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

Junhu Su,Hongyan Fu,Zhigang Dou,Liji Wu,Xilite Dabu,Sambandam Sathyakumar,Achyut Aryal,Sean C P Coogan,Uttam Babu Shrestha,Yila Suo,Weihong Ji,Munkhnast Dalannast,Ibrahim M Hegab

doi:10.1002/ece3.4645

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.

Highlights

Around the world, climate change has had significant direct and indirect impacts on terrestrial species, by being a major cause of speciation and species extirpation (Pound & Salzmann, 2017)
Our results showed that the current suitable habitat will be reduced by 11% (378,861 km2) across Central Asia by 2,050 (Table 3) due to climate change
Across Central Asia, suitable habitats of the brown bear are widely distributed in higher elevation regions and are predicted to moderately decrease by 2,050 due to climate change; the extent of the change is not felt in the countries

Summary

| INTRODUCTION

Climate change has had significant direct and indirect impacts on terrestrial species, by being a major cause of speciation and species extirpation (Pound & Salzmann, 2017). Brown bear (Ursus arctos) is a solitary, non‐territorial species with a promiscuous or polygamous mating system (Jerina, Jonozovic, Krofel, & Skrbinsek, 2013; Figure 1) It has a circumglobal distribution in the northern hemisphere, occurring in North America (The United States and Canada), Europe, and northern and Central Asia (McLellan et al, 2008). In Central Asia and the Asian Highlands, brown bear distribution is mostly limited to higher elevation areas where more pronounced effects of climate change have been reported (Aryal, 2012; Aryal et al, 2014) In these regions, brown bear distribution and presence may be impacted by changing thermal regimes, vegetation, and prey abundance.

| MATERIAL AND METHODS

Findings

| DISCUSSION