Vegetation biomass and topography are associated with seasonal habitat selection and fall translocation behavior in Arctic hares

TL;DR

Arctic hares on Ellesmere Island select different habitats in summer and winter, and their fall movements are influenced by vegetation and terrain features.

Contribution

This study provides new insights into seasonal habitat selection and long-distance movements in a phylogenetically distinct species, Arctic hares.

Findings

Arctic hares selected low elevation in summer and high elevation with high vegetation biomass in winter.

During fall relocation, hares alternated between stopover and traveling states, with stopovers in areas of higher vegetation heterogeneity.

Vegetation biomass and elevation interacted to influence stopover locations during fall translocation.

Abstract

Habitat selection theory suggests that environmental features selected at coarse scales reveal fundamental factors affecting animal fitness. When these factors vary across seasons, they may lead to large-scale movements, including long-distance seasonal migrations. We analyzed the seasonal habitat selection of 25 satellite-tracked Arctic hares from a population on Ellesmere Island (Nunavut, Canada) that relocated over 100 km in the fall. Since no other lagomorph is known to perform such extensive movements, this population offered an ideal setting to test animal movement and habitat selection theory. On summer grounds hares selected low elevation areas, while on winter grounds they selected high vegetation biomass, high elevation, and steep slopes. During fall relocation, they alternated between stopover and traveling behavioral states (ratio 2:1). Stopover locations were characterized by higher vegetation heterogeneity and lower rugosity than traveling locations, while vegetation biomass and elevation interacted to explain stopover locations in a more complex way. The selected combination of environmental features thus varied across seasons and behavioral states, in a way broadly consistent with predictions based on the changing food and safety needs of hares. Although causality was not demonstrated, our results improve our understanding of long-distance movements and habitat selection in Arctic hares, as well as herbivore ecology in the polar desert. Results also provide strong support to animal movement and habitat selection theory, by showing how some important hypotheses hold when tested in a species phylogenetically distinct from most animal models used in this research field.

The online version contains supplementary material available at 10.1007/s00442-024-05534-x.

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