Response of stressed marsh following Hurricane Irma

Presentation given at the Georgia Water Resources Council.

Salt marshes buffer developed coastal areas from storm surge produced by large storm events, like Hurricane Irma. Salt marshes have also been experiencing dieback events, leading to large mudflats, which erode, lose elevation, and impede marsh recovery. We have been monitoring vegetation, soil, groundwater, and dieback boundaries at a dieback site near St. Simons Island, GA, since 2014. The dieback was recovering before Hurricane Irma, which impacted the area in September 2017. Following the hurricane, once healthy Spartina alterniflora on the platform and upland boarder vegetation became stressed, most-likely from elevated salinities and storm surge flooding. New dieback along the creek bank also appeared. Periodic monitoring of the site in the months following the hurricane has shown that the upland boarder vegetation and new dieback along the creek bank have largely recovered. The existing dieback on the platform has continued to recover, however; the stressed S. alterniflora has remained stressed. Overall, we find that the marsh is generally resilient, with most areas of the marsh returning to pre-hurricane conditions within one year following the hurricane.