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Davos, Switzerland

Medicinal Knowledge Vanishes as Indigenous Languages Die

Uldarico Matapí Yucuna, 63, is often called the last shaman of the Matapí, an Indigenous group of fewer than 70 people living along the Mirití-Paraná River in the Colombian Amazon rainforest. His father was a shaman and taught him ancestral knowledge, including how to use plants to treat all kinds of maladies. But Uldarico rejects the title because instead of living with his people, for the past 30 years he has been in Bogotá documenting in writing what is left of this knowledge.

Once a nomadic people, in the 1980s the Matapí were forced to live on a reservation with five other ethnic groups, where traditions and language, already threatened by colonization, withered further. “We are losing the essence of our spiritual knowledge of medicinal plants,” says Uldarico, whose last name is that of his tribe. “A knowledge that cannot translate into other languages.”

A study presented at the 2022 World Biodiversity Forum here in Davos, Switzerland last week reveals that many Indigenous groups face Uldarico’s dilemma. By linking linguistic and biological information, the authors show that most Indigenous knowledge about medicinal plants is linked to threatened languages, and that language loss is an even greater danger to the survival of such knowledge than biodiversity loss.

“Every time an Indigenous language dies, it's like a library is burning, but we don't see it because it's silent,” says study co-author Rodrigo Cámara Leret, a biologist at the University of Zürich (UZH).

Of the 7000 Indigenous languages still spoken, 40% are in danger of disappearing, according to the United Nations. And 80% of the world’s remaining biodiversity is in Indigenous territories.

In the new study, researchers scoured the literature, including early records by colonizers, to map medicinal plant uses and Indigenous languages in three regions—North America, the northwestern Amazon, and New Guinea. They found about 12,000 medicinal uses for more than 3000 plants, known to people who speak 230 Indigenous languages in these regions. But more than 75% of this knowledge resides in only one of these languages.

Such knowledge is diverse. The Tucano of the Rio Negro in Brazil, for example, use bark from the tree Leptolobium nitens in arrows to paralyze animals they hunt. The Siona people in Colombia and Ecuador apply a milky latex from the tree Euphorbia hirta to treat fungal foot infections.

“The majority of this knowledge is unique,” says Jordi Bascompte, an ecologist at UZH and co-author of the study, which was also published in the Proceedings of the National Academy of Sciences. “If the language disappears, it's lost.”

The United Nations lists all Indigenous languages in the western Amazon as endangered—making the accumulated botanical knowledge of those groups endangered too. In North America, endangered languages account for 86% of the unique knowledge about medicinal plants; the figure is 31% in New Guinea, according to the study.

The authors say such knowledge starts to erode even before languages go extinct. In some groups studied, current speakers no longer recognize medicinal plants or don’t know what mixtures to make and how to prepare them, Cámara Leret says. “There are no apprentices,” he says. “With oral traditions, if you don't tell it to others while you are alive, it disappears.”

Uldarico adds that translation isn’t enough to transmit his culture’s knowledge of how to use plants to heal. A shaman is like a pharmacist as well as a physician, with knowledge that goes well beyond plant identifications that could be translated or simple matching of a plant to a symptom, he says.

Much knowledge may already have vanished without being recorded, the researchers note. “We only covered the tip of the iceberg,” says Cámara Leret.

In contrast to the high proportion of threatened languages, less than 4% of medicinal flora in the three regions covered by the study is at risk of extinction.

“We are losing knowledge at a higher rate than biodiversity,” Bascompte says.

The results are consistent with previous research, says Victoria Reyes-García, an anthropologist at the Catalan Institution for Research and Advanced Studies. Her team’s study with the Tsimane people of Bolivia showed adults have been losing about 3% of their knowledge about plant uses every year, much higher than estimated rates of overall biodiversity loss in the world.

Without Indigenous knowledge, precious natural compounds that could generate drugs might get lost. Fewer than 5% of the medicinal plants used by the Ticuna people, whose ethnobotanical knowledge is one of the best-studied in the Amazon, have been screened for their biological activities, Cámara Leret says.

Indigenous cultures hold ancient knowledge beyond that of medicines, adds linguist Ana Vilacy Galucio, at the Emílio Goeldi Paraense Museum in Brazil. “Indigenous languages encompass entire knowledge systems about biodiversity, social organization, and the management of the environment,” says Galucio, who works on projects to document and revive Indigenous languages.

“The loss of culture is also a loss of our ability to adapt and find solutions to the increasing environmental problems,” adds Tania Eulalia Martínez Cruz, an Ayuuk Indigenous woman from Mexico and a social science researcher at the University of Brussels.

She notes, for example, how Indigenous people from Oaxaca in Mexico have developed ways to grow plants during droughts.

For Uldarico, threats to culture and the environment are two sides of the same coin. “The complexity of medicinal plants is a territorial knowledge,” he says. “When you destroy a territory, you destroy nature, knowledge, our practices, and our life.”

This story was produced as part of a Biodiversity Media Initiative travel grant to the 2022 World Biodiversity Forum in Davos, Switzerland. It was originally published in Science on 6 July 2022 and has been lightly edited for length and clarity. The Biodiversity Media Initiative is supported by Arcadia — a charitable fund of Peter Baldwin and Lisbet Rausing. 

Banner image: A Ticuna man in Colombia boils water with medicinal plants to treat his wife's leg pain. His language and others in the Amazon are endangered, putting medicinal knowledge at risk / Credit: Mayela Lopez, via Getty Images.