Kanchan Thapa

Past, present and future conservation of the greater one-horned rhinoceros Rhinoceros unicornis in Nepal

Until the early 1980s the only surviving population of the greater one-horned rhinoceros Rhinoceros unicornis in Nepal was in Chitwan National Park. Between 1986 and 2003 87 rhinoceroses from Chitwan were translocated into Bardia National Park and Suklaphanta Wildlife Reserve in the western terai region to establish founder populations and reduce the threat of local extinction from natural catastrophic events, disease and/or poaching. The founder populations increased in number through births but a rise in poaching during the period of civil strife in Nepal during 1996–2006 resulted in a dramatic decline in the populations, including in Chitwan. In 2001 the Terai Arc Landscape programme was initiated to connect 11 protected areas in Nepal and north-west India and facilitate dispersal of megafauna and manage them as metapopulations. Corridors that were restored under the programme and that connect Bardia and Suklaphanta with protected areas in India are now used by the greater one-horned rhinoceros. The successes and failures of the last 2 decades indicate that new paradigms for protecting rhinoceroses within and outside protected areas are needed, especially with reference to managing this species at a landscape scale.

Leopard Panthera pardus fusca Density in the Seasonally Dry, Subtropical Forest in the Bhabhar of Terai Arc, Nepal

We estimated leopard (Panthera pardus fusca) abundance and density in the Bhabhar physiographic region in Parsa Wildlife Reserve, Nepal. The camera trap grid, covering sampling area of 289 km2 with 88 locations, accumulated 1,342 trap nights in 64 days in the winter season of 2008-2009 and photographed 19 individual leopards. Using models incorporating heterogeneity, we estimated 28 (±SE 6.07) and 29.58 (±SE 10.44) leopards in Programs CAPTURE and MARK. Density estimates via 1/2 MMDM methods were 5.61 (±SE 1.30) and 5.93 (±SE 2.15) leopards per 100 km2 using abundance estimates from CAPTURE and MARK, respectively. Spatially explicit capture recapture (SECR) models resulted in lower density estimates, 3.78 (±SE 0.85) and 3.48 (±SE 0.83) leopards per 100 km2, in likelihood based program DENSITY and Bayesian based program SPACECAP, respectively. The 1/2 MMDM methods have been known to provide much higher density estimates than SECR modelling techniques. However, our SECR models resulted in high leopard density comparable to areas considered better habitat in Nepal indicating a potentially dense population compared to other sites. We provide the first density estimates for leopards in the Bhabhar and a baseline for long term population monitoring of leopards in Parsa Wildlife Reserve and across the Terai Arc.

Density and carrying capacity in the forgotten tigerland: Tigers in the understudied Nepalese Churia

While there are numerous wildlife ecology studies in lowland areas of Nepal, there are no in-depth studies of the hilly Churia habitat even though it comprises 7642 km2 of potential wildlife habitat across the Terai Arc. We investigated tiger, leopard and prey densities across this understudied habitat. Our camera trapping survey covered 536 km2 of Churia and surrounding areas within Chitwan National Park (CNP). We used 161 trapping locations and accumulated 2097 trap-nights in a 60-day survey period during the winter season of 2010-2011. In addition, we walked 136 km over 81 different line transects using distance sampling to estimate prey density. We photographed 31 individual tigers, 28 individual leopards and 25 other mammalian species. Spatial capture-recapture methods resulted in lower density estimates for tigers, ranging from 2.3 to 2.9 tigers per 100 km2 , than for leopards, which ranged from 3.3 to 5.1 leopards per 100 km2 . In addition, leopard densities were higher in the core of the Churia compared to surrounding areas. We estimated 62.7 prey animals per 100 km2 with forest ungulate prey (sambar, chital, barking deer and wild pig), accounting for 47% of the total. Based on prey availability, Churia habitat within CNP could potentially support 5.86 tigers per 100 km2 but our density estimates were lower, perhaps indicating that the tiger population is below carrying capacity. Our results demonstrate that Churia habitat should not be ignored in conservation initiatives, but rather management efforts should focus on reducing human disturbance to support higher predator numbers.

Assessment of genetic diversity, population structure, and gene flow of tigers (Panthera tigris tigris) across Nepal's Terai Arc Landscape

With fewer than 200 tigers (Panthera tigris tigris) left in Nepal, that are generally confined to five protected areas across the Terai Arc Landscape, genetic studies are needed to provide crucial information on diversity and connectivity for devising an effective country-wide tiger conservation strategy. As part of the Nepal Tiger Genome Project, we studied landscape change, genetic variation, population structure, and gene flow of tigers across the Terai Arc Landscape by conducting Nepal’s first comprehensive and systematic scat-based, non-invasive genetic survey. Of the 770 scat samples collected opportunistically from five protected areas and six presumed corridors, 412 were tiger (57%). Out of ten microsatellite loci, we retain eight markers that were used in identifying 78 individual tigers. We used this dataset to examine population structure, genetic variation, contemporary gene flow, and potential population bottlenecks of tigers in Nepal. We detected three genetic clusters consistent with three demographic sub-populations and found moderate levels of genetic variation (He = 0.61, AR = 3.51) and genetic differentiation (FST = 0.14) across the landscape. We detected 3–7 migrants, confirming the potential for dispersal-mediated gene flow across the landscape. We found evidence of a bottleneck signature likely caused by large-scale land-use change documented in the last two centuries in the Terai forest. Securing tiger habitat including functional forest corridors is essential to enhance gene flow across the landscape and ensure long-term tiger survival. This requires cooperation among multiple stakeholders and careful conservation planning to prevent detrimental effects of anthropogenic activities on tigers.

Tigers in the Terai: Strong evidence for meta-population dynamics contributing to tiger recovery and conservation in the Terai Arc Landscape

The source populations of tigers are mostly confined to protected areas, which are now becoming isolated. A landscape scale conservation strategy should strive to facilitate dispersal and survival of dispersing tigers by managing habitat corridors that enable tigers to traverse the matrix with minimal conflict. We present evidence for tiger dispersal along transboundary protected areas complexes in the Terai Arc Landscape, a priority tiger landscape in Nepal and India, by comparing camera trap data, and through population models applied to the long term camera trap data sets. The former showed that 11 individual tigers used the corridors that connected the transboundary protected areas. The estimated population growth rates using the minimum observed population size in two protected areas in Nepal, Bardia National Park and Suklaphanta National Park showed that the increases were higher than expected from growth rates due to in situ reproduction alone. These lines of evidence suggests that tigers are recolonizing Nepal’s protected areas from India, after a period of population decline, and that the tiger populations in the transboundary protected areas complexes may be maintained as meta-population. Our results demonstrate the importance of adopting a landscape-scale approach to tiger conservation, especially to improve population recovery and long term population persistence.

The Terai Arc Landscape

Publisher Summary The Terai is one of the most fragmented and threatened ecosystems in Asia. The large mammals of the Terai are mostly confined to the protected areas, although the ecological and behavioral traits of these species demand extensive habitat areas for effective, long-term conservation. The conservation challenge in the Terai is to manage and maintain ecologically, demographically, and genetically viable populations of the Terais endangered megaspecies. To achieve this goal, a coalition of governmental and non-governmental partners from Nepal and India adopted a landscape-scale conservation strategy to connect twelve protected areas across the Himalayan foothills with habitat linkages to facilitate species dispersal and seasonal movements. Since the tiger is an important focal species in the Terai, the linkages are identified based on its ecological requirements and behavioral characteristics. This chapter reveals that a strategy that elicits local stewardship to link core refuges for conservation of tigers and other iconic megaspecies of Asia, which are losing ground against the human tide, is possible even in human-dominated landscapes. Humans and wildlife have co-existed for millennia in Asia, and people who have traditionally lived with wildlife in their backyards are usually tolerant to some degree of depredation and crop damage. Therefore, if conflict can be maintained at low levels, and both people and wildlife can share the benefits of conservation, there can be scope for their co-existence.Publisher Summary The Terai is one of the most fragmented and threatened ecosystems in Asia. The large mammals of the Terai are mostly confined to the protected areas, although the ecological and behavioral traits of these species demand extensive habitat areas for effective, long-term conservation. The conservation challenge in the Terai is to manage and maintain ecologically, demographically, and genetically viable populations of the Terais endangered megaspecies. To achieve this goal, a coalition of governmental and non-governmental partners from Nepal and India adopted a landscape-scale conservation strategy to connect twelve protected areas across the Himalayan foothills with habitat linkages to facilitate species dispersal and seasonal movements. Since the tiger is an important focal species in the Terai, the linkages are identified based on its ecological requirements and behavioral characteristics. This chapter reveals that a strategy that elicits local stewardship to link core refuges for conservation of tigers and other iconic megaspecies of Asia, which are losing ground against the human tide, is possible even in human-dominated landscapes. Humans and wildlife have co-existed for millennia in Asia, and people who have traditionally lived with wildlife in their backyards are usually tolerant to some degree of depredation and crop damage. Therefore, if conflict can be maintained at low levels, and both people and wildlife can share the benefits of conservation, there can be scope for their co-existence.