We estimated leopard (Panthera pardus fusca) abundance and density in the Bhabhar physiographic region in Parsa Wildlife Reserve, Nepal. The camera trap grid, covering sampling area of 289？km2 with 88 locations, accumulated 1,342 trap nights in 64 days in the winter season of 2008-2009 and photographed 19 individual leopards. Using models incorporating heterogeneity, we estimated 28 (±SE 6.07) and 29.58 (±SE 10.44) leopards in Programs CAPTURE and MARK. Density estimates via 1/2 MMDM methods were 5.61 (±SE 1.30) and 5.93 (±SE 2.15) leopards per 100？km2 using abundance estimates from CAPTURE and MARK, respectively. Spatially explicit capture recapture (SECR) models resulted in lower density estimates, 3.78 (±SE 0.85) and 3.48 (±SE 0.83) leopards per 100？km2, in likelihood based program DENSITY and Bayesian based program SPACECAP, respectively. The 1/2 MMDM methods have been known to provide much higher density estimates than SECR modelling techniques. However, our SECR models resulted in high leopard density comparable to areas considered better habitat in Nepal indicating a potentially dense population compared to other sites. We provide the first density estimates for leopards in the Bhabhar and a baseline for long term population monitoring of leopards in Parsa Wildlife Reserve and across the Terai Arc. 1. Introduction The leopard (Panthera pardus fusca Meyer, 1794) is one of the most widely distributed felids across the forested landscapes of the Indian subcontinent [1, 2]. Being a habitat generalist , the leopard has a wider fundamental niche than its larger congener, the tiger (Panthera tigris tigris Linnaeus), in terms of the habitat and area it occupies , extending from alluvial floodplains, subtropical deciduous moist and dry habitat in lowlands and Siwaliks, temperate deciduous forest habitat in mid hills and high mountains, to dry alpine forest in the Himalayas . Leopards occur sympatrically with tigers in Nepal, India, and Bhutan [6–8]. The tiger, being an apex predator, appeals to the public and serves as a flagship species . Perceived as more tolerant of anthropogenic influences, the leopard on the other hand has received less attention from conservationists despite its important functional role within ecosystems, including its potential to cause trophic cascades , its impact on mesopredators [11, 12], and its competitive role within its guild [13, 14]. In the human dominated landscape of today’s Indian subcontinent, habitat destruction and fragmentation remain major threats to leopards  and leopard numbers are declining
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