Conservation implications of range dynamics in endangered populations: An example with brown bears

Abstract

AbstractMonitoring changes in the status of threatened and endangered species is critical for conservation, especially when these changes can be more dynamic than management actions. We studied how the range of the endangered Cantabrian brown bear (Ursus arctos) population has recovered after a long period of decrease. We estimated the presence range (using all available data on bear presence) and the breeding range (using data on females with cubs presence) in: 1982–1992, 1993–2002, and 2003–2012; to analyze temporal dynamics in the spatial extension of these ranges between periods. For the presence range, we observed an initial reduction of 25% between the first two periods maintaining two isolated subpopulations, followed by an increase of 70% in the third period that merged the subpopulations into a single population. The breeding range represented about 50% of the presence range and was stable between the two first periods and increased by 30% in the last period. Despite that increase two spatial breeding cores remained separated across all periods. Generalized linear models analyzing the factors affecting extinction and colonization between periods showed that bears expanded to areas closer to the center of the population and with low human disturbance. Our model projection predicted correctly a 77% of the areas newly colonized for the period 2013–2022 (112% increases in relation to 2003–2012). Finally, we identified that the recovery plans defining the guidelines for the management of this population are outdated and its application only covers around 50% of the current presence range and 40% of the predicted range. More dynamic legal and management approaches are needed to avoid conservation success turning into failure, especially for charismatic species whose management is often subject to social conflicts.