HABITAT SELECTION IN THE EURASIAN RED SQUIRREL, SCIURUS-VULGARIS, IN RELATION TO FOREST FRAGMENTATION

A population of Eurasian red squirrels (Sciurus vulgaris) in south-central Sweden showed a strong preference for forest older than 35 years and with more than 25% Norway spruce (Picea abies). This preferred habitat constituted 24% of the study area. The proportion of avoided habitats was 30%, and the remaining 46% could be described as used but not preferred habitats. Given these proportions, the squirrels can be shown theoretically to be able to reach all preferred patches by moving across the used, although not preferred habitat patches, or within the preferred ones. Males had larger home ranges (mean 121.6 ha) than females (mean 23.0 ha). Mean daily movement was 430 m for males and 180 m for females; the maximum movement was 2800 m for males and 680 m for females. Most of the preferred habitat occurred in fragments larger than the area requirement of an individual squirrel, and even the most isolated fragments were within a trivial range for squirrels. Therefore, we predict that the random sample hypothesis will give a good prediction of the effects of forest fragmentation on the red squirrel in this landscape. However, if the proportion of avoided habitats increases, isolation and fragment size might affect the population density of red squirrels and the population size would be smaller than predicted from the random sample hypothesis.