The NCNERR contributed to a national-level research project focusing on using relatively undisturbed tidal wetland sites at or near five National Estuarine Research Reserves as reference sites for comparison with 17 local wetland restoration projects in various stages of project completion and succession.
The study, which was funded by the NOAA Restoration Center, was guided by four main objectives:
- Determine the level of restoration achieved at each project restoration site
- Identify key biotic (vegetation) and abiotic (hydrology, soils, marsh elevation) indicators that best explain variation in restoration response
- Determine the utility of long-term wetland monitoring sites at Reserves as reference sites for restoration projects implemented within the region
- Compare responses of hydrologic and excavation/fill types of restoration
Each study area was monitored from 2008-2010 and evaluated using the Restoration Performance Index (RPI) to compare user-selected variables among Reserve tidal wetlands and restored tidal wetlands. Key findings and recommendations from this project included:
- Reserve tidal wetland sites can provide appropriate long-term reference sites for local tidal wetland restoration projects.
- A recently formalized ecological index, the RPI, which compares change in user-selected indicator variables over time between reference and restoration sites, offers promise as an effective trajectory analysis strategy for measuring restoration status.
- According to RPI values, most restoration projects surveyed in this study appeared to have achieved an intermediate level of restoration with two sites appearing to have become very similar to their paired reference sites, suggesting a high level of restoration.
- Two abiotic variables – 1) elevation of marsh platform, and 2) depth to groundwater were significantly correlated with plant community structure, providing important indicators of tidal wetland restoration performance.
Final NERRS Report
North Carolina Site Research
The Rachel Carson, Masonboro Island, and Zeke's Island NCNERR components were selected for long-term monitoring related to the national research project. As a region encompassing two biogeographical zones and a range of coastal conditions, lessons learned from restoration analysis and comparison in North Carolina have wide applicability along the U.S. East Coast.