Application of Capture and Recapture Method for Estimating the Population Size of Men Who Have Sex with Men in Chiang Mai, Thailand

Background: Men who have sex with men (MSM) are highly vulnerable to HIV infection, but this population can be particularly difficult to reach in Thailand. This study aimed to estimate the number of MSM in Chiang Mai Thailand, in order to plan HIV control and prevention. Methods: The total of 348 potential MSM were identified at eight contact locations, including two public parks, two bars, two massage parlors and two pubs in Chiang Mai. Trained 16 research enumerators and 16 enumerators were trained to extend a recruitment of brooches to MSM. The MSMs were captured one week apart. A record was kept of when, where and by whom the invitation was extended and received, and of refusals. The total estimate of MSM was derived from capture-recapture calculation. Results: The total MSM in Chiang Mai Thailand estimated by capture and recapture method was 733 (95%CI = 480 - 948) or the estimate was 7.3% (95%CI = 7.1% - 14.1%). Conclusions: Capture and recapture method can be used to enumerate and provide accurate and reliable estimates of the MSM population in any area, provided that certain conditions are controlled. MSM who are engaged in personal community represent a sizeable population who urgently need to be targeted by HIV and STDs prevention strategies.

Spatial density estimate of the snow leopard, Panthera uncia, in the Central Tibetan Plateau, China

Knowledge of large carnivore population abundance is essential for wildlife management and conservation,but these data are often difficult to obtain in inherently low-density species.In particular,the snow leopard,Panthera uncia,an enigmatic cat occupying remote mountains in Central Asia,has received insufficient assessments of its population abundance because of logistical and methodological challenges.Here,we aimed to develop a robust density estimation of snow leopards based on 81 days of camera trapping within a contiguous and previously un-surveyed 1950 km2 area of habitat on the Tibetan Plateau(Mayue Township,Shenzha County,Tibet Autonomous Region,China).By applying spatially explicit capture–recapture models,we produced an estimate of 1.40(95%CI:1.06–1.84)individuals per 100 km2.Results also suggested sex-specific variation in the range of movement around activity centers,with male(N=10,σ=4.02)movement considerably greater than female(N=8,σ=1.84)move-ment.Thefindings can serve as a reliable baseline reference for assessing the population trends of this endangered felid species with future estimates.This study will provide context to contribute toward a better understanding of ecological factors shaping the distribution and abundance of snow leopards and the related conservation measures needed to sustain their long-term survival on the Tibetan Plateau.

Estimating the population density of the Asian tapir (Tapirus indicus) in a selectively logged forest in Peninsular Malaysia

The endangered Asian tapir(Tapirus indicus)is threatened by large-scale habitat loss,forest fragmentation and increased hunting pressure.Conservation planning for this species,however,is hampered by a severe paucity of information on its ecology and population status.We present the first Asian tapir population density estimate from a camera trapping study targeting tigers in a selectively logged forest within Peninsular Malaysia using a spatially explicit capture-recapture maximum likelihood based framework.With a trap effort of 2496 nights,17 individuals were identified corresponding to a density(standard error)estimate of 9.49(2.55)adult ta-pirs/100 km2.Although our results include several caveats,we believe that our density estimate still serves as an important baseline to facilitate the monitoring of tapir population trends in Peninsular Malaysia.Our study also highlights the potential of extracting vital ecological and population information for other cryptic individual-ly identifiable animals from tiger-centric studies,especially with the use of a spatially explicit capture-recapture maximum likelihood based framework.

Density and carrying capacity in the forgotten tigerland:Tigers in the understudied Nepalese Churia

While there are numerous wildlife ecology studies in lowland areas of Nepal,there are no in-depth studies of the hilly Churia habitat even though it comprises 7642 km2 of potential wildlife habitat across the Terai Arc.We investigated tiger,leopard and prey densities across this understudied habitat.Our camera trapping survey covered 536 km2 of Churia and surrounding areas within Chitwan National Park(CNP).We used 161 trapping locations and accumulated 2097 trap-nights in a 60-day survey period during the winter season of 2010-2011.In addition,we walked 136 km over 81 different line transects using distance sampling to estimate prey density.We photographed 31 individual tigers,28 individual leopards and 25 other mammalian species.Spatial capture-recapture methods resulted in lower density estimates for tigers,ranging from 2.3 to 2.9 tigers per 100 km2,than for leopards,which ranged from 3.3 to 5.1 leopards per 100 km2.In addition,leopard densities were higher in the core of the Churia compared to surrounding areas.We estimated 62.7 prey animals per 100 km2 with forest ungulate prey(sambar,chital,barking deer and wild pig),accounting for 47%of the total.Based on prey availability,Churia habitat within CNP could potentially support 5.86 tigers per 100 km2 but our density estimates were lower,perhaps indicating that the tiger population is below carrying capacity.Our results demonstrate that Churia habitat should not be ignored in conservation initiatives,but rather management efforts should focus on reducing human disturbance to support higher predator numbers.