laboratory-based rates of gross N mineralization (ammonification) and nitrification were greater in grassland soils (P \≤ 0.05), but only on one of four dates. Potential nitrification rates (Vmax) were an order of magnitude greater than gross nitrification rates in both ecosystems, suggesting that nitrification is highly constrained by NH4+ availability. Differences in plant uptake of N, C inputs, and soil microclimate as forests replace grasslands may influence plant available N in the field, as evidenced by seasonal differences in soil extractable NH4+, and total soil C and N accumulation. However, we found few differences in potential soil N transformations under laboratory conditions, suggesting that this grassland-to-forest conversion caused little change in mineralizable organic N pools or potential microbial activity.

}, keywords = {LTER-KNZ, Extractable N, Forest encroachment, grassland, Isotope dilution, Juniperus, Microbial biomass, Mineralization, nitrification, Nitrogen cycling, prairie}, doi = {10.1016/j.soilbio.2008.07.005}, url = {https://www.sciencedirect.com/science/article/abs/pii/S0038071708002320?via\%3Dihub}, author = {McKinley, D.C. and C. W. Rice and John M. Blair} } @article {KNZ001138, title = {Cowbird removals unexpectedly increase productivity of a brood parasite and the songbird host}, journal = {Ecological Applications}, volume = {18}, year = {2008}, pages = {537 -548}, abstract = {

Generalist brood parasites reduce productivity and population growth of avian hosts and have been implicated in population declines of several songbirds of conservation concern. To estimate the demographic effects of brood parasitism on Bell\&$\#$39;s Vireos (Vireo bellii), we removed Brown-headed Cowbirds (Molothrus ater) in a replicated switchback experimental design. Cowbird removals decreased parasitism frequency from 77\% and 85\% at unmanipulated plots to 58\% and 47\% at removal plots in 2004 and 2005, respectively. Vireo productivity per pair was higher at cowbird removal plots when years were pooled (mean = 2.6 \± 0.2 [SE] young per pair) compared to unmanipulated plots (1.2 \± 0.1). Nest desertion frequency was lower at cowbird removal plots (35\% of parasitized nests) compared to unmanipulated plots (69\%) because removal of host eggs was the proximate cue for nest desertion, and vireos experienced lower rates of egg loss at cowbird removal plots. Nest success was higher among unparasitized than parasitized nests, and parasitized nests at cowbird removal plots had a higher probability of success than parasitized nests at unmanipulated plots. Unexpectedly, cowbird productivity from vireo pairs was higher at cowbird removal plots (mean = 0.3 \± 0.06 young per pair) than at unmanipulated plots (0.1 \± 0.03) because fewer parasitized nests were deserted and the probability of nest success was higher. Our study provides the first evidence that increases in cowbird productivity may be an unintended consequence of cowbird control programs, especially during the initial years of trapping when parasitism may only be moderately reduced. Thus, understanding the demographic impacts of cowbird removals requires an informed understanding of the behavioral ecology of host\–parasite interactions.

}, keywords = {LTER-KNZ}, doi = {10.1890/07-0984.1}, url = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/07-0984.1}, author = {Kosciuch, K.L. and Sandercock, B.K.} } @article {KNZ001099, title = {Carbon isotope variation in modern soils of the tallgrass prairie:Analogues for the interpretation of isotopicrecords derived from paleosols}, journal = {Quaternary International}, volume = {162-163}, year = {2007}, pages = {3 -20}, abstract = {Use of stable carbon isotope data from paleosols to reconstruct past plant community structure (C3 vs. C4) has become commonplace. In an effort to improve our ability to make isotope-based reconstructions and to better appreciate the pitfalls, investigations were conducted on both modern soils and paleosols in the Kansas grasslands. Stable carbon isotope data were derived from soils and vegetation on the near-pristine, C4-dominated grassland of the Konza Tallgrass Prairie Long-Term Ecological Research (LTER) site in northeastern Kansas. In order to evaluate variation of δ13C within the landscape, two levels of sampling were employed: 2 m-deep upland cores extracted to assess variation with depth in the soil profile, and, to assess variability across the landscape, surface samples along two transects and from within a 660{\texttimes}690 m grid. For transect and grid points, both the upper 2 cm of sediment and the aboveground biomass were collected. Core samples taken at Konza reveal that soil organic carbon was depleted in 13C within the upper 10{\textendash}20 cm relative to the remainder of the soil solum below, a phenomenon previously reported. In transects and the sample grid, soil organic carbon from soil surfaces was consistently more depleted in 13C than aboveground tissue of associated vegetation samples. Slope, azimuth, and insolation were computed from field data and a high-resolution DEM of the sample grid, but these variables offered no significant explanation of the spatial variability in δ13C data from soil organic carbon. The observation that modern landscape position has little effect on δ13C over short distances, at least in a C4-dominated community, lends support to the application of δ13C analysis to buried soils for paleoenvironmental reconstruction where paleolandscape position is often unknown. Stable carbon isotope data were derived from paleosols at from the Beisel-Steinle site located to the west of Konza in central Kansas. Three soils were examined: the interstadial paleosol within the Gilman Canyon Formation (c. 38{\textendash}27k cal yr BP), the Late Pleistocene{\textendash}Holocene Brady Soil, and the modern surface soil. With the exception of isotopic depletion at the top of the surface soil, all three soils exhibited similar δ13C values of about14{\textperthousand}, the same value realized in the soil cores from Konza, suggesting close similarity among the plant communities of the interstade, the Late Pleistocene{\textendash}Early Holocene transition, and pristine prairie of today. This investigation emphasizes the need for additional research into the variation in stable carbon isotope signals vertically within the profile and across the landscape. Issues include the source of the near-surface depletion zone, the relationship between isotopic values in the soil versus those of the vegetation, and variation in soil δ13C values δ13C throughout the landscape.}, keywords = {LTER-KNZ}, doi = {10.1016/j.quaint.2006.10.036}, author = {Johnson, W.C. and Willey, K.L. and G. L. Macpherson} } @article {KNZ001090, title = {Compensatory dynamics are rare in naturalecological communities}, journal = {Proceedings of the National Academy of Sciences}, volume = {104}, year = {2007}, pages = {3273 -3277}, abstract = {In population ecology, there has been a fundamental controversy about the relative importance of competition-driven (density-dependent) population regulation vs. abiotic influences such as temperature and precipitation. The same issue arises at the community level; are population sizes driven primarily by changes in the abundances of cooccurring competitors (i.e., compensatory dynamics), or do most species have a common response to environmental factors? Competitive interactions have had a central place in ecological theory, dating back to Gleason, Volterra, Hutchison and MacArthur, and, more recently, Hubbell{\textquoteright}s influential unified neutral theory of biodiversity and biogeography. If competitive interactions are important in driving year-to-year fluctuations in abundance, then changes in the abundance of one species should generally be accompanied by compensatory changes in the abundances of others. Thus, one necessary consequence of strong compensatory forces is that, on average, species within communities will covary negatively. Here we use measures of community covariance to assess the prevalence of negative covariance in 41 natural communities comprising different taxa at a range of spatial scales. We found that species in natural communities tended to covary positively rather than negatively, the opposite of what would be expected if compensatory dynamics were important. These findings suggest that abiotic factors such as temperature and precipitation are more important than competitive interactions in driving year-to-year fluctuations in species abundance within communities.}, keywords = {LTER-KNZ, biological interactions, Community dynamics, negative covariance, neutral models, zero-sum}, doi = {10.1073/pnas.0603798104}, author = {Houlahan, J.E. and Currie, D.J. and Cottenie, K. and Cumming, G.S. and Ernest, S.K.M. and Findlay, C.S. and Fuhlendorf, S.D. and Gaedke, U. and Legendre, P. and Magnuson, J.J. and McArdle, B.H. and Muldavin, E.H. and Noble, D. and Russell, R. and Stevens, R.D. and Willis, T.J. and Woiwod, I.P. and Wondzell, S.M.} } @phdthesis {KNZ001087, title = {Consequences of conversion of native Mesic grassland to coniferous forest on soil processes and ecosystem C and N storage}, volume = {PhD Dissertation}, year = {2007}, pages = {1 -200}, school = {Kansas State University}, type = {Ph.D. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ}, url = {http://krex.k-state.edu/dspace/handle/2097/253}, author = {McKinley, D.C.} } @article {KNZ001097, title = {Consumptionof mycorrhizal and saprophytic fungi by Collembola in grassland soils}, journal = {Soil Biology and Biochemistry}, volume = {39}, year = {2007}, pages = {2594 -2602}, abstract = {Although soil-dwelling Collembola can influence plant growth and nutrient cycling, their specific role in soil food webs is poorly understood. Soil-free microcosm studies suggest that Collembola are primarily fungivores where they feed preferentially on saprophytic fungi (SF) over other fungal types. We directly assessed collembolan consumption of arbuscular mycorrhizal fungi (AMF) and SF using plant{\textendash}soil mesocosms and natural abundance stable carbon isotope techniques. Mycorrhizal Andropogon gerardii (C4 grass) seedlings were placed in pots containing Collembola and soil from a C3 plant dominated site, while mycorrhizal Pascopyrum smithii (C3 grass) seedlings were placed in pots with Collembola and soil collected at a C4 plant dominated site. After 6 weeks, collembolans assimilated carbon derived from C3 and C4 sources in both A. gerardii and P. smithii treatments. Comparing Collembola isotope values in AMF vs. AMF-suppressed treatments, our data show that both AMF and SF were consumed in these experimental soil environments.}, keywords = {LTER-KNZ, Andropogon gerardii, Arbuscular mycorrhizal fungi, Collembola, grassland, Natural abundance stable isotopes, Pascopyrum smithii, Saprophytic fungi, δ13C}, doi = {10.1016/j.soilbio.2007.05.004}, author = {Jonas, J.L. and G.T. Wilson and White, P.M. and Anthony Joern} } @phdthesis {KNZ001073, title = {Canopy chlorophyll estimation with hyperspectral remote sensing}, volume = {PhD Dissertation}, year = {2006}, pages = {1 -192}, school = {Kansas State University}, type = {Ph.D. Thesis}, address = {Manhattan, KS}, abstract = {

In this research, proximal measurements of hyperspectral reflectance were used to develop models for estimating chlorophyll content in tallgrass prairie at leaf and canopy scales. Models were generated at the leaf scale and then extended to the canopy scale. Three chlorphyll estimation models were developed, one based on reflectance spectra and two derived from derivative transformations of the reflectance spectra. The triangle chlorophyll index (TCI) model was derived from the reflectance spectrum, whereas the first and second derivative indices (FDI and SDI) models were developed from the derivative transformed spectra. The three models were found to be well- correlated with the chlorophyll content measured with solvent extraction. The result indicated that the three models were effective for the leaf scale estimates of chlorophyll content. The three chlorophyll models developed at the leaf scale were further extended to the canopy scale and fine-scale images. The three models were found to be conditionally effective for estimating canopy chlorophyll content. The TCI model was more effective in dense vegetation, and the FDI and SDI models were better in sparser vegetation. This research suggests that the extension of chlorophyll models from the leaf scale to canopy scale is complex and affected not only by soil background, but also by canopy structure and components

}, keywords = {LTER-KNZ, canopy, chlorophyll content, hyperspectrum, remote sensing}, url = { http://hdl.handle.net/2097/252}, author = {Gao, J.} } @article {KNZ001063, title = {Climate change effects on plant disease: from genes to ecosystems}, journal = {Annual Review of Phytopathology}, volume = {44}, year = {2006}, pages = {489 -509}, abstract = {Research in the effects of climate change on plant disease continues to be limited, but some striking progress has been made. At the genomic level, advances in technologies for the high-throughput analysis of gene expression have made it possible to begin discriminating responses to different biotic and abiotic stressors and potential trade-offs in responses. At the scale of the individual plant, enough experiments have been performed to begin synthesizing the effects of climate variables on infection rates, though pathosystem-specific characteristics make synthesis challenging. Models of plant disease have now been developed to incorporate more sophisticated climate predictions. At the population level, the adaptive potential of plant and pathogen populations may prove to be one of the most important predictors of the magnitude of climate change effects. Ecosystem ecologists are now addressing the role of plant disease in ecosystem processes and the challenge of scaling up from individual infection probabilities to epidemics and broader impacts.}, keywords = {LTER-KNZ}, doi = {10.1146/annurev.phyto.44.070505.143420}, author = {Garrett, K.A. and Dendy, S.P. and Frank, E.E. and Rouse, M.N. and Travers, S.E.} } @mastersthesis {KNZ001080, title = {The coevolution of society and invasivespecies: Sericea lespedeza in the Kansas Flint Hills}, volume = {MA Thesis}, year = {2006}, school = {Kansas State University}, type = {M.S. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ}, author = {Cline, D.} } @mastersthesis {KNZ001126, title = {A comparison of the reproductive systems of the invasive Lespedeza cuneata (Dum.-Cours.) G. Don (Fabaceae) with three native congeners in the Flint Hills region of the tallgrass prairie}, volume = {MS Thesis}, year = {2006}, pages = {1 -95}, school = {Kansas State University}, type = {M.S. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ}, author = {Woods, T.M.} } @article {KNZ001016, title = {A comparison of the species-timerelationship across ecosystems and taxonomic groups}, journal = {Oikos}, volume = {112}, year = {2006}, pages = {185 -195}, abstract = {The species{\textendash}time relationship (STR) describes how the species richness of a community increases with the time span over which the community is observed. This pattern has numerous implications for both theory and conservation in much the same way as the species{\textendash}area relationship (SAR). However, the STR has received much less attention and to date only a handful of papers have been published on the pattern. Here we gather together 984 community time-series, representing 15 study areas and nine taxonomic groups, and evaluate their STRs in order to assess the generality of the STR, its consistency across ecosystems and taxonomic groups, its functional form, and its relationship to local species richness. In general, STRs were surprisingly similar across major taxonomic groups and ecosystem types. STRs tended to be well fit by both power and logarithmic functions, and power function exponents typically ranged between 0.2 and 0.4. Communities with high richness tended to have lower STR exponents, suggesting that factors increasing richness may simultaneously decrease turnover in ecological systems. Our results suggest that the STR is as fundamental an ecological pattern as the SAR, and raise questions about the general processes underlying this pattern. They also highlight the dynamic nature of most species assemblages, and the need to incorporate time scale in both basic and applied research on species richness patterns.}, keywords = {LTER-KNZ}, doi = {10.1111/j.0030-1299.2006.14223.x}, author = {White, E.P. and P. Adler and Lauenroth, W.K. and Gill, R.A. and Greenberg, D. and Kaufman, D.M. and Rassweiler, A. and Rusak, J.A. and M. A. Smith and Steinbeck, J. and Waide, R.B. and Yao, J.} } @phdthesis {KNZ001142, title = {Controls of nitrogen spiraling in Kansas streams}, volume = {PhD Dissertation}, year = {2006}, pages = {1 -157}, school = {Kansas State University}, type = {Ph.D. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ}, url = {http://krex.k-state.edu/dspace/handle/2097/174}, author = {O{\textquoteright}Brien, J.M.} } @article {KNZ001058, title = {Controls on nutrients across a prairie stream watershed: Land use and riparian cover effects}, journal = {Environmental Management}, volume = {37}, year = {2006}, pages = {636 -646}, abstract = {Nutrient inputs generally are increased by human-induced land use changes and can lead to eutrophication and impairment of surface waters. Understanding the scale at which land use influences nutrient loading is necessary for the development of management practices and policies that improve water quality. The authors assessed the relationships between land use and stream nutrients in a prairie watershed dominated by intermittent stream flow in the first-order higher elevation reaches. Total nitrogen, nitrate, and phosphorus concentrations were greater in tributaries occupying the lower portions of the watershed, closely mirroring the increased density of row crop agriculture from headwaters to lower-elevation alluvial areas. Land cover classified at three spatial scales in each sub-basin above sampling sites (riparian in the entire catchment, catchment land cover, and riparian across the 2 km upstream) was highly correlated with variation in both total nitrogen (r2 = 53\%, 52\%, and 49\%, respectively) and nitrate (r2 = 69\%, 65\%, and 56\%, respectively) concentrations among sites. However, phosphorus concentrations were not significantly associated with riparian or catchment land cover classes at any spatial scale. Separating land use from riparian cover in the entire watershed was difficult, but riparian cover was most closely correlated with in-stream nutrient concentrations. By controlling for land cover, a significant correlation of riparian cover for the 2 km above the sampling site with in-stream nutrient concentrations could be established. Surprisingly, land use in the entire watershed, including small intermittent streams, had a large influence on average downstream water quality although the headwater streams were not flowing for a substantial portion of the year. This suggests that nutrient criteria may not be met only by managing permanently flowing streams.}, keywords = {LTER-KNZ, nitrogen, Phosphorus, Prairie watershed, Riparian, water quality}, doi = {10.1007/s00267-004-0072-3}, author = {W. K. Dodds and Oakes, R.M.} } @article {KNZ001082, title = {Convergence and contingency in production-precipitation relationships in North American and South African C4 grasslands}, journal = {Oecologia}, volume = {149}, year = {2006}, pages = {456 -464}, abstract = {Mesic grasslands in North America and South Africa share many structural attributes, but less is known of their functional similarities. We assessed the control of a key ecosystem process, aboveground net primary production (ANPP), by interannual variation in precipitation amount and pattern via analysis of data sets (15- and 24-year periods) from long-term research programs on each continent. Both sites were dominated by C4 grasses and had similar growing season climates; thus, we expected convergence in precipitation{\textendash}ANPP relationships. Lack of convergence, however, would support an alternative hypothesis{\textemdash}that differences in evolutionary history and purportedly greater climatic variability in South Africa fundamentally alter the functioning of southern versus northern hemisphere grasslands. Neither mean annual precipitation nor mean ANPP differed between the South African and North American sites (838 vs. 857 mm/year, 423.5 vs. 461.4 g/m2 respectively) and growing season precipitation{\textendash}ANPP relationships were similar. Despite overall convergence, there were differences between sites in how the seasonal timing of precipitation affected ANPP. In particular, interannual variability in precipitation that fell during the first half of the growing season strongly affected annual ANPP in South Africa (P < 0.01), but was not related to ANPP in North America (P = 0.098). Both sites were affected similarly by late season precipitation. Divergence in the seasonal course of available soil moisture (chronically low in the winter and early spring in the South African site vs. high in the North American site) is proposed as a key contingent factor explaining differential sensitivity in ANPP to early season precipitation in these two grasslands. These long-term data sets provided no support for greater rainfall, temperature or ANPP variability in the South African versus the North American site. However, greater sensitivity of ANPP to early season precipitation in the South African grassland suggests that future patterns of productivity may be more responsive to seasonal changes in climate compared with the North American site.}, keywords = {LTER-KNZ, climate, Evolutionary history, Net primary production, Precipitation, soil moisture}, doi = {10.1007/s00442-006-0468-2}, author = {Alan K. Knapp and Burns, C.E. and Fynn, R.W.S. and Kirkman, K.P. and Morris, C.D. and M.D. Smith} } @article {KNZ001049, title = {Can rDNA analyses of diverse fungal communities in soil and rootsdetect effects of environmental manipulations--a case study from tallgrass prairie}, journal = {Mycologia}, volume = {97}, year = {2005}, pages = {1177 -1194}, abstract = {

We tested whether fungal communities are impacted by nitrogen deposition or increased precipitation by PCR-amplifying partial fungal rRNA genes from 24 soil and 24 root samples from a nitrogen enrichment and irrigation experiment in a tallgrass prairie at Konza Prairie Biological Station in northeastern Kansas, U.S.A. Obtained fungal sequences represented great fungal diversity that was distributed mainly in ascomycetes and basiodiomycetes; only a few zygomycetes and glomeromycetes were detected. Conservative extrapolated estimates of the fungal species richness suggest that the true richness may be at least twice as high as observed. The effects of nitrogen enrichment or irrigation on fungal community composition, diversity or clone richness could not be unambiguously assessed because of the overwhelming diversity. However, soil communities differed from root communities in diversity, richness and composition. The compositional differences were largely attributable to an abundant, soil-inhabiting group placed as a well-supported sister group to other ascomycetes. This group likely represents a novel group of fungi. We conclude that the great fungal richness in this ecosystem precluded a reliable assessment of anthropogenic impacts on soil or rhizosphere communities using the applied sampling scheme, and that detection of novel fungi in soil may be more a rule than an exception.

}, keywords = {LTER-KNZ, Biodiversity, environmental change, fungi, nitrogen, Precipitation, soil DNA}, doi = {10.3852/mycologia.97.6.1177}, author = {A. Jumpponen and Johnson, L.C.} } @article {KNZ001147, title = {Carrion beetles (Coleoptera: Silphidae) of the Konza Prairie Biological Stationbeetles (Coleoptera: Silphidae) of the Konza Prairie Biological Station}, journal = {Journal of the Kansas Entomological Society}, volume = {78}, year = {2005}, pages = {124 -123}, abstract = {Pitfall traps were used to determine diversity, seasonality, and numbers of burying beetles on the Konza Prairie Biological Station (KPBS) during the summers of 1997 and 1998. Traps were baited with either beef liver (1997) or whole mouse carcasses (1997 and 1998); significantly more carrion beetles were found in traps baited with carcasses. A total of 1003 carrion beetles, representing 8 species, were trapped over the course of 1556 trap nights. One of these species, Necrophila americana Linneaus, had not previously been recorded in Riley County. One additional species was found at sites where pitfall trap bait was discarded, bringing the total number of KPBS silphid species to 9. Bait age was an important determinant in attracting silphids to pitfall traps, as numbers of beetles in the trap continued to increase with bait age up to 6 days. Grassland topography (upland vs. lowland trap sites) significantly affected the numbers of carrion beetles trapped. Grassland burn history did not affect number of carrion beetles trapped, but did seem to influence species diversity.}, keywords = {LTER-KNZ, Konza Prairie Biological Station, Nicrophorus marginatus, pitfall trap, seasonal occurrence, Silphidae}, doi = {10.2317/0305.06.1}, author = {Rintoul, D.A. and Krueger, L.M. and Woodard, C. and Throne, J.E.} } @article {KNZ00895, title = {Chronic nitrogen loading in streams}, journal = {Ecosystems}, volume = {8}, year = {2005}, pages = {442 -453}, keywords = {LTER-KNZ}, doi = {10.1007/s10021-003-0143-6}, author = {Bernot, M.J. and W. K. Dodds} } @proceedings {KNZ00979, title = {Comparing the influence of precipitation, fire, and topography on plant productivity in the tallgrass prairie}, volume = {3}, year = {2005}, keywords = {LTER-KNZ}, url = {http://tiee.ecoed.net/vol/v3/issues/data_sets/konza/abstract.html}, author = {Jesse B. Nippert and John M. Blair} } @article {KNZ00963, title = {Competition, facilitation, and niche differentiation in two foliar pathogens}, journal = {Oecologia}, volume = {143}, year = {2005}, pages = {449 -457}, abstract = {We studied competition between the obligate biotroph Puccinia triticina (designated here as Puccinia) and the facultative saprophyte Pyrenophora tritici-repentis (designated here as Pyrenophora) in older and younger leaves in a set of three host genotypes selected to be resistant to Puccinia only, Pyrenophora only, or neither. Age-related resistance is important for both of these pathogens. The facultative saprophyte Pyrenophora was generally a stronger competitor than the biotrophic Puccinia, even experiencing facilitation from the presence of Puccinia when Pyrenophora had the advantage of earlier inoculation. Both pathogen species produced the most spores when they were introduced before the competing species and more spores when introduced simultaneously compared to after the competitor. The pre-interactive niche of Puccinia was larger than the post-interactive niche and sporulation by Puccinia was substantially reduced in environments in which Pyrenophora had high sporulation rates. The pre-interactive niche of Pyrenophora was similar to the post-interactive niche and Pyrenophora had proportionally lower reductions in sporulation due to interspecific competition in the pre-interactive niche.}, keywords = {LTER-KNZ, Facultative saprophytes, Impact niche, Obligate parasites, Requirement niche, Rust fungi}, doi = {10.1007/s00442-004-1814-x}, author = {Al-Naimi, F. and Garrett, K.A. and Bockus, W.W.} } @proceedings {KNZ001029, title = {Contribution to the taxonomy and faunistics of the genus Meropleon Dyar (Lepidoptera: Noctuidae)}, year = {2005}, pages = {812 -819}, abstract = {A new species of owlet moth, Meropleon linae (Lepidoptera: Noctuidae) from Kansas, is described and illustrated. Meropleon linae is distinguished from other species of Meropleon by forewing color and pattern, shape of thevalva, and structure of the aedoeagus. Meropleon linae is most similar morphologically to M. cinnamicolor Ferguson. New distribution records for M. ambifuscum (Newman) and the first record for M. titan Todd in Kansas are given.}, keywords = {LTER-KNZ}, url = {http://cat.inist.fr/?aModele=afficheN\&cpsidt=17159757}, author = {Metlevski, J.} } @article {KNZ001067, title = {Carbon and nitrogen pools in a tallgrass prairie soil under elevated carbon dioxide}, journal = {Soil Science Society of America Journal}, volume = {68}, year = {2004}, pages = {148 -153}, abstract = {

Soil is a potential C sink and could offset rising atmospheric CO2 The capacity of soils to store and sequester C will depend on the rate of C inputs from plant productivity relative to C exports controlled by microbial decomposition. Our objective was to measure pools of soil C and N to assess the potential for C accrual and changes to N stocks as influenced by elevated atmospheric CO2 Treatments (three replications, randomized complete block design) were ambient CO2\—no chamber (NC), ambient CO2\—chamber (AC), and two times ambient CO2\—chamber (EC). Long-term (290 d) incubations (35\°C) were conducted to assess changes in the slow soil fractions of potentially mineralizable C (PMC) and potentially mineralizable N (PMN). Potentially mineralizable C was enhanced (P \< 0.1) by 19 and 24\% in EC relative to AC and NC soil at the 0- to 5- and 5- to 15-cm depths, respectively. Potentially mineralizable N was significantly greater by 14\% at the 0- to 5-cm depth in EC relative to AC, but decreased by 12\% in EC relative to NC (P \< 0.1). Measurements of PMC indicate that increases in total soil C under elevated CO2 in a previous study were a consequence of accrual into the slow pool. Relatively large amounts of new C deposited as a result of elevated CO2 (Cnew) remained in the soil after the 290-d incubation. In contrast to accumulation of C into the slow fraction, Cnew was integrated into a passive fraction of soil organic matter (SOM). Accumulation of N was also detected in the whole soil, which cannot be explained by current estimates of ecosystem N flux.

}, keywords = {LTER-KNZ}, doi = {10.2136/sssaj2004.1480}, author = {Williams, M.A. and C. W. Rice and Omay, A. and Owensby, C.} } @article {KNZ00925, title = {Carbon and nitrogen stoichiometry and nitrogen cycling rates in streams}, journal = {Oecologia}, volume = {140}, year = {2004}, pages = {458 -467}, abstract = {Stoichiometric analyses can be used to investigate the linkages between N and C cycles and how these linkages influence biogeochemistry at many scales, from components of individual ecosystems up to the biosphere. N-specific NH4 + uptake rates were measured in eight streams using short-term 15N tracer additions, and C to N ratios (C:N) were determined from living and non-living organic matter collected from ten streams. These data were also compared to previously published data compiled from studies of lakes, ponds, wetlands, forests, and tundra. There was a significant negative relationship between C:N and N-specific uptake rate; C:N could account for 41\% of the variance in N-specific uptake rate across all streams, and the relationship held in five of eight streams. Most of the variation in N-specific uptake rate was contributed by detrital and primary producer compartments with large values of C:N and small values for N-specific uptake rate. In streams, particulate materials are not as likely to move downstream as dissolved N, so if N is cycling in a particulate compartment, N retention is likely to be greater. Together, these data suggest that N retention may depend in part on C:N of living and non-living organic matter in streams. Factors that alter C:N of stream ecosystem compartments, such as removal of riparian vegetation or N fertilization, may influence the amount of retention attributed to these ecosystem compartments by causing shifts in stoichiometry. Our analysis suggests that C:N of ecosystem compartments can be used to link N-cycling models across streams.}, keywords = {LTER-KNZ, carbon, Carbon:Nitrogen ratio, nitrogen, stoichiometry, streams}, doi = {10.1007/s00442-004-1599-y}, author = {W. K. Dodds and Marti, E. and Tank, J. and Pontius, J.L. and Hamilton, S.K. and Grimm, N.B. and W.B. Bowden and W.H. McDowell and Peterson, B.J. and Valett, H.M. and Webster, J.R. and Gregory, S.} } @article {KNZ001151, title = {Comparison of hyperspectral and multispectral data for estimating leaf area index in four biomes}, journal = {Remote Sensing of Environment}, volume = {91}, year = {2004}, pages = {508 -520}, abstract = {Motivated by the increasing importance of hyperspectral remote sensing data, this study sought to determine whether current-generation narrow-band hyperspectral remote sensing data could better track vegetation leaf area index (LAI) than traditional broad-band multispectral data. The study takes advantage of a unique dataset, wherein field measurements of LAI were acquired at the same general time and grain size as both Landsat ETM+ and AVIRIS (Airborne Visible/Infrared Imaging Spectrometer) imagery in four different biomes. Biome types sampled included row-crop agriculture, tallgrass prairie, mixed hardwood-conifer forest, and boreal conifer forest. The effects of bandwidth, band placement, and number of bands were isolated from radiometric quality by comparing regression models derived from individual AVIRIS channels with those derived from simulated ETM+ and MODIS channels using the AVIRIS data. Models with selected subsets of individual AVIRIS channels performed better to predict LAI than those based on the broadband datasets, although the potential to overfit models using the large number of available AVIRIS bands is a concern. Models based on actual ETM+ data were generally stronger than those based on simulated ETM+ data, suggesting that, for predicting LAI, ETM+ data suffer no penalty for having lower radiometric quality. NDVI was generally not sensitive to LAI at the four sites. Band placement of broad-band sensors (e.g., simulated ETM+ and MODIS) did not affect relationships with LAI, suggesting that there is no inherent advantage to MODIS spectral properties over those of ETM+ for estimating LAI. Spectral channels in the red-edge and shortwave-infrared regions were generally more important than those in the near-infrared for predicting LAI.}, keywords = {LTER-KNZ, Hyperspectral, LAI, Multispectral}, doi = {10.1016/j.rse.2004.04.010}, author = {Lee, K-S. and Cohen, W.B. and Kennedy, R.E. and Maiersperger, T.K. and Gower, S.T.} } @article {KNZ00894, title = {Competition and coexistence in grassland co-dominants: responses to neighbor removal and resource availability}, journal = {Canadian Journal of Botany}, volume = {82}, year = {2004}, pages = {450 -460}, abstract = {We examined the role of interspecific competition in the regulation of abundance and coexistence of the dominant grasses in tallgrass prairie using a removal experiment with Andropogon gerardii Vitman and Sorghastrum nutans L. Nash, two of the most abundant grasses in tallgrass prairie. Plant removal treatments (using foliar herbicide), applied to 0.3-m2 plots at the Konza Prairie Biological Station (northeast Kansas, USA), included removal of all A. gerardii, removal of all S. nutans, and no removal. To determine whether soil fertility altered the outcome, we included a fertilizer addition treatment (10 g N{\textperiodcentered}m–2) fully crossed with the removal treatments. Andropogon gerardii removal resulted in significantly increased net photosynthesis, stomatal conductance, and tiller mass in S. nutans. Sorghastrum nutans removal had little effect on A. gerardii, suggesting asymmetric competition. Fertilizer significantly increased tiller mass and flowering stalk production in S. nutans, but had little effect on A. gerardii. The ability of A. gerardii to suppress the performance of S. nutans is consistent with the greater abundance of A. gerardii over much of the tallgrass prairie, while the ability of S. nutans to take advantage of increased resources may be one mechanism by which it avoids competitive exclusion. Because of the greater variability in the performance of S. nutans than in that of A. gerardii, any natural or anthropogenic alterations to this grassland that lead to shifts in dominance between these species may affect ecosystem productivity and stability.Key words: Andropogon gerardii, competition, grassland, neighbour removal, photosynthesis, Sorghastrum nutans, tallgrass prairie.}, keywords = {LTER-KNZ}, doi = {10.1139/b04-016}, author = {Silletti, A.M. and Alan K. Knapp and John M. Blair} } @article {KNZ00919, title = {Competitive relationships of Andropogon gerardii (big bluestem) from remnant and restored native populations and select cultivated varieties}, journal = {Functional Ecology}, volume = {18}, year = {2004}, pages = {451 -457}, abstract = {1Although genetic differentiation among plant populations is well known, its relevance for preserving the integrity of native ecosystems has received little attention. In a series of competition experiments with Andropogon gerardii Vitman, a dominant species of the North American Tallgrass Prairie, plant performance was related to seed provenance and restoration activities. 2Glasshouse experiments showed plant performance to be a function of seed source. Differential target plant performance relative to competitor identity was observed when plant performance was assessed across a range of competitor densities. Local and non-local plants were larger when competing against non-local plants relative to the local and cultivar plants, while cultivar plants were consistently larger than local and non-local plants regardless of competitor identity or density. The consistency of cultivar performance could reflect directional selection during cultivar development for consistently high fecundity, vigorous vegetative growth and resistance to pathogens. 3In a field experiment, non-local plants were half the size of local and cultivar plants, supporting recognition of seed provenances of A. gerardii based on differences in plant performance among source populations observed in the glasshouse study, and previous genetic analyses of the same populations. 4This study establishes that seed provenance and restoration activities influence the competitive ability of a dominant species which, in turn, may affect plant community structure and potential ecosystem function.}, keywords = {LTER-KNZ}, doi = {10.1111/j.0269-8463.2004.00850.x}, author = {Gustafson, D.J. and D.J. Gibson and Nickrent, D.L.} } @article {KNZ00918, title = {Conservation genetics of two co-dominant species in the endangered tallgrass prairie ecosystem}, journal = {Journal of Applied Ecology}, volume = {41}, year = {2004}, pages = {389 -397}, abstract = {

1. Global habitat fragmentation and loss of undisturbed grasslands has led to the use of non-local seed and cultivars in restoration. There is concern that these sources may be genetically depauperate and their introduction may lead to loss of unique local genotypes. Within this context we considered the issue with regard to the once widespread but now highly fragmented North American tallgrass prairie. 2. We characterized the genetic diversity and genetic relationships of the co-dominant species in this system, big bluestem Andropogon gerardii and Indian grass Sorghastrum nutans, from seven remnant and six restored local tallgrass prairies, a non-local remnant prairie, and five cultivated varieties. 3. Randomly amplified polymorphic DNA (RAPD) analysis of these grasses showed that genetic diversity was mostly retained within rather than among populations, and did not differ among restored or remnant populations or cultivars. 4. Genetic diversity estimates were not correlated with the area of the grassland, nor was there a clear association between diversity and species abundance. All of the restored grasslands in this study were established with seed from at least two local populations and were as genetically diverse as remnant sites. 5. Principal components analysis of RAPD band frequencies showed that the local remnant and restored populations were genetically different from the non-local remnant grasslands and were consistently different to the cultivars. The genetic relationships among local remnant and restored populations reflected biogeography and human activities. 6. Synthesis and applications. Restoration practitioners have often assumed that small populations are genetically depauperate and therefore the need for multiple seed sources to increase genetic diversity outweighs concerns over potential genetic differences among widespread species. Our research, however, indicates that genetic diversity is much less of an issue in these perennial outcrossing autopolyploid grasses than genetic differences among local and non-local or cultivar seed sources. Combining these results with our previous research, indicating differences in plant performance as a function of the source population, suggests that genetic differences and ecological performance among local and non-local seed sources are more of a concern than genetic diversity. Translocating non-local seed in order to increase diversity, or using cultivars, is likely to alter the genetic structure of remnant populations and potentially influence the associated community and affect ecosystem structure and function in unforeseen ways.

}, keywords = {LTER-KNZ}, doi = {10.1111/j.0021-8901.2004.00904.x}, author = {Gustafson, D.J. and D.J. Gibson and Nickrent, D.L.} } @article {KNZ00899, title = {On the construction and calibration of dual probe heat capacity sensors}, journal = {Soil Science Society of America Journal}, volume = {68}, year = {2004}, pages = {1185 -1190}, abstract = {Dual-probe heat-capacity (DPHC) sensors can be used to measure soil heat capacity (C), water content, and temperature. Research was conducted to test design factors that affect sensor calibration, including: (i) calibration media, (ii) diameter and length of the needle probes, (iii) sensor body material, and (vi) duration and total power of the applied heat pulse. All sensors were calibrated in media with known C, including: agar (water), water-saturated glass beads, and dry glass beads. Calibration consisted of collecting heat pulse data in a given media and then calculating the apparent probe spacing (r app, distance between heater and detector needles) that yielded correct value of C An ideal sensor would have the same r app regardless of media type. The r app for all sensor designs increased as C decreased, on average changing by 6.7\% between agar and dry beads. This undesirable result was consistent with previous studies that showed DPHC sensors calibrated in agar overestimated C in drier soils. Needle diameter (1.27 vs. 1.65 mm), sensor body material (urethane vs. high-conductivity epoxy), and shortening of the detector probe had a small effect on r app Sensors made with urethane bodies, 1.27-mm diam. needle probes, and shortened temperature probes showed less sensitivity to calibration media and are therefore recommended. The r app for this design only increased by 2.6\% between dry and water-saturated wet beads. Apparent probe spacing was not affected by changes in total applied power (400{\textendash}1600 J m-1) or heat pulse duration (2{\textendash}16 s) when the correct analytical model was used to compute C}, keywords = {LTER-KNZ}, doi = {10.2136/sssaj2004.1185}, author = {J.M. Ham and Benson, E.J.} } @article {KNZ00917, title = {Convergence across biomes to a common rain-use efficiency}, journal = {Nature}, volume = {429}, year = {2004}, pages = {651 -654}, keywords = {LTER-KNZ}, doi = {10.1038/nature02561}, author = {Huxman, T.E. and M.D. Smith and Fay, P.A. and Alan K. Knapp and Shaw, M.R. and Loik, M.E. and Smith, S.D. and Tissue, D.T. and Zak, J.C. and Weltzin, J.F. and Pockman, W.T. and Sala, O.E. and Haddad, B.M. and Harte, J. and Koch, G.W. and Schwinning, S. and Small, E.E. and Williams, D.G.} } @phdthesis {KNZ00964, title = {Cytogenetic characterization and disease resistance of perennial grasses and disease response to host diversity}, volume = {PhD Dissertation}, year = {2004}, school = {Kansas State University}, type = {Ph.D. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ}, author = {Cox, C.M.} } @article {KNZ00867, title = {C3 shrub expansion in a C4 grassland: positive post-fire responses in resources and shoot growth}, journal = {American Journal of Botany}, volume = {90}, year = {2003}, pages = {1496 -1501}, abstract = {Changes in land management and reductions in fire frequency have enabled woody species to increase in grasslands worldwide. Nevertheless, fire is rarely eliminated from grasslands, and for shrubs to survive, they must be able cope with fire and replace aboveground structures. Because new shoots may have more available solar radiation, greater root : shoot ratios, and thus more resources available belowground after fire compared to undisturbed shrub communities, we hypothesized that carbon, nutrient, and water relations may be enhanced in stems compared to those in an undisturbed grassland. However, this same post-fire resource pulse stimulates the grasses and may intensify competitive interactions between shrubs and grasses. To test these predictions, we measured seasonal patterns in net photosynthesis (A), predawn xylem pressure potentials (XPP), leaf nitrogen (N) content, and productivity of Cornus drummondii shoots from shrub patches (islands) of different sizes in mesic grasslands burned annually, burned infrequently, and protected from fire. Seasonal average A was 20\% higher (P = 0.016) in burned than in unburned shrubs, regardless of island size. Shrubs in burned sites also produced shoots with higher leaf N than unburned shrubs, and N content was higher in leaves from small islands compared to large islands (P < 0.0001). Burning caused a decrease in late summer predawn XPP in small islands (-3.1 MPa), whereas burned large islands did not differ from unburned shrubs. Post-fire productivity of new shoots was significantly greater compared to shoots in unburned sites. These results indicate that a transient period of high resource availability after fire allows for increased growth and rapid recovery of grassland shrubs. Thus, although fire has a negative effect on aboveground biomass of shrubs, the post-fire increases in resource availability, which enhance growth in the dominant grasses, are also important for recovery of woody species.}, keywords = {LTER-KNZ, C3, C4, Cornus drummondii, fire, shrub, tallgrass prairie, transient maxima hypothesis, woody expansion}, doi = {10.3732/ajb.90.10.1496}, author = {McCarron, J.K. and Alan K. Knapp} } @book {KNZ00910, title = {Climate variability and ecosystem response at Long-Term Ecological Research sites}, year = {2003}, pages = {459 -}, publisher = {Oxford University Press}, organization = {Oxford University Press}, address = {New York}, keywords = {LTER-KNZ}, author = {Greenland, D. and Goodin, D.G. and Smith, R.C.} } @inbook {KNZ00907, title = {Climate variability in tallgrass prairie at multiple timescales: Konza Prairie Biological Station}, booktitle = {Climate Variability and Ecosystem Response at Long-Term Ecological Research Sites}, year = {2003}, pages = {411 -424}, publisher = {Oxford University Press}, organization = {Oxford University Press}, address = {New York}, keywords = {LTER-KNZ}, author = {Goodin, D.G. and P. Fay and McHugh, M.J.}, editor = {Greenland, D. and Goodin, D.G. and Smith, R.C.} } @article {KNZ00873, title = {A comparative assessment of potential mechanisms influencing plant species richness in grazed grasslands}, journal = {Oecologia}, volume = {137}, year = {2003}, pages = {385 -391}, abstract = {Grazing by large ungulates often increases plant species richness in grasslands of moderate to high productivity. In a mesic North American grassland with and without the presence of bison (Bos bison), a native ungulate grazer, three non-exclusive hypotheses for increased plant species richness in grazed grasslands were evaluated: (1) bison grazing enhances levels of resource (light and N) availability, enabling species that depend on higher resource availability to co-occur; (2) spatial heterogeneity in resource availability is enhanced by bison, enabling coexistence of a greater number of plant species; (3) increased species turnover (i.e. increased species colonization and establishment) in grazed grassland is associated with enhanced plant species richness. We measured availability and spatial heterogeneity in light, water and N, and calculated species turnover from long-term data in grazed and ungrazed sites in a North American tallgrass prairie. Both regression and path analyses were performed to evaluate the potential of the three hypothesized mechanisms to explain observed patterns of plant species richness under field conditions. Experimental grazing by bison increased plant species richness by 25\% over an 8-year period. Neither heterogeneity nor absolute levels of soil water or available N were related to patterns of species richness in grazed and ungrazed sites. However, high spatial heterogeneity in light and higher rates of species turnover were both strongly related to increases in plant species richness in grazed areas. This suggests that creation of a mosaic of patches with high and low biomass (the primary determinant of light availability in mesic grasslands) and promotion of a dynamic species pool are the most important mechanisms by which grazers affect species richness in high productivity grasslands.}, keywords = {LTER-KNZ, colonization, Grazing, heterogeneity, Species richness, tallgrass prairie}, doi = {10.1007/s00442-003-1360-y}, author = {Bakker, C. and John M. Blair and Alan K. Knapp} } @article {KNZ00923, title = {Comparing denitrification estimates for a Texas estuary by using acetylene inhibition and membrane inlet mass spectrometry}, journal = {Applied and Environmental Microbiology}, volume = {69}, year = {2003}, pages = {5950 -5956}, abstract = {Characterizing denitrification rates in aquatic ecosystems is essential to understanding how systems may respond to increased nutrient loading. Thus, it is important to ensure the precision and accuracy of the methods employed for measuring denitrification rates. The acetylene (C2H2) inhibition method is a simple technique for estimating denitrification. However, potential problems, such as inhibition of nitrification and incomplete inhibition of nitrous oxide reduction, may influence rate estimates. Recently, membrane inlet mass spectrometry (MIMS) has been used to measure denitrification in aquatic systems. Comparable results were obtained with MIMS and C2H2 inhibition methods when chloramphenicol was added to C2H2 inhibition assay mixtures to inhibit new synthesis of denitrifying enzymes. Dissolved-oxygen profiles indicated that surface layers of sediment cores subjected to the MIMS flowthrough incubation remained oxic whereas cores incubated using the C2H2 inhibition methods did not. Analysis of the microbial assemblages before and after incubations indicated significant changes in the sediment surface populations during the long flowthrough incubation for MIMS analysis but not during the shorter incubation used for the C2H2 inhibition method. However, bacterial community changes were also small in MIMS cores at the oxygen transition zone where denitrification occurs. The C2H2 inhibition method with chloramphenicol addition, conducted over short incubation intervals, provides a cost-effective method for estimating denitrification, and rate estimates are comparable to those obtained by the MIMS method.}, keywords = {LTER-KNZ}, doi = {10.1128/AEM.69.10.5950-5956.2003}, author = {Bernot, M.J. and W. K. Dodds and Gardner, W.S. and McCarthy, M.J. and Sobolev, D. and Tank, J.L.} } @article {KNZ001150, title = {Comparisons of land cover and LAI estimates derived from ETM+ and MODIS for four sites in North America: a quality assessment of 2000/2001 provisional MODIS products}, journal = {Remote Sensing of Environment}, volume = {88}, year = {2003}, pages = {221 -362}, abstract = {The MODIS land science team produces a number of standard products, including land cover and leaf area index (LAI). Critical to the success of MODIS and other sensor products is an independent evaluation of product quality. In that context, we describe a study using field data and Landsat ETM+ to map land cover and LAI at four 49-km2 sites in North America containing agricultural cropland (AGRO), prairie grassland (KONZ), boreal needleleaf forest, and temperate mixed forest. The purpose was to: (1) develop accurate maps of land cover, based on the MODIS IGBP (International Geosphere{\textendash}Biosphere Programme) land cover classification scheme; (2) derive continuous surfaces of LAI that capture the mean and variability of the LAI field measurements; and (3) conduct initial MODIS validation exercises to assess the quality of early (i.e., provisional) MODIS products. ETM+ land cover maps varied in overall accuracy from 81\% to 95\%. The boreal forest was the most spatially complex, had the greatest number of classes, and the lowest accuracy. The intensive agricultural cropland had the simplest spatial structure, the least number of classes, and the highest overall accuracy. At each site, mapped LAI patterns generally followed patterns of land cover across the site. Predicted versus observed LAI indicated a high degree of correspondence between field-based measures and ETM+ predictions of LAI. Direct comparisons of ETM+ land cover maps with Collection 3 MODIS cover maps revealed several important distinctions and similarities. One obvious difference was associated with image/map resolution. ETM+ captured much of the spatial complexity of land cover at the sites. In contrast, the relatively coarse resolution of MODIS did not allow for that level of spatial detail. Over the extent of all sites, the greatest difference was an overprediction by MODIS of evergreen needleleaf forest cover at the boreal forest site, which consisted largely of open shrubland, woody savanna, and savanna. At the agricultural, temperate mixed forest, and prairie grassland sites, ETM+ and MODIS cover estimates were similar. Collection 3 MODIS-based LAI estimates were considerably higher (up to 4 m2 m-2) than those based on ETM+ LAI at each site. There are numerous probable reasons for this, the most important being the algorithms{\textquoteright} sensitivity to MODIS reflectance calibration, its use of a prelaunch AVHRR-based land cover map, and its apparent reliance on mainly red and near-IR reflectance. Samples of Collection 4 LAI products were examined and found to consist of significantly improved LAI predictions for KONZ, and to some extent for AGRO, but not for the other two sites. In this study, we demonstrate that MODIS reflectance data are highly correlated with LAI across three study sites, with relationships increasing in strength from 500 to 1000 m spatial resolution, when shortwave-infrared bands are included.}, keywords = {LTER-KNZ, BigFoot, ETM, IGBP, Land cover, Leaf area index, MODIS, Validation}, doi = {10.1016/j.rse.2003.06.006}, author = {Cohen, W.B. and Maiersperger, T.K. and Yang, Z. and Gower, S.T. and Turner, D.P. and Ritts, W.D. and Berterretche, M. and Running, S.W.} } @article {KNZ00838, title = {Consequences of shrub expansion in mesic grassland: resource alterations and graminoid responses}, journal = {Journal of Vegetation Science}, volume = {14}, year = {2003}, pages = {487 -496}, abstract = {In the mesic grasslands of the central United States, the shrub Cornus drummondii has undergone widespread expansion in the absence of recurrent fire. We quantified alterations in light, water and N caused by C. drummondii expansion in tall-grass prairie and assessed the hypothesis that these alterations are consistent with models of resource enrichment by woody plants. Responses in graminoid species, particularly the dominant C4 grass Andropogon gerardii, were concurrently evaluated. We also removed established shrub islands to quantify their legacy effect on resource availability and assess the capability of this grassland to recover in sites formerly dominated by woody plants. The primary effect of shrub expansion on resource availability was an 87\% reduction in light available to the herbaceous understorey. This reduced C uptake and N use efficiency in A. gerardii and lowered graminoid cover and ANPP at the grass-shrub ecotone relative to undisturbed grassland. Shrub removal created a pulse in light and N availability, eliciting high C gain in A. gerardii in the first year after removal. By year two, light and N availability within shrub removal areas returned to levels typical of grassland, as had graminoid cover and ANPP were similar to those in open grassland. Recovery within central areas of shrub removal sites lagged behind that at the former grass-shrub ecotone. These results indicate that the apparent alternative stable state of C. drummondii dominance in tall-grass prairie is biotically maintained and driven by reductions in light, rather than resource enrichment. Within areas of shrub removal, the legacy effect of C. drummondii dominance is manifest primarily through the loss of rhizomes of the dominant grasses, rather than any long-term changes in resource availability. C. drummondii removal facilitates grassland recovery, but the effort required to initiate this transition is a significant cost of woody plant expansion in mesic grasslands. Prevention of woody plant expansion in remnant tall-grass prairies is, therefore, a preferred management option.}, keywords = {LTER-KNZ, Cornus drummondii, Grassland recovery, land cover change, Tall-grass prairie, Woody plant expansion}, doi = {10.1111/j.1654-1103.2003.tb02175.x}, author = {Lett, M.S. and Alan K. Knapp} } @article {KNZ00860, title = {A cross-biome comparison of daily light use efficiency for gross primary production}, journal = {Global Change Biology}, volume = {9}, year = {2003}, pages = {383 -395}, abstract = {Vegetation light use efficiency is a key physiological parameter at the canopy scale, and at the daily time step is a component of remote sensing algorithms for scaling gross primary production (GPP) and net primary production (NPP) over regional to global domains. For the purposes of calibrating and validating the light use efficiency (εg) algorithms, the components of εg{\textendash} absorbed photosynthetically active radiation (APAR) and ecosystem GPP {\textendash} must be measured in a variety of environments. Micrometeorological and mass flux measurements at eddy covariance flux towers can be used to estimate APAR and GPP, and the emerging network of flux tower sites offers the opportunity to investigate spatial and temporal patterns in εg at the daily time step. In this study, we examined the relationship of daily GPP to APAR, and relationships of εg to climatic variables, at four micrometeorological flux tower sites {\textendash} an agricultural field, a tallgrass prairie, a deciduous forest, and a boreal forest. The relationship of GPP to APAR was close to linear at the tallgrass prairie site but more nearly hyperbolic at the other sites. The sites differed in the mean and range of daily εg, with higher values associated with the agricultural field than the boreal forest. εg decreased with increasing APAR at all sites, a function of mid-day saturation of GPP and higher εg under overcast conditions. εg was generally not well correlated with vapor pressure deficit or maximum daily temperature. At the agricultural site, a εg decline towards the end of the growing season was associated with a decrease in foliar nitrogen concentration. At the tallgrass prairie site, a decline in εg in August was associated with soil drought. These results support inclusion of parameters for cloudiness and the phenological status of the vegetation, as well as use of biome-specific parameterization, in operational εg algorithms.}, keywords = {LTER-KNZ, Primary production}, doi = {10.1046/j.1365-2486.2003.00573.x}, author = {Turner, D.P. and Urbanski, D. and D. Bremer and Wofsy, S.C. and Meyers, T. and Gower, S.T. and Gregory, M.} } @article {KNZ00810, title = {Can uptake length in streams be determined by nutrient addition experiments? Results from an inter-biome comparison study}, journal = {Journal of the North American Benthological Society}, volume = {21}, year = {2002}, pages = {544 -560}, abstract = {Nutrient uptake length is an important parameter for quantifying nutrient cycling in streams. Although nutrient tracer additions are the preferred method for measuring uptake length under ambient nutrient concentrations, short-term nutrient addition experiments have more frequently been used to estimate uptake length in streams. Theoretical analysis of the relationship between uptake length determined by nutrient addition experiments (SW') and uptake length determined by tracer additions (SW) predicted that SW' should be consistently longer than SW, and that the overestimate of uptake length by SW' should be related to the level of nutrient addition above ambient concentrations and the degree of nutrient limitation. To test these predictions, we used data from an interbiome study of NH4+ uptake length in which 15NH4+ tracer and short-term NH4+ addition experiments were performed in 10 streams using a uniform experimental approach. The experimental results largely confirmed the theoretical predictions: SW' was consistently longer than SW and SW':SW ratios were directly related to the level of NH4+ addition and to indicators of N limitation. The experimentally derived SW':SW ratios were used with the theoretical results to infer the N limitation status of each stream. Together, the theoretical and experimental results showed that tracer experiments should be used whenever possible to determine nutrient uptake length in streams. Nutrient addition experiments may be useful for comparing uptake lengths between different streams or different times in the same stream, however, provided that nutrient additions are kept as low as possible and of similar magnitude.}, keywords = {LTER-KNZ, ammonium, nitrogen limitation, nutrient cycling, nutrient spiraling, stream, uptake length}, doi = {10.2307/1468429}, author = {Mulholland, P.J. and Tank, J.L. and Webster, J.R. and W.B. Bowden and W. K. Dodds and Gregory, S.V. and Grimm, N.B. and Hamilton, S.K. and Johnson, S.L. and Marti, E. and W.H. McDowell and Merriam, J. and Meyer, J.L. and Peterson, B.J. and Valett, H.M. and Wollheim, W.M.} } @phdthesis {KNZ00824, title = {Causes and consequences of species invasion and loss: the role of dominant species and diversity in maintaining ecosystem function}, volume = {PhD Dissertation}, year = {2002}, pages = {1 -148}, school = {Kansas State University}, type = {Ph.D. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ}, author = {M.D. Smith} } @article {KNZ001, title = {Changes in ecosystem structure and function along a chronosequence of restored grasslands}, journal = {Ecological Applications}, volume = {12}, year = {2002}, pages = {1688 -1701}, abstract = {Changes in aboveground vegetation, roots, and soil characteristics were examined from a 12-yr chronosequence of formerly cultivated fields restored to native C4 grasses through the Conservation Reserve Program (CRP). Following 6{\textendash}8 yr in the CRP, the native grasses dominated vegetation composition, and the presence of forbs was negligible. Productivity of the restored grasslands did not exhibit any directional changes with the number of years in the CRP, and productivity was generally higher than native prairie in this region. Over time, the restored grasslands accumulated root biomass of decreasing quality as indicated by increasing root biomass and C:N ratio of roots along the 12-yr chronosequence. Root biomass, root C:N ratio, C storage in roots, and N storage in roots of restored grasslands approached that of native tallgrass prairie within the 12 yr of restoration. Establishment of the perennial vegetation also affected soil physical, chemical, and biological characteristics. Soil bulk density in the surface 10 cm decreased with time since restoration. Total C, microbial biomass C, and C mineralization rates increased as a function of time since restoration. The greatest change in total C occurred in the surface 5 cm, where total C was 26\% greater in 12- vs. 2-yr restored grasslands. Extractable soil nitrate and soil N transformations (i.e., net N mineralization rates and net nitrification rates) declined over the restoration chronosequence, but these values were not representative of steady-state conditions due to the high variability in these measures among the native prairies. Although complete restoration of ecosystem structure and function was not the primary intention of the CRP, this study demonstrates that establishment of the matrix vegetation (i.e., native C4 grasses) drives ecosystem processes in the trajectory of the original system. Moreover, restoration may hasten the recovery of soil C pools relative to formerly cultivated systems undergoing natural succession.}, keywords = {LTER-KNZ, ecosystem, function, grassland, structure}, doi = {10.1890/1051-0761(2002)012[1688:CIESAF]2.0.CO;2}, author = {S.G. Baer and Kitchen, D.J. and John M. Blair and C. W. Rice} } @proceedings {KNZ00934, title = {Climate variability at multiple time scales: implications for productivity in tallgrass prairie}, year = {2002}, pages = {312 -316}, publisher = {American Meteorological Society}, abstract = {Climate is a fundamental driver of biomass productivity in ecosystems. This is especially true for grassland systems, which display greater variability in net primary productivity in response to climate fluctuation than forest, desert, or arctic/alpine systems. Although basic climate/productivity relationships have been studied over shorter time scales, the effect of longer-term climate processes such as El Ni{\~n}o/Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), solar activity cycles, and other quasiperiodic climatic patterns on grassland systems is largely unknown, due to the lack of long term productivity data sets to evaluate against climate data. Here, we examine how variability in temperature and rainfall at a tallgrass prairie site (Konza Prairie Biological Station, KPBS) is related to various teleconnection indices and how these indices may relate to patterns of above ground net primary productivity (ANPP). We use two data sets, a 20 year ANPP data set collected at KPBS and a 108 year precipitation and temperature record (1891-1999) from nearby Manhattan, KS. Patterns of variation are analyzed using period-spectrum analysis and correlation of climate variables to ANPP. Results show that at shorter time scales (one year or less), productivity is influenced by magnitude of precipitation and temperature, but also by the seasonal timing of precipitation events and heat accumulation. Long-term precipitation was influenced on the decadal time scale by the NAO and North Pacific (NP) circulation patterns. Long-term temperature patterns showed strongest periodicities at intradecadal time scales (" 5- 8 years), and correlated most strongly with ENSO indices. Although speculative, our results suggest that the influence of atmospheric teleconnection patterns (and their resulting weather patterns) on tallgrass productivity is indirect. Teleconnection patterns interact to influence both the magnitude and seasonal distribution of temperature and precipitation. The interplay of these variations in weather appears to exert significant control over tallgrass ANPP.}, keywords = {LTER-KNZ}, url = {https://ams.confex.com/ams/15BioAero/techprogram/paper_48840.htm}, author = {Goodin, D.G. and Fay, P.A. and McHugh, M.J.} } @article {KNZ00819, title = {Clone size of Andropogon gerardii Vitman (Big Bluestem) at Konza Prairie, Kansas}, journal = {American Midland Naturalist}, volume = {147}, year = {2002}, pages = {295 -304}, abstract = {Clone size of plants of Andropogon gerardii from Konza Prairie Biological Station, Manhattan, Kansas was estimated from spatial patterns of genetic variation, using proteins detected by starch gel electrophoresis and DNA content (ploidy) measured by flow cytometry. Unique multi-locus protein banding patterns and differences in ploidy were used to exclude plants as members of the same clone. Individual clones averaged about 2 m in diameter and areas of prairie of 100 m2 were calculated to contain an average of 31.8 genetic individuals.}, keywords = {LTER-KNZ}, doi = {10.1674/0003-0031(2002)147[0295:CSOAGV]2.0.CO;2}, author = {Keeler, K.H. and Williams, C.F. and Vescio, L.S.} } @article {KNZ0012, title = {Comparisons of nitrification and denitrification in prairie and agriculturally influenced streams}, journal = {Ecological Applications}, volume = {12}, year = {2002}, pages = {998 -1009}, abstract = {Whole-stream nitrification and denitrification rates were calculated from field incubation studies of representative substrata in Kings Creek and Shane Creek watersheds at the Konza Prairie Biological Station, Kansas, USA. Substrata from a relatively pristine upstream and an agriculturally influenced downstream reach were measured in both watersheds. Rates were scaled to the whole stream by the mass of each substratum in the stream reach. Substrata sampled included epilithon, leaf packs and wood (coarse benthic organic matter, CBOM), filamentous green algae, bryophytes, fine benthic organic matter (FBOM), and suspended particulate organic matter. Upstream sites had significantly lower nitrification and denitrification rates than downstream sites. Nitrification rates were dominated by nitrification associated with epilithon and filamentous green algae. Downstream sites had a higher proportion of nitrification occurring in the water column relative to upstream sites. Whole-stream denitrification was dominated by denitrification associated with FBOM and CBOM and was higher downstream. Water column ammonium (NH4+) and nitrate (NO3-) concentrations were correlated with whole-stream nitrification rates but not whole-stream denitrification rates. Whole-stream nitrification rates were positively correlated with whole-stream denitrification rates, being coupled at the whole-stream level, but not at the substratum level. Relative to the amount of NO3- produced through nitrification, the proportion of NO3- denitrified was 1.4{\textendash}4.6 times greater in the downstream sites compared to the upstream sites, but the proportion of the in-stream NO3- load denitrified was \~{}10 times greater in the upstream sites. These data indicate that changes in stream nitrogen cycling related to increased dissolved inorganic nitrogen concentrations do not result in a large enough increase in denitrification (the stream{\textquoteright}s capacity to retain nitrogen) to compensate for the increased nitrogen loading. Data also suggest that whole-stream nitrification and denitrification may be decoupled at the reach level by factors that decrease habitat heterogeneity (the variety of substrata types) in stream channels. This indicates that anthropogenic disturbances of small streams, such as channelization and removal of riparian vegetation, would be expected to decrease the capacity of streams to retain nitrogen.}, keywords = {LTER-KNZ, nitrification, prairie, stream}, doi = {10.1890/1051-0761(2002)012[0998:CONADI]2.0.CO;2}, author = {Kemp, M.J. and W. K. Dodds} } @article {KNZ00807, title = {A cross-system comparison of bacterial and fungal biomass in detritus pools of headwater streams}, journal = {Microbial Ecology}, volume = {43}, year = {2002}, pages = {55 -66}, keywords = {LTER-KNZ}, doi = {10.1007/s00248-001-1020-x}, author = {Findlay, S.E.G. and Tank, J. and Dye, S. and Vallett, H.M. and Mulholland, P.J. and W.H. McDowell and Johnson, S. and Hamilton, S.K. and Edmonds, J. and W. K. Dodds and W.B. Bowden} } @article {KNZ00779, title = {C3 woody plant expansion in a C4 grassland: are grasses and shrubs functionally distinct?}, journal = {American Journal of Botany}, volume = {88}, year = {2001}, pages = {1818 -1823}, abstract = {

The expansion of C3 shrubs into C4-dominated tallgrass prairies represents a fundamental shift in growth-form dominance accompanied by changes in resource acquisition and use. We assessed these changes by comparing the ecophysiological traits of the dominant C4 grass Andropogon gerardii, with traits of three C3 invasive shrub species, Cornus drummondii, Prunus americana, and Rhus glabra. We tested the hypothesis that ecophysiological traits of the shrubs would be similar within this growth form but distinct from grasses and that these species would conform to the two-layer soil water model. Photosynthetic rates in R. glabra were similar to A. gerardii and higher than in the other two shrubs, while water use efficiency was markedly greater in A. gerardii. Among all species, midday xylem pressure potentials (XPP) were distinctly lower (70\%) for P. americana, but were similar among the other species. Predawn XPP was related to soil water at shallow depths for A. gerardii (r2 = 0.59) and P. americana (r2 = 0.62), and to deeper soil moisture for R. glabra (r2 = 0.63); there was no relationship for C. drummondii at any soil depth. Thus, a simple two-layer soil water model for partitioning shrub/grass resource acquisition was not appropriate for this grassland. We conclude that these shrubs could not be considered functional equivalents from an ecophysiological perspective, nor were they, as a group, distinct from A. gerardii in resource acquisition and use

}, keywords = {LTER-KNZ}, url = {http://www.amjbot.org/cgi/content/abstract/88/10/1818}, author = {McCarron, J.K. and Alan K. Knapp} } @article {KNZ00864, title = {Carbon and water relations of juvenile Quercus species in tallgrass prairie}, journal = {Journal of Vegetation Science}, volume = {12}, year = {2001}, pages = {807 -816}, abstract = {In ecosystems where environments are extreme, such as deserts, adult plant species may facilitate the establishment and growth of seedlings and juveniles. Because high temperatures and evaporative demand characterize tall-grass prairies of the central United States (relative to forests), we predicted that the grassland-forest ecotone, by minimizing temperature extremes and moderating water stress, may function to facilitate the expansion of Quercus species into undisturbed tall-grass prairie. We assessed the carbon and water relations of juvenile Quercus macrocarpa and Q. muhlenbergii, the dominant tree species in gallery forests of northeast Kansas, in ecotone and prairie sites. To evaluate the potentially competitive effects of neighboring herbaceous biomass on these oaks, juveniles (< 0.5 m tall) of both species also were subjected to either: (1) removal of surrounding above-ground herbaceous biomass, or (2) control (prairie community intact) treatments. Herbaceous biomass removal had no significant effect on gas exchange or water relations in these oak species in either the prairie or the ecotone environment. Although the ecotone did alleviate some environmental extremes, photosynthetic rates and stomatal conductance were ca. 20 \% higher (p < 0.05) in both oaks in prairie sites vs. the ecotone. Moreover, although leaf temperatures on average were higher in oaks in the prairie, high leaf temperatures in the ecotone had a greater negative effect on photosynthesis. These data suggest that the grassland-forest ecotone did not facilitate the growth of Quercus juveniles expanding into this grassland. Moreover, the carbon and water relations of juvenile oaks in the prairie appeared to be unaffected by the presence of the dominant C4 grasses.}, keywords = {LTER-KNZ, Ecotone, Facilitation, forest expansion, Quercus, tallgrass prairie}, doi = {10.2307/3236868}, author = {Fay, P.A. and Carlisle, J.D. and Danner, B.T. and Lett, M.S. and McCarron, J.K. and Stewart, C. and Alan K. Knapp and John M. Blair and Scott. L. Collins} } @article {KNZ00772, title = {Centimeter-scale patterns of oxygen concentrations related to nitrification in prairie stream substrate}, journal = {Journal of the North American Benthological Society}, volume = {20}, year = {2001}, pages = {347 -357}, abstract = {Dissolved oxygen (O2) was measured with microelectrodes in shallow subsurface microsites in a prairie stream and related to rates of nitrification determined in the laboratory using the nitrapyrin method. Substrata sampled included diatom mats, leaves and wood (coarse benthic organic matter, CBOM), filamentous green algae, bryophytes, and fine benthic organic matter (FBOM). Significant differences in O2 concentrations were found among the substrata, with anoxic zones occurring primarily in FBOM from deep pool sediments and CBOM from litter accumulations. Filamentous green algae and bryophytes had average O2 concentrations near saturation and intermediate rates of nitrification. Diatom mats had the highest concentrations of O2 (up to several times saturation) and the highest rates of nitrification. In the summer, O2 concentrations were above saturation in epilithon and filamentous green algal mats. Nitrification rates were highest in epilithon and filamentous green algae samples taken in the spring and autumn. A significant positive relationship between nitrification rates and O2 concentration was observed in all seasons except summer. These data suggest that O2 concentration could control nitrification in prairie streams.}, keywords = {LTER-KNZ, Algae, microelectrodes, N cycling, nitrification, O2 concentration, streams, tallgrass prairie}, doi = {10.2307/1468033}, author = {Kemp, M.J. and W. K. Dodds} } @phdthesis {KNZ00753, title = {Changes in ecosystem function and effects of environmental complexity on foristic diversity during tallgrass prairie restoration}, volume = {PhD Dissertation}, year = {2001}, pages = {1 -204}, school = {Kansas State University}, type = {Ph.D. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ, tallgrass prairie}, author = {S.G. Baer} } @phdthesis {KNZ00855, title = {Changes in soil carbon dynamics during juniper expansion into tallgrass prairie}, volume = {PhD Dissertation}, year = {2001}, pages = {1 -137}, school = {Kansas State University}, type = {Ph.D. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ, tallgrass prairie}, author = {Smith, D.L.} } @article {KNZ003, title = {A comparison of the trophic ecology of crayfish (Orconectes nais (Faxon) and Orconectes neglectus (Faxon)) and central stonerollers (Compostoma anomalum (Rafinesque)): omnivory in a tallgrass prairie stream}, journal = {Hydrobiologia}, volume = {462}, year = {2001}, pages = {131 -144}, abstract = {Omnivorous fish, such as the central stoneroller minnow (Campostoma anomalum(Rafinesque)), and crayfish often play important roles in the trophic dynamics of streams. The trophic role of these two omnivores has not been compared within a system even though they both consume algae, detritus and invertebrates and often co-occur in streams in the Midwestern United States. Natural abundance of 15N and 13C isotopes and a whole stream 15N-labeled ammonium chloride release were used to compare the trophic ecology of the central stoneroller minnow (Campostoma anomalum (Rafinesque)) and two species of crayfish (Orconectes neglectus (Faxon) and Orconectes nais (Faxon)) in a tallgrass prairie stream. The δ15N and δ13C values of Orconectes spp. were more similar to coarse benthic organic matter (CBOM) and filamentous green algae than to invertebrates, fine benthic organic matter (FBOM), and periphyton. Values for δ15N and δ13C in C. anomalum were more similar to grazer and collector invertebrates and filamentous green algae than to FBOM and periphyton. Results from a 15N tracer release also indicated a portion of algae and/or invertebrates were a component of nitrogen assimilated in Orconectes spp. and C. anomalum diets. Gut contents of C. anomalum were also analyzed. In contrast to stable isotope data, amorphous detritus was a significant component of C. anomalum guts, followed by diatoms and filamentous green algae. A significant percentage of invertebrate material was found in C. anomalum guts sampled in the spring. Experiments were conducted in artificial streams to determine if Orconectes spp. and C. anomalum could reduce epilithic algal biomass in small streams. Algal biomass on clay tile substrata was decreased relative to controls in artificial stream channels containing O. neglectus (3.4 fold, p=0.0002), C. anomalum (2.1 fold, p=0.0012), and both species combined (3.0 fold, p=0.0003). Results indicate that Orconectes spp. are functioning more as algal and detrital processors than as predators in Kings Creek. Isotope and gut content data show that C. anomalum includes invertebrates as well as algae and detritus in its diet. Both species have the potential to affect algal biomass and are important omnivores in the stream food web.}, keywords = {LTER-KNZ, food webs, gut analysis, Herbivory, omnivory, Stable isotopes}, doi = {10.1023/A:1013182100150}, author = {Evans-White, M.A. and W. K. Dodds and Gray, L. and Fritz, K.M.} } @article {KNZ00769, title = {Constraint to adaptive evolution in response to global warming}, journal = {Science}, volume = {294}, year = {2001}, pages = {151 -154}, abstract = {We characterized the genetic architecture of three populations of a native North American prairie plant in field conditions that simulate the warmer and more arid climates predicted by global climate models. Despite genetic variance for traits under selection, among-trait genetic correlations that are antagonistic to the direction of selection limit adaptive evolution within these populations. Predicted rates of evolutionary response are much slower than the predicted rate of climate change.}, keywords = {LTER-KNZ}, doi = {10.1126/science.1063656}, author = {Etterson, J.R. and Shaw, R.G.} } @article {KNZ00783, title = {Control of nitrogen export from watersheds by headwater streams}, journal = {Science}, volume = {292}, year = {2001}, pages = {86 -90}, abstract = {A comparative 15N-tracer study of nitrogen dynamics in headwater streams from biomes throughout North America demonstrates that streams exert control over nutrient exports to rivers, lakes, and estuaries. The most rapid uptake and transformation of inorganic nitrogen occurred in the smallest streams. Ammonium entering these streams was removed from the water within a few tens to hundreds of meters. Nitrate was also removed from stream water but traveled a distance 5 to 10 times as long, on average, as ammonium. Despite low ammonium concentration in stream water, nitrification rates were high, indicating that small streams are potentially important sources of atmospheric nitrous oxide. During seasons of high biological activity, the reaches of headwater streams typically export downstream less than half of the input of dissolved inorganic nitrogen from their watersheds.}, keywords = {LTER-KNZ}, doi = {10.1126/science.1056874}, author = {Peterson, B.J. and Wollheim, W.M. and Mulholland, P.J. and Webster, J.R. and Meyer, J.L. and Tank, J.L. and Marti, E. and W.B. Bowden and Valett, H.M. and Hershey, A.E. and W.H. McDowell and W. K. Dodds and Hamilton, S.K. and Gregory, S. and Morrall, D.D.} } @article {KNZ00752, title = {Carbon dynamics and microbial activity in tallgrass prairie exposed to elevated CO2 for 8 years}, journal = {Plant and Soil}, volume = {227}, year = {2000}, pages = {127 -137}, abstract = {Alterations in microbial mineralization and nutrient cycling may control the long-term response of ecosystems to elevated CO2. Because micro-organisms constitute a labile fraction of potentially available N and are regulators of decomposition, an understanding of microbial activity and microbial biomass is crucial. Tallgrass prairie was exposed to twice ambient CO2 for 8 years beginning in 1989. Starting in 1991 and ending in 1996, soil samples from 0 to 5 and 5 to 15 cm depths were taken for measurement of microbial biomass C and N, total C and N, microbial activity, inorganic N and soil water content. Because of increased water-use-efficiency by plants, soil water content was consistently and significantly greater in elevated CO2 compared to ambient treatments. Soil microbial biomass C and N tended to be greater under elevated CO2 than ambient CO2 in the 5{\textendash}15 cm depth during most years, and in the month of October, when analyzed over the entire study period. Microbial activity was significantly greater at both depths in elevated CO2 than ambient conditions for most years. During dry periods, the greater water content of the surface 5 cm soil in the elevated CO2 treatments increased microbial activity relative to the ambient CO2 conditions. The increase in microbial activity under elevated CO2 in the 5{\textendash}15 cm layer was not correlated with differences in soil water contents, but may have been related to increases in soil C inputs from enhanced root growth and possibly greater root exudation. Total soil C and N in the surface 15 cm were, after 8 years, significantly greater under elevated CO2 than ambient CO2. Our results suggest that decomposition is enhanced under elevated CO2 compared with ambient CO2, but that inputs of C are greater than the decomposition rates. Soil C sequestration in tallgrass prairie and other drought-prone grassland systems is, therefore, considered plausible as atmospheric CO2 increases.}, keywords = {LTER-KNZ, elevated CO2, microbial activity, Microbial biomass, Soil C and N, soil water}, doi = {10.1023/A:1026590001307}, author = {Williams, M.A. and C. W. Rice and Owensby, C.E.} } @mastersthesis {KNZ00748, title = {Comparative ecology of the C4 grassland co-dominants Andropogon gerardii and Sorghastrum nutans}, volume = {MS Thesis}, year = {2000}, pages = {1 -85}, school = {Kansas State University}, type = {M.S. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ}, author = {Silletti, A.M.} } @mastersthesis {KNZ00733, title = {A comparison of the functional role of crayfishes and central stonerollers in a tallgrass prairie stream}, volume = {MS Thesis}, year = {2000}, pages = {1 -96}, school = {Kansas State University}, type = {M.S. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ, tallgrass prairie}, author = {Evans-White, M.A.} } @article {KNZ00671, title = {Changes in enzyme activities and microbial biomass of tallgrass prairie soil as related to burning and nitrogen fertilization}, journal = {Soil Biology \& Biochemistry}, volume = {31}, year = {1999}, pages = {769 -777}, abstract = {Microbial biomass and enzyme activities are affected by management practices and can be used as sensitive indicators of ecological stability. Microbial biomass C (MBC), microbial biomass N (MBN) and eight enzyme activities involved in the cycling of C, N, P and S were studied in the surface (0{\textendash}5 cm) of an Irwin silty clay loam soil (fine, mixed, mesic, Pachic Arguistoll) in a tallgrass prairie ecosystem. Treatments of annual spring burning and N fertilization were initiated in 1986 and encompassed: (1) unburned{\textendash}unfertilized, (2) burned{\textendash}unfertilized, (3) burned{\textendash}fertilized, and (4) unburned{\textendash}fertilized. Activities of dehydrogenase, β-glucosidase, urease, deaminase, denitrifying enzyme, acid phosphatase, alkaline phosphatase, and arylsulfatase were assayed. Long-term burning and N fertilization of the tallgrass prairie soil reduced MBC and MBN relative to the unburned{\textendash}unfertilized treatment. The effects of burning and N fertilization varied among the enzymes and the time of sampling. Long-term burning significantly (P<0.05) increased activities of urease and acid phosphatase, but decreased activities of β-glucosidase, deaminase and alkaline phosphatase. Long-term N fertilization significantly increased activities of β-glucosidase and acid phosphatase but decreased urease activity. This study found that several soil enzyme activities can be used as indicators of ecological changes caused by N fertilization and long-term burning management practices. The relevance of these changes in surface soil to the long-term sustainability of this ecosystem needs further evaluation.}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.1016/S0038-0717(98)00177-1}, author = {Ajwa, H.A. and Dell, C.J. and C. W. Rice} } @phdthesis {KNZ00702, title = {The comparative floral ecology of seven species of Onagraceae in native tallgrass prairie (pollination)}, volume = {PhD Dissertation}, year = {1999}, school = {Saint Louis University}, type = {Ph.D. Thesis}, address = {Saint Louis, MO}, abstract = {

Seven species of Onagraceae, Tribe Onagreae, occur at sites in Konza Prairie Research Natural Area and Tuttle Creek Reservoir Dam area, controlled by the Kansas Army Corp of Engineers. Three species bloom in the Spring and four species bloom from mid-Summer into Fall. The Spring group displays flowers in an unstratified pattern with fewer, but larger, flowers per stem per day, while the mid-Summer group displays several smaller flowers per day on numerous inflorescences in a stratified, three dimensional pattern on tall plants. Both groups demonstrate high fruit set in three breeding systems. Self-pollinating and self-compatible \<italic\>Calylophus serrulatus\</italic\> (Nutt.) Raven attracts a diverse forager assemblage, but only small bees less than 10mm. carry adequate pollen loads. Outcrossing vernal species include \<italic\>Oenothera macrocarpa \</italic\> Nutt., and \<italic\>O. speciosa\</italic\> Nutt. Both species open at night and attract night-flying moths, but \<italic\>O. macrocarpa\</italic\> is the preferred nectar reward source for Sphingidae, of which six species foraged in a three tiered, niche-partitioning group. Samples of pre and post-forager levels of nectar reserves indicate that in 1995 and 1996, shorter tongued sphingids were the major or foragers. \<italic\>O. biennis\</italic\> L., was weedy and cleistogamous, \<italic\>Gaura longiflora\</italic\> Spach, was weedy but outcrossing, and attracted small to medium sized bees in the morning. \<italic\> G. parviflora\</italic\> Dougl., was a self-pollinating and self-compatible weed, and \<italic\>Stenosiphon linifolius\</italic\> (Nutt.) Heynh. was an outcrosser pollinated mostly by small bees less than 6mm long

}, keywords = {LTER-KNZ, tallgrass prairie}, author = {Nonnenmacher, H.F.} } @article {KNZ00695, title = {Comparison of common cytotypes of Andropogon gerardii (Andropoganeae, Poaceae)}, journal = {American Journal of Botany}, volume = {86}, year = {1999}, pages = {974 -979}, keywords = {LTER-KNZ}, author = {Keeler, K.H. and Davis, G.A.} } @article {KNZ00689, title = {The core-satellite species hypothesis provides a theoretical basis for Grimes classification of dominant subordinate, and transient species}, journal = {Journal of Ecology}, volume = {87}, year = {1999}, pages = {1064 -1067}, keywords = {LTER-KNZ}, doi = {10.1046/j.1365-2745.1999.00424.x}, author = {D.J. Gibson and Ely, J.S. and Scott. L. Collins} } @article {KNZ00618, title = {Carbon and nitrogen mineralization in tallgrass prairie and agricultural soil profiles}, journal = {Soil Science Society of America Journal}, volume = {62}, year = {1998}, pages = {942 -951}, abstract = {In situ mineralization of N may contribute significantly to total inorganic-N pools deep in the soil profile. We conducted long-term laboratory incubation experiments to evaluate the net C and N mineralization in soils collected from various depths in tallgrass prairie and agricultural fields of the same geological materials and soil type. Samples were packed to a bulk density of 1.4 g cm-3 in 5-cm-diameter by 10-cm-long cores. The cores were incubated at 35{\textdegree}C for 40 wk in sealed containers. Net C mineralization was measured by evolved CO2, and N mineralized was measured by periodic leaching with NH+4 and NO-3 measured in the leachate. Carbon and N mineralization in the surface horizon were greater in the tallgrass prairie than in the agricultural soil. In both the tallgrass prairie and agricultural soil profiles, C mineralization was least at the water-table depth. Carbon mineralization was described by a first-order kinetic model, but N mineralization was described better by a consecutive (sigmoidal) reaction model. At most depths, the ratios of potentially mineralizable organic C (C0) to total organic C (C0/TOC) and potentially mineralizable organic N (N0) to total N (N0/TN) were greater in the agricultural soil profile than in the tallgrass prairie soil profile. The C0 and N0 in the surface soil (0{\textendash}0.2 m) represented 11.6 and 12.2\% of the total organic C and N pools for the tallgrass prairie soil profile, respectively, and 21.0 and 10.2\% of the total organic C and N pools for the agricultural soil profile. Management practices affected the mineralization potentials and rates of both the surface and subsurface soils.}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.2136/sssaj1998.03615995006200040014x}, author = {Ajwa, H.A. and C. W. Rice and Sotomayor, D.} } @inbook {KNZ00665, title = {Climate change, elevated CO2 and predictive modeling: Past and future climate change scenarios for the tallgrass prairie}, booktitle = {Grassland Dynamics: Long-Term Ecological Research in Tallgrass Prairie}, year = {1998}, pages = {283 -300}, publisher = {Oxford University Press}, organization = {Oxford University Press}, address = {New York}, keywords = {LTER-KNZ, tallgrass prairie}, url = {http://www.colostate.edu/Depts/GDPE/Distinguished_Ecologists/2005/Hayden/grassland\%20dynamics\%20ch16.pdf}, author = {Seastedt, T.R. and Hayden, B.P. and Owensby, C.E. and Alan K. Knapp}, editor = {Alan K. Knapp and J. M. Briggs and D.C. Hartnett and Scott. L. Collins} } @article {KNZ00602, title = {A case of senescence for the white-footed mouse?}, journal = {The Southwestern Naturalist}, volume = {42}, year = {1997}, pages = {236 -237}, keywords = {LTER-KNZ}, author = {McMillan, B.R. and Kaufman, G.A. and D.W. Kaufman} } @inbook {KNZ00591, title = {Comparative ecology of native and introduced ungulates}, booktitle = {Ecology and Conservation of Great Plains Vertebrates}, year = {1997}, pages = {72 -101}, publisher = {Springer-Verlag}, organization = {Springer-Verlag}, address = {New York}, abstract = {The defining period of coevolution among Great Plains plant and ungulate species occurred during the past 12,000 years (Mack and Thompson 1982, Axelrod 1985). In the late Pleistocene and early Holocene, a diverse array of large grazers and browsers were reduced to a much smaller group of ungulate species represented by bison (Bison bison), pronghorn (Antilocapra americana), deer (Odocoileus hemionus and O. virginianus), and elk (Cervus canadensis). These changes occurred in the presence of nomadic humans from the Asian steppe who were immigrating to the Great Plains during the same time. The landscape was characterized by gently rolling interfluvial surfaces covered with perennial herbaceous vegetation. These exposed grasslands were periodically interrupted by more protected wetland, riparian woodland, or scarp woodland habitats. Although wetlands and woodlands occupied less than 7 and less than 3\% of the Great Plains, respectively (National Wetlands Inventory, and Nebraska Natural Heritage Program data bases), the heterogeneity that they created at landscape scales played a major role in determining the distribution and abundance of native ungulates. Extreme cold and heat, drought, flood, fire, wind, and countless biotic interactions caused locally short-term fluctuations in ungulate populations and long-term shifts in landscape features. These dynamic temporal changes were overlayed on a multi-scale spatial mosaic. Native ungulates were adapted to this landscape.}, keywords = {LTER-KNZ}, doi = {10.1007/978-1-4757-2703-6_4}, author = {D.C. Hartnett and Steuter, A.A. and Hickman, K.R.}, editor = {Knopf, F.L. and Samson, F.B.} } @article {KNZ00613, title = {Contingent effects of plant species on soils along a regional moisture gradient in the Great Plains}, journal = {Oecologia}, volume = {110}, year = {1997}, pages = {393 -402}, abstract = {The central grassland region of the United States encompasses major gradients in temperature and precipitation that determine the distribution of plant life forms, which in turn may influence key ecosystem processes such as nutrient cycling and soil organic matter dynamics. One such gradient is the threefold increase in precipitation from the eastern Colorado shortgrass-steppe, in the rain shadow of the Rocky Mountains, to the tallgrass prairie in eastern Kansas. We investigated the relative roles of plant species and plant cover in influencing soil C and N cycling in three sites along this gradient. Plant cover (i.e., the presence or absence of an individual plant) was relatively more important than plant species in explaining variability in soil properties at the dry site, the Central Plains Experimental Range in{\textvisiblespace}northeastern Colorado. However, plant species explained relatively more of the variability in soil properties than did plant cover at the two wetter sites, Hays and Konza, in central and eastern Kansas. The wetter sites had more continuous plant cover, resulting in less plant-cover-induced variation in soil C and N, than did the dry site, which had distinct patches of bare ground. Plant species at the wetter sites had higher and more variable levels of tissue C:N than plant species at the dry site, due to both within species changes and changes in species composition. Aboveground tissue C:N was better correlated with net nitrogen mineralization rates at the wet sites than the dry site. Thus, tissue chemistry appears to exert more control on nitrogen dynamics at the wet than the dry sites. The results suggest that plant species traits that are relevant to nutrient cycling (e.g., tissue C:N ratios, spatial patterns, productivity) reflect environmental limitations as well as species{\textquoteright} physiological potentials. Furthermore, a dominant environmental driver such as precipitation may ameliorate or exaggerate the importance of individual species traits for nutrient cycling.}, keywords = {LTER-KNZ, grassland, Litter quality, Plant-soil interactions, Soil carbon, Soil nitrogen}, doi = {10.1007/s004420050174}, author = {Vinton, M.A. and Burke, I.C.} } @article {KNZ00592, title = {The contribution of drought-related decreases in foliar nitrogen concentration to decreases in photosynthetic capacity during and after drought in prairie grasses}, journal = {Physiologia Plantarum}, volume = {101}, year = {1997}, pages = {173 -182}, abstract = {While stomatal closure usually limits photosynthesis during drought, our previous results suggest that drought-related decreases in foliar nitrogen concentration (NL) limit photosynthesis during recovery from drought in prairie grasses. Here we estimate the importance of decreases in NL to decreased photosynthetic capacity (PScap) during drought and a subsequent recovery period in three perennial C4 prairie grasses. PScap (O2 evolution at light and CO2 saturation) decreased 69 to 78\% during drought in these grasses, and full recovery of PScap required 8 to 12 days, until younger leaves were expanded or older leaves were repaired, depending on species. Decreases in NL explained 38 to 51\% of the loss of PScap during drought and accounted for 51 to 69\% of the total loss of PScap integrated over the post-drought recovery period. N-related loss of PScap appeared to result more from decreases in ribulose-1,5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39), phosphoenolpyruvate carboxylase (4.1.1.31), and other soluble photosynthetic enzymes, than from decreases in thylakoid N-containing compounds. Decreases in quantum yield of O2 evolution and Fv/Fm (variable-to-maximum fluorescence of dark-adapted leaves) during drought were small, so we assumed that little damage to photsystem II (PSII) and thylakoid membrane function occurred. Further, F0 (minimum F) decreased or remained unchanged, dark F0 was greater than light F0, and decreases in photochemical quenching (the fraction of oxidized PSII) were reversed within 1{\textendash}3 days after drought. Therefore, prolonged increases in non-photochemical quenching (qn; thermal dissipation of excess light energy) during and after drought were indicative of protective downregulation and were likely associated with disproportionate loss of soluble photosynthetic proteins during drought. In support of this, post-drought recovery of qn paralleled recovery of NL and PScap. Thus, in C4 prairie grasses, loss of PScap during drought is largely the result of decreases in shoot NL and of associated protective downregulation, decreasing carbon assimilation for 1{\textendash}2 weeks after drought.}, keywords = {LTER-KNZ, Drought, nitrogen, photosynthesis, prairie grasses, water stress}, doi = {10.1111/j.1399-3054.1997.tb01834.x}, author = {Heckathorn, S.A. and DeLucia, E.H. and Zielinski, R.E.} } @phdthesis {KNZ00951, title = {Clonal biology of the caespitose grass Schizachyrium scoparium: mechanisms of intraclonal regulation and ecological success}, volume = {PhD Dissertation}, year = {1996}, pages = {1 -108}, school = {Texas A\&M University}, type = {Ph.D. Thesis}, address = {College Station, TX}, keywords = {LTER-KNZ}, author = {Derner, J.D.} } @article {KNZ00577, title = {Comparisons of water consumption between two grassland emberizids}, journal = {The Prairie Naturalist}, volume = {27}, year = {1996}, pages = {215 -222}, keywords = {LTER-KNZ}, author = {Zimmerman, J.L.} } @article {KNZ00523, title = {Comparative gas exchange and nitrogen responses of the dominant C4 grass, Andropogon gerardii, and five C3 forbs to fire and topographic position in tallgrass prairie during a wet year}, journal = {International Journal of Plant Science}, volume = {156}, year = {1995}, pages = {216 -226}, abstract = {High plant species diversity in tallgrass prairie results not from a large number of grass species but, rather, from a large number of forb (nongrass, herbaceous) species. Although morphological characteristics of tallgrass prairie forbs differ strongly from those of the grasses and their patterns of abundance vary substantially with burning regime and topographic position, comparatively little is known about the ecology of persistent tallgrass prairie forbs. We measured leaf-level physiological characteristics of the dominant C4 grass, Andropogon gerardii, and five co-occurring C3 forb species in response to burning regime and topographic position to determine if there were either absolute or seasonal differences in resource utilization patterns that could contribute to the patterns of forb distribution and abundance in tallgrass prairie. In a wet year, neither fire nor topographic position affected leaf-level physiological characteristics in the grass and forbs studied, and thus responses were not consistent with extant patterns of forb abundance (greater forb abundance in unburned and upland sites). Water use efficiency in A. gerardii was 40\%-170\% greater and foliar N concentration was consistently lower in the grass than in the forbs, but there were no distinct or consistent differences between the grass and forbs in maximum rates of photosynthesis and stomatal conductance or xylem pressure potential. Moreover, seasonal patterns of gas exchange in forbs and the grass were not different, as might be expected when comparing C3 and C4 species. These results indicate that, when assessed at the leaf level, responses of these prairie plants to fire or topographic position during a wet year are not indicative of their success in these sites. However, seasonal water stress is a typical feature of the tallgrass prairie environment and water use patterns indicate that the prevalence of soil moisture limitations in most years may be a key factor influencing plant distribution and success in this ecosystem.}, keywords = {LTER-KNZ, tallgrass prairie}, url = {http://www.jstor.org/stable/2474960}, author = {Turner, C.T. and Kneisler, J.R. and Alan K. Knapp} } @inbook {KNZ00508, title = {Comparison of spatial and temporal variability of ecological parameters from 12 North American ecosystems}, booktitle = {Evaluating And Monitoring The Health Of Large-Scale Ecosystems, NATO ASI series, Vol I 28}, year = {1995}, pages = {359 -383}, publisher = {Springer-Verlag}, organization = {Springer-Verlag}, address = {Berlin}, keywords = {LTER-KNZ}, author = {Kratz, T.K. and Magnuson, J.J. and Bayley, P. and Benson, B.J. and Berish, C.W. and Bledsoe, C.S. and Blood, E.R. and Bowser, C.J. and Carpenter, S.R. and Cunningham, G.L. and Dahlgren, R. and Frost, T.M. and Halfpenny, J.C. and Hansen, J. and Heisey, D. and Inouye, R.S. and D.W. Kaufman and McKee, A. and Yarie, J.A.}, editor = {Rapport, D.J. and Gaudet, C.L. and Calow, P.} } @inbook {KNZ00488, title = {The coyote: an indicator species of environmental change on the great plains}, booktitle = {Our living resources: a report to the nation on the distribution, abundance, and health of U.S. plants, animals, and ecosystems}, year = {1995}, pages = {305 -307}, publisher = {U.S. Department of the Interior, National Biological Service}, organization = {U.S. Department of the Interior, National Biological Service}, address = {Washington, DC}, keywords = {LTER-KNZ}, author = {Gipson, P.S. and Brillhart, D.E.}, editor = {LaRoe, E.T. and Farris, G.S. and Puckett, C.E. and Doran, P.D. and Mac, M.J.} } @mastersthesis {KNZ00470, title = {Characterizing herbivore resistance traits in eight tallgrass prairie grasses}, volume = {MS Thesis}, year = {1994}, pages = {1 -63}, school = {Kansas State University}, type = {M.S. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ, tallgrass prairie}, author = {Thomas, M.A.} } @article {KNZ00422, title = {Changes in microbial populations from eastern woodrat caches}, journal = {Southwestern Naturalist}, volume = {38}, year = {1993}, pages = {30 -35}, abstract = {Change in microbial populations on three plant foods commonly stored over winter by eastern woodrats (Neotoma floridana) was assessed. It was expected that dogwood fruits (Cornus drummondii) would be affected by microbes to a greater degree than ash seed (Fraxinus pennsylvanica) or redbud seed (Cercis canadensis). Results revealed a change in microbial populations over time but dogwood fruit was no more liable to microbial infestation than seeds. One bacterial species was found in high number on all three food types while three species were found on only two of the three foods. Microbial populations from all three test items increased from November to January but March populations were not different from November populations. It is suggested that climatic factors help to control microbial populations on cache foods.}, keywords = {LTER-KNZ}, doi = {10.2307/3671641}, author = {Post, D.M. and Urban, J.E.} } @article {KNZ00423, title = {Characteristics and significance of the caches of eastern woodrats (Neotoma floridana )}, journal = {Journal of Mammalogy}, volume = {74}, year = {1993}, pages = {688 -692}, abstract = {Caches from eastern woodrat (Neotoma floridana) dens were analyzed for plant-species composition, abundance, and energy content. Body mass and sex of den residents and the den volume were measured to determine correlations with energy content of caches. We found no difference between males and females in den volume or energy content of caches. However, a positive correlation existed between body mass of the cache owner and the amount of energy stored in the cache, such that larger individuals had a disproportionately greater reserve of energy stored in caches than did smaller individuals. The disparity suggests that small individuals are forced to forage outside the den more often than large individuals.}, keywords = {LTER-KNZ, caching, dens, eastern woodrats, energy, food storage, Neotoma floridana}, doi = {10.2307/1382290}, author = {Post, D.M. and Reichman, O.J. and Wooster, D.} } @article {KNZ00391, title = {Comparative water relations of seedling and adult Quercus species during gallery forest expansion in tallgrass prairie}, journal = {Forest Ecology and Management}, volume = {56}, year = {1993}, pages = {29 -41}, abstract = {Seasonal patterns in xylem pressure potential (ψ) and stomatal conductance to water vapor (g) were compared between seedlings (1{\textendash}5 years old) invading tallgrass prairie and adult trees of Quercus macrocarpa (Bur oak) and Quercus muehlenbergii (Chinquapin oak) in adjacent gallery forest. Water is often limiting to productivity in the Flint Hills of NE Kansas, thus, we hypothesized that seedlings invading a grassland would have lower ψ and g compared with adult trees, reflecting competitive interactions for water between seedlings and the dominant grasses. We found that ψ was usually lower in adult trees than in older seedlings, but in the very smallest seedlings ψ was significantly reduced compared with mature (greater than 50 years) individuals. Adult and 1- to 2-year-old seedlings had similar g during the season with highest g occurring in older (4- to 5-year-old) seedlings. In general, Q. muehlenbergii had higher ψ and lower g than Q. macrocarpa consistent with reports that Q. muehlenbergii is more drought tolerant. Rapid and extensive root growth characteristic of Quercus seedlings reduced the period of time when seedlings invading prairie must compete with the grasses for water, although water stress may still be an important factor affecting first-year seedlings in this ecosystem. In contrast, strong intraspecific competition for water within mature gallery forests may have reduced ψ and g in forest trees. Thus, the potential for water stress to impact Quercus survival and growth in this drought-prone ecosystem is greatest during establishment and then after forest development is complete. Older seedlings (greater than 4{\textendash}5 years old), saplings and isolated trees within the prairie may experience the least water stress due to a reduction in both inter- and intraspecific competition for water. These data suggest that in the absence of severe fire or drought occurring during the growing season, gallery forests will continye to expand into tallgrass prairie.}, keywords = {LTER-KNZ, Water relations}, doi = {10.1016/0378-1127(93)90101-R}, author = {Bragg, W.K. and Alan K. Knapp and J. M. Briggs} } @article {KNZ00427, title = {Consequences of non-equilibrium resource availability across multiple time scales: the transient maxima hypothesis}, journal = {American Naturalist}, volume = {141}, year = {1993}, pages = {621 -633}, abstract = {Nonequilibrium biotic responses to changes in resource limitation dominate the behavior of tallgrass prairie ecosystems. Rates of leaf photosynthesis on a time scale of minutes, amounts of annual plant productivity, patterns in the productivity of certain consumer groups, and amounts of soil organic matter accumulation over millennia all reflect biotic responses to frequent and recurring shifts in limiting resources. Productivity is higher during a transition period when the relative importance of an essential resource is changing than during an equilibrium interval generated by single resource limitation. These "transient maxima" are both characteristic and easily measurable in the tallgrass prairie because of the unpredictable climate and ecological constraints such as grazing and recurrent fires that modify water, nitrogen, and light availability. Such diverse phenomena as overcompensation for herbivory, the intermediate disturbance hypothesis, maximum levels of productivity observed in successional ecosystems, and widespread nitrogen limitation in terrestrial and aquatic ecosystems can be explained by biotic response to shifts in limiting resources.}, keywords = {LTER-KNZ}, url = {http://www.jstor.org/stable/2462753}, author = {Seastedt, T.R. and Alan K. Knapp} } @phdthesis {KNZ00357, title = {Carbon and nitrogen dynamics and microbial ecology in tallgrass prairie}, volume = {PhD Dissertation}, year = {1992}, pages = {1 -194}, school = {Kansas State University}, type = {Ph.D. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ, tallgrass prairie}, author = {Garcia, F.O.} } @article {KNZ00374, title = {Change in nutrient content of foods stored by eastern woodrats (Neotoma florida)}, journal = {Journal of Mammalogy}, volume = {73}, year = {1992}, pages = {835 -839}, abstract = {

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

}, keywords = {LTER-KNZ}, doi = {10.2307/1382204}, author = {Post, D.M.} } @proceedings {KNZ00353, title = {Characterization of a groundwater community dominated by Asellus tridentata (Isopoda)}, year = {1992}, pages = {91 -99}, keywords = {LTER-KNZ}, author = {Edler, C. and W. K. Dodds} } @booklet {KNZ00379, title = {Collected data of the first ISLSCP field experiment: Volume 2: Satellite Imagery 1987-1989}, year = {1992}, keywords = {LTER-KNZ, ISLSCP}, author = {Strebel, D.E. and Landis, D.R. and Newcomer, J.A. and Elburg-Obler, D. and Meeson, B.W. and Agbu, P.A.} } @booklet {KNZ00381, title = {Collected data of the first ISLSCP field experiment: Volume 3: NS001 Imagery 1987 to 1989}, year = {1992}, keywords = {LTER-KNZ, ISLSCP}, author = {Strebel, D.E. and Landis, D.R. and Newcomer, J.A. and Goetz, S.J. and Meeson, B.W. and Agbu, P.A. and McManus, J.M.P.} } @booklet {KNZ00380, title = {Collected data of the first ISLSCP field experiment: Volume 4: ASAS; PBMR Imagery 1987-1989}, year = {1992}, keywords = {LTER-KNZ, ISLSCP}, author = {Strebel, D.E. and Landis, D.R. and Newcomer, J.A. and Meeson, B.W. and Agbu, P.A. and McManus, J.M.P.} } @article {KNZ00316, title = {Constraints on the growth and allocation patterns of Silphium integrifolium (Asteraceae ) caused by cynipid gall wasps}, journal = {Oecologia}, volume = {88}, year = {1991}, pages = {243 -250}, keywords = {LTER-KNZ}, doi = {10.1007/BF00320818}, author = {Fay, P.A. and D.C. Hartnett} } @phdthesis {KNZ00306, title = {The contribution of mycorrhizal symbiosis to tallgrass prairie}, volume = {PhD Dissertation}, year = {1991}, pages = {1 -73}, school = {Kansas State University}, type = {Ph.D. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ, tallgrass prairie}, author = {Bentivenga, S.P.} } @article {KNZ00337, title = {Controls of nitrogen limitation in tallgrass prairie}, journal = {Oecologia}, volume = {87}, year = {1991}, pages = {72 -79}, abstract = {

The relationship between fire frequency and N limitation to foliage production in tallgrass prairie was studied with a series of fire and N addition experiments. Results indicated that fire history affected the magnitude of the vegetation response to fire and to N additions. Sites not burned for over 15 years averaged only a 9\% increase in foliage biomass in response to N enrichment. In contrast, foliage production increased an average of 68\% in response to N additions on annually burned sites, while infrequencly burned sites, burned in the year of the study, averaged a 45\% increase. These findings are consistent with reports indicating that reduced plant growth on unburned prairie is due to shading and lower soil temperatures, while foliage production on frequently burned areas is constrained by N availability. Infrequent burning of unfertilized prairie therefore results in maximum production response in the year of burning relative to either annually burned or long-term unburned sites. Foliage biomass of tallgrass prairie is dominated by C4 grasses; however, forb species exhibited stronger production responses to nitrogen additions than did the grasses. After four years of annual N additions, forb biomass exceeded that of grass biomass on unburned plots, and grasses exhibited a negative response to fertilizer, probably due to competition from the forbs. The dominant C4 grasses may out-compete forbs under frequent fire conditions not only because they are better adapted to direct effects of burning, but because they can grow better under low available N regimes created by frequent fire. Key words: Andropogon gerardii, fire, nitrogen, prairie, productivity

}, keywords = {LTER-KNZ, fire;soil temperature;tallgrass prairie}, doi = {10.1007/BF00323782}, author = {Seastedt, T.R. and J. M. Briggs and D.J. Gibson} } @article {KNZ00341, title = {Cryptosporidium and Giardia in surface waters in and around Manhattan, Kansas}, journal = {Transaction of the Kansas Academy of Science}, volume = {94}, year = {1991}, pages = {101 -106}, abstract = {

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

}, keywords = {LTER-KNZ}, doi = {10.2307/3627857}, author = {Todd, C.S. and Phillips, M.S. and Marchin, G.L. and Upton, S.J.} } @article {KNZ00275, title = {Contributions of the long-term ecological research program}, journal = {BioScience}, volume = {40}, year = {1990}, pages = {509 -523}, abstract = {

The importance of long-term phenomena in ecology is well documented. Transient responses that extend over decades, or even centuries, are common, such as the gradual changes associated with community succession, soil development, and population of large vertebrates. Other ecological phenomena are infrequent (rare or episodic) events, including such disturbances as floods, hurricanes, wildfires, or volcanic eruptions, and the reproduction of long-lived plant species. Long-term studies are essential to understand such phenomena, as well as for the formation and testing of ecological theory. Research with an extended time perspective is crucial if one accepts the premise that long-term phenomena have a central role in ecological science. Such studies are uncommon despite this obvious need and repeated evidence of the misleading nature of short-term research. Factors contributing to the rarity of long-term studies include difficulties in obtaining sustained financial support and in providing continuing leadership. The National Science Foundation (NSF), responding to this need for support of long-term studies in ecology, initiated a program in Long-Term Ecological Research (LTER) in 1980. This initiative followed an extended planning period involving ecological scientists of varied interests. The LTER now has 17 sites with more than 400 associated scientific personnel

}, keywords = {LTER-KNZ}, doi = {http://www.jstor.org/stable/1311319}, author = {Franklin, J.F. and Bledsoe, C.S. and Callahan, J.T.} } @inbook {KNZ00249, title = {Canopy photosynthesis}, booktitle = {Photosynthesis}, year = {1989}, note = {Published}, pages = {227 -241}, publisher = {Alan R. Liss, Inc}, organization = {Alan R. Liss, Inc}, address = {New York, N.Y}, keywords = {LTER-KNZ}, author = {Norman, J.M. and Polley, W.}, editor = {Briggs, W.R.} } @article {KNZ00218, title = {Carbon isotopes in soils and palaeosols as ecology and palaeoecology indicators}, journal = {Nature}, volume = {341}, year = {1989}, pages = {138 -139}, abstract = {

There are few quantitative techniques in use today for palaeoecological reconstruction in terrestrial depositional systems. One approach to such reconstructions is to estimate the proportion of C3 to C4 plants once present at a site using carbon isotopes from paelaeosol carbonates1-3. Until now, this has been hampered by an inadequate understanding of the relationship between the carbon isotopic composition of modern soil carbonate and coexisting organic matter. Here we have found that the two systematically differ by 14-16\% in undisturbed modern soils. This difference is compatible with isotopic equilibrium between gaseous CO2, and aqueous and solid carbonate species in a soil system controlled by diffusive mass transfer of soil CO2 derived from irreversible oxidation of soil organic matter. Organic matter and pedogenic carbonate from palaeosols of Pleistocene to late Miocene age in Pakistan also differ by 14-16\%. This indicates that diagenesis has not altered the original isotopic composition of either phase, thus confirming their use in palaeoecological reconstruction

}, keywords = {LTER-KNZ}, doi = {10.2307/1940178}, author = {Cerling, T.E. and Quade, J. and Wang, Y. and Bowman, J.R.} } @article {KNZ00216, title = {Comparative analysis of temporal and spatial variability in aboveground production in a deciduous forest and prairie}, journal = {Holarctic Ecology}, volume = {12}, year = {1989}, pages = {130 -136}, abstract = {

Production patterns of tallgrass prairie and adjacent eastern deciduous forest were summarized for a five to seven year period. Each system responded differentially to annual or growing season rainfall and solar energy (measured by pan water evaporation). Overall, forest productivity was negatively correlated with annual precipitation; the prairie exhibited no relationship with precipitation. These differences probably reflect the lack of water limitation of the forest and the \"downstream\" position of the forest. Wood and seed production in the forest were the most variable components measured in our study. Neither variable was related to forest foliage production. Seed production in the prairie was also variable within and between years but was related to prairie foliage production. Prairie seed production was not correlated with seed production of the forest. The two ecosystems respond differentially and independently of each other within the range of climatic variation observed here. Such differences have potential significance to consumers who use both systems for habitat or resources

}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.1111/j.1600-0587.1989.tb00831.x}, author = {J. M. Briggs and Seastedt, T.R. and D.J. Gibson} } @phdthesis {KNZ00244, title = {A comparison of soil hydraulic properties on Konza Prairie burning treatments}, volume = {PhD Dissertation}, year = {1989}, pages = {1 -87}, school = {Kansas State University}, type = {Ph.D. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ, burning}, author = {Klittich, W.M.} } @proceedings {KNZ00229, title = {Correlations between stream insect emergence and densities of insectivorous birds in the tallgrass prairie}, year = {1989}, pages = {263 -265}, publisher = {University of Nebraska Press}, address = {Lincoln, NE}, abstract = {

Previous observations in riprarian habitats of Kings Creek, Konza Prairie Research Natural Area, Kansas indicated that emerging aquatic insects represent a concentrated source of food for insectivorous birds, particularly the flycatcher and gleaner guilds. This hypothesis was tested by concurrent measurments of net insect emergence (total emergence minus adults returning to the stream) and densities of birds at six sampling sites from June to August 1987 and May to June 1988. Significant positive correlations with emergence were found for flycatchers (r=0.93) and gleaners (r=0.91), the two insectivore guilds containing the majority of individuals along Kings Creek. Observations also showed that flycatcher and gleaner populations rapidly respond to temporal changes in insect emergence. Key words: fly catcher, gleaner, bird, aquatic insect, tallgrass prairie, stream, Kansas

}, keywords = {LTER-KNZ, tallgrass prairie}, author = {Gray, L.J.}, editor = {Bragg, T.B. and Stubbendieck, J.} } @article {KNZ00201, title = {Caching behavior by eastern woodrats (Neotoma floridana ) in relation to food perishability}, journal = {Animal Behavior}, volume = {36}, year = {1988}, pages = {1525 -1532}, abstract = {

Two experiments were conducted on eastern woodrats to determine whether the preference for food items gathered for their caches and the sequence of use of items in the cache varied with perishability. In the first experiment, woodrats were given either 2 kg each of two non- perishable items, laboratory chow and bur oak acorns (which they used more than chow), or 2 kg each of preferred, but perishable, grapes and the non-perishable chow. As hypothesized, the woodrats both ate and stored acorns when they were paired with chow (there would be no advantage to either eating or storing the less-used chow). In contrast, when given grapes and chow, the woodrats continued to eat grapes but stored primarily chow. That is, the utility of the items appeared to change depending on whether they were to be eaten or stored. In the second experiment, woodrats were given excess amounts of chow or grapes that were 2, 4, 6, and 8 days old. They ingested chow in the proportions available, as the chow did not spoil with age. However, they consumed grapes in proportions significantly different from those available. It was anticipated that they would eat the oldest grapes first and store the freshest grapes, but neither this pattern nor any other was obvious in relation to the age of the grapes. The results suggest that woodrats discriminate between food items based on their perishability, and vary their decisions about what to ingest and store accordingly

}, keywords = {LTER-KNZ}, doi = {10.1016/S0003-3472(88)80223-9}, author = {Reichman, O.J.} } @mastersthesis {KNZ00174, title = {Canopy net carbon dioxide exchange by burned and unburned tallgrass prairie}, volume = {MS Thesis}, year = {1988}, pages = {1 -76}, school = {Kansas State University}, type = {M.S. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ, tallgrass prairie}, url = {http://krex.k-state.edu/dspace/handle/2097/22236}, author = {Gale, W.J.} } @article {KNZ00186, title = {Causes of fire effects in tallgrass prairie}, journal = {Ecology}, volume = {69}, year = {1988}, pages = {46 -58}, abstract = {

Eleven experimental treatments were applied to 2 x 2 m plots over 2 yr at Konza Prairie Research Natural Area, Riley County, Kansas, to ascertain why burning tallgrass prairie causes increased production and flowering. Warming of the soil in unburned plots resulted in an increase in both total production and flower stalk production of dominant tall grasses, primarily big bluestem (Andropogon gerardii) and Indian grass (Sorghastrum nutans), but the increase was small (34\% increase in biomass; 78\% increase in number of flower stalks) compared with that in burned plots (151\% increase in biomass; 435\% increase in flower stalks). Increased surface light intensity also appears to be a factor affecting changes in productivity following burning as suggested by the combined responses of increased productivity with removal of standing dead, whether by clipping or burning, and decreased productivity with shading. Further, the addition of ammonium nitrate increased yield 41\% and flowering 168\% for the dominant grasses, suggesting that any factor increasing nitrogen availability would affect these vegetative parameters. Neither ash left from burning nor hrating of the soil surface during burning produced detectable effects on subsequent vegetative growth. Different results for some parameters between years and between species suggest that many complex interactions operate to affect the grassland\&$\#$39;s response to burning, but surface light, soil surface temperature, and nitrogen appear to be particularly important factors. Key words: aboveground biomass, bluestem prairie, burning, fire, flowering, soil temperature, tallgrass prairie

}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.2307/1943159}, author = {Hulbert, L.C.} } @mastersthesis {KNZ00192, title = {Community composition and emergence phenology of Chironomidae (Diptera) in prairie streams with different flow regimes}, volume = {MS Thesis}, year = {1988}, pages = {1 -77}, school = {University of Kansas}, type = {M.S. Thesis}, address = {Lawrence, KS}, keywords = {LTER-KNZ}, author = {Kavanaugh, J.L.} } @article {KNZ00173, title = {Community dynamics of prairie grasshoppers subjected to periodic fire: predictable trajectories or random walks in time?}, journal = {Oikos}, volume = {52}, year = {1988}, pages = {283 -292}, abstract = {

Grasshopper communities were sampled by sweep net at six sites in native tallgrass prairie at Konza Prairie, Kansas, USA, in 1982-86 to assess community change from year to year in prairie burned once every four years. Species richness, diversity, and composition of grasshoppers did not vary in regular fashion with the four-year fire cycle. Furthermore, the ratio of grass- to forb-feeding grasshoppers generally did not change consistently during the fire cycle at individual sites, although for all sites combined, the relative abundance of grass feeders initially increased after a fire and subsequently declined in succeeding years without fire. Observed year to year changes in grasshopper communities were tested against those predicted by a random walk model of community change using ordination (DCA) results for species composition at individual sites in individual years. This analysis revealed that local communities varied in restricted, compensatory fashion such that they tended to return towards some central or characteristic species composition when displaced. Thus while fire itself imparts relatively little predictability to grasshopper community dynamics in periodically unburned prairie, such dynamics are nevertheless to a limited degree predictable

}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.2307/3565201}, author = {Evans, E.W.} } @phdthesis {KNZ00200, title = {Comparative learning abilities and foraging strategies of Dipodomys merriami and Chaetodipus intermedius}, volume = {PhD Dissertation}, year = {1988}, pages = {1 -124}, school = {Kansas State University}, type = {Ph.D. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ}, author = {Rebar, C.E.} } @mastersthesis {KNZ00170, title = {Computer modeling of water yield from Kings Creek watershed}, volume = {MS Thesis}, year = {1988}, pages = {1 -95}, school = {Kansas State University}, type = {M.S. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ}, url = {http://krex.k-state.edu/dspace/handle/2097/36137}, author = {Bartlett, C.A.} } @inbook {KNZ00195, title = {Considerations in modeling the hydrology of Konza Prairie long-term ecological research site}, booktitle = {Modeling Agricultural, Forest and Rangeland Hydrology}, year = {1988}, pages = {377 -386}, publisher = {American Society of Agricultural Engineers}, organization = {American Society of Agricultural Engineers}, address = {St.Joseph, MI}, abstract = {

Participation by hydrologists in this project were merely in an advisory capacity until 1985. Since that time, participation has been limited to about 0.4 scientist-year per year and much of that time has been spent in design of measurement and sampling systems, calibration of flumes, and data reduction and interpretation. A recently completed MS thesis \"Computer Modeling of Water Yield from Kings Creek Watershed\" (Bartlett, 1988) represents the first attempt to model the hydrology of KPRNA. The results of parts of that work are summarized herein. The objectives were to (1) build a model specifically designed for the Kings Creek watershed; (2) to develop a climatological data set to calibrate this model; (3) to predict the runoff and percolation volumes for the subplots of the watershed; (4) to predict the streamflow in Kings Creek; and (5) to predict the long-term water yield for the watershed

}, keywords = {LTER-KNZ}, author = {Koelliker, J.K.} } @article {KNZ00142, title = {Canopy rainfall interception and throughfall in burned and unburned tallgrass prairie}, journal = {The Southwestern Naturalist}, volume = {32}, year = {1987}, pages = {267 -271}, abstract = {

Interception of precipitation by grass canopies in annually burned and unburned tallgrass prairie was measured for individual precipitation events from 1983 to 1984. Seasonal patterns of interception closely reflected differences in grass canopy development throughout the growing season in burned but not unburned prairie. Mean interception for the study period was 38 and 19\% for unburned and burned prairie, respectively, indicating tht througfall volume in burned prairie was approximately 1.3 times that of unburned prairie on an annual basis. Thus, water availability for plant uptake may be initally higher in burned prairie, especially early in the growing season

}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.2307/3671570}, author = {Gilliam, F.S. and Seastedt, T.R. and Alan K. Knapp} } @article {KNZ00151, title = {Changes in soluble nutrients of prairie riparian vegetation during decomposition on a floodplain}, journal = {The American Midland Naturalist}, volume = {117}, year = {1987}, pages = {26 -34}, abstract = {

Measurements of concentration of Mg, K, Ca, Na, dissolved organic carbon (DOC) and total N were made of the soluble fraction of leaves decomposing on the floodplain of a prairie stream. Differences in the concentrations of these nutrients were dependent on the species of leaf material and location on the floodplain. Leaves placed in the grassland reach of the stream had lower concentrations of soluble nutrients than leaves placed in the gallery forest. Correlations between concentration of leachable nutrients and cumulative precipitation or DOC were both positive and negative. Species differed in rank order of the nutrient concentration in leachates of their leaves. Bluestem and sycamore leaf leachate concentrations were low, whereas hackberry, elm and bur oak leaf leachate concentrations were relatively high

}, keywords = {LTER-KNZ}, doi = {10.2307/2425704}, author = {McArthur, J.V. and Marzolf, G.R.} } @article {KNZ00141, title = {The chemistry of wet deposition for a tallgrass prairie ecosystem: inputs and interactions with plant canopies}, journal = {Biogeochemistry}, volume = {4}, year = {1987}, pages = {203 -217}, abstract = {

The chemistry and nutrient inputs of wet deposition, and the N chemistry of throughfall, were characterized for a tallgrass prairie in north-central Kansas. Dominant ions in wetfall were NH4+, Ca2+, H+, NO3-, and SO2-4; weighted mean pH was 4.79. Principal sources of ions appeared to be natural emissions and wind-blown soils. Concentrations of NO3--N, NH4+-N and organic N in wet deposition were 0.31, 0.30, and 0.17 mg/L, respectively, resulting in N inputs of 2.5, 2.5, and 1.4 kg*ha- 1*yr-1. Comparisons with bulk precipitation suggested that at least 50\% of atmospheric N inputs were from dry deposition. Concentrations of NO3--N, NH4+-N, and organic N in unburned prairie throughfall were 0.27, 0.28, and 1.28 mg/L, and in burned prairie throughfall were 0.33, 0.37, and 0.91 mg/L, respectively. The prairie canopy intercepted up to 48\% of incident precipitation. Lower inorganic N and higher organic N concentrations in throughfall relative to wet deposition probably resulted from leaf uptake of N and immobilization by microbes associated with the standing dead plant materials of the prairie canopy. The removal of these materials by fire is important in maintaining N availability for tallgrass prairie. Much of the N immobilization appeared to have been of N that was supplied to the prairie canopy by dry deposition

}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.1007/BF02187366}, author = {Gilliam, F.S.} } @mastersthesis {KNZ00138, title = {Comparative breeding strategies of two coexisting passerines: Bell{\textquoteright}s vireo (Vireo bellii) and Bewick{\textquoteright}s wren (Thyromanes bewickii)}, volume = {MS Thesis}, year = {1987}, pages = {1 -52}, school = {Kansas State University}, type = {M.S. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ}, url = {http://krex.k-state.edu/dspace/handle/2097/22339}, author = {Farley, G.H.} } @article {KNZ00129, title = {Comparison of mass loss, nutrients, and invertebrates associated with elm leaf litter decomposition in perennial and intermittent reaches of tallgrass prairie streams}, journal = {The Southwestern Naturalist}, volume = {31}, year = {1986}, pages = {511 -520}, abstract = {

Decay rates, nutrient content and invertebrates associated with American elm leaves were examined in an intermittent and a perennial stream draining adjacent tallgrass prairie watersheds (Konza Prairie, Kansas). Both streams were flowing in November 1981 when leaf packs were placed in the channel. Elm leaves decayed faster in the perennial stream than in either of two intermittent sites. Decay rates were not different between the two intermittent sites. There were no significant differences among sites in either nitrogen (N) or phosphorus (P) concentrations or carbon to nitrogen (C:N) ratios in elm leaves. N concentrations of the leaves increased during decomposition whereas P decreased in concentration for the first two months and then increased; C:N ratios in elm leaves decreased during decomposition. Initial leaching of leaves may provide a nutrient input into prairie streams; but decomposing leaf material may also act as a nutrient sink and compete with other ecosystem processes. Shredder insects were low in abundance or absent from leaf packs

}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.2307/3671705}, author = {Tate, C.M. and Gurtz, M.E.} } @article {KNZ0099, title = {Canopy interception of nitrogen in bulk precipitation by annually burned and unburned tallgrass prairie}, journal = {Oecologia}, volume = {66}, year = {1985}, pages = {88 -92}, abstract = {

Nitrogen content of bulk precipitation and throughfall (canopy leachates) was measured on annually burned and unburned tallgrass prairie during a 20 month period. Throughfall amounts averages 58\% of precipitation on unburned prairie while throughfall on annually burned sites averaged 76\% of precipitation inputs. Stemflow was measured in late summer and autumn. Volumes were correlated with stem density; maximum stemflow volumes measured in this study averaged about 50\% of throughfall volumes. Bulk precipitation averages 530, 456, and 420 micrograms/l of nitrate, ammonium and organic nitrogen, respectively. Throughfall on burned sites averaged 345, 344, and 980 micrograms/l of nitrate, ammonium and organic nitrogen, and throughfall on unburned sites averaged 258, 196, and 1701 micrograms/l of nitrate ammonium and organic nitrogen. Microbes on standing dead vegetation and litter of the unburned sites were estimated to remove more inorganic nitrogen from bulk precipitation than did foliage on burned sites. Only a portion of the inorganic nitrogen in bulk precipitation is immediately available for plant use, and this availability is influenced by the amount of detritus present on the prairie

}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.1007/BF00378557}, author = {Seastedt, T.R.} } @article {KNZ0097, title = {Chronic effects of a prescribed field application of a carbamate insecticide on bobwhites}, journal = {The World Pheasant Association}, volume = {10}, year = {1985}, pages = {47 -64}, abstract = {

As part of the registration process for agricultural pesticides in the United States, Short-Term Field Tests for Hazard to Birds (small pen studies) are sometimes required for pesticides exhibiting moderate acute toxicity (Environmental Protection Agency 1978). We conducted such a small pen study to determine the chronic hazards of bendiocarb (an insecticide designed to control corn rootworms, trade name TATTOO, Fisons Ltd., Essex, England) to birds. Bendiocarb is a moderately toxic N-methyl N-dimethyl compound typical of the carbamate group of insecticides introduced into the United States in the mid-1950s. The small pen study was conducted with Northern Bobwhites (Colinus virginianus) under normal agricultural conditions. The scope of the study was expanded to include fatty acid analysis of eggs and body tissues of experimental birds, determination of energy content of eggs, quantitative measures of bobwhite mobility and activity, and analysis of brain cholinesterase activity. Major modifications of any of these parameters could pose adverse ecological problems for wild avian populations. This report presents the results of this small pen study and is contribution No. 85-347-J, Division of Biology, Kansas Agricultural Experiment Station, Kansas State University, Manhattan, KS 66502

}, keywords = {LTER-KNZ}, author = {Robel, R.J. and Arruda, S.M. and Morrow, M.E. and O{\textquoteright}Neill, D.H.} } @article {KNZ0069, title = {Central place foraging for non-food items: determination of the stick size value relationship of house building materials collected by eastern woodrats}, journal = {The American Naturalist}, volume = {123}, year = {1984}, pages = {841 -853}, abstract = {

Eastern woodrats (Nemotoma floridana) are medium-sized, nocturnal rodents that collect sticks and other objects as house building materials. A house is inhabited by one woodrat at a time, and provides many benefits to the occupant including protection from predators, protection from the weather, and a safe food storage site. Woodrats range from their houses to retrieve sticks and thus offer the opportunity to examine central place foraging for nonfood items. This paper examines procedures for determining the stick size-value relationship for woodrats initiating house building

}, keywords = {LTER-KNZ, forage, nest}, doi = {http://www.jstor.org/stable/2460904}, author = {McGinley, M.A.} } @article {KNZ0049, title = {Comparison of the diets of a caching and a noncaching rodent}, journal = {The American Naturalist}, volume = {122}, year = {1983}, pages = {576 -581}, abstract = {

We hypothesized that species which regularly cache food should have more diverse diets while feeding on their stores than species which have not evolved general caching behaviors. Such a diet by caching species would tend to reduce the probability of being left with only poor dietary items late in the period of cache use. To test this hypothesis, we designed an experiment to compare the diets of caching and noncaching species following a period of experimental feeding trials which simulated a caching situation

}, keywords = {LTER-KNZ, diet, rodent}, url = {https://www.jstor.org/stable/2461210}, author = {Reichman, O.J. and Fay, P.A.} } @article {KNZ0052, title = {Cowbird parasitism of dickcissels in different habitats and at different nest densities}, journal = {The Wilson Bulletin}, volume = {95}, year = {1983}, pages = {7 -22}, abstract = {

The purposes of this paper are 1) to determine the severity of the impact of the high frequency of cowbird nest parasitism on Dickcissel productivity, 2) analyze the incidence and intensity of parasitism as a function of habitat and the density of host nests, and 3) to assess the productivity of cowbirds in Dickcissel nests

}, keywords = {LTER-KNZ, habitat}, doi = {http://www.jstor.org/stable/4161714}, author = {Zimmerman, J.L.} } @article {KNZ0033, title = {Chemical changes in tree leaves during decomposition in a tallgrass prairie stream}, journal = {Ecology}, volume = {63}, year = {1982}, pages = {585 -589}, abstract = {

As part of an investigation into the movement patterns of elements in a prairie watershed, we performed preliminary leaf pack experiments in which the concentrations of 10 elements were measured in undecomposed gallery forest litterfall, and in the same litterfall as it decomposed in the adjacent tallgrass prairie stream. What we report here are the patterns of concentration change in these 10 elements for three dominant gallery forest tree species during 16 weeks of in-stream decomposition

}, keywords = {LTER-KNZ, decomposition, leaf, prairie, stream, tallgrass}, doi = {10.2307/1938976}, author = {Killingbeck, K.T. and Smith, D.L. and Marzolf, G.R.} } @proceedings {KNZ0023, title = {Controlling experimental bluestem prairie fires}, year = {1978}, pages = {169 -171}, publisher = {Iowa State University}, address = {Ames, IA}, abstract = {

Procedures are described that have been developed for experimental burning of 10 to 20 ha watersheds on Konza Prairie Research Natural Area in bluestem prairie near Manhattan, Kansas. First the fuel supply is reduced by July mowing and haying. In the autumn or spring fire guards about one meter wide are burned around the boundary of each watershed by burning between strips of metal edged with a band of chains which are pulled behind a tractor. Fire swatters and power water pumps are used to extinguish any fire that is left as the metal strips pass. At the time of the main burn two crews proceed in opposite directions from the middle of the leeward side. The fire is started next to the fire guard, with the crews ready in case the fire escapes. By the time the fire is started on the windward side, the fire has burned some distance back from the fire guard on the leeward side. The system works well in reasonable weather conditions

}, keywords = {LTER-KNZ, bluestem, fire, prairie}, author = {Hulbert, L.C.}, editor = {Glenn-Lewin, D.C. and Landers, R.Q.} }