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Most endangered species exist today in small populations, many of which are isolated. Evolution in such populations is largely governed by genetic drift. Empirical evidence for drift affecting striking phenotypes based on substantial genetic data are rare. Approximately 37% of tigers (Panthera tigris) in the Similipal Tiger Reserve (in eastern India) are pseudomelanistic, characterized by wide, merged stripes. Camera trap data across the tiger range revealed the presence of pseudomelanistic tigers only in Similipal. We investigated the genetic basis for pseudomelanism and examined the role of drift in driving this phenotype's frequency. Whole-genome data and pedigree-based association analyses from captive tigers revealed that pseudomelanism cosegregates with a conserved and functionally important coding alteration in Transmembrane Aminopeptidase Q (Taqpep), a gene responsible for similar traits in other felid species. Noninvasive sampling of tigers revealed a high frequency of the Taqpep p.H454Y mutation in Similipal (12 individuals, allele frequency = 0.58) and absence from all other tiger populations (395 individuals). Population genetic analyses confirmed few (minimal number) tigers in Similipal, and its genetic isolation, with poor geneflow. Pairwise FST (0.33) at the mutation site was high but not an outlier. Similipal tigers had low diversity at 81 single nucleotide polymorphisms (mean heterozygosity = 0.28, SD = 0.27). Simulations were consistent with founding events and drift as possible drivers for the observed stark difference of allele frequency. Our results highlight the role of stochastic processes in the evolution of rare phenotypes. We highlight an unusual evolutionary trajectory in a small and isolated population of an endangered species.

India led the global tiger conservation initiatives since last decade and has doubled its wild tiger population to 2967 (2603-3346). The survival of these growing populations residing inside the continuously shrinking habitats is a major concern, which can only be tackled through focused landscape-scale conservation planning across five major extant Indian tiger landscapes. The Terai-Arc landscape (TAL) is one of the ‘global priority’ tiger conservation landscapes holding 22% of the country’s wild tigers. We used intensive field-sampling, genetic analyses and GIS modelling to investigate tiger population structure, source-sink dynamics and functionality of the existing corridors across TAL. Genetic analyses with 219 tigers revealed three low, but sigficantly differentiated tiger subpopulations. Overall, we identified Seven source and 10 sink areas in TAL through genetic migrant and gene flow analyses. GIS modelling identified total 19 (10 high, three medium and six low conductance) corridors in this landscape, with 10 being critical to maintain landscape connectivity. We suggest urgent management attention towards 2707 sq. km. non-protected habitat, mitigation measures associated with ongoing linear infrastructure developments and transboundary coordination with Nepal to ensure habitat and genetic connectivity and long-term sustainability of tigers in this globally important landscape.

The swamp deerRucervus duvauceliiis the largest grassland-dwelling endemic cervid of India and Nepal. With a declining population trend across its range, this species is found in fragmented habitats of northern, north-eastern and central India and south-western Nepal. The northern swamp deer subspeciesRucervus duvaucelii duvauceliioccurs in small wetland patches across the states of Uttarakhand and Uttar Pradesh in India and has lost most of its habitat in the last century. Information about the distribution of the swamp deer in the upper Gangetic plains is limited, except in the Jhilmil Jheel Conservation Reserve in Uttarakhand and around the Bijnor barrage area of Hastinapur Wildlife Sanctuary in Uttar Pradesh. We surveyed the upper Gangetic plains between the Reserve and the Sanctuary, including some adjoining areas and three tributaries of the Ganges, to assess the status of these habitats, current swamp deer distribution and the threats faced by the species. We found several areas harbouring swamp deer within non-protected wetlands along the entire surveyed stretch of the upper Ganges and a previously unreported population in Uttar Pradesh. We documented major threats including habitat conversion, livestock grazing, poaching, conflict and other anthropogenic disturbances. We recommend community driven conservation and management ofRucervus duvaucelii duvauceliiin this fragmented landscape to ensure survival of this species and other threatened fauna of these wetlands and grasslands.

Anthropogenic disturbance and climate change have significantly affected the distribution of wetlands globally and particularly in Asian countries. Various types of wetlands are harboured across all the biogeographic zones in India. These wetlands provide vital ecological services and are rich in biodiversity. However, anthropogenic pressures continue to be a threat to these wetlands by affecting the flora and fauna that depend on them. Tree-nesting colonial waterbirds are vulnerable to these pressures as their colonies are typically located in wetlands and associated areas. Disturbances to these areas have resulted in the loss or shifting of many heronries. The present study was conducted in the Indian state of Tamil Nadu during the period of 2017–2019 to document the existing and previously unknown heronries of the landscape. A total of 101 heronries were documented in 22 districts. The Little Cormorant was the most dominant species, occurring in 79% of the sites, with relative abundances of 24% and 26% during 2017–2018 and 2018–2019, respectively. A total of 23 tree species were utilized by the birds for nesting and Vachellia nilotica trees were used for nesting in about 25% of the heronries. 19% of the heronries were situated inside protected areas and 81% were located outside protected areas. Out of the 58 active nesting sites reported in 2005, 43 have been lost or are no longer active. Species distribution modelling with presence only data indicated that the sites with a high probability of occurrence were confined to the major waterbodies and rivers. Spatial correlation showed that the heronries were dispersed randomly across the landscape. The population dynamics within heronries and colonial nesting waterbirds’ response to various environmental factors must be monitored continuously to conserve these heronries.

BackgroundLarge carnivores maintain the stability and functioning of ecosystems. Currently, many carnivore species face declining population sizes due to natural and anthropogenic pressures. The leopard,Panthera pardus, is probably the most widely distributed and highly adaptable large felid globally, still persisting in most of its historic range. However, we lack subspecies-level data on country or regional scale on population trends, as ecological monitoring approaches are difficult to apply on such wide-ranging species. We used genetic data from leopards sampled across the Indian subcontinent to investigate population structure and patterns of demographic decline.MethodsWe collected faecal samples from the Terai-Arc landscape of northern India and identified 56 unique individuals using a panel of 13 microsatellite markers. We merged this data with already available 143 leopard individuals and assessed genetic structure at country scale. Subsequently, we investigated the demographic history of each identified subpopulations and compared genetic decline analyses with countrywide local extinction probabilities.ResultsOur genetic analyses revealed four distinct subpopulations corresponding to Western Ghats, Deccan Plateau-Semi Arid, Shivalik and Terai region of the north Indian landscape, each with high genetic variation. Coalescent simulations with microsatellite loci revealed a possibly human-induced 75–90% population decline between ∼120–200 years ago across India. Population-specific estimates of genetic decline are in concordance with ecological estimates of local extinction probabilities in these subpopulations obtained from occupancy modeling of the historic and current distribution of leopards in India.ConclusionsOur results confirm the population decline of a widely distributed, adaptable large carnivore. We re-iterate the relevance of indirect genetic methods for such species in conjunction with occupancy assessment and recommend that detailed, landscape-level ecological studies on leopard populations are critical to future conservation efforts. Our approaches and inference are relevant to other widely distributed, seemingly unaffected carnivores such as the leopard.

Large carnivores maintain the stability and functioning of ecosystems. Currently, many carnivore species face declining population sizes due to natural and anthropogenic pressures. The leopard,Panthera pardus, is probably the most widely distributed and adaptable large carnivore, still persisting in most of its’ historic range. However, we lack subspecies level data on country or regional scale on population trends, as ecological monitoring approaches are difficult to apply on such wide-ranging species. We used genetic data from leopards sampled across the Indian subcontinent to investigate population structure and patterns of demographic decline. Our genetic analyses revealed four distinct subpopulations corresponding to Western Ghats, Deccan Plateau-Semi Arid, Shivalik and Terai region of north Indian landscapes, each with high genetic variation. Coalescent simulations with 13 microsatellite loci revealed a 75-90% population decline in between 120-200 years ago across India, possibly human induced. Population-specific estimates of genetic decline are in concordance with ecological estimates of local extinction probabilities in four sub-populations obtained from occupancy modelling of historic and current distribution of leopards in India. Our results confirm population decline of a widely distributed, adaptable large carnivore. We re-iterate the relevance of indirect genetic methods for such species, and recommend that detailed, landscape-level ecological studies on leopard populations are critical to future conservation efforts. Our approaches and inference are relevant to other widely distributed, seemingly unaffected carnivores such as the leopard.

Burgeoning pressures of habitat loss is a major cause of herbivore decline across India, forcing them to coexist with humans in non-protected areas. Their conservation in such landscapes is challenging due to paucity of ecological and demographic information. The northern subspecies of swamp deer, Rucervus duvaucelii duvaucelii, is one such herbivore that lives across human-dominated landscapes in Terai region and upper Gangetic plains of north India. Here, we describe species-specific molecular markers and a cervid-specific molecular sexing assay for swamp deer and four other coexisting cervids sambar, chital, barking deer and hog deer. Our markers show species-specific band patterns and a high success rate of 88.21% in large number of field collected reference samples for all species. Faecal pellets from pilot swamp deer survey samples from upper Ganges basin show 93.81% success rate, and only 5.5% misidentification based on morphological characteristics. Our cervid-specific molecular sexing multiplex assay accurately ascertained 81.15% samples to respective sexes. These molecular approaches provide an easy, quick and cheap option to generate critical information on herbivore population parameters and aid their conservation in this mosaic of protected and non-protected grassland habitats.

Efforts are on to recover tiger populations range-wide, but we lack suitable metrics to characterise and evaluate such recoveries. Identifying such metrics requires an understanding of tiger population dynamics and its ecological correlates in either recovering populations or those exposed to anthropogenic influences. We monitored a recovering tiger population from 2004 to 2017 in Rajaji National Park, India. Using photographic data and spatial capture-recapture models in an inviolate site vacated by pastoralists (zone 1), we identified demographic parameters of a recovering population. By contrasting it with a site that is presently occupied by pastoralists (zone 3) and one that is isolated (zone 3), we identified conditions facilitating recovery. In zone 1, connected to a large source population in Corbett Tiger Reserve, density increased from 2.08 tigers/100 km2 to 7.07 tigers/100 km2 corresponding to an annual growth rate of 4.5%. Density also increased in zone 2 (2.6 tigers/100 km2 to 6.22 tigers/100 km2), but estimated apparent survival was 0.47 against 0.81 in zone 1. Recovery in zone 1 was accompanied by increased survival of females, while female tenure was shorter in zone 2. Due to the lack of functional connectivity, tigers in zone 3 are facing local extinction. Our results demonstrate that creating inviolate spaces to secure breeding populations and maintaining landscape-wide connectivity to expand breeding cores is critical for recovery. We highlight that relying solely on population increase may lead to unreliable inferences about population performance and instead suggest tracking survival and female land tenure to qualify recovery and success of conservation interventions.

Recent declines in large herbivores have led to significant conservation efforts globally. However, the niche-specific megaherbivores residing outside protected areas face more imminent extinction threats. Swamp deer, the obligate grassland-dwelling endemic cervid is the most extinction-prone megaherbivore in the Indian subcontinent. Limited information on distribution and habitat status pose significant conservation and management challenges for the remaining fragmented populations in north, north-east and central India. To this end, we combined exhaustive field surveys and Maximum Entropy (MaxEnt) modeling to generate the most detailed distribution map for the northern swamp deer subspecies. We used primary data from more than 6000 km2 field surveys and eight ecologically relevant covariates for model predictions. Grassland cover, annual mean temperature and distance from water were the major factors that predicted the species distribution. Models predicted swamp deer distribution in only ~3% of the entire landscape, covering both protected (~1.4%) as well as non-protected (~1.6%) areas. Our validation surveys in some of these predicted areas confirmed swamp deer presence and indicated ~85% model accuracy. Finally, we identified four ‘Priority Conservation Areas’ still retaining adequate grassland habitat and species presence that require immediate attention to ensure population connectivity across this landscape. These results highlight the importance of the marginalized grassland ecosystems of northern India that still retains high biodiversity. We suggest a swamp deer-centric conservation approach to protect these human-dominated habitats and emphasize in generating such information for other endemic, habitat-specialist species across the globe.

Information on the abundance of tigers Panthera tigris is essential for effective conservation of the species. The main aim of this study was to determine the status of tigers in Chitwan National Park, Nepal, including the Churia hills, using a camera-trap based mark–recapture abundance estimate. Camera traps (n = 310) were placed in an area of 1,261 km2 from 20 January to 22 March 2010. The study area was divided into three blocks and each block was trapped for 19–21 days, with a total effort of 3,582 man-days, 170 elephant-days and 4,793 camera-trap nights. The effectively camera-trapped area was 2,596 km2. Camera stations were located 1.5–2 km apart. Sixty-two tigers (age ⩾ 1.5 years), comprising 15 males, 41 females and six of unidentified sex, were identified from 344 photographs. The heterogeneity model Mh (jackknife) was the best fit for the capture history data. A capture probability ($\hat P$) of 0.05 was obtained, generating a population estimate ($\hat N$) of 125 ± SE 21.8 tigers. The density of tigers in the area, including Churia and Barandabhar (buffer zone forest linked with mid hill forest), was estimated to be 4.5 ± SE 0.35 tigers per 100 km2, using a Bayesian spatially explicit capture–recapture model in SPACECAP. Our study showed the use of Churia by tigers and we therefore conclude that the Chitwan tiger population serves as a source to maintain tiger occupancy of the larger landscape that comprises Chitwan National Park, Parsa Wildlife Reserve, Barandabhar buffer zone, Someswor forest in Nepal and Valmiki Tiger Reserve in India.

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.

In an unprecedented response to the rapid decline in wild tiger populations, the Heads of Government of the 13 tiger range countries endorsed the St. Petersburg Declaration in November 2010, pledging to double the wild tiger population. We conducted a landscape analysis of tiger habitat to determine if a recovery of such magnitude is possible. The reserves in 20 priority tiger landscapes can potentially support >10,000 tigers, almost thrice the current estimate. However, most core reserves where tigers breed are small and land-use change in rapidly developing Asia threatens to increase reserve and population isolation. Maintaining population viability and resilience will depend upon a landscape approach to manage tigers as metapopulations. Thus, both site-level protection and landscape-scale interventions to secure habitat corridors are simultaneous imperatives. Co-benefits, such as payment schemes for carbon and other ecosystem services, should be employed as strategies to mainstream landscape conservation in tiger habitat into development processes.

Olive ridley mass nesting events or ‘arribadas’ have been documented in Orissa, India since 1974.However, since standardised techniques have not been used to census turtles, actual population trends remain unknown.Herein, we summarise information on nesting populations in Orissa, using data from multiple sources to arrive at consensus estimates and to derive trends.We conducted a quantitative estimate of an arribada in March 1999, where nesting was estimated as � 180,000 turtles by the strip transect method. Non-linear (quadratic) fits for arribada data from 1976–1999 and a recent decrease in the size of adults suggest a potential or imminent decline, consistent with fishery-related mortality of at least 90,000 turtles since 1994.Though statistical support for the recent decline is equivocal, efforts to reduce mortality and close monitoring of the population would be prudent.The absence of reliable data on which to base conservation action highlights an urgent need to train management personnel in data collection and estimation techniques for effective monitoring of status, threats and trends. # 2003 Elsevier Ltd.All rights reserved.

Aim\ud Setting realistic population targets and identifying actions for site and landscape-level recovery plans are critical for achieving the global target of doubling wild tiger numbers by 2022. Here, we estimate the spatially explicit densities of wild ungulate prey across a gradient of disturbances in two disjunct tiger habitat blocks (THBs) covering 5212 km2, to evaluate landscape-wide conditions for tigers and identify opportunities and specific actions for recovery.\ud \ud Location\ud Western Terai Arc Landscape, India.\ud \ud Methods\ud Data generated from 96 line transects in 15 systematically selected geographical cells (166.5 km2) were used to estimate spatially explicit densities of six wild ungulate prey species at a fine scale (1 km2). Employing distance-based density surface models, we derived species-specific estimates within three major forest land management categories (inviolate protected areas (PA), PAs with settlements and multiple-use forests). By scaling estimated prey densities using an established relationship, we predicted the carrying capacity for tigers within each THB.\ud \ud Results\ud Species-specific responses of the six wild ungulates to natural-habitat and anthropogenic covariates indicated the need for targeted prey recovery strategies. Inviolate PAs supported the highest prey densities compared with PAs with settlements and multiple-use forests, and specifically benefited the principal tiger prey species (chital Axis axis and sambar Rusa unicolor). The estimated mean prey density of 35.16 (±5.67) individuals per km2 can potentially support 82 (62–106) and 299 (225–377) tigers across THB I and THB II, which currently support 2 (2–7) and 225 (199–256) tigers, respectively. This suggests a potential c. 68% increase in population size given existing prey abundances. Finally, while THB I represents a potential tiger recovery site given adequate prey, PAs where resettlement of pastoralists is underway represent potential prey recovery sites in THB II.\ud \ud Main conclusions\ud This systematic approach of setting realistic population targets and prioritizing spatially explicit recovery strategies should aid in developing effective landscape conservation plans towards achieving global tiger conservation targets.

Publisher Summary The tiger ( Panthera tigris ) originated in the landscape that is now China, and was widely distributed over Southeast Asia even about two million years ago. Although no historical data exist on tiger population sizes, old hunting records provide valuable insights into their abundance in the past. To save the tiger in remaining habitats, priority landscapes need to be identified where conservation efforts can be focused to secure breeding habitats connected by functional corridors. Poaching, both of prey and tigers, needs to be controlled. Programs to reduce the dependence of people on the surrounding wildlife habitats need to be promoted, and feral dogs that might kill wild ungulates and deter tigers need to be eliminated. There is increasing analytical sophistication and greater reliability in approaches to prioritize landscapes for global tiger conservation. The development of a synthetic toolbox of conservation approaches that draw on the social, economic, political, and institutional complexities of on-ground tiger conservation across various regions is an essential baseline for tiger conservation that is currently missing.

Linnaeus)over most of their range. While considerable conserva-tion investment is primarily targeted towards recoveringthe dwindling populations of tigers (Dinerstein et al.2007), our understanding of the potentially cascadingeffects of human-induced changes to populations of onecarnivore species on the entire carnivore community(Smith et al. 2003) remains poor. Though leopards maynot be as adversely affected as tigers under deterioratinghabitat conditions (Ramakrishnan et al. 1999), the con-tinual loss of habitat and intense poaching for illegaltrade in body parts (Environmental Investigation Agency(EIA) and Wildlife Protection Society of India (WPSI)2006)has caused a decline in their population. However, thelack of estimates of population size makes it difficult tomake an objective assessment of their status.The Chilla forest range (148 km

Rajaji National Park, which forms the north-western limit of the range of the tiger Panthera tigris in India, is bisected into western and eastern sectors by development activities along the banks of the river Ganga. Following a voluntary pastoral Gujjar resettlement programme initiated in the Park by the Uttarakhand Forest Department, we assessed the status of the tiger and its prey. We used sign surveys for tigers, leopards Panthera pardus and their prey, estimated prey densities using line transects and distance sampling, and estimated the density of tigers using photographic capture-recapture analysis. Our results indicate that the use of the area by tigers differed significantly between the two sectors of the Park, with pug mark encounter rates per 250 m segment from sign surveys of 0.07 ± SE 0.04 in the west and 1.6 ± SE 0.3 in the east. Although the high estimated prey densities (> 80 km-2) in the Park have the potential to support high densities of tigers, we photo-captured only one tigress in the western sector and five adult tigers and two cubs in the east (the latter with a mean density of 5.12 ± SE 0.7 per 100 km2). Whereas recovery of the tiger population in the eastern sector following the resettlement of Gujjars is evident, the lack of connectivity to source populations (Corbett Tiger Reserve and eastern Rajaji National Park) and increased anthropogenic pressures appear to have inhibited the recovery of tiger populations in the western sector. Restoration, therefore, of the Chilla-Motichur corridor to facilitate the dispersal of tigers from the eastern to the western sector of the Park is of critical importance.