Researchers have uncovered evidence of a vast pre-colonial civilisation that flourished across southwestern Amazonia, identifying more than 20,000 monumental earthworks hidden beneath the rainforest canopy.
The new findings, published in Nature, combine the airborne LiDAR surveys with satellite images to reveal that the Aquiry civilisation occupied a much larger area than previously known.
The team conducted more than 4,400 kilometres of airborne LiDAR surveys over the Brazilian states of Acre and Amazonas. The laser-based technology, which can penetrate dense forest canopy, identified 432 earthworks, only 36 of which had previously been recorded.
According to the researchers, there are between 24,000 and 30,000 earthworks and other monumental landscape features, challenging long-held assumptions that the pre-Columbian Amazon was only sparsely populated.
The newly documented monuments include geometric ditched enclosures, embankments and ceremonial complexes dating from around 600 BC to AD 850. Constructed in circular, square and multi-sided forms, the earthworks are thought to have served as ceremonial, political and social centres rather than permanent settlements or defensive structures.
The LiDAR survey identified around five times more earthworks than could be detected using satellite imagery alone, highlighting how much of Amazonia’s archaeological landscape remains concealed beneath dense tropical forest.
However, the authors now estimate the Aquiry civilisation covered about 183,000 square kilometres – three times larger than previous estimates. They also found that the land area could support between 1.25 and 3 million people at its peak between AD 100 and 300.
The findings add to growing evidence that pre-Columbian Amazonia was home to complex societies that actively engineered their environment through agriculture, landscape management and large-scale monument construction, not a wilderness as such.
The study also shows that these communities planted crops like maize, squash, manioc, beans and peanuts and managed economically important tree species like Brazil nut and peach palm. These long-term land use practices may have contributed to the formation and biodiversity of the modern Amazon rainforest.
If similar archaeological landscapes are identified elsewhere in Amazonia, current estimates of the region’s pre-Columbian population—and its impact on rainforest ecology, biodiversity and even climate models—may need to be revised.
The discovery also demonstrates the transformative role of LiDAR in archaeology, revealing extensive cultural landscapes that have remained hidden beneath one of the world’s largest tropical forests for centuries.
Sources : Nature
