Summary1. 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 (0AE89, 0AE82, 0AE78, 0AE77) 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 ($6AE8% to $31AE8%) and small prey ($9% to $36%). 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.

Occupying only 7% of their historical range and confined to forested habitats interspersed in a matrix of human dominated landscapes, tigers (Panthera tigris) typify the problems faced by most large carnivores worldwide. With heads of governments of tiger range countries pledging to reverse the extinction process and setting a goal of doubling wild tiger numbers by 2022, achieving this target would require identifying existing breeding cores, potential breeding habitats and opportunities for dispersal. The Terai Arc Landscape (TAL) represents one region which has recently witnessed recovery of tiger populations following conservation efforts. In this study, we develop a spatially explicit tiger occupancy model with survey data from 2009–10 based on a priori knowledge of tiger biology and specific issues plaguing the western TAL (6,979 km2), which occurs in two disjunct units (Tiger Habitat Blocks; THBs). Although the overall occupancy of tigers was 0.588 (SE 0.071), our results clearly indicate that loss in functionality of a regional corridor has resulted in tigers now occupying 17.58% of the available habitat in THB I in comparison to 88.5% in THB II. The current patterns of occupancy were best explained by models incorporating the interactive effect of habitat blocks (AIC w = 0.883) on wild prey availability (AIC w = 0.742) and anthropogenic disturbances (AIC w = 0.143). Our analysis has helped identify areas of high tiger occupancy both within and outside existing protected areas, which highlights the need for a unified control of the landscape under a single conservation unit with the primary focus of managing tigers and associated wildlife. Finally, in the light of global conservation targets and recent legislations in India, our study assumes significance as we identify opportunities to secure (e.g. THB II) and increase (e.g. THB I) tiger populations in the landscape.

Summary1. The United Nations recently listed illegal wildlife trade as a serious crime because of the escalating demand for highly prized species, such as tiger and rhinoceros, and the failure to effectively control the trade. In turn, this places greater urgency on reducing supply by securing source populations of these species. Yet, whether law enforcement strategies designed to mitigate poaching are succeeding remains poorly understood, despite the millions of dollars invested annually in this mainstay conservation strategy. 2. Here, we assess the performance of one of Asia's longest running law enforcement programmes, from Kerinci Seblat National Park in Sumatra, by investigating whether forest ranger patrols reduced the occurrence of snare traps set for tiger and its ungulate prey base; local informant reports on poaching influenced ranger patrol success; and the resulting population trends of target species changed in response to these conservation actions. 3. A total of 4433 snare traps were removed during 642 foot patrols conducted from 2000 to 2010. Controlling for the influence of varying detection probabilities, as well as accessibility and other possible determinants of illegal hunting, revealed that sites with a greater frequency of patrols, rather than the combined distance walked, had a lower occurrence of snare traps in succeeding years. 4. Patrols conducted on the basis of local informant 'tip-offs' were significantly more likely to detect snare traps than routine patrols, with reports increasing detections by over 40%. 5. There were no significant changes in the occupancy status of the tiger prey base from 2004 to 2011, suggesting that it remained stable during this period. The relatively good condition of prey and predator populations in Kerinci Seblat National Park was further supported by the results of an independent survey conducted in 2008-2009 which revealed a widespread tiger occurrence. 6. Synthesis and applications. Our results not only demonstrate the effectiveness of the Kerinci Seblat law enforcement strategy in protecting wildlife, but highlight the benefits from cultivating a network of reliable informants. The study also represents a critical step in helping these urgently needed conservation assessments to become common place in the fight to save flagship species.