Quantifying dynamical response diversity and its influences on ecosystem stability

Response diversity—the variation in species’ responses to environmental changes and to other species—has been recognized as a critical feature in maintaining the resilience and stability of ecosystem-level properties, such as total biomass. However, quantifying response diversity remains challenging. A key issue is the context-dependence nature of species responses: a species’ reaction to a specific environmental factor can vary depending on environmental conditions or interactions with other species. Consequently, these responses are dynamic rather than static. We propose a novel framework to quantify response diversity, incorporating time-varying species' responses to biotic and abiotic factors and accommodating high-dimensional, nonlinear interactions in complex systems without assuming equilibrium. Using a 40-year monthly dataset from Lake Geneva, we show that response diversity of the phytoplankton and zooplankton community stabilizes their respective biomass within but not across trophic levels. Importantly, the stabilizing effect of response diversity varies over time, being context-dependent on time-varying environmental conditions. Our method opens new avenues for uncovering the mechanisms linking biodiversity and ecosystem dynamics.