@article {6301, title = {Grassland sensitivity to drought is related to functional composition across East Asia and North America}, journal = {Ecology}, year = {In Press}, keywords = {LTER-KNZ}, doi = {10.1002/ecy.4220}, url = {https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecy.4220}, author = {Song, Lin and Griffin-Nolan, Robert J. and Muraina, Taofeek O. and Chen, Jiaqi and Te, Niwu and Shi, Yuan and Whitney, Kenneth D. and Zhang, Bingchuan and Yu, Qiang and M. D. Smith and Zuo, Xiaoan and Wang, Zhengwen and Alan K. Knapp and Han, Xingguo and S.L Collins and Luo, Wentao} } @article {6270, title = {How low can you go? Widespread challenges in measuring low stream discharge and a path forward}, journal = {Limnology and Oceanography Letters}, year = {In Press}, keywords = {LTER-KNZ}, doi = {10.1002/lol2.10356}, url = {https://aslopubs.onlinelibrary.wiley.com/doi/full/10.1002/lol2.10356}, author = {Seybold, Erin C. and Bergstrom, Anna and Jones, C. Nathan and Burgin, Amy J. and Zipper, Sam and Godsey, Sarah E. and W. K. Dodds and Zimmer, Margaret A. and Shanafield, Margaret and Datry, Thibault and Mazor, Raphael D. and Messager, Mathis L. and Olden, Julian D. and Ward, Adam and Yu, Songyan and Kaiser, Kendra E. and Shogren, Arial and Walker, Richard H.} } @article {6266, title = {Nothing lasts forever: Dominant species decline under rapid environmental change in global grasslandsAbstract}, journal = {Journal of Ecology}, year = {In Press}, keywords = {LTER-KNZ}, doi = {10.1111/1365-2745.14198}, url = {https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2745.14198}, author = {Wilfahrt, Peter A. and Seabloom, Eric W. and Bakker, Jonathan D. and Biederman, Lori and Bugalho, Miguel N. and Cadotte, Marc W. and Caldeira, Maria C. and Catford, Jane A. and Chen, Qingqing and Donohue, Ian and Ebeling, Anne and Eisenhauer, Nico and Haider, Sylvia and Heckman, Robert W. and Jentsch, Anke and Koerner, S.E. and Komatsu, K.J. and Laungani, Ramesh and MacDougall, Andrew and Martina, Jason P. and Martinson, Holly and Moore, Joslin L. and Niu, Yujie and Ohlert, Timothy and Venterink, Harry Olde and Orr, Devyn and Peri, Pablo and Pos, Edwin and Price, Jodi and Raynaud, Xavier and Ren, Zhengwei and Roscher, Christiane and Smith, Nicholas G. and Stevens, Carly J. and Sullivan, Lauren L. and Tedder, Michelle and Tognetti, Pedro M. and Veen, Ciska and Wheeler, George and Young, Alyssa L. and Young, Hillary and Borer, Elizabeth T.} } @article {KNZ001901, title = {What drives grassland ecosystem multifunctionality: Grazing pressure or plant community parameters?}, journal = {Functional Ecology}, year = {In Press}, keywords = {LTER-KNZ}, author = {Ren, H. and Zhang, Y. and Gui, W. and Yang, G. and G.T. Wilson and Cobb, A.B. and Eviner, V.T. and Hu, S. and Yongfei Bai} } @article {6294, title = {Extreme drought impacts have been underestimated in grasslands and shrublands globally}, journal = {Proceedings of the National Academy of Sciences}, volume = {121}, year = {2024}, pages = {e230988112}, keywords = {LTER-KNZ}, doi = {10.1073/pnas.2309881120}, url = {https://pnas.org/doi/10.1073/pnas.2309881120}, author = {M. D. Smith and Wilkins, Kate D. and Holdrege, Martin C. and Wilfahrt, Peter and S.L Collins and Knapp, Alan K. and Sala, Osvaldo E. and Dukes, Jeffrey S. and Phillips, Richard P. and Yahdjian, Laura and Gherardi, Laureano A. and Ohlert, Timothy and Beier, Claus and Fraser, Lauchlan H. and Jentsch, Anke and Loik, Michael E. and Maestre, Fernando T. and Power, Sally A. and Yu, Qiang and Felton, Andrew J. and Munson, Seth M. and Luo, Yiqi and Abdoli, Hamed and Abedi, Mehdi and Alados, Concepci{\'o}n L. and Alberti, Juan and Alon, Moshe and An, Hui and Anacker, Brian and Anderson, Maggie and Auge, Harald and Bachle, Seton and Bahalkeh, Khadijeh and Bahn, Michael and Batbaatar, Amgaa and Bauerle, Taryn and Beard, Karen H. and Behn, Kai and Beil, Ilka and Biancari, Lucio and Blindow, Irmgard and Bondaruk, Viviana Florencia and Borer, Elizabeth T. and Bork, Edward W. and Bruschetti, Carlos Martin and Byrne, Kerry M. and Cahill Jr., James F. and Calvo, Dianela A. and Carbognani, Michele and Cardoni, Augusto and Carlyle, Cameron N. and Castillo-Garcia, Miguel and Chang, Scott X. and Chieppa, Jeff and Cianciaruso, Marcus V. and Cohen, Ofer and Cordeiro, Amanda L. and Cusack, Daniela F. and Dahlke, Sven and Daleo, Pedro and D{\textquoteright}Antonio, Carla M. and Dietterich, Lee H. and S. Doherty, Tim and Dubbert, Maren and Ebeling, Anne and Eisenhauer, Nico and Fischer, Fel{\'\i}cia M. and Forte, T{\textquoteright}ai G. W. and Gebauer, Tobias and Gozalo, Beatriz and Greenville, Aaron C. and Guidoni-Martins, Karlo G. and Hannusch, Heather J. and Vats{\o} Haugum, Siri and Hautier, Yann and Hefting, Mariet and Henry, Hugh A. L. and Hoss, Daniela and Ingrisch, Johannes and Iribarne, Oscar and Isbell, Forest and Johnson, Yari and Jordan, Samuel and Kelly, Eugene F. and Kimmel, Kaitlin and Kreyling, Juergen and Kr{\"o}el-Dulay, Gy{\"o}rgy and Kr{\"o}pfl, Alicia and K{\"u}bert, Angelika and Kulmatiski, Andrew and Lamb, Eric G. and Larsen, Klaus Steenberg and Larson, Julie and Lawson, Jason and Leder, Cintia V. and Linst{\"a}dter, Anja and Liu, Jielin and Liu, Shirong and Lodge, Alexandra G. and Longo, Grisel and Loydi, Alejandro and Luan, Junwei and Curtis Lubbe, Frederick and Macfarlane, Craig and Mackie-Haas, Kathleen and Malyshev, Andrey V. and Maturano-Ruiz, {\'a}n and Merchant, Thomas and Metcalfe, Daniel B. and Mori, Akira S. and Mudongo, Edwin and Newman, Gregory S. and Nielsen, Uffe N. and Nimmo, Dale and Niu, Yujie and Nobre, Paola and O{\textquoteright}Connor, Rory C. and Ogaya, Rom{\`a} and O{\~n}atibia, Gast{\'o}n R. and Orb{\'a}n, Ildik{\'o} and Osborne, Brooke and Otfinowski, Rafael and P{\"a}rtel, Meelis and Pe{\~n}uelas, Josep and Peri, Pablo L. and Peter, Guadalupe and Petraglia, Alessandro and Picon-Cochard, Catherine and Pillar, Val{\'e}rio D. and Pi{\~N}Eiro-Guerra, Juan Manuel and Ploughe, Laura W. and Plowes, Robert M. and Portales-Reyes, Cristy and Prober, Suzanne M. and Pueyo, Yolanda and Reed, Sasha C. and Ritchie, Euan G. and Rodr{\'\i}guez, Ayl{\'e}n and Rogers, William E. and Roscher, Christiane and S{\'a}nchez, Ana M. and Santos, Br{\'a}ulio A. and Scarf{\'o}, Mar{\'\i}a and Seabloom, Eric W. and Shi, Baoku and Souza, Lara and Stampfli, Andreas and Standish, Rachel J. and Sternberg, Marcelo and Sun, Wei and S{\"u}nnemann, Marie and Tedder, Michelle and Thorvaldsen, {\r a}l and Tian, Dashuan and Tielb{\"o}rger, Katja and Valdecantos, Alejandro and van den Brink, Liesbeth and Vandvik, Vigdis and Vankoughnett, Mathew R. and Guri Velle, Liv and Wang, Changhui and Wang, Yi and Wardle, Glenda M. and Werner, Christiane and Wei, Cunzheng and Wiehl, Georg and Williams, Jennifer L. and Wolf, Amelia A. and Zeiter, Michaela and Zhang, Fawei and Zhu, Juntao and Zong, Ning and Zuo, Xiaoan} } @article {6125, title = {Making sense of multivariate community responses in global change experiments}, journal = {Ecosphere}, volume = {13}, year = {2022}, pages = {e4249}, keywords = {LTER-KNZ}, doi = {10.1002/ecs2.4249}, url = {https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecs2.4249}, author = {M.L. Avolio and Kimberly J. Komatsu and Koerner, S.E. and Grman, Emily and Isbell, Forest and Johnson, David S. and K.R. Wilcox and Alatalo, Juha M. and Baldwin, Andrew H. and Beierkuhnlein, Carl and Britton, Andrea J. and Foster, Bryan L. and Harmens, Harry and Kern, Christel C. and Li, Wei and McLaren, Jennie R. and Reich, Peter B. and Souza, Lara and Yu, Qiang and Zhang, Yunhai} } @article {6050, title = {N and P constrain C in ecosystems under climate change: role of nutrient redistribution, accumulation, and stoichiometry}, journal = {Ecological Applications}, volume = {32}, year = {2022}, pages = {e2684}, keywords = {LTER-KNZ}, doi = {10.1002/eap.2684}, url = {https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/eap.2684}, author = {Rastetter, E.B. and Kwiakowski, B.L. and Kicklighter, D.W. and Barker Plotkin, A. and Genet, H. and Jesse B. Nippert and O{\textquoteright}Keefe, K. and Perakis, S.R. and Porder, S. and Roley, S.S. and Reuss, R.W. and Thompson, J.R. and Wieder, W.R. and K.R. Wilcox and Yanai, R.D.} } @article {6110, title = {Nutrient identity modifies the destabilising effects of eutrophication in grasslands}, journal = {Ecology Letters}, volume = {259}, year = {2022}, pages = {754 - 765}, abstract = {

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

}, keywords = {LTER-KNZ}, issn = {1461-023X}, doi = {10.1111/ele.v25.410.1111/ele.13946}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/ele.13946}, author = {Carroll, Oliver and Batzer, Evan and Bharath, Siddharth and Borer, Elizabeth T. and Campana, {\'\i}a and Esch, Ellen and Hautier, Yann and Ohlert, Timothy and Seabloom, Eric W. and Adler, Peter B. and Bakker, Jonathan D. and Biederman, Lori and Bugalho, Miguel N. and Caldeira, Maria and Chen, Qingqing and Davies, Kendi F. and Fay, Philip A. and Knops, Johannes M. H. and Kimberly J. Komatsu and Martina, Jason P. and McCann, Kevin S. and Moore, Joslin L. and Morgan, John W. and Muraina, Taofeek O. and Osborne, Brooke and Risch, Anita C. and Stevens, Carly and Wilfahrt, Peter A. and Yahdjian, Laura and MacDougall, Andrew S.}, editor = {Pe{\~n}uelas, Josep} } @article {KNZ002034, title = {Is a drought a drought in grasslands? Productivity responses to different types of drought}, journal = {Oecologia}, year = {2021}, keywords = {LTER-KNZ}, author = {Carroll, C.J.W. and Slette, I.J. and Griffin-Nolan, R.J. and Baur, L.E. and Hoffman, A.M. and Denton, E.M. and Gray, J.E. and Post, A.K. and Johnston, M.K. and Yu, Q. and Collins, S.L. and Luo, Y. and Smith, M.D. and Knapp, A.K.} } @article {5970, title = {Negative effects of nitrogen override positive effects of phosphorus on grassland legumes worldwide}, journal = {Proceedings of the National Academy of Sciences}, volume = {118}, year = {2021}, pages = {e2023718118}, keywords = {LTER-KNZ}, doi = {10.1073/pnas.2023718118}, url = {http://www.pnas.org/lookup/doi/10.1073/pnas.2023718118}, author = {Tognetti, Pedro M. and Prober, Suzanne M. and B{\'a}ez, Selene and Chaneton, Enrique J. and Firn, Jennifer and Risch, Anita C. and Schuetz, Martin and Simonsen, Anna K. and Yahdjian, Laura and Borer, Elizabeth T. and Seabloom, Eric W. and Arnillas, Carlos Alberto and Bakker, Jonathan D. and Brown, Cynthia S. and Cadotte, Marc W. and Caldeira, Maria C. and Daleo, Pedro and Dwyer, John M. and Fay, Philip A. and Gherardi, Laureano A. and Hagenah, Nicole and Hautier, Yann and Kimberly J. Komatsu and McCulley, Rebecca L. and Price, Jodi N. and Standish, Rachel J. and Stevens, Carly J. and Wragg, Peter D. and Sankaran, Mahesh} } @article {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 {6003, title = {Why coordinated distributed experiments should go global}, journal = {BioScience}, volume = {71}, year = {2021}, pages = {918 - 927}, keywords = {LTER-KNZ}, doi = {10.1093/biosci/biab033}, url = {https://academic.oup.com/bioscience/article/71/9/918/6259352}, author = {Yahdjian, Laura and Sala, Osvaldo E and Pi{\~N}Eiro-Guerra, Juan Manuel and Alan K. Knapp and Collins, Scott L. and Phillips, Richard P and M. D. Smith} } @article {KNZ002029, title = {Global impacts of fertilization and herbivore removal on soil net nitrogen mineralization are modulated by local climate and soil properties}, journal = {Global Change Biology}, volume = {26}, year = {2020}, abstract = {

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

}, keywords = {LTER-KNZ}, doi = {10.1111/gcb.15308}, url = {https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.15308}, author = {Risch, Anita C. and Zimmermann, Stefan and Moser, Barbara and Sch{\"u}tz, Martin and Hagedorn, Frank and Firn, Jennifer and Fay, Philip A. and Adler, Peter B. and Biederman, Lori A. and J. M. Blair and Borer, Elizabeth T. and Broadbent, Arthur A. D. and Brown, Cynthia S. and Cadotte, Marc W. and Caldeira, Maria C. and Davies, Kendi F. and Virgilio, Augustina and Eisenhauer, Nico and Eskelinen, Anu and Knops, Johannes M. H. and MacDougall, Andrew S. and McCulley, Rebecca L. and Melbourne, Brett A. and Moore, Joslin L. and Power, Sally A. and Prober, Suzanne M. and Seabloom, Eric W. and Siebert, Julia and Silveira, Maria L. and Speziale, Karina L. and Stevens, Carly J. and Tognetti, Pedro M. and Virtanen, Risto and Yahdjian, Laura and Ochoa-Hueso, Raul} } @article {KNZ002001, title = {Mass ratio effects underlie ecosystem responses to environmental change}, journal = {Journal of Ecology}, volume = {108}, year = {2020}, pages = {855-864}, abstract = {

1. Random species loss has been shown experimentally to reduce ecosystem function, sometimes more than other anthropogenic environmental changes. Yet, controversy surrounds the importance of this finding for natural systems where species loss is non-random.
2. We compiled data from 16 multi-year experiments located at a single native tallgrass prairie site. These experiments included responses to 11 anthropogenic environmental changes, as well as non-random biodiversity loss either the removal of uncommon/rare plant species or the most common (dominant) species.
3. As predicted by the mass ratio hypothesis, loss of a dominant species had large impacts on productivity that were comparable to other anthropogenic drivers. In contrast, the loss of uncommon/rare species had small effects on productivity despite having the largest effects on species richness.
4. The anthropogenic drivers that had the largest effects on productivity nitrogen, irrigation, and fire experienced not only loss of species but also significant changes in the abundance and identity of dominant species.
5. Synthesis. These results suggest that mass ratio effects, rather than species loss per se, are an important determinant of ecosystem function with environmental change.

}, keywords = {LTER-KNZ}, doi = {10.1111/1365-2745.13330}, url = {https://besjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1365-2745.13330}, author = {M.D. Smith and Koerner, S.E. and Alan K. Knapp and M.L. Avolio and Chaves, F.A. and Denton, E.M. and Dietrich, J. and Gibson, D.J. and Gray, J. and Hoffman, A.M. and Hoover, D.L. and Kimberly J. Komatsu and Silletti, A. and K.R. Wilcox and Yu, Q. and John M. Blair} } @article {KNZ002004, title = {Nutrient addition increases grassland sensitivity to droughts}, journal = {Ecology}, volume = {101}, year = {2020}, pages = {e02981}, abstract = {

Grasslands worldwide are expected to experience an increase in extreme events such as drought, along with simultaneous increases in mineral nutrient inputs as a result of human industrial activities. These changes are likely to interact because elevated nutrient inputs may alter plant diversity and increase the sensitivity to droughts. Dividing a system\’s sensitivity to drought into resistance to change during the drought and rate of recovery after the drought generates insights into different dimensions of the system\’s resilience in the face of drought. Here, we examine the effects of experimental nutrient fertilization and the resulting diversity loss on the resistance to and recovery from severe regional droughts. We do this at 13 North American sites spanning gradients of aridity, five annual grasslands in California, and eight perennial grasslands in the Great Plains. We measured rate of resistance as the change in annual aboveground biomass (ANPP) per unit change in growing season precipitation as conditions declined from normal to drought. We measured recovery as the change in ANPP during the postdrought period and the return to normal precipitation. Resistance and recovery did not vary across the 400-mm range of mean growing season precipitation spanned by our sites in the Great Plains. However, chronic nutrient fertilization in the Great Plains reduced drought resistance and increased drought recovery. In the California annual grasslands, arid sites had a greater recovery postdrought than mesic sites, and nutrient addition had no consistent effects on resistance or recovery. Across all study sites, we found that predrought species richness in natural grasslands was not consistently associated with rates of resistance to or recovery from the drought, in contrast to earlier findings from experimentally assembled grassland communities. Taken together, these results suggest that human-induced eutrophication may destabilize grassland primary production, but the effects of this may vary across regions and flora, especially between perennial and annual-dominated grasslands.

}, keywords = {LTER-KNZ}, doi = {10.1002/ecy.2981}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/ecy.2981}, author = {Bharath, Siddharth and E.T. Borer and L.A. Biederman and D.M. Blumenthal and Fay, Philip A. and Gherardi, Laureano A. and Knops, Johannes M. H. and Leakey, Andrew D. B. and Yahdjian, Laura and Seabloom, Eric W.} } @article {5802, title = {Soil structure~is an important omission in Earth System Models}, journal = {Nature Communications}, volume = {11}, year = {2020}, abstract = {

Most soil hydraulic information used in Earth System Models (ESMs) is derived from pedo-transfer functions that use easy-to-measure soil attributes to estimate hydraulic parameters. This parameterization relies heavily on soil texture, but overlooks the critical role of soil structure originated by soil biophysical activity. Soil structure omission is pervasive also in sampling and measurement methods used to train pedotransfer functions. Here we show how systematic inclusion of salient soil structural features of biophysical origin affect local and global hydrologic and climatic responses. Locally, including soil structure in models significantly alters infiltration-runoff partitioning and recharge in wet and vegetated regions. Globally, the coarse spatial resolution of ESMs and their inability to simulate intense and short rainfall events mask effects of soil structure on surface fluxes and climate. Results suggest that although soil structure affects local hydrologic response, its implications on global-scale climate remains elusive in current ESMs.

}, keywords = {LTER-KNZ}, doi = {10.1038/s41467-020-14411-z}, url = {http://www.nature.com/articles/s41467-020-14411-z}, author = {Fatichi, Simone and Or, Dani and Walko, Robert and Vereecken, Harry and Young, Michael H. and Ghezzehei, Teamrat A. and Hengl, Tomislav and Kollet, Stefan and Agam, Nurit and Avissar, Roni} } @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 {KNZ001965, title = {Global change effects on plant communities are magnified by time and the number of global change factors imposed}, journal = {Proceedings of the National Academy of Sciences}, volume = {116}, year = {2019}, pages = {17867-17873}, abstract = {

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

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

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

}, keywords = {LTER-KNZ}, doi = {10.1126/sciadv.aav0486}, url = {http://advances.sciencemag.org/content/5/1/eaav0486}, author = {Tiegs, Scott D. and Costello, David M. and Isken, Mark W. and Woodward, Guy and McIntyre, Peter B. and Gessner, Mark O. and Chauvet, Eric and Griffiths, Natalie A. and Flecker, Alex S. and Acu{\~n}a, Vicenc and Albari{\~n}o, Ricardo and Allen, Daniel C. and Alonso, Cecilia and Andino, Patricio and Arango, Clay and Aroviita, Jukka and Barbosa, Marcus V. M. and Barmuta, Leon A. and Baxter, Colden V. and Bell, Thomas D. C. and Bellinger, Brent and Boyero, Luz and Brown, Lee E. and Bruder, Andreas and Bruesewitz, Denise A. and Burdon, Francis J. and Callisto, Marcos and Canhoto, Cristina and Capps, Krista A. and Castillo, Mar{\'\i}a M. and Clapcott, Joanne and Colas, Fanny and Col{\'o}n-Gaud, Checo and Cornut, Julien and Crespo-P{\'e}rez, Ver{\'o}nica and Cross, Wyatt F. and Culp, Joseph M. and Danger, Michael and Dangles, Olivier and de Eyto, Elvira and Derry, Alison M. and Villanueva, {\'\i}az and Douglas, Michael M. and Elosegi, Arturo and Encalada, Andrea C. and Entrekin, Sally and Espinosa, Rodrigo and Ethaiya, Diana and Ferreira, Ver{\'o}nica and Ferriol, Carmen and Flanagan, Kyla M. and Fleituch, Tadeusz and Follstad Shah, Jennifer J. and Frainer Barbosa, Andr{\'e} and Friberg, Nikolai and Frost, Paul C. and Garcia, Erica A. and Garc{\'\i}a Lago, Liliana and Garc{\'\i}a Soto, Pavel Ernesto and Ghate, Sudeep and Giling, Darren P. and Gilmer, Alan and {\c c}alves, Jos{\'e} Francisco and Gonzales, Rosario Karina and Graca, Manuel A. S. and Grace, Mike and Grossart, Hans-Peter and Guerrold, Francois and Gulis, Vlad and Hepp, Luiz U. and Higgins, Scott and Hishi, Takuo and Huddart, Joseph and Hudson, John and Imberger, Samantha and {\~n}iguez-Armijos, Carlos and Iwata, Tomoya and Janetski, David J. and Jennings, Eleanor and Kirkwood, Andrea E. and Koning, Aaron A. and Kosten, Sarian and Kuehn, Kevin A. and Laudon, Hjalmar and Leavitt, Peter R. and Lemes da Silva, Aurea L. and Leroux, Shawn J. and LeRoy, Carri J. and Lisi, Peter J. and MacKenzie, Richard and Marcarelli, Amy M. and Masese, Frank O. and McKie, Brendan G. and Oliveira Medeiros, Adriana and Meissner, Kristian and Mili{\v s}a, Marko and Mishra, Shailendra and Miyake, Yo and Moerke, Ashley and Mombrikotb, Shorok and Mooney, Rob and Moulton, Tim and Muotka, Timo and Negishi, Junjiro N. and Neres-Lima, Vinicius and Nieminen, Mika L. and Nimptsch, Jorge and Ondruch, Jakub and Paavola, Riku and Pardo, Isabel and Patrick, Christopher J. and Peeters, Edwin T. H. M. and Pozo, Jesus and Pringle, Catherine and Prussian, Aaron and Quenta, Estefania and Quesada, Antonio and Reid, Brian and Richardson, John S. and Rigosi, Anna and Rinc{\'o}n, Jos{\'e} and Risnoveanu, Geta and Robinson, Christopher T. and Rodr{\'\i}guez-Gallego, Lorena and Royer, Todd V. and Rusak, James A. and Santamans, Anna C. and Selmeczy, G{\'e}za B. and Simiyu, Gelas and Skuja, Agnija and Smykla, Jerzy and Sridhar, Kandikere R. and Sponseller, Ryan and Stoler, Aaron and Swan, Christopher M. and Szlag, David and Mello, Franco Teixeira-de and Tonkin, Jonathan D. and Uusheimo, Sari and Veach, Allison M. and Vilbaste, Sirje and Vought, Lena B. M. and Wang, Chiao-Ping and Webster, Jackson R. and Wilson, Paul B. and Woelfl, Stefan and Xenopoulos, Marguerite A. and Yates, Adam G. and Yoshimura, Chihiro and Yule, Catherine M. and Zhang, Yixin X. and Zwart, Jacob A.} } @article {KNZ001981, title = {Phosphorus and mowing improve native alfalfa establishment, facilitating restoration of grassland productivity and diversity}, journal = {Land Degradation \& Development}, volume = {30}, year = {2019}, pages = {647 - 657}, keywords = {LTER-KNZ}, doi = {10.1002/ldr.v30.610.1002/ldr.3251}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/ldr.3251}, author = {Zhou, Jiqiong and G.T. Wilson and Cobb, Adam B. and Yang, Gaowen and Zhang, Yingjun} } @article {KNZ001985, title = {Soil net nitrogen mineralisation across global grasslands}, journal = {Nature Communications}, volume = {10}, year = {2019}, abstract = {

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

}, keywords = {LTER-KNZ}, doi = {10.1038/s41467-019-12948-2}, url = {http://www.nature.com/articles/s41467-019-12948-2}, author = {Risch, A.C. and Zimmermann, S. and Ochoa-Hueso, R. and sch{\"u}tz, M. and Frey, B. and Firn, J. L. and Fay, P. A. and Hagedorn, F. and E.T. Borer and Seabloom, E. W. and Harpole, W. S. and Knops, J. M. H. and McCulley, R. L. and Broadbent, A. A. D. and Stevens, C. J. and Silveira, M. L. and P. Adler and B{\'a}ez, S. and L.A. Biederman and John M. Blair and Brown, C. S. and Caldeira, M. C. and Scott. L. Collins and Daleo, P. and di Virgilio, A. and Ebeling, A. and Eisenhauer, N. and Esch, E. and Eskelinen, A. and Hagenah, N. and Hautier, Y. and Kirkman, K. P. and MacDougall, A. S. and Joslin L. Moore and Power, S. A. and Prober, S. M. and Roscher, C. and Sankaran, M. and Siebert, J. and Speziale, K. L. and Tognetti, P. M. and Virtanen, R. and Yahdjian, L. and Moser, B.} } @article {KNZ001888, title = {Change in dominance determines herbivore effects on plant biodiversity}, journal = {Nature Ecology and Evolution}, volume = {2}, year = {2018}, pages = {1925-1932}, abstract = {

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

}, keywords = {LTER-KNZ}, doi = {https://doi.org/10.1038/s41559-018-0696-y}, url = {https://www.nature.com/articles/s41559-018-0696-y$\#$article-info}, author = {Koerner, S.E. and M.D. Smith and Burkepile, D.E. and N.P. Hanan and M.L. Avolio and Scott. L. Collins and Alan K. Knapp and N.P. Lemoine and E.J. Forrestel and S. Eby and D.I. Thompson and G. Aguado-Santacruz and J.P. Anderson and Anderson, M. and A. Angassa and S. Bagchi and E.S. Bakker and Bastin, Gary and L.E. Baur and K.H. Beard and E.A. Beever and P.J. Bohlen and Elizabeth H. Boughton and Canestro, Don and Cesa, Ariela and Chaneton, Enrique and Cheng, Jimin and C.M. D{\textquoteright}Antonio and C. Deleglise and Fadiala. Demb{\'e}l{\'e} and Josh. Dorrough and David. J. Eldridge and Barbara. Fernandez-Going and Silvia. Fern{\'a}ndez-Lugo and Lauchlan. H. Fraser and Bill. Freedman and Gonzalo. Garc{\'\i}a-Salgado and Jacob. R. Goheen and Liang. Guo and Sean. Husheer and Moussa. Karemb{\'e} and Johannes. M. H. Knops and Tineke. Kraaij and Andrew. Kulmatiski and Minna-Maarit. Kyt{\"o}viita and Felipe. Lezama and Gregory. Loucougaray and Alejandro. Loydi, Dan G. Milchunas, and Dan.G. Milchunas, and Suzanne. J. Milton and J.W. Morgan and Claire. Moxham and Kyle. C. Nehring and Han. Olff and Todd. M. Palmer and Salvador. Rebollo and Corinna. Riginos and Anita. C. Risch and Marta Rueda and Mahesh. Sankaran and Takehiro. Sasaki and Kathryn. A. Schoenecker and Nick. L. Schultz and Martin. Sch{\"u}tz and Angelika. Schwabe and Frances. Siebert and Christian. Smit and Karen. A. Stahlheber and Christian. Storm and Dustin. J. Strong and Jishuai. Su and Yadugiri. V. Tiruvaimozhi and Claudia. Tyler and James. Val and Martijn. L. Vandegehuchte and Kari. E. Veblen and Lance. T. Vermeire and David. Ward and Jianshuang. Wu and Truman. P. Young and Qiang. Yu and Tamara. Jane. Zelikova} } @article {KNZ001905, title = {Defoliation and arbuscular mycorrhizal fungi shape plant communities in overgrazed semiarid grasslands}, journal = {Ecology}, volume = {99}, year = {2018}, pages = {1847 - 1856}, abstract = {

Overgrazing substantially contributes to global grassland degradation by decreasing plant community productivity and diversity through trampling, defoliation, and removal of nutrients. Arbuscular mycorrhizal (AM) fungi also play a critical role in plant community diversity, composition, and primary productivity, maintaining ecosystem functions. However, interactions between grazing disturbances, such as trampling and defoliation, and AM fungi in grassland communities are not well known. We examined influences of trampling, defoliation, and AM fungi on semiarid grassland plant community composition for 3\ yr, by comparing all combinations of these factors. Benomyl fungicide was applied to reduce AM fungal abundance. Overgrazing typically resulted in reduced dominance of Stipa Krylovii, contributing to degradation of typical steppe grasslands. Our results indicated trampling generally had little effect on plant community composition, unless combined with defoliation or AM fungal suppression. Defoliation was the main component of grazing that promoted dominance of Potentilla acaulis over Stipa krylovii and Artemisia frigida, presumably by alleviating light limitation. In non-defoliated plots, AM fungi promoted A.\ frigida, with a concomitant reduction in S.\ krylovii growth compared to corresponding AM suppressed plots. Our results indicate AM fungi and defoliation jointly suppress S.\ krylovii biomass; however, prolonged defoliation weakens mycorrhizal influence on plant community composition. These findings give new insight into dominant plant species shifts in degraded semiarid grasslands.

}, keywords = {LTER-KNZ}, doi = {10.1002/ecy.2401}, url = {https://doi.org/10.1002/ecy.2401}, author = {Yang, Xin and Shen, Yue and Liu, Nan and G.T. Wilson and Cobb, Adam B. and Zhang, Yingjun} } @article {KNZ001932, title = {Large and active CO 2 uptake by coupled carbonate weathering}, journal = {Earth-Science Reviews}, volume = {182}, year = {2018}, pages = {42 - 49}, abstract = {

Carbonate mineral weathering coupled with aquatic photosynthesis on the continents, herein termed coupled carbonate weathering (CCW), represents a current atmospheric CO2 sink of about 0.5 Pg C/a. Because silicate mineral weathering has been considered the primary geological CO2 sink, CCW\&$\#$39;s role in the present carbon cycle has been neglected. However, CCW may be helping to offset anthropogenic atmospheric CO2 increases as carbonate minerals weather more rapidly than silicates. Here we provide an overview of atmospheric CO2 uptake by CCW and its impact on global carbon cycling. This overview shows that CCW is linked to climate and land-use change through changes in the water cycle and water-born carbon fluxes. Projections of future changes in carbon cycling should therefore include CCW as linked to the global water cycle and land-use change.

}, keywords = {LTER-KNZ}, doi = {10.1016/j.earscirev.2018.05.007}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0012825217306153}, author = {Liu, Zaihua. and G. L. Macpherson and Groves, Chris. and Martin, J.B. and Yuan, Daoxian. and Zeng, Sibo.} } @article {KNZ001894, title = {Local loss and spatial homogenization of plant diversity reduce ecosystem multifunctionality}, journal = {Nature Ecology \& Evolution}, volume = {2}, year = {2018}, pages = {50-56}, abstract = {

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

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

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


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


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


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

}, keywords = {LTER-KNZ}, doi = {10.1002/ajb2.2018.105.issue-1210.1002/ajb2.1197}, url = {https://bsapubs.onlinelibrary.wiley.com/doi/full/10.1002/ajb2.1197}, author = {Ricono, A. and Dixon, R. and Eaton, I. and Brightbill, C.M. and Yaziji, Y. and Puzey, J.R. and Dalgleish, H.J.} } @article {KNZ001903, title = {Long-term effects of grazing and topography on extra-radical hyphae of arbuscular mycorrhizal fungi in semi-arid grasslands}, journal = {Mycorrhiza}, volume = {28}, year = {2018}, pages = {117 - 127}, abstract = {

Grazing and topography have drastic effects on plant communities and soil properties. These effects are thought to influence arbuscular mycorrhizal (AM) fungi. However, the simultaneous impacts of grazing pressure (sheep\ ha-1) and topography on plant and soil factors and their relationship to the production of extra-radical AM hyphae are not well understood. Our 10-year study assessed relationships between grazing, plant species richness, aboveground plant productivity, soil nutrients, edaphic properties, and AM hyphal length density (HLD) in different topographic areas (flat or sloped). We found HLD linearly declined with increasing grazing pressure (1.5-9.0 sheep\ ha-1) in sloped areas, but HLD was greatest at moderate grazing pressure (4.5 sheep\ ha-1) in flat areas. Structural equation modeling indicates grazing reduces HLD by altering soil nutrient dynamics in sloped areas, but non-linearly influences HLD through plant community and edaphic changes in flat areas. Our findings highlight how topography influences key plant and soil factors, thus regulating the effects of grazing pressure on extra-radical hyphal production of AM fungi in grasslands. Understanding how grazing and topography influence AM fungi in semi-arid grasslands is vital, as globally, severe human population pressure and increasing demand for food aggravate the grazing intensity in grasslands.

}, keywords = {LTER-KNZ}, doi = {10.1007/s00572-017-0812-x}, url = {http://link.springer.com/10.1007/s00572-017-0812-x}, author = {Ren, Haiyan and Gui, Weiyang and Yongfei Bai and Stein, Claudia and Rodrigues, Jorge L. M. and G.T. Wilson and Cobb, Adam B. and Zhang, Yingjun and Yang, Gaowen} } @article {KNZ001900, title = {Plant functional group influences arbuscular mycorrhizal fungal abundance and hyphal contribution to soil CO2 efflux in temperate grasslands}, journal = {Plant and Soil}, volume = {432}, year = {2018}, pages = {157-170}, abstract = {

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


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


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


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

}, keywords = {LTER-KNZ}, doi = {10.1007/s11104-018-3789-0}, url = {http://link.springer.com/10.1007/s11104-018-3789-0}, author = {Gui, Weiyang and Ren, Haiyan and Liu, Nan and Zhang, Yingjun and Cobb, Adam B. and G.T. Wilson and Sun, Xiao and Hu, Jian and Xiao, Yan and Zhang, Fengge and Yang, Gaowen} } @article {KNZ001884, title = {Regional grassland productivity responses to precipitation during multiyear above- and below-average rainfall periods}, journal = {Global Change Biology}, volume = {24}, year = {2018}, pages = {1935 - 1951}, abstract = {

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

}, keywords = {LTER-KNZ}, doi = {10.1111/gcb.2018.24.issue-510.1111/gcb.14024}, url = {https://www.ncbi.nlm.nih.gov/pubmed/29265568}, author = {Petrie, Matthew D. and Peters, Debra P. C. and Yao, Jin and John M. Blair and Burruss, Nathan D. and Scott. L. Collins and Derner, Justin D. and Gherardi, Laureano A. and Hendrickson, John R. and Sala, Osvaldo E. and Starks, Patrick J. and Steiner, Jean L.} } @article {KNZ001904, title = {Trichoderma biofertilizer links to altered soil chemistry, altered microbial communities, and improved grassland biomass}, journal = {Frontiers in Microbiology}, volume = {9}, year = {2018}, pages = {848}, abstract = {

In grasslands, forage and livestock production results in soil nutrient deficits as grasslands typically receive no nutrient inputs, leading to a loss of grassland biomass. The application of mature compost has been shown to effectively increase grassland nutrient availability. However, research on fertilization regime influence and potential microbial ecological regulation mechanisms are rarely conducted in grassland soil. We conducted a two-year experiment in meadow steppe grasslands, focusing on above- and belowground consequences of organic or Trichoderma biofertilizer applications and potential soil microbial ecological mechanisms underlying soil chemistry and microbial community responses. Grassland biomass significantly (p = 0.019) increased following amendment with 9,000 kg ha\−1 of Trichoderma biofertilizer (composted cattle manure + inoculum) compared with other assessed organic or biofertilizer rates, except for BOF3000 (fertilized with 3,000 kg ha\−1 biofertilizer). This rate of Trichoderma biofertilizer treatment increased soil antifungal compounds that may suppress pathogenic fungi, potentially partially responsible for improved grassland biomass. Nonmetric multidimensional scaling (NMDS) revealed soil chemistry and fungal communities were all separated by different fertilization regime. Trichoderma biofertilizer (9,000 kg ha\−1) increased relative abundances of Archaeorhizomyces and Trichoderma while decreasing Ophiosphaerella. Trichoderma can improve grassland biomass, while Ophiosphaerella has the opposite effect as it may secrete metabolites causing grass necrosis. Correlations between soil properties and microbial genera showed plant-available phosphorus may influence grassland biomass by increasing Archaeorhizomyces and Trichoderma while reducing Ophiosphaerella. According to our structural equation modeling (SEM), Trichoderma abundance was the primary contributor to aboveground grassland biomass. Our results suggest Trichoderma biofertilizer could be an important tool for management of soils and ultimately grassland plant biomass.

}, keywords = {LTER-KNZ}, doi = {10.3389/fmicb.2018.00848}, url = {http://journal.frontiersin.org/article/10.3389/fmicb.2018.00848/full}, author = {Zhang, Fengge and Huo, Yunqian and Cobb, Adam B. and Luo, Gongwen and Zhou, Jiqiong and Yang, Gaowen and G.T. Wilson and Zhang, Yingjun} } @article {KNZ001811, title = {Asymmetric responses of primary productivity to precipitation extremes: A synthesis of grassland precipitation manipulation experiments}, journal = {Global Change Biology}, volume = {23}, year = {2017}, month = {4376-4385}, abstract = {

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

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

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

}, keywords = {LTER-KNZ, Alpha diversity, alpha variability, beta diversity, Biodiversity, CoRRE data base, patchiness, Plant communities, Primary productivity, species synchrony}, doi = {10.1111/ele.12861}, url = {http://onlinelibrary.wiley.com/doi/10.1111/ele.12861/epdf}, author = {K.R. Wilcox and Tredennick, Andrew T. and Koerner, Sally E. and Grman, Emily and Hallett, Lauren M. and M.L. Avolio and Kimberly J. La Pierre and Houseman, Gregory R. and Isbell, Forest and Johnson, David Samuel and Juha M. Alatalo and Baldwin, Andrew H. and Edward W. Bork and Elizabeth H. Boughton and W.D. Bowman and Britton, Andrea J. and Cahill, James F. and Scott. L. Collins and G. Du and Eskelinen, Anu and Gough, Laura and Jentsch, Anke and Kern, Christel and Klanderud, Kari and Alan K. Knapp and Kreyling, Juergen and Luo, Yiqi and McLaren, Jennie R. and Megonigal, Patrick and Onipchenko, Vladimir and Prev{\'e}y, Janet and Price, Jodi N. and Robinson, Clare H. and Sala, Osvaldo E. and M.D. Smith and Soudzilovskaia, Nadejda A. and Souza, Lara and Tilman, David and White, Shannon R. and Xu, Zhuwen and Yahdjian, Laura and Yu, Qiang and Zhang, Pengfei and Zhang, Yunhai}, editor = {Gurevitch, Jessica} } @article {KNZ001895, title = {Increased grassland arthropod production with mammalian herbivory and eutrophication: a test of mediation pathways}, journal = {Ecology}, volume = {98}, year = {2017}, pages = {3022-3033}, abstract = {

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

}, keywords = {LTER-KNZ}, doi = {10.1002/ecy.2029}, url = {http://doi.wiley.com/10.1002/ecy.2029}, author = {Lind, Eric M. and Kimberly J. La Pierre and Seabloom, Eric W. and J. Alberti and Iribarne, Oscar and Firn, Jennifer and Gruner, Daniel S. and Kay, Adam D. and Pascal, Jesus and Wright, Justin P. and Yang, Louie and E.T. Borer} } @article {KNZ001783, title = {Pushing precipitation to the extremes in distributed experiments: recommendations for simulating wet and dry years}, journal = {Global Change Biology}, volume = {23}, year = {2017}, pages = {1774-1782}, abstract = {

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

}, keywords = {LTER-KNZ}, doi = {10.1111/gcb.13504}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.13504}, author = {Alan K. Knapp and M.L. Avolio and Beier, C. and Carroll, C.J.W. and Scott. L. Collins and Dukes, J.S. and Fraser, L.H. and Griffin-Nolan, R.J. and Hoover, D.L. and Jentsch, A. and Loik, M.E. and Phillips, R.P. and Post, A.K. and Sala, O.E. and Slette, I.J. and Yahdjian, L. and M.D. Smith} } @article {KNZ001747, title = {Climate modifies response of non-native and native species richness to nutrient enrichment}, journal = {Philosophical Transactions of the Royal Society B: Biological Sciences}, volume = {3719371}, year = {2016}, pages = {20150273}, abstract = {

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

}, keywords = {LTER-KNZ}, issn = {0962-8436}, doi = {10.1098/rstb.2015.0273}, url = {https://royalsocietypublishing.org/doi/10.1098/rstb.2015.0273}, author = {Flores-Moreno, H. and P.B. Reich and Lind, E.M. and L.L. Sullivan and Seabloom, E.W. and Yahdjian, L. and MacDougall, A.S. and Reichmann, L.G. and J. Alberti and B{\'a}ez, S. and J.D. Bakker and Cadotte, M.W. and Caldeira, M.C. and Chaneton, E.J. and D{\textquoteright}Antonio, C.M. and Fay, P.A. and Firn, J. and Hagenah, N. and Harpole, W. S. and Iribarne, O. and Kirkman, K.P. and Knops, J.M. H. and Kimberly J. La Pierre and Laungani, R. and Leakey, A.D. B. and McCulley, R.L. and Joslin L. Moore and Pascual, J. and E.T. Borer} } @article {KNZ001718, title = {Tardigrades of the tree canopy: milnesium swansoni sp.nov. (Eutardigrada: Apochela: Milnesiidae) a new species from Kansas, U.S.A.}, journal = {Zootaxa}, volume = {4072}, year = {2016}, pages = {559-568}, abstract = {

Milnesium swansoni sp. nov. is a new species of Eutardigrada described from the tree canopy in eastern Kansas, USA. This species within the order Apochela, family Milnesiidae, genus Milnesium is distinguished by its smooth cuticle, narrow buccal tube, four peribuccal lamellae, primary claws without accessory points, and a secondary claw configuration of [3-3]-[3-3]. The buccal tube appears to be only half the width of the nominal species Milnesium tardigradum for animals of similar body length. The species adds to the available data for the phylum, and raises questions concerning species distribution.

}, keywords = {LTER-KNZ, Canopy diversity, Four peribuccal lamellae, Tardigrada, Thorpe morphometry}, issn = {1175-5326}, doi = {10.11646/zootaxa.4072.5.3}, url = {https://biotaxa.org/Zootaxa/article/view/zootaxa.4072.5.3}, author = {Young, A and Chappell, B and Miller, W and Lowman, M} } @article {KNZ001689, title = {Global environmental change and the nature of aboveground net primary productivity responses: insights from long-term experiments}, journal = {Oecologia}, volume = {177}, year = {2015}, month = {Jan-04-2015}, pages = {935 - 947}, abstract = {

Many global change drivers chronically alter resource availability in terrestrial ecosystems. Such resource alterations are known to affect aboveground net primary production (ANPP) in the short term; however, it is unknown if patterns of response change through time. We examined the magnitude, direction, and pattern of ANPP responses to a wide range of global change drivers by compiling 73 datasets from long-term (\>5 years) experiments that varied by ecosystem type, length of manipulation, and the type of manipulation. Chronic resource alterations resulted in a significant change in ANPP irrespective of ecosystem type, the length of the experiment, and the resource manipulated. However, the pattern of ecosystem response over time varied with ecosystem type and manipulation length. Continuous directional responses were the most common pattern observed in herbaceous-dominated ecosystems. Continuous directional responses also were frequently observed in longer-term experiments (\>11 years) and were, in some cases, accompanied by large shifts in community composition. In contrast, stepped responses were common in forests and other ecosystems (salt marshes and dry valleys) and with nutrient manipulations. Our results suggest that the response of ANPP to chronic resource manipulations can be quite variable; however, responses persist once they occur, as few transient responses were observed. Shifts in plant community composition over time could be important determinants of patterns of terrestrial ecosystem sensitivity, but comparative, long-term studies are required to understand how and why ecosystems differ in their sensitivity to chronic resource alterations.

}, keywords = {LTER-KNZ, Aboveground productivity, Hierarchical response framework (HRF), Long-Term Ecological Research (LTER) Network, Nutrient addition, Precipitation manipulation}, issn = {0029-8549}, doi = {10.1007/s00442-015-3230-9}, url = {https://link.springer.com/article/10.1007\%2Fs00442-015-3230-9}, author = {M.D. Smith and Kimberly J. La Pierre and Scott. L. Collins and Alan K. Knapp and Gross, K.L. and Barrett, J.E. and Frey, S.D. and Gough, L. and Miller, R.J. and Morris, J.T. and Rustad, L.E. and Yarie, J.} } @article {KNZ001788, title = {Grassland productivity limited by multiple nutrients}, journal = {Nature Plants}, volume = {1}, year = {2015}, pages = {15080}, abstract = {

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

}, keywords = {LTER-KNZ}, doi = {10.1038/nplants.2015.80}, url = {https://www.nature.com/articles/nplants201580}, author = {Fay, P.A. and Prober, S.M. and Harpole, W.S. and Knops, J.M.H. and J.D. Bakker and E.T. Borer and Lind, E.M. and MacDougall, A.S. and Seabloom, E.W. and Wragg, P.D. and P. Adler and D.M. Blumenthal and Buckley, Y.M. and Chu, C. and Cleland, E.E. and Scott. L. Collins and Davies, K.F. and G. Du and Feng, X. and Firn, J. and Gruner, D.S. and Hagenah, N. and Hautier, Y. and Heckman, R.W. and Jin, V.L. and Kirkman, K.P. and Klein, J. and L. Ladwig and Li, Q. and McCulley, R.L. and Melbourne, B.A. and Mitchell, C.E. and Joslin L. Moore and J.W. Morgan and A. Risch and sch{\"u}tz, M. and Stevens, C.J. and Wedin, D.A. and Yang, L.H.} } @article {KNZ001691, title = {Stoichiometric homeostasis predicts plant species dominance, temporal stability and responses to global change}, journal = {Ecology}, volume = {96}, year = {2015}, month = {09/2015}, pages = {2335}, chapter = {2328}, abstract = {

Why some species are consistently more abundant than others, and predicting how species will respond to global change, are fundamental questions in ecology. Long-term observations indicate that plant species with high stoichiometric homeostasis for nitrogen (HN), i.e., the ability to decouple foliar N levels from variation in soil N availability, were more common and stable through time than low HN species in a central US grassland. However, with 9-yrs of nitrogen addition, species with high HN decreased in abundance, while those with low HN increased in abundance. In contrast, in climate change experiments simulating a range of forecast hydrologic changes - extreme drought (2-yrs), increased rainfall variability (14-yrs), and chronic increases in rainfall (21-yrs) - plant species with the highest HN were least responsive to changes in soil water availability. These results suggest that HN may be predictive of plant species success and stability, and how plant species and ecosystems will respond to global-change driven alterations in resource availability.

}, keywords = {LTER-KNZ}, doi = {10.1890/14-1897.1}, url = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/14-1897.1}, author = {Yu, Q. and K.R. Wilcox and Kimberly J. La Pierre and Alan K. Knapp and Han, X. and M.D. Smith} } @article {KNZ001793, title = {Herbivores and nutrients control grassland plant diversity via light limitation}, journal = {Nature}, volume = {508}, year = {2014}, pages = {517 - 520}, keywords = {LTER-KNZ}, doi = {10.1038/nature13144}, url = {https://www.nature.com/articles/nature13144}, author = {E.T. Borer and Seabloom, E.W. and Gruner, D.S. and Harpole, W.S and Hillebrand, H. and Lind, E.M. and P. Adler and J. Alberti and Anderson, T.M. and J.D. Bakker and L.A. Biederman and D.M. Blumenthal and C.S. Brown and Brudvig, L.A. and Buckley, Y.M. and Cadotte, M. and Chu, C. and Cleland, E.E. and Crawley, M.J. and Daleo, P. and Damschen, E.I. and Davies, K.F. and DeCrappeo, N.M. and G. Du and Firn, J. and Hautier, Y. and Heckman, R.W. and Hector, A. and HilleRisLambers, J. and Iribarne, Oscar and Klein, J.A. and Knops, J.M.H. and Kimberly J. La Pierre and Leakey, A.D.B. and Li, W. and MacDougall, A.S. and McCulley, R.L. and Melbourne, B.A. and Mitchell, C.E. and Joslin L. Moore and Mortensen, B. and O{\textquoteright}Halloran, L.R. and Orrock, J.L. and Pascual, J. and Prober, S.M. and Pyke, D.A. and A. Risch and Schuetz, M. and M.D. Smith and Stevens, C.J. and L.L. Sullivan and Williams, R.J. and Wragg, P.D. and Wright, J.P. and Yang, L.H.} } @article {KNZ001542, title = {Dissolved black carbon in grassland streams: is there an effect of recent fire history?}, journal = {Chemosphere}, volume = {90}, year = {2013}, pages = {2557 -2562}, abstract = {

While the existence of black carbon as part of dissolved organic matter (DOM) has been confirmed, quantitative determinations of dissolved black carbon (DBC) in freshwater ecosystem and information on factors controlling its concentration are scarce. In this study, stream surface water samples from a series of watersheds subject to different burn frequencies in Konza Prairie (Kansas, USA) were collected in order to determine if recent fire history has a noticeable effect on DBC concentration. The DBC levels detected ranged from 0.04 to 0.11 mg L\−1, accounting for ca. 3.32 \± 0.51\% of dissolved organic carbon (DOC). No correlation was found between DBC concentration and neither fire frequency nor time since last burn. We suggest that limited DBC flux is related to high burning efficiency, possibly greater export during periods of high discharge and/or the continuous export of DBC over long time scales. A linear correlation between DOC and DBC concentrations was observed, suggesting the export mechanisms determining DOC and DBC concentrations are likely coupled. The potential influence of fire history was less than the influence of other factors controlling the DOC and DBC dynamics in this ecosystem. Assuming similar conditions and processes apply in grasslands elsewhere, extrapolation to a global scale would suggest a global grasslands flux of DBC on the order of 0.14 Mt carbon year\−1.

}, keywords = {LTER-KNZ, BPCA, Dissolved black carbon, Dissolved organic carbon, Fire frequency, Grassland streams, Konza Prairie}, doi = {10.1016/j.chemosphere.2012.10.098}, url = {https://www.sciencedirect.com/science/article/pii/S0045653512013604?via\%3Dihub}, author = {Ding, Y. and Yamashita, Y. and W. K. Dodds and Jaffe, R.} } @article {KNZ001790, title = {Predicting invasion in grassland ecosystems: is exotic dominance the real embarrassment of richness?}, journal = {Global Change Biology}, volume = {19}, year = {2013}, pages = {3677 - 3687}, abstract = {

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

}, keywords = {LTER-KNZ}, doi = {10.1111/gcb.12370}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.12370}, author = {Seabloom, E.W. and E.T. Borer and Buckley, Y. and Cleland, E.E. and Davies, K. and Firn, J. and Harpole, W.S. and Hautier, Y. and Lind, E. and MacDougall, A. and Orrock, J.L. and Prober, S.M. and P. Adler and J. Alberti and Anderson, M.T. and J.D. Bakker and L.A. Biederman and D.M. Blumenthal and C.S. Brown and Brudvig, L.A. and Caldeira, M. and Chu, C. and Crawley, M.J. and Daleo, P. and Damschen, E.I. and D{\textquoteright}Antonio, C.M. and DeCrappeo, N.M. and Dickman, C.R. and G. Du and Fay, P.A. and Frater, P. and Gruner, D.S. and Hagenah, N. and Hector, A. and Helm, A. and Hillebrand, H. and Hofmockel, K.S. and Humphries, H.C. and Iribarne, O. and Jin, V.L. and Kay, A. and Kirkman, K.P. and Klein, J.A. and Knops, J.M.H. and Kimberly J. La Pierre and L. Ladwig and Lambrinos, J.G. and Leakey, A.D.B. and Li, Q. and Li, W. and McCulley, R. and Melbourne, B. and Mitchell, C.E. and Joslin L. Moore and J.W. Morgan and Mortensen, B. and O{\textquoteright}Halloran, L.R. and P{\"a}rtel, M. and Pascual, J and Pyke, D.A. and A. Risch and Salguero-Gomez, R. and Sankaran, M. and Schuetz, M. and Simonsen, A. and M.D. Smith and Stevens, C. and Sullivan, L. and Wardle, G.M. and Wolkovich, E.M. and Wragg, P.D. and Wright, J. and Yang, L.} } @article {KNZ001511, title = {Dissolved organic matter in headwater streams: compositional variability across climatic regions of North America}, journal = {Geochimica et Cosmochimica Acta}, volume = {94}, year = {2012}, pages = {95 -108}, abstract = {

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

}, keywords = {LTER-KNZ}, doi = {10.1016/j.gca.2012.06.031}, url = {https://www.sciencedirect.com/science/article/pii/S0016703712004097?via\%3Dihub}, author = {Jaff{\'e}, R. and Yamashita, Y. and Maie, N. and Cooper, W.T. and Dittmar, T. and W. K. Dodds and Jones, J.B. and Myoshi, T. and Ortiz-Zayas, J.R. and Podgorski, D.C. and Watanabe, A.} } @article {KNZ001520, title = {High levels of relatedness between Brown-headed Cowbird (Molothrus ater) nestmates in a heavily parasitized host community}, journal = {The Auk}, volume = {129}, year = {2012}, pages = {623 -631}, abstract = {

Multiple parasitism of host nests by generalist brood parasites reflects the decisions of laying females and may influence the development and behavior of parasitic young. We used microsatellite and mtDNA control-region haplotype data to examine the relatedness of Brown-headed Cowbird (Molothrus ater) offspring in multiply parasitized nests sampled from a heavily parasitized host community in northeastern Kansas. We also examined how host nest availability influenced the degree of multiple parasitism, and used community-wide parasitism data to explore whether female cowbirds were constrained in their laying decisions. Relatedness estimates for all suitable pairwise comparisons (n = 94 from 41 multiply parasitized nests) found that the mean likelihood than an individual cowbird in a multiply parasitized nest shared its nest with a full sibling was 40.4\% (95\% confidence interval: 28.4\–52.4\%), indicating that many cowbird offspring were reared with full siblings. Extensive community-wide parasitism data revealed that most cowbird offspring shared the nest with \≥1 other conspecific. Additionally, we found that the proportion of available host nests increased steeply at the start of the breeding season and remained high for most of the breeding season, but that the degree of multiple parasitism was unrelated to the number of new nests. We found evidence that laying decisions of female cowbirds were constrained, which suggests that heavy parasitism levels were due to a high degree of competition for host nests. This intense competition for host nests, in turn, results in cowbird offspring often competing with conspecifics in our population, including full siblings, for host parental care.

}, keywords = {LTER-KNZ, brown-headed cowbird, generalist brood parasite, kinship, laying pattern, Molothrus ater, nestmate relatedness}, doi = {10.1525/auk.2012.11236}, url = {https://academic.oup.com/auk/article/129/4/623/5149419}, author = {Rivers, J.W. and Young, S. and Gonzalez, E.G. and Horton, B. and Lock, J. and Fleisher, R.C.} } @booklet {KNZ001539, title = {Long-term trends in ecological systems: a basis for understanding responses to global change. USDA Agriculture Research Service Publication, Technical Bulletin 1931. Washington, D.C}, year = {2012}, abstract = {

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

}, keywords = {LTER-KNZ, atmospheric chemistry, Climate change, cross-site comparisons, disturbance, ecological response, ecology, ecosystem, EcoTrends, experimental forests, global change, human demography, human population growth, Long Term Ecological Research (LTER), long-term datasets, Precipitation, rangeland, rangeland research stations, surface water chemistry}, author = {Peters, D.P.C. and Laney, C.M. and Lugo, A.E. and Scott. L. Collins and Driscoll, C.T. and Groffman, P.M. and Grove, J.M. and Alan K. Knapp and Kratz, T.K. and Ohman, M.D. and Waide, R.B. and Yao, J.} } @article {KNZ001392, title = {Complexity in climate change impacts: An analytical framework for effects mediated by plant disease}, journal = {Plant Pathology}, volume = {60}, year = {2011}, pages = {15 -30}, abstract = {

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

}, keywords = {LTER-KNZ, cereal head blight, disease risk, ecosystem services, fusarium graminearum, phytophthora infestans, potato late blight}, doi = {10.1111/j.1365-3059.2010.02409.x}, url = {https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-3059.2010.02409.x}, author = {Garrett, K.A. and Forbes, G.A. and Savary, S. and Skelsey, P. and Sparks, A.H. and Valdivia, C. and van Bruggen, A.H.C. and Willocquet, L. and Djurle, A. and Duveiller, E. and Eckersten, H. and Pande, S. and Vera Cruz, C. and Yuen, J.} } @article {KNZ001411, title = {Explaining temporal variation in above-ground productivity in a mesic grassland: the role of climate and flowering}, journal = {Journal of Ecology}, volume = {99}, year = {2011}, pages = {1250 -1262}, abstract = {

1. Annual above-ground net primary productivity (ANPP) in mesic grasslands is known to be highly temporally variable. While yearly precipitation or average yearly temperature can explain some of this temporal variability, much of the variation in ANPP remains unexplained. 2. Here we address the heretofore unexplained variation in 25 years of productivity data from a mesic grassland at Konza Prairie (north-eastern Kansas) by examining the effects of precipitation and temperature during periods relevant to the phenology and growth cycle of the dominant C4 grasses and the flowering stalk production of these species. We assessed both the direct effects and indirect effects via flowering of phenologically relevant climate periods on ANPP using structural equation modelling (SEM). 3. We found ANPP to be strongly positively influenced by flowering stalk production of the dominant C4 grasses, precipitation during periods relevant to vegetative growth (15 April\–14 July) and flowering stalk elongation (15 July\–14 August) of the dominant grasses, and fire. In addition, flowering stalk production was negatively influenced by high temperatures during the flowering stalk elongation period, which therefore resulted in a negative indirect effect on ANPP. We found little evidence for the effects of the previous year\’s total annual precipitation or mean annual temperature on ANPP. 4. By including flowering stalk production and separating climate variables into phenologically relevant periods we were able to increase the percentage of observed variance in ANPP explained by six models, relating to different topographic positions and burn regimes, from an average of 22\% to 48\%, with the best model explaining 61\% of variation in ANPP. 5.Synthesis. The link between climatic periods relevant to the phenology and growth of dominant C4 grasses, flowering stalk production of these grasses and ANPP shown here improves our ability to predict productivity in mesic grasslands, an ecologically and economically important ecosystem.

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1365-2745.2011.01844.x}, url = {https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2745.2011.01844.x}, author = {Kimberly J. La Pierre and Yuan, S.H. and Chang, C.C. and M.L. Avolio and Hallett, L.M. and Schreck, T. and M.D. Smith} } @article {KNZ001427, title = {From precipitation to groundwater baseflow in a native prairie ecosystem: a regional study of the Konza LTER in the Flint Hills of Kansas, USA}, journal = {Hydrology and Earth System Sciences}, volume = {15}, year = {2011}, pages = {3181 -3194}, abstract = {

Methods are developed to study hydrologic interactions across the surficial/groundwater interface in a native prairie ecosystem. Surficial ecohydrologic processes are simulated with the USDA\&$\#$39;s EPIC model using daily climate data from the Kansas Weather Data Library, vegetation and soil data from the USDA, and current land-use management practices. Results show that mean annual precipitation (from 1985\–2005) is partitioned into 13\% runoff regionally and 14\% locally over the Konza LTER, lateral flow through soil is 1\% regionally and 2\% locally, groundwater recharge is 11\% regionally and 9\% locally, and evapotranspiration accounts for the remaining 75\%. The spatial distribution of recharge was used in a regional Modflow groundwater model that was calibrated to existing groundwater observations and field measurements gathered for this study, giving a hydraulic conductivity in the Flint Hills region of 1\–2 m day\−1 with a local zone (identified here) of 0.05\–0.1 m day\−1. The resistance was set to fixed representative values during model calibration of hydraulic conductivity, and simple log-log relations correlate the enhanced recharge beneath ephemeral upland streams and baseflow in perennial lowland streams to the unknown resistance of the streambeds. Enhanced recharge due to stream transmission loss (the difference between terrestrial runoff and streamflow) represents a small fraction of streamflow in the ephemeral upland and the resistance of this streambed is 100 000 day. Long-term baseflow in the local Kings Creek watershed (2\% of the groundwater recharge over the watershed) is met when the resistance of the lowland streambed is 1000 day. The coupled framework developed here to study surficial ecohydrological processes using EPIC and groundwater hydrogeological processes using Modflow provides a baseline hydrologic assessment and a computational platform for future investigations to examine the impacts of climate change, vegetative cover, soils, and management practices on hydrologic forcings.

}, keywords = {LTER-KNZ}, doi = {10.5194/hess-15-3181-2011}, url = {https://www.hydrol-earth-syst-sci.net/15/3181/2011/}, author = {Steward, D.R. and Yang, X. and Lauwo, S.Y. and Staggenborg, S.A. and G. L. Macpherson and Welch, S.M.} } @article {KNZ001437, title = {Land fragmentation under rapid urbanization: A cross-site analysis of Southwestern cities}, journal = {Urban Ecosystems}, volume = {14}, year = {2011}, pages = {429 -455}, abstract = {

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

}, keywords = {LTER-KNZ, Exurbanization, Land fragmentation, The US Southwest, Urban ecology}, doi = {10.1007/s11252-011-0157-8}, url = {https://link.springer.com/article/10.1007\%2Fs11252-011-0157-8}, author = {York, A.M. and Shrestha, M. and Boone, C.G. and Zhang, S. and J. A. Harrington and Prebyl, T.J. and Swann, A. and Agar, M. and Antolin, M.F. and Nolen, B. and Wright, J.B. and Skaggs, R.} } @article {KNZ001419, title = {Data model for system conceptualization in groundwater studies}, journal = {International Journal of Geographical Information Science}, volume = {24}, year = {2010}, pages = {677 -694}, abstract = {

Development of a conceptualization of a hydrogeologic system serves as the basis of groundwater modeling. While existing groundwater data models are designed to store groundwater system information, none is designed to capture its conceptual view. This study addresses this need by presenting a new object-oriented Conceptualization Groundwater Data Model that represents a groundwater system as a series of aquifer layers with defined aquifer properties and water boundary conditions. A case study is presented that develops the conceptual view of the groundwater system beneath Konza Prairie. This single conceptualization is used to support groundwater models across existing technologies of finite difference, finite element, and analytical element methods. While the models each employ different mathematics, data input files, and formats, all models are founded on the same conceptualization process that is represented using this new data model. The case study illustrates the data model\&$\#$39;s promise as an effective mechanism for groundwater system conceptualization and data storage, and utility for various groundwater computational models. This conceptualization of a groundwater data model suggests a new focus on incorporating system conceptualization into data model design.

}, keywords = {LTER-KNZ, conceptualization, data model, groundwater, simulation}, doi = {10.1080/13658810902967389}, url = {https://www.tandfonline.com/doi/abs/10.1080/13658810902967389}, author = {Yang, X. and Steward, D.R. and de Langeb, W.J. and Lauwoa, S.Y. and Chubb, R.M. and Bernard, E.A.} } @article {KNZ001278, title = {Massively parallel 454-sequencing of fungal communities in Quercus spp. ectomycorrhizas indicates seasonal dynamics in urban and rural sites}, journal = {Molecular Ecology}, volume = {19}, year = {2010}, pages = {41 -53}, abstract = {We analysed two sites within and outside an urban development in a rural background to estimate the fungal richness, diversity and community composition in Quercus spp. ectomycorrhizas using massively parallel 454-sequencing in combination with DNA-tagging. Our analyses indicated that shallow sequencing (\~{}150 sequences) of a large number of samples (192 in total) provided data that allowed identification of seasonal trends within the fungal communities: putative root-associated antagonists and saprobes that were abundant early in the growing season were replaced by common ectomycorrhizal fungi in the course of the growing season. Ordination analyses identified a number of factors that were correlated with the observed communities including host species as well as soil organic matter, nutrient and heavy metal enrichment. Overall, our application of the high throughput 454 sequencing provided an expedient means for characterization of fungal communities.}, keywords = {LTER-KNZ}, doi = {10.1111/j.1365-294X.2009.04483.x}, author = {A. Jumpponen and Jones, K.L. and Mattox, J.D. and Yeage, C.} } @article {KNZ001149, title = {Shrub encroachment in North American grasslands: Shifts in growth form dominance rapidly alters control of ecosystem carbon inputs}, journal = {Global Change Biology}, volume = {14}, year = {2008}, pages = {615 -623}, abstract = {

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

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1365-2486.2007.01512.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2486.2007.01512.x}, author = {Alan K. Knapp and J. M. Briggs and Scott. L. Collins and S.R. Archer and Bret-Harte, M.S. and Ewers, B.E. and Peters, D.P. and Young, D.R. and Shaver, G.R. and Pendall, E. and Cleary, M.B.} } @article {KNZ001016, title = {A comparison of the species-timerelationship across ecosystems and taxonomic groups}, journal = {Oikos}, volume = {112}, year = {2006}, pages = {185 -195}, abstract = {The species{\textendash}time relationship (STR) describes how the species richness of a community increases with the time span over which the community is observed. This pattern has numerous implications for both theory and conservation in much the same way as the species{\textendash}area relationship (SAR). However, the STR has received much less attention and to date only a handful of papers have been published on the pattern. Here we gather together 984 community time-series, representing 15 study areas and nine taxonomic groups, and evaluate their STRs in order to assess the generality of the STR, its consistency across ecosystems and taxonomic groups, its functional form, and its relationship to local species richness. In general, STRs were surprisingly similar across major taxonomic groups and ecosystem types. STRs tended to be well fit by both power and logarithmic functions, and power function exponents typically ranged between 0.2 and 0.4. Communities with high richness tended to have lower STR exponents, suggesting that factors increasing richness may simultaneously decrease turnover in ecological systems. Our results suggest that the STR is as fundamental an ecological pattern as the SAR, and raise questions about the general processes underlying this pattern. They also highlight the dynamic nature of most species assemblages, and the need to incorporate time scale in both basic and applied research on species richness patterns.}, keywords = {LTER-KNZ}, doi = {10.1111/j.0030-1299.2006.14223.x}, author = {White, E.P. and P. Adler and Lauenroth, W.K. and Gill, R.A. and Greenberg, D. and Kaufman, D.M. and Rassweiler, A. and Rusak, J.A. and M. A. Smith and Steinbeck, J. and Waide, R.B. and Yao, J.} } @article {KNZ001150, title = {Comparisons of land cover and LAI estimates derived from ETM+ and MODIS for four sites in North America: a quality assessment of 2000/2001 provisional MODIS products}, journal = {Remote Sensing of Environment}, volume = {88}, year = {2003}, pages = {221 -362}, abstract = {The MODIS land science team produces a number of standard products, including land cover and leaf area index (LAI). Critical to the success of MODIS and other sensor products is an independent evaluation of product quality. In that context, we describe a study using field data and Landsat ETM+ to map land cover and LAI at four 49-km2 sites in North America containing agricultural cropland (AGRO), prairie grassland (KONZ), boreal needleleaf forest, and temperate mixed forest. The purpose was to: (1) develop accurate maps of land cover, based on the MODIS IGBP (International Geosphere{\textendash}Biosphere Programme) land cover classification scheme; (2) derive continuous surfaces of LAI that capture the mean and variability of the LAI field measurements; and (3) conduct initial MODIS validation exercises to assess the quality of early (i.e., provisional) MODIS products. ETM+ land cover maps varied in overall accuracy from 81\% to 95\%. The boreal forest was the most spatially complex, had the greatest number of classes, and the lowest accuracy. The intensive agricultural cropland had the simplest spatial structure, the least number of classes, and the highest overall accuracy. At each site, mapped LAI patterns generally followed patterns of land cover across the site. Predicted versus observed LAI indicated a high degree of correspondence between field-based measures and ETM+ predictions of LAI. Direct comparisons of ETM+ land cover maps with Collection 3 MODIS cover maps revealed several important distinctions and similarities. One obvious difference was associated with image/map resolution. ETM+ captured much of the spatial complexity of land cover at the sites. In contrast, the relatively coarse resolution of MODIS did not allow for that level of spatial detail. Over the extent of all sites, the greatest difference was an overprediction by MODIS of evergreen needleleaf forest cover at the boreal forest site, which consisted largely of open shrubland, woody savanna, and savanna. At the agricultural, temperate mixed forest, and prairie grassland sites, ETM+ and MODIS cover estimates were similar. Collection 3 MODIS-based LAI estimates were considerably higher (up to 4 m2 m-2) than those based on ETM+ LAI at each site. There are numerous probable reasons for this, the most important being the algorithms{\textquoteright} sensitivity to MODIS reflectance calibration, its use of a prelaunch AVHRR-based land cover map, and its apparent reliance on mainly red and near-IR reflectance. Samples of Collection 4 LAI products were examined and found to consist of significantly improved LAI predictions for KONZ, and to some extent for AGRO, but not for the other two sites. In this study, we demonstrate that MODIS reflectance data are highly correlated with LAI across three study sites, with relationships increasing in strength from 500 to 1000 m spatial resolution, when shortwave-infrared bands are included.}, keywords = {LTER-KNZ, BigFoot, ETM, IGBP, Land cover, Leaf area index, MODIS, Validation}, doi = {10.1016/j.rse.2003.06.006}, author = {Cohen, W.B. and Maiersperger, T.K. and Yang, Z. and Gower, S.T. and Turner, D.P. and Ritts, W.D. and Berterretche, M. and Running, S.W.} } @article {KNZ00670, title = {Aspects of methane flow from sediment through emergent cattail (Typha latifolia) plants}, journal = {New Phytologist}, volume = {139}, year = {1998}, pages = {495 -503}, abstract = {We measured the flow of methane in Typha latifolia L. (cattail)-dominated wetlands from microbial production in anoxic sediment into, through, and out of emergent T. latifolia shoots (i.e. plant transport). The purpose was to identify key environmental and plant factors that might affect rates of methane efflux from wetlands to the Earth{\textquoteright}s atmosphere. Methane accumulated in leafy T. latifolia shoots overnight, reaching concentrations up to 10000 μl l-1 (vs. atmospheric concentrations <4 μl l-1), suggesting that lower stomatal conductance at night limits methane efflux from the plant into ambient air. Daytime light and (or) lower atmospheric humidity that induce convective gas flow through the plant coincided with (a) an increase in the rate of methane efflux from T. latifolia leaves to ambient air (from <0{\textperiodcentered}1 to >2{\textperiodcentered}0 μmol m-2 (leaf) s-1) and (b) a decrease in shoot methane concentration to <70 μl l-1. Very short fluctuation in stomatal conductance during the day did not affect the methane efflux rate unless, possibly, the rate of photosynthesis decreased. A strong relationship between the maximum daily rate of methane efflux and shoot methane concentration (measured before the onset of convective gas flow) suggests T. latifolia plants behave like a capacitor (filling with methane at night, emitting the stored methane during the day). Experimentally cutting leaves (to prevent pressurization) reduced plant capacitance for methane.}, keywords = {LTER-KNZ}, doi = {10.1046/j.1469-8137.1998.00210.x}, author = {Yavitt, J.B. and Alan K. Knapp} } @article {KNZ00532, title = {Biological properties of soil and subsurface sediments under abandoned pasture and cropland}, journal = {Soil Biology \& Biochemistry}, volume = {28}, year = {1996}, pages = {837 -846}, abstract = {Little is known about the effects of most surface land-use practices on shallow subsurface microbial communities. We analyzed duplicate cores taken aseptically from up to 10 m depth from unconsolidated valley sediments (soils) beneath an abandoned pasture reverting to tall grass prairie and cropland. Both profiles had similar soil texture, with moderately higher silt under cropland and a slight decrease in clay with depth. Soluble organic C was about two times higher in the grassland site and dissolved O2 was about 8\% lower compared with the cropland site. Water content and C-to-N ratios were greatest at the grassland surface but were less in the grassland than the cropland site within 2 m depth. In general, numbers of aerobic heterotrophic bacteria and protozoa decreased with depth until the saturated zone (4.3 m in grassland and 5.3 m in the cropland site). Bacterial numbers as determined by plate counts were about 10-fold less at the groundwater interface than in the surface soils at both sites. Direct microscopic counts of total bacteria were approximately the same in the surface soil and the sediments at the top of the water table at both sites. The top of the water table generally did not exhibit elevated microbial biomass or activity relative to deeper sediments. There was no significant relationship between protozoan numbers and microbial thymidine uptake at the cropland site, but a negative relationship was observed at the grassland site. The data suggest that cultivation may affect microbial biomass and activity in the subsurface, as well as community interactions between protozoa and bacteria.}, keywords = {LTER-KNZ}, doi = {10.1016/0038-0717(96)00057-0}, author = {W. K. Dodds and Banks, M.K. and Clenan, C.S. and C. W. Rice and Sotomayor, D. and Strauss, E.A. and Yu, W.} } @inbook {KNZ00508, title = {Comparison of spatial and temporal variability of ecological parameters from 12 North American ecosystems}, booktitle = {Evaluating And Monitoring The Health Of Large-Scale Ecosystems, NATO ASI series, Vol I 28}, year = {1995}, pages = {359 -383}, publisher = {Springer-Verlag}, organization = {Springer-Verlag}, address = {Berlin}, keywords = {LTER-KNZ}, author = {Kratz, T.K. and Magnuson, J.J. and Bayley, P. and Benson, B.J. and Berish, C.W. and Bledsoe, C.S. and Blood, E.R. and Bowser, C.J. and Carpenter, S.R. and Cunningham, G.L. and Dahlgren, R. and Frost, T.M. and Halfpenny, J.C. and Hansen, J. and Heisey, D. and Inouye, R.S. and D.W. Kaufman and McKee, A. and Yarie, J.A.}, editor = {Rapport, D.J. and Gaudet, C.L. and Calow, P.} } @article {KNZ00507, title = {Gas exchange characteristics of Typha latifolia L. from nine sites across North America}, journal = {Aquatic Biology}, volume = {49}, year = {1995}, pages = {203 -215}, abstract = {Gas exchange characteristics were measured in the field for nine populations of Typha latifolia L. from Florida to Minnesota in North America. These populations spanned a substantial gradient in growing season length and environmental conditions. The purpose of this study was to assess geographic variability in stomatal conductance (gst) in T. latifolia populations, as well as to identify key environmental and plant factors that may affect gst and, potentially, trace gas emissions through stomata. Midday rates of net photosynthesis (A) and gst were measured under full sunlight conditions at each site, and more intensive measurements of diurnal and seasonal variability were made at selected sites. In general, A varied less than gst (1.5 vs. 3 fold) among sites with maximum A (27.4 μmol m-2 s-1) and gst (1076.7 mmol m-2 s-1) measured at the southern sites. We found that A and gst in T. latifolia increased significantly with increasing temperature and light level, and varied diurnally and seasonally. Moreover, stomata closed completely at night, in contrast to some other wetland plants. Both A and gst also increased significantly along the length of leaves from the base of plants to the upper canopy. Finally, although gst was quite variable, A did not appear to be limited by gst under typical field conditions. It was concluded that generalizations that stomata in wetland plants are relatively unresponsive to environmental factors are not consistent with field responses measured in T. latifolia. As a result, because gst may influence trace gas flux in this species, spatial and temporal variations in gst need to be considered when emissions are estimated.}, keywords = {LTER-KNZ}, doi = {10.1016/0304-3770(94)00433-M}, author = {Alan K. Knapp and Yavitt, J.B.} } @article {KNZ00525, title = {Methane emissions to the atmosphere through emergent cattail (Typha latifolia L.) plants}, journal = {Tellus}, volume = {47}, year = {1995}, pages = {521 -534}, keywords = {LTER-KNZ}, doi = {10.3402/tellusb.v47i5.16065}, author = {Yavitt, J.B. and Alan K. Knapp} } @article {KNZ00526, title = {Optimal staining and sample storage time for direct microscopic enumeration of total and active bacteria in soil with two fluorescent dyes}, journal = {Applied and Environmental Microbiology}, volume = {61}, year = {1995}, pages = {3367 -3372}, abstract = {Direct counting techniques, first developed for aquatic samples, can be used to enumerate bacteria in soil and groundwater sediments. Two fluorescent dyes, 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) for actively respiring bacteria and 4(prm1),6-diamidino-2-phenylindole (DAPI) for total bacteria, were tested for their usefulness in epifluorescent direct bacterial enumeration in soil. Both dyes can be used for the same soil sample without affecting enumeration results. Staining for 8 h with CTC and for 40 min with DAPI resulted in maximum numbers of stained cells. The optimal DAPI staining concentration is 10 mg liter(sup-1). After preparation, slides should be stored at 4(deg)C and counted within 2 days for CTC and within 24 h for DAPI. Sodium PP(infi) or sodium chloride solutions were used to desorb bacteria from soil prior to counting. Counts were significantly higher when sodium chloride was used.}, keywords = {LTER-KNZ}, url = {http://aem.asm.org/content/61/9/3367.short}, author = {Yu, W. and W. K. Dodds and Banks, M.K. and Skalsky, J. and Strauss, E.A.} } @proceedings {KNZ00524, title = {Wetlands may change tallgrass prairie from a sink to a source for atmospheric methane}, year = {1995}, pages = {137 -141}, keywords = {LTER-KNZ, tallgrass prairie}, url = {http://images.library.wisc.edu/EcoNatRes/EFacs/NAPC/NAPC14/reference/econatres.napc14.jyavitt.pdf}, author = {Yavitt, J.B. and Alan K. Knapp}, editor = {D.C. Hartnett} } @article {KNZ00368, title = {Evaluation of the closed-chamber method for estimating methane emissions from aquatic plants}, journal = {Tellus}, volume = {44B}, year = {1992}, pages = {63 -71}, abstract = {

Closed flow chambers are commonly used to measure CH4 emissions from aquatic plants. We monitored environmental and plant physiological responses to closed chambers during measurements of CH4 emission from Typha latifolia (cattails) to evaluate potential errors in emission estimates. In 1990, two wetlands were studied: one in NE Kansas and one in central New York. Leaves and stems of Typha enclosed in gas-impermable, collapsible bags were exposed to rapid increases in chamber air temperature and, thus, tissue temperatures (up to 9oC above ambient) as well as rapid reductions in both CO2 partial pressure due to photosynthesis and the leaf-to-air water vapor pressure deficit due to transpiration. These rapid (\< 5 min) environmental changes within chambers are known to affect stomatal aperture through which CH4 exists Typha leaves. Indeed, stomatal conductance (g) increased up to 42\% compared to control leaves after 19 min of enclosure in chambers, and chamber effects on interactions between irradiance and g were detected. The duration of enclosure also critically affected the CH4 gradient within chambers. Estimated CH4 emission from leaves in chambers sampled after 19 min (3 nmol m-2s-1) was 10-fold lower than estimates based on 30-s sampling periods (30 nmol m-2s-1) due to reduction in the leaf-to-air concentration gradient for CH4. Since closed chambers 1)induce alterations in g, 2)may result in rapid environmental changes, and 3)lead to almost instantaneous reductions in leaf-to-air concentration gradient for CH4 diffusion, we suggest that only very short enclosure times should be used when measuring CH4 emission from plants

}, keywords = {LTER-KNZ}, doi = {10.1034/j.1600-0889.1992.00006.x}, author = {Alan K. Knapp and Yavitt, J.B.} } @article {KNZ00310, title = {Regional analysis of the central Great Plains}, journal = {BioScience}, volume = {41}, year = {1991}, pages = {685 -692}, keywords = {LTER-KNZ}, doi = {http://www.jstor.org/stable/1311763}, author = {Burke, I.C. and Kittel, T.G.F. and Lauenroth, W.K. and Snook, P. and Yonker, C.M. and Parton, W.J.} } @article {KNZ00297, title = {Separability of soils in a tallgrass prairie using SPOT and DEM Data}, journal = {Remote Sensing of the Environment}, volume = {32}, year = {1990}, pages = {10 -17}, abstract = {

A sufficient transformation technique is important in using computer-aided soil pattern recognition to interpret soils in soil surveys. This study was conducted using the Systeme Probatoire d\&$\#$39;Observation de la Terre (SPOT) satellite images and Digital Elevation Model (DEM) data to seperate five major sils in a tallgrass prairie near Manhattan, Kansas. The high resolution SPOT satellite im;ages were integrated with DEM data. the soils were sampled and classified using conventional soil survey procedures to extract the important soil features from SPOT and DEM data. A pairwise transformed divergence analysis was also conducted to evaluate the several aanonical variables in order to sufficiently separate the soils. Consequently, two canonical variables derived from training samples were selected. Our results suggest that canonically transformed data were superior to combined SPOT and DEM data. High resolution SPOT images and DEM data can be used to aid secondd- order soil surveys in grasslands

}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.1016/0034-4257(90)90027-J}, author = {Su, H. and Kanemasu, E.T. and Ransom, M.D. and Yang, S.} }