DISPERSION OF THE BANK VOLE IN FINE-GRAINED AND COARSE-GRAINED MOSAICS OF DECIDUOUS AND MIXED CONIFEROUS FORESTS

Density and distribution of the bank vole Clethrionomys glareolus (Sch reber, 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 characte r. On both plots densities of bank voles were similar in different hab itats. The same trap sites were used by voles in a similar way in succ essive study years. Spatial variations in habitat use were primarily r elated to the density of plant cover and its spatial distribution prov iding shelter from predators. Frequency and intensity of use of trap s ites by voles was positively correlated with the percent cover of shru bs and tall herbaceous plants. It was negatively correlated with the p ercent area without herb cover and with the percent cover of photophil ous herbs. Using the correlation method, it was possible to estimate t he effect of a given environmental factor on the distribution of bank voles only when the range of spatial variation of this factor was larg e.