Tiger Landscape Research Articles

Insufficient numbers and poor working conditions for rangers protecting tigers

AbstractProtected area rangers are planetary health care workers and are at the frontline of the protection of wildlife and wild places. Ensuring that there are sufficient rangers in protected areas, and that these rangers are equipped and provided with decent working conditions, is critical to protecting iconic species such as tiger Panthera tigris. Using data from a global survey of public‐sector ranger numbers, we estimate the shortfall in the number of rangers required to safeguard protected areas in Tiger Conservation Landscapes (TCLs) across the 10 Asian countries with breeding tigers. We calculate the cost required to address this shortfall in ranger numbers. We also estimate the costs for meeting a subset of the welfare needs of rangers aligned to the Chitwan Declaration of the World Ranger Congress. We estimate that a minimum of 12,500 more rangers are required across ~320,000 km2 of tiger‐bearing protected areas. We estimate this would cost US$ 45.8 million annually. The majority (63%) of these rangers are required in three Southeast Asian countries, which have declining tiger numbers. To meet a subset of the basic welfare needs of rangers, we estimate that an additional US$ 7.8 million is required annually across the 10 countries. While the funding gap that we estimate excludes many aspects of effective protected area management, we provide further evidence that protected areas in the biodiverse tropics remain underfunded. Increasing funding for rangers is a critical component of what is required to protect the tiger and tiger landscapes. We urge tiger range country governments, and the global conservation community, to secure this funding. Increasing the numbers of rangers, and effectively supporting their welfare, will increase our ability to protect the tiger and the ecologically significant landscapes in which it occurs.

Putting ducks in a row: Village resettlement prioritization from inside tiger reserves and its implication in achieving global conservation goals for India

Following the local extermination of tigers from India’s two premier reserves, village relocation as a policy to create more inviolate space for tiger breeding was conceived by the Indian Government a decade ago. However, given the significant number of human settlements inside tiger reserves, it is neither feasible nor realistic to consider all villages for relocation. There is an urgent need to prioritise villages for relocation to maximise conservation benefits. Here, we developed a framework for prioritizing village relocation by setting national, landscape and site-specific goals. We have identified ten source sites in Central India and Western Ghats tiger landscapes for immediate attention for conservation-related resettlements. Our study shows that village resettlement prioritization provides an optimum level of conservation success at a much-reduced budget. The scenario will help increase tiger numbers and reduce conflict by increasing inviolate space at site, landscape, and national levels. This approach will help India achieve global conservation targets for tigers with minimum conflict.

Mitigating human-wildlife conflict and monitoring endangered tigers using a real-time camera-based alert system.

The recovery of wild tigers in India and Nepal is a remarkable conservation achievement, but it sets the stage for increased human-wildlife conflict where parks are limited in size and where tigers reside outside reserves. We deployed an innovative technology, the TrailGuard AI camera-alert system, which runs on-the-edge artificial intelligence algorithms to detect tigers and poachers and transmit real-time images to designated authorities responsible for managing prominent tiger landscapes in India. We successfully captured and transmitted the first images of tigers using cameras with embedded AI and detected poachers. Notifications of tiger images were received in real time, approximately 30 seconds from camera trigger to appearing in a smart phone app. We review use cases of this AI-based real-time alert system for managers and local communities and suggest how the system could help monitor tigers and other endangered species, detect poaching, and provide early warnings for human-wildlife conflict.

Prey selection by the Indian tiger (Panthera tigris tigris) outside protected areas in Indias Western Ghats: implications for conservation

As habitat loss and fragmentation increase globally, biodiversity conservation approaches are increasingly being implemented at the landscape scale to maintain metapopulations of endangered species. The present study investigated the food habits of tiger Panthera tigris in the less protected reserve forests of Begur Range, a wildlife corridor in the Malenad–Mysore Tiger Landscape (MMTL) in India's Western Ghats. Fifty scat samples were collected and analyzed to determine the diet composition. The study recorded seven tiger prey species from the study area. The percentage composition of different prey species revealed that chital (Axis axis) constitutes 63.15% of the overall diet, whereas sambar (Rusa unicolor) and gaur (Bos gaurus) constituted 26.33% each. Contrary to our prediction, the relative biomass of different prey species showed that chital, sambar, and gaur constituted 95% of the overall diet. The presence of small prey species such as the Indian crested porcupine (Hystrix india) and small Indian civet (Viverricula indica) indicates opportunistic hunting behaviour and diverse prey selection by tigers. This study highlights the significance of areas outside the protected area network for conserving large carnivores and ecosystem processes associated with them in the Western Ghats global biodiversity hotspot.

Assessing tiger corridor functionality with landscape genetics and modelling across Terai-Arc landscape, India

India led the global tiger conservation initiatives and has doubled its wild tiger population to 2967 (2603–3346) since 2006. As the extant habitats are shrinking continuously, the persistence of these growing populations can only be ensured through focused landscape-scale conservation planning across all the existing tiger landscapes of Indian. We used intensive field-sampling, genetic analyses and GIS modelling to investigate tiger population structure, source-recipient dynamics and functionality of the existing corridors across the Indian part of Terai-Arc landscape (TAL). Using a 13 microsatellite marker panel we identified 219 individual tigers across Indian TAL. Further genetic analyses revealed three weakly, but significantly differentiated tiger subpopulations, termed as ‘Tiger Genetic Blocks (TGBs)’. Genetic migrant detection and gene flow analyses distinguished seven source and 10 recipient areas within this landscape. Circuitscape analyses ascertained total 19 (10 high, three medium and six low conductance) corridors across this landscape, of which 10 require immediate conservation attention. Overall, the tiger populations residing in the western, central and eastern TAL still maintain functional connectivity through these corridors. We suggest urgent management plan involving habitat recovery and protection of ~ 2700 sq. km. identified area to establish landscape connectivity. Further, mitigation measures associated with ongoing linear infrastructure developments and transboundary coordination with Nepal will ensure habitat and genetic connectivity and long-term sustainability of tigers in this globally important landscape.

Crossing structure use in a tiger landscape, and implications for multi-species mitigation

Crossing structures (CS) for wildlife are important mitigation strategies to offset impacts of roads on wildlife. However, information on CS use for the Indian subcontinent or the global tiger landscapes is scarce. We monitored wildlife use of nine CS on a national highway in a critical tiger conservation landscape in India. 21 wild mammals were found to use the CS within a span of 2 years. Tigers, wild dogs, most small mammals and ungulates were found to use CS that were near protected area, while ungulates and small mammals preferred CS with proximal vegetation cover. High species richness was observed under large CS. Similar capture rates for large carnivores between CS and adjacent habitat were observed. We found varied responses by structure generalists and specialists, a consequence of animal behavior and tolerance to human disturbance. We posit that animal behavior holds the key to designing and managing effective wildlife CS.

Relocated tigers and relocated villagers: Ferality and human–animal entanglement in Indian conservation

AbstractThis article will examine state intervention in the lives of tigers and people living in and around Panna Tiger Reserve in Madhya Pradesh, Central India. It explores how, over a decade after a reintroduction project rebuilt the tiger population from extinction and the central government launched a new compensation scheme to relocate villagers away from the national park, relocated tigers and not-yet relocated villagers resist and challenge conservation interventions to eradicate human life in Panna Tiger Reserve and (re)construct it as a wild tiger landscape. It will show how discourses of conservation and development that motivate state intervention seek to depoliticize and obfuscate programmes of control over human and tiger lives through their separation and purported ‘care’, contiguous with colonial policies and discursive practices that have intertwined the fate of wild animals and forest-dependent villagers in this part of India. In their feral subversions against these interventions, relocated tigers and not-yet relocated villagers expose the problematic contradictions and tensions that plague animal management, wildlife conservation, and rural development in India today. Based on 15 months of ethnographic fieldwork, the article draws on case studies and accounts from communities living around Panna Tiger Reserve to present alternatives to colonial and post-colonial discursive legitimizations of state intervention and control, revealing alternate understandings of the entanglement of humans and animals and the categories of ‘wild’ and ‘tame’.

Conservation Prioritization in a Tiger Landscape: Is Umbrella Species Enough?

Conservation approaches in tiger landscapes have focused on single species and their habitat. Further, the limited extent of the existing protected area network in India lacks representativeness, habitat connectivity, and integration in the larger landscape. Our objective was to identify sites important for connected tiger habitat and biodiversity potential in the Greater Panna Landscape, central India. Further, we aimed to set targets at the landscape level for conservation and prioritize these sites within each district in the landscape as specific management/conservation zones. We used earth observation data to derive an index of biodiversity potential. Marxan was used to identify sites that met tiger and biodiversity conservation targets with minimum costs. We found that to protect 50% of the tiger habitat with connectivity, 20% of the landscape area must be conserved. To conserve 100% of high biodiversity potential, 50% moderate biodiversity potential, and 25% low biodiversity potential, 55% of the landscape area must be conserved. To represent both tiger habitat and biodiversity, 62% of the total landscape area requires conservation or restoration intervention. The prioritized zones can prove significant for hierarchical decision making, involving multiple stakeholders in the landscape, including other tiger range areas.

Collection and Distribution of Mahua (<I>Madhuca longifolia</I>), Tendu (<I>Diospyros melanoxylon</I>) and other NTFP's in Critical Tiger Connectivity Corridor of Maharashtra

Vidarbha Tiger Landscape in Maharashtra is an important Tiger Panthera tigris tigris connectivity linkage between Central India Tiger Conservation Landscape. The Nagzira Nawegaon Brahmapuri landscape acts as sinks for the Tiger source populations between Tadoba, Pench and Kanha Tiger Reserves from North to South and Vice Versa. These corridors are inhabited with several villages, dependent on the forest resources for subsistence and supplementary income. The major source of supplementary income post agriculture period for villages are collection of Tendu ( Diospyros melanoxylon ), Mahua ( Madhuca longifolia ) and other Non-Timber Forest Produces, also the trigger points for human wildlife conflict. Several programmes on reducing dependence on forest resources are implemented in these connectivity corridors by government agencies and Non-Government Organizations. This study from Vidarbha Landscape, first time documents collection and distribution of two of the most collected and other selective NTFP tree species in village common and agriculture areas, between the two Tiger connectivity corridors; Nagzira Nawegaon Tiger Reserve and Brahmapuri Forest Division near Tadoba Andhari Tiger Reserve in Maharashtra. The findings of study indicate marginal landholders and landless more dependent on collection of these resources. The findings of the study contribute towards developing inclusive corridor and conflict management plan for both the regions.

Habitat use by tiger prey in Thailand’s Western Forest Complex: What will it take to fill a half-full tiger landscape?

Tiger populations are declining globally, and depletion of major ungulate prey is an important contributing factor. To better understand factors affecting prey distribution in Thailand’s Western Forest Complex (WEFCOM), we conducted sign surveys for gaur (Bos gaurus), banteng (Bos javanicus), and sambar (Rusa unicolor) along 3517 1-km transects and used occupancy models to identify important covariates associated with habitat use by each species. Habitat use by both gaur and sambar was lowest in areas closest to human settlements, although sambar preferred lower slopes near streams whereas gaur preferred steeper slopes at higher elevations. Banteng were found in only one of 17 protected areas (Huai Kha Khaeng [HKK] Wildlife Sanctuary), where they used low elevations and low slopes. We used these modeled relationships to predict occurrence of gaur, sambar, and banteng across each square km of the 19,000 km2 WEFCOM landscape, using > 60 % occupancy probability to define suitable habitat use for each species. Based on this criterion, gaur and sambar occupied 28 and 50 % of suitable habitat in WEFCOM, and banteng occupied 57 % of suitable habitat in HKK. We used our models to assess the effectiveness of two hypothetical conservation initiatives. First, we modeled the impact of decreasing human activities around nine villages in the core of WEFCOM, which increased predicted suitable habitat in WEFCOM to 68 and 75 % for guar and sambar. We also modeled the extent of potential banteng habitat that still remains in the other 16 protected areas. This could result in a 4-fold increase in banteng suitable habitat in WEFCOM. This is the first study to use occupancy surveys to determine where large prey species can be restored to support management to increase the distribution of tigers, and potentially fill a half-full tiger landscape.

Spatial differences in prey preference by tigers across the Bangladesh Sundarbans reveal a need for customised strategies to protect prey populations

The Sundarbans is the only mangrove habitat in the world to support tigers Panthera tigris, whose persistence there is believed to be dependent on a very limited number of prey species. Conservation managers therefore need to understand how tigers utilise available prey species on a spatial scale in order to formulate a prey-based protection strategy for this global-priority tiger landscape. A total of 512 scat samples were collected during a survey of 1984 km2 of forest across 4 sample blocks in the 6017 km2 of the Bangladesh Sundarbans. Analysis of scat composition and prey remains reliably identified 5 major prey species, of which spotted deer Axis axis and wild pig Sus scrofa contributed a cumulative biomass of 89% to tiger diet. Tiger preference for prey species was highly skewed towards spotted deer and wild pig, but the relative contribution of these 2 species differed significantly across the 4 study areas, which spanned the Sundarbans, demonstrating important spatial patterns of tiger prey preference across the Sundarbans landscape. Given the comparatively limited number of prey species available to support the dwindling tiger population, different strategies are needed in different parts of the Sundarbans to support tiger populations and to protect spotted deer and wild pig populations from unabated poaching.

Mapping of Physical Vulnerability in Tiger Habitat Areas: A Case Study of Tiger Corridor of Rajasthan, India

Abstract. Nowadays, biodiversity is very rapidly diminishing from all over the globe due to unsustainable practices of natural resource by anthropogenic activities. It is an unhealthy for ecosystem services. In the biodiversity, tiger is an icon of healthy wildlife, which is known as a vital factor for maintaining universal food chain system. The research paper is focused on “Mapping of Physical Vulnerability of Tiger Habitat Areas: A Case Study of Tiger corridor of Rajasthan, India” it’s a micro level Study based on primary and secondary data through GIS mapping, habitat ranking and Q-Q plot. All five physical factors to inter-connect and overlay of the ranking of tiger habitats for the physical vulnerability. Especially, core and periphery of vulnerability have obtained from the Multispectral images from ETM and ETM+ sensors of Landsat and LISS-III and AWiFS sensors of Resourcesat-satellites. The study examines the spatial pattern physical vulnerability and suitability of tiger corridor of Rajasthan. Tiger Landscape change within all ecological zones has been evaluated. The Landsat TM and ETM imagery has been used to produce LULC classification maps for both areas utilising a hybrid supervised/unsupervised methods. LULC changes are measured using landscape metrics and change maps created by post-classification through change detection. Using all the raster maps and the final change detection of the reserve has been done through spatial analysis using the raster calculator tool in ArcGIS, Erdas, Statistical tool and MS Excel 13. The study comes out with physical vulnerability in core and periphery areas of the tiger corridor. The research addressed vulnerability of tiger habitat, human encroachment, impact on tiger habitat, intervene of domestic animals, and the migration in core and periphery areas, finally, the situation of physical vulnerability would be alarming for biodiversity of tiger corridor, specially buffer areas.

Demography of a high‐density tiger population and its implications for tiger recovery

Abstract Prioritizing conservation of source populations within landscapes is proposed as a strategy for recovering tigers globally. We studied population dynamics of tigers in Corbett National Park (CNP) in Indian Terai, which harbours the largest and highest density tiger population in any protected area of the world. Through population viability models, we demonstrate the importance of CNP in tiger recovery within western Terai. We camera trapped 521 km2 of CNP using open population capture–mark–recapture framework between 2010 and 2015 to estimate annual abundance, spatially explicit density, survival, recruitment, temporary movements, sex ratio and proportion of females breeding. We model metapopulation persistence with and without Corbett as a source within western Terai landscape at different levels of poaching and habitat connectivity. In 6 years, we recorded 6,202 photo‐captures of 307 individual tigers. Annual tiger abundance and density were stable at 120 (SE 19) and 14 (SE 3) per 100 km2 respectively. Detection probability of tigers was 0.18 (SE 0.03) and detection‐corrected male:female sex ratio was female biased (0.80 SE 0.13). Apparent annual survival probability was 0.79 (SE 0.05) for females and 0.60 (SE 0.04) for males. Survival of tigers in CNP (0.68 SE 0.12) was lower than that reported for other populations. CNP tigers showed high reproduction with 54.8 (SE 5.1)% females breeding and with addition of 35 (SE 8)% as new recruits to the population each year. Small tiger populations in western Terai with moderate poaching could only persist through dispersal from CNP. Synthesis and applications. Corbett tiger population was characterized by a stable high density, high reproductive rate and low survival, resulting in high turnover rates (32%–48%) between successive years. Such source populations could sustain low‐level poaching and with habitat connectivity, recover tiger populations across the landscape. This study establishes potential thresholds that can likely be achieved by tiger populations under optimal natural conditions and highlights the importance of prioritizing conservation of source populations within tiger landscapes. This information can be used to plan and implement realistic tiger recovery programmes globally.

Future governance options for large-scale land acquisition in Cambodia: Impacts on tree cover and tiger landscapes

This paper investigates how large-scale land acquisitions (LSLAs) can be governed to avoid underuse and thereby spare room for other land claims, specifically nature conservation. LSLA underuse occurs when land in LSLAs is not converted to its intended use. Taking Cambodia as a case, we map converted and unconverted areas within LSLAs using remote sensing. We develop three scenarios of alternative LSLA policies until 2040, and use a land system change model to evaluate how governing the underuse of LSLAs affects overall land use. Specifically, we evaluate the impact of these policies on future tree cover, the size and spatial integrity of natural areas, and the potential these natural areas can offer to meet the conservation target of a successful tiger reintroduction. In 2015, only 32% of LSLA area was converted. Simulations suggest that both interventionist (reclaim unconverted areas) and preventive (avoid non-conversion) policies dramatically reduce underuse. Interventionist policies perform best in limiting tree cover loss and in preserving natural areas, but preventive measures lead to significantly less fragmentation. Noninterventionist policies (no enforced policies) make tiger reintroduction in the Eastern Plains impossible. Preventive policies with well-enforced protected areas succeed in creating the largest potential for tiger reintroduction. Our results suggest that Cambodia can reconcile LSLAs with tiger reintroduction in the Eastern Plains only when using preventive land use policies. In the absence of such policies, tiger survival in the Eastern Plains is unlikely and only the Cardamom or Virachey forest may offer such potential.

Noninvasive DNA-based species and sex identification of Asiatic wild dog ( $${\varvec{Cuon~alpinus}}$$ C u o n a l p i n u s )

Asiatic wild dog (Cuon alpinus) or dhole is an endangered canid with fragmented distribution in South, East and Southeast Asia. The remaining populations of this species face severe conservation challenges from anthropogenic interventions, but only limited information is available at population and demography levels. Here, we describe the novel molecular approaches for unambiguous species and sex identification from noninvasively collected dhole samples. We successfully tested these assays on 130 field-collected dhole faecal samples from the Vidarbha part of central Indian tiger landscape that resulted in 97 and 77% successrates in species and sex identification, respectively. These accurate, fast and cheap molecular approaches prove the efficacy of such methods in gathering ecological data from this elusive, endangered canid and show their application in generating population level information from noninvasive samples.

Mapping and predicting forest loss in a Sumatran tiger landscape from 2002 to 2050

Riau Province in central Sumatra, with its peatland, lowland, and montane forest habitats, was once a stronghold for Sumatran tiger (Panthera tigris sumatrae) populations. Today, Riau may have one of the highest deforestation rates in the world and wildlife populations are dwindling, with natural forest now comprising approximately only 18% of the province, mostly contained within protected areas. Agriculture (acacia, rubber, and oil palm) makes up the majority of Riau's land cover and deforestation for the creation of new plantations is rampant. Natural forest and tigers still remain in Bukit Tigapuluh National Park and Rimbang Baling Wildlife Reserve, which remain connected to tiger populations in montane forest on the western edge of Sumatra. In this study, using freely available Landsat imagery and a maximum likelihood classification algorithm, we create land cover maps for central Sumatra from 2002 to 2016. We then use current land cover, elevation, and slope variables to predict changes from forest to plantation from 2016 to 2050 at five year intervals using a multilayer perceptron neural network. Finally, we compare connectivity based on a 100 km distance threshold (based on potential tiger dispersal) across the landscape and across years. Land cover maps had 80–90% accuracy, and we predict forest in Tesso Nilo and the western edge of the study area to be lost by 2050 given current rates of deforestation. Our connectivity analysis shows that Tesso Nilo and the area between Rimbang Baling and Bukit Tigapuluh are important components for maintaining connectivity throughout the study area. Focusing conservation and rehabilitation efforts on forests close to plantations in flat areas, including Tesso Nilo, is necessary to maintain forests and increase connectivity in Riau to ensure future habitat connectivity for survival of tigers and Sumatra's other diverse endemic species.

Targeting restoration sites to improve connectivity in a tiger conservation landscape in India.

BackgroundMaintaining and restoring connectivity between source populations is essential for the long term viability of wide-ranging species, many of which occur in landscapes that are under pressure to meet increasing infrastructure needs. Identifying barriers in corridors can help inform conservation and infrastructure development agencies so that development objectives can be achieved without compromising conservation goals. Here, we use the tiger landscape in central India as a case study to identify barriers, associate them with existing infrastructure, and quantify the potential improvement by restoring or mitigating barriers. Additionally, we propose an approach to categorize linkages based on their current status within and between Protected Areas (PAs).MethodsWe generated a hybrid landuse-landcover map of our study area by merging datasets. We used least-cost methods and circuit theory to map corridors and generate linkage metrics. We mapped barriers and used the improvement score (IS) metric to quantify potential improvement by restoring or mitigating them. Based on criteria that represent the status of corridors between-PAs and populations within-PAs, we ranked linkages into one of four categories: Cat1—linkages that currently have high quality and potential for tiger connectivity and should be maintained, Cat2W—linkages where focus on habitat and tiger populations may improve connectivity, Cat2B—linkages where focus on reducing barriers between PAs may improve connectivity, and Cat3—linkages where effort is needed to both reduce barriers between PAs and improve tiger populations and habitat within PAs. We associated barriers with infrastructure and present maps to show where restoration or mitigation measures can be targeted to have the highest potential impact.ResultsWe mapped 567 barriers within 30 linkages in this landscape, of which 265 barriers intersect with infrastructure (694 km of roads, 150 km of railway, 48 reservoirs, 10 mines) and 302 barriers are due to land-use or gaps in forest cover. Eighty-six barriers have both roads and railways. We identified 7 Cat1, 4 Cat2w, 9 Cat2b, and 10 Cat3 linkages. Eighty surface mines and thermal power plants are within 10 km of the least-cost paths, and more coal mines are closer to connectivity areas where linkages are narrow and rank poorly on both axes.DiscussionWe present spatial and quantitative results that can help conservation practitioners target mitigation and restoration efforts. India is on the path to rapid economic growth, with infrastructure development planned in biodiversity-rich areas. The mitigation hierarchy of avoiding, minimizing, and offsetting impacts due to proposed development projects can be applied to corridors in this landscape. Cross-sectoral cooperation at early stages of project life-cycles to site, design, and implement solutions can maintain connectivity while meeting infrastructure needs in this rapidly changing landscape.

Geo-Spatial Mapping of Land Use and Land Cover Changes in the Core and Periphery Area of Ranthambore Tiger Reserve, Rajasthan, India, 1975–2015

Abstract In the near future, natural resources are very rapidly diminishing all over the globe. Which is very unhealthy for land ecosystem services. In the biodiversity, Tiger is an icon of healthy wildlife which is considered as a vital factor for maintaining Universal Food Chain System. This research paper is based on “Geo-Spatial Mapping of land use and land cover changes in the Core and Periphery Area of Ranthambore Tiger Reserve, Rajasthan, India, 1975-2015, it’s a micro level Study based on primary and secondary data through GIS mapping and consider as a Socio-Economic & Physical factors to inter-connect with Tiger habitats. Especially, core and periphery LULC have been obtained from the Multispectral images from ETM and ETM+ sensors of Landsat and LISS-III and AWiFS sensors of Resourcesat-satellites. This study examines the spatial and temporal patterns of LULC change along the boundary of Ranthambhore in the Rajasthan from 1975 to 2015. Tiger Landscape change within all ecological zones will be evaluated. The Landsat TM and ETM imagery will be used to produce LULC classification maps for both areas using a hybrid supervised/unsupervised methods. LULC changes are measured using landscape metrics and change maps created by post-classification through change detection. Using all the raster maps and the final change detection of the reserve will be done through spatial analysis using the raster calculator tool in ArcGIS and Erdas and MS Excel 13. The study comes out with land use and land cover change in core and periphery areas of the reserve. The research also describes Human Encroachment, Impact on human colonization, interfere with domestic animals, Interbreeding, and the Migration in core and periphery areas, finally, the situation would be alarming for biodiversity of tiger habitat due to the high pressure of anthropogenic activities.

Evaluating a Survey Landscape for Tiger Abundance in the Confluence of the Western and Eastern Ghats

Due to the current depleting trends in tiger population, range countries have committed to double tiger numbers by the year 2022. However, some areas, including source sites, across the range countries lack scientifically estimated tiger numbers both at the larger landscape and at the protected area level. Here we report a population of tigers, from Biligiri Rangaswamy Temple Tiger Reserve (BRTTR), using camera trap based capture-mark recapture in a spatially explicit likelihood and Bayesian analyses that yielded an estimate of ~55 tigers with a density of about 6.8 tigers/100 km 2 . BRTTR nestled in a larger tiger landscape, perhaps contributes dispersing individuals to the adjoining forests, calling for integrated monitoring and management efforts for the entire landscape. This data set could help in designing long-term, landscape level plans and outcomes.

Using non-invasively collected genetic data to estimate density and population size of tigers in the Bangladesh Sundarbans

Population density is a key parameter to monitor endangered carnivores in the wild. The photographic capture-recapture method has been widely used for decades to monitor tigers, Panthera tigris, however the application of this method in the Sundarbans tiger landscape is challenging due to logistical difficulties. Therefore, we carried out molecular analyses of DNA contained in non-invasively collected genetic samples to assess the tiger population in the Bangladesh Sundarbans within a spatially explicit capture-recapture (SECR) framework. By surveying four representative sample areas totalling 1994 km2 of the Bangladesh Sundarbans, we collected 440 suspected tiger scat and hair samples. Genetic screening of these samples provided 233 authenticated tiger samples, which we attempted to amplify at 10 highly polymorphic microsatellite loci. Of these, 105 samples were successfully amplified, representing 45 unique genotype profiles. The capture-recapture analyses of these unique genotypes within the SECR model provided a density estimate of 2.85 ± SE 0.44 tigers/100 km2 (95% CI: 1.99–3.71 tigers/100 km2) for the area sampled, and an estimate of 121 tigers (95% CI: 84–158 tigers) for the total area of the Bangladesh Sundarbans. We demonstrate that this non-invasive genetic surveillance can be an additional approach for monitoring tiger populations in a landscape where camera-trapping is challenging.