Response diversity is key to buffer ecosystem productivity against multiple environmental change drivers

Evidence shows that biodiversity promotes primary productivity. However, it is unclear whether such biodiversity-productivity relationships persist under increasing numbers of environmental changes in the current Anthropocene. Here, we use theoretical and experimental approaches to demonstrate that variation in species responses to changing environments determines the ability of ecological communities to maintain productivity under multiple types of environmental change. Our theory shows that this response diversity determines whether biodiversity-productivity relationships are enhanced or impaired by environmental changes. Communities with high response diversity are expected not only to be productive in a particular environment but to maintain that productivity under multiple conditions. Nevertheless, our theory also predicts that such buffering effects fade with increasing negative environmental impacts on communities. Consistent with this prediction, our biodiversity experiment reveals impaired biodiversity-productivity relationships under multiple environmental change drivers with a negative mean impact. Our results suggest that, in the face of growing multiplicity of environmental changes, policies should encourage conservation of local biota, enabling communities to respond to unprecedented environments that may arise.