Jose Luis Horreo, Maria Luisa Pelaez, Merel Cathelijne Breedveld, Teresa Suarez, Maria Urieta, Patrick S. Fitze

• Gene flow is an important factor determining the evolution of a species, since it directly affects population structure and species’ adaptation. Here, we investigated population structure, population history, and migration among populations covering the entire distribution of the geographically isolated South-West European common lizard (Zootoca vivipara louislantzi) using 34 newly developed polymorphic microsatellite markers. The analyses unravelled the presence of isolation by distance, inbreeding, recent bottlenecks, genetic differentiation, and low levels of migration among most populations, suggesting that Z. vivipara louislantzi is threatened. The results point to discontinuous populations and are in line with physical barriers hindering longitudinal migration south to the central Pyrenean cordillera and latitudinal migration in the central Pyrenees. In contrast, evidence for longitudinal migration exists from the lowlands north to the central Pyrenean cordillera and the Cantabrian Mountains. The locations of the populationsGene flow is an important factor determining the evolution of a species, since it directly affects population structure and species’ adaptation. Here, we investigated population structure, population history, and migration among populations covering the entire distribution of the geographically isolated South-West European common lizard (Zootoca vivipara louislantzi) using 34 newly developed polymorphic microsatellite markers. The analyses unravelled the presence of isolation by distance, inbreeding, recent bottlenecks, genetic differentiation, and low levels of migration among most populations, suggesting that Z. vivipara louislantzi is threatened. The results point to discontinuous populations and are in line with physical barriers hindering longitudinal migration south to the central Pyrenean cordillera and latitudinal migration in the central Pyrenees. In contrast, evidence for longitudinal migration exists from the lowlands north to the central Pyrenean cordillera and the Cantabrian Mountains. The locations of the populations south to the central Pyrenean cordillera were identified as the first to be affected by global warming; thus, management actions aimed at avoiding population declines should start in this area.…