The forest of knowledge under global change

Amazonia harbours more than 10% of the terrestrial biodiversity of the Earth¹ and more than 400 Indigenous groups². So far, however, no study has assessed how climate change and the loss of Indigenous languages may simultaneously impact its biological and cultural heritage. Here, to bridge this gap, we first assembled a database of 90,536 reports from 700 references to understand the societal benefits that native plants provide across all countries of the Amazon basin. We found that humans utilize 5,796 native plant species, which amounts to one-third of the known Amazon vascular seed plant flora. Next, analysing 8,429 species distribution models across three future climate scenarios (SSP1-2.6, SSP3-7.0 and SSP5-8.5), we show that climate change will produce a greater reduction in the ranges of utilized than of non-utilized species by 2060-2080. Locally, Indigenous cultures may lose an average of 28-34% of their utilized plant species and 18-23% of their associated services from climate change. Regionally, the loss of threatened Indigenous languages may result in a 26% reduction in the Amazonian knowledge pool. Overall, our results point to the strong climate and language vulnerability of Amazonian biocultural heritage. At the same time, these results-together with our publicly available dataset-may serve to guide biocultural restoration and reverse the growing global change effects on ecosystems and cultural traditions.