Herbivores and nutrients control grassland plant diversity via light limitation

Human alterations to nutrient cycles and herbivore communities are affecting global biodiversity dramatically. Ecological theory predicts these changes should be strongly counteractive: nutrient addition drives plant species loss through intensified competition for light, whereas herbivores prevent competitive exclusion by increasing ground-level light, particularly in productive systems. Here we use experimental data spanning a globally relevant range of conditions to test the hypothesis that herbaceous plant species losses caused by eutrophication may be offset by increased light availability due to herbivory. This experiment, replicated in 40 grasslands on 6 continents, demonstrates that nutrients and herbivores can serve as counteracting forces to control local plant diversity through light limitation, independent of site productivity, soil nitrogen, herbivore type and climate. Nutrient addition consistently reduced local diversity through light limitation, and herbivory rescued diversity at sites where it alleviated light limitation. Thus, species loss from anthropogenic eutrophication can be ameliorated in grasslands where herbivory increases ground-level light. © 2014 Macmillan Publishers Limited.Fil: Borer, Elizabeth. University of Minnesota; Estados UnidosFil: Seabloom, Eric. University of Minnesota; Estados UnidosFil: Gruner, Daniel. University of Maryland; Estados UnidosFil: Harpole, Stanley. Iowa State University; Estados UnidosFil: Hillebrand, Helmut. Carl-von- Ossietzky University; AlemaniaFil: Lind, Eric M.. University of Minnesota; Estados UnidosFil: Adler, Peter B.. Utah State University; Estados UnidosFil: Alberti, Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Anderson, Michael. Wake Forest University; Estados UnidosFil: Bakker, Jonathan D.. University of Washington; Estados UnidosFil: Biederman, Lori. Iowa State University; Estados UnidosFil: Blumenthal, Dana. United States Department of Agriculture. Agricultural Research Service; Estados UnidosFil: Brown, Cynthia S.. State University of Colorado - Fort Collins; Estados UnidosFil: Brudvig, Lars A.. University of Minnesota; Estados UnidosFil: Buckley, Yvonne M.. The University Of Queensland; AustraliaFil: Cadotte, Marc. University of Toronto Scarborough; CanadáFil: Chu, Chengjin. Lanzhou University; ChinaFil: Cleland, Elsa. University of California; Estados UnidosFil: Crawley, Michael. Imperial College at Silwood Park; Reino UnidoFil: Daleo, Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Damschen, Ellen. University of Wisconsin; Estados UnidosFil: Davies, Kendi. State University of Colorado - Fort Collins; Estados UnidosFil: DeCrappeo, Nicole. Forest and Rangeland Ecosystem Science Center; Estados UnidosFil: Du, Guozhen. Lanzhou University; Estados UnidosFil: Firn, Jennifer. Queensland University of Technology; AustraliaFil: Hautier, Yann. University of Minnesota; Estados UnidosFil: Heckman, Robert. University of North Carolina at Chapel Hill; Estados UnidosFil: Hector, Andy. University of Oxford; Reino UnidoFil: Hillerislambers, Janneke. University of Washington; Estados UnidosFil: Iribarne, Oscar Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Klein, Julia. State University of Colorado - Fort Collins; Estados UnidosFil: Knops, Johannes M. H.. University of Nebraska; Estados UnidosFil: La Pierre, Kimberly. University of California; Estados UnidosFil: Leakey, Andrew D. B.. University of Illinois at Urbana-Champaign; Estados UnidosFil: Li, Wei. Iowa State University; Estados UnidosFil: MacDougall, Andrew S.. University of Guelph; CanadáFil: McCulley, Rebecca. University Of Kentucky; Estados UnidosFil: Melbourne, Brett. State University of Colorado - Fort Collins; Estados UnidosFil: Mitchell, Charles. University of North Carolina at Chapel Hill; Estados UnidosFil: Moore, Joslin. University of Melbourne; AustraliaFil: Mortensen, Brent. Iowa State University; Estados UnidosFil: O'Halloran, Lydia. Oregon State University; Estados UnidosFil: Orrock, John. University of Wisconsin; Estados UnidosFil: Pascual, Jesus Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Prober, Suzanne. CSIRO Ecosystem Sciences; AustraliaFil: Pyke, David. Forest and Rangeland Ecosystem Science Center; CanadáFil: Risch, Anita. Swiss Federal Institute For Forest, Snow And Landscape Research; SuizaFil: Schuetz, Martin. Swiss Federal Institute For Forest, Snow And Landscape Research; SuizaFil: Smith, Melinda D.. State University of Colorado - Fort Collins; Estados UnidosFil: Stevens, Carly. Lancaster University; Reino UnidoFil: Sullivan, Lauren. Iowa State University; Estados UnidosFil: Williams, Ryan. Iowa State University; Estados UnidosFil: Wragg, Peter. University of Minnesota; Estados UnidosFil: Yang, Louie. University of California; Estados Unido