Long-term dynamics of biotopical distribution of a common shrew (Sorex araneus, Linnaeus 1758) in Karelian mosaic landscape

The dynamics of the number of common shrew and its biotopical distribution in the middle-taiga ecosystems of Southern Karelia (Kondopozhsky region, village of Gomselga) has been studied from 1994 to 2014. Altogether, 60559 traps-days were worked out, 1532 of common shrew species were trapped. As a result of maps’ interpretation and space photographs based on the type of vegetation (middle and high resolution), electronic GIS-maps of 10 types of habitat for 14 time slices (1960, 1970, 1973, 1975, 1984, 1986, 1989, 2001, 2003, 2005, 2009, 2013) were obtained. The dynamics of vegetation cover is expressed in the increase of the area of anthropogenic habitats (cutting of different ages) and significant decrease in the area of natural forest habitats. Trapping indicates that during warm period of the year the number of common shrew is usually higher in anthropogenic habitats than in forest ones; however, in winter and spring the survival of animals, in contrast, is significantly higher in mature forests. Long-term dynamics of shrew population consists in increasing the overall number of forest habitats and reducing that of anthropogenic ones. In general, the size of shrew population in a local area is defined by the ratio between the area of natural and anthropogenic habitats. They differ in the conditions of habitation and the vectors of reproduction and survival of common shrew are directed oppositely.