3.4 Snow leopard-prey availability
An annual food requirement for one snow leopard is 1343 kg. Standing
available food biomass of both wild and domestic livestock was
calculated at 355, 236 kg. Naur, the snow leopard’s staple food in the
KCA, was calculated at 47, 736 kg and domestic yak, 307, 500 kg.
Harvesting rate of the estimated 24 snow leopards was about 7% per
annum. If a snow leopard killed 21 Naur annually then the extant 24 snow
leopards would require 504 Naur per annum. Without the biomass
contribution of small mammals and livestock, the estimated available
Naur biomass of 47, 736 kg gives a predator- prey ratio of 1:59 in KCA
on a weight basis. Here in the KCA the proportion of young (Naur) is
estimated at 17%, but predation rate is almost double at 28%.
DISCUSSION
The study estimated snow leopard density at 3.9/ 100
km2 (95% CI= 3.1- 4.8; SD: 0.8) in the KCA. This
estimate is lower than the densities recorded in the Phu valley by
Wegge, et al., 2012 (6 individuals/125 km2), by
Janecka et al., 2011 in Mongolia (5.9 individuals/100
km2; 95% CI= 3.4- 8.0) and Oli, 1994 in Manang
4.8-6.7/100 km2. Jackson & Ahlborn (1989) estimated
5-10 snow leopards/100 km2 in the prime habitat of the
Langu valley and then extrapolated this estimate to a country-wide
density of less than 0.1- 0.5 snow leopards/100 km2 in
most parts of Nepal. The studies such as Jackson and Ahlborn (1989) and
Oli (1997) which were based on expert opinion, sign evidence, VHF radio
telemetry, and their extrapolations may be less reliable (McCarthy &
Chapron, 2003). Chetri et al. (2019) however, estimated a lower density
of 1.07 individuals/100 km2 (95% CI: 0.71- 1.62) in
Annapurna and 1.16 individuals/100 km2 (95% CI: 0.73-
1.87) in Manaslu of Nepal by modeling genetic sampling over a larger
area. This lower density was likely due to Chetri et al. (2019)
including the high mountain zone up-to 6000 m as potential snow leopard
habitat in their study rather than the 3000-5400 m range considered
(prime and fair) suitable snow leopard habitat in Nepal (Jackson &
Hunter, 1996). Recently, Khanal et al., 2020 estimated lower densities
using remote camera traps compared to our estimates i.e., 2.51/100
km2 (95% CI: 1.36= 4.60) in Upper Dolpa and 1.21/100
km2 (95% CI: 0.58-2.54) in Lower Dolpa of SPNP west
Nepal. The estimated lower snow leopard density in western Nepal
compared to the KCA could be a result of camera trap analysis from this
study excluding sub-adult and young in density estimates.
Based on food requirements, 24 snow leopards would need an annual
biomass of 32,232 kg in the KCA. Snow leopard diet in this study
comprised both wild (49%) and domestic (45%) prey. Our estimates were
consistent with that of Bagchi & Mishra (2006) and Wegge et al. (2012),
with 58% and 42% livestock in India and Nepal respectively. Chetri et
al., 2017 estimated 57% of Naur and 31% livestock in snow leopard diet
within the Annapurna-Manaslu region, similar to the estimates of Lovari
et al. (2013) and Ferretti et al. (2014) in the Mt Everest region (25%
livestock and 56% Himalayan tahr). Within the Dolpa region of western
Nepal however, Devkota et al., 2013 found that snow leopard diet
consisted of only 30% Naur where marmot (buffer prey) and small
livestock are plentiful. Oli (1994) stressed that snow leopards killed
livestock because they are abundant and easy to kill compared to wild
prey, not because they were a preferred food source. These findings are
consistent with the results of our study in the KCA, particularly with
the standing biomass of yak representing approximately 2/3 of the total
volume (with Naur occupying the other 1/3).
Based on the estimate of Jackson & Ahlborn (1989), that an adult snow
leopard requires 20-30 Naur annually to survive, 24 snow leopards would
need to consume 480-720 Naur per year. Jackson and Ahlborn (1989)
hypothesized that a single snow leopard requires an estimated population
of 150- 230 Naur to achieve this (possibly less in areas where other
prey species are easily available). In the KCA snow leopards were
estimated to harvest 28% of the Naur population annually, nearly twice
the amount estimated (15.1%) by Wegge et al. (2012) in the Phu valley,
however the proportion of young Naur was found to be similar between the
KCA and Phu (17% compared to 18.4%; Wegge et al., 2012). This
difference could be explained by the greater availability of small
livestock in the Phu Valley (Wegge et al., 2012; Thapa, 2005) compared
to the KCA, providing snow leopards with a smaller prey target. The
higher proportion of prey to predators around Manang (159:1; Oli, 1994)
compared to KCA (59:1) could also explain this difference in Naur
consumption. As well as the KCA having less “easy” small livestock
prey available compared to Dolpa, Manang and the Phu Valley (Devkota et
al., 2013; Wegge et al., 2012; Oli, 1994), snow leopards in the area
also share habitat with two other apex predators, the common leopard
along the forested- edge habitat in the south (Thapa et al., 2013) and
grey wolf (Subba et al., 2017) in the north which will add significantly
to the competitive pressures on Naur populations. Further long-term
studies examining snow leopard, common leopard and wolf interactions are
therefore needed.
The current situation indicates that available wild prey biomass is
insufficient to support the estimated snow leopard population in the
KCA. Therefore, livestock play an important role for the survival of
snow leopard here in Nepal and elsewhere (Khanal et al., 2020; Mishra et
al., 2016; Johansson et al., 2015; Sharma et al., 2015; Wegge et al.,
2012; Shehzad et al., 2012; Oli et al., 1993). In most of the snow
leopard’s range, current community conservation initiatives focus on
compensation and incentive, rather than preventative measures. Recently
introduced Community- Managed Livestock Insurance Schemes in the KCA are
offering huge promise for the long-term survival of snow leopards in the
area by reducing the incentive for retribution killings (Gurung et al.,
2011). However, financial compensation for livestock losses alone will
not solve the problem (Thapa, 2006; Jackson, 2015). Along with this
scheme improvement, there needs to be a focus on preventive measures
such as improved livestock guarding as well as engaging and educating
local people to be citizen scientists on the importance of snow leopard
conservation, involving them in long-term monitoring programs and
promotion of ecotourism.
ACKNOWLEDGEMENTS Permission was granted to conduct the study by
the Department of National Parks and Wildlife Conservation (Ref.:
689/069/070). We are grateful to WWF International for awarding us the
PRINCE BERNHARD scholarship (Grant no. 9Z0533.01) and WWF Nepal for the
research grant to undertake this study. We also want to thank the Nepal
Engineering College (nec-cps) especially the Director Prof. Dr. Khem Raj
Sharma, Associate Prof. Dr. Narayan Kumar Shrestha, Associate Prof.
Jhamak Bahadur Karki and Asst. Prof. Mr. Robert Dongol including Prof.
Mukesh Kumar Chalishe (TU) for their guidance and critical review during
drafting the paper.
Our sincere thanks go to members of the Snow Leopard Conservation
Committees of KCA who collected the scat samples and also assisted us in
gathering the Naur and domestic stock data in the field. We also
acknowledge the Kangchenjunga Conservation Area Management Council and
Kangchenjunga Conservation Area Project for mobilizing the Citizen
Scientists who helped us gather reliable data from field. The team at
the Center for Molecular Dynamics Nepal (CMDN) generously processed and
analyzed our fecal samples in the lab. Finally, we are grateful to Mr.
Gokarna Jung Thapa (GIS expert, WWF Nepal) for assisting us in preparing
the map.