UNIVERSITY PARK, Pa. — Archaeological sites like the Great Wall of China and the pyramids can be seen from space, but for ancient societies that did not build, their traces on the landscape are more difficult to find. Now Penn State researchers have used satellite data to identify areas in coastal southwest Madagascar where indigenous foragers altered their surroundings.
“One of the things I’m interested in is exploring the different ways that people leave a footprint on the landscape and understanding how long the traces of that footprint last,” said Dylan S. Davis, graduate student in anthropology, Penn State. “For a small-scale society that doesn’t build structures, how do they impact the landscape, and will that impact last thousands of years?”
Using high-resolution PlanetScope satellite imaging and vegetative indices to show how the landscape co-evolved with humans, and then a random forest algorithm and statistics to quantify the amount that humans changed their surroundings, the researchers were able to identify areas of human alteration. They report their results in Frontiers in Ecology and Evolution.
Archaeologists often looked at agricultural and pastoral societies in the past and catalogued the changes these lifestyles make in the landscape. Permanent or semi-permanent housing, fields and other structures dot the area and, in some places, completely change the natural landscape, but the impact on the landscape of hunter-gatherers is usually confined to temporary living locations and the remains are a few broken pieces of pottery, fire pits or animal bones. The assumption was that these communities did not alter the overall landscape.