THE EFFECTS OF FOREST FRAGMENTATION ON BUTTERFLY COMMUNITIES IN CENTRAL SPAIN

We studied butterfly communities of isolated woodlots (3.6-2115 ha) in central Spain during 1991 to investigate the influence of area, shape, isolation and habitat on community structure. A total of eighty-one species was observed. Butterfly diversity, rather than species number, was significantly correlated with both woodland area and isolation (area of woodland within 1 km of the study plots). Rounded rather than long thin fragments are, apparently, advantageous for the maintenance of butterfly diversity. Species diversity increases as patchiness of forest fragments increases. A measure of rare and interesting communities in an European context, Kudrna's (1986) chorological index, decreases with area, presumably as a consequence of habitat changes (area affects habitat structure). These results may generate contradictory decisions in relation to butterfly species conversation.