Researchers at Baylor University say sediment studies in pre-European floodplains, long thought to be completely natural in origin, showed a history of impact from prehistoric indigenous land use, proving colonial-era Europeans were not the first people to have an impact on the hydrologic systems of eastern North America, a university release said Monday.
Researchers had previously thought early colonial land-use practices such as deforestation, plowing and damming had influenced present-day hydrological systems across eastern North America.
However, prehistoric small-scale agricultural societies had already caused widespread ecological change, the Baylor study found.
"The findings conclusively demonstrate that Native Americans in eastern North America impacted their environment well before the arrival of Europeans," researcher Gary Stinchcomb said.
Prehistoric people practiced deforestation to reorient their settlements and intensify corn production, leading to increased sedimentation in the valley bottoms, the researchers say.
"Through their agricultural practices, Native Americans increased soil erosion and sediment yields to the Delaware River basin," Stinchcomb said.