Snow leopards in Nepal 425
TABLE 3 Model-averaged parameter estimates and 95% confidence interval describing snow leopard occurrence in Api Nampa Conservation Area (Fig. 1) during October–November 2014.
Parameter1 Elevation
HumanDist Prey
Estimate2 0.12
−0.09 0.02
Adj. SE 0.02
0.02 0.02
Confidence interval 0.08–0.15
−0.05–−0.13 −0.02–0.06
z
4.69 3.49 1.15
P
0.00 0.04 0.24
1Elevation (m); HumanDist, presence/absence of recent human use of the area; Prey, number of bharal encountered. 2Averaged from all models.
2006; Sargarmatha National Park: 4.2 signs/km, Ale et al., 2007; Annapurna Conservation Area: 5.8 signs/km, Ale et al., 2014; Manaslu Conservation Area: 3.5 signs/km, Devkota et al., 2017), the prey biomass was sufficiently large to support a breeding population of snow leopards. Survey times may influence sign encounter rate. There may be a higher detection rate in winter and post-winter be- cause of accumulation of snow and minimal human pres- ence (Jackson & Hunter, 1996). Devkota et al. (2017), for example, surveyed both pre-winter (November– December) and post-winter (May–April). Our surveys, however, were conducted just after the migratory livestock grazing and fungal caterpillar collection season (October– November). In addition, we did not consider putative snow leopard scats in our analysis, which could have low- ered the overall sign encounter rate.
Factors influencing sign encounter rate
Contrary to our initial expectation, there was only a weak positive association between the availability of bharal and the number of snow leopard signs. Although abundance of wild prey is a key determinant of habitat use and abun- dance of snow leopards (Sharma et al., 2015; Suryawanshi et al., 2017), it was not the main predictor variable in our study. This could be because the length of the individual transects (1–2 km) was insufficient to encompass the vari- ability required for the model to detect the relationship, given the wide-ranging nature of snow leopards (Johansson et al., 2016). A temporal mismatch between bharal presence and the time when leopards left signs may also have obscured a direct relationship between the two
species. In the Qilian Shan region of China there was a weak association between prey and snow leopard site use at a fine scale (16 km2; Alexander et al., 2016b), but a strong positive relationship at a landscape scale (Alexander et al., 2016a). It is also possible that other factors, such as terrain ruggedness, which we could not measure (our sampling units were linear transects and it was not possible to compute a terrain ruggedness index adequately for such features), could have better explained the variability in sign encounter rate, as in Sagarmatha National Park, Nepal (Wolf & Ale, 2009). In Api Nampa Conservation Area snow leopards were
less likely to leave signs in areas of active human presence. Generally, large carnivores avoid using such areas, especially where hunting or harassment is common (Kerley et al., 2002). In our study area, although illegal resource extraction and hunting are prohibited, local herders disclosed that il- legal activities, such as use of snares to hunt bharal and pheasants Lophophorus impejanus, and collection of timber and non-timber forest products, occur frequently. This could be causing significant disturbance to snow leopards. In Sagarmatha National Park snow leopards were less likely to use trails used by tourists, guides or porters and their yak caravans (Wolf & Ale, 2009). We were unable to distinguish whether the greater sign
encounter rate that we found at higher elevations reflects greater site use or increased sign detection probability as a result of more snow accumulation and greater retention time of signs. Higher elevations are often more remote and less visited by people. A study of the fine scale occur- rence of snow leopards in Qilian Shan, China, found that the probability of site use by snow leopards increased with altitude (Alexander et al., 2016a).
TABLE 4 Bharal population structure in Api Nampa Conservation Area (Fig. 1) in October–November 2014.
Study block Adult male Subadult male Young male Female Yearling Young Total Area (km2) Density (per km2) Tinkar
Nampa Ghusa Sitaula
14 12 15 1
Khandewori 7 Rapla Total
6 55
20 12 12 1 5 4
54
21 8 9 0 6 3
47
73 51 39 3
21 15
202
27 16 18 2 7 7
77 Oryx, 2020, 54(3), 421–428 © 2018 Fauna & Flora International doi:10.1017/S0030605318000145
35 25 18 2 5 7
92
190 124 111 9
51 42
50 40 37 15 31 27
527 200
3.8 3.1 3
0.6 1.6 1.5
2.28
Relative variable importance 1.00
0.98 0.38
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