Population-genetic structure of the hazel dormouse Muscardinus avellanarius in the Meuse-Rhine Euregion

The survival of many species has been impacted dramatically by human activities over the last few centuries. More specifically, forest fragmentation, due to human settlement and development of agriculture, has highly affected arboreal species. Understanding patterns of genetic structure of endangered species occupying fragmented forest habitats is a requirement for appropriate conservation management, especially for species with low dispersal abilities like the hazel dormouse ( Muscardinus avellanarius ). The hazel dormouse is an arboreal rodent that is strictly protected in Europe. The aim of this study conducted from 2004 to 2011 was to investigate population fragmentation of the hazel dormouse in part of the Meuse-Rhine Euregion using microsatellite markers. The results revealed a significant genetic differentiation and low gene flow between subpopulations. Fragmentation of the hazel dormouse population in this region seems to have occurred during the 20th century, suggesting that active management to improve habitat quality, amount of habitat and connectivity is essential to impede future genetic erosion. Furthermore, our results show that railway verges, like other linear habitat elements, cannot only be permanently inhabited, but also act as a valuable corridor, connecting subpopulations and allowing the colonisation of new sites. Finally, in response to our study, both Flemish and Dutch hazel dormouse species protection plans included the objective of providing a functional ecological corridor between several of the subpopulations, which has already been partially implemented.