Thapa, K., Jackson, R., Gurung, L, Acharya, H. B., Gurung, R. K.,. (2021). Applying the double observer methodology for assessing blue sheep population size in Nar Phu valley, Annapurna Conservation Area, Nepal. Wildlife Biology, , 1–11.
Abstract: This study was undertaken in spring, 2019 to assess the applicability of the double-observer survey method for estimating blue sheep Pseudois nayaur abundance in Nar-Phu valley of Manang District located in Annapurna Conservation Area of northern Nepal. Since counting large mammals in rugged mountain habitat poses a special challenge, we tested the efficacy of the double observer method for generating robust population estimates for this important protected area. The overall detection probability for observers (O1 and O2) was 0.94 and 0.91 for a total of 106 groups comprised of 2059 individual blue sheep. We estimated the area’s blue sheep population at 2070 (SE ± 168.77; 95% CI 2059–2405) for the 246.2 km2 of sampled habitat. We determined blue sheep to be widely distributed within the study area with a mean density of 8.4 individuals per km2 based on a total study area of 246.2 km2. We discuss demographic population structure and identify limitations when applying the double observer approach, along with recommending viewshed mapping for ensuring more robust density estimates of mountain-dwelling ungulates like blue sheep or ibex that inhabit extremely heterogeneous terrain which strongly influences sighting distances and overall animal detection rates.
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Wegge, P., Shrestha, R., Flagstad, O. (2012). Snow leopard Panthera uncia predation on livestock and wild prey in a mountain valley in northern Nepal: implications for conservation management. Wildlife Biology, 18(10.2981/11-049), 131–141.
Abstract: The globally endangered snow leopard Panthera uncia is sparsely distributed throughout the rugged mountains in Asia.
Its habit of preying on livestock poses a main challenge to management. In the remote Phu valley in northern Nepal, we
obtained reliable information on livestock losses and estimated predator abundance and diet composition from DNA
analysis and prey remains in scats. The annual diet consisted of 42%livestock. Among the wild prey, bharal (blue sheep/
naur) Pseudois nayaur was by far the most common species (92%). Two independent abundance estimates suggested that
there were six snow leopards in the valley during the course of our study. On average, each snow leopard killed about one
livestock individual and two bharal permonth. Predation loss of livestock estimated fromprey remains in scats was 3.9%,
which was in concordance with village records (4.0%). From a total count of bharal, the only large natural prey in the area
and occurring at a density of 8.4 animals/km2 or about half the density of livestock, snow leopards were estimated to
harvest 15.1% of the population annually. This predation rate approaches the natural, inherent recruitment rate of this
species; in Phu the proportion of kids was estimated at 18.4%. High livestock losses have created a hostile attitude against
the snow leopard and mitigation measures are needed. Among innovative management schemes now being implemented
throughout the species’ range, compensation and insurance programmes coupled with other incentive measures are
encouraged, rather than measures to reduce the snow leopard’s access to livestock. In areas like the Phu valley, where the
natural prey base consists mainly of one ungulate species that is already heavily preyed upon, the latter approach, if
implemented, will lead to increased predation on this prey, which over time may suppress numbers of both prey and
predator.
Keywords: bharal, blue sheep, diet, genetic sampling, naur, Panthera uncia, predation, Pseudois nayaur, scat analysis, snow leopard, wildlife conflict
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