Modeling the effects of trait-mediated dispersal on coexistence of two species: Competition and non-consumptive...

Fragmentation and loss of habitat owing to increased human activity are major drivers of species extinctions and declining global biodiversity. In ecological communities, trait-mediated indirect effects are frequently observed and can influence population dynamics as strongly, possibly even more strongly, than direct effects. However, few studies have focused on trait-mediated behavior such as trait-mediated dispersal, in which the dispersal patterns are altered by the presence of an interacting species. Moreover, little is known about how trait-mediated dispersal interacts with habitat fragmentation and loss to affect the coexistence of interacting species. Here, we explore the consequences of both trait-mediated dispersal and fragmentation/loss on coexistence in a system consisting of two competing species or a predator and its prey. By assuming that the density-mediated effects are negligible, we isolate the role of trait-mediated effects. Our results show that the combined influence of fragmentation and trait-mediated dispersal can substantially reshape the population dynamics and species coexistence outcomes.