Researchers have discovered two dozen ancient structures hidden beneath the canopy of trees in the Amazon rainforest basin.
The structures are earthworks that were built in the pre-Columbian period, i.e. before the period of European colonization. They represent the remains of a variety of sites and structures built by ancient indigenous peoples.
The previously unknown earthworks include the remains of an ancient city and fortified villages; defensive and ceremonial buildings; as well as rectangular and circular features known as geoglyphs; among other constructions, according to a study published in the journal Science.
Indigenous societies are known to have lived in the Amazon for at least 12,000 years, creating earthworks and domesticated landscapes that have had lasting impacts on the forest.
However, the extent of these societies’ influence on the forest remains poorly understood. This is primarily because evidence of it is very difficult to find due to the density of the forest canopy and the remoteness of many archaeological sites.
However, in the latest study, a large international team of researchers used light detection and ranging (LiDAR) technology to examine more than 2,000 square miles of the Amazon basin and were able to identify 24 previously unknown earthworks.
LiDAR essentially allows scientists to see through the forest canopy and create detailed 3D models of the surface features, including any unknown structures underneath.
“Our study suggests that the Amazon rainforest may not be as pristine as many believe, because as we seek a better understanding of the extent of pre-Columbian human habitation, we are surprised by a significant number of sites that are still unknown to science “community,” Vinicius Peripato, a doctoral candidate in remote sensing at the Brazilian National Institute for Space Research (INPE) and co-lead author of the study, said in a press release.
“From the 3D models of the surface, it is possible to digitally remove all vegetation and initiate a precise and detailed study of the terrain beneath the forest.”
The scientists then modeled the presence of other ancient earthworks across the Amazon and predicted that there are about 10,000 to 24,000 waiting to be discovered in the region.
The latest findings shed new light on the influence of pre-Columbian societies in the Amazon region.
“Some time ago, ecologists viewed the Amazon as a vast, pristine forest, but now, when we combine other types of pre-Columbian remains, we can see how many areas that currently host dense forest have already undergone extensive engineering work, management and management “Domestication of plants by pre-Columbian societies,” Carolina Levis of the Federal University of Santa Catarina in Brazil said in the press release.
“These people mastered sophisticated techniques for land and plant management that, in some cases, are still present in the knowledge and practices of contemporary communities and can inspire new ways of coexisting with the forest without the need for its destruction.”
The LiDAR survey data collected for the study covered only 0.08 percent of Amazonia’s total area, but researchers wanted to better understand where and how many undocumented pre-Columbian sites there might be in the region.
To do this, the scientists combined data from their relatively small survey with findings from previously identified sites to create a predictive model that could estimate the presence of pre-Columbian structures.
This model showed that between 10,272 and 23,648 large pre-Columbian structures remain to be discovered, particularly in southwestern Amazonia.
In addition, the researchers found a connection between the predicted locations of earthworks and the abundance of dozens of domesticated tree species. This suggests that active pre-Columbian indigenous forest management practices have long shaped the ecology of modern forests across the Amazon.
“Amazon forests clearly deserve protection not only for their ecological and ecological value, but also for their high archaeological, social and biocultural value, which can teach modern society how to sustainably manage its natural resources,” the authors write in the study.