Evaluating Tidal Wetland Restoration Performance Using National Estuarine Research Reserve System Reference Sites and the Restoration Performance Index (RPI)

• Published in: Estuaries and coasts Vol. 41; no. 1; pp. 36 - 51
• Main Authors: Raposa, Kenneth B., Lerberg, Scott, Cornu, Craig, Fear, John, Garfield, Nina, Peter, Christopher, Weber, Robin L.J., Moore, Gregg, Burdick, David, Dionne, Michelle
• Format: Journal Article
• Language: English
• Published: New York Springer Science+Business Media 01.01.2018; Springer US; Springer Nature B.V
• Subjects: Brackishwater environment; Coastal Sciences; Community structure; Dredging; Earth and Environmental Science; Ecological monitoring; Ecology; Environment; Environmental Management; Environmental restoration; Estuaries; Estuarine environments; Excavation; Freshwater & Marine Ecology; Groundwater; Groundwater levels; Hydrology; Parameter identification; Parameters; Performance indices; Restoration; SPECIAL SECTION: THE NATIONAL ESTUARINE RESEARCH RESERVE SYSTEM: AN INTEGRATED NETWORK OF RESEARCH AND MONITORING SITES SUPPORTING COASTAL ZONE MANAGEMENT; Tidal energy; Tidal power; Trajectory analysis; Water and Health; Wetland restoration; Wetlands; Excavation; Elevation; Vegetation monitoring; Reference network; Hydrologic restoration; NERR biomonitoring
• ISSN: 1559-2723; 1559-2731
• DOI: 10.1007/s12237-017-0220-7

Evaluations of tidal wetland restoration efforts suffer from a lack of appropriate reference sites and standardized methods among projects. To help address these issues, the National Estuarine Research Reserve System (NERRS) and the NOAA Restoration Center engaged in a partnership to monitor ecological responses and evaluate 17 tidal wetland restoration projects associated with five reserves. The goals of this study were to (1) determine the level of restoration achieved at each project using the restoration performance index (RPI), which compares change in parameters over time between reference and restoration sites, (2) compare hydrologie and excavation restoration projects using the RPI, (3) identify key indicator parameters for assessing restoration effectiveness, and (4) evaluate the value of the NERRS as reference sites for local restoration projects. We found that the RPI, modified for this study, was an effective tool for evaluating relative differences in restoration performance; most projects achieved an intermediate level of restoration from 2008 to 2010, and two sites became very similar to their paired reference sites, indicating that the restoration efforts were highly effective. There were no differences in RPI scores between hydrologie and excavation restoration project types. Two abiotic parameters (marsh platform elevation and groundwater level) were significantly correlated with vegetation community structure and thus can potentially influence restoration performance. Our results highlight the value of the NERRS as reference sites for assessing tidal wetland restoration projects and provide improved guidance for scientists and restoration practitioners by highlighting the RPI as a trajectory analysis tool and identifying key monitoring parameters.