INFLUENCES OF AREA, ISOLATION AND HABITAT FEATURES ON DISTRIBUTION OFSNAKES IN MEDITERRANEAN FRAGMENTED WOODLANDS

The effects of isolation-related and vegetational parameters on presen ce and relative abundance of snakes in patchy forested fragments of Me diterranean central Italy are studied. The most abundant species was C oluber viridiflavus (accounting for 47.7% of the total snake sample ob served) followed by Vipera aspis (22%), Elaphe longissima (21.5%), Nat rix natrix (7.7%), and Coronella austriaca (1.1%). There was a clear t rend for bigger species to be less distributed among the various fores t fragments than the smaller species. Presence of Coluber viridiflavus , Coronella austriaca and Natrix natrix was not influenced by woodland area, whereas that of Vipera aspis and Elaphe longissima was positive ly influenced by woodland area. Woodland isolation parameters did not influence the presence of Coluber viridiflavus, Coronella austriaca an d Natrix natrix, but of Vipera aspis and Elaphe longissima. Discrimina nt stepwise analysis suggested that specific environmental features in fluenced the occurrence and abundance of the various snake species, Vi pera aspis being the taxon more affected by isolation-related paramete rs. Some conservation implications of our observations are also discus sed.