Ecology of the snow leopard and the Himalayan tahr in Sagarmatha (Mt. Everest) National Park, Nepal

The distribution and abundance of snow leopards Uncia uncia and Himalayan tahr Hemitragus jemlahicus were studied in the Mt. Everest region of Nepal, from 2004 to 2006. Techniques of old-fashioned, mud-and-boots field biology were used in combination with cutting-edge techniques using theories of foraging and anti-predatory vigilance of prey (Himalayan tahr) to assess the status and the habitat use patterns of snow leopards. Himalayan tahr vigilance behavior correlated tightly with the abundance and distribution of snow leopard signs. This study confirmed that snow leopards have returned to the Mt. Everest region following their disappearance some 40 years ago, in response to the increasing population of Himalayan tahr.;Two concepts central to foraging theory involving predation risk were modeled and extended: One, how animals should select their habitats under predation risk and, two, once within a selected habitat, how foraging animals should partition time between competing fitness enhancing activities. Incorporating predation risk, the first model extended the theory of density-dependent habitat selection model based on the ideal free distribution. The second work, a game theory model of group size and vigilance, demonstrated how group membership can influence predation risk and the value of vigilance. The model revealed that group size effect on vigilance behavior is contingent upon the strength of interacting effects of many eyes, dilution and predation-attraction effects.;The growing claim that top predators structure communities was explored from historical perspectives. A few major ecological paradigms were also examined in the context of their relevance to biodiversity conservation.