Ancients transformed landscape of the Amazon, researchers find

Ancient people likely had an architectural role in the Amazon’s plant life, a theory that contradicts the long-held belief the Amazon’s biodiversity is by nature’s design.

Brazil nut

The Amazon is an immense network of vegetation, waterways and wildlife. For centuries, it has also been home to people, both indigenous and settlers. Some tree species are common there today because they were intentionally grown, or domesticated, by the people who lived there long before the arrival of European settlers. These include cacao, açaí and Brazil nut.

FIU botanist Christopher Baraloto is part of an international research team that examined 85 types of trees known to have been used by indigenous people for food, medicine and shelter across 3,000 archaeological sites. The study, recently published in Science, found these species are more common in mature forests than non-domesticated species, and they are more common in forests closer to where people once lived.

“It is now clear plant domestication by Amazonian peoples had a clear, broad and long-lasting impact on modern forest structure and composition,” Baraloto said. “Ongoing collaborative research projects will further resolve the extent to which forest composition is linked to archaeological sites in the region.”

This is the first study to paint a picture of how indigenous peoples influenced plant and animal diversity across the Amazon. This was not an easy task considering the Amazon’s vast size — it spreads across nine countries, hampering archaeological research. Its vastness is also why scientists may have had the misguided belief the Amazon’s biodiversity was naturally occurring.

Although the number of tree species examined in this study is small, it is enough to show the strong influence ancient people have had on today’s forests. In fact, their influence may be even stronger since hundreds of other tree species were used by the indigenous people of the Americas, the researchers point out. These ancient peoples began cultivating their favorite plants at least 8,000 years ago, and their descendants continue to grow many of those species today.

Baraloto is the director of the International Center for Tropical Botany, a collaboration between FIU and the National Tropical Botanical Garden. The study was led by the National Institute for Amazonian Research in Brazil and Wagenigen University and Research in the Netherlands.