Blue sheep in the Annapurna Conservation Area, Nepal: habitat use, population biomass and their contribution to the carrying capacity of snow leopards

Abstract

The Himalaya region of Nepal provides a habitat for the endangered snow leopard (Panthera uncia) and its principal prey species, the blue sheep (Pseudois nayaur). The aim of this study was to describe the habitat, the distribution and the population structure of blue sheep, and to estimate their contribution to the carrying capacity of snow leopard in the upper Mustang region of Nepal. Blue sheep were recorded at altitudes from 3209-5498 m on slopes with gradients of 16-60° and aspects of 40°NE to 140°SE. A total of 939 blue sheep were counted in the upper Mustang region, and 98 were counted in the Yak Kharka region of Manang district; however, upper Mustang had the lowest population density of blue sheep recorded within their distribution range in Nepal (0.86 blue sheep/km(2)). The results of the study show that a higher density of blue sheep is associated with greater plant species diversity. The most important species present in the blue sheep habitat were Kobresia pygmaea, Artemesia spp., Lonicera spp., Lancea tibetica, Poa spp., Astragalus spp. and Ephedra gerardiana. It is estimated that the existing blue sheep population biomass of approximately 38 925 kg in the upper Mustang region could support approximately 19 snow leopards (1.6 snow leopards/100 km(2)).

Abundance of snow leopard (Panthera uncia) and its wild prey in Chhekampar VDC, Manaslu Conservation Area, Nepal

“…Because of the habitat destruction and other anthropogenic activities, snow leopards are at high risk (Wegge et al, 2012;Devkota et al, 2013), so knowing how these factors influence habitat use is critical to the conservation of snow leopard (Wolf and Ale, 2009). The density of blue sheep (3.8 animals/km 2 ) in the study area as compared to other regions of Nepal, is higher than in the SPNP (2.27 animal/km 2 ; Devkota et al, 2013) and upper region of Mustang district (0.86 animal/km 2 ; Aryal et al, 2014). However, the density of the blue sheep in this study area is quite less than that of 8.4 animals/km 2 in the Phu Valley of Manang district (Wegge et al, 2012).…”

Abundance and threats to the survival of the snow leopard – a review

“…ESSR -ecological sustainable stocking rate; PBY -prey biomass /snow leopard/year (~548kg/year, 1.5kg/day -Schaller 1977); PD -total prey biomass/km 2 ; SUF -safe use factor -the total biomass production of the ecological site that is available for use by animals with the remaining biomass available for ecological sustainability (Alberta Sustainable Resource Development 2004; Aryal 2007;Aryal et al 2014); in Nepal, Aryal et al (2014) used 25% for SUF due to the presence of other predators (lynx, red fox, jackal, wolf); it means that snow leopards can consume just 25% of the total sheep population and the rest is available to other predators; BD -birth : death, for instance for blue sheep in Nepal it is presumed to be 2:1, based on the estimate that 50% of blue sheep die between birth and 2 years of age in the Dhorpatan Hunting Reserve (Schaller 1977;Wegge 1979); EHD -environment and human disturbance factors in the habitat (poaching, livestock grazing) where the grassland is that sustains the prey : predator population; e.g., the Upper Mustang in Nepal has a lower young-toold male ratio than Lower Mustang due to its lower productivity (Ale et al 2014); productive grasslands are expected to have a higher proportion of young males while the opposite would be the case for ungulate populations occupying degraded grasslands (Ale et al 2014).…”

“…As mentioned above, herders of small and medium-sized livestock are notably vulnerable to losses of livestock, which can be reduced corralling the livestock at night. Understanding what determines the carrying capacity (based on the distribution and population structure) of predators such as snow leopard will simplify the management of the human-wildlife conflict (Aryal et al 2014). One of the major issues is the protection of prey populations (e.g.…”

“…One snow leopard needs about 20 to 30 adult blue sheep annually . For instance, the habitat of blue sheep is spaced out in mountainous terrain from the Qilian Mountains in the north to the Himalayas in the south (Aryal et al 2014), which includes Nepal, India, China, Pakistan and Mongolia. Unfortunately, there are no accurate estimates of blue sheep abundance (Schaller 1977;Oli et al 1993).…”

“…Domestic livestock is a potential prey of snow leopard, e.g., in many cases snow leopard opportunistically kills more domestic livestock than wild prey. Our knowledge of its diet range and especially of the relative importance of individual species in its diet is still anecdotal and therefore, it would be appropriate to conduct additional surveys to better understand the trophic interactions in leopard-prey systems (Aryal et al 2014). …”