Isolation of lizard populations measured with molecular genetic data – Podarcis guadarramae in the Ria de Arosa archipelago

Under a documented paleogeographic history of the Ria de Arosa archipelago, northwestern Spain, predictions can be made on the duration and strength of isolation of Podarcis guadarramae lizard populations that were ‘captured’ on the islands when sea-levels rose. We predict that genetic diversity: i) is lower on islands than on the mainland, ii) increases with island size, and iii) decreases with increasing distance from the mainland. We also predict that the population genetic structure across islands and the mainland conforms to a pattern of isolation by distance (iv). To test these hypotheses, we analysed a panel of nine highly polymorphic microsatellite loci. The first (i) hypothesis was corroborated. We discuss our findings in the light of the effects of habitat fragmentation and lizard conservation.