Winter herbivory by voles during a population peak: the relative importance of local factors and landscape pattern

摘要: 1.  We studied the relative role of local habitat variables and landscape pattern on vole–plant interactions in a system with grey-sided voles (Clethrionomys rufocanus (Sund.)) their favourite winter food plant, bilberry (Vaccinium myrtillus L.). The study was conducted during vole peak year (1992–93) tundra area northern Norway. 2.  Using Mantel statistics we were able to separate direct effects spatial patterning habitats indirect due aggregations similar habitats. 3.  Results indicate that knowledge about explicit patches does not improve our understanding system. Instead, two factors, vegetation height biomass, explained more than 50% variation cutting intensity (defined as proportion above-ground shoots cut). Increasing increased, increasing biomass decreased, intensity. 4.  The conclusion are distribute themselves quality also partially supported by estimated over-winter persistence various habitats. Vole uncorrelated height, important predictor autumn density, but tended correlate deviation from relation between density. This conforms expectations theory ideal-free distribution. 5.  The cue for choice, i.e. indicates either predation or freezing risk is when selecting over-wintering habitat.