Long-term population dynamics of small mammals in southern taiga of Vetluga River basin

The population dynamics of the bank vole, Clethrionomys, the northern red-b acked vole, Ch. rutilus, the common shrew, Sorex araneus, and the Laxmann's shrew, S. caecutiens, has been studied for 18 years in Manturovo raion of Kostroma oblast (Russia). All four populations are shown to be not cyclic. The intervals between the density peaks are irregular and range from 2 to 7 years. The positive correlation between the densities of related species ( 2 species of voles and 2 species of shrews) confirms the synchronism in the ir population dynamics. The mean density level per season correlated positi vely with the thickness of the snow cover and negatively with snow density. This correlation is tighter for shrews than for voles.