Molecular phylogeography of the common dormouse, Muscardinus avellanarius, in Europe

The common dormouse, Muscardinus avellanarius is naturally rare in Europe. Recently, natural
scarcity has been exacerbated by anthropogenic environmental damages. This specie is now regarded
as rare or endangered, attracting conservation related research and active habitat management to assist
its survival. Furthermore, obligatory thermophilous species are probably more affected by cold phases
than cold-tolerant organisms. The evolutionary history of the common dormouse would therefore
show significant differences compared to other species.
To better understand the genetic variation and structure of this species, we developed a
phylogeographic study based on sequences of 700 base pairs of the mitochondrial DNA cytochrome b
gene from 102 specimens collected throughout its palearctic distribution. The obtained dataset was
analysed using different phylogenetic reconstruction as well as other methods adapted to
phylogeography.
The analysis of the mtDNA reveals a number of surprises. The results show two major genetic
lineages: the first corresponding to the Western and Italian populations; the second comprising the
Balkan and the Northern populations. Furthermore, the analyses tend to propose a scenario of multiple
refugia in the Italian peninsula.
This pattern of ‘refugia within-refugia’ has important implications in interpreting the distribution
patterns of genetic diversity within the southern peninsulas. The Calabria region and Sicily could be
“hot spots” of intraspecific biodiversity of Muscardinus avellanarius. These regions would thus
deserve attention when deciding Evolutionary Significant Units (“ESU) for conservation of this
species.