Deer density drives habitat use of establishing wolves in the Western European Alps

• Main Authors: Roder, Stefanie, Biollaz, François, Mettaz, Stéphane, Zimmermann, Fridolin, Manz, Ralph, Kery, Marc, Vignali, Sergio, Fumagalli, Luca, Arlettaz, Raphaël, Braunisch, Veronika
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2020
• Subjects: Canis lupus; habitat modelling; MaxEnt; Predator-prey relationships; Ungulate density; wolf; Recolonization by carnivores
• Online Access: https://doi.org/10.5061/dryad.2v6wwpzhx

1. The return of top carnivores to their historical range triggers conflicts with the interests of different stakeholder groups. Anticipating such conflicts is key to appropriate conservation management, which calls for reliable spatial predictions of future carnivore occurrence. Previous models have assessed general habitat suitability for wolves, but the factors driving the settlement of dispersing individuals remain ill-understood. In particular, little attention has been paid to the role of prey availability in the recolonization process. 2. High-spatial-resolution, area-wide relative densities of the wolf's main ungulate prey species (red deer, roe deer and chamois) were assessed from snow-track surveys and modelled along with wolf presence data and other environmental descriptors to identify the main drivers of habitat selection of re-establishing wolves in the Western European Alps. 3. Prey species abundance was estimated from the minimum number of individuals recorded from snow-tracks along 218 1km transects surveyed twice a year during four successive winters (2012/13–2015/16). Abundance estimates per transect, corrected for species-specific detection probabilities and averaged across winters, were used to model area-wide relative prey density and biomass. 4. Confirmed wolf observations during the same four winters were used to develop a spatially-explicit habitat selection model for establishing wolves, based on our estimates of prey supply and other environmental descriptors of topography, land-use and climate. 5. Detection-corrected ungulate prey abundances and modelled relative densities varied considerably in space (0–2.8, 1.3–4.5 and 0–6.3 per 50ha in red deer, roe deer and chamois, respectively; 1.3–11.65 pooled), while total predicted prey biomass ranged from 23–304kg per 50ha. 6. Red deer density was the most important factor explaining wolf occurrence (31% contribution), followed by roe deer density (22%), winter precipitation (19%) and presence of game reserves (16%), showing that food ...