Habitat preferences of four sympatric species of shrews

Abstract

Habitat preferences were studied in a shrew community of two semiaquatic species, Neomys anomalus Cabrera, 1907 and N. fodiens (Pennant, 1771), and two terrestrial species, Sorex araneus Linnaeus, 1758 and S. minutus Linnaeus, 1766, in a study area (5600 m2) alongside a small stream in Bialowieza Forest (E Poland). Preferences were estimated by relating frequency of captures with macro- and microhabitat characteristics of trapping points. Distance to the stream and ground wetness appeared to be more important than macrohabitat and plant cover in separation of habitat niches. N. fodiens was trapped at places significantly wetter and closer to the stream than the three other species, N. anomalus was captured at places wetter and closer to the stream than S. araneus and S. minutus was trapped closer to the stream than S. araneus. Habitat preferences of these species reflected vertical segregation in their foraging. The inter-specific overlaps in habitat preferences were lowest between N. fodiens and the two Sorex species and highest between N. anomalus and S. araneus and between the two Sorex species. An inverse relationship between the breadths of the trophic and habitat niches of the shrews appeared: the greatest trophic specialist S. minutus had the broadest habitat niche, whereas the greatest trophic generalist N. fodiens had the narrowest habitat niche. High interspecific overlaps in habitat preferences and little overlaps in spatial distribution suggest that the separation of ecological niches of these four species in the study site reflects other mechanisms in addition to habitat preferences.