Abstract
Increasingly, coastal wetland restoration is utilized to offset wetland loss and degradation and to recover ecosystem services, making it important to evaluate the relative effectiveness and times to functional equivalence of different restoration strategies. Two critically important services provided by coastal wetlands are carbon storage and nitrogen removal. By restoring or creating wetlands, it is possible to recover these functions and services, thereby promoting more resilient coastal watersheds. As part of a new Mississippi-Alabama Sea Grant project, we will evaluate ecosystem structure and function in habitat restoration and creation projects of different ages. Our objectives are to compare structural and functional attributes in restored coastal wetlands of different ages to reference wetlands, to estimate recovery trajectories and times to equivalency for these attributes, and to evaluate the relative effectiveness of different habitat restoration projects. We will inventory plant community structure, plant biomass, soil carbon storage, and nitrogen removal capacity via denitrification in 16 coastal wetlands, including 12 created or restored wetlands ranging in age from 4 to 33 years. Preliminary results from one reference and two 33-year-old created marshes revealed that plant biomass stocks, soil organic matter, and litter decomposition rates were greater in the reference marsh than two constructed marshes, with the natural marsh storing approximately ten times more carbon than constructed marshes. Further, denitrification was two times greater in the natural marsh than one of the two constructed marshes. Through similar analyses at all sites, we will assess the relative effectiveness of different habitat restoration projects along the Mississippi-Alabama Gulf Coast, which will be used to inform restoration practices. Thus, this project will provide important baseline information about restoration activities, while also assessing the structural and functional outcomes of projects that used different approaches for wetland restoration or creation.
