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

Effects of habitat fragmentation on the pattern of occupancy by the re d squirrel Sciurus vulgaris were investigated in 46 isolated oakwoods in the Po Plain and 34 in the Apennines, where habitat structure varia bles were also measured. Presence of the red squirrel was detected by the presence of dreys. Logistic regression analysis showed that only w oodlot size in the Apennines and distance from the nearest 'source-are a' in the Po Plain influenced the presence of the species. No habitat structure variable improved the models in the Apennines. Interdependen t dynamics of patches and a 'source-sink' structure are suggested for the Apennine and the Po Plain study areas, respectively. In more isola ted woodlots in the Po Plain short-term extinctions are likely to occu r.