Change in dominance determines herbivore effects on plant biodiversity

Sally E. Koerner*, Melinda D. Smith, Deron E. Burkepile, Niall P. Hanan, Meghan L. Avolio, Scott L. Collins, Alan K. Knapp, Nathan P. Lemoine, Elisabeth J. Forrestel, Stephanie Eby, Dave I. Thompson, Gerardo A. Aguado-Santacruz, John P. Anderson, T. Michael Anderson, Ayana Angassa, Sumanta Bagchi, Elisabeth S. Bakker, Gary Bastin, Lauren E. Baur, Karen H. BeardErik A. Beever, Patrick J. Bohlen, Elizabeth H. Boughton, Don Canestro, Ariela Cesa, Enrique Chaneton, Jimin Cheng, Carla M. D’Antonio, Claire Deleglise, Fadiala Dembélé, Josh Dorrough, David J. Eldridge, Barbara Fernandez-Going, Silvia Fernández-Lugo, Lauchlan H. Fraser, Bill Freedman, Gonzalo García-Salgado, Jacob R. Goheen, Liang Guo, Sean Husheer, Moussa Karembé, Johannes M.H. Knops, Tineke Kraaij, Andrew Kulmatiski, Minna Maarit Kytöviita, Felipe Lezama, Gregory Loucougaray, Alejandro Loydi, Dan G. Milchunas, Suzanne J. Milton, John W. Morgan, Claire Moxham, Kyle C. Nehring, Han Olff, Todd M. Palmer, Salvador Rebollo, Corinna Riginos, Anita C. Risch, Marta Rueda, Mahesh Sankaran, Takehiro Sasaki, Kathryn A. Schoenecker, Nick L. Schultz, Martin Schütz, Angelika Schwabe, Frances Siebert, Christian Smit, Karen A. Stahlheber, Christian Storm, Dustin J. Strong, Jishuai Su, Yadugiri V. Tiruvaimozhi, Claudia Tyler, James Val, Martijn L. Vandegehuchte, Kari E. Veblen, Lance T. Vermeire, David Ward, Jianshuang Wu, Truman P. Young, Qiang Yu, Tamara Jane Zelikova

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

157 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)1925-1932
Number of pages8
JournalNature Ecology and Evolution
Issue number12
Publication statusPublished - 1 Dec 2018
Externally publishedYes

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