The past three decades have seen major progress in understanding the role of biodiversity in ecosystem functioning and stability. A significant number of experiments showed that biodiversity promoted the functioning and stability of ecosystems, and new theory and hypotheses have been developed to explain the positive effects of biodiversity observed in experiments. Although ecosystem functioning and stability were both shown to generally increase with biodiversity, experimental data exhibits large variation within a given level of biodiversity. It remains largely unknown whether communities with a higher functioning tend to have a higher or lower stability. Both functioning and stability are ecosystem-wide properties emerging from species interactions and population dynamics, so it requires mechanistic approaches to clarify the biotic mechanisms underlying the functioning-stability relationship.
Results/Conclusions
In this study, we used community models to examine how complementarity and selection, the two biotic mechanisms of ecosystem functioning, affect the stability of ecosystems in the face of perturbations. Our results showed that while complementarity promotes stability, selection impairs it. Consequently, ecosystem functioning and stability exhibit either a synergy, along the gradient of niche complementarity, or a trade-off, along the gradient of selection. The negative effect of selection on stability is mediated through weakening species insurance effects or selecting risk-prone species that have higher biomass but lower tolerance to perturbations. Our findings provide novel insights for understanding the relationship between the functioning and stability of ecosystems, with important implications for ecosystem management.