Effects of incorporating competition between livestock and wild prey in the Indian Trans-Himalayan high-altitudes: A data-driven model

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Harman Jaggi, Biology, Stanford University, Stanford, CA, Sophie Smout, University of St. Andrews, St. Andrews, United Kingdom and Kulbhushan S Suryawanshi, Nature Conservation Foundation, Bangalore, India

Background/Question/Methods


Understanding prey dynamics are crucial for conservation of large carnivores. However, studies have shown that management interventions are often inadequately guided by ecological theory and rely on experiential decisions. In this study, we build a population model and draw implications for wild herbivores, predated upon by snow leopard (Panthera uncia), a vulnerable flagship species for conservation of wildlife in Central Asia’s mountain ranges. A major threat to their survival is the retaliatory persecution in defense of livestock. Facilitating native wild ungulate recovery is crucial for reducing the extent of livestock depredation. However, competitive interactions between livestock and wild herbivores and indirect effects may lead to different outcomes. We estimate the extent of competition between livestock and wild ungulates and predict how population dynamics are affected by changes in competition to better inform conservation outcomes and coexistence between humans, livestock, and wildlife.
We used double observer data to estimate abundance for wild prey- blue sheep (Pseudois nayaur) and ibex (Capra ibex), in the Trans-Himalaya of Himachal Pradesh, India. The sampling was carried at two long-term sites at Kibber (32.36° N; 78.01° E) and Pin (31.89° N; 77.94° E). The data on snow leopard abundance was collected using camera trapping, and on livestock abundance and depredation using interview surveys.
Results/Conclusions
Our results show there is significant competition between domestic and wild prey at both sites. The mean estimate for competition in Pin valley (0.027) is less than that of Kibber (0.138), by approximately an order of magnitude. This is consistent with our hypothesis because Pin Valley forms a natural habitat for ibex alone. Since ibex prefer steep slopes (<15), this might reduce resource limitation from domestic livestock. On the other hand, blue sheep prefer gentle slopes (>45 degree), paving way for greater habitat and dietary overlap with livestock. We simulated our model for different ranges of competition and found stable equilibrium even at high values. This may imply that livestock, wild prey, and snow leopards can co-exist but at high proportions of livestock, the wild prey densities are supressed. We also found switching parameter to be significantly greater than 1 (1.12 and 1.07 at Kibber and Pin) suggesting snow leopards display a weak Type III functional response. This finding corroborates with snow leopard diet study by Suryawanshi et al. 2017. Snow leopards may have the ability to switch, but they continue to take both prey even at high density of wild herbivores.