More than 10,000 pre-Columbian archaeological sites are hidden throughout the Amazon basin.
However, the size and scale of human occupation are not well known, and there has never been a comprehensive survey of pre-Columbian sites throughout the Amazon basin. That is, until now.
A new study published in Science has uncovered the Amazon’s hidden secrets and has found records from thousands of ancient indigenous communities hidden under its canopy.
The findings come from a new study published in Science and involved more than 230 researchers from 24 countries across four continents.
Led by Brazilian researcher Vinicius Peripato from the Brazilian National Institute of Space Research, it used remote sensors to reconstruct a highly detailed 3D model of the land surface beneath the forest canopy.
“The massive extent of archaeological sites and widespread human-modified forests across Amazonia is critically important for establishing an accurate understanding of interactions between human societies, Amazonian forests, and Earth’s climate,” Mr Peripato said.
Previously, airborne LiDAR (Light Detection and Ranging) has identified many unknown pre-Columbian structures and earthworks in the heavily obscured forests of Central and South America.
This technique uses light to scan and map the world below the forest canopy. It can detect and measure small changes in topography on the ground surface.
Using the data, the researchers searched 5,315 square kilometres of LiDAR survey data.
They discovered 24 unknown human-made structures in various locations across the basin, including fortified villages, defensive and ceremonial structures, mountaintop settlements, and geoglyphs.
The data used a predictive special distribution model that estimated that 10,272 and 23,648 large-scale pre-Columbian structures remain undiscovered, with a concentration in southwestern Amazonia.
The team also identified relationships between the predicted probability of earthworks and the occurrence and abundance of domesticated tree species.
Not only did they find a significant association between the two, but they also believe it reveals just how active pre-Columbian Indigenous societies were in forest management practices, which have had lasting influences on modern Amazonian ecology.
“Amazonian forests merit protection not only for their ecological and environmental value but also for their high archaeological, social, and biocultural value, which can teach modern society how to manage its natural resources sustainably,” the team said.
They were also impressed with the sophistication of some of the earthworks and irrigation works they discovered.
“These peoples mastered sophisticated land and plant management techniques,” according to Carolina Levis from the Federal University of Santa Catarina in Brazil.
“In some cases, those techniques are still known to present-day communities and could inspire new ways to coexist with the forest without the need for its destruction.”
For Australian researcher Professor Bill Laurence, the findings solve anthropologists’ questions about the Amazon basin.
Professor Laurence, a long-time Amazon expert at James Cook University, said the study “combines cutting-edge remote sensing with archaeological data and advanced statistical modelling to identify hidden earthworks—suggests more native people were living in the Amazon than many had imagined.”
“But they mostly lived in drier, more fertile areas where farming and forest burning was suitable.”
This groundbreaking study also has political implications for Brazil’s current debate on indigenous land demarcation.
“This research provides numerous pieces of evidence of indigenous peoples’ ancestral occupation of the Amazon rainforest, their ways of life, and the relationship they established with the forest.”
In April, Wood Central reported on research that suggests that indigenous communities in Brazil’s Atlantic Forests, who have attained full and formal recognition of land rights, have led to reduced deforestation and increased forest cover.
A University of Colorado Boulder study, which supports past research in the Amazon, analysed changes in forest cover in 129 indigenous communities between 1995 and 2016 and noted that legal tenure positively impacted reforestation.
The study showed that Indigenous peoples felt more encouraged to revise forests, safe in knowing they will be protected by law.