First Population Assessment Report, Suitable Habitat and Ecological Corridors of the Endangered Kashmir Gray Langur Morphotype ( Semnopithecus ajax , Pocock 1928) in Khyber Pakhtunkhwa, Pakistan

The Himalayan Kashmir langur (Semnopithecus ajax) is an endangered colobine of the northwestern Himalayas, occurring in India and Pakistan; yet its ecology remains poorly studied. In Pakistan, it is known from Azad Jammu and Kashmir (AJK) and the northern districts of Khyber Pakhtunkhwa (KPK) but populations restricted to KPK has been neglected until the data. In this regard, we conducted 60 line-transect surveys (118.2 km) across 69.5 km² in three KPK districts-Mansehra, Kohistan, and Battagram-to estimate population density and abundance. Further, we modeled habitat suitability and connectivity modeling of langurs across its known range in Pakistan. The current study revealed mean density across the surveyed districts was 4.5 individuals/km² (95% CI: 2.3-6.7), with substantially higher densities in Mansehra (7.4; 95% CI: 3.3-11.5) compared to Kohistan-Battagram (KB) (1.3; 95% CI: 0.1-2.5). The total population in the study area was estimated at 314 individuals (95% CI: 143-485), with ~86% concentrated in Mansehra. Habitat suitability modeling (AUC = 0.96) identified four major suitable niche zones (SNZ) (~2,953 km²) across Pakistan, primarily montane forests between 1,300-3,100 m with > 40% canopy cover, though only ~82 km² (~1%) overlapped with existing protected areas. Connectivity analysis indicated forested corridors linking these niche zones, while fragmentation reduced connectivity in several regions. Our findings demonstrate that the langur persists in Pakistan as a small, fragmented, and forest-dependent population. Conservation of this threatened species will require improved forest protection, management of habitat corridors, and coordinated transboundary conservation efforts across its Himalayan range.