Response balance - a neglected mechanism stabilising ecosystem

Understanding how ecological communities remain stable under environmental change, or fail to do so, is key to predicting the sustainable provision of ecosystem services and the resilience of nature-positive futures. One theory suggests that response diversity, the variation in how species respond to environmental fluctuations, can buffer communities against the effects of environmental change, reduce fluctuations, and enhance resilience. Nevertheless, the effects of response diversity are relatively poorly understood, may vary across disturbance regimes, and may weaken when species interact strongly with each other. Furthermore, how to measure response diversity from species traits, and how to scale such measurements from local community scales to broader spatial and temporal scales, remains unclear. Using a combination of mathematical model simulations, meta-analyses of field experiments, and laboratory studies, we have advanced understanding of how species’ responses combine to stabilize ecosystems. In particular, we found that community stability is driven largely by the distribution of species’ fundamental responses, with relatively weak effects of interactions among species, irrespective of the type of environmental disturbance. Moreover, novel metrics of response diversity and response balance show considerable potential as trait-based predictors of ecosystem stability. This is partly because they integrate the effects of both population stability and population asynchrony. Results also suggest that more traditional diversity metrics, such as dissimilarity, may be less effective predictors of ecosystem stability. Among other outstanding questions is the challenge of scaling up the measurement of trait-based response diversity and balance to larger spatial scales. At such scales, it remains unclear how to gather the required trait data or whether assumptions that could reduce data requirements can be justified. Ultimately, improving our ability to quantify and scale response diversity will be essential for predicting and managing ecosystem resilience in a rapidly changing world. This work lays the foundation for developing practical tools that link biodiversity traits to ecosystem stability across scales.