A complex scenario of glacial survival in Mediterranean and continental refugia of a temperate continental vole species (Microtus arvalis) in Europe.
The role of glacial refugia in shaping contemporary species distribution is a long-standing question in phylogeography and evolutionary ecology. Recent studies are questioning previous paradigms on glacial refugia and postglacial recolonization pathways in Europe, and more flexible phylogeographic scenarios have been proposed. We used the widespread common vole Microtus arvalis as a model to investigate about the origin, locations of glacial refugia and dispersal pathways, in the group of “Continental” species in Europe. We used a Bayesian spatio-temporal diffusion analysis (relaxed random walk model) of cytochrome b sequences across the species range, including newly collected individuals from 10 Iberian localities and published sequences from 68 localities across 22 European countries. Our data suggest that the species originated in Central Europe, and we revealed the location of multiple refugia (in both southern peninsulas and continental regions) for this continental model species. Our results confirm the monophyly of Iberian voles and the pre-LGM divergence between Iberian and European voles. We found evidence of restricted post-glacial dispersal from refugia in Mediterranean peninsulas. We inferred a complex evolutionary and demographic history of M. arvalis in Europe over the last 50,000 years that does not adequately fit previous glacial refugia scenarios. The phylogeography of M. arvalis provides a paradigm of ice-age survival of a temperate continental species in western and eastern Mediterranean peninsulas (sources of endemism) and multiple continental regions (sources of postglacial spread). Our findings also provide support for a major role of large European river systems in shaping geographical boundaries of M. arvalis in Europe.