Lack of large prey may be feeding rise in Nepal’s human-tiger conflicts

KATHMANDU — Until a few months ago, residents of Geruwa, a rural municipality in western Nepal, used to rush to their homes before dusk and shut themselves indoors. That was the only way they knew to protect themselves and their livestock from the tigers that would prowl this area on the fringes of Bardiya National Park, home to a third of Nepal’s endangered Bengal tigers (Panthera tigris).

“Those few months were particularly difficult for us as the tigers attacked both livestock and humans,” says Dharma Prakash Tharu, a spokesperson for the municipality. Although local authorities don’t have official data for the number of cattle lost, residents say almost every household has lost some of its animals to the tigers.

And it’s not just livestock: More than two dozen people have been killed by tigers in and around the national park in the past five years.

As the global community applauds Nepal’s achievement of nearly tripling its tiger population in 12 years, human-tiger conflict has emerged as one of the biggest challenges to conserving the big cats, with researchers exploring the potential causes and solutions.

One factor that has started receiving attention is the lack of “apex prey” for these apex predators in Bardiya National Park, home to 125 of Nepal’s 355 tigers.

“Based on the available data, we can say that the tigers in Bardiya prey on small and medium-sized prey such as spotted deer [Axis axis] and wild boar [Sus scrofa],” says conservationist Jhamak Bahadur Karki, who raised the issue at the recently concluded National Tiger Workshop in Bardiya.

Although such prey do provide nutrition for the tigers, the “energy maximizer” cats need to hunt several of these smaller animals to fill their stomachs, and that takes a lot of running around and spending energy. “In contrast, if a tiger kills large and medium-sized prey such as sambar, nilgai, wild buffalo or gaur, they need to kill less to get the same level of energy and nutrition,” Karki says. But nilgai antelopes (Boselaphus tragocamelus), wild water buffalo (Bubalus arnee) and gaur wild cattle (Bos gaurus) are completely absent from Bardiya, while sambar deer (Rusa unicolor) only occur in small numbers in the park.

With large and medium-sized `prey hard to come by, tigers see domesticated buffalo and cattle as better sources of food, for which they don’t have to spend much energy, conservationists say. And this is what leads to conflict with humans.

This issue has also been flagged in the government-commissioned report “Status of Tigers and Prey in Nepal 2022.” It says that although prey density in general (the availability of prey in a given area) has increased across tiger habitats in the country, the density of large prey species in particular remains low. In Bardiya, prey density increased from 78 to 90 animals per square kilometer between 2018 and 2022, but the biomass of these prey animals may not be adequate for the tigers, researchers say.

“Tiger is an apex predator and prefers larger size prey. With lower density of the large sized prey, tigers switch to smaller prey,” the report says. “Thus, focusing on increasing densities of large prey species should be a strategy to sustain the tigers in higher densities.”

Another study shows that large-sized prey species (sambar, gaur and nilgai) contributed more than 50% of the biomass consumed by tigers in Parsa National Park, in central Nepal, where the three species of herbivore are found. The researchers, who analyzed scat samples from tigers in and around the national park, found no traces of livestock in the diet of the tigers. This suggests a potential link between attacks on livestock and the availability of large-sized prey species.

Karki says he doesn’t believe it’s possible to translocate nilgai to Bardiya as they prefer the degraded types of grassland found in areas like Parsa. “I think, along with the swamp deer [Rucervus duvaucelii], we also need to translocate water buffalos and gaurs,” he says.

Historically, the tiger’s large-sized prey are believed to have been distributed along the Terai Arc Landscape, which straddles the border region between Nepal and India. But their population there shrank over time and became confined to a few fragmented habitats, according to conservationists.

Both the Arna Conservation Action Plan (2020-2024) and the Gaur Conservation Action Plan (2020-2024) identify the translocation of wild water buffalo and gaur to Bardiya as a means of diversifying the populations there. However, with the exception of the greater one-horned rhino (Rhinoceros unicornis), wildlife translocation efforts have largely failed to create alternative viable populations for species in Nepal. The translocations of swamp deer to Bardiya and wild buffalo to Chitwan National Park, for instance, have had limited success.

“I don’t think we can translocate [buffalo] to Bardiya,” says Rabin Kadariya, who until recently headed the Bardiya office of the semigovernmental organization the National Trust for Nature Conservation. “We don’t have enough swamps in Bardiya for the water buffaloes. But, yes, we need to have more large-sized prey for tigers in Bardiya.”

The government has also been looking into the issue following the publication of the tiger prey report. However, it doesn’t have concrete plans to translocate any animals as of now, says ecologist Ganesh Pant, a spokesperson for the Department of National Parks and Wildlife Conservation. “Translocating animals requires a lot of planning and monitoring,” he says.

Back in Geruwa, tiger incursions into the villages seem to have ended, says Tharu, the municipal spokesperson.

“We don’t know why, but it’s been around three months that we haven’t seen tigers in our area,” he says. “Maybe they will be back again soon and we will have to go through the ordeal again.”

Abhaya Raj Joshi is a staff writer for Nepal at Mongabay. Find him on Twitter @arj272.

Citation:

Lamichhane, S., Pun, P., Thanet, D. R., Regmi, P. R., Maharjan, A., & Lamichhane, B. R. (2022). Dietary composition and prey preference of Royal Bengal tiger (Panthera tigris tigris, Linnaeus 1758) of Parsa National Park, Nepal. European Journal of Ecology, 8(1). doi:17161/eurojecol.v8i1.15466

This article by Abhaya Raj Joshi was first published by Mongabay.com on 11 May 2023. Lead Image: A tiger photographed resting on a rock. Flickr (CC BY-NC-ND 2.0).

What you can do

Support ‘Fighting for Wildlife’ by donating as little as $1 – It only takes a minute. Thank you.