Anthropogenic dispersal explains the phylogeography of insular edible dormouse Glis glis in the Mediterranean basin

The history of human colonisation in the Mediterranean has long been recognised as a crucial factor influencing biodiversity patterns in southern Europe. Nonetheless, our understanding of how anthropogenic and natural dispersal events interacted in shaping wildlife distributions, particularly in small mammals, remains limited. The edible dormouse Glis glis, a widespread European species, whose distribution includes several islands in the Mediterranean, present an opportunity to investigate these interactions. In this work, we used the edible dormouse to test hypotheses regarding the interplay between natural and anthropogenic dispersal in shaping species’ distributions in Mediterranean archipelagos. We compared genetic sequences from samples collected on Mediterranean islands (Elba Island, Corsica, Sardinia, Sicily and Salina Island) and the mainland. Twenty-one samples were analysed by amplifying and sequencing a fragment of the cytochrome oxidase subunit I gene. Results indicated that samples from Sardinia and Elba Island belong to the same clade of mainland Italy, specifically to the subspecies G. g. italicus. This finding does not support the existence of an endemic Sardinian subspecies and suggests recent introduction events. In contrast, Salina Island only included individuals belonging to the Sicilian subspecies, whereas Sicily hosts a mixed population of G. g. italicus and G. g. insularis. The Corsican population likely originated from a different stock than Sardinia, possibly originating from Northern Italy or southern France. Overall, our findings underscore the significant role of anthropogenic dispersal in shaping the current distribution of the edible dormouse on islands.