Ecological barriers mediate spatiotemporal shifts of bird communities

Abstract Species’ range shifts and local extinctions caused by global change lead to community composition changes. At large spatial scales, ecological barriers, such as biome boundaries, coastlines, elevation, and temperature gradients, can influence a community's ability to shift. Yet, ecological barriers are rarely considered in global change studies, potentially hindering predictions of biodiversity shifts. We used data from two consecutive European breeding bird atlases to calculate the geographic distance and direction between communities in the 1980's and their nearest compositional equivalent in the 2010’s and modelled their response to barriers. The ecological barriers affected both the distance and direction of bird community composition shifts, with coasts and elevation having the strongest influence. Combining ecological barriers and community shift projections can identify ecological corridors that facilitate shifts of species and communities under global change.