Snow leopard - prey dynamics
Understanding impact of wild prey availability on snow leopard killing livestock
Studies show that wild prey is the key determinant of snow leopard population, even in livestock dominant systems. Nonetheless, snow leopards depredate livestock opportunistically, often leading to retaliatory killing. Therefore, understanding this three-way dynamics holds huge ecological and conservation insights.
Persecution by farmers over livestock predation is one of the most important threats to the survival of large carnivores. At the same time, predation on livestock is a threat locally to agricultural security. Individual families may lose an equivalent of up to 50% of the average per capita income to livestock predation by carnivores, which can sometimes be high enough to keep affected people below poverty lines.
Increasing the abundance of wild prey populations is recommended as a policy to reduce carnivore predation on livestock. But, the impact of wild-prey availability on predation patterns of large carnivores is debatable. Theory predicts that, ultimately, the outcome of such a policy to increase wild prey abundance will depend on the shape and the strength of the responses of predator density (numerical response) and predator diet (functional response) to changes in prey density.
Snow leopard's survival is threatened, amongst other causes, due to persecution over its livestock killing behaviour. The reported contribution of livestock to snow leopard diet is variable and ranges from negligible to as high as 70%. Facilitating the recovery of wild ungulate prey of the snow leopard is considered an important measure to reduce the extent of livestock depredation.
Questions to be tested
Suryawanshi et al (2017) suggest that snow leopard population increases with wild herbivore population. This corroborates the pattern reported by Suryawanshi et al (2013) that farmers in areas with higher wild herbivore prey reported more instances of livestock predation by snow leopards. Here, we seek to understand whether the extent of livestock predation by snow leopards would increase or decline when there are changes in the abundance of wild herbivore prey or that of livestock. Into this model, we would like to also build in the understanding of direct competition between livestock and wild prey.
We will test our question by estimating snow leopard, wild herbivore and livestock density and the total number of livestock killed by snow leopards across 10 sites (each ~500 sq km) along a gradient of wild-prey to livestock ratios across the Indian Trans-Himalaya.
The specific methods for each of these data are:
1.Snow leopard density will be estimated using camera trap and SECR(spatially explicit capture-recapture) analysis across all sites
2.Wild herbivore prey density will be estimated using the double observer sampling method
3.Livestock population will be censused using interview surveys across all the villages in the study areas
4.We will identify key herders across all the sites to record all the livestock mortalities. We will measure the number of livestock killed by snow leopard through these data.
5.Impact of competition between livestock and wild herbivore prey will be modelled using our past data (Mishra et al. 2004; Suryawanshi et al. 2010)
The study is expected to result in some novel insights into the livestock predation behaviour of the snow leopard and the population ecology of predator, prey and livestock system. The results will be published in reputed international peer-reviewed journals. Since we are closely collaborating with the Himachal Pradesh Forest Department, we hope that the findings of this project will also find their way into the management plans of some of these regions. We work closely with the Central Government of India and other countries through our involvement in the Global Snow Leopard Ecosystem Protection (GSLEP).The expectation is that these findings will also help influence national and International policy for wildlife conservation in the snow leopard habitat of Central Asia.