Near-shore island lizard fauna shaped by a combination of human-mediated and natural dispersal

Aim: Island biotas provide opportunities to study colonization and adaptation to novel environments. Islands, especially near-shore islands, may have a long record of human habitation such that some lineages result from human-assisted introductions. Here, we combine phylogenetic analyses with fossil data and historical specimen records to reconstruct colonization histories, characterize among-island divergence, and assess the role of humans in shaping the evolutionary history of lizards inhabiting a near-shore island archipelago. Location: Channel Islands and adjacent mainland of California, USA. Taxa: Western fence lizard ( Sceloporus occidentalis), southern alligator lizard (Elgaria multicarinata), common side-blotched lizard (Uta stansburiana). Methods: We sequenced mitochondrial DNA (ND1, cyt-b) from each of three lizard species, covering their entire island distributions plus the adjacent mainland. For each, we estimated diversity within and among each island, obtained maximum like...