Understanding patterns of distribution and space-use by Ursus thibetanus in Khangchendzonga, India: Initiative towards conservation

Abstract

Increasing rate of bear-human conflict and declining black bear population remains a conservation paradox throughout its distributional range. Sound information on the patterns and dynamics of bear occurrence seems prerequisite towards addressing this issue, particularly in sub-tropical and temperate ecosystems. We aimed to understand the patterns of space-use and distribution of Asiatic black bears Ursus thibetanus in the Khangchendzonga Biosphere Reserve (BR) of Eastern Himalaya, and the factors influencing the same. We also modelled the distribution and extent of suitable habitats for bears in the Khangchendzonga landscape. We used sign surveys, trail monitorings, camera trapping, occupancy based space-use modelling and presence-only habitat suitability modelling using Ecological Niche Factor Analysis (ENFA). Almost all the black bear evidences (98%) were recorded from temperate and subalpine habitats. Broadleaved and coniferous forests were the best predictors for bear occurrence, and the percentage of acorn producing trees in temperate zone was the most important factor positively influencing the proportion of site utilization by bears during pre-hibernation periods. ENFA results indicate black bear as a ‘habitat specialist species’ and delineated only a small portion of the Biosphere Reserve (5.35%) as highly suitable for its occurrence. These highly suitable patches mostly occurred in the buffer zone outside the National Park boundary and were therefore, found as more susceptible to conflicts. Such patterns in habitat preference highlight the importance of local landscapes and demand for site specific conservation and management strategies for black bears in Khangchendzonga.