No positive effects of biodiversity on ecological resilience of lake ecosystems

Abstract

<p>Ecological resilience is critical for ecosystems to persist in the face of perturbations without shifting to a different state. Global biodiversity loss in multiple ecosystems is considered to be associated with decreasing ecological resilience and increasing the risk of ecosystem collapse. However, how temporal changes in biodiversity affect ecological resilience in natural ecosystems remains poorly elucidated. By analyzing subfossil records of diatoms, chironomids, and cladocerans from 53 lake sediment cores across the globe, we found that species richness showed an increasing trend with time, while beta diversity and ecological resilience presented a decreasing temporal trend when ecosystems are approaching the abrupt shift. Asynchronous fluctuations among species and temporal stability at species level are suggested to be the mechanisms that contribute to the maintenance of temporal community stability. We found species richness and beta diversity have positive effects on species asynchrony but negative effects on species stability. However, we found that species asynchrony and species stability had negative relationships with ecological resilience, with species richness and beta diversity overall having no positive effects on ecological resilience. We highlighted that biodiversity effects on ecological resilience are not only the role of species richness, but also the species assemblage and network complexity of species-species interactions. Our study indicates that increased species diversity and community heterogeneity may be not beneficial for the ecosystem to recover from disturbances at a lake ecosystem scale, which has great implications for the assessment of ecological resilience and predicting ecosystem collapse in future global environmental change scenarios.</p>