Amazon Plant Knowledge Faces Climate Change and Language Loss

For generations, Indigenous peoples throughout the Amazon have developed a remarkable understanding of the plants that surround them.

Yet climate change and the loss of languages now risk wiping out a substantial share of that knowledge.

A recent study reports that Amazonian communities use almost 5,800 native plant species for food, medicine, construction materials and cultural purposes.

Should the region’s most endangered languages die out, roughly one-quarter of this shared plant knowledge could disappear alongside them.

Charting centuries of Amazon plant knowledge

Amazonia has attracted plant collectors and naturalists for centuries. Anthropologists have also long called it a living library, reflecting the profound forest knowledge held by its peoples.

Rodrigo Cámara-Leret, a botanist at the University of Zurich (UZH), and his colleagues set out to unite this dispersed evidence in one comprehensive record.

The researchers compiled over 90,000 reports from 700 sources published from 1504 to 2023, spanning every country reached by the Amazon basin. The material therefore covers more than five centuries.

Amazonian peoples use no fewer than 5,796 native plant species. This represents around one-third of the seed plants known in the region and approximately twice the total identified by previous reviews.

Plant knowledge extends far beyond medicine

Palms feature most prominently in the records. All five of the most commonly reported species are palms, including the peach palm, whose carbohydrate-rich fruit has nourished people for millennia, and wild açaí, now widely sold in urban markets.

Across the basin, palms continue to underpin everyday life by providing food, fibre and building materials.

Research has concentrated strongly on healing: medicinal plants attracted almost three times as many reports as species used as food.

Indigenous communities possess the greater part of this knowledge, reporting four times more useful species than neighbouring non-Indigenous populations.

To examine how different cultures arrange this knowledge, the researchers expanded on an earlier study that represented each culture’s plant lore as a network connecting species with their varied uses.

Useful plants could suffer heavier losses

After establishing which plants communities depend upon, the researchers examined how climate warming could shift their distributions.

Patrick Roehrdanz of Conservation International carried out the modelling.

He mapped the current and projected future ranges of more than 8,000 species, estimating where each might continue to survive under three climate scenarios between 2060 and 2080.

One clear trend appeared. Plants with recorded human uses are expected to lose a larger proportion of their ranges than species with no documented use. Climate change therefore affects the plants carrying cultural importance most severely.

These losses accumulate within the territory of an individual culture. By 2080, communities may lose 28 to 34 percent of their useful plants locally.

Risks to medicine, food and livelihoods

Amazonian communities may also forfeit 18 to 23 percent of the benefits supplied by these plants, including food, medicine and construction materials.

Plants used medicinally seem particularly exposed, and the pressure is already evident.

A severe drought in 2024 reduced the following year’s Brazil nut harvest throughout the basin, raising prices and putting pressure on communities dependent on the crop for both food and income.

Other research has cautioned that the Amazon is approaching a tipping point at which drought, fire and deforestation could transform vast rainforest areas into drier savannah.

Those same stresses now seem to endanger the human knowledge associated with these forests.

Irreplaceable Indigenous plant knowledge

Plants account for only part of the issue. Much of this knowledge is bound to a specific language, and languages are vanishing even more rapidly than the plants themselves.

Of approximately 156 living Indigenous languages included in the records, more than half are classed as threatened.

Since so much plant knowledge is found in only one language, the disappearance of endangered languages would reduce the region’s total combined knowledge by around one-quarter, on the assumption that a language’s knowledge dies with its final speakers.

Under more pessimistic definitions of which languages are threatened, the loss rises to three-fifths.

Much of this information has been documented only during the last century, indicating that it remains actively used rather than merely preserving a historical record.

Plant and language loss converge

The same research group has previously demonstrated that language decline and knowledge decline occur together.

An earlier paper concluded that most medicinal knowledge in the Amazon and neighbouring areas belongs exclusively to a single language, with no other community retaining the same information as a backup.

Before this study, ecological and linguistic evidence had not been brought together to assess both dangers simultaneously across the full basin.

Combining them showed that the pressures do more than add together: they overlap. They affect the same cultures and plants, so a community may lose both a plant and the language for using it in a single generation.

Protecting nature and knowledge at once

One finding is especially clear: Amazon plant knowledge is confronted by two threats simultaneously. Climate change is moving useful species beyond reach, while language loss may destroy the knowledge of what those plants are used for.

Neither danger had previously been assessed at this scale.

To support efforts to reverse this trend, the team has made its complete record of more than 76,000 reports available as an open dataset for scientists, governments and Indigenous communities seeking to preserve this knowledge.

Because most of this knowledge is held by a single culture, the authors maintain that forest protection and language support must be pursued together.

What the world stands to lose

The consequences extend far beyond Amazonia. Amazonian plants have already supplied the world with staple foods and medicines, while thousands of species have received little scientific study.

Each language that falls silent could take with it a possible clue to a treatment or crop that nobody else ever recorded.

For now, the forest still contains this knowledge. Its survival through this century will depend on how swiftly the world curbs warming and how much assistance these communities and their languages receive.