Species interactions limit the predictability of community responses to environmental change

Predicting how ecological communities respond to environmental change is challenging, but highly relevant in this global change era. Ecologists commonly use current spatial relationships between species and environmental conditions to make predictions about the future. This assumes that species will track conditions by shifting their distributions. However, theory and experimental evidence suggest that species interactions prevent communities from predictably tracking temporal changes in environmental conditions, based on current spatial relationships between species and environmental gradients. We tested this hypothesis by assessing the dynamics of protist species in replicated two-patch microcosm landscapes that experienced different regimes of spatial and temporal environmental heterogeneity (light vs. dark). Populations were kept in monoculture or polyculture to assess the effect of species interactions. In monoculture, abundances were predictable based on current environmental cond...