Linking Biotic Interactions to Species Stability

Ecological communities are typically composed of many species, each interacting with many others. This complexity makes it difficult to predict their responses to disturbances. Here a mathematical analysis of ecological models reveals a surprisingly simple principle: species responses to diverse disturbances can be predicted by a single metric: self-regulation loss (SL). SL quantifies the extent to which self-regulation effectively weighs on species population dynamics and is a collective outcome of biotic interactions. In simulated communities, SL accurately predicts species responses to pulse and press disturbances. On data from protist community experiments, SL successfully forecasts species responses to temperature changes. We therefore propose that, despite the complexity of ecological communities, species dynamics may still be governed by a simple organizing principle.