Dispersion of the bank vole in fine- and coarse-grained mosaics of deciduous and mixed coniferous forests

Density and distribution of the bank vole Clethrionomys gtareolus (Schreber, 1780) was studied in 1986-1989 on two forest plots (one of 5.4 and one of 5.8 ha) that differed with respect to their mosaic character. On both plots densities of bank voles were similar in different habitats. The same trap sites were used by voles in a similar way in successive study years. Spatial variations in habitat use were primarily related to the density of plant cover and its spatial distribution providing shelter from predators. Frequency and intensity of use of trap sites by voles was positively corre­lated with the percent cover of shrubs and tall herbaceous plants. It was negatively correlated with the percent area without herb cover and with the percent cover of photophilous herbs. Using the correlation method, it was possible to estimate the effect of a given environmental factor on the distribution of bank voles only when the range of spatial variation of this factor was large.