The Amazonian rainforest was transformed over two thousand years ago by ancient people who built hundreds of large, mysterious earthworks.
The research was carried out by Jennifer Watling, post-doctoral researcher at the Museum of Archaeology and Ethnography, University of São Paulo, when she was studying for a PhD at the University of Exeter.
Findings by Brazilian and UK experts provide new evidence for how indigenous people lived in the Amazon before European people arrived in the region.
The ditched enclosures, in Acre state in the western Brazilian Amazon, were concealed for centuries by trees. Modern deforestation has allowed the discovery of more than 450 of these large geometrical geoglyphs.
The function of these mysterious sites is still little understood – they are unlikely to be villages, since archaeologists recover very few artefacts during excavation. The layout doesn’t suggest they were built for defensive reasons. It is thought they were used only sporadically, perhaps as ritual gathering places.
The structures are ditched enclosures that occupy roughly 13,000 km2. Their discovery challenges assumptions that the rainforest ecosystem has been untouched by humans.
Dr Watling said: “The fact that these sites lay hidden for centuries beneath mature rainforest really challenges the idea that Amazonian forests are ‘pristine ecosystems`.
“We immediately wanted to know whether the region was already forested when the geoglyphs were built, and to what extent people impacted the landscape to build these earthworks.”
Dr. Watling said: “Despite the huge number and density of geoglyph sites in the region, we can be certain that Acre’s forests were never cleared as extensively, or for as long, as they have been in recent years.
“Our evidence that Amazonian forests have been managed by indigenous peoples long before European Contact should not be cited as justification for the destructive, unsustainable land-use practiced today. It should instead serve to highlight the ingenuity of past subsistence regimes that did not lead to forest degradation, and the importance of indigenous knowledge for finding more sustainable land-use alternatives”.