Geographically peripheral populations are likely to experience suboptimal conditions, and several population characteristics may be influenced. The aim of the present study was to assess characteristics of the populations of hazel, forest and fat dormice on the northern periphery of their ranges in continental Europe in comparison to populations situated in the rest of their ranges. The dormouse populations analysed were found to be distinct from other populations in many aspects of their ecology. On this northern periphery of the ranges, the dormouse activity season is shorter and ends earlier. The population density is also lower, but inter-annual abundance dynamics are comparatively stable. Except the shorter breeding season however, there is no clear general pattern regarding other aspects of reproduction. The composition of the vegetable food used by dormice is rather specific. Contrary to expectations, the proportion of food of animal origin is not increased in the dormouse diets. The main habitat requirements of dormice are similar to those in other parts of their ranges, though the composition of woody plant species in the dormouse habitats is different. Dormice living on the northern periphery of their ranges show a high degree of adaptability to local conditions, but factors limiting their distribution are not clear yet.
On the basis of previous studies of the common dormouse Muscardinus avellanarius concentrated on deciduous woodlands in the southern counties of Great Britain, it was stated that optimal habitat for M. avellanarius should contain a high diversity of suitable shrub and tree species to provide continuous food supply through activity season and appropriate physical structure. However, both the present review of M. avellanarius habitats within its distributional range and recent dormouse studies in other parts of Great Britain indicate that M. avellanarius actually inhabits a much wider variety of habitats, and do not require specialised habitats as previously supposed. M. avellanarius habitats in Lithuania differ considerably from the optimal habitats described for this species, about 40 % of localities being situated in coniferous- dominated forests. Habitat quality may result in a very low average population density of only about one adult per hectare. However, despite of absence of optimal habitats and low population density, M. avellanarius is widespread in Lithuania, and no decline is observed in their abundance and distribution. Forest management (increasing forest cover, planting of native tree species, not too large fragmentation of forest tracts) has been favourable for M. avellanarius in Lithuania.