Space use, daily activity and foraging behaviour of common dormouse (Muscardinus avellanarius) in a Mediterranean heterogeneous environment of Central Italy

Despite numerous field studies focused on the basic life history of the common dormouse, little is known about its movements and home range use. The knowledge of how dormice utilize their habitat is essential to outline appropriate conservation management of the species. Therefore, we conducted this study to gather first information on the spacing behaviour in a Mediterranean heterogeneous habitat, with a special attention to home range size, trek length and foraging behaviour. The study was carried out in the Natural Reserve of Castel di Guido, near Rome (41°54'N, 12°31'E), characterized by a mosaic of natural and artificial woods. Natural patches were represented by thermophilous mixed oak woodland dominated by Quercus ilex and Q. cerris, with a dense shrub layer. Artificial patches consisted of an assemblage of planted trees belonging to different species, either deciduous (i.e. Q. pubescens, Acer monspessulanum, Pyrus comunis) or evergreen (i.e. Pinus sp., Q. suber). Finally, edges were composed by several shrubs species as Prunus spinosa, Crataegus monogyna, Spartium junceum, Rubus fruticosus and Ulmus minor. In order to study the space use and daily activity, radiotracking was carried out in four sessions: two in winter (November-December 2003 and 2004) and two in spring (March-April 2004 and April-May 2005). Each session lasted three weeks. Common dormice were captured in nest boxes and were radiotagged using transmitters weighed 1.1 g. Only dormice with body weight of 15 g or more were tagged.Dormice resulted to be completely nocturnal: they left the nest after sunset and came back to it before dawn. Daily activity was affected by photoperiod and possibly by vegetation structure. In fact, when dormice had to move through areas with a scarce vegetation cover, they shortened their daily activity and avoided to move during twilight, probably to reduce the predation risk. Home range (HR) size resulted on average very small for both sexes (♀MCP = 0.36 ha; ♂ MCP = 0.32 ha) and in both seasons (spring MCP = 0.33 ha; winter MCP = 0.35 ha). However, individuals showed marked differences in space use, probably affected by the location and proximity of wood patches within the home range. In winter, dormice used the same area during the three weeks, while in spring the weekly HR shifted over the time. This was probably due to a different food distribution in the two seasons: in winter, food resources were mainly available in thermophilous wood (acorns), while in spring they were more scattered and diversified (elm and maple samaras, coniferous pollen, oak catkins). Since dormice exploited ephemeral food resources, patchily distributed in time and space, their activity within the home ranges was highly concentrated in a few small discrete patches. In particular, the core areas used by females were smaller (11.7 %) than those used by males (17 %). The total distance travelled per night was greater in winter (265.56 ± 28.21 m) than in spring (161.61 ± 8.8 m). This could depend on the longer duration of the night in winter but also on the need to reach the thermophilous deciduous patches where acorns were abundant. On the other hand, no difference were observed between the distance travelled by the two sexes (♀ = 200.33 ± 17.31 m; ♂ = 189.78 ± 14.7 m). In general, our results suggested that spacing behaviour did not differ between sexes. This may be explained by the high habitat patchiness and diversity that could in