CLIMATE CHANGE DRIVEN GROUNDWATER SALINIZATION AND TREE MORTALITY

Sapelo Island, a barrier island off the coast of Georgia, USA, is a protected area under the United States Department of Natural Resources. Its sparse population and minimal development have preserved its rich biodiversity and ecological significance. Over the past decade, however, an increase in tree mortality has been noted across the island. Given its ecological importance, identifying the cause of this tree mortality is crucial. This study explored saltwater intrusion as a potential factor contributing to this issue. We employed electrical resistivity, in situ groundwater monitoring, and visual assessments to map and monitor subsurface saltwater intrusion at three distinct sites on Sapelo Island. The preliminary findings indicate that despite the limited number of pumping wells, the island is experiencing subsurface saltwater intrusion, particularly during high tide events. Furthermore, there is a positive correlation between heightened salinity levels and tree mortality. This saline incursion is prompting an ecological transition, with grasses gradually replacing trees—a trend that is likely occurring in similar locations across the globe.