Hidden beneath the trees of the Amazon jungle are the archaeological remains of a once large village built by pre-Columbian indigenous communities before the arrival of Europeans in the Americas. The ancient city featured dams, artificial ponds, dikes, ditches, cemeteries, platform streets, and fish dams, and was located in what is now the Xingu River basin, south of the Brazilian Amazon. These ruins, hidden by the dense vegetation of the forest, were discovered by a group of scientists thanks to a special remote sensing system called LiDAR, which uses laser beams to map small changes in the topography of the jungle floor and allows reconstruction. in three dimensions what is on the surface.
Vinicius Peripato and Luiz Aragão of Brazil’s National Institute for Space Research led a more than five-year effort in which they flew drones and aircraft equipped with the LiDAR system over 5,315 square kilometers in a region of the Amazon. In this small area of land alone, which accounts for 0.08% of the seven million hectares of the world’s largest tropical forest, they found 24 new archaeological sites that resemble the ancient village. They then decided to combine their findings with a predictive spatial distribution model that allowed them to produce an estimate of earth movements caused by communities across the jungle more than 500 years ago. The results of the study, published this Thursday on the cover of Science magazine, show that between 10,272 and 23,648 large pre-Columbian archaeological structures remain to be discovered in the Amazon.
LiDAR data from excursions to examine slopes under the forest canopy. From top to bottom, the first is the set of LiDAR points colored by their height. This is followed by the slope of the terrain, the shading of the hills and the height of a series of embankments, all obtained after digitally eliminating the surface elements (forest). Vinicius Peripato
The origin of the work was a question that could not be answered without current technology: Where and how many pre-Columbian sites are hidden beneath the canopy of the Amazon forest? At the time of the study, scientists from the nine countries that make up the jungle (Brazil, Peru, Colombia, Bolivia, Venezuela, Ecuador, Guyana, Suriname and French Guiana) Using high-resolution satellite data from Google Earth, they had discovered nearly 950 archaeological sites. The problem was that only the earthworks that were in deforested areas could be seen. What lies beneath the trees remained hidden. The LiDAR system, which stands for “Light Detection and Ranging,” has changed everything.
In an interview with EL PAÍS, Peripato explains that this air sensor is an advanced remote sensing technology that has “revolutionized the way we obtain information about the earth’s surface and its three-dimensional properties.” You no longer have to go to the forest cut down to know what’s inside. In recent years, LíDAR has also been used to discover the complex urban and rural network that the Mayans had throughout Mesoamerica: “Mesoamerican archaeological sites have very different characteristics than those of the Amazon due to the variety of building materials: The Mayans used stone and.” The natives of the Amazon used the earth. “LíDAR technology has significantly improved our spatial understanding of archeology at sites with forested landscapes,” the scientific article says.
Peripato says that among the 24 archaeological sites they found defensive and ceremonial sites in the southwest Amazon, called geoglyphs. “The presence of urns at these types of sites and the absence of anthropogenic soils and ceramics are evidence that the use of these structures was limited to religious and community gatherings,” says the researcher. They also found mountains conquered by indigenous communities in the Guiana Shield that were used for ceremonial and domestic purposes, as well as riparian areas in the plains of central Amazonia that were used for fishing during the rise and fall of river levels.
Figures from earthworks in the Amazon landscape. Mauricio de Paiva
Carolina Levis, co-author of the paper and professor at the Federal University of Santa Catarina, explains in a press release that this research helps refute the popular idea that the Amazon is a vast jungle. “The work shows us that there are many areas of the jungle that were already the subject of extensive engineering, cultivation and plant domestication by pre-Columbian societies,” says Levis. And he adds: “These archaeological sites are evidence that indigenous communities have mastered sophisticated land and crop management techniques, which in some cases are still present in current knowledge and practices, and can inspire new ways of living with the forest without its destruction is necessary.” .”
In addition, the research is an important step towards considering the Amazon rainforest not only as a space of biodiversity of animals and plants, but also as a great source of archaeological research. Previously, we were sure that 427 species of mammals, 1,300 species of birds, 378 species of reptiles and more than 400 species of amphibians live in the Amazon basin. Now we know that there are more than 10,000 large earthworks on the surface covered by the forest, which may hold the key to better understanding the customs and culture of the indigenous communities that lived in the jungle for thousands of years.
Luiz Aragão tells EL PAÍS that the map also allows us to demonstrate that in regions with a high probability of finding archaeological sites, the density of domesticated tree species is increasing. “This was an interesting result because it shows that pre-Columbian populations had a very close relationship with species that provided them with well-being, especially food and fiber.” From this we can conclude that they manipulated the ecosystem to increase the density of these In fact, research shows that the number of edible fruit and nut plants and trees has increased significantly in places where archaeological sites are believed to be located. The authors identified relationships between the predicted probability of earthworks and the occurrence and abundance of domesticated tree species and found a significant relationship between the two. “This suggests that active pre-Columbian indigenous forest management practices have long shaped the ecology of modern forests across the Amazon,” the article says.
Figure of the Amazon forest landscape. Diego Lourenco Gurgel
Although the research is new, Aragão cautiously points out its limitations. When asked whether it is possible to conclude that there are more than 10,000 unexplored pre-Columbian archaeological sites in the Amazon, he emphatically answers “yes,” but it is clear that it is an estimate. “Based on the existing number of known structures and our predictive model, we believe that many sites are still hidden under the canopy. Of course, this is an estimate based on statistical methods and is subject to uncertainty. But it is very likely that there are thousands of archaeological sites to discover,” he explains to EL PAÍS.
Hans ter Steege, co-author of the paper and researcher at the Naturalis Biodiversity Center and Utrecht University, explains that these archaeological sites must be concentrated in specific areas of the jungle: “We assume that 90% of the Amazon rainforest is very large “There are few opportunities for Earth to move, so this type of change may have occurred mainly in 10% of its area,” the scientist said in a statement.
Although the size and characteristics of the thousands of archaeological sites in the jungle are not yet precisely known, this work opens new avenues of research so that future scientists have a compass to know where to explore. “Amazon forests deserve protection not only because of their ecological and environmental value, but also because of their high archaeological, social and biocultural value, which can teach modern society how to sustainably manage its natural resources,” the study concludes.
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