HABITAT OCCURRENCE AND PREY DISTRIBUTION OF A MULTISPECIES COMMUNITY OF SHREWS IN THE SIBERIAN TAIGA

The habitat occurrence and invertebrate prey distribution of nine spec ies of shrew in the mid-taiga of central Siberia were investigated. Sp ecies richness ranged from 4-9 shrews per habitat. Sorer araneus and S . caecutiens were numerically dominant in all seven habitats (44 and 3 6% of the total catch, respectively) while So, ex minutus, S. tundrens is, S. isodon, and S. roboratus each constituted 4-6% and Sorex minuti ssimus, S. daphaenodon, and Neomys fodiens were rare (< 1% each). Ther e was no overall correlation between abundance of shrews and invertebr ate prey, but hood-plain habitats supported the greatest abundance and species richness of shrews, and high density and biomass of prey. Oli gochaete-eating shrews were twice as numerous here as in other habitat s, coincident with high abundance of oligochaetes. The large, earthwor m-feeding Sorer roboratus occurred only here. The more acid, typical t aiga habitats had lower adundance and species richness of shrews. They had the lowest density and biomass of prey, particularly oligochaetes , and far fewer oligochaete-eating shrews. The relative paucity of shr ews in bush-meadow habitats, despite abundant prey, implied that habit at structure influences shrew distribution. Differential numbers of ce rtain species in the presence or absence of larger congeners also sugg ested that interspecific competitive effects influence habitat selecti on by shrews. The high species richness of shrews here in the mid-taig a may be accounted for by the heterogeneous nature of the constituent habitats which provide niches for small and large species of shrew wit h a range of feeding habits.