Amazon Rainforest Was Shaped By An Ancient Hunger For Fruits And Nuts

“It’s not enough to study the environmental conditions that structure these communities of trees and palms,” says Carolina Levis, a palaeoecologist at Wageningen University in the Netherlands and the lead author of the study. “We need to ask ‘what are the human influences in these communities?’”

A cornucopia

The researchers wanted to know whether this was because of human influence or the environment. So they compared the distribution of domesticated species to more than 3,000 known pre-Columbian archaeological sites and likely settlement areas, including near the banks of rivers. Domesticated species were much more likely to thrive where ancient people had lived than were non-domesticated species.

Old versus new

This doesn’t necessarily mean that ancient human actions were solely responsible for the distribution of domesticated plants, cautions Crystal McMichael, a palaeoecologist at the University of Amsterdam. “It’s quite well known that ancient people and modern people both settle in similar areas.” So it’s possible that more modern groups influenced the ecosystems we see today as much as ancient ones, she adds.

Human actions could also have created conditions that favoured domesticated plants over their wild brethren, says Mark Bush, an ecologist at the Florida Institute of Technology in Melbourne. And the domesticated species could re-colonize disturbed areas more easily than non-domesticated ones without any help from people.

When people abandoned Mayan sites in Central America, Brosimum trees re-colonized the area. But for years, researchers thought the Mayans had planted them deliberately. Levis and her team could be observing a similar phenomenon, Bush says.

“People want to preserve pristine forests for conservation and to preserve life,” she says. “But if this is true, if people enriched the forests by domesticating palms, that is also a cultural artefact.” The trees that live in these populated areas may be relics of a vibrant past.

This article is reproduced with permission and was first published on March 2, 2017.