Decreasing brown bear (Ursus arctos) habitat due to climate change in Central Asia and the Asian Highlands

Abstract

Around the world, climate change has impacted many species. In this study, we used bioclimatic variables and biophysical layers of Central Asia and the Asian Highlands combined with presence data of brown bear (Ursus arctos) to understand their current distribution and predict their future distribution under the current rate of climate change. Our bioclimatic model showed that the current suitable habitat of brown bear encompasses 3,430,493 km2 in the study area, the majority of which (>65%) located in China. Our analyses demonstrated that suitable habitat will be reduced by 11% (378,861.30 km2) across Central Asia and the Asian Highlands by 2,050 due to climate change, predominantly (>90%) due to the changes in temperature and precipitation. The spatially averaged mean annual temperature of brown bear habitat is currently −1.2°C and predicted to increase to 1.6°C by 2,050. Mean annual precipitation in brown bear habitats is predicted to increase by 13% (from 406 to 459 mm) by 2,050. Such changes in two critical climatic variables may significantly affect the brown bear distribution, ethological repertoires, and physiological processes, which may increase their risk of extirpation in some areas. Approximately 32% (1,124,330 km2) of the total suitable habitat falls within protected areas, which was predicted to reduce to 1,103,912 km2 (1.8% loss) by 2,050. Future loss of suitable habitats inside the protected areas may force brown bears to move outside the protected areas thereby increasing their risk of mortality. Therefore, more protected areas should be established in the suitable brown bear habitats in future to sustain populations in this region. Furthermore, development of corridors is needed to connect habitats between protected areas of different countries in Central Asia. Such practices will facilitate climate migration and connectivity among populations and movement between and within countries.

Responses of an endangered brown bear population to climate change based on predictable food resource and shelter alterations

“…Above all, acorns and blueberries represent essential food items for Cantabrian brown bears and thus, oak forests and formations of clumped shrubs of blueberries are critical foraging habitats for this bear population (Naves et al, ; Rodríguez, Naves, Fernández‐Gil, Obeso, & Delibes, ). Few studies have focused directly on potential linkages between climate change and bear trophic plant resources (Butler, ; Roberts et al, ; Su et al, ), but some evidence exists that in the small and isolated brown bear population of Cantabrian Mountains (Rodríguez et al, ): (a) changes in bear diet and land use in relation to changing climate conditions have already occurred in the last 30 years; and (b) a trend towards increased local temperatures over the last few decades has been observed. Moreover, climate change impacts on vegetation have recently been reported in other areas of Northern Spain, where several plant species have shown noticeable changes in the phenology of leaf unfolding, flowering, fruiting and leaf fall (Peñuelas, Filella, & Comas, ).…”

Identifying climate refugia and its potential impact on Tibetan brown bear (Ursus arctos pruinosus) in Sanjiangyuan National Park, China

“…More recent implementation of conservation measures in national parks by the Chinese government has resulted in better protection for its wildlife and their habitats (Dai, Li, et al, ). Yet, climate change remains of great concern, as it may negate current conservation efforts, including those set to protect Tibetan brown bears (Balzotti et al, ; Stephens et al, ; Su et al, ). Assessing climatically suitable habitat is a key step in developing proactive strategies that reduce the impacts of climate change on the brown bear.…”

“…However, there were few suitable habitat areas in the western region of Yangtze River Zone. These results may be explained by differing key factors that affect species distribution at varying spatial scales, including temperature seasonality, precipitation seasonality, temperature constancy, and altitude (Su et al, ).…”

“…Loss of suitable brown bear habitat due to climate change has been observed in modeling studies from other Asian countries. For example, a large proportion of potential suitable habitat for brown bear was predicted to be lost in India, Pakistan, and Nepal by 2050, with loss in protected areas anticipated to be severe (Su et al, ). Possible outcomes which could result without adequate conservation action include brown bear population crashes due to insufficient habitat and movement into residential areas would cause conflicts between humans and brown bears (Dai, Xue, Cheng, et al, ).…”

“…Habitat quality and loss directly affect how wild animals exploit the resources available to them (Hiller, Belant, & Beringer, ). Loss of brown bear habitat causes shortages in natural food availability, which may increase dependence on food linked to anthropogenic sources, increasing levels of livestock depredation and human‐bear conflicts (Dai, Xue, Cheng, et al, ; Dai, Xue, Zhang, & Li, ; Su et al, ). Currently, suitable areas should be strictly protected to avoid loss of habitat and natural food sources with priority given to localities less susceptible to climate change.…”