Herbivores and nutrients control grassland plant diversity via light limitation

BORER, E; ET AL.; O. IRIBARNE,; ET AL.

NATURE

NATURE PUBLISHING GROUP

Lugar: Londres; Año: 2014 vol. 508 p. 517 - 520

0028-0836

Human alterations tonutrient cycles1,2 andherbivore communities3?7 are affecting global biodiversity dramatically2. 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 systems8,9. Here we use experimental data spanning a globally relevant range of conditions to test the hypothesis that herbaceous plant species losses caused by eutrophicationmay be offset by increased light availability due to herbivory. This experiment, replicated in 40 grasslands on 6 continents, demonstrates that nutrientsand 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 fromanthropogenic eutrophication can beameliorated in grasslands where herbivory increases ground-level light.