Ancient peoples shaped the Amazon rainforest

An international team of ecologists and social scientists, including french researchers from IRD, Cirad and Inra, has shown in a new study published on 3 March 2017 in the journal Science that tree species domesticated and distributed throughout the Amazon basin by indigenous peoples before 1492 continue to play an important role in modern-day forests. These new findings strongly refute the idea that Amazonian forests have been largely untouched by humans. The team made the discovery by overlaying data from more than 1000 forest surveys of the Amazon Tree Diversity Network on a map of more than 3000 archaeological sites across the Amazon. By comparing forest composition at varying distances from archaeological sites, their analysis generated the first Amazon-wide picture of how pre-Colombian peoples influenced Amazonian biodiversity. The study focused on 85 tree species known to have been domesticated by Amazonian peoples for food, shelter, or other uses over the last several thousand years. The researchers found that throughout the Amazon basin these species were five times more likely to be common in tree surveys than non-domesticated species. Domesticated species were also found to be more common and more diverse in forests closer to archaeological sites.