Communities of small mammals in six biotopes of northern Italy

Spatial relationships and microhabitat selection were studied in syntopic populations of small mammals. Four hundred three individuals of 7 species (Sorex araneus, Sorex minutus, Crocidura suaveolens, Crocidura leucodon, Clethrionomys glareolus, Apodemus sylvaticus, Mus musculus) were trapped in six north Italian biotopes, between June 1988 and September 1989. The wood mouse was present in all biotopes and was, numerically, the dominant species; the bank vole was the second most abundant species. Habitat preferences were similar to those reported for northern Europe but the bank vole was also present in habitats other than ancient woodlands, Community diversity and richness were positively correlated with habitat structural diversity. The species selected micro- habitats that were significantly different from those available; ground cover at arboreal and grass level and litter structure were generally the most important variables. There were significant differences in mcrohabitat use among dominant species; the intensity of segregation was higher in mature woodland and alder grove than in the other biotopes, which may reflect their different management.