Edge effects influence competition dynamics: A case study of four sympatric arboreal marsupials

Edge effects are widely researched phenomena in ecology. However, little is known about their influence on the competition dynamics of sympatric species. We present a new conceptual model to explain how edge effects and competition dynamics interact to influence community composition and illustrate it with a case study of four sympatric arboreal marsupial species in Australia. For the first time, we demonstrate that edge effects on interspecific competition influence community composition in naturally co-occurring species. We found that Petauroides volans, a eucalypt folivore specialist, was significantly more edge-avoidant than the other three more generalist folivore species, Trichosurus vulpecula, Trichosurus cunninghami, and Pseudocheirus peregrinus. As the amount of edge increased, the abundance and probability of occurrence of P. volans decreased. We found the opposite pattern for the other species. We propose that edge effects differentially affect resource availability for these species and increase competitive pressure for tree hollows, which are a limited common resource.

► We present a case study showing edge effect (EE) impacts on competition and community composition.
► We illustrate this interaction with a new conceptual model of EE on competition dynamics.
► Differing EE responses of sympatric species can increase competitive pressure for common resources.