Ale, S., & Brown, J. (2007). The contingencies of group size and vigilance (Vol. 9).
Abstract: Background: Predation risk declines non-linearly with one's own vigilance and the vigilance of others in the group (the 'many-eyes' effect). Furthermore, as group size increases, the individual's risk of predation may decline through dilution with more potential victims, but may increase if larger groups attract more predators. These are known, respectively, as the dilution effect and the attraction effect.
Assumptions: Feeding animals use vigilance to trade-off food and safety. Net feeding rate declines linearly with vigilance.
Question: How do the many-eyes, dilution, and attraction effects interact to influence the relationship between group size and vigilance behaviour?
Mathematical methods: We use game theory and the fitness-generating function to determine the ESS level of vigilance of an individual within a group.
Predictions: Vigilance decreases with group size as a consequence of the many-eyes and dilution effects but increases with group size as a consequence of the attraction effect, when they act independent of each other. Their synergetic effects on vigilance depend upon the relative strengths of each and their interactions. Regardless, the influence of other factors on vigilance – such as encounter rate with predators, predator lethality, marginal value of energy, and value of vigilance – decline with group size.
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Ale, S. Conservation of the snow leopard in Nepal.
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Ale, S. B. (1994). Snow Leopard in Remote Districts of Nepal (Vol. xii). Seattle: Islt.
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Ale, S. B. (1997). The Annapurna Conservation Area Project: A Case Study of an Integrated Conservation and Development Project in Nepal. In R. Jackson, & A. Ahmad (Eds.), (pp. 155–169). Lahore, Pakistan: Islt.
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Ale, S. B. (1998). Religion and Snow Leopards in Nepal (Vol. xvi). Seattle: Islt.
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Ale, S., Shrestha, B., and Jackson, R. (2014). On the status of Snow Leopard Panthera Uncia (Schreber 1775) in Annapurna, Nepal. Journal of Threatened Taxa, (6(3)), 5534–5543.
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Ale, S. B., Yonzon, P., & Thapa, K. (2007). Recovery of snow leopard Uncia uncia in Sagarmatha (Mount Everest) National Park, Nepal (Vol. 41).
Abstract: From September to November 2004 we conducted surveys of snow leopard Uncia uncia signs in three major valleys in Sagarmatha (Mount Everest) National Park in Nepal using the Snow Leopard Information Management System, a standardized survey technique for snow leopard research. We walked 24 transects covering c. 14 km and located 33 sites with 56 snow leopard signs, and 17 signs incidentally in other areas. Snow leopards appear to have re-inhabited the Park, following their disappearance c. 40 years ago, apparently following the recovery of Himalayan tahr Hemitragus jemlahicus and musk deer Moschus chrysogaster populations. Taken together the locations of all 73 recent snow leopard signs indicate that the species is using predominantly grazing land and shrubland/ open forest at elevations of 3,000-5,000 m, habitat types that are also used by domestic and wild ungulates. Sagarmatha is the homeland of c. 3,500 Buddhist Sherpas with .3,000 livestock. Along with tourism and associated developments in Sagarmatha, traditional land use practices could be used to ensure coexistence of livestock and wildlife, including the recovering snow leopards, and ensure the wellbeing of the Sherpas.
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Tiwari, M. P., Devkota, B. P., Jackson, R. M., Chhetri, B. B.
K., Bagale, S. (2020). What Factors Predispose Households in Trans-Himalaya (Central
Nepal) to Livestock Predation by Snow Leopards? Animals, 10(2187), 1–14.
Abstract: Livestock depredation across the trans-Himalaya causes
significant economic losses to pastoralist communities. Quantification
of livestock predation and the assessment of variables associated with
depredation are crucial for designing effective long-term mitigation
measures. We investigated the patterns and factors of livestock
depredation by snow leopards (Panthera uncia) using semi-structured
questionnaires targeting herders in the Narphu valley of the Annapurna
Conservation Area, Nepal. During the two years (2017/18 and 2018/19),
73.9% of the households interviewed (n = 65) lost livestock to snow
leopards, with an annual average loss of two livestock per household. Of
the total depredation attributed to snow leopards, 55.4% were yak
(mainly female: 79%), 31.7% goat, 6.8% sheep, 3.2% horse and 2.8%
cattle. Results from applying Generalized Linear Mixed Models (GLMMs)
revealed the total number of livestock owned and the number of larger
bodied livestock species as the main explanatory covariates explaining
livestock depredation. Forty-one (41%) of all herders considered snow
leopard’s preference for domestic livestock as the main factor in
livestock predation, whereas only 5% perceived poor herding practice as
the main reason for the loss. Our study found poor and changing herding
practices in the valley, whereby 71% herders reported careful herding as
a solution to snow leopard depredation, and 15% of herders considered
the complete extermination of snow leopards as the best solution to the
problem. Tolerance levels and awareness among herders towards snow
leopard conservation is increasing, mainly due to the Buddhist religion
and strict law enforcement within this protected area. We recommend the
effective implementation of a community-based livestock insurance scheme
to compensate the economic loss of herders due to predation and improved
herding practices as the recommended mitigation measures for ensuring
livestock security and snow leopards’ conservation in the valley.
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Ale, S. B., Brown, J.S. (2009). Prey behavior leads to predator: a case study of the Himalayan tahr and the snow leopard in Sagarmatha (Mt. Everest) National Park, Nepal. Israel Journal of Ecology & Evolution, 55(4), 315–327.
Abstract: Rare, elusive predators offer few sightings, hindering research with small sample sizes and lack of experimentation. While predators may be elusive, their prey are more readily observed. Prey respond to the presence of a predator, and these fear responses may have population- and community-level consequences. Anti-predator behaviors, such as vigilance, allow us to sidestep the difficulty of direct field studies of large predators by studying them indirectly. Here we used a behavioral indicator, the vigilance behavior of the Himalayan tahr, the snow leopard’s main local prey, to reveal the distribution and habitat use of snow leopards in the Mt. Everest region of Nepal. We combined techniques of conventional field biology with concepts of foraging theory to study prey behavior in order to obtain insights into the predator’s ecology. The Himalayan tahr’s vigilance behavior correlates with the distribution of snow leopard signs. Tahr actually led us to six sightings of snow leopards. We conclude that behavioral indicators provided by prey offer a valuable tool for studying and monitoring stealthy and rare carnivores.
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Ale, S. B., Boesi, R. (2005). Snow Leopard Sightings on the Top of the World. Cat News, (43), 19–20.
Abstract: Sightings of snow leopards Uncia uncia in the wild are rare. This is because snow leopards occur in low numbers and are very elusive (Schaller 1977). Snow leopards may be sparsely distributed,but they may not, however, be very elusive in the world's highest park, Sagarmatha (Mt. Everest) National Park (86° 30' 53“ E to 86° 99' 08” E and 27° 46' 19“ N to 27° 06' 45” N) in Nepal.
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