To rest or to roam: Functional habitat use of an insectivorous bat species during active and resting behavior

As vital players in many terrestrial ecosystems, insectivorous bats in Europe are of high conservation priority and protected by international law. However, ongoing human expansion and land-use change have profoundly altered their habitats, and understanding their habitat use is essential for effective conservation planning. Nevertheless, behavioral states, particularly night resting, are rarely considered when quantifying habitat use. This study presents the first GPS-tracking-based quantitative assessment of habitat use in the pond bat ( Myotis dasycneme ), a vulnerable water-trawling specialist, across distinct active and resting behaviors while away from the roost. Combining high-resolution GPS tracking with tri-axial accelerometry, we distinguished active (foraging and commuting) from resting states and used generalized linear mixed models to examine their functional habitat use in relation to relevant land cover types and landscape metrics. We found that pond bats spent a substantial amount of nighttime resting between active bouts, with over half of resting occurring outside buildings. They used diverse, simple-shaped freshwater bodies and riparian areas to support active behaviors and consistently avoided cultivated land, whereas they relied on mosaics of open and closed vegetation, primarily forest edges and isolated trees close to foraging water bodies, to facilitate non-building night resting. Conservation of pond bats requires maintaining foraging habitats (e.g., diverse water bodies with riparian vegetation) and commuting features (e.g., regular-shaped water banks), while preserving or providing landscape-specific night-resting structures near foraging areas. Integrating behavior-specific habitat use, especially night-resting sites, is crucial for effective bat conservation and targeted landscape management. • We use state-of-the-art tracking to quantify functional habitat use of the pond bat • Pond bats use simple-shaped waterbodies with high edge density during active states • They spend much of the night resting on forest edges and isolated trees near water • We stress designing dedicated habitats to support diverse behavioral needs • Conservation science should consider functional habitats at multiple spatial scales