Plant species’ origin predicts dominance and response to nutrient enrichment and herbivores in global grasslands

Seabloom, Eric W. and Borer, Elizabeth T. and Buckley, Yvonne M. and Cleland, Elsa E. and Davies, Kendi F. and Firn, Jennifer and Harpole, W. Stanley and Hautier, Yann and Lind, Eric M. and Macdougall, Andrew S. and Orrock, John L. and Prober, Suzanne M. and Adler, Peter B. and Anderson, T. Michael and Bakker, Jonathan D. and Biederman, Lori A. and Blumenthal, Dana M. and Brown, Cynthia S. and Brudvig, Lars A. and Cadotte, Marc and Chu, Chengjin and Cottingham, Kathryn L. and Crawley, Michael J. and Damschen, Ellen I. and Dantonio, Carla M. and Decrappeo, Nicole M. and Du, Guozhen and Fay, Philip A. and Frater, Paul and Gruner, Daniel S. and Hagenah, Nicole and Hector, Andy and Hillebrand, Helmut and Hofmockel, Kirsten S. and Humphries, Hope C. and Jin, Virginia L. and Kay, Adam and Kirkman, Kevin P. and Klein, Julia A. and Knops, Johannes M. H. and La Pierre, Kimberly J. and Ladwig, Laura and Lambrinos, John G. and Li, Qi and Li, Wei and Marushia, Robin and McCulley, Rebecca L. and Melbourne, Brett A. and Mitchell, Charles E. and Moore, Joslin L. and Morgan, John and Mortensen, Brent and O'Halloran, Lydia R. and Pyke, David A. and Risch, Anita C. and Sankaran, Mahesh and Schuetz, Martin and Simonsen, Anna and Smith, Melinda D. and Stevens, Carly J. and Sullivan, Lauren and Wolkovich, Elizabeth and Wragg, Peter D. and Wright, Justin and Yang, Louie (2015) Plant species’ origin predicts dominance and response to nutrient enrichment and herbivores in global grasslands. Nature Communications, 6. ISSN 2041-1723

Abstract

Exotic species dominate many communities; however the functional significance of species’ biogeographic origin remains highly contentious. This debate is fuelled in part by the lack of globally replicated, systematic data assessing the relationship between species provenance, function and response to perturbations. We examined the abundance of native and exotic plant species at 64 grasslands in 13 countries, and at a subset of the sites we experimentally tested native and exotic species responses to two fundamental drivers of invasion, mineral nutrient supplies and vertebrate herbivory. Exotic species are six times more likely to dominate communities than native species. Furthermore, while experimental nutrient addition increases the cover and richness of exotic species, nutrients decrease native diversity and cover. Native and exotic species also differ in their response to vertebrate consumer exclusion. These results suggest that species origin has functional significance, and that eutrophication will lead to increased exotic dominance in grasslands.