Mapping past salt marsh dieback in South Carolina's North Inlet-Winyah Bay National Estuarine Research Reserve using remote sensing

: Brown marsh, or marsh dieback, occurs when portions of salt marsh either thin in vegetation, or completely die. The exact extent and locations of marsh dieback are often unknown due to the difficulty accessing salt marshes for in-field observations. Remote sensing provides a synoptic view of Earth surfaces and can help highlight vegetation thinning or loss in large spatial extents. In 2002-2003 there was a marsh dieback event that affected South Carolina. While most research centered on causes of the event, its extent has not been mapped yet. Using satellite data to extract the Normalized Difference Vegetation Index (NDVI) for years 1999 and 2003, this study calculated the change in vegetation greenness within a salt marsh in North Inlet, Georgetown, South Carolina. Results showed where the marsh increased in vegetation and where vegetation was lost/thinned. The northern section of the marsh experienced the most dieback, with the southern end of the mash experienced a gain in vegetation. Though the causes of this dieback event are unknown, there are a few potential causes. The regions of greatest lost often occur with lower marsh elevations and, South Carolina experienced a prolonged extreme drought during 2001. The regions of vegetation loss may be due to the marsh not keeping up with sea level rise, stress from the drought, or a combination of the two.