Overview
- The Nature paper, which published Wednesday, presents airborne LiDAR mapping of roughly 4,497 square kilometers that identified 432 earthworks in Brazil’s Acre and Amazonas states, 396 of them previously unknown.
- Authors extrapolate the survey data to propose between about 24,000 and 30,000 earthworks across southwestern Amazonia and estimate a peak Aquiry population of roughly 1.25 million to 3 million people.
- The mapped features are geometric ditched enclosures and raised embankments linked by straight roads, which the team interprets as ceremonial and political centers active from about 600 BCE to 850 CE with a peak around CE 100–300.
- If representative more widely, the finds imply long-term forest management and agriculture — including maize, manioc, squash and managed Brazil-nut and palm groves — with possible consequences for regional biodiversity and carbon calculations, but experts warn the extrapolations depend on sampling, site counts and contemporaneity.
- Researchers and commentators say the next steps are expanded LiDAR coverage, targeted ground-truthing through excavation and radiocarbon dating, and interdisciplinary study to confirm the scale and human impact the paper proposes.