Asynchronous temporal fluctuations in species abundances can maintain species diversity and stabilize ecological functions. Species-specific responses to fluctuating climatic conditions, coupled with species interactions, often underlie asynchronous dynamics. However, there is little understanding of how changes in climatic means or variability alter asynchronous dynamics, or whether species interactions fundamentally change these relationships. We develop a multispecies storage effect model where species-specific responses to climate determine maximum growth rates and competitive impacts, and use this model to test i) how changing climate alters asynchrony, diversity and the stability of production when ecological communities are drawn from a common species pool, and ii) how within-community changes in species’ differential responses to climate alter the importance of asynchrony to stability as climate and competitive dynamics change.
Results/Conclusions
Increasing climatic variability caused unimodal responses of asynchrony and species diversity. When comparing communities with differing climate variability, stability increased with asynchrony, with this relationship strongest for weakly competing species and flattening or even declining for strongly competing species. Demographic stochasticity was central to many of these patterns, as it overwhelmed species-specific responses to climate when climatic variability was low, and elevated extinction rates when climatic variability was high. Changing mean climatic conditions shifted the height and position of the unimodal asynchrony – variability relationship and universally lowered stability. Within these overwhelming effects of shifting climate variability, the degree to which species responded differentially to climate conditions also influenced asynchrony and stability; greater differences in species responses increased asynchrony and tended to increase stability. Overall, our results show that abiotic drivers of asynchrony (climatic variability) and biotic drivers (differential species responses to climate) can have opposing effects on stability, generating complex relationships between asynchrony and stability.