- Swamp deer, a rare and threatened species, have disappeared from Chitwan National Park after a failed translocation attempt.
- A new study maps the potential habitat of swamp deer in Nepal’s western Terai and suggests ways to conserve and restore the habitat.
- Researchers and officials stress the need for improving connectivity between habitats in Nepal and India and creating a second population of swamp deer in Chitwan.
KATHMANDU, Nepal — In June 2021, officials at Nepal’s Chitwan National Park said that an animal had been missing for five months. The missing animal was no ordinary one; it was a rare deer translocated from its home hundreds of kilometers away.
The missing swamp deer (Rucervus duvaucelii), also known as barashinghe (or barsingha) for its fabled 12-point antlers (which can even exceed 12), was the last member of a herd translocated from Shuklaphanta National Park in western Nepal, which, together with neighboring Bardiya National Park, is the last remaining habitat of the animal believed to have once roamed the entire Terai Arc Landscape in Nepal and India along with the greater one-horned rhino and wild buffaloes.
Of the seven barasinghe translocated to Chitwan, officials recovered the bodies of six animals that had died. But the body of the lone survivor was never recovered, and was presumed dead.
The deaths, which halted the entire translocation program with a goal of moving 25 animals and cast a shadow over efforts to save the isolated population of the animals, was already facing a host of threats. But as translocation — which is key to the species’ survival — may require more careful consideration and study, there are other measures that can be taken to save the swamp deer, a recent study suggests.
“Connectivity between habitats in India and Nepal and habitat management in potential habitat areas targeted at swamp deer could help to a large extent.” says Bijaya Dhami, lead author of the study.
As part of the study, the authors used a computer program (called MaxEnt) to analyze different types of topographical attributes for the whole of Nepal’s western Terai, such as the altitude of the land, how steep it is and how close it is to water. They also looked at where the deer currently live and where they used to live. The computer program used all of this information to produce a map that shows where the deer are likely to live. The authors then checked the accuracy of the map using different methods and found it to be pretty good at predicting where the deer live.
Around 2,200 swamp deer live in and around Suklaphanta; a population of a couple hundred is estimated at Bardiya. Conservationists fear that the national parks are increasingly getting isolated from other protected areas in the country such as Chitwan farther east, which is also prime habitat for the Bengal tiger. The animal, which was historically found as far west as Pakistan and east as Bangladesh, is now limited to Nepal and India.
This could mean a lot of inbreeding among animals such as swamp deer, leading to a decline in genetic diversity and resistance against various diseases. They fear that a fatal disease could potentially wipe out the entire population.
According to IUCN, the global conservation authority, land use changes brought about by people farming and development of human settlements has impacted the population of barasinghe, which it classifies as vulnerable, throughout its entire range. This makes it hard for the deer to find food and water and also makes them more likely to die from diseases, bad weather or hunting. Some people also hunt the animal for its meat and antlers, even though it is not tasty. Fires, weeds and cows eating their grass have also affected them adversely.
The authors of the study found that nearly 65% of the area potentially suitable for swamp deer in Nepal’s western Terai falls outside of protected areas. “As swamp deer are grassland habitat specialists, it might be the case that they find grassland management regimes outside of protected areas more favorable,” Dhami tells Mongabay.
Every spring, national park authorities in Nepal’s Terai use machines to cut tall grasses and even set them on fire to “prepare suitable habitats” for tigers. But that doesn’t happen outside protected areas when humans manually cut grass to feed livestock.
“Our study also suggests that the protected area system needs to be expanded to include largest patches of suitable habitat that now lie outside protected areas,” Dhami adds. “Similarly, we need more connectivity between habitats in Nepal and India through transboundary conservation initiatives,” he says. The population of the swamp deer in the neighboring Indian national parks of Dudhwa and Pilibhit have a reported population of around 3,500 individuals. Their movement to and from Bardiya and Shuklaphanta has been seen as vital for the long-term survivability of the species.
The study also suggests that policies should be devised to conserve water sources, manage wetlands, reduce encroachment on grasslands and control anthropogenic expansion in the potential habitat of these species. Swamp deer can be used as an “umbrella species” for habitat management, which would also benefit other habitat-specialized herbivores of grasslands and wetlands, the authors of the study note.
Researcher Babu Ram Lamichhane, who wasn’t involved in the study, says that although the findings provide some valuable insights, there are certain limitations of MaxEnt models. “We have seen that MaxEnt models only take the presence of the species in certain areas into account, and its results may not be accurate,” he adds. Lamichhane, whose team carried out a habitat suitability study of barasinghe in Chitwan National Park, says the grasslands that swamp deer require may not be present outside protected areas.
There are also concerns related to the safety of barasinghe outside protected areas, conservationists say, as cases of deer hunting have also been reported in the Terai.
Lamichhane says that although connectivity between populations in India and Nepal needs to be improved, existing corridors are still functional. “We have seen that animals also use farmlands to move between the two countries,” he adds.
He says there’s no alternative to translocating barasinghe to Chitwan, where suitable habitats have been found. That will ensure that Nepal has two meta populations as envisioned by the government’s Strategy and Action Plan (2015-2025), Terai Arc Landscape Nepal.
“The last translocation attempt failed, as it didn’t provide an intervention at scale,” says Lamichhane. “We should have translocated at least a few hundred animals so their impact would be felt in Chitwan,” he adds.
An official at the Department of National Parks and Wildlife Conservation says the government doesn’t have any plans to translocate barasinghe anytime soon. The official says that donor agencies haven’t expressed their interest in funding such endeavors, and the government doesn’t have the resources to do it on its own.
Banner image: Swamp deer prefer grassland habitats. Image by David Raju via Wikimedia Commons (CC BY-SA 4.0).
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Citation:
Dhami, B., Adhikari, B., Panthi, S., & Neupane, B. (2023). Predicting suitable habitat of swamp deer (rucervus duvaucelii) across the western terai arc landscape of Nepal. Heliyon, 9(6). doi:10.1016/j.heliyon.2023.e16639
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