Brown bear den characteristics and selection in eastern Transylvania, Romania

Ulysse Faure (1) , Csaba Domokos (2) , Agathe Leriche (3) , Bogdan Cristescu (4, 5)

1 Faculté des Sciences et Techniques de Saint Jérôme
2 Milvus Group Bird and Nature Protection Association
3 IMBE - Institut méditerranéen de biodiversité et d'écologie marine et continentale
4 University of Alberta
5 Institute for Communities and Wildlife in Africa (iCWild), Department of Biological Sciences, University of Cape Town

Dens are important for species that need to survive and reproduce during harsh winters. Brown bears (Ursus arctos) in Romania, listed by the European Union as a population of concern, use dens for several months each year. To date, few quantitative assessments of denning habitat have been carried out for this population or others in Europe. In 2008-2013 and 2015-2017, we used local knowledge and telemetry data from brown bears fitted with GPS collars to identify 115 winter dens and eight open ground nests used by bears in eastern Transylvania, Romania. We located most dens in mountainous areas (64%) and fewer in foothills (36%). Den entrances in mountainous areas were significantly narrower than entrances in foothills, likely due to the need for reduced thermal loss during more severe winters at higher elevations. We selected seven habitat characteristics (abiotic and biotic) and human-related covariates associated with known locations of dens and open nests to identify potential brown bear denning habitat using maximum entropy modeling. We found that terrain ruggedness was the single most important factor when predicting bear denning habitat. The habitat map derived from this study can be used in the future to safeguard bear denning areas from potential human disturbances.

Keywords: bear conservation; disturbance ecology; habitat ecology; MaxEnt; topography; Ursidae

Domains: Environmental Sciences

Ulysse Faure, Csaba Domokos, Agathe Leriche, Bogdan Cristescu. Brown bear den characteristics and selection in eastern Transylvania, Romania. Journal of Mammalogy, 2020, 101 (4), pp.1177-1188. ⟨10.1093/jmammal/gyaa047⟩. ⟨hal-03093764⟩