Taiga shrew (Sorex isodon, Eulipotyphla) in the North-East of the European Russia: Distribution, habitats and abundance

The materials of our studies on the taiga shrew ( Sorex isodon Turov, 1924) in the NorthEast of the European Russia, a poorly studied species of small mammals of the region, are summarized. Its distribution is shown to generally coincide with the northern border of the taiga zone. The optimal biotopes are grass spruce forests (only for them the values of the biotope fidelity coefficient are positive). The numbers of taiga shrews in lowland localities are 0–2.4 individuals, in foothill habitats it increases up to 4.4–8.6 individuals and reaches maximum values on the western slope of the Northern Urals (28 individuals per 100 cone-nigths). The formation of the numbers of the species is much influenced by the landscape conditions of the territory: the ratio of habitat types and their areas. An increase in the area of grass forests leads to an increase in the abundance of taiga shrews.