Responses of leopard Panthera pardus to the recovery of a tiger Panthera tigris population

Abstract

Summary 1. Several conservation initiatives are aiming to improve the status of the rapidly dwindling populations of tiger Panthera tigris. However, possible cascading effects of intra-guild competition on other sympatric carnivores are rarely considered while planning such recovery programmes. 2. In this study, we examine how, following the reduction of anthropogenic pressures by relocation of pastoralists, a recovering tiger population affects leopards Panthera pardus in the Chilla Range of Rajaji National Park (RNP), India. By combining data gathered over 4 years (2004–2005 to 2007–2008) on prey availability, food habits and population density of the two predators, we investigate some of the mechanisms of niche partitioning. 3. Based on existing information, we predicted that there would be high dietary overlap between the two predators. Over time, optimal habitats would be dominated by tigers forcing leopards to the periphery of the protected area where they would subsist on small prey and domestic livestock. Consequently, leopards would occur at a lower density where sympatric with tigers. 4. Our results confirmed that annual dietary overlap (0·89, 0·82, 0·78, 0·77) between the two predators was high during the study. As expected, we observed a shift in the diet of leopards towards a significantly higher intake of domestic prey (∼6·8% to ∼31·8%) and small prey (∼9% to ∼36%). Mean leopard density declined from 9·76 animals per 100 km2 in 2004–2005 to 2·07 per 100 km2 in 2007–2008, while the mean density of tigers increased from 3·31 per 100 km2 to 5·81 per 100 km2 over the same period. 5. Synthesis and applications. Although based on small sample sizes, our study revealed that over the 4 years following the relocation of pastoralists out of RNP, the tiger population recovered but leopard densities declined sharply. The concurrent shift in leopard diet indicated heightened livestock depredation from the surrounding area. Therefore, it is important that conservation initiatives targeting the recovery of tigers should be preceded by careful examination of interspecific interactions with sympatric carnivores. Comprehensive human–carnivore conflict management measures like monitoring the extent of livestock depredation, improving livestock management and providing adequate compensation and/or insurance schemes are critical for successfully implementing such conservation efforts.