On the robustness of species coexistence to environmental perturbations

Abstract

AbstractHere we examine how biotic interactions determine the robustness of species coexistence in the face of environmental perturbations. For Lotka-Volterra community models, given a set of biotic interactions, recent approaches have characterized, and applied, the probability of finding at set of species intrinsic features (e.g. intrinsic growth rates) that will allow coexistence. Here we ask instead: if species do coexist, given their interactions, how fragile this coexistence should be to variations in species demographic parameters ? This change of framing allows us to derive the essential features of interactions that determine the robustness of coexistence, while not reducing it to a single number. As we illustrate on data from experimental plant community experiments, our results generate new ways to study species’ contextual role in maintaining coexistence, and allows us to quantify the extent to which species intrinsic features and biotic interactions favourably combine (making coexistence more robust than expected), or oppose (making coexistence less robust than expected). Because it has both as central tenets, our work helps synthesize coexistence and ecological stability theories.