People use one-third of the plants that grow in the Amazon.
Across the world’s most famous rainforest, more than 400 Indigenous groups draw on thousands of native plants — for food, medicine, building materials and ritual. The knowledge on how to use these plants has been passed down through oral tradition, forming what researchers call a “living library.”
A new study warns that library is shrinking.
Research led by Rodrigo Cámara Leret at the University of Zurich, working with Conservation International scientist Patrick Roehrdanz, found that Amazonian peoples use at least 5,796 plant species — more than a third of the region’s known flora. It’s the first study to put hard numbers on how climate change threatens that body of knowledge.
The findings offer a warning: Indigenous cultures in Amazonia could lose an average of 28 to 34 percent of the plant species they use by 2080. Many of the plants people rely on most are already rare, confined to just a few places — and are increasingly at risk from climate change. The losses would be local — plants disappearing from the specific areas that cultures depend on.
“The future of biodiversity and the future of Indigenous knowledge are deeply connected, and neither can be fully understood in isolation,” said Roehrdanz. “This study documents the potential risks to that interconnected system and provides an opportunity to plan ahead.”
When a plant disappears, so does its name, its uses and the accumulated knowledge of its role in the forest. The research suggests that the web of plants and the knowledge that makes them useful is on track to shrink by 26 percent by 2080.
“It turns out that the plants that Indigenous communities rely on could be decimated more severely than previously thought,” says Cámara Leret, adding: “The climate tipping point for Amazonia will not only impact biological diversity but cascade across the unique cultural heritage of the biome.”
The disappearance of plants deep in the rainforest could impact us all.
Some of the plants that Indigenous communities use could turn out to be wild ancestors or close cousins of the world’s food and fiber crops. And as climate change increases, the world may need them.
Most of the world’s commercial crops have little genetic variation, which means they also have very little resistance to disease. As the world warms, diseases that impact our crops are spreading farther and evolving faster.
That makes wild genes from close relatives an increasingly important defense.
Cacao makes the case plainly. Witches’ broom disease has devastated cacao yields across Latin America — part of why Brazil, once a leading cacao exporter, has been a net importer since the 1990s. Some of the strongest resistance genes breeders have found trace back to wild cacao collected from river basins across the Brazilian Amazon.
The study’s dataset also includes species that matter enormously to regional diets and economies but have been largely ignored by big agricultural research programs focused on staples like wheat, corn or soybeans. Peach palm, one of the food species the study lists, is a textbook case. Prized across the region for its fruit and heart-of-palm, it has been under-studied by breeders as a potential crop. This matters to the wider world, in which just nine crops account for two-thirds of global production — an enormous bet on a very small number of species, which could become vulnerable to climate change.
To advance the protection of the at-risk species, the team has made its underlying database public. More than 76,000 literature reports on Amazonian plant use have been compiled as a resource for scientists, policymakers and the Indigenous communities working to protect their way of life.
For Roehrdanz, the message is clear. Climate change won’t just reshape the Amazon’s biodiversity — it will reach into the region’s languages and cultures, threatening careful tending formed over millennia.
“The plants are important. We all need them, and Indigenous cultures especially need them,” said Roehrdanz. “But the thing we must recognize and work to protect is a relationship — the connection between plants and people.”
