Determinants and patterns of the endangered brown bear Ursus arctos habitat use in the French Pyrenees revealed by occupancy modeling

The Pyrenean brown bear (Ursus arctos) in the mountainous border between France and Spain is one of the smallest and most endangered populations of large carnivores in Europe. Here, we aimed at assessing trends in brown bear habitat use in the Pyrenees and determining the underlying environmental and anthropogenic drivers. Using detection/non-detection data collected between 2008 and 2014 through non-invasive methods, we developed occupancy models to investigate the dynamic of brown bear habitat use in the Pyrenees accounting for local colonization and extinction processes. First, we found two non-connected occupancy cores, one located in the West and another in the Center of the Pyrenees, with an overall significant decrease in habitat use between 2008 and 2014. Second, we showed a negative correlation between human density and bear occupancy in agreement with previous studies on brown bear habitat suitability. Our results confirm the critically endangered status of the Pyrenean population of brown bears.