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Ale, S., & Whelan, C. (2008). Reappraisal of the role of big, fierce predators.
Abstract: The suggestion in the early 20th century that top predators were a necessary component of ecosystems because they hold herbivore populations in check and promote biodiversity was at Wrst accepted and then largely rejected. With the advent of Evolutionary Ecology and a more full appreciation of direct and indirect effects of top predators, this role of top predators is again gaining acceptance. The previous views were predicated upon lethal effects of predators but largely overlooked their non-lethal effects. We suggest that
conceptual advances coupled with an increased use of experiments have convincingly demonstrated that prey experience costs that transcend the obvious cost of death. Prey species use adaptive behaviours to avoid predators, and these behaviours are not cost-free. With predation risk, prey species greatly restrict their use of available habitats and consumption of available food resources. Effects of top predators consequently cascade down to the trophic levels below them. Top predators, the biggies, are thus both the targets of and the means for conservation at the landscape scale. |
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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. 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
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Suryawanshi, K. R., Bhatnagar, Y., & Mishra, C. (2009). Why should a grazer browse? Livestock impact on winter resource use by bharal Pseudois nayaur
. Oecologia, , 1–10.
Abstract: Many mammalian herbivores show a temporal diet variation between graminoid-dominated and browse dominated diets. We determined the causes of such a diet shift and its implications for conservation of a medium sized ungulate-the bharal Pseudois nayaur. Past studies show that the bharal diet is dominated by graminoids (>80%) during summer, but the contribution of graminoids declines to about 50% in winter. We tested the predictions generated by two alternative hypotheses explaining the decline: low graminoid availability during winter causes bharal to include browse in their diet; bharal include browse, with relatively higher nutritional quality, in their diet to compensate for the poor quality of graminoids during winter. We measured winter graminoid availability in areas with no livestock grazing, areas with relatively moderate livestock grazing, and those with intense livestock grazing pressures. The chemical composition of plants contributing to the bharal diet was analysed. The bharal diet was quantiWed through signs of feeding on vegetation at feeding locations. Population structures of bharal populations were recorded using a total count method. Graminoid availability was highest in areas without livestock grazing, followed by areas with moderate and intense livestock grazing. The bharal diet was dominated by graminoids (73%) in areas with highest graminoid availability. Graminoid contribution to the bharal diet declined monotonically (50, 36%) with a decline in graminoid availability. Bharal young to female ratio was 3 times higher in areas with high graminoid availability than areas with low graminoid availability. The composition of the bharal winter diet was governed predominantly by the availability of graminoids in the rangelands. Our results suggest that bharal include more browse in their diet during winter due to competition from livestock for graminoids. Since livestock grazing reduces graminoid availability, creation of livestock-free areas is necessary for the conservation of grazing species such as the bharal and its predators including the endangered snow leopard in the Trans-Himalaya.
Keywords: browse; livestock; impact; winter; resource; use; bharal; Pseudois; pseudois nayaur; Pseudois-nayaur; nayaur; diet; variation; diets; conservation; Media; study; decline; areas; area; grazing; Pressure; plants; plant; sign; feeding; location; population; structure; populations; using; young; Female; times; High; Competition; species; predators; predator; endangered; snow; snow leopard; snow-leopard; leopard; trans-himalaya; transhimalaya
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Schaller, G. B., Hong, L., Talipu, J., & Mingjiang, R. Q. (1988). The snow leopard in Xinjiang, China. Oryx, 22(4), 197–204.
Abstract: Snow leopards live in the mountains of Central Asia, their range stretching from Afganastan to Lake Baikal in Eastern Tibet. They are endangered throughout their range, being hunted as predators of mains livestock and for their skin. Much of the snow leopards range lies in China, but not enough is known about its staus there for effective conservation. As part of a project to assess China's high altitude wildlife resources the authors conducted a survey in Xinjiang- a vast arid region of deserts and mountains. Although the snow leopard and other wildlife have declined steeply in Xinjiang in recent decades, the cta still persists and one area has the potential to become one of the best refuges for the species in its entire range. Its future in XInjiang, howevere, depends on well protected reserves, enforcement of regulations against killing the animal, and proper managemnt of the prey species.
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Prakash, I. (1985). Asian predators of livestock. Parasites, pests and predators.World animal science, B2, 405–410.
Abstract: Outlines the distribution, status and predatory behaviour on livestock of Chinese alligator Alligator sinensis, gharial Gavialis gangeticus and several species of Crocodylus and Python; and of wolf Canis lupus, Asiatic jackal C. aureus, dhole (Indian wild dog) Cuon alpinus, brown bear Ursus arctos, Asiatic black bear Selenarctos thibetanus, striped hyaena Hyaena hyaena, clouded leopard Neofelis nebulosa, leopard (panther) Panthera pardus, tiger P. tigris, lion P. leo, snow leopard P. uncia, other Felidae and Viverridae. -P.J.Jarvis
Keywords: predators; asia; snow-leopard; livestock; status; prey; Panthera-uncia; distribution; predator; snow leopard; browse; panthera uncia; panthera; uncia; 870
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Jamtsho, Y., Katel, O. (2019). Livestock depredation by snow leopard and Tibetan wolf: Implications for herders� livelihoods in Wangchuck Centennial National Park, Bhutan. Springer Open, (9:1), 1–10.
Abstract: Human-wildlife conflict (HWC) is a serious problem in many parts of the world, and Bhutan�s Wangchuck Centennial
National Park (WCNP) is no exception. Located in the remote alpine areas of the eastern Himalaya, wildlife species such as snow leopard (SL) and Tibetan wolf (TW) are reported to kill livestock in many parts of the Park. Such depredation is believed to have affected the livelihoods of high-altitude herding communities, resulting in conflicts between them. This study provides analysis on the extent of livestock depredation by wildlife predators such as SL and TW and examines its implications for the livelihoods of herding communities of Choekhortoe and Dhur regions of WCNP. Using semi-structured questionnaires, all herders (n = 38) in the study area were interviewed. The questions pertained to livestock population, frequency of depredation and income lost due to depredation in the last five years from 2012 to 2016. This study recorded 2,815 livestock heads in the study area, with an average herd size of 74.1 stock. The average herd size holding showed a decreasing trend over the years, and one of the reasons cited by the herders is depredation by SL and TW and other predators. This loss equated to an average annual financial loss equivalent to 10.2% (US$837) of their total per capita cash income. Such losses have resulted in negative impacts on herders� livelihood; e.g. six herders (2012-2016) even stopped rearing livestock and resorted to an alternate source of cash income. The livestock intensification programmes, including pasture improvement through allowing controlled burning, and financial compensation, may be some potential short-term solutions to reduce conflict between herders and predators. Issuing permits for cordyceps (Ophiocordyceps sinensis) collection only to the herders and instilling the sense of stewardship to highland herders may be one of the long-term solutions. |