DISTRIBUTION AND ABUNDANCE OF BUTTERFLIES IN A MOUNTAIN AREA IN THE NORTHERN IBERIAN PENINSULA

The effect of altitudinal range, distance to the latitudinal boundary of geographical range, body size and larval food plant on both the dis tribution and abundance of butterflies have been studied in a mountain area along a marked altitudinal gradient. Multiple regression analysi s revealed that distribution was positively related to altitudinal ran ge and abundance. Altitudinal range accounted for a great part of vari ance in species distribution. Altitudinal range increased as both dist ance to latitudinal boundary of geographical range and body size incre ased. Abundance was not affected by altitudinal range, body size or di stance to latitudinal boundary. Larval food plants family was related to the abundance of butterflies, but not to distribution or altitudina l range. These results suggest that regional distributions of butterfl ies are likely to be limited by climatic tolerances of species, while local abundance might be influenced by local resource levels.