Small Mammal Populations in Woodlot Islands

Abstract

Ten woodlot islands (surrounded by cornfields) which varied in size and isolation were compared with mainland habitats (forests over 30 ha in area) to test predictions of MacArthur and Wilson''s model of island biogeography. Mainland communities contained significantly more small mammal species in higher densities than did the islands. The number of species on an island was positively related to its size. Islands contained significantly lower densities of Peromyscus leucopus than mainlands, although the sex ratios and age ratios did not differe significantly. Density of P. leucopus on islands was inversely related to isolation. Small isolated islands were usually populated by few subadult males. No relationship was found between island isolation or size and wt of P. leucopus. The study supports several predictions of the MacArthur and Wilson model.