Projected shifts in the distribution range of Asiatic black bear (Ursus thibetanus) in the Hindu Kush Himalaya due to climate change

Abstract

<p>Climate change is one of the main threats to many vulnerable species, including the Asiatic black bear (Ursus thibetnus), due to disruption in biological and ethological responses, hibernation, reproduction, and intraspecific and interspecific interactions. To assess the current and future distribution of the Asiatic black bear in the Hindu Kush Himalaya (HKH), we used maximum entropy modeling (MaxEnt) with species presence data and bioclimatic (under two representative concentration pathways i.e., RCP4.5 and RCP8.5) and non-climatic variables. We identified current and future suitable habitats, climate refugia, increased suitable habitat and vulnerable habitat. Our model estimated that a 487,036 km² area of the HKH is currently suitable for the Asiatic black bear, and projected that 458,060 km² and 470,368 km² areas will be suitable under RCP4.5 and RCP8.5, respectively, by 2050. The maximum area (of the current suitable habitat) projected as climate refugia under RCP4.5 and RCP8.5 was 350,510 km² and 342,796 km² , respectively. The model projected a shift in the bear’s range towards higher elevations, primarily >3500 m under both RCPs with change an average elevation from 2697 m (under current scenario), to 2949 m (under RCP4.5) and 3021 m (under RCP8.5). Such changes may lead to scarcity of natural resources and increase the dependency of bears on human-related food, which will likely result in increased human-bear conflicts and bear mortalities. The recommended implications, including climate refugia management by habitat corridors, establishment of and increased status for existing natural reserves, improved adaptive management capacity, and strengthening monitoring of bear populations could help to mitigate the intensity of the adverse impacts of climate change on the bear’s population.</p>