The interplay between biogeography and environment: a multi-locus, multi-species case study in the Eastern Italian Alps.

The identification of the ecological and environmental factors shaping patterns of natural genetic variation is a fundamental goal of population and conservation genetics. Until recently many studies focused on factors affecting single species, but an emerging interest is whether some influential biotic and abiotic factors are common drivers of genetic diversity across species, or if species or species groups are each affected by different forces; a multi-species analysis is necessary for this goal. Here we analysed the molecular variation in 500 specimens from five mammal species at mtDNA and microsatellite loci (roe deer, red deer, chamois, mountain hare and European brown hare) from the eastern Italian Alps. We use phylogeographic and landscape-level analyses to test the relative influence of large-scale geographic history and contemporary environmental characteristics of the landscape. We found: (i) all study species except brown hare are strongly differentiated into two main groups, located west and east of a major river valley; (ii) no correlation between genetic, geographic and ecological distance; (iii) weak correlations between levels of within population diversity at both mtDNA and microsatellite loci, and several landscape features such as alpine grassland, water courses and anthropized areas. We conclude that heterogeneous landscape has some influence on within population diversity, but biogeographical history has likely had the stronger influence on current genetic patterns, despite an apparently large dispersal potential of certain species. However, management actions such as stocking may alter these large scale patterns.