Habitat selection by roe deer and sheep: does habitat ranking reflect resource availability?

摘要

Habitat ranking is often assumed to reflect feed availability, but habitat selection may involve trade-offs, for example, between selecting for feed or cover. Habitat selection of 27 radio-collared European roe deer (Capreolus capreolus) and 10 free-ranging domestic sheep (Ovis aries) on a forest range in southern Norway was studied in relation to resource availability. It was predicted that ruminants of different feeding types would use habitats according to the main forage class, but that anti-predator behaviour might remove the correlation between habitat selection and feed availability, thus making temporal and spatial scaling crucial. As predicted, habitat selection by sheep was highly correlated with grass availability on the home-range andstudy-area scales. The habitat ranking of roe deer habitat selection did not correlate with the availability of herbs on either scale, but rather was correlated with the availability of canopy cover. There was a clear effect of temporal scale on habitatselection by roe deer. During summer, roe deer used forest habitats with more forage to a greater extent when they were active than when they were inactive, and tended to use habitats with greater availability of herbs at night. It is concluded that scale-dependent trade-offs in habitat selection may cause inconsistent habitat rankings when pooled across temporal and spatial scales.