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Ngoprasert D.,King Mongkuts University of Technology Thonburi | Reed D.H.,University of Louisville | Steinmetz R.,World Wide Fund for Nature Thailand Office | Gale G.A.,King Mongkuts University of Technology Thonburi

Assessing the conservation status of species of concern is greatly aided by unbiased estimates of population size. Population size is one of the primary parameters determining urgency of conservation action, and it provides baseline data against which to measure progress toward recovery. Asiatic black bears (Ursus thibetanus) and sun bears (Helarctos malayanus) are vulnerable to extinction, but no statistically rigorous population density estimates exist for wild bears of either species. We used a camera-based approach to estimate density of these sympatric bear species. First, we tested a technique to photograph bear chest marks using 3 camera traps mounted on trees facing each other in a triangular arrangement with bait in the center. Second, we developed criteria to identify individual sun bears and black bears based on chest-mark patterns and tested the level of congruence among 5 independent observers using a set of 234 photographs. Finally, we camera-trapped wild bears at 2 study areas (Khlong E-Tow, 33 km2, and Khlong Samor-Pun, 40 km2) in Khao Yai National Park, Thailand, and used chest marks to identify individual bears and thereby derive capture histories for bears of each species. Average congruence among observers' identifications of individual bears was 78.4% for black bear and 92.9% for sun bear across sites. At Khlong E-Tow, we recorded 13 black bears (8 M, 4 F, 1 unknown sex) and 8 sun bears (1 M, 5 F, 2 unknown sex). At Khlong Samor-Pun, we recorded 10 black bears (6 M, 4 F) and 6 sun bears (4 M, 2 F). We used a spatially explicit capture-recapture method, resulting in density estimates of 8.0 (SE = 3.04) and 5.8 (SE = 2.31) black bears per 100 km2 and 5.9 (SE = 3.07) and 4.3 (SE = 2.32) sun bears per 100 km 2 for each study area, respectively. Our camera trap design and chest-mark identification criteria can be used to estimate density of sun bears and black bears, enhancing knowledge of the conservation status of these threatened and little-known bear species. © 2012 International Association for Bear Research and Management. Source

Ngoprasert D.,King Mongkuts University of Technology Thonburi | Steinmetz R.,World Wide Fund for Nature Thailand Office | Reed D.H.,University of Louisville | Savini T.,King Mongkuts University of Technology Thonburi | Gale G.A.,King Mongkuts University of Technology Thonburi
Journal of Wildlife Management

Wild bear populations in Southeast Asia are threatened with extinction, but the ecology and distribution of the 2 species occurring in the region's protected areas is poorly known, so there is little scientific basis underlying conservation strategies. We used bear signs, primarily claw marks on climbed trees, to study habitat selection and distribution of Asiatic black bear (Ursus thibetanus) and sun bear (Helarctos malayanus) across Khao Yai National Park, Thailand from March to December 2008. We found black bear claw marks in 24 of 30 random sample blocks (80%), indicating that this species was widely distributed across Khao Yai. Sun bear signs were much scarcer: their claw marks occurred in 11 blocks (37%); data were too sparse for sun bear so we limited our focus to Asiatic black bear. Using logistic regression, we found that fruit abundance best explained variation in presence of black bear, whereas human disturbance, distance to park edge, elevation, and ground cover had little influence. Fruits appear to be a key resource for Asiatic black bears, and factors affecting fruit abundance or shifts in seasonality (e.g., climate change) will impact bear populations. Knowledge of this relationship will allow managers to be more proactive in managing bears. We recommend using sign surveys for monitoring changes in black bear occupancy as they are inexpensive, efficient, and can be conducted by trained park rangers. © 2011 The Wildlife Society. Source

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