OCCUPANCY OF ISOLATED WOODLOTS BY THE RED SQUIRREL SCIURUS-VULGARIS L IN ITALY

Effects of habitat fragmentation on the pattern of occupancy by the red squirrel Sciurus vulgaris were investigated in 46 isolated oakwoods in the Po Plain and 34 in the Apennines, where habitat structure variables were also measured. Presence of the red squirrel was detected by the presence of dreys. Logistic regression analysis showed that only woodlot size in the Apennines and distance from the nearest 'source-area' in the Po Plain influenced the presence of the species. No habitat structure variable improved the models in the Apennines. Interdependent dynamics of patches and a 'source-sink' structure are suggested for the Apennine and the Po Plain study areas, respectively. In more isolated woodlots in the Po Plain short-term extinctions are likely to occur.