Modern coastal ecosystems of the American Southeast are shaped by deep-time human-environment interactions

Coastal and estuarine ecosystems are particularly sensitive to climate change, placing them at the forefront of challenges to mediate impacts of a warming atmosphere, rising sea-levels, and increasingly frequent extreme weather events. To model potential loss, predict and prepare for future regime shifts, or to build effective conservation policies, it is important to understand the long-term socioecological processes that structure modern ecosystems. We highlight how modern ecological baselines along the Georgia coast of eastern North America are shaped by 5000 years of Indigenous and Euro-American land use. We demonstrate the extent and intensity of manifestations of past land use on modern landscapes, especially by way of quantifying the scale of shell deposition by Indigenous communities and the landscape infrastructure of Euro-American plantations. Through both intentional and unintentional impacts, modern estuarine ecosystems globally are products of these engagements, alterations, and creative transformations that we refer to as deep-time legacy drivers. Modern ecological and geomorphological baselines along the Georgia coast of eastern North America are structured by 5000 years of Indigenous and Euro-American interactions with these environments, according to archeology, geomorphology, geology, history, and marine ecology data.