Poster Presentation Freshwater Sciences 2023

Historical changes and contemporary effects: an investigation into the current impacts of remnant hydrological modifications on Sapelo Island, Georgia, United States (#641)

Raymond P. Kidder 1 , Dr. J. Checo Colón-Gaud 1 , Dr. Rachel Guy 2
  1. Biology Department, Georgia Southern University, Statesboro, Georgia, United States
  2. Sapelo Island National Estuarine Research Reserve, Sapleo Island, Georgia, United States

Sapelo Island, Georgia is the fourth largest barrier island on the state’s Atlantic Coast and has a lengthy history of human inhabitation. In the early 18th century, a series of artificial channels were dug to create arable land for plantation-based agriculture. Through the years, this network was extended to drain other areas of the island including the community of Hog Hammock. Though most of the island’s land area outside of Hog Hammock is now owned and managed by the Georgia Department of Natural Resources, the network of ditches and canals is still present. Increased instances of flooding within the community coupled with potential negative impacts to the island’s interior aquatic habitats has led local management staff to question the role of these channels in facilitating saltwater movement within the island. To address these concerns, an effort was undertaken to monitor the hydrology and ecological integrity along the island’s primary artificial channel; Oakdale Creek. A network of passive water parameter sensors was coupled with concurrent leaf-pack deployments and a standardized macroinvertebrate rapid bioassessment protocol to quantify the integrity of the island’s aquatic habitats along the creek. We found that Oakdale Creek facilitated the transport of saline water deep into the island during hurricane events in summer 2022. Macroinvertebrate community compositions varied both spatially along the established salinity gradient as well as seasonally. Decomposition rates and salinity were positively related, though this was likely driven by an increased biomass of available decomposers. The study is still ongoing with hopes to extend data collection through summer of 2024 to account for inter-annual variability. Findings from this research will be used to better inform the management of coastal resources, both human and environmental, in the face of rising sea levels and coastal land loss.