Biogeographic and phylogenetic expectations for a ‘vicariance by erosion’ scenario as hypothesized for the southern Cumberland Plateau. A–C Karst (gray) erodes and fragments over time, leading to the isolation and divergence of cave populations (colored circles) in the remaining patches of karst D A phylogeny consistent with the vicariance by erosion process, with taxa that diverge early distributed at the periphery of the eroding region.