Duško Ćirović, Slaven Reljić, Neda Bogdanović, Ilija Pantelić, Djuro Huber, Goran Gužvica, Lidija Šver, Ratko Popović, Haris Hadžihajdarević, Marija Iković, Igor Stojović, Aleksandar Perović, Dražen Kotrošan,, Mirko Šarac, Josipa Šimić, Lorenzo Bernicchi, Lorenzo Frangini, Sara Vezzaro, Virginia Barca

Brown bear (Ursus arctos) habitat management often lacks quantitative assessments of the functional value of different environments as refuge or foraging areas. Specifically, the energetic costs associated with habitat use and activity intensity are frequently overlooked. Within the framework of the Interreg IPA Adrion 4Pethabeco project, this study aimed to investigate activity rhythms and behavioral patterns to estimate the energetic costs and functional significance of habitats (e.g., foraging vs. refuge).
Data were collected from 14 bears equipped with Vectronic GPS-accelerometer collars in the Alpine region (Italy) and the Dinaric-Balkan region (Croatia and Serbia). Accelerometer data were analyzed on an hourly basis and categorized into three behavioral states: resting, foraging, and moving. Energetic costs were assigned to each category and subsequently linked to specific habitat types. Results show that bears in the Alpine region exhibited significantly higher average activity levels (+33%) compared to those in the Dinaric-Balkan areas. These differences correspond to distinct behavioral patterns: Alpine bears spent less time resting (-10%) and more time foraging (+36%) and traveling (+43%) than their Dinaric-Balkan counterparts. Consequently, the estimated energetic cost of activity was 14% higher for bears in the Alpine area.
Different habitats displayed clear functional roles, with specific selection patterns for refuge, foraging, or movement. This work provides a critical foundation for habitat management by aligning the biological requirements of the species with the energetic and functional value of the landscape.