Arthropod herbivores cause substantial economic costs that drive an increasing need to develop environmentally sustainable approaches to herbivore control. Increasing plant diversity is expected to limit herbivory by altering plant-herbivore and predator-herbivore interactions, but the simultaneous influence of these interactions on herbivore impacts remains unexplored. We compiled 487 arthropod food webs in two long-running grassland biodiversity experiments in Europe and North America to investigate whether and how increasing plant diversity can reduce the impacts of herbivores on plants. We show that plants lose just under half as much energy to arthropod herbivores when in high-diversity mixtures versus monocultures and reveal that plant diversity decreases effects of herbivores on plants by simultaneously benefiting predators and reducing average herbivore food quality. These findings demonstrate that conserving plant diversity is crucial for maintaining interactions in food webs that provide natural control of herbivore pests.
Bibliographical noteFunding Information:
This study was funded by the German Research Foundation (FOR 1451). The Cedar Creek Biodiversity Experiment was supported by grants from the U.S. National Science Foundation Long-Term Ecological Research Program (LTER), including DEB-0620652 and DEB-1234162, and by the University of Minnesota. A.D.B., U.B., B.G., D.P.G., J.H., C.R., and N.E. also acknowledge support from the German Research Foundation (FZT 118).
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