Spatial and temporal patterns of human avoidance by brown bears in a reintroduced population
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MUSE - Science Museum, Corso del Lavoro e della Scienza 3, 38122 Trento, Italy
National Research Council Institute of Marine Sciences (CNR-ISMAR), Arsenale, Tesa 104, Castello 2737/F, 30122 Venezia, Italy
Department of Biology, University of Florence, Via Madonna del Piano 6, 50019 Sesto Fiorentino, Italy
Valentina Oberosler   

MUSE - Science Museum, Corso del Lavoro e della Scienza 3, 38122 Trento, Italy
Publication date: 2020-12-21
Hystrix It. J. Mamm. 2020;31(2)
The preservation of large carnivores is a formidable challenge for biodiversity conservation in Europe, where few areas can be considered wilderness. In this context, brown bears Ursus arctos in Europe coexist with people in densely settled, multi-use landscapes and hence have to cope with diffuse human activities. This calls for robust knowledge on the effects that such activities have on brown bear distribution and behaviour. We sampled 220 km2 with 60 camera trap locations over four consecutive years to investigate the effect of human activity and settlements on brown bear spatial and temporal patterns across the core area of the reintroduced population in the central Italian Alps. By using images of people and vehicles to quantify human activity at camera trap sites we could directly study how humans affect bears’ activity and occupancy. We assessed bear’s daily patterns and found a predominantly crepuscular and nocturnal behaviour, with peaks of activity before dawn and after dusk. We also modelled bear occurrence and detection probability around the dawn and dusk hours only, i.e., when the likelihood of encounters with humans was highest. Results showed that proximity to settlements and anthropogenic traffic, especially motorised, significantly and negatively influenced bear occupancy rates across the study area. Pedestrian and motorised traffic rates were both also negatively related to detection probability. By using four years of data and a refined modelling approach that considered the hours of maximum activity overlap of humans and bears, our results extend the findings from an initial study by suggesting that human presence induces not only temporal, but also spatial displacement. These findings are consistent with evidence from other populations that bears living in human-modified landscapes adapt their spatio-temporal patterns to avoid humans, an important prerequisite for the coexistence of bears and people in complex human-natural landscapes.
We thank the Forest and Wildlife Service of the Autonomous Province of Trento, and particularly Claudio Groff, for the fruitful collaboration offered for the study. We also thank the Adamello-Brenta Natural Park. Funding came from the Autonomous Province of Trento through a formal agreement with MUSE - Museo delle Scienze, and we thank Paolo Pedrini for facilitating the agreement implementation. We are grateful to the following staff of these institutions and volunteers for their help in the field: Enrico Dorigatti, Riccardo Dorna, Alessandro Franceschini, Marzia Pin, Renato Rizzoli, Stefania Truschi, Massimo Vettorazzi, Gilberto Volcan, Matteo Zeni, Michele Zeni. Elise Zipkin kindly provided statistical advice during the analyses. Finally, we are grateful to the handling editor and two anonymous reviewers for constructive comments on an earlier version of the manuscript.