As climate change is predicted to shift landscape composition and connectivity, individuals living at the upper range limits for their species may experience more opportunities for colonization into higher latitudes or elevations. The persistence of these new populations may depend on several factors, including habitat quality, climate conditions, and connectivity to the source population. Untangling which of these multiple factors is most influential in predicting species survival at the edge of its range during expansion would lead to higher probabilities that species do not go extinct as the global climate shifts. In their new paper, Lawson et al. identify local and landscape determinants of population establishment, density and survival using a thermally constrained butterfly found in the UK, and provide specific management recommendations focused on species range expansion.
Using a long term data set that includes presence records for the silver-spotted skipper butterfly (Hesperia comma), the authors were able to compare patches where the species was found from 2000-2009. Their results confirm previous findings that maintaining landscape level connectivity is important for managing species range shifts. Their new findings suggest that local management practices that focus on improving survival rates at new patches are key to ensuring species survival at expanding range margins. Connectivity (both direct and indirect) to multiple patches is crucial in determining colonization probability, although ensuring connectivity at a local level can be challenging unless there is landscape level cooperation among management. They recommend complementary strategies for facilitating species’ range shifts: encouraging colonization through habitat connectivity, and increasing habitat patch quality or size to support species survival. With these focused management recommendations, they are able to provide new useful methods for dealing with future potential range shifts.