@article {6361, title = {Heterogeneity promotes resilience in restored prairie: Implications for the environmental heterogeneity hypothesis}, journal = {Ecological Applications}, volume = {34}, year = {2024}, pages = {e3006}, keywords = {LTER-KNZ}, doi = {10.1002/eap.3006}, url = {https://esajournals.onlinelibrary.wiley.com/doi/10.1002/eap.3006}, author = {Wojciechowski, Ashley A. and J. M. Blair and S. Collins and S.G. Baer} } @mastersthesis {6279, title = {Are we there yet: Assessing trajectories of two restored prairies to target native prairies over a decadal time frame}, volume = {MS Thesis}, year = {2023}, school = {University of Kansas}, type = {M.S. Thesis}, address = {Lawrence, KS}, keywords = {LTER-KNZ}, author = {Weickert, Nathaniel} } @article {6172, title = {Persistent decadal differences in plant communities assembled under contrasting climate conditions}, journal = {Ecological Applications}, volume = {33}, year = {2023}, pages = {e2823}, keywords = {LTER-KNZ}, doi = {10.1002/eap.2823}, url = {https://onlinelibrary.wiley.com/doi/10.1002/eap.2823}, author = {Eckhoff, Kathryn D. and Scott, Drew A. and Manning, George and S.G. Baer} } @phdthesis {6137, title = {The effects of drought on plant and soil microbial communities and functioning during tallgrass prairie restoration}, volume = {PhD Dissertation}, year = {2022}, school = {University of Kansas}, type = {Ph.D. Thesis}, address = {Lawrence, KS}, keywords = {LTER-KNZ}, author = {Eckhoff, K.D.} } @article {5971, title = {Reciprocal transplant gardens as gold standard to detect local adaptation in grassland species: New opportunities moving into the 21st century}, journal = {Journal of Ecology}, volume = {110}, year = {2022}, pages = {1054-1071}, keywords = {LTER-KNZ}, doi = {10.1111/1365-2745.13695}, url = {https://onlinelibrary.wiley.com/doi/10.1111/1365-2745.13695}, author = {Johnson, Loretta C. and Galliart, Matthew B. and Alsdurf, Jacob D. and Maricle, Brian R. and S.G. Baer and Bello, Nora M. and Gibson, David J. and Smith, A.B.} } @article {5968, title = {Determinants of community compositional change are equally affected by global change}, journal = {Ecology Letters}, volume = {24}, year = {2021}, pages = {1892-1904}, abstract = {

Global change is impacting plant community composition, but the mechanisms underlying these changes are unclear. Using a dataset of 58 global change experiments, we tested the five fundamental mechanisms of community change: changes in evenness and richness, reordering, species gains and losses. We found 71\% of communities were impacted by global change treatments, and 88\% of communities that were exposed to two or more global change drivers were impacted. Further, all mechanisms of change were equally likely to be affected by global change treatments\—species losses and changes in richness were just as common as species gains and reordering. We also found no evidence of a progression of community changes, for example, reordering and changes in evenness did not precede species gains and losses. We demonstrate that all processes underlying plant community composition changes are equally affected by treatments and often occur simultaneously, necessitating a wholistic approach to quantifying community changes.

}, keywords = {LTER-KNZ}, doi = {10.1111/ele.13824}, url = {https://onlinelibrary.wiley.com/doi/10.1111/ele.13824}, author = {M.L. Avolio and Kimberly J. Komatsu and S.L Collins and Grman, Emily and Koerner, S.E. and Tredennick, A.T. and Wilcox, K.R. and Baer, S.G. and E.H. Boughton and Britton, Andrea J. and Foster, Bryan and Gough, Laura and Hovenden, Mark and Isbell, Forest and Jentsch, Anke and Johnson, David S. and Knapp, Alan K. and Kreyling, Juergen and Langley, J. Adam and Lortie, Christopher and McCulley, Rebecca L. and McLaren, Jennie R. and Reich, Peter B. and Seabloom, Eric W. and Smith, Melinda D. and Suding, Katharine N. and Suttle, K. Blake and Tognetti, Pedro M.}, editor = {Anderson, Marti} } @article {KNZ002045, title = {Mechanisms influencing physically sequestered soil carbon in temperate restored grasslands in South Africa and North America}, journal = {Biogeochemistry}, year = {2021}, abstract = {

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

}, keywords = {LTER-KNZ}, doi = {10.1007/s10533-021-00774-y}, url = {https://link.springer.com/article/10.1007/s10533-021-00774-y}, author = {Scott, D.A. and Bach, Elizabeth M. and Du Preez, Chris C. and Six, Johan and Baer, S.G.} } @article {5981, title = {Patterns and trends of organic matter processing and transport: Insights from the US Long-Term Ecological Research network}, journal = {Climate Change Ecology}, volume = {2}, year = {2021}, pages = {100025}, keywords = {LTER-KNZ}, doi = {10.1016/j.ecochg.2021.100025}, url = {https://linkinghub.elsevier.com/retrieve/pii/S2666900521000253}, author = {Harms, Tamara K. and Groffman, Peter M. and Aluwihare, Lihini and Craft, Chris and Wieder, William R and Hobbie, Sarah E. and S.G. Baer and J. M. Blair and Frey, Serita and Remucal, Christina K. and Rudgers, Jennifer A. and S L Collins} } @article {KNZ002060, title = {SoDaH: the SOils DAta Harmonization database, an open-source synthesis of soil data from research networks, version 1.0}, journal = {Earth System Science Data}, volume = {13}, year = {2021}, pages = {1843 - 1854}, keywords = {LTER-KNZ}, doi = {10.5194/essd-13-1843-2021}, url = {https://essd.copernicus.org/articles/13/1843/2021/essd-13-1843-2021.pdf}, author = {Wieder, William R. and Pierson, Derek and Earl, Stevan and Lajtha, Kate and S.G. Baer and Ballantyne, Ford and Berhe, Asmeret Asefaw and Billings, Sharon A. and Brigham, Laurel M. and Chacon, Stephany S. and Fraterrigo, Jennifer and Frey, Serita D. and Georgiou, Katerina and de Graaff, Marie-Anne and Grandy, A. Stuart and Hartman, Melannie D. and Hobbie, Sarah E. and Johnson, Chris and Kaye, Jason and Kyker-Snowman, Emily and Litvak, Marcy E. and Mack, Michelle C. and Malhotra, Avni and Moore, Jessica A. M. and Nadelhoffer, Knute and Rasmussen, Craig and Silver, Whendee L. and Sulman, Benjamin N. and Walker, Xanthe and Weintraub, Samantha} } @article {5992, title = {State changes: insights from the U.S. Long Term Ecological Research Network}, journal = {Ecosphere}, volume = {12}, year = {2021}, month = {e03433}, keywords = {LTER-KNZ}, doi = {10.1002/ecs2.v12.510.1002/ecs2.3433}, url = {https://onlinelibrary.wiley.com/toc/21508925/12/5}, author = {Zinnert, Julie C. and Nippert, J.B. and Rudgers, Jennifer A. and Pennings, Steven C. and Gonz{\'a}lez, Grizelle and Alber, Merryl and S.G. Baer and J. M. Blair and Burd, Adrian and S L Collins and Craft, Christopher and Di Iorio, Daniela and Dodds, Walter K. and Groffman, Peter M. and Herbert, Ellen and Hladik, Christine and Li, Fan and Litvak, Marcy E. and Newsome, Seth and O{\textquoteright}Donnell, John and Pockman, William T. and Schalles, John and Young, Donald R.} } @article {6296, title = {No difference in herbivory preferences among ecotypes of big bluestem (Andropogon gerardii)}, journal = {Transactions of the Kansas Academy of Science}, volume = {123}, year = {2020}, pages = {151}, keywords = {LTER-KNZ}, doi = {10.1660/062.123.0112}, url = {https://bioone.org/journals/transactions-of-the-kansas-academy-of-science/volume-123/issue-1-2/062.123.0112/No-Difference-in-Herbivory-Preferences-Among-Ecotypes-of-Big-Bluestem/10.1660/062.123.0112.full}, author = {Pittenger, Madison S. and Maricle, Keri L. and S.G. Baer and Johnson, Loretta C. and Maricle, Brian R.} } @article {KNZ002010, title = {Soil heterogeneity increases plant diversity after twenty years of manipulation during grassland restoration}, journal = {Ecological Applications}, volume = {30}, year = {2020}, pages = {e02014}, abstract = {

The \“environmental heterogeneity hypothesis\” predicts that variability in resources promotes species coexistence, but few experiments support this hypothesis in plant communities. A previous 15-yr test of this hypothesis in a prairie restoration experiment demonstrated a weak effect of manipulated soil resource heterogeneity on plant diversity. This response was attributed to a transient increase in richness following a post-restoration supplemental propagule addition, occasionally higher diversity under nutrient enrichment, and reduced cover of a dominant species in a subset of soil treatments. Here, we report community dynamics under continuous propagule addition in the same experiment, corresponding to 16\–20 yr of restoration, in response to altered availability and heterogeneity of soil resources. We also quantified traits of newly added species to determine if heterogeneity increases the amount and variety of niches available for new species to exploit. The heterogeneous treatment contained a factorial combination of altered nutrient availability and soil depth; control plots had no manipulations. Total diversity and richness were higher in the heterogeneous treatment during this 5-yr study due to higher cover, diversity, and richness of previously established forbs, particularly in the N-enriched subplots. All new species added to the experiment exhibited unique trait spaces, but there was no evidence that heterogeneous plots contained a greater variety of new species representing a wider range of trait spaces relative to the control treatment. The richness and cover of new species was higher in N-enriched soil, but the magnitude of this response was small. Communities assembling under long-term N addition were dominated by different species among subplots receiving added N, leading to greater dispersion of communities among the heterogeneous relative to control plots. Contrary to the deterministic mechanism by which heterogeneity was expected to increase diversity (greater variability in resources for new species to exploit), higher diversity in the heterogeneous plots resulted from destabilization of formerly grass-dominated communities in N-enriched subplots. While we do not advocate increasing available soil N at large scales, we conclude that the positive effect of environmental heterogeneity on diversity can take decades to materialize and depend on development of stochastic processes in communities with strong establishment limitation.

}, keywords = {LTER-KNZ}, author = {S.G. Baer and T. Adams and Scott, D.A. and John M. Blair and Scott. L. Collins} } @article {KNZ002036, title = {Temporal variability in production is not consistently affected by global change drivers across herbaceous-dominated ecosystems}, journal = {Oecologia}, volume = {194}, year = {2020}, pages = {735{\textendash}744}, keywords = {LTER-KNZ}, author = {Avolio, M.L. and Wilcox, K.R. and La Pierre, K.J. and Lemoine, N. and Bowman, W.D. and Collins, S.L. and Knapp, A.K. and Koerner, S.E. and Smith, M.D. and Baer, S.G. and Gross, K.L. and Isbell, F. and McLaren, J. and Reich, P.B. and Suding, K.N. and Suttle, K.B. and Tilman, D. and Xu, Z. and Yu, Q.} } @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 {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 {KNZ001877, title = {Diversity patterns from sequentially restored grasslands support the {\textquoteleft}environmental heterogeneity hypothesis{\textquoteright}}, journal = {Oikos}, volume = {128}, year = {2019}, pages = {1116 - 1122}, abstract = {

The \‘environmental heterogeneity hypothesis\’ (EHH) has been proposed as a mechanism that enables species coexistence through resource partitioning. In accordance with this hypothesis, plant diversity is predicted to increase with variability in resources, but there has been weak support for this hypothesis from experimental studies. The objectives of this research were to 1) characterize how resource availability and heterogeneity (coefficient of variation) change as plant communities develop using sequentially restored grasslands, 2) determine if resource heterogeneity relates to plant diversity (effective number of species, richness, and evenness), and 3) reveal if the strength of resource heterogeneity\–diversity relationships is different among levels of resource availability. We quantified means and coefficients of variation in soil nitrate and light availability in grasslands established on former agricultural lands for different times and their relationship to plant diversity using a geostatistically-informed design. Nitrate availability decreased exponentially with restoration age, but no directional change in nitrate heterogeneity across the chronosequence occurred due to high resource variability in some restorations. Light availability also decreased exponentially across the chronosequence, but there was no directional change in light heterogeneity. Nitrate heterogeneity was positively correlated with both plant richness and plant effective number of species at high levels of nitrate availability. However, no nitrate heterogeneity correlation was detected at low levels of nitrate availability. Light heterogeneity was positively correlated with plant effective number of species at low levels of light availability. However, no light heterogeneity correlation was detected at high levels of light availability. Plant evenness was not correlated with resource heterogeneity at any resource availability level. These results support the positive heterogeneity\–diversity relationship predicted by EHH, and uniquely that this relationship develops within a decade of plant community development, but can be obscured by resource availability.

}, keywords = {LTER-KNZ}, doi = {10.1111/oik.05877}, url = {http://doi.wiley.com/10.1111/oik.05877}, author = {Scott, D.A. and S.G. Baer} } @phdthesis {KNZ001959, title = {Environmental heterogeneity effects on diversity and nitrous oxide emissions from soil in restored prairie}, volume = {PhD Dissertation}, year = {2019}, school = {Southern Illinois University Carbondale }, type = {Ph.D. Thesis}, address = {Carbondale, IL}, keywords = {LTER-KNZ}, url = {https://opensiuc.lib.siu.edu/dissertations/1683/}, author = {Scott, Drew} } @article {KNZ001965, title = {Global change effects on plant communities are magnified by time and the number of global change factors imposed}, journal = {Proceedings of the National Academy of Sciences}, volume = {116}, year = {2019}, pages = {17867-17873}, abstract = {

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

}, keywords = {LTER-KNZ}, doi = {10.1073/pnas.1819027116}, url = {https://www.pnas.org/content/early/2019/08/14/1819027116}, author = {Kimberly J. Komatsu and M.L. Avolio and Lemoine, Nathan P. and Isbell, Forest and Grman, Emily and Houseman, Gregory R. and Koerner, Sally E. and Johnson, D.S. and K.R. Wilcox and Juha M. Alatalo and Anderson, J.P. and Aerts, R. and S.G. Baer and Baldwin, Andrew H. and Bates, J. and Beierkuhnlein, C. and Belote, R.T. and John M. Blair and Bloor, J.M.G. and Bohlen, P.J. and Edward W. Bork and Elizabeth H. Boughton and W.D. Bowman and Britton, Andrea J. and Cahill, James F. and Chaneton, Enrique J. and Chiariello, N.R. and Cheng, Jimin. and Scott. L. Collins and Cornelissen, J.H.C. and G. Du and Eskelinen, Anu and Firn, Jennifer and Foster, B. and Gough, L. and Gross, K. and Hallett, L.M. and Han, X. and Harmens, H. and Hovenden, M.J. and Jagerbrand, A. and Jentsch, A. and Kern, Christel and Klanderud, Kari and Alan K. Knapp and Kreyling, Juergen and Li, W. and Luo, Yiqi and McCulley, R.L. and McLaren, Jennie R. and Megonigal, Patrick and J.W. Morgan and Onipchenko, Vladimir and Pennings, S.C. and Prev{\'e}y, J.S. and Price, Jodi N. and P.B. Reich and Robinson, Clare H. and Russell, L.F. and Sala, O.E. and Seabloom, E.W. and M.D. Smith and Soudzilovskaia, Nadejda A. and Souza, Lara and K.N. Suding and Suttle, B.K. and Svejcar, T. and Tilman, David and Tognetti, P. and Turkington, R. and White, S. and Xu, Zhuwen and Yahdjian, L. and Yu, Q. and Zhang, Pengfei and Zhang, Yunhai} } @article {KNZ001972, title = {Local adaptation, genetic divergence, and experimental selection in a foundation grass across the US Great Plains{\textquoteright} climate gradient}, journal = {Global Change Biology}, volume = {25}, year = {2019}, pages = {850 - 868}, abstract = {

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

}, keywords = {LTER-KNZ}, doi = {10.1111/gcb.14534}, url = {http://doi.wiley.com/10.1111/gcb.14534}, author = {Galliart, Matthew and Bello, Nora and Knapp, Mary and Poland, Jesse and St Amand, Paul and S.G. Baer and Maricle, Brian and Smith, Adam B. and Johnson, Loretta} } @article {KNZ001910, title = {Restoring grassland in the context of climate change}, journal = {Grasslands and Climate Change}, year = {2019}, pages = {310 -322}, keywords = {LTER-KNZ}, doi = {10.1017/9781108163941.020}, url = {https://doi.org/10.1017/9781108163941.020}, author = {S.G. Baer and D.J. Gibson and Johnson, L.C.}, editor = {D.J. Gibson and Newman, J.A.} } @article {KNZ001890, title = {Advancing theories of ecosystem development through Long-Term Ecological Research}, journal = {BioScience}, volume = {68}, year = {2018}, pages = {554{\textendash}562}, abstract = {

Decades of place-based, long-term ecological research have generated important insights into patterns and processes among ecosystems. Here, we extend a theoretical framework based on Odum\&$\#$39;s \“strategy of ecosystem development\”\—which predicted distinct attributes of developing and mature ecosystems\—in the context of more recent theoretical advancements that predict how long-term changes in the presses (long-term, gradual changes) and pulses (abrupt changes) of drivers that regulate ecosystem functions (press\–pulse regimes) can influence their trajectories of development. Our modifications to ecosystem development theories (a) illustrate how press\–pulse regimes can cause ecosystems to continue to develop or oscillate around a stable state (pulsed stability) or cause them to decline if the press\–pulse regime changes faster than species and communities can adapt, (b) use examples from long-term ecological research of how attributes interact to affect development, and (c) suggest how revised and new theoretical frameworks can integrate long-term ecological research and observatory networks.

}, keywords = {LTER-KNZ}, doi = {10.1093/biosci/biy070}, url = {https://academic.oup.com/bioscience/advance-article-abstract/doi/10.1093/biosci/biy070/5051780?redirectedFrom=fulltext}, author = {Kominoski, J.S. and Gaiser, E.E. and S.G. Baer} } @article {KNZ001913, title = {Degraded soil increases the performance of a dominant grass, Andropogon gerardii (Big bluestem)}, journal = {Plant Ecology}, volume = {219}, year = {2018}, pages = {901 - 911}, abstract = {

Dominant grasses can suppress subordinate species in grassland restorations. Examining factors that influence performance of a dominant grass when interacting with subordinate forbs may provide insights for maintaining plant community diversity. The objective of our study was to determine how soils of different restoration ages and functionally different forbs influence the performance (using biomass and tillering rate as proxies) of a dominant grass: Andropogon gerardii. Sites included a cultivated field and two restored prairies (4 or 16 years after restoration) at Konza Prairie (NE Kansas). We hypothesized A. gerardii performance would be greater in more degraded soils and when interacting with legumes. Soil structure, nutrient status, and microbial biomass were measured in soil that was used to conduct the plant interaction study. Andropogon gerardii performance was measured during an 18-week greenhouse experiment using the relative yield index calculated from net absolute tillering rate and final biomass measurements in three soil restoration age treatments combined with four interacting forb treatments. Restoration improved soil structure, reduced plant-available nutrients, and increased microbial biomass. Relative yield index values of A. gerardii were greater with non-legumes than legumes. Andropogon gerardii performed best in degraded soils, which may explain the difficulty in restoring tallgrass prairie diversity in long-term cultivated soil. Results from this study suggest practices that promote soil aggregation and fungal biomass, coupled with including a high abundance of legumes in seed mixes could reduce dominance of A. gerardii and likely increase plant diversity in tallgrass prairie restorations.

}, keywords = {LTER-KNZ}, doi = {10.1007/s11258-018-0844-0}, url = {http://link.springer.com/10.1007/s11258-018-0844-0}, author = {Scott, Drew A. and S.G. Baer} } @article {KNZ001912, title = {Drought tolerance in ecotypes of big bluestem (Andropogon gerardii) relates to above-ground surface area: Results from a common garden experiment}, journal = {Flora}, volume = {246-247}, year = {2018}, pages = {52 - 60}, abstract = {

Big bluestem (Andropogon gerardii Vitman) is a dominant tallgrass species that has a wide range in North America with numerous genetically-distinct ecotypes, each adapted to conditions in their native habitat. In an evolutionary context, it was hypothesized that drought adaptation in A. gerardii would relate to plant surface area, where drought-adapted ecotypes were expected to be short with narrow leaves, thin stems, and few leaves per tiller. In the context of individual plants acclimating to reduced rainfall, rainout shelters were hypothesized to cause morphological reductions in surface area of individual plants. Morphological measurements were taken from four genetically-distinct ecotypes of A. gerardii across a precipitation gradient ranging from 500 to 900\ mm rain per year at three common garden sites in Colby, Hays, and Manhattan, Kansas, USA. Evolutionary responses to drier soils in A. gerardii resulted in reduction of evaporative surface area from leaves, as drought-adapted plants had fewer and smaller leaves. The most mesic ecotype of A. gerardii had the highest maximum leaf width, stem diameter, and leaf count across sites. There were few effects of environment on morphology in A. gerardii with reduced rainfall, however, indicating genetics plays a more prominent role than environment to influence morphology. We conclude that increased drought tolerance is related to an evolutionary reduction in evaporative surface area.

}, keywords = {LTER-KNZ}, doi = {10.1016/j.flora.2018.07.005}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0367253018302469}, author = {Kramer, Diedre L. and Maricle, Keri L. and Hilt, Christina J. and Martin, Nicole M. and Urban, Adam D. and Smart, Cera M. and S.G. Baer and Johnson, Loretta C. and Maricle, Brian R.} } @phdthesis {KNZ001915, title = {Environmental and biotic processes influencing floristic composition, quality, integrity, and function in tallgrass prairie assemblages}, volume = {PhD Dissertation}, year = {2018}, school = { Southern Illinois University}, type = {Ph.D. Thesis}, address = {Carbondale, IL}, keywords = {LTER-KNZ}, url = {https://opensiuc.lib.siu.edu/cgi/viewcontent.cgi?article=2597\&context=dissertations}, author = {Manning, G.} } @article {KNZ001911, title = {Genetic and environmental influences on stomates of big bluestem (Andropogon gerardii)}, journal = {Environmental and Experimental Botany}, volume = {155}, year = {2018}, pages = {477 - 487}, abstract = {

Big bluestem (Andropogon gerardii) is a dominant C4 prairie grass that has wide distribution and several genetically distinct ecotypes. Many of the ecotypic adaptations are related to water availability in the native environment. Stomates facilitate photosynthetic gas exchange and regulate water loss from the plant. As such, stomatal size and density represent possible adaptations to conserve water. We hypothesized drought-tolerant ecotypes of big bluestem would have fewer or smaller stomates compared to more mesic ecotypes. Five ecotypes of big bluestem were planted in four common gardens from western Kansas to southern Illinois, USA to determine genetic and environmental influences on stomates. Leaves of all ecotypes of A. gerardii were largely hypostomatous and genetics was a greater influence than environment for stomatal size and density. The drought-tolerant Sand bluestem had larger stomates on abaxial surfaces of leaves, but a lower density compared to most other ecotypes. The most mesic Illinois ecotype and the Kaw cultivar had the greatest density of stomates on abaxial surfaces of leaves. Sand Bluestem had a greater density of stomates on adaxial surfaces of leaves compared to all other ecotypes. Gas exchange measures followed patterns of stomate distribution, where abaxial CO2 uptake rates were greater than adaxial CO2 uptake rates, although differences between leaf surfaces was more pronounced in stomatal density than in CO2 uptake. There were minor differences in size and density of stomates among sites that corresponded with precipitation, although these differences were minor, illustrating the genetic underpinnings of stomates in big bluestem. There is a genetic predisposition for drought-tolerant ecotypes to have fewer stomates, illustrating an evolutionary adaptation to drought tolerance in an important prairie species.

}, keywords = {LTER-KNZ}, doi = {10.1016/j.envexpbot.2018.07.018}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0098847218300807}, author = {Varvel, Nick A. and Hilt, Christina J. and Johnson, Loretta C. and Galliart, Matthew and S.G. Baer and Maricle, Brian R.} } @article {KNZ001881, title = {Interannual variability in climate effects on community assembly and ecosystem functioning in restored prairie}, journal = {Ecosphere}, volume = {9}, year = {2018}, pages = {e02327}, abstract = {

Community assembly theory attempts to explain factors influencing the composition of communities, which can be governed by deterministic and/or stochastic processes. We used a sequential restoration approach to gain insights into how interannual variation in climate influences community assembly in an agriculture field restored to tallgrass prairie. Species composition and aboveground net primary production (ANPP) were followed for three years in each of three sequentially restored communities, which were established in different years, and sown with the same suite of species using the same live seeding rate for each species. There was a sequence-by-age interaction for sown, volunteer, and total species composition (P = 0.001), cover (P \< 0.009), diversity (P \< 0.024), and richness (P \< 0.025). Annual net primary production had a sequence-by-age interaction for total, sown, and volunteer species (P \< 0.05). In general, species diversity and richness increased over time. We attributed different starting compositions and trajectories in the developing composition of communities and ANPP among sequences to variation in precipitation. Sequences II and III were sown under drought conditions and became dominated by a drought-resistant agricultural weed that corresponded with delayed establishment and lower ANPP of sown species in those sequences. This study suggests that the effects of drought on community composition vary depending on restoration year, with younger restorations exhibiting greater sensitivity to drought than those that are more established.

}, keywords = {LTER-KNZ}, doi = {10.1002/ecs2.2327}, url = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1002/ecs2.2327}, author = {Manning, George C. and S.G. Baer} } @inbook {KNZ001855, title = {Soil ecosystem services: an overview}, booktitle = {Managing Soil Health for Sustainable Agriculture}, number = {1}, year = {2018}, pages = {17-38}, publisher = {Burleigh Dodds Science Publishing Limited}, organization = {Burleigh Dodds Science Publishing Limited}, address = {Cambridge}, keywords = {LTER-KNZ}, doi = {10.19103/AS.2017.0033.02}, author = {S.G. Baer and Birge, H.}, editor = {Reicosky, Don} } @phdthesis {KNZ001839, title = {Demographic responses of grassland songbirds to rangeland management in the tallgrass prairie}, volume = {PhD Dissertation}, year = {2017}, school = {Kansas State University}, type = {Ph.D. Thesis}, address = {Manhattan, KS.}, keywords = {LTER-KNZ}, url = {http://hdl.handle.net/2097/35800 }, author = {Verheijen, B.H.F.} } @article {KNZ001818, title = {Effects of grazing and fire frequency on floristic quality and its relationship to indicators of soil quality in tallgrass prairie}, journal = {Environmental Management}, volume = {60}, year = {2017}, pages = {1075}, chapter = {1062}, abstract = {

Fire and grazing are widely used to manage grasslands for conservation purposes, but few studies have evaluated the effects of these drivers on the conservation value of plant communities measured by the floristic quality index (FQI). Further, the influence of fire and grazing on soil properties and functions are difficult for land managers and restoration practitioners to assess. The objectives of this study were to: (1) quantify the independent and interactive effects of grazing and fire frequency on floristic quality in native tallgrass prairie to provide potential benchmarks for community assessment, and (2) to explore whether floristic quality can serve as an indicator of soil structure and function for more holistic ecosystem assessments. A factorial combination of fire frequencies (1\–2, 4, and 20 years return intervals) and grazing (by bison or ungrazed) treatments were sampled for plant species composition, and for several indicators of soil quality in lowland tallgrass prairie. Floristic quality, diversity, and richness were higher in grazed than ungrazed prairie over all fire frequencies (P\ \<\ 0.05). Available inorganic N, microbial biomass N, total N, and soil bulk density were also higher in grazed prairie soil over all fire frequencies (P\ \<\ 0.05). Microbial biomass C, total organic C, and total soil N were positively correlated with FQI (P\ \<\ 0.05). This study shows that floristic quality and soil N pools are more strongly influenced by grazing than fire and that floristic quality can be an indicator of total soil C and N stocks in never cultivated lowland prairie.

}, keywords = {LTER-KNZ, bison, grassland, Microbial biomass, nitrogen, restoration, Soil carbon}, doi = {10.1007/s00267-017-0942-0}, url = {https://www.ncbi.nlm.nih.gov/pubmed/28963572}, author = {Manning, G.C. and S.G. Baer and John M. Blair} } @article {KNZ001854, title = {Phenotypic distribution models corroborate species distribution models: A shift in the role and prevalence of a dominant prairie grass in response to climate change}, journal = {Global Change Biology}, volume = {23}, year = {2017}, pages = {4365{\textendash}4375}, abstract = {

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

}, keywords = {LTER-KNZ}, doi = {10.1111/gcb.13666}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.13666}, author = {Smith, A.B. and Alsdurf, J. and Knapp, M. and S.G. Baer and Johnson, L.C.} } @article {KNZ001797, title = {Recovery and relative influence of root, microbial, and structural properties of soil on physically sequestered carbon stocks in restored grassland}, journal = {Soil Science Society of America Journal}, volume = {81}, year = {2017}, pages = {50-60}, abstract = {

Managing soil to sequester C can help mitigate increasing CO2 in the atmosphere. To maximize this ecosystem service, more knowledge of factors influencing C sequestration is needed. The objectives of this study were to (i) quantify recovery of the roots, microbial biomass and composition, and soil structure across a chronosequence of grassland restorations and (ii) use a structural equation model to develop a data-based hypothesis on the relative influence of physical and biological soil properties on the soil C aggregate fraction diagnostic of sequestered C. Belowground plant biomass and tissue quality (C/N ratio), soil microbial biomass C, phospholipid fatty acid (PLFA) concentrations, soil structure, and soil C stocks in the bulk soil and each aggregate fraction were quantified from a cultivated field, prairies restored for 1 to 35-yr (n = 6), and a never-cultivated (native) prairie. Root biomass, microbial biomass C, arbuscular mycorrhizal fungi (AMF) PLFA biomass across the chronosequence increase to resemble native prairie following 35 yr of restoration. Many aspects of soil structure (i.e., bulk density, proportional mass of aggregate fractions, and aggregate mean weighted diameter) and the distribution C among soil fractions, including C in the micro-within-macro aggregate fraction (sequestered C), also became representative of native prairie within 35 yr of restoration. Total soil C stock and physically protected C increased at a similar rate (23 and 27 g C m-2 yr-1) respectively, across the chronosequence. After 35 yr of restoration, 50\% of the total C pool was physically protected. The structural equation modeling developed by these data hypothesizes that microbial biomass C and AMF biomass (microbial composition) have the strongest causal influence on physically protected C. This model needs to be tested using independent sites to achieve greater inference.

}, keywords = {LTER-KNZ}, doi = {10.2136/sssaj2016.05.0158}, url = {https://dl.sciencesocieties.org/publications/sssaj/abstracts/81/1/50}, author = {Scott, D.A. and S.G. Baer and John M. Blair} } @article {KNZ001819, title = {Restoration and management for plant diversity enhances the rate of belowground ecosystem recovery}, journal = {Ecological Applications}, volume = {27}, year = {2017}, pages = {355 - 362}, abstract = {

The positive relationship between plant diversity and ecosystem functioning has been criticized for its applicability at large scales and in less controlled environments that are relevant to land management. To inform this gap between ecological theory and application, we compared recovery rates of belowground properties using two chronosequences consisting of continuously cultivated and independently restored fields with contrasting diversity management strategies: grasslands restored with high plant richness and managed for diversity with frequent burning (n = 20) and grasslands restored with fewer species that were infrequently burned (n = 15). Restoration and management for plant diversity resulted in 250\% higher plant richness. Greater recovery of roots and more predictable recovery of the active microbial biomass across the high diversity management strategy chronosequence corresponded with faster recovery of soil structure. The high diversity grasslands also had greater nutrient conservation indicated by lower available inorganic nitrogen. Thus, mesic grasslands restored with more species and managed for high plant diversity with frequent burning enhances the rate of belowground ecosystem recovery from long-term disturbance at a scale relevant to conservation practices on the landscape

}, keywords = {LTER-KNZ, Aggregates, Biodiversity, carbon, Ecosystem function, nitrogen, phospholipid fatty acid, prairie, root, soil}, doi = {10.1002/eap.1503}, url = {https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/eap.1503}, author = {Klopf, Ryan P. and S.G. Baer and E.M. Bach and Six, Johan} } @mastersthesis {KNZ001914, title = {Restored prairie response to reduction in ectophagous insects}, volume = { MS Thesis}, year = {2017}, school = {Southern Illinois University}, type = {M.S. Thesis}, address = {Carbondale, IL}, keywords = {LTER-KNZ}, url = {https://opensiuc.lib.siu.edu/theses/2331/}, author = {Black, S.M.} } @mastersthesis {KNZ001816, title = {The role of soil heterogeneity in the recruitment of new species and interactions with grasshoppers (Acrididae) and Katydids (Tettigoniidae) in restored prairie}, volume = {MS Thesis}, year = {2017}, school = {Southern Illinois University}, type = {M.S. Thesis}, address = {Carbondale, IL}, keywords = {LTER-KNZ}, url = {https://opensiuc.lib.siu.edu/theses/2080/}, author = {T. Adams} } @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 {KNZ001743, title = {Environmental heterogeneity has a weak effect on diversity during community assembly in tallgrass prairie}, journal = {Ecological Monographs}, volume = {86}, year = {2016}, pages = {94 - 106}, abstract = {

Understanding what constrains the persistence of species in communities is at the heart of community assembly theory and its application to conserving and enhancing biodiversity. The \“environmental heterogeneity hypothesis\” predicts greater species coexistence in habitats with greater resource variability. In the context of community assembly, environmental heterogeneity may influence the variety and strength of abiotic conditions and competitive interactions (environmental filters) to affect the relative abundance of species and biodiversity. We manipulated key resources that influence plant diversity in tallgrass prairie (i.e., soil depth and nitrogen availability) to increase environmental heterogeneity prior to sowing native prairie species into a former agricultural field. We compared variability in nutrient availability, aboveground annual net primary productivity (ANPP), and the composition of species between replicate plots containing soil heterogeneity manipulations and plots with no resource manipulations (n = 4 per treatment) during the first 15 yr of community assembly as a test of the \“environmental heterogeneity hypothesis.\” The manipulations increased environmental heterogeneity, measured as the coefficient of variation in NO3-N availability and ANPP. Plant diversity, however, was similar and decayed exponentially and indiscriminately over time between the heterogeneity treatments. Species richness declined linearly over time in both heterogeneity treatments, but richness was higher in the more heterogeneous soil 2 yr following a second propagule addition 8 yr after the initial sowing. As a result, there was a lower rate of species loss over time in the more heterogeneous soil (0.60 species yr\−1) relative to the control soil (0.96 species yr\−1). Communities in each treatment exhibited strong convergence over time resulting from a shift in dominant species across all treatments and a gradual increase in the clonal C4 grass, Andropogon gerardii. We attribute the weak effect of heterogeneity on diversity to increasing dominance of a clonal species, which decreased the scale of soil treatments relative to plant size, dispersal limitation, and absence of a key driver (grazing) known to increase plant diversity under a frequent fire regime. Thus, steering community assembly to attain high biodiversity may depend more on manipulating processes that reduce dominance and facilitate the arrival of new species than promoting environmental heterogeneity.

}, keywords = {LTER-KNZ}, doi = {10.1890/15-0888.1}, url = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/15-0888.1}, author = {S.G. Baer and John M. Blair and Scott. L. Collins} } @mastersthesis {KNZ001785, title = {Recovery of whole soil conditions through restoration from agriculture and its role in mediating plant-plant competition}, volume = {MS Thesis}, year = {2015}, school = {Southern Illinois University Carbondale}, type = {M.S. Thesis}, address = {Carbondale, IL}, keywords = {LTER-KNZ}, url = {https://opensiuc.lib.siu.edu/theses/1826/}, author = {Scott, D.A.} } @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 {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 {KNZ001564, title = {Fitness among population sources of a dominant species (Andropogon gerardii Vitman) used in prairie restoration}, journal = {Torrey Botanical Society}, volume = {140}, year = {2014}, pages = {269 -279}, abstract = {

Planting native grasses can provide a source of seed for prairie restorations, but requires knowledge of how the plants that establish will perform. This study sought to determine variation in fitness of population sources of Andropogon gerardii, a dominant grassland species, when grown in a mesic common garden. Using multiple population sources, we tested the hypothesis that plants from populations within the local region would exhibit a \‘home-site advantage\’ as measured by higher fitness compared to plants from populations collected from drier regions of the tallgrass prairie ecosystem (up to 986 km west of the common garden). Plants collected from four pristine, never restored population sources from each of three regions (central Kansas, eastern Kansas, and southern Illinois) were raised in the greenhouse from seeds and planted in a common garden in Illinois. To estimate fitness, we used commonly measured traits related to seed production, including flowering tiller number and number of flowering raceme branches, seed number, viability, and percentage germination. There was no evidence of a \‘home-site advantage\’ for populations originating from southern Illinois. Rather, there was high within-region variability in fecundity. Plants from southern Illinois had the largest number of raceme branches per plant. Plants from eastern Kansas had the highest number of vegetative tillers per plant. Plants from central Kansas produced the most germinable seeds. Under the current climate, plants from any one of the three regions may be suitable to propagate seeds for restoration, but other traits may vary among populations to affect height, cover, and productivity.

}, keywords = {LTER-KNZ, Andropogon gerardii, fitness, grassland, reproductive effort, restoration}, doi = {10.3159/TORREY-D-12-00063.1}, url = {https://doi.org/10.3159/TORREY-D-12-00063.1}, author = {D.J. Gibson and Sendor, G. and Donatelli, J. and S.G. Baer and Johnson, L.} } @article {KNZ001611, title = {No effect of seed source on multiple aspects of ecosystem functioning during ecological restoration: cultivars compared to local ecotypes of dominant grasses}, journal = {Evolutionary Applications}, volume = {7}, year = {2014}, pages = {323 -335}, abstract = {

Genetic principles underlie recommendations to use local seed, but a paucity of information exists on the genetic distinction and ecological consequences of using different seed sources in restorations. We established a field experiment to test whether cultivars and local ecotypes of dominant prairie grasses were genetically distinct and differentially influenced ecosystem functioning. Whole plots were assigned to cultivar and local ecotype grass sources. Three subplots within each whole plot were seeded to unique pools of subordinate species. The cultivar of the increasingly dominant grass, Sorghastrum nutans, was genetically different than the local ecotype, but genetic diversity was similar between the two sources. There were no differences in aboveground net primary production, soil carbon accrual, and net nitrogen mineralization rate in soil between the grass sources. Comparable productivity of the grass sources among the species pools for four years shows functional equivalence in terms of biomass production. Subordinate species comprised over half the aboveground productivity, which may have diluted the potential for documented trait differences between the grass sources to influence ecosystem processes. Regionally developed cultivars may be a suitable alternative to local ecotypes for restoration in fragmented landscapes with limited gene flow between natural and restored prairie and negligible recruitment by seed.

}, keywords = {LTER-KNZ, genetic diversity, genetic structure, grassland, prairie, propagule, soil}, doi = {10.1111/eva.12124}, url = {https://onlinelibrary.wiley.com/doi/full/10.1111/eva.12124}, author = {S.G. Baer and D.J. Gibson and Benscoter, A.M. and Reed, L.K. and Campbell, R.E. and Klopf, R.P. and Willand, J.E. and Wodika, B.R.} } @mastersthesis {KNZ001648, title = {The role of deer browsing on plant community development and ecosystem functioning during tallgrass prairie restoration}, volume = {MS Thesis}, year = {2014}, school = {Southern Illinois University}, type = {M.S. Thesis}, address = {Carbondale, IL}, abstract = {

Tallgrass prairie in North America has been highly reduced and degraded by human activity (e.g. agriculture) and now human facilitated restoration is necessary to preserve and reestablish the biodiversity, structure and function of this system. In historical tallgrass prairie large ungulates (e.g. Bison bison) were keystone species that regulated many ecosystem properties and functions. Today, restored prairie often lacks these historical ungulates and white-tailed deer (Odocoileus virginianus) have largely assumed the role of dominant ungulates in small, tallgrass prairie restorations. Little is known about how white-tailed deer affect the development of plant communities and ecosystem function during the onset of prairie restoration. In June 2012 an agricultural field was restored to native prairie species in Konza Prairie Biological Station (KPBS) near Manhattan, KS. Immediately following seeding, experimental plots were established and fences were constructed in half of the plots to excluded white-tailed deer. From 2012 to 2013 deer browse of forbs, aboveground biomass (total, sown forbs, sown grasses, volunteer forbs and volunteer grasses), light availability at the soil surface, soil nutrients, and plant community composition were measure inside and outside of exclosures. The first year of this study occurred during a severe drought which diminished in year two, presenting the opportunity to examine the interaction of climate and deer browse on restoration. In plots where deer had access, the percentage of forbs browsed ranged from 1.3 to 10.5\%. The effect of deer browsing on aboveground biomass varied across years for each category of biomass. Total biomass appeared to be regulated more strongly by deer than climate, as unbrowsed plots produced similar biomass in each year despite major climatic variation, while browsed plots did not follow this trend. Across all sampling periods, deer browsing increased light availability by 20\%. In year two inorganic N was 19\% lower in browsed plots, though potential net N mineralization did not vary between treatments. Plant communities were significantly different between years and, between browsed and unbrowsed plots as time and browsing affected community composition, diversity and richness. Deer browsing increased diversity and richness by 24\% and 22\% respectively. Community composition was most greatly affected by browsing in year one corresponding to the highest rates of browsing and greatest differences in aboveground biomass. These results indicate that deer can have substantial effects on the initial establishment of prairie communities as well as resource availability from the onset of restoration.

}, keywords = {LTER-KNZ, Ecology; Conservation biology, Plant biology, range management}, url = {https://opensiuc.lib.siu.edu/theses/1515/}, author = {Harris, P.T.} } @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 {KNZ001563, title = {Environmental and genetic variation in leaf anatomy among populations of Andropogon gerardii (Poaceae) along a precipitation gradient}, journal = {American Journal of Botany}, volume = {100}, year = {2013}, pages = {1957 -1968}, abstract = {

\• Premise of the study: Phenotypes of two Andropogon gerardii subspecies, big bluestem and sand bluestem, vary throughout the prairie ecosystem of North America. This study sought to determine the role of genetics and environment in driving adaptive variation of leaf structure in big bluestem and sand bluestem. \• Methods: Four populations of big bluestem and one population of sand bluestem were planted in common gardens at four sites across a precipitation gradient from western Kansas to southern Illinois. Internal leaf structure and trichome density of A. gerardii were examined by light microscopy to separate genetic and environmentally controlled traits. Leaf thickness, midrib thickness, bulliform cells, interveinal distance, vein size, and trichome density were quantified. \• Key results: At all planting sites, sand bluestem and the xeric population of A. gerardii had thicker leaves and fewer bulliform cells compared with mesic populations. Environment and genetic source population were both influential for leaf anatomy. Leaves from plants grown in mesic sites (Carbondale, Illinois and Manhattan, Kansas) had thicker midribs, larger veins, fewer trichomes, and a greater proportion of bulliform cells compared to plants grown in drier sites (Colby and Hays, Kansas). \• Conclusions: Water availability has driven adaptive variation in leaf structure in populations of A. gerardii, particularly between sand bluestem and big bluestem. Genetically based differences in leaves of A. gerardii indicate adaptive variation and evolutionary forces differentiating sand bluestem from big bluestem. Environmental responses of A. gerardii leaves suggest an ability to adjust to drought, even in populations adapted to mesic home environments.

}, keywords = {LTER-KNZ, adaptive variatio, big bluestem, bulliform cells, drought adaptation, ecotypes, Kranz anatomy, leaf structure, n Andropogon gerardii, population, sand bluestem}, doi = {10.3732/ajb.1200628}, url = {https://bsapubs.onlinelibrary.wiley.com/doi/full/10.3732/ajb.1200628}, author = {Olsen, J.T. and Caudle, K.L. and Johnson, L.C. and S.G. Baer and Maricle, B.} } @article {KNZ001565, title = {Limited effects of dominant species population source on community composition during community assembly}, journal = {Journal of Vegetation Science}, volume = {24}, year = {2013}, pages = {429 -440}, abstract = {

Question To what extent do dominant species population sources and subordinate species pools affect diversity and composition of an assembling grassland community? Location Illinois, USA. Methods Percentage cover of all species were recorded annually in 36 1-m2 quadrats assigned to a factorial combination of dominant species population source (functionally distinct cultivar or non-cultivar seed source) and designed species pool (three levels varying in species identity, but with equal functional group representation and richness) during the first 4 yr of community assembly in an experimental grassland restoration. Results Univariate and multivariate analyses showed that individual species abundance, life form and community composition differed significantly among designed species pools, but were not strongly affected by population source of the dominant species (cultivar or non-cultivar). There were fewer C4 species in cultivar plots but only in one of three designed species pools during one of 4 yr of community assembly. The number of legume and forb species was higher in cultivar plots, but also only in one of the 4 yr of study. Other changes in species richness and abundance were solely related to successional change. Conclusions Non-dominant species introduced to restore plant communities strongly affects plant community composition, and composition can show fidelity to designed species pools. Only marginal or temporary effects of dominant species seed source were observed in the assembling plant community. Thus, we found no strong evidence that the source of dominant species, in this case cultivars compared to local ecotypes, has consequences for community assembly in the early stages of restoration (1\–4 yr). The absence of a strong dominant species source effect may be exacerbated by the assembly of diverse plant communities, resulting in a stronger effect of subordinate species seed mixture in restoration.

}, keywords = {LTER-KNZ, Community assembly, dominant species, Extended phenotype, grassland, restoration, Seed pool, tallgrass prairie}, doi = {10.1111/j.1654-1103.2012.01475.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1654-1103.2012.01475.x}, author = {D.J. Gibson and S.G. Baer and Klopf, R.P. and Reed, L.K. and Wodika, B.R. and Willand, J.E.} } @mastersthesis {KNZ001649, title = {Regional-climate and local-microbial controls on ecosystem processes during grassland restoration}, volume = {MS Thesis}, year = {2013}, school = {Southern Illinois University}, type = {M.S. Thesis}, address = {Carbondale, IL}, abstract = {

Root productivity likely has consequences for the composition, activity, and recovery of soil microbial populations and the belowground processes mediated by these organisms. In tallgrass prairie, ecotypic variation potentially exists in response to a strong precipitation gradient across the Great Plains. Thus, ecotypic variation within a species may differentially affect belowground net primary productivity (BNPP), the associated soil microbial community, and may scale up to affect ecosystem processes. The goals of this study were to elucidate: (1) whether ecotype, environment, or an ecotype by environment interaction regulate BNPP of a dominant species (Andropogon gerardii) collected from and reciprocally planted in common gardens across a precipitation gradient, and (2) whether variation in BNPP scales to affect microbial biomass and ecosystem processes. I quantified root biomass, BNPP (using root ingrowth bags), soil microbial biomass, and nutrient mineralization rates in root-ingrowth cores below six population sources of A. gerardii (2 Illinois, 2 eastern Kansas, and 2 central Kansas) established in southern Illinois, eastern Kansas, and central Kansas. An ecotype effect was found on above and belowground net primary productivity, but these findings did not translate to soil response variables. Microbial populations themselves may affect the productivity and composition of prairie species. In a second study, soil ecological knowledge (SEK) was tested by applying a native prairie soil slurry amendment to restoration plots to determine efficacy of this method as a restoration practice. The goals of this two year study were to elucidate: (1) whether a slurry amendment of prairie soil would increase above and belowground productivity and belowground ecosystem processes in a prairie restoration, and (2) to evaluate whether differences in plant diversity will scale to affect belowground productivity and ecosystem processes. I quantified aboveground net primary productivity (ANPP) and species composition, as well as root biomass, belowground net primary productivity (BNPP), soil microbial biomass, and nutrient mineralization rates in root-ingrowth cores installed in treated and control plots. A treatment effect was noted on root biomass and total PLFA biomass; however, there was no treatment effect on cover, ANPP, or soil microbial processes. Though the soil microbial community did represent native prairie soil, there was poor establishment of prairie plant species. These factors may be due to the limited time available for data collection and the lack of precipitation in the second growing season. Longer studies may be necessary to fully examine the effects of soil slurry amendments as restoration tools.

}, keywords = {LTER-KNZ}, url = {http://opensiuc.lib.siu.edu/theses/1338/}, author = {Mendola, M.M.} } @inbook {KNZ001655, title = {Restoration Ecology}, booktitle = {Oxford Bibliographies in Ecology}, year = {2013}, publisher = {Oxford University Press}, organization = {Oxford University Press}, address = {New York}, keywords = {LTER-KNZ}, url = {http://www.oxfordbibliographies.com}, author = {S.G. Baer}, editor = {D.J. Gibson} } @article {KNZ001562, title = {Temporal dynamics of plant community regeneration sources during tallgrass prairie restoration}, journal = {Plant Ecology}, volume = {214}, year = {2013}, pages = {1169 -1180}, abstract = {

Ecological restoration aims to augment and steer the composition and contribution of propagules for community regeneration in degraded environments. We quantified patterns in the abundance, richness, and diversity of seed and bud banks across an 11-year chronosequence of restored prairies and in prairie remnants to elucidate the degree to which the germinable seed bank, emerged seedlings, belowground buds, and emerged ramets were related to community regeneration. There were no directional patterns in the abundance, richness, or diversity of the germinable seed bank across the chronosequence. Emerged seedling abundance of sown species decreased during restoration. Richness and diversity of all emerged seedlings and non-sown emerged seedling species decreased across the chronosequence. Conversely, abundance and richness of belowground buds increased with restoration age and belowground bud diversity of sown species increased across the chronosequence. Numbers of emerged ramets also increased across the chronosequence and was driven primarily by the number of graminoid ramets. There were no temporal changes in abundance and richness of sown and non-sown emerged ramets, but diversity of sown emerged ramets increased across the chronosequence. This study demonstrates that after initial seeding, plant community structure in restored prairies increasingly reflects the composition of the bud bank.

}, keywords = {LTER-KNZ, chronosequence, Community assembly, diversity, Propagules, Species richness}, doi = {10.1007/s11258-013-0241-7}, url = {https://link.springer.com/article/10.1007\%2Fs11258-013-0241-7}, author = {Willand, J.E. and S.G. Baer and D.J. Gibson and Klopf, R.P.} } @inbook {KNZ001435, title = {Applying soil ecological knowledge to restore ecosystem services}, booktitle = {Soil Ecology and Ecosystem Services}, year = {2012}, pages = {377 -393}, publisher = {Oxford University Press}, organization = {Oxford University Press}, address = {Oxford, UK}, abstract = {Ecological restoration is human-facilitated improvement of a degraded environment. This chapter synthesizes the relevance of soil ecological knowledge to restoration along a continuum of ecosystem degradation and in the context of novel ecosystems. At one end of the continuum, mining can result in severe soil degradation and contamination with metals. Restoration of mined sites often focuses on decontamination, and success can be affected by soil heterogeneity, organic matter content, and refugia for soil biota that possess biodegradation pathways. Former agricultural sites can exhibit a wide range of soil and ecosystem legacies, with restoration goals ranging from simply reducing erosion with perennial plants to establishing a suite of historic ecosystem attributes and services through the re-introduction of many species. Although recovery of soil structure and function can coincide with plant establishment, knowledge of soil processes and plant{\textendash}soil feedbacks have been applied to promote resource heterogeneity and plant diversity, and to reduce non-native species in restored agricultural systems. Even in relatively undisturbed sites with high legacy of native plants and soil, invasions of undesirable species may occur. Restoration of invaded systems may necessitate knowledge of how invaders impact resource availability and capture, as well as potentially complex multi-trophic interactions and feedbacks with soil. Last, restoration of novel ecosystems with new and self-sustaining assemblages of plant species in no-analog environments may require sophisticated consideration of biogeochemistry, plant population and community dynamics, and soil ecology to reintroduce and sustain native species long extirpated from local environments.}, keywords = {LTER-KNZ, agriculture, Invasive species, mining; novel ecosystem, plant{\textendash}soil feedback, restoration, soil ecological knowledge}, doi = {10.1093/acprof:oso/9780199575923.003.0032}, url = {http://dx.doi.org/10.1093/acprof:oso/9780199575923.003.0032}, author = {S.G. Baer and Heneghan, L. and Eviner, V.}, editor = {Wall, D.} } @article {KNZ001436, title = {Effects of foundation species genotypic diversity on subordinate species richness in an assembling community}, journal = {Oikos}, volume = {121}, year = {2012}, pages = {496 -507}, abstract = {

Foundation (dominant or matrix) species play a key role in structuring plant communities, influencing processes from population to ecosystem scales. However, the effects of genotypic diversity of foundation species on these processes have not been thoroughly assessed in the context of assembling plant communities. We modified the classical filter model of community assembly to include genotypic diversity as part of the biotic filter. We hypothesized that the proportion of fit genotypes (i.e. competitively superior and dominant) affects niche space availability for subordinate species to establish with consequence for species diversity. To test this hypothesis, we used an individual-based simulation model where a foundation species of varying genotypic diversity (number of genotypes and variability among genotypes) competes for space with subordinate species on a spatially heterogeneous lattice. Our model addresses a real and practical problem in restoration ecology: choosing the level of genetic diversity of re-introduced foundation and subordinate species. Genotypic diversity of foundation species significantly affected equilibrium community diversity, measured as species richness, either positively or negatively, depending upon environmental heterogeneity. Increases in genotypic diversity gave the foundation species a wider niche breadth. Under conditions of high environmental heterogeneity, this wider niche breadth decreased niche space for other species, lowering species richness with increased genotypic diversity until the genotypes of the foundation species saturated the landscape. With a low level of environmental heterogeneity, increasing genotypic diversity caused the foundation species niche breadth to be overdispersed, resulting in a weak positive relationship with species richness. Under these conditions, some genotypes are maladapted to the environment lowering fitness of the foundation species. These effects of genotypic diversity were secondary to the larger effects of overall foundation species fitness and environmental heterogeneity. The novel aspect of incorporating genotype diversity in combination with environmental heterogeneity in community assembly models include predictions of either positive or negative relationships between species diversity and genotypic diversity depending on environmental heterogeneity, and the conditions under which these factors are potentially relevant. Mechanistically, differential niche availability is imposed by the foundation species.

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1600-0706.2011.19447.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1600-0706.2011.19447.x}, author = {D.J. Gibson and Alstadt, A.J. and S.G. Baer and Geisler, M.} } @article {KNZ001516, title = {Plant and soil responses to high and low diversity grassland restoration practices}, journal = {Environmental Management}, volume = {49}, year = {2012}, pages = {412 -424}, abstract = {

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

}, keywords = {LTER-KNZ, Conservation reserve program, Nitrogen mineralization, Phospholipid fatty acids, Soil microbial community, tallgrass prairie}, doi = {10.1007/s00267-011-9787-0}, url = {https://link.springer.com/article/10.1007\%2Fs00267-011-9787-0}, author = {E.M. Bach and S.G. Baer and Six, J.} } @mastersthesis {KNZ001517, title = {Response of regional sources of tallgrass prairie species to variation in climate and soil microbial communities}, volume = {MS Thesis}, year = {2012}, school = {Kansas State University}, type = {M.S. Thesis}, address = {Manhattan, KS}, abstract = {

Restoration of resilient plant communities in response to environmental degradation is a critical task, and a changing climate necessitates the introduction of plant communities adapted to anticipated future conditions. Ecotypes of dominant species can affect associated organisms as well as ecosystem function. The extent of ecotypic variation in dominant tallgrass prairie species and the consequences of this variation for ecosystem functioning were studied by manipulating two potential drivers of plant community dynamics: climate and the soil microbial community. Climate was manipulated indirectly through the use of reciprocal restorations across a rainfall gradient where regional sources of dominant grasses Andropogon gerardii and Sorghastrum nutans were seeded with 8 other native species that occur in tallgrass prairie. Four dominant grass sources (originating from central Kansas [CKS], eastern Kansas [EKS], southern Illinois [SIL], or a mixture of these) were reciprocally planted within four sites that occurred across a precipitation gradient in western KS (Colby, KS), CKS (Hays, KS), EKS (Manhattan, KS) and SIL (Carbondale, IL). The three grass sources and mixture of sources were sown into plots according to a randomized complete block design at each sites (n=16, 4 plots / block at each site). Aboveground net primary productivity (ANPP) was measured at the end of the 2010 and 2011 growing season at each site. In 2010, total ANPP declined from western to eastern Kansas, but increased across the geographic gradient in 2011. The dominant grasses did not comprise the majority of community ANPP in WKS, CKS or SIL in either year but did contribute most to total ANPP at the EKS site in 2011. In 2010, volunteer forbs comprised the largest proportion of ANPP in WKS, whereas and in both years planted forbs comprised the largest proportion of ANPP in SIL. Ecotypic variation in ANPP of A. gerardii was not evident, but Sorghastrum nutans ANPP exhibited a site by source effect in 2010 that did not suggest a home site advantage. Variation in the competitive environment at each site may have masked ecotypic variation during community assembly. Further, ANPP responses suggest that grasslands in early stages of establishment may respond more stochastically to climatic variation than established grasslands. Longer term studies will clarify whether ecotypes of dominant prairie grasses affect ecosystem function or community trajectories differently during restoration. Ecotypes of dominant species may support different soil microflora, potentially resulting in plant-soil feedback. A second experiment tested for local adaptation of prairie plant assemblages to their soil microbial community. Native plant assemblages from Kansas and Illinois were tested for local adaptation to their {\textquoteleft}home\&$\#$39; soil by reciprocally crossing soil and plant source in a greenhouse experiment. Seeds and soil were obtained from two remnant prairies, one in eastern Kansas and one in central Illinois, with similar species composition but differing climate. Seeds of four species (Andropogon gerardii, Elymus canadensis, Lespedeza capitata, Oligoneuron rigidum) common to both locations were collected, germinated, and transferred to pots to create 4-species assemblages from each region. Non-prairie (NP) soil from the edge of an Illinois agricultural field was also included as an inoculum treatment to increase relevance to restoration. Kansas and Illinois plant assemblages were subjected to a fully factorial combination of soil inocula [with associated microbial communities] (3 sources: KS, IL, NP) and soil sterilization treatment (sterilized or live). Plants were harvested after 20 weeks and soil was analyzed for microbial composition using phospholipid fatty acid (PLFA) markers. Soil sources had different nutrient concentrations and sterilization resulted in a flush of NH4+, which complicated detection of soil microbial effects. However, plant sources did exhibit variation in productivity responses to soil sources, with Kansas plants more responsive to live soil sources than Illinois plants. Despite confounding variation in soil fertility, soil inoculation was successful at manipulating soil microbial communities, and plant sources responded differently to soil sources. Consideration of feedback between soil and plants may be a missing link in steering restoration trajectories.

}, keywords = {LTER-KNZ}, url = {http://opensiuc.lib.siu.edu/theses/922/}, author = {Goad, R.K.} } @article {KNZ001310, title = {Intraspecific Variation in Ecophysiology of Three Dominant Prairie Grasses Used in Restoration: Cultivar Versus Non-Cultivar Population Sources}, journal = {Restoration Ecology}, volume = {19}, year = {2011}, pages = {43 -52}, abstract = {

Dominant species play crucial roles in determining plant community structure and ecosystem function. Cultivars of the dominant prairie grasses are widely used in prairie restoration and are selected for characters such as high biomass production, increased reproductive output, and stress tolerance. Genetic differences exist between cultivar and non-cultivar population sources of dominant tallgrass prairie species, which may have implications for plant performance in prairie restoration. We measured net photosynthesis (Anet), stomatal conductance (gs), and water use efficiency (WUE) in cultivar and non-cultivar dominant tallgrass prairie species Andropogon gerardii Vitman, Sorghastrum nutans (L.) Nash, and Schizachyrium scoparium (Michx.) Nash in both a greenhouse experiment and an experimental tallgrass prairie restoration. We found indicators of enhanced physiological performance (higher Anet, gs, and/or WUE) in cultivar population sources of all three dominant grass species relative to non-cultivars. For A. gerardii, cultivars exhibited higher Anet and WUE than non-cultivars. For S. nutans, cultivars exhibited higher gs, whereas non-cultivars showed higher WUE. Lastly, cultivars of S. scoparium showed higher WUE than non-cultivar population sources. Our results show that population selection of dominant species in restoration can have consequences for plant performance, which may have implications for competitive interactions that affect community structure (i.e. diversity) and ecosystem function (i.e. aboveground net primary production) during the reassembly of prairie systems.

}, keywords = {LTER-KNZ, Andropogon gerardii, Ecophysiology, photosynthesis, restoration, Schizachyrium scoparium, Sorghastrum nutans, tallgrass prairie}, doi = {10.1111/j.1526-100X.2010.00673.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1526-100X.2010.00673.x}, author = {Lambert, A.M. and S.G. Baer and D.J. Gibson} } @article {KNZ001311, title = {Root dynamics of cultivar and non-cultivar population sources of two dominant grasses during initial establishment of tallgrass prairie}, journal = {Restoration Ecology}, volume = {19}, year = {2011}, pages = {112 -117}, abstract = {

Dominance of warm-season grasses modulates tallgrass prairie ecosystem structure and function. Reintroduction of these grasses is a widespread practice to conserve soil and restore prairie ecosystems degraded from human land use changes. Seed sources for reintroduction of dominant prairie grass species include local (non-cultivar) and selected (cultivar) populations. The primary objective of this study was to quantify whether intraspecific variation in developing root systems exists between population sources (non-cultivar and cultivar) of two dominant grasses (Sorghastrum nutans and Schizachyrium scoparium) widely used in restoration. Non-cultivar and cultivar grass seedlings of both species were isolated in an experimental prairie restoration at the Konza Prairie Biological Station. We measured above- and belowground net primary production (ANPP and BNPP, respectively), root architecture, and root tissue quality, as well as soil moisture and plant available inorganic nitrogen (N) in soil associated with each species and source at the end of the first growing season. Cultivars had greater root length, surface area, and volume than non-cultivars. Available inorganic N and soil moisture were present in lower amounts in soil proximal to roots of cultivars than non-cultivars. Additionally, soil NO3\–N was negatively correlated with root volume in S. nutans cultivars. While cultivars had greater BNPP than non-cultivars, this was not reflected aboveground root structure, as ANPP was similar between cultivars and non-cultivars. Intraspecific variation in belowground root structure and function exists between cultivar and non-cultivar sources of the dominant prairie grasses during initial reestablishment of tallgrass prairie. Population source selection should be considered in setting restoration goals and objectives.

}, keywords = {LTER-KNZ, cultivar, dominant grasses, local ecotype, Roots, tallgrass prairie restoration}, doi = {10.1111/j.1526-100X.2009.00539.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1526-100X.2009.00539.x}, author = {Klopf, R.P. and S.G. Baer} } @article {KNZ001357, title = {Soil texture affects soil microbial and structural recovery during grassland restoration}, journal = {Soil Biology \& Biochemistry}, volume = {42}, year = {2011}, pages = {2182 -2191}, abstract = {

Many biotic and abiotic factors influence recovery of soil communities following prolonged disturbance. We investigated the role of soil texture in the recovery of soil microbial community structure and changes in microbial stress, as indexed by phospholipid fatty acid (PLFA) profiles, using two chronosequences of grasslands restored from 0 to 19 years on silty clay loam and loamy fine sand soils in Nebraska, USA. All restorations were formerly cultivated fields seeded to native warm-season grasses through the USDA\’s Conservation Reserve Program. Increases in many PLFA concentrations occurred across the silty clay loam chronosequence including total PLFA biomass, richness, fungi, arbuscular mycorrhizal fungi, Gram-positive bacteria, Gram-negative bacteria, and actinomycetes. Ratios of saturated:monounsaturated and iso:anteiso PLFAs decreased across the silty clay loam chronosequence indicating reduction in nutrient stress of the microbial community as grassland established. Multivariate analysis of entire PLFA profiles across the silty clay loam chronosequence showed recovery of microbial community structure on the trajectory toward native prairie. Conversely, no microbial groups exhibited a directional change across the loamy fine sand chronosequence. Changes in soil structure were also only observed across the silty clay loam chronosequence. Aggregate mean weighted diameter (MWD) exhibited an exponential rise to maximum resulting from an exponential rise to maximum in the proportion of large macroaggregates (\>2000 μm) and exponential decay in microaggregates (\<250 μm and \>53 μm) and the silt and clay fraction (\<53 μm). Across both chronosequences, MWD was highly correlated with total PLFA biomass and the biomass of many microbial groups. Strong correlations between many PLFA groups and the MWD of aggregates underscore the interdependence between the recovery of soil microbial communities and soil structure that may explain more variation than time for some soils (i.e., loamy fine sand). This study demonstrates that soil microbial responses to grassland restoration are modulated by soil texture with implications for estimating the true capacity of restoration efforts to rehabilitate ecosystem functions.

}, keywords = {LTER-KNZ, Aggregates, Conservation Reserve Program (CRP), Microbial biomass, Phospholipid fatty acids, Soil microbial communities, tallgrass prairie}, doi = {10.1016/j.soilbio.2010.08.014}, url = {https://www.sciencedirect.com/science/article/abs/pii/S0038071710003020?via\%3Dihub}, author = {E.M. Bach and S.G. Baer and Meyer, C.K. and Six, J.} } @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 {KNZ001285, title = {Dominant grasses suppress local diversity in restored tallgrass prairie}, journal = {Restoration Ecology}, volume = {18}, year = {2010}, pages = {40 -49}, abstract = {

Warm-season (C4) grasses commonly dominate tallgrass prairie restorations, often at the expense of subordinate grasses and forbs that contribute most to diversity in this ecosystem. To assess whether the cover and abundance of dominant grass species constrain plant diversity, we removed 0, 50, or 100\% of tillers of two dominant species (Andropogon gerardii or Panicum virgatum) in a 7-year-old prairie restoration. Removing 100\% of the most abundant species, A. gerardii, significantly increased light availability, forb productivity, forb cover, species richness, species evenness, and species diversity. Removal of a less abundant but very common species, P. virgatum, did not significantly affect resource availability or the local plant community. We observed no effect of removal treatments on critical belowground resources, including inorganic soil N or soil moisture. Species richness was inversely correlated with total grass productivity and percent grass cover and positively correlated with light availability at the soil surface. These relationships suggest that differential species richness among removal treatments resulted from treatment induced differences in aboveground resources rather than the belowground resources. Selective removal of the dominant species A. gerardii provided an opportunity for seeded forb species to become established leading to an increase in species richness and diversity. Therefore, management practices that target reductions in cover or biomass of the dominant species may enhance diversity in established and grass-dominated mesic grassland restorations.

}, keywords = {LTER-KNZ, Andropogon gerardii, Competition, diversity, mesic grassland restoration, Panicum virgatum, species removal}, doi = {10.1111/j.1526-100X.2010.00669.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1526-100X.2010.00669.x}, author = {McCain, K.N.S. and S.G. Baer and John M. Blair and G.T. Wilson} } @article {KNZ001220, title = {Non-target and invasive species in rehabilitated production systems: Ecological impacts, management and future use}, journal = {Environmental Management}, volume = {43}, year = {2009}, pages = {189 -196}, keywords = {LTER-KNZ}, author = {S.G. Baer and Engle, D. and Knops, J.M.H. and Langeland, K.A. and Maxwell, B.D. and Menalled, F.D. and Symstad, A.} } @article {KNZ001140, title = {Grassland establishment under varying resource availability: A test of positive and negative feedback}, journal = {Ecology}, volume = {89}, year = {2008}, pages = {1859 -1871}, abstract = {

The traditional logic of carbon (C) and nitrogen (N) interactions in ecosystems predicts further increases or decreases in productivity (positive feedback) in response to high and low fertility in the soil, respectively; but the potential for development of feedback in ecosystems recovering from disturbance is less well understood. Furthermore, this logic has been challenged in grassland ecosystems where frequent fires or grazing may reduce the contribution of aboveground litter inputs to soil organic matter pools and nutrient supply for plant growth, relative to forest ecosystems. Further, if increases in plant productivity increase soil C content more than soil N content, negative feedback may result from increased microbial demand for N making less available for plant growth. We used a field experiment to test for feedback in an establishing grassland by comparing aboveground net primary productivity (ANPP) and belowground pools and fluxes of C and N in soil with enriched, ambient, and reduced N availability. For eight years annual N enrichment increased ANPP, root N, and root tissue quality, but root C:N ratios remained well above the threshold for net mineralization of N. There was no evidence that N enrichment increased root biomass, soil C or N accrual rates, or storage of C in total, microbial, or mineralizable pools within this time frame. However, the net nitrogen mineralization potential (NMP) rate was greater following eight years of N enrichment, and we attributed this to N saturation of the microbial biomass. Grassland developing under experimentally imposed N limitation through C addition to the soil exhibited ANPP, root biomass and quality, and net NMP rate similar to the ambient soil. Similarity in productivity and roots in the reduced and ambient N treatments was attributed to the potentially high nitrogen-use efficiency (NUE) of the dominant C4 grasses, and increasing cover of legumes over time in the C-amended soil. Thus, in a developing ecosystem, positive feedback between soil N supply and plant productivity may promote enhanced long-term N availability and override progressive N limitation as C accrues in plant and soil pools. However, experimentally imposed reduction in N availability did not feed back to reduce ANPP, possibly due to shifts in NUE and functional group composition.

}, keywords = {LTER-KNZ}, doi = {10.1890/07-0417.1}, url = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/07-0417.1}, author = {S.G. Baer and John M. Blair} } @article {KNZ001219, title = {Integrating soil ecological knowledge into restoration management}, journal = {Restoration Ecology}, volume = {16}, year = {2008}, pages = {608 -617}, abstract = {

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

}, keywords = {LTER-KNZ, ecosystem processes, feedbacks, Soil ecology}, doi = {10.1111/j.1526-100X.2008.00477.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1526-100X.2008.00477.x}, author = {Heneghan, L. and Miller, S. and S.G. Baer and Callaham, M.A. and Montgomery, J. and Rhoades, C.C. and Richardson, S. and Pauvo-Zuckerman, M.} } @article {KNZ00978, title = {Soil heterogeneity effects on tallgrass prairie community heterogeneity: anapplication of ecological theory to restoration ecology}, journal = {Restoration Ecology}, volume = {13}, year = {2005}, pages = {413 -424}, abstract = {Spatial heterogeneity of resources can influence plant community composition and diversity in natural communities. We manipulated soil depth (two levels) and nutrient availability (three levels) to create four heterogeneity treatments (no heterogeneity, depth heterogeneity, nutrient heterogeneity, and depth + nutrient heterogeneity) replicated in an agricultural field seeded to native prairie species. Our objective was to determine whether resource heterogeneity influences species diversity and the trajectory of community development during grassland restoration. The treatments significantly increased heterogeneity of available inorganic nitrogen (N), soil water content, and light penetration. Plant diversity was indirectly related to resource heterogeneity through positive relationships with variability in productivity and cover established by the belowground manipulations. Diversity was inversely correlated with the average cover of the dominant grass, Switchgrass (Panicum virgatum), which increased over time in all heterogeneity treatments and resulted in community convergence among the heterogeneity treatments over time. The success of this cultivar across the wide range of resource availability was attributed to net photosynthesis rates equivalent to or higher than those of the native prairie plants in the presence of lower foliar N content. Our results suggest that resource heterogeneity alone may not increase diversity in restorations where a dominant species can successfully establish across the range of resource availability. This is consistent with theory regarding the role of ecological filters on community assembly in that the establishment of one species best adapted for the physical and biological conditions can play an inordinately important role in determining community structure.}, keywords = {LTER-KNZ, grassland, Panicum virgatum, restoration, soil heterogeneity, switchgrass, tallgrass prairie}, doi = {10.1111/j.1526-100X.2005.00051.x}, author = {S.G. Baer and Scott. L. Collins and John M. Blair and Fiedler, A. and Alan K. Knapp} } @article {KNZ00889, title = {Plant community responses to resource availability and heterogeneity during restoration}, journal = {Oecologia}, volume = {139}, year = {2004}, pages = {617 -629}, abstract = {Availability and heterogeneity of resources have a strong influence on plant community structure in undisturbed systems, as well as those recovering from disturbance. Less is known about the role of resource availability and heterogeneity in restored communities, although restoration provides a valuable opportunity to test our understanding of factors that influence plant community assembly. We altered soil nitrogen (N) availability and soil depth during a prairie restoration to determine if the availability and/or heterogeneity of soil resources influenced plant community composition in restored grassland communities. Plant community responses to three levels of N availability (ambient, enriched by fertilization, and reduced by carbon amendment) and two levels of soil depth (deep and shallow) were evaluated. In addition, we evaluated plant community responses to four whole plot heterogeneity treatments created from the six possible combinations of soil N availability and soil depth. The soil depth treatment had little influence on community structure during the first 3 years of restoration. Total diversity and richness declined over time under annual N enrichment, whereas diversity was maintained and richness increased over time in soil with reduced N availability. Non-native species establishment was lowest in reduced-N soil in the initial year, but their presence was negligible in all of the soil N treatments by the second year of restoration. Panicum virgatum, a native perennial C4 grass, was the dominant species in all soil N treatments by year three, but the magnitude of its dominance was lowest in the reduced-N soil and highest in enriched-N soil. Consequently, the relative cover of P. virgatum was strongly correlated with community dominance and inversely related to diversity. The differential growth response of P. virgatum to soil N availability led to a higher degree of community similarity to native prairie in the reduced-N treatment than in the enriched-N treatment. There were no differences in plant community structure among the four whole plot-level heterogeneity treatments, which all exhibited the same degree of similarity to native prairie. Diversity and community heterogeneity in the whole-plot treatments appeared to be regulated by the dominant species{\textquoteright} effect on light availability, rather than soil N heterogeneity per se. Our results indicate that a strong differential response of a dominant species to resource availability in a restored community can regulate community structure, diversity, and similarity to the native (or target) community, but the importance of resource heterogeneity in restoring diversity may be dampened in systems where a dominant species can successfully establish across a range of resource availability.}, keywords = {LTER-KNZ, diversity, grassland, nitrogen, tallgrass prairie}, doi = {10.1007/s00442-004-1541-3}, author = {S.G. Baer and John M. Blair and Scott. L. Collins and Alan K. Knapp} } @article {KNZ00822, title = {Soil resources regulate productivity and diversity in newly established tallgrass prairie}, journal = {Ecology}, volume = {84}, year = {2003}, pages = {724 -735}, abstract = {In native tallgrass prairie, soil depth and nitrogen (N) availability strongly influence aboveground net primary productivity (ANPP) and plant species composition. We manipulated these factors in a newly restored grassland to determine if these resources similarly constrain productivity and diversity during the initial three years of grassland establishment. Four types of experimental plots with six treatment combinations of deep and shallow soil at reduced-, ambient-, and enriched-N availability formed the basis of this study. The soil responses to the experimental treatments were examined over three years, and patterns in diversity and productivity were examined in year 3. The soil depth treatment did not significantly affect soil carbon (C) and N pools or ANPP and diversity. A pulse amendment of C added to the soil prior to planting increased soil microbial biomass and decreased potential net N mineralization rates to effectively reduce N availability throughout the study. Nitrogen availability declined over time in nonamended soils as a result of plant establishment, but adding fertilizer N alleviated the increasing immobilization potential of the soil. The level of ANPP was lowest and diversity highest in the reduced-N treatment, whereas the enriched-N treatment resulted in high productivity, but low diversity. As a result, diversity was inversely correlated with productivity in these newly established communities. The same mechanism invoked to explain decreased diversity under nutrient enrichment in old-field ecosystems and native grasslands (e.g., reduced light availability with increased production) was supported in the restored prairie by the positive relationship between ANPP and intercepted light, and a strong correlation between light availability and diversity. The effects of nutrient availability on plant community composition (diversity and richness) were due primarily to the responses of prairie species, as the productivity of early successional, nonprairie species was less than 1\% of total ANPP after three years of establishment. These results show that the effects of resource availability on productivity and diversity are similar in young and mature grasslands, and that manipulation of a limiting nutrient during grassland establishment can influence floristic composition, with consequences for long-term patterns of diversity in restored ecosystems.}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.1890/0012-9658(2003)084[0724:SRRPAD]2.0.CO;2}, author = {S.G. Baer and John M. Blair and Alan K. Knapp and Scott. L. Collins} } @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} } @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} } @article {KNZ00719, title = {Assessment of soil quality in fields with short- and long-term enrollment in the CRP}, journal = {Journal of Soil and Water Conservation}, volume = {55}, year = {2000}, pages = {142 -146}, abstract = {Surface [5 to10 cm, (2 to 4 in) depth] soil quality was examined from fields representing short and long term enrollment in the Conservation Reserve Program (CRP). Total carbon (C) and nitrogen (N) amounts were similar in soil with recent and long term enrollment in the CRP and were lower than a native prairie field. Active pools of C and N, however, did increase through the CRP. Soil with long term establishment of native grasses in the CRP exhibited 141\% and 33\% greater microbial biomass C and N, respectively, than soil recently enrolled in the CRP. Total inorganic N was significantly lower in CRP soil with ten versus no growing seasons and was more representative of levels in a native prairie due to reductions in nitrate availability. Our study indicates that CRP promotes soil restoration; however, ten growing seasons are not adequate for recovery of total soil C and N pools at this depth to pre-cultivation levels.}, keywords = {LTER-KNZ}, url = {http://www.jswconline.org/content/55/2/142.abstract}, author = {S.G. Baer and C. W. Rice and John M. Blair} } @proceedings {KNZ00672, title = {Manipulation of soil resource heterogeneity in a tallgrass prairie restoration}, year = {1999}, pages = {78 -87}, publisher = {University of Nebraska at Kearney}, address = {Kearney, NE}, abstract = {Plant species diversity in native prairie ecosystems is influenced by heterogeneity of soil resources, which results from interactions among plant communities, soil properties, topography, and disturbance. Key factors which promote plant diversity in native prairie include soil moisture, rooting depth, and nutrient availability. Most prairie restorations in the Great Plains occur on former agricultural land and the soil template for these restorations has been physically homogenized through tillage practices. The reduction in soil resource heterogeneity in restored prairies may be causally related to low plant species diversity commonly encountered in these sites. To examine the role of soil heterogeneity in restoring prairie ecosystems, replicated blocks (n=4) of 4 plots consisting of different levels of soil heterogeneity were established in an agricultural field. The 4 plot types included: control (least heterogeneous with respect to soil resources), altered plant rooting depth, altered nutrient availability, and combined variation in plant rooting depth and nutrient availability (maximum heterogeneity). Plant rooting depth was varied by burying limestone barriers at 25 cm to create alternating strips of deep and shallow soil. Variation in soil nutrient (inorganic N) availability was established via increased N (+fertilizer), decreased N (+ recalcitrant C), and no change in N. All plots were seeded with the dominant native grasses and >30 forb species. Incorporation of recalcitrant C reduced total inorganic N availability 90\% as a result of 98\% reduction in available nitrate. Plots containing strips of low N availability exhibited significantly (p < 0.05) greater spatial variability than plots without this manipulation. Thus, the experimental design and methods implemented have increased heterogeneity of soil nutrients, and this will enable us to address the role of variation in soil resources on restoring tallgrass prairie.}, keywords = {LTER-KNZ, altered plant rooting depth, altered soil nutrient availability, Great Plains, limestone barriers, recalcitrant C, soil template, Species diversity}, url = {http://images.library.wisc.edu/EcoNatRes/EFacs/NAPC/NAPC16/reference/econatres.napc16.sbaer.pdf}, author = {S.G. Baer and John M. Blair and Alan K. Knapp}, editor = {Springer, J.T.} }