Spatial and temporal patterns of human avoidance by brown bears in a reintroduced population

The preservation of large carnivores is a formidable challenge for biodiversity conservation in Eu-rope, 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 be-fore 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.