Indeed there was! There may have been up to 5 million people that lived in what we now call the Amazon Jungle.
Back before the Spanish and Portuguese, a lot of that land was farm land.
From my studies I estimate in South America there was ten times the population the official narrative states. Just the amount of salt being mined alone indicates a demand ten times larger. And humans don’t mine just for kicks, they will only work as hard as it takes to fill an immediate demand.