AbstractEffective management of charismatic large carnivores requires robust monitoring of their population at local, regional and global scales. While enormous progress has been made to estimate carnivore populations at local scales, estimates at regional and global scales remain elusive. In the first systematic effort at a large regional scale, we estimated the population of the elusive snow leopardPanthera unciaover an area of 26,112 km2in the Indian state of Himachal Pradesh.We stratified the entire snow leopard habitat in Himachal Pradesh based on an occupancy survey. Subsequently, we conducted camera trapping surveys at 10 sites distributed proportionately, that is with similar coverage probability across the three strata. We conducted simulations to understand how unidentified captures could affect our model estimate. We also assessed populations of the primary wild ungulate prey of snow leopards – blue sheepPseudois nayaurand Siberian ibexCapra sibirica.Our results yielded a mean estimated density of 0.19 (95% confidence interval [CI]: 0.12–0.31) snow leopards per 100 km2and population size of 51 (95% CI: 34–73) snow leopards in Himachal Pradesh. The density estimates for individual sites ranged from 0.08 to 0.37 snow leopards per 100 km2. Simulations showed that unidentified snow leopard captures did not seem to affect the accuracy of our model estimate but could have affected the precision. Wild ungulate prey density ranged from 0.11 to 1.09 per km2. Snow leopard density showed a positive linear relationship with prey density (slope = 0.25,SE = 0.08,P = 0.01,R2 = 0.51).Our study shows the earlier opinion‐based estimate for Himachal Pradesh to have been significantly positively biased. Using occupancy surveys to stratify large areas in order to design camera trap surveys addresses one of the common spatial sampling biases, that is limited sampling of only prime snow leopard habitats. Our work validates two‐step approach recommended in the ongoing initiative of the 12 snow leopard range countries for Population Assessment of World's Snow leopards (PAWS program), and cautions against the use of opinion‐based estimates for assessing the status of species of critical conservation importance.

Abstract The Nilgiri tahr Nilgiritragus hylocrius is an Endangered species of mountain ungulate endemic to the Western Ghats of India, a biodiversity hotspot. Habitat fragmentation, hunting and a restricted range are the major threats to this species. Although several surveys have assessed the species’ status, a population estimate based on a scientifically robust method is needed. We used the double-observer method to estimate the population of the Nilgiri tahr in the Anamalai Tiger Reserve, a protected area in the Western Ghats. We walked 257 km of transects across the Reserve, covering 36 grassland blocks (i.e. clusters of montane grasslands that were relatively separate from each other). We counted a minimum of 422 individuals in 28 groups, and estimated the tahr population in the study area to be 510 individuals (95% CI 300–858) in 35 groups. The male:female ratio was 0.71 and the young:female ratio was 0.56. Comparing our estimate with previous surveys suggests that the Nilgiri tahr population in Anamalai Tiger Reserve is stable. We found the double-observer survey method to be appropriate for population estimation and long-term monitoring of this species, and make recommendations for improved field protocols to facilitate the implementation of the method in the tropical mountains of the Western Ghats. Our findings suggest that the Reserve harbours 20–25% of the global population of the Nilgiri tahr, highlighting the area's importance for the conservation of this species.

Ungulate conservation directly affects conservation of their predators and habitats. Assessing conservation status of ungulates found in the mountains is particularly challenging given the tough terrain and extreme weather. This is true for Central and South Asia’s mountains which harbour high ungulate diversity. Urial Ovis vignei, a Vulnerable wild sheep, occurs patchily across Asian mountains. Ladakh urial Ovis vignei vignei is a subspecies restricted to Ladakh and Gilgit-Baltistan in the trans-Himalaya. Poor understanding of its conservation status has limited conservation efforts in the region. We conducted a distribution survey using single-season single-species occupancy, with spatial replicates accounting for auto-correlated replicate-level presence across the entire potential urial habitat (3425km2) in Ladakh, India. We then identified remaining populations and conducted double-observer surveys to estimate densities. We found urial to use only 32% (16–53%) of its presumed range. We estimated densities of 1.27 (1.27–1.39) urial km−2 and 0.96 (0.96–1.10) urial km−2 across the two landscapes covering 18% of surveyed area. These two areas are currently the last remaining strongholds for the species in India, yet densities were lower than expected when compared to previous studies. Urial distribution in India overlaps with human use like habitations, livestock grazing, and roads, hence effective conservation of the species will need involvement of local communities. We propose annual monitoring of urial and setting up community-based livestock-free reserves across the two landscapes. More such robust investigations at meaningful large scales are needed to direct conservation action for the understudied mountain ungulates of high Asia.

Endemic to the Indian sub-continent, the population of the Blackbuck (Antilope cervicapra) was estimated at 43,500 in India in 1989. Today, due to large-scale land use and land-cover change, poaching, and loss of habitat due to invasive species, their habitat has mostly been restricted to a few isolated patches of open grassland and agricultural fields. Living in close proximity to human settlements, these ungulates are worshipped in some places and have actually thrived in some protected areas. The alien invasive, Prosopis juliflora, which was introduced and now is widespread in semi-arid areas, has been known to drive substantial losses of native vegetation in savannas and grasslands, thereby resulting in the possible shrinking of blackbuck habitat. Confoundingly, blackbuck are also known to eat Prosopis juliflora seeds, and inadvertently aid in its dispersion through their dung piles in high density lekking aggregations. This study seeks to explain the land-cover and land-use factors that influence the blackbuck occupancy in the Moyar valley in Tamil Nadu (with a special focus on the invasive Prosopis juliflora). This was done by combining detection probability data that accounts for imperfect detection of blackbuck occurrence with covariates hypothesized to influence site occupancy of blackbuck in the Moyar Valley. The Moyar Valley encompasses portions of the Sathyamangalam Tiger Reserve, Nilgiri North and Coimbatore forest divisions in the Western Ghats. This valley holds a large contiguous population estimated in the past to be 800-1000 individuals, although this estimate needs to be verified using rigorous line transect data that accounts for detection probability. Little is also known about factors influencing habitat for blackbuck in this landscape. This study generates baseline data and identifies factors affecting blackbuck distribution in the Moyar Valley.