Monday 13 January 2020

Cuon alpinus: Understanding the distribution of Dholes in northeast India.

The Dhole, or Asian Wild Dog, Cuon alpinus, is an Endangered social carnivore found in forested landscapes of South and Southeast Asia. Historically widespread across Asia, the species’ range has contracted by about 80%. The current distribution extends across most of South and Southeast Asia and parts of China but is largely restricted to protected areas. The protected forest landscapes south of the River Ganges in India are a stronghold for the species, with the largest Dhole population. However, the species has undergone local extirpation across parts of its former range as a result of declines of prey species, loss of habitat and, potentially, disease. Information on Dholes in northeast India in particular is limited, despite the fact that this landscape shares continuous forest with Myanmar and Southeast Asia, forming an important part of the species' global range.

A Dhole, or Asian Wild Dog, Cuon alpinus. David Raju/Wikimedia Commons.

In a paper published in the journal Orynx on 23 October 2019, Priya Singh of Researchers for Wildlife Conservation at the National Centre for Biological Sciences, and the School of Natural Resources and Environment at the University of Florida, Arjun Srivastha of the Department of Wildlife Ecology and Conservation at the University of Florida, and David Macdonald of the Wildlife Conservation Research Unit at the University of Oxford, provide a compilation of dhole presence records from across northeast India using data extracted from multiple sources.

Current knowledge of Dholes in north-east India is restricted to landscapes north of the River Brahmaputra. This is primarily because of the paucity of baseline ecological data from the region, given its undulating terrain, difficulty of access, wet climatic conditions, and socio-political insurgencies.

Using data from camera-trap surveys Singh et al. examine factors influencing fine-scale site-use by Dholes in Dampa Tiger Reserve in Mizoram State. They discuss the implications of their results for Dhole conservation in northeast India, where the focus of wildlife managers is directed mainly towards population recoveries of and local recolonisation by the Tiger, Panthera tigris. They further provide recommendations for management interventions that could facilitate conservation of Dholes in this hitherto neglected landscape.

Dampa Tiger Reserve lies in the Indo-Myanmar Biodiversity Hotspot. The reserve is contiguous with the Chittagong Hill Tract region of Bangladesh to the west. The core area of the Reserve covers 500 km², and the multi-use buffer covers an area of 488 km². The Lushai Hills traverse the reserve, with altitudes of 250-1100 m. Mean annual rainfall is 2000-2500 mm. The Reserve supports a high diversity of Carnivores, including, in addition to the Dhole, four species of Felids and two species of Ursids. In the course of the study Singh et al. also recorded the Elephant, Elephas maximus, Gaur, Bos gaurus, Sambar, Rusa unicolor, Red Serow, Capricornis rubidus, Muntjac, Muntiacus muntjak, and Wild Pig, Sus scrofa.

Northeast India, with the Dampa Tiger Reserve in Mizoram and locations where the Dhole, Cuon alpinus, has been recorded, with corresponding reliability scores. Singh et al. (2019).

Singh et al. compiled Dhole presence records for nine northeastern states: Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim, Tripura, and West Bengal. They searched for records from 1990 onwards in newspaper reports, scientific articles, grey literature (including species checklists), and reports by Forest Department personnel, local informants and naturalists working in the region. For each record they noted the type of evidence (direct/indirect), the date of the sighting, the administrative status of location (protected/non-protected), and the source person or reference. They assigned reliability scores for each record, from 1 to 5, with 1 being most reliable, and 5 least reliable.

From December 2014 to March 2015, Singh et al. deployed 79 pairs of Cuddeback Ambush IR camera traps across 80 km² in the northeast of Dampa Tiger Reserve’s core area. At each station they placed two cameras facing each other, about 30 cm above the ground, on either side of forest trails or on riverbeds. Mean inter-trap distance was 1.02 km, with traps remaining active for an average of 64 days. Although the stations were intended to photograph wild Felids, they also photographed other Carnivores. Dholes generally use forest trails and riverbeds for movement, marking territories and hunting, and our sampling design therefore incorporated areas used by the species.

Singh et al. obtained presence records from 80 locations for 1990-2018, of which we considered 41 records from 2010–2018 with reliability scores of 1-3. In the case of multiple records for the same site, they considered the most recent record with the highest reliability score. Most records were from Arunachal Pradesh (14) and Assam (8), with five records from Mizoram and Nagaland, four from West Bengal, three from Meghalaya and two from Sikkim. There were no recent records of Dholes from Manipur and Tripura. A total of 5033 camera trap-days in Dampa Tiger Reserve generated 500 photoencounters of Dholes, comprising 92 detections (one per 24 hour duration) across 33 sites. 

Singh et al. found photo-capture frequencies of key prey species: Sambar (236), Muntjac (145), Wild Pig (92); to be positive influences, as were the distance to reserve boundary, and photo-capture frequencies of Forest Department personnel, while photo-capture frequencies of other humans were  negative influences on site-use by Dholes.

There are records of Dholes across several areas of northeast India, including in unprotected areas. Previous global assessments indicated that the species faced near or complete local extirpation to the south of the River Brahmaputra, something refuted by Sigh et al.'s findings from Dampa Tiger Reserve. Corroborating current knowledge from other landscapes, showed a positive relationship between Dhole site-use and Sambar presence. Across their extant distribution, the range of Dholes overlaps with that of Tigers and Leopards, Panthera pardus. Wildlife managers in this region and elsewhere subscribe to unsubstantiated notions that dhole presence impedes colonisation by Tigers, and consequently treat Dholes as a problem species. On the contrary, Tigers, Leopards and Dholes can co-exist provided protected areas support adequate densities of medium- to large-sized prey species.

Dampa Tiger Reserve is an important refuge for Dholes in northeast India. It supports large tracts of inviolate protected spaces, and habitat connectivity with forested landscapes of the Chittagong Hill Tract region to the west, Mamit Forest Division to the north and Thorangtlang Wildlife Sanctuary to the south. Singh et al's camera-trap data indicate the presence of a guild of large herbivores in the Reserve, with at least five prey species of medium and large ungulate herbivores, facilitating the long-term persistence of dholes there. The findings re-emphasise the importance of protected areas, which can serve as source sites for sustaining Dhole populations across the region.

In areas with low prey densities, carnivores may have significant dependence on livestock, and are consequently stigmatised. There is a strong negative relationship between Dholes and livestock owners in Arunachal Pradesh and other locations in the region. Given that Dholes also occur outside protected areas in this region, they are potentially vulnerable to retributory killing. Negative interactions between people and Dholes necessitate interventions to reduce poaching and facilitate recovery of prey, especially for species such as Sambar that are impacted by low recovery rates following prolonged poaching. Singh et al.'s findings need to be augmented with a systematic survey across the locations they identified, specifically in the states of Mizoram and Nagaland, to facilitate a pan-northeast India strategy for Dhole conservation.

See also...

https://sciencythoughts.blogspot.com/2019/08/leopard-attack-thwarted-by-dog-in.htmlhttps://sciencythoughts.blogspot.com/2019/08/camper-attacked-by-wolf-in-banff.html
https://sciencythoughts.blogspot.com/2018/07/worker-at-western-australian-gold-mine.htmlhttps://sciencythoughts.blogspot.com/2016/08/cynarctus-wangi-new-species-of.html
https://sciencythoughts.blogspot.com/2016/07/photogrammetry-as-tool-in-morphometric.htmlhttps://sciencythoughts.blogspot.com/2016/04/lycaon-pictus-african-hunting-dogs.html
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