Sentinel Monitoring of Salt Marshes in the North Carolina National Estuarine Research Reserve
The North Carolina National Estuarine Research Reserve (NERR), along with several other NERRs, acts as a sentinel site to monitor climate change impacts. The reserve is engaged in several long-term ecological monitoring programs to determine the effects of sea level rise, saltwater intrusion, warmer temperatures, shoreline erosion, and coastal storms on species and habitats.
The four sites of the North Carolina NERR—Currituck Banks, Zeke’s Island, Masonboro Island, and Rachel Carson—are comprised of marsh, beach, dune, and maritime forest habitat. Key management issues for these sites include water quality concerns, invasive species, erosion, atmospheric deposition, coastal storms, and sea level rise. Salt marshes, found at Zeke’s Island, Masonboro Island, and the Rachel Carson sites (Currituck Banks has brackish marshes), provide valuable habitat for fish, crabs, and other wildlife, and important ecosystem services by filtering water and protecting shorelines during strong coastal storms. Salt marshes at these sites are threatened by climate change; impacts of concern include sea level rise, warmer temperatures, coastal storms, salinity intrusion, and erosion.
The North Carolina NERR was part of a national effort, created in 2007, to establish salt marshes as long-term reference sites at five reserves (Narragansett; Wells, Maine; Chesapeake Bay, Virginia; North Carolina; South Slough, Oregon) to compare marsh restoration success. Additionally, the reserve, along with other NERRs, participates in the System Wide Monitoring Program (SWMP), tracking changes in water quality, plants, animals, and habitats within the reserve over time. SWMP provides real-time NERR data and allows users to compare variables between reserves over different time periods.
The NERR System and NOAA Restoration Center partnered on a project—created in 2007—to establish salt marshes as long-term reference sites at five reserves (Narragansett; Wells, Maine; Chesapeake Bay, Virginia; North Carolina; South Slough, Oregon). The project was funded through the National Oceanic and Atmospheric Association to 1) use natural marshes as references to understand what is happening at restored marshes, and 2) use these natural reference sites to understand how marshes across the United States are responding to the impacts of climate change. The project required the reserves to conduct effectiveness monitoring of 17 Estuary Restoration Act-funded projects at paired restoration and reference sites. The study used a restoration performance index (RPI) to compare different salt marsh characteristics (e.g., salinity, vegetation cover, flow patterns, peat soils) at natural marsh reference sites and recently restored marsh sites over a two-year period (2008–2010) to track water levels and marsh height in order to determine if and how salt marshes can respond to environmental changes, including sea level rise. The North Carolina NERR compared results between one reference site (Middle Marsh) and three restoration sites (Duke Marine Lab, NC Maritime Museum, Pine Knoll Shores). The study determined that the restoration of hydrologic processes across the five NERRs were quite high while biological processes (e.g., species density, vegetation composition) varied as coastal marsh plant community development may lag in recovery (see Evaluating Tidal Wetland Restoration Performance Using National Estuarine Research Reserve System Reference Sites and the Restoration Performance Index).
Through monitoring over the years, studies on marshes within the reserve have provided valuable insight into the ecosystem’s role in climate adaptation. Starting in 2008, a five-year study was conducted at the Rachel Carson site to quantify the effects of bulkheads—the most common type of shore stabilization method used in North Carolina—and to experiment with the construction of living shorelines as alternatives. The study determined that living shorelines comprised of oyster sills combined with marsh plantings are viable shore stabilization alternatives. In addition, the reserve published a handbook for state estuarine property owners titled “Weighing your Options.” The handbook serves as a tool for landowners seeking to control shoreline erosion.
In addition to research, the North Carolina NERR has placed a significant amount of effort into education, coastal training, and stewardship efforts to ensure public awareness of the value of estuarine systems. Public field trips to reserve sites are offered along with coastal training programs designed for coastal managers to ensure that development decisions are made with the conservation of coastal resources in mind.
Outcomes and Conclusions
In general, NERRs can be particularly useful as long-term reference sites in a changing climate as they are protected areas that undergo regular long-term monitoring of environmental changes. The data collected may be used to inform other restoration efforts and coastal management.
Evaluating Tidal Wetland Restoration Performance Using National Estuarine Research Reserve System Reference Sites and the Restoration Performance Index (RPI)
Weighing Your Options: How to Protect Your Property from Shoreline Erosion
National Estuarine Research Reserve System-Wide Monitoring Program Data
Estuarine Shoreline Stabilization
North Carolina Coastal Reserve and National Estuarine Research Reserve Field Guide
Gregg, R. M. and J. Sheldon. (2021). Sentinel Monitoring of Salt Marshes in the North Carolina National Estuarine Research Reserve[Case study on a project of the North Carolina National Estuarine Research Reserve]. Version 2.0. Product of EcoAdapt's State of Adaptation Program. (Last updated January 2021)