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| Author | Suryawanshi, K.R. | ||||
| Title | Towards snow leopard prey recovery: understanding the resource use strategies and demographic responses of bharal Pseudois nayaur to livestock grazing and removal; Final project report | Type | Report | ||
| Year | 2009 | Publication | Abbreviated Journal | ||
| Volume | Issue | Pages | 1-43 | ||
| Keywords | project; snow; snow leopard; snow-leopard; leopard; network; conservation; program; prey; recovery; resource; use; strategy; demographic; Response; bharal; Pseudois; pseudois nayaur; Pseudois-nayaur; nayaur; livestock; grazing; Report; decline; wild; populations; population; Himalayan; region; Competition; threats; threat; uncia; Uncia uncia; Uncia-uncia; study; diet; winter; Test; browse; nutrition; areas; area; young; Female; times; High; Adult; mortality; species; predators; predator; endangered; trans-himalaya; transhimalaya | ||||
Abstract  |
Decline of wild prey populations in the Himalayan region, largely due to competition with livestock, has been identified as one of the main threats to the snow leopard Uncia uncia. Studies show that bharal Pseudois nayaur diet is dominated by graminoids during summer, but the proportion of graminoids declines in winter. We explore the causes for the decline of graminoids from bharal winter diet and resulting implications for bharal conservation. We test the predictions generated by two alternative hypotheses, (H1) low graminoid availability caused by livestock grazing during winter causes bharal to include browse in their diet, and, (H2) bharal include browse, with relatively higher nutrition, to compensate for the poor quality of graminoids during winter. Graminoid availability was highest in areas without livestock grazing, followed by areas with moderate and intense livestock grazing. Graminoid quality in winter was relatively lower than that of browse, but the difference was not statistically significant. Bharal diet was dominated by graminoids in areas with highest graminoid availability. Graminoid contribution to bharal diet declined monotonically with a decline in graminoid availability. Bharal young to female ratio was three times higher in areas with high graminoid availability than areas with low graminoid availability. No starvation-related adult mortalities were observed in any of the areas. Composition of bharal winter diet was governed predominantly by the availability of graminoids in the rangelands. Since livestock grazing reduces graminoid availability, creation of livestock free areas is necessary for conservation of grazing species such as the bharal and its predators such as the endangered snow leopard in the Trans-Himalaya. | ||||
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| Notes | Project funded by Snow Leopard Network's Snow Leopard Conservation Grant Program, 2008. Nature Conservation Foundation, Mysore. Post-graduate Program in Wildlife Biology and Conservation, National Centre for Biological Sciences, Wildlife Conservation Society -India program, Bangalore, India. | Approved | no | ||
| Call Number | SLN @ rana @ 1077 | Serial | 952 | ||
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| Author | Ale, S.; Brown, J. | ||||
| Title | The contingencies of group size and vigilance | Type | Miscellaneous | ||
| Year | 2007 | Publication | Evolutionary Ecology Research, | Abbreviated Journal | |
| Volume | 9 | Issue | Pages | 1263-1276 | |
| Keywords | attraction effect,contingency,dilution effect,fitness,group-size effect,many-eyes effect,predation risk,vigilance behaviour; predation; decline; potential; predators; predator; feeding; Animals; Animal; use; food; effects; Relationship; behaviour; methods; game; Interactions; interaction; factor; value; Energy | ||||
| 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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| Language | English | Summary Language | Original Title | ||
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| Notes | Approved | no | |||
| Call Number | SLN @ rana @ 886 | Serial | 53 | ||
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