There was a time when no archaeologist wanted to discover such a complex settlement in this relatively resource-poor part of the rainforest. In an article published in the journal Nature Communications on Tuesday, de Souza and his colleagues describe the hill village and 80 other newly discovered archaeological sites dating from 1250-1500.
They predict that the area will have hundreds more undiscovered Places hid as many as a million people had carefully managed the rainforest long before the arrival of Europeans.
"It's an important piece of paper," said Dolores Piperno, an archaeobotanist at the National Museum of Natural History who has worked extensively on the Amazon, was not involved in the new study. Although unconvinced of de Souza's conclusions about the size of the region's pre-Columbian population, the discoveries are adding to a growing body of evidence that large communities thrived in one of the world's most diverse landscapes.
Fifty years ago, she said, "prominent scholars thought that little of cultural significance had ever been done in a tropical forest, it was too overgrown, too humid, and the result of these beliefs was that people never saw the forests They were alleged to have been "a kind of noble savage," she said.
"But these views have been overturned," continued Piperno. "Tropical forests played an important role in agriculture as well." [DeSouzaaresearcherattheUniversityofExeterinEnglandidentifiedthenewarchaeologicalsiteswithsatelliteimagesoftheUpperTapajóBasinattheBrazilianborderwithBoliviaincollaborationwithscientistsfromtheUnitedKingdomandBrazilwheretherainissparseandmoreseasonalandtherainforestchangesintoasavannah-likeecosystemasthebasinisfarawayfromtheoverflowResearchershaveoverlookeditforalongtimedeSouzasaidassumingthatitcouldnotsupportlargegroupsofpeople
But the aerial photographs revealed dozens of geometric geoglyphic trenches carved into the earth. Although the locations vary in shape and size ̵
De Souza and his co-workers spent a month conducting at the university – basic surveys of 24 of these sites. They contained all the evidence that they were inhabited: abandoned stone tools and broken ceramics, buried garbage dumps, an enriched soil called Terra Preta, which is characteristic of natives' nourishment by burning and fertilizing. By measuring how much radioactive carbon from the samples was mined over the years, the researchers dated charcoal found at the sites in the early and mid-fifteenth centuries.
Since the 1970s, scientists have identified large, ingenious geoglyphs of the Amazon. Some have estimated that there are about 60,000 square kilometers of Terra Preta in the basin. Other research has shown that entire regions of the rainforest are dominated by tree species that were once cultivated by indigenous peoples for food. And on both sides of the region studied by de Souza, highly planned networks of villages were identified.
The latest discovery, according to de Souza, suggests that there was an uninterrupted series of settlements along the entire southern edge of the Amazon basin  "It seems that it was a mosaic of cultures," he continued. The villages shared some practices – they enriched the soil, planted Brazil nut trees and cocoa, circled their homes with moats – but spoke a variety of languages.
They included their findings in models predicting population densities, de Souza and his colleagues estimated that between 500,000 and one million people lived in this part of the Amazon and built between 1,000 and 1,500 enclosures.
Piperno was skeptical that the region's pre-Columbian population was really that large, pointing out earlier studies that showed fewer people were needed to build this earthwork than previously believed.
De Souza agreed that there is much more work to do. He and his colleagues plan to dig out the Boa Vista website and conduct surveys to find more settlements.
"It is likely that some areas of the Amazon support large populations and others are not," he said. "Because there is so little research, we are slowly discovering what's going on in everyone."
These discoveries not only affect our understanding of the past; They have an impact on the future. Huge parts of the Amazon are lost through deforestation, land clearance for agriculture, forest fires, dams, mining and other forms of habitat destruction. The ability of the rainforest to function as "the lungs of the world" by inhaling carbon dioxide is declining.
Although conservationists often speak of a "pristine" landscape, studies by de Souza and others suggest that Aboriginal people have influenced and enriched the rainforest for hundreds of years. If we want to preserve the Amazon, researchers say, we need to take these effects into account.
"The forest is an artifact of modification," said de Souza. He quickly added, "It has nothing to do with the kind of practice we see today – large-scale, cleansing monoculture – these people have combined small-scale farming with the management of useful tree species, so it was more of a sustainable type of land use . "
Author Information: Sarah Kaplan reports on the strange and wonderful world of science with a focus on new discoveries in paleontology and astronomy.