The seasonal trade-off between food and cover in the Alpine mountain hare (Lepus timidus)

Abstract

Habitat use of prey species is often subjected to strong trade-offs when foraging needs and predator avoidance cannot be met simultaneously. Trade-offs may be particularly pronounced for species dwelling above ground throughout the year. Identifying habitat use of such species may help to determine crucial and limited environmental resources and has strong implications for habitat management. We investigated the relative importance of habitat structure and composition for mountain hares in the Swiss Alps at the small scale for two time periods, throughout the year and during the reproductive period. Habitat use was assessed by a non-invasive approach that considers the spatio-temporal distribution of fecal pellets, sampled along systematically distributed transects. We found that heterogeneous habitats with high diversity of vegetation layers and/or abundance of saplings and storeyed vegetation structures are strongly used. The availability of shelter was more important in summer when hares strongly used dense habitats that offered protection from predators. The availability of food was more important as predictor for year-round use compared to the reproductive period when food is overabundant for hares. A heterogeneous habitat provides an optimal distribution and availability of shelter and food resources and allows the hare to adjust its activity pattern to changing environmental conditions. Therefore, the occurrence of a structurally heterogeneous ecotone at the upper timber line with a mosaic of different vegetation types and hiding structures should be considered in the management of the species.