In Nepal, Herbs Used in Tibetan Medicine Are Getting Harder to Find

Research has found that at least 300 of the more than 2,300 species of medicinal and aromatic herbs found in Nepal are actively traded. Many medicinal herb hotspots lie within protected areas, such as Shey Phoksundo National Park, which covers much of Dolpo, and 39 percent of these traded species fall into one or more international conservation categories. Such an endangered status usually leads to a ban or quota being implemented on collection by the Nepali government.

However, low institutional capacity combined with the remote, challenging terrain of collection sites, makes implementation of rules difficult, explains Suresh Ghimire, a professor of botany at Tribhuvan University in Kathmandu. “The government officials in different [regulatory] bodies do not have the expertise to identify the plant,” he tells me. So protected plants are still traded often, sometimes camouflaged among other products.

And now climate change has become a significant added stressor, altering how and where the plants amchis collect can be found, Yungdrung asserts. It is also impacting other trees and crops that people in the region rely on, he adds, citing the example of apples, which he remembers as growing only in the Dunai area — a lower-altitude region of Dolpo. Now apples are found in areas of Dolpo at altitudes almost 2,000 meters higher than Dunai. “I see the same happening with all plants,” he says.

IN KATHMANDU THAT winter, I meet Suresh Ghimire in a chilly, university lecture-room filled with wooden, metal-framed benches, and posters of Nepali fauna taped to the peeling walls. We move to the balcony and the warmth of the winter sun, and Ghimire dusts off two wooden stools. Dressed in a checked, flannel shirt and black puffer jacket, he looks out over the university’s untended garden and talks softly of the effect climate change is having on medicinal herbs.

Ghimire was part of a team that studied how climate change is impacting Himalayan alpine vegetation, especially rare, endemic, and useful species. The study identified altitude — a proxy for temperature — and precipitation as the two factors that have the most significant impact in determining Himalayan alpine vegetation. While the relationship is complex, the study shows that, overall, medicinal herbs grow, bud, and flower better in areas of cold temperatures and higher rainfall.

Regions from 2,000 to 5,000 meters in altitude are particularly important habitats for medicinal plants, Ghimire says. “The medicinal plants are medicinal precisely because of the stress that they receive from the environment. When the environment is harsh — like in the northern parts of Nepal — the plant must produce more chemicals to defend itself.”

The warming climate has already resulted in Himalayan species shifting upwards in altitude, he says, a trend that will continue into the future, as temperatures go on increasing. Himalayan regions are expected to warm at twice the rate of the world average, which would exacerbate the problem.

As temperatures continue to increase, it is possible some species may run out of suitable habitats, being left with nowhere to go. A scarcity of soil at altitudes above 5,000 meters creates an upper boundary for growth. When there is nowhere left to migrate to, plants will either have to compete and adapt, or die, Ghimire tells me.

The Kathmandu-based Global Institute for Interdisciplinary Studies (GIIS) led a recent study examining possible changes in the habitats for 29 species of medicinal herbs across Nepal. Its modeling predicted future climate changes may reduce the areas climatically suitable for two-thirds of the studied species, and that 40 percent of hotspots with suitable climatic circumstances for a maximum number of species would disappear in the future.

Climate change has become a significant added stressor, altering how and where the plants amchis collect can be found.

“Although the climate change impact is a very slow, gradual impact, once you cross the threshold — boom, gone, the habitat is completely unsuitable for certain species, completely wiping out certain species,” says Uttam Babu Shrestha, director of GIIS and lead author of the study that Ghimire also participated in.

“These are hypothetical scenarios. Every species on Earth will [either] evolve or become extinct — this is what we call the natural extinction rate,” Shrestha says. “But with climate change, the extinction rate of some species will be thousands of times greater than the natural or baseline extinction rate.”

The threat that climate disruption poses to medicinal plants, not only in the Himalayas, but across the world, is a growing concern among researchers. In 2019, a group of scientists issued a report, “Scientists’ Warning on Climate Change and Medicinal Plants,” pointing out that 70 to 95 percent of citizens of most developing countries rely on these plants for their primary healthcare needs and that they are “increasingly utilized by large numbers of people residing in wealthier countries,” as well.

Indeed, awareness of the contribution of traditional medicine to conventional medical treatments is growing. According to World Health Organization (WHO) 40 percent of pharmaceutical products today derive from natural products and traditional knowledge. Examples include aspirin, derived from willow bark, and the childhood cancer drugs vinblastine and vincristine, which are sourced from Madagascar periwinkle. Tu Youyou, a Chinese chemist, was awarded the 2015 Nobel Prize in Physiology or Medicine for developing the antimalarial drug artemisinin. In 1971, she identified the chemical component responsible for the anti-malarial properties of sweet wormwood — a natural ingredient that had been used in Chinese traditional medicine for thousands of years.

Shrestha points out that global regulation and governance around the development of new pharmaceutical drugs are very strict, with the majority now being produced from bacteria grown in controlled, laboratory settings. “But, at some point in the future, we might need some biomolecules for new diseases, or new problems. From that point of view, we need to conserve,” he says.

THE FOLLOWING AUTUMN, I meet Yungdrung again at his clinic in Dolpo. The sky is dark, following many days of incessant rain, and we walk to a nearby lodge for a glass of local liquor by the wood-burning fire.

Our conversation turns to the future, and what should be done to preserve the medicinal herbs of the Himalayas. Historically, informal local rules encouraged careful use of these communal natural resources, Yungdrung tells me. Harvesting by an amchi would only take place after the performance of a ritual to the menlha, the medicine deity, and Tibetan medicine texts, studied by all amchis, describe guidelines for sustainable collection.

“Amchis always keep environmental conservation in their minds,” Yungdrung says. “Our method of harvesting actually helps replenish the herbs. A little picking is useful for the environment, but picking in huge amounts is detrimental.”

Ghimire’s research affirms that amchis harvest selectively, at many different levels. First, the time of collection is closely considered, depending on the part of the plant needed. Then sites are selected based on knowledge of the current distribution of plants, and within these, larger plants, or stronger or mature portions, will be chosen. Finally, only small amounts will be taken.

Yungdrung says that the more endangered herbs must be actively cultivated. “If they are completely lost then it will be very difficult in the future,” he says. (The 2019 scientists’ warning also recommends actions including “conservation and local cultivation of valued plants, sustainability training for harvesters and certification of commercial material, [and] preservation of traditional knowledge,” in addition to efforts to mitigate climate change.)