CRMS uses a multiple reference approach to biological monitoring and uses aspects of hydrogeomorphic functional assessments and probabilistic sampling that address the limited effectiveness of the traditional paired-reference monitoring approach in Louisiana.
This approach includes a suite of sites that encompass the range of ecological conditions for each stratum, with projects placed on a continuum of conditions found for that stratum. Trajectories in reference sites are then compared with project trajectories through time. The approach could serve as a model for evaluating wetland ecosystems.
In 1990, the U.S. Congress enacted the Coastal Wetlands Planning, Protection and Restoration Act (CWPPRA) in response to the growing awareness of Louisiana’s land loss crisis. The CWPPRA was the first Federal, statutorily mandated program with a stable source of funds dedicated exclusively to the short- and long-term restoration of the coastal wetlands of Louisiana. To date, 204 restoration projects have been constructed through the CWPPRA program. These projects include diversions of freshwater and sediments to improve marsh vegetation; dredged material placement for marsh creation; shoreline protection; sediment and nutrient trapping; hydrologic restoration through outfall, marsh, and delta management; and vegetation planting on barrier islands.
In 2003, the CWPPRA Task Force and the Louisiana State Wetlands Authority adopted the “Coastwide Reference Monitoring System – Wetlands” (CRMS–Wetlands) for Louisiana as a mechanism to monitor and evaluate the effectiveness of CWPPRA projects at the project, region, and coastwide levels.
In 1990, the U.S. Congress enacted the Coastal Wetlands Planning, Protection and Restoration Act (CWPPRA) in response to the growing awareness of Louisiana’s land loss crisis. The CWPPRA was the first Federal, statutorily mandated program with a sta
CRMS site selection, which is described in Steyer and others (2003), was made from a historical database of stations spanning the entire coast of Louisiana, encompassing each of the nine hydrologic basins and all five marsh types (fresh, intermediate, brackish, saline, and swamp). The resampling methodology utilized in Steyer and others (2003) indicated that 100 randomly selected reference sites would accurately represent the true composition of coastwide vegetation at a 95 percent confidence level. However, in order to detect a 20 percent change in coastal marsh vegetation between two time periods, at least 80 percent of the time, approximately 400 reference sites were needed. Because of land rights and other technical issues, 390 sites with a fixed annual sampling design were approved and secured for CRMS data collection. These 390 CRMS sites are located within nine coastal basins and four CWPPRA regions, covering the entire Louisiana coast. Site construction and data collection began in 2005.
At each of the 390 CRMS sites the same suite of ecological variables are collected at intervals specific to each data type. These variables include vegetation species composition and percent cover; hourly water elevation, salinity and temperature; surface elevation change and vertical accretion; soil properties; and land to water ratios. Site establishment and data collection methodology are described in Folse and others (2014).