Food drives bear-human conflict in Khangchendzonga Biosphere Reserve

In the famous cartoon series, Yogi Bear and his friend Boo-Boo frequently get into trouble with park rangers for stealing picnic baskets in the fictional setting of Jellystone National Park.

It turns out food is also the major driver of conflicts between Asiatic black bear (Ursus thibenatus) and humans in the iconic landscape of the Khangchendzonga Biosphere Reserve (KBR) in the eastern Himalayas, according to a new study.

Increasing bear-human conflict is also linked to rising temperatures in the Himalayan region in the last five decades and a delay in snowfall in December. This leads to a reduced hibernation period for black bears, the authors said.

The study underscored the importance of woody trees such as oak that produce various nuts and fruits as the staple food for bears in the KBR landscape, in the Indian state of Sikkim.

Under Mt. Khangchendzonga’s shadow, the KBR is witness to a unique syncreticism of religion, culture and environment protection.

But episodes of human-animal conflicts are gradually unfolding in the fringe areas surrounding the Khangchendzonga National Park (KNP), a high altitude park between 1220 metres to 8600 metres, that forms the core of the KBR wilderness.

KNP is India’s first Mixed World Heritage Site on UNESCO World Heritage List.

Crop damage by Asiatic black bear (Ursus thibenatus), wild boars, monkeys and porcupines are reported regularly. However, the indigenous communities like Lepchas and Bhutias, who revere Mt. Khangchendzonga as their “guardian deity”, have displayed a high level of tolerance because of their Buddhist beliefs.

In the state, incidents of bears mauling people are not uncommon. Of late, concerns have been raised about Sikkim’s organic mission being at stake due to crop depredation by wild animals.

Recently, Sikkim’s chief minister Pawan Chamling empowered farmers and villagers to defend their crops and livestock from wild animals by chasing them away with sticks and stones, and said that no legal action would be taken if the wild animal dies in the process.

According to the KNP Management Plan (2008 to 2018), the threat of Asiatic black bear in many fringe villages around the national park is “quite serious” with considerable destruction of cardamom and maize crops reported in some areas. In some cases, bears are also known to kill and prey on poultry, domestic beehives, and domestic pigs.

In the latest study that could inform management plans, scientists from Wildlife Institute of India (WII) have shown incidents of black bear-human conflict usually shoot up towards the end of autumn season (October-November) coinciding with the pre-hibernation phase of the bears.

During this phase the bears tend to hoard up excess fat to see them through their long winter sleep. They do this by feeding intensively on fruits of oak trees (acorns), a staple in the fall season. In their quest for food at this time, Asiatic black bears tend to travel long distances.

So their presence is strongly associated with acorn producing trees in broadleaved forests at lower elevations. 

“And failure in acorn production due to droughts or acorn collection by locals deplete the food availability. This forces the bears to move out of their natural habitat and raid crops and attack livestock in the nearby villages,” lead author of the study S. Sathyakumar, a WII scientist, told Mongabay-India.

Asiatic black bears are large carnivores that have large annual home ranges that for some males could even spread out up to 150-200 square km, according to the scientist.  They are not sedentary animals and move great distances during spring and autumn for foraging.

Immediately after emerging from their slumber, the bears feast on herbs, fruits and seeds of shrubs, trees and montane bamboo. The bears also prey on sick, old, injured wild or domestic animals and scavenge on dead animals for protein.

Their dietary habits influence species composition and dynamics of forests because they act as both seed dispersers in case of small berries and seed destroyers in the case of large fruits and seeds, Sathyakumar said.

Against this backdrop, the authors drew attention to the importance of protecting the sweeping, largely evergreen broadleaved and coniferous forest patches of KBR (between 1700 metres to 2400 metres) that provide food and denning sites to the bears, Sathyakumar said.

“Bear managers need to consider the value of mast-producing (fruit and nut bearing) trees as the staple food for bears and keep a check on acorn collection by locals. Black bears have excellent memory and their primary agenda is to track food,” Sathyakumar pointed out.

Moreover, bamboo species are frequently collected by local people of Sikkim for a variety of applications — for instance, young shoots are used as food, leaves as fodder, and different plant parts for fencing, supporting prayer flags, making mats, baskets and animal sheds. This reduces food supply for bears and increase incidences of bear-human conflict in the black bear habitat, he explained.

The Sikkim forest department, which has guidelines in place for dispensing compensation for life and property losses during human wildlife conflicts, acknowledged that food scarcity is a factor.

“During lean period, they may not be getting adequate food and the public maybe collecting nuts and tubers, so some food scarcity is there. We think that phenology of trees is being affected due to climate change and this also changes fruiting and seeding time impacting bear food availability,” CS Rao, Sikkim’s chief wildlife warden told this visiting Mongabay-India correspondent.

Also acknowledging the ramifications of Chamling’s announcement, forest department sources said that while there is no official order yet on the chief minister’s declaration on chasing away wild animals, the “matter is under consideration of government for appropriate action.”

Sathyakumar argued that chasing a wild bear with sticks and stones may not be advisable and can be life threatening.

Instead, villagers could use traditional methods such as physical guarding (along with domestic dogs), making noises by beating of empty tins, using fire as a deterrent at the forest-village boundary and barbed wire fencing wherever possible to protect crop depredation by black bears. Modern tools such as using fox lights, bear repellents, could also come in handy, he said.

Birkha Man Subba, an elderly resident of Yuksom village on the edge of the biosphere reserve, agreed. Subba worked with the forest department before Sikkim became a part of the Indian union in 1975 and also after that.

“Some methods have to be deployed to keep them away. Wild animals come to the agricultural fields. Deer eat pea and bears eat maize. We can’t hurt them. Perhaps, fencing can fend them off,” Subba, who now runs a homestay with the local NGO Khangchendzonga Conservation Committee (KCC), said.

Lalit Kumar Sharma of Zoological Survey of India, who was not associated with the study, opined that forest managers have to try out variety of methods and strategies that not only minimise conflict but also reduces the future probability of conflict cases, so that the local communities do not develop antagonistic behaviour against bears.

One of them is “aversive behavioural conditioning” which refers to consistent conditioning of bears to avoid people and human food resources.

“For example repeated negative (threatening, uncomfortable, or painful) stimuli (e.g., cracker shells, rubber bullets, pursuit by dogs, emetic chemical that induces vomiting or diarrhoea, etc.). Although it may be costly but should be combined with efforts to remove all attractants,” Sharma added.

Rao said presence of garbage also is a factor in drawing out bears to human settlements in other parts of Sikkim. But Sathyakumar emphasised that trash is not an issue along the major trekking trail in KBR-KNP as the local NGO conducts ‘Zero Waste’ management for the trekkers.

Site-specific conservation needed for bears in KBR landscape

The KNP/KBR complex covers nearly 36 percent of Sikkim and showcases a diverse range of ecosystems from subtropical to alpine. It is one of the largest protected areas in the Kanchenjunga transboundary landscape shared by Bhutan, Tibet Autonomous Region of China, India, and Nepal.

Using sign surveys, trail monitoring, camera trapping and modelling, the scientists discovered that the black bears  are picky about their habitats. Almost all the black bear evidences (98 percent) were recorded from temperate and subalpine habitats.

Only 5.35 percent of the biosphere reserve is highly suitable for black bears and these areas are mostly located in the buffer zone outside the KNP boundary that makes them more prone to conflicts, the study revealed.

The black bear is a “habitat specialist” that prefers sites in temperate-riverine habitat at lower elevations indicating the significance of local landscape.

Population estimation for black bears has not been carried out in the KBR and no reliable information on true abundance estimation is available so far.

“In the KBR landscape, the settlements are adjacent to the buffer zone, and all the human settlements include riverside woodlands, farmlands, nurseries, plantations, villages and even towns. Since such areas can provide rich summer food (including cultivated crops) to bears, these areas are more prone to conflict,” Sathyakumar said.

These findings encouraged the researchers to recommend a site-specific conservation and management strategy for the black bears of Khangchendzonga.

“There is a pressing need to protect, maintain and strengthen these primary patches of suitable habitat of black bears,” he said.

The current distribution model identified important areas for black bear that could act as feasible sinks that facilitate animal movements between the Sikkim bear population and the adjoining population in Nepal, the study said.

A few small regions in the Rangyong and Lachen catchments also have high potential to act as secondary sites for bear habitat restoration and management.

In addition to radio-telemetry studies for detailed insight into the habitat use and movement pattern of bears, the authors also suggest studies to analyse potential corridors that allow the genetic exchange.

“There is a high scope for detailed molecular genetics study of bear population across the Khangchendzonga landscape of Sikkim, Nepal, Bhutan and China-Tibet to know about the genetic viability of the population, gene-flow and genetic connectivity with adjacent populations,” Sathyakumar said.

CITATION:

Bashir, T., Bhattacharya, T., Poudyal, K., Qureshi, Q., & Sathyakumar, S. (2018). Understanding patterns of distribution and space-use by Ursus thibetanus in Khangchendzonga, India: Initiative towards conservation. Mammalian Biology, 92, 11-20.

Banner image: Asiatic black bear. Photo by Joydeep/Wikimedia Commons.