Projected climate change threatens Himalayan brown bear habitat more than human land use. (1st February 2021)

• Record Type: Journal Article
• Authors: Dar, S. A.; Singh, S. K.; Wan, H. Y.; Kumar, V.; Cushman, S. A.; Sathyakumar, S.
• Is Part Of: Animal conservation. Volume 24:Number 4(2021)
• Page Start: 659
• Page End: 676
• Publication Date: 2021-02-01
• Subjects: adaptation -- extinction -- habitat loss -- Himalaya -- large carnivore -- range shift -- scaling -- Ursus arctos isabellinus; Conservation biology -- Periodicals; Wildlife conservation -- Periodicals; Conservation de la biodiversité; Conservation de la faune; Périodique électronique (Descripteur de forme); Ressource Internet (Descripteur de forme); 333.95416
• DOI: 10.1111/acv.12671
• Languages: English
• ISSNs: 1367-9430

Abstract

Abstract: Climate change and land use change jointly are the largest drivers of population declines, range contraction and extinction for many species across the globe. Wide‐ranging and large‐bodied species are especially vulnerable to habitat loss and fragmentation due to their typically low population densities, reflecting their need for extensive and connected habitats. We used the multi‐scale Random Forests machine learning algorithm to identify factors driving the habitat selection and future changes in habitat of Himalayan brown bear, an iconic wide‐ranging and large‐bodied species of high conservation interest, across a range of spatial scales. Habitat selection of brown bears was scale‐dependent, with most variables selected at broad scales. Climatic variables such as maximum temperature of coldest month, minimum temperature of warmest month and the potential evapotranspiration of wettest quarter strongly influenced habitat selection of brown bears. Future projections indicate a strong difference between the high and low emission scenarios. Alarmingly, our model suggests that high emission scenarios, with or without land use change, may result in a decline of brown bear habitat of >90% by the end of the century. In contrast, low emission scenarios are projected to reduce brown bear habitat by <23%, with much of the species range shifting to higher elevations. This study provides an integrative understanding of scale‐dependent variables in brown bear habitat selection, providing critical information for prioritizing areas for habitat management and conservation. Most importantly, our future projections imply that traditional conservation efforts, such as in situ conservation, will not be sufficient to protect the species without climate change mitigation. The incorporation of climate change mitigation and adaptation in conservation strategies will be one of the most pressing priorities in biodiversity conservation in this region. Abstract : By comparing multi‐scale habitat selection of Himalayan brown bears across current and future climate change and land use change scenarios, it is revealed that emission levels play a significant role in deciding the severity of habitat loss. Under low emission scenarios, a few habitat remnants will remain with some shifting to higher elevation areas. Under high emission scenarios, however, nearly all habitat (>90%) will be lost by the end of the century, with or without human land use change. Also, habitat selection of Himalayan brown bear is scale‐dependent with most variables selected at broad scales and a few variables selected at fine scales. Climatic variables such as maximum temperature of coldest month, minimum temperature of warmest month, and potential evapotranspiration of wettest quarter were the most important variables. Our model projections imply the importance of combating climate change to prevent an otherwise ominous fate of the Himalayan brown bears.