Consumption of Bark and Seeds by Voles in Relation to Habitat and Landscape Structure

Abstract

Voles cause damage in forestry by eating the bark of seedlings and the seeds of conifers. Folivorous field voles ( Microtus agrestis ), restricted to various types of grassland, are mainly responsible for damage to bark, and granivorous bank voles ( Clethrionomys glareolus ), supported by most forest environments, for the consumption of seeds. Densities of bank and field voles, consumption of bark on indigenous and experimental woody plants, and consumption of experimentally supplied seeds were measured during the vole cycle 1997-2000 in relation to three habitat and three landscape variables. Landscape variables explained field vole densities and consumption of bark to a considerable extent, while habitat variables were more adequate for densities of bank vole and consumption of seeds. Field vole populations may demonstrate a ''mass effect'', where the success of early development and dispersal from subpopulations will decide peak numbers over entire landscapes. Numbers of field voles may affect numbers of the inferior bank vole. Thus, predicting the exact location of vole damage is principally difficult.