Research on arboreal mammals living in Mediterranean forests is poor. Molecular research assessed the existence of an evolutionary significant unit in the edible dormouse populations living in south Italy, Sicily and Sardinia, and we decided to investigate the environmental factors capable of explaining its occurrence and abundance in Sicily, for a better management of these populations. We assessed the species habitat preferences by setting 25 large and 25 small nestboxes in five sample areas along an altitudinal gradient of the Madonie Range, and recorded habitat variables, food availability, and demographic data for two years. To obtain synthetic descriptors of the dormice habitat requirements, we extracted uncorrelated linear combinations of original variables by Principal Component Analysis; then we modelled habitat preferences of dormice by Generalized Linear Models, and selected the best models by Akaike's information criterion and model averaging. Dormice abundances varied markedly between the two years of study. Population peaked and reproduced in 2010, a masting year of oaks and beeches. In the following non-masting year, a much lower number of adults and yearlings used nestboxes, without any sign of reproduction. In both years we found a significant effect of altitudinal vegetation belt. Dormice seem to prefer mixed broad-leaved and evergreen (cork, holm) oak forests below 800-1300 m a.s.l, to beech forests at higher altitude, and avoid coniferous plantations. Inside these woodlands they seem to prefer monotypic and mature oak-stands with dense canopies. Large nestboxes are more preferred than small ones only during reproductive years. Protection of large and mature woodland from wildfires and forestry management caring the retention of significant elements like old trees, logs and litter mounds are necessary to maintain the habitat of edible dormouse in Southern Mediterranean forests. Artificial nestboxes are a viable device to help population restocking in degraded forests.
In fast changing landscapes, modelling environmentspecies relationships is one of the main goals of ecological research aiming at a balance between conservation and the increasing demand of natural resources (Rushton et al. 2004). Habitat preference and distribution models referred to appropriate spatial-scales, are increasingly being used to address a wide range of questions in ecology and conservation (Lehmann et al. 2002, Araújo & Guisan 2006), like primary information for identification of conservation hotspots (Ortega-Huerta & Peterson 2004), regional conservation planning and reserve design (Li et al. 1997, Özesmi & Mitsch 1997, Mace et al. 1999). Major goal of such modelling is to search for anthropogenic drivers (e.g. deforestation, land use change), abiotic (e.g. topography, climate) factors, biotic interactions (e.g. dispersal or competition), as well as historical and contingent factors that shape species distributions; aiming at the selection of the “best” model for each species in terms of predictive accuracy (e.g. Pearce et al. 2001, Cabeza et al. 2004, Claridge et al. 2008, López-Iborra et al. 2011). Studies modelling the habitat preference of species commonly follow a correlative approach based on multiple regression methods (e.g. Generalized Linear Models) to combine species' occurrence data with environmental conditions where a species is known to be present or absent and then to build a representation of a species' ecological requirements (Guisan & Zimmermann 2000, Bolker et al. 2009, Franklin 2009). The information theoretic (IT) approach represents the most recent advance in this field (Grueber et al. 2011).
Often authors refer to habitat selection and habitat preference as they were equivalent (e.g. Berg & Berg 1998, Suárez-Seoane et al. 2002, Jeganathan et al. 2004). We prefer to make a distinction between habitat selection, the behavioural process with which individuals choose resources, and habitat preference, i.e. the final pattern of habitats used with respect to their availability (Manly et al. 2002, Martínez et al. 2003). In addition, habitat preferences have been assumed to be adaptive (Martin 1998), as they involve a hierarchical discrimination of environmental features that provide the use of different pattern of resources, which in turn affect survival and reproduction of animal species. We therefore referred our research in terms of habitat preference, because we aimed to determine the habitat features on which the settlement of our focal species (the edible dormouse, Glis glis) depends in a Mediterranean forest, and whether habitat requirements are the same between different age cohorts of individuals.
The phylogeography of glirids (Hürner et al. 2010, Lo Brutto et al. 2011, Mouton et al. 2012, Perez et al. 2013) has been recently analysed in the Palaearctic by mitochondrial DNA analyses. Results on edible dormouse (Hürner et al. 2010) have revealed two different lineages, namely the European and Italian lineage. A further analysis on nuclear DNA (Hürner et al. in lit.) has definitely confirmed the genetic separation of the South Italian population (Calabria, Eolian islands, Sardinia and Sicily), therefore supporting the validity of the G. g. italicu