Dispersal mediates metapopulation response to local and regional stressors

Abstract

Many populations face multiple Anthropogenic threats simultaneously, and as a result, we have observed loss of biodiversity worldwide. Moreover, population stressors act at different spatial scales, and the understanding of variation in outcomes for species will depend on their dispersal ability. In this study, we developed a spatially explicit metapopulation simulation to investigate how stressors that act at different spatial scales interact with landscape composition and dispersal behavior to drive patterns of metapopulation extirpations. We are particularly interested in gaining insight into the decline of not only range-limited species, but also widespread butterflies that have been reported in recent years, contrary to conventional wisdom about traits that make species more at risk of population decline. We found that stressors acting at different spatial scales interact with dispersal, especially in highly developed landscapes. On average, being less dispersive produces worse outcomes because more dispersive species benefit from semi-natural habitats, which can strengthen connections between source populations. At the same time, it is the degradation of these types of land in particular that may disproportionately impact dispersive species. These findings enhance our understanding of insect biodiversity loss and demonstrate that the conservation of widespread insects will likely require consideration of larger-scale landscape connectivity.