Response diversity is a major driver of temporal stability in complex food webs

Abstract

Global change constitutes a major threat to biodiversity and ecosystem functioning which can materialise in the temporal stability of ecological communities. However, the majority of research on stability has focused on single trophic level communities and has not yet integrated classic theory about species richness and food web structure with more recent theory centred on response diversity and stochasticity. Using a stochastic, bioenergenetic food web model, we integrate these multiple bodies of theory to reveal that response diversity is a major driver of community stability. Moreover, our integrated theory reveals that positive stability-richness relationships emerge only in the presence of response diversity. In contrast to previous work, food web structure is only a secondary driver of community stability, but interacts with response diversity to determine the sign of the stability-richness relationship. Our study reveals identifiable pathways by which food web structure and response diversity drive community stability, and raises concerns about how the loss of response diversity (biotic homogenisation) may lead to a breakdown of community stability.