Range expansion and retraction along a moving contact zone has no effect on the genetic diversity of two passerine birds
Disentangling the factors shaping species distributions remains a central goal in biogeography, ecology and evolutionary biology. The extrinsic pressures that may facilitate range shifts, such as climatic factors or biotic interactions are well known. However, in contrast, the possible intrinsic factors are manifold and hard to generalize across taxa. Recently, several theoretical studies have inv