Before European conquerers arrived, large areas of the Amazon River basin had been cleared away to make room for a network of towns and villages.
The findings raise big questions, says Susanna Hecht of the University of California in Los Angeles.
For starters, it forces a rethink of the long-held assumption that these parts of the Amazon were virtually empty before colonisation. What's more, it shows that the large populations that did inhabit the region transformed the landscape.
"What we find is that what we think of as the primitive Amazon forest is not so primitive after all," Heckenberger told New Scientist. "European colonialism wasted huge numbers of native peoples and cleared them off the land, so that the forest returned."
I'm gonna plug 1491 again...the story above isn't news to anyone who's read this book, which argues that there was plenty going on in the New World before Columbus, et. al. arrived.