Precarious status of the Endangered dhole Cuon alpinus in the high elevation Eastern Himalayan habitats of Khangchendzonga Biosphere Reserve, Sikkim, India

Topcats and underdogs: intraguild interactions among three apex carnivores across Asia's forestscapes

Intraguild interactions among carnivores have long held the fascination of ecologists. Ranging from competition to facilitation and coexistence, these interactions and their complex interplay influence everything from species persistence to ecosystem functioning. Yet, the patterns and pathways of such interactions are far from understood in tropical forest systems, particularly across countries in the Global South. Here, we examined the determinants and consequences of competitive interactions between dholes Cuon alpinus and the two large felids (leopards Panthera pardus and tigers Panthera tigris) with which they most commonly co-occur across Asia. Using a combination of traditional and novel data sources (N = 118), we integrate information from spatial, temporal, and dietary niche dimensions. These three species have faced catastrophic declines in their extent of co-occurrence over the past century; most of their source populations are now confined to Protected Areas. Analysis of dyadic interactions between species pairs showed a clear social hierarchy. Tigers were dominant over dholes, although pack strength in dholes helped ameliorate some of these effects; leopards were subordinate to dholes. Population-level spatio-temporal interactions assessed at 25 locations across Asia did not show a clear pattern of overlap or avoidance between species pairs. Diet-profile assessments indicated that wild ungulate biomass consumption by tigers was highest, while leopards consumed more primate and livestock prey as compared to their co-predators. In terms of prey offtake (ratio of wild prey biomass consumed to biomass available), the three species together harvested 0.4-30.2% of available prey, with the highest offtake recorded from the location where the carnivores reach very high densities. When re-examined in the context of prey availability and offtake, locations with low wild prey availability showed spatial avoidance and temporal overlap among the carnivore pairs, and locations with high wild prey availability showed spatial overlap and temporal segregation. Based on these observations, we make predictions for 40 Protected Areas in India where temporally synchronous estimates of predator and prey densities are available. We expect that low prey availability will lead to higher competition, and in extreme cases, to the complete exclusion of one or more species. In Protected Areas with high prey availability, we expect intraguild coexistence and conspecific competition among carnivores, with spill-over to forest-edge habitats and subsequent prey-switching to livestock. We stress that dhole-leopard-tiger co-occurrence across their range is facilitated through an intricate yet fragile balance between prey availability, and intraguild and conspecific competition. Data gaps and limitations notwithstanding, our study shows how insights from fundamental ecology can be of immense utility for applied aspects like large predator conservation and management of human-carnivore interactions. Our findings also highlight potential avenues for future research on tropical carnivores that can broaden current understanding of intraguild competition in forest systems of Asia and beyond.

Changes in ecological conditions may influence intraguild competition: inferring interaction patterns of snow leopard with co-predators

Background

Large-scale changes in habitat conditions due to human modifications and climate change require management practices to consider how species communities can alter amidst these changes. Understanding species interactions across the gradient of space, anthropogenic pressure, and season provide the opportunity to anticipate possible dynamics in the changing scenarios. We studied the interspecific interactions of carnivore species in a high-altitude ecosystem over seasonal (summer and winter) and resource gradients (livestock grazing) to assess the impact of changing abiotic and biotic settings on coexistence.

Methods

The study was conducted in the Upper Bhagirathi basin, Western Himalaya, India. We analyzed around 4 years of camera trap monitoring data to understand seasonal spatial and temporal interactions of the snow leopard with common leopard and woolly wolf were assessed in the greater and trans-Himalayan habitats, respectively. We used two species occupancy models to assess spatial interactions, and circadian activity patterns were used to assess seasonal temporal overlap amongst carnivores. In addition, we examined scats to understand the commonalities in prey selection.

Results

The result showed that although snow leopard and wolves depend on the same limited prey species and show high temporal overlap, habitat heterogeneity and differential habitat use facilitate co-occurrence between these two predators. Snow leopard and common leopard were spatially independent in the summer. Conversely, the common leopard negatively influences the space use of snow leopard in the winter. Limited prey resources (lack of livestock), restricted space (due to snow cover), and similar activity patterns in winter might result in strong competition, causing these species to avoid each other on a spatial scale. The study showed that in addition to species traits and size, ecological settings also play a significant role in deciding the intensity of competition between large carnivores. Climate change and habitat shifts are predicted to increase the spatial overlap between snow leopard and co-predators in the future. In such scenarios, wolves and snow leopards may coexist in a topographically diverse environment, provided sufficient prey are available. However, shifts in tree line might lead to severe competition between common leopards and snow leopards, which could be detrimental to the latter. Further monitoring of resource use across abiotic and biotic environments may improve our understanding of how changing ecological conditions can affect resource partitioning between snow leopards and predators.

Feeding ecology of the endangered Asiatic wild dogs (Cuon alpinus) across tropical forests of the Central Indian Landscape

Studies on resource utilisation by carnivores are essential as they aid in assessing their role in a community, by unravelling predator–prey relationships. Globally, prey depletion is one of the primary causes of declining Asiatic wild dog (dhole) populations. Therefore, it is essential to examine their diet across their range. Our study presents insights into dhole feeding ecology across multiple sites from the central Indian landscape of Maharashtra, India, for the first time. We conducted scat analysis using a subset of genetically identified scats and collected additional data from kills observed while tracking radio-collared dholes and other known packs from 2 study sites. We analysed 861 scats, and 191 dhole kills to identify species and age class of prey. We estimated the relative contribution of various prey, utilising non-linear biomass models of prey consumption. Overall, wild ungulates like sambar and chital were the principal prey in terms of biomass (sambar 61.08%; chital 19.08%) and number of prey consumed (sambar 39.28%; chital 13.83%). An analysis of kill data also suggested that dholes strongly preferred the two deer species; and differential selection of age classes was observed at the 2 study sites. Our study can potentially help manage and conserve this important population of an endangered carnivore.

Space Use by Woolly Wolf Canis lupus chanco in Gangotri National Park, Western Himalaya, India

The woolly wolf Canis lupus chanco is increasingly being accepted as a unique taxon that needs immediate protection and management; however, information on its ecology remains limited across its range. We used camera trapping data set of 4 years (2015–2019) to investigate seasonal activity patterns and space use and assessed woolly wolf food habits in the Gangotri National Park, western Himalaya, India. We used generalized linear mixed models to assess the distribution of the wolf about prey, seasonal livestock grazing, human presence, habitat, and seasons. We observed a positive association with elevation and a negative response to an increase in ruggedness. The capture of wolves increased in winters, indicating a possible effect of snow on the ranging pattern. Spatial avoidance to anthropogenic pressure was not evident in our study; however, temporal avoidance was observed. The activity pattern of the wolf varied among seasons. Wolves were mostly active in the morning and late evening hours in summer and showed a diurnal activity pattern in winter. A less diverse diet was observed where the mean percentage frequency of occurrence and relative biomass was highest for bharal, followed by livestock. Himalayan marmot Marmota himalayana, birds, and rodents also form minor constituents to the diet. Synthesizing all three factors (space, diet, and activity), it may be stated that the wolf presence in the region is influenced by both wild prey availability and seasonality. Therefore, conservation of woolly wolves would require securing a vast landscape with optimal wild prey.

Mammals of the Bhagirathi basin, Western Himalaya: understanding distribution along spatial gradients of habitats and disturbances

Understanding the distribution of wildlife species and their response to diverse anthropogenic pressures is important for conservation planning and management of wildlife space in human-dominated landscapes. Assessments of anthropogenic impacts on mammals of the Indian Himalayan Region have mostly been limited to locations inside protected areas. We studied the occurrence of mammals in an unexplored landscape, the 7,586 km2 Bhagirathi basin, at an altitude of 500–5,200 m. The basin encompasses wilderness areas of various habitat types and protection status that are exposed to a range of anthropogenic pressures. Camera trapping at 209 locations during October 2015–September 2017 confirmed the occurrence of 39 species of mammals, nine of which are categorized as threatened (four Vulnerable, five Endangered) and four as Near Threatened on the IUCN Red List. We recorded five mammal species that were hitherto undocumented in Uttarakhand State: the argali Ovis ammon, Tibetan sand fox Vulpes ferrilata, woolly hare Lepus oiostolus, Eurasian lynx Lynx lynx and woolly flying squirrel Eupetaurus cinereus. In addition, we recorded two Endangered species, the dhole Cuon alpinus and tiger Panthera tigris. Threatened species such as the sambar Rusa unicolor, common leopard Panthera pardus and Asiatic black bear Ursus thibetanus occur in a wide variety of habitats despite anthropogenic disturbance. We recorded the snow leopard Panthera uncia in areas with high livestock density but temporally segregated from human activities. The musk deer Moschus spp. and Himalayan brown bear Ursus arctos isabellinus were recorded in subalpine habitats and appeared to be less affected by human and livestock presence. Our findings highlight the potential of the Bhagirathi basin as a stronghold for conservation of several threatened and rare mammal species.

Genetic analyses reveal demographic decline and population differentiation in an endangered social carnivore, Asiatic wild dog

Deforestation and agricultural intensification have resulted in an alarming change in the global land cover over the past 300 years, posing a threat to species conservation. Dhole is a monophyletic, social canid and, being an endangered and highly forest-dependent species, is more prone to the loss of favorable habitat in the Anthropocene. We determined the genetic differentiation and demographic history of dhole across the tiger reserves of Maharashtra using the microsatellite data of 305 individuals. Simulation-based analyses revealed a 77-85% decline in the major dhole sub-populations. Protected areas have provided refuge to the historically declining dhole population resulting in clustering with strong genetic structure in the remnant dhole population. The historical population decline coincides with the extreme events in the landscape over the past 300 years. The study highlights the pattern of genetic differentiation and diversity of a highly forest-dependent species which can be associated with the loss of forest cover outside tiger reserves. It also warrants attention to develop conservation plans for the remnant surviving population of dholes in India.

Reappearance of Dhole Cuon alpinus (Mammalia: Carnivora: Canidae) in Gujarat after 70 years

The Dhole Cuon alpinus used to be the meso carnivore of the forests throughout Indian subcontinent; however, habitat loss, low prey biomass, and human disturbance exterminated the species from India’s 60% historic range, and the numbers are less than 1,500 individuals in wild.  Following the same shrinking trend, Dholes were extirpated from Gujarat.  A few doubtful sightings and inevident reportings generated ambiguity of Dhole presence in Gujarat.  We conducted a study in Vansda National Park with 15,660 trap nights at 30 trap locations, and have confirmed the rediscovery of Dholes in Gujarat after 70 years.  We estimated the Dhole’s minimum home range as 13.7km2 and also analyzed relative abundance index of other mammals.  The future retention of Dholes requires detailed range, diet, and adaption studies along with conservational efforts to reduce re-extinction probabilities.

Dhole pack size variation: Assessing the effect of Prey availability and Apex predator

In multipredator systems, group sizes of social carnivores are shaped by the asymmetric intraguild interactions. Subordinate social carnivores experience low recruitment rates as an outcome of predation pressure. In South and Southeast Asia, the Tiger (Panthera tigris), Dhole (Cuon alpinus), and Leopard (Panthera pardus) form a widely distributed sympatric guild of large carnivores, wherein tigers are the apex predators followed by dhole and leopard. In this study, we attempted to understand the variation in pack size of a social carnivore, the dhole, at two neighboring sites in the Central Indian landscape. We further evaluated local-scale patterns of variation in pack size at a larger scale by doing a distribution-wide assessment across the dhole ranging countries. At the local scale, we found an inverse relationship between the density of tiger and pack size of dhole while accounting for variability in resources and habitat heterogeneity. Larger dhole packs (16.8 ± 3.1) were observed at the site where the tiger density was low (0.46/100 km2), whereas a smaller pack size (6.4 ± 1.3) was observed in the site with high tiger density (5.36/100 km2). Our results for the distribution-wide assessment were concordant with local-scale results, showing a negative association of pack size with the tiger densities (effect size -0.77) and a positive association with the prey abundance (effect size 0.64). The study advances our understanding to answer the age-old question of "what drives the pack size of social predators in a multipredator system?" This study also highlights the importance of understanding demographic responses of subordinate predator for varying competitor densities, often helpful in making informed decisions for conservation and management strategies such as population recovery and translocation of species.

Conserving an Endangered Canid: Assessing Distribution, Habitat Protection, and Connectivity for the Dhole (Cuon alpinus) in Bhutan

Most canids face population declines and range contractions worldwide. Although the dhole (Cuon alpinus) is widely distributed across 10 countries in South and Southeast Asia, limited studies exist on this species. Despite its globally “Endangered” status and ecological role as an apex predator, assessments on its distribution are limited to a few landscapes and countries. This explains the lack of a dhole-specific species conservation plan in most range countries, including Bhutan where no current population estimate exists. The species has also recovered from a country-wide poisoning campaign in the 1970s and 80s. In this study, we determine the dhole's distribution pattern and assess the protection and connectivity of dhole habitat in Bhutan. We anticipated dholes to be extant within their habitat well-represented in protected areas (PAs) and biological corridors (BCs). We used 721 georeferenced dhole occurrence records and eight environmental variables in MaxEnt software to model potential dhole distribution and habitat suitability. The model output was overlaid on the spatial layers of PAs and BCs to assess habitat protection and connectivity. As anticipated, we found the dhole widely distributed in all districts, PAs, and BCs in Bhutan. Dholes were recorded at the highest elevation range limit of 4,980 m above sea level, which overlapped with the “Vulnerable” snow leopard (Panthera uncia). Our model identified 72% (27,634 km2) of the country as suitable areas for dholes, of which, 31% (11,899 km2) was highly suitable and 41% (15,735 km2) was moderately suitable. Contrary to our expectation, PAs and BCs encompassed only 29% (8,046 km2) and 12% (3,185 km2) of suitable areas for dholes, respectively. A vast majority of the areas we deemed suitable for dholes currently remain unprotected, thus making dholes more vulnerable to human persecution and local extermination. We recommend adjusting PA boundaries to fully encompass suitable dhole habitat, and also advocate improved livestock husbandry to reduce dhole related livestock predation and minimize conflict, thereby ensuring its long-term survival in Bhutan.

Temporal partitioning by felids, dholes and their potential prey in northern Laos

Temporal partitioning can allow sympatric carnivores to coexist, especially if overlap of other resources is high. Using camera trap data from 2013 to 2017, we investigated the temporal partitioning of a community of wild felids and a canid in Nam Et–Phou Louey National Protected Area, Laos, to determine the extent to which temporal avoidance might be facilitating coexistence of similarly sized carnivores. We also investigated temporal overlap of these carnivore species and their presumed main prey, to determine if their activity is likely most influenced by their prey or potential competitors. The dhole (Cuon alpinus) and clouded leopard (Neofelis nebulosa), the two largest carnivores, had low temporal overlap, and activity appeared to be synchronized with the main prey for dhole, but not clouded leopard. Thus, it was possible that clouded leopard used temporal partitioning to coexist with dhole. The temporal overlap of Asian golden cat (Catopuma temminckii) was high with clouded leopard and moderate with dhole, and overall appeared to be influenced most by its presumed prey species, rather than by its potential competitors. The two small felids had the least temporal overlap between any species, as the marbled cat (Pardofelis marmorata) was primarily diurnal whereas the leopard cat (Prionailurus bengalensis) was primarily nocturnal. Given that the two small felids reportedly have similar diets consisting of small rodents and birds, their temporal partitioning is likely to help facilitate their coexistence. For carnivore species in northern Laos that are most similar in body size and diet, temporal partitioning is likely to be an important mechanism of coexistence. Otherwise, temporal patterns appear to be synchronized with their main prey.

Conservation status of the dhole Cuon alpinus in north-east India, with a focus on Dampa Tiger Reserve, Mizoram

Despite the efforts invested in their conservation, the status of many threatened carnivores in key conservation landscapes remains unknown. The dhole Cuon alpinus is an Endangered social carnivore whose geographical range has contracted by c. 80% since the early 20th century. North-east India is a critical link between South Asian and South-east Asian dhole populations. In this study we compiled presence records of dholes across north-east India, from multiple sources. We also conducted camera-trap surveys in one part of this region, Dampa Tiger Reserve in the state of Mizoram. We examined the influence of ecological and management factors on fine-scale site-use by dholes in Dampa Tiger Reserve, showing a positive association of dhole site-use with sambar Rusa unicolor encounters, distance to the forest boundary and presence of forest department personnel, underscoring the importance of prey and protection. Our findings also highlight the need for targeted, multi-scale assessments of dhole ecology across other sites in north-east India.

Standardization and validation of a panel of cross-species microsatellites to individually identify the Asiatic wild dog (Cuon alpinus)

Background

The Asiatic wild dog or dhole (Cuon alpinus) is a highly elusive, monophyletic, forest dwelling, social canid distributed across south and Southeast Asia. Severe pressures from habitat loss, prey depletion, disease, human persecution and interspecific competition resulted in global population decline in dholes. Despite a declining population trend, detailed information on population size, ecology, demography and genetics is lacking. Generating reliable information at landscape level for dholes is challenging due to their secretive behaviour and monomorphic physical features. Recent advances in non-invasive DNA-based tools can be used to monitor populations and individuals across large landscapes. In this paper, we describe standardization and validation of faecal DNA-based methods for individual identification of dholes. We tested this method on 249 field-collected dhole faeces from five protected areas of the central Indian landscape in the state of Maharashtra, India.

Results

We tested a total of 18 cross-species markers and developed a panel of 12 markers for unambiguous individual identification of dholes. This marker panel identified 101 unique individuals from faecal samples collected across our pilot field study area. These loci showed varied level of amplification success (57–88%), polymorphism (3–9 alleles), heterozygosity (0.23–0.63) and produced a cumulative misidentification rate or PID_(unbiased) and PID_(sibs) value of 4.7 × 10⁻¹⁰ and 1.5 × 10⁻⁴, respectively, indicating a high statistical power in individual discrimination from poor quality samples.

Conclusion

Our results demonstrated that the selected panel of 12 microsatellite loci can conclusively identify dholes from poor quality, non-invasive biological samples and help in exploring various population parameters. This genetic approach would be useful in dhole population estimation across its range and will help in assessing population trends and other genetic parameters for this elusive, social carnivore.

Recent records of dhole (Cuon alpinus, Pallas 1811) in Uttarakhand, Western Himalaya, India

Camera trap photographs of solitary individuals of Asiatic wild dog or dholes (Cuon alpinus, Pallas 1811) have been recorded from Kheda Tal area in Uttarkashi district of Uttarakhand. This is the first photographic confirmation of the presence of this species in the Himalayan habitats of Uttarakhand. The presence of dholes here seems to be confined to a relatively small area of unprotected habitats affected by various anthropogenic uses. The population of endangered dhole is rapidly declining especially in Himalayan region. Thus, it is imperative that local stakeholders are aware of their presence, and it is highly recommended that investigations of the ecological parameters of this population are continued.