Terrestrial Gastropods of South Fox Island, Leelanau Co., Michigan, U.S.A.

Abstract: Despite the existence of more than 565 islands in the upper three United States Great Lakes, land snails have been reported from only about 1% of them. This first publication about land snails of any island in eastern Lake Michigan reports on the 38 species (10,162 individuals) of land snails we found on South Fox Island. We examined leaf litter samples collected from 14 localities on South Fox Island in the years 1993 and 1997. We provide identification notes and habitat notes (beech-maple forest, cedar forest, meadow) for each of the species. The number of species, 38, on South Fox Island is about average when compared to the number of species from six other islands in the upper three Great Lakes that have had comparable sampling intensity. We report the northernmost published localities for two minute snails, Carychium nannodes G.H. Clapp, 1905 and Striatura meridionalis (Pilsbry and Ferriss, 1906), and one of the northernmost localities for the minute snail Guppya sterkii (Dall, 1888). The absence of two larger species that are present on the adjacent mainland is consistent with our hypothesis that the sequences of glacial history, island development, and northward snail colonization have influenced modern distributions of snails.