@article {115013, title = {Richness, not evenness, varies across water availability gradients in grassy biomes on five continents.}, journal = {Oecologia}, volume = {199}, year = {2022}, month = {2022 Jul}, pages = {649-659}, abstract = {

We sought to understand the role that water availability (expressed as an aridity index) plays in determining regional and global patterns of richness and evenness, and in turn how these water availability-diversity relationships may result in different richness-evenness relationships at regional and global scales. We examined relationships between water availability, richness and evenness for eight grassy biomes spanning broad water availability gradients on five continents. Our study found that relationships between richness and water availability switched from positive for drier (South Africa, Tibet and USA) vs. negative for wetter (India) biomes, though were not significant for the remaining biomes. In contrast, only the India biome showed a significant relationship between water availability and evenness, which was negative. Globally, the richness-water availability relationship was hump-shaped, however, not significant for evenness. At the regional scale, a positive richness-evenness relationship was found for grassy biomes in India and Inner Mongolia, China. In contrast, this relationship was weakly concave-up globally. These results suggest that different, independent factors are determining patterns of species richness and evenness in grassy biomes, resulting in differing richness-evenness relationships at regional and global scales. As a consequence, richness and evenness may respond very differently across spatial gradients to anthropogenic changes, such as climate change.

}, keywords = {Biodiversity, China, Ecosystem, Poaceae, Water}, issn = {1432-1939}, doi = {10.1007/s00442-022-05208-6}, author = {Smith, Melinda D and Koerner, Sally E and Avolio, Meghan L and Komatsu, Kimberly J and Eby, Stephanie and Forrestel, Elisabeth J and Collins, Scott L and Wilcox, Kevin R and Ahumada, Rodrigo and Morgan, John W and Oliva, Gabriel and O{\~n}atibia, Gast{\'o}n R and Overbeck, Gerhard E and Peter, Guadalupe and Quiroga, Emiliano and Sankaran, Mahesh and Wu, Jianshuang and Yahdjian, Laura and Yu, Qiang} } @article {105155, title = {Opposing community assembly patterns for dominant and nondominant plant species in herbaceous ecosystems globally.}, journal = {Ecol Evol}, volume = {11}, year = {2021}, month = {2021 Dec}, pages = {17744-17761}, abstract = {

Biotic and abiotic factors interact with dominant plants-the locally most frequent or with the largest coverage-and nondominant plants differently, partially because dominant plants modify the environment where nondominant plants grow. For instance, if dominant plants compete strongly, they will deplete most resources, forcing nondominant plants into a narrower niche space. Conversely, if dominant plants are constrained by the environment, they might not exhaust available resources but instead may ameliorate environmental stressors that usually limit nondominants. Hence, the nature of interactions among nondominant species could be modified by dominant species. Furthermore, these differences could translate into a disparity in the phylogenetic relatedness among dominants compared to the relatedness among nondominants. By estimating phylogenetic dispersion in 78\ grasslands across five continents, we found that dominant species were clustered (e.g., co-dominant grasses), suggesting dominant species are likely organized by environmental filtering, and that nondominant species were either randomly assembled or overdispersed. Traits showed similar trends for those sites (\<50\%) with sufficient trait data. Furthermore, several lineages scattered in the phylogeny had more nondominant species than expected at random, suggesting that traits common in nondominants are phylogenetically conserved and have evolved multiple times. We also explored environmental drivers of the dominant/nondominant disparity. We found different assembly patterns for dominants and nondominants, consistent with asymmetries in assembly mechanisms. Among the different postulated mechanisms, our results suggest two complementary hypotheses seldom explored: (1) Nondominant species include lineages adapted to thrive in the environment generated by dominant species. (2) Even when dominant species reduce resources to nondominant ones, dominant species could have a stronger positive effect on some nondominants by ameliorating environmental stressors affecting them, than by depleting resources and increasing the environmental stress to those nondominants. These results show that the dominant/nondominant asymmetry has ecological and evolutionary consequences fundamental to understand plant communities.

}, issn = {2045-7758}, doi = {10.1002/ece3.8266}, author = {Arnillas, Carlos Alberto and Borer, Elizabeth T and Seabloom, Eric W and Alberti, Juan and B{\'a}ez, Selene and Bakker, Jonathan D and Boughton, Elizabeth H and Buckley, Yvonne M and Bugalho, Miguel Nuno and Donohue, Ian and Dwyer, John and Firn, Jennifer and Gridzak, Riley and Hagenah, Nicole and Hautier, Yann and Helm, Aveliina and Jentsch, Anke and Knops, Johannes M H and Komatsu, Kimberly J and Laanisto, Lauri and Laungani, Ramesh and McCulley, Rebecca and Moore, Joslin L and Morgan, John W and Peri, Pablo Luis and Power, Sally A and Price, Jodi and Sankaran, Mahesh and Schamp, Brandon and Speziale, Karina and Standish, Rachel and Virtanen, Risto and Cadotte, Marc W} } @article {84576, title = {General destabilizing effects of eutrophication on grassland productivity at multiple spatial scales.}, journal = {Nat Commun}, volume = {11}, year = {2020}, month = {2020 10 23}, pages = {5375}, abstract = {

Eutrophication is a widespread environmental change that usually reduces the stabilizing effect of plant diversity on productivity in local communities. Whether this effect is scale dependent remains to be elucidated. Here, we determine the relationship between plant diversity and temporal stability of productivity for 243 plant communities from 42 grasslands across the globe and quantify the effect of chronic fertilization on these relationships. Unfertilized local communities with more plant species exhibit greater asynchronous dynamics among species in response to natural environmental fluctuations, resulting in greater local stability (alpha stability). Moreover, neighborhood communities that have greater spatial variation in plant species composition within sites (higher beta diversity) have greater spatial asynchrony of productivity among communities, resulting in greater stability at the larger scale (gamma stability). Importantly, fertilization consistently weakens the contribution of plant diversity to both of these stabilizing mechanisms, thus diminishing the positive effect of biodiversity on stability at differing spatial scales. Our findings suggest that preserving grassland functional stability requires conservation of plant diversity within and among ecological communities.

}, issn = {2041-1723}, doi = {10.1038/s41467-020-19252-4}, author = {Hautier, Yann and Zhang, Pengfei and Loreau, Michel and Wilcox, Kevin R and Seabloom, Eric W and Borer, Elizabeth T and Byrnes, Jarrett E K and Koerner, Sally E and Komatsu, Kimberly J and Lefcheck, Jonathan S and Hector, Andy and Adler, Peter B and Alberti, Juan and Arnillas, Carlos A and Bakker, Jonathan D and Brudvig, Lars A and Bugalho, Miguel N and Cadotte, Marc and Caldeira, Maria C and Carroll, Oliver and Crawley, Mick and Collins, Scott L and Daleo, Pedro and Dee, Laura E and Eisenhauer, Nico and Eskelinen, Anu and Fay, Philip A and Gilbert, Benjamin and Hansar, Amandine and Isbell, Forest and Knops, Johannes M H and MacDougall, Andrew S and McCulley, Rebecca L and Moore, Joslin L and Morgan, John W and Mori, Akira S and Peri, Pablo L and Pos, Edwin T and Power, Sally A and Price, Jodi N and Reich, Peter B and Risch, Anita C and Roscher, Christiane and Sankaran, Mahesh and Sch{\"u}tz, Martin and Smith, Melinda and Stevens, Carly and Tognetti, Pedro M and Virtanen, Risto and Wardle, Glenda M and Wilfahrt, Peter A and Wang, Shaopeng} } @article {45930, title = {Change in dominance determines herbivore effects on plant biodiversity.}, journal = {Nat Ecol Evol}, year = {2018}, month = {2018 Oct 29}, abstract = {

Herbivores alter plant biodiversity (species richness) in many of the world{\textquoteright}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.

}, issn = {2397-334X}, doi = {10.1038/s41559-018-0696-y}, author = {Koerner, Sally E and Smith, Melinda D and Burkepile, Deron E and Hanan, Niall P and Avolio, Meghan L and Collins, Scott L and Knapp, Alan K and Lemoine, Nathan P and Forrestel, Elisabeth J and Eby, Stephanie and Thompson, Dave I and Aguado-Santacruz, Gerardo A and Anderson, John P and Anderson, T Michael and Angassa, Ayana and Bagchi, Sumanta and Bakker, Elisabeth S and Bastin, Gary and Baur, Lauren E and Beard, Karen H and Beever, Erik A and Bohlen, Patrick J and Boughton, Elizabeth H and Canestro, Don and Cesa, Ariela and Chaneton, Enrique and Cheng, Jimin and D{\textquoteright}Antonio, Carla M and Deleglise, Claire and Demb{\'e}l{\'e}, Fadiala and Dorrough, Josh and Eldridge, David J and Fernandez-Going, Barbara and Fern{\'a}ndez-Lugo, Silvia and Fraser, Lauchlan H and Freedman, Bill and Garc{\'\i}a-Salgado, Gonzalo and Goheen, Jacob R and Guo, Liang and Husheer, Sean and Karemb{\'e}, Moussa and Knops, Johannes M H and Kraaij, Tineke and Kulmatiski, Andrew and Kyt{\"o}viita, Minna-Maarit and Lezama, Felipe and Loucougaray, Gregory and Loydi, Alejandro and Milchunas, Dan G and Milton, Suzanne J and Morgan, John W and Moxham, Claire and Nehring, Kyle C and Olff, Han and Palmer, Todd M and Rebollo, Salvador and Riginos, Corinna and Risch, Anita C and Rueda, Marta and Sankaran, Mahesh and Sasaki, Takehiro and Schoenecker, Kathryn A and Schultz, Nick L and Sch{\"u}tz, Martin and Schwabe, Angelika and Siebert, Frances and Smit, Christian and Stahlheber, Karen A and Storm, Christian and Strong, Dustin J and Su, Jishuai and Tiruvaimozhi, Yadugiri V and Tyler, Claudia and Val, James and Vandegehuchte, Martijn L and Veblen, Kari E and Vermeire, Lance T and Ward, David and Wu, Jianshuang and Young, Truman P and Yu, Qiang and Zelikova, Tamara Jane} } @article {27277, title = {Local loss and spatial homogenization of plant diversity reduce ecosystem multifunctionality.}, journal = {Nat Ecol Evol}, volume = {2}, year = {2018}, month = {2017 Dec 04}, 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.

}, issn = {2397-334X}, doi = {10.1038/s41559-017-0395-0}, author = {Hautier, Yann and Isbell, Forest and Borer, Elizabeth T and Seabloom, Eric W and Harpole, W Stanley and Lind, Eric M and MacDougall, Andrew S and Stevens, Carly J and Adler, Peter B and Alberti, Juan 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 La Pierre, Kimberly J and McCulley, Rebecca L and Morgan, John W 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} }