Background/Question/Methods Monotypic stands of Juncus roemerianus dominate the marshes of Mississippi and other areas in the northeastern Gulf of Mexico. Although Juncus-dominated marshes are common in this region, few studies examined the effects of restoration efforts on faunal inhabitants of these marsh ecosystems. Deer Island is a remnant island off the coast of Biloxi, Mississippi and has been subject to erosion and morphological changes since the 1850s resulting in a loss of one third its original footprint. The United States Army Corps of Engineers and Mississippi Department of Marine Resources have conducted restoration with beneficial use material since 2003 to restore the Juncus-dominated landscape to enhance ecological functions such carbon sequestration and fisheries support. To assess the outcome of these restoration efforts, this study examined environmental characteristics, faunal community structure, and trophic support in two restored marshes (5+ yrs old and 15+ yrs old) and a natural reference marsh (100+ yrs old). Results/Conclusions Microbial diversity assessment in fall 2016 discovered that plants from the restored and reference areas supported similar microbial diversity indicating the rapid colonization of planted grasses with indigenous soil microbiota. Although close in composition, the microbial communities from the three studied sites differed significantly in the relative abundance of specific taxa. Sampling in Spring and Fall 2017 through 2019 demonstrated establishment of planted salt marsh and naturally-recruited sand-berm vegetation. Transect sampling assessed the vascular plant community diversity and biomass, as well as relating these parameters to geomorphological characteristics of the area by measuring elevation and soil condition. The two constructed sites were found to have a diverse array of vegetation, but function of the salt marsh in terms of root production and sediment organic carbon deposition remained underdeveloped when compared to the natural reference site. Transect sampling targeted invertebrate abundances along the transects which found to be were significantly higher in the natural marsh. Nekton abundance, species richness, and Simpson’s index of diversity varied by site and season. Stable isotope analysis (SIA) provided additional insight as to whether Juncus is a primary carbon source and how energy is transferred through consumers in the restored marshes compared to the natural marsh. Multiple trophic levels were investigated and restoration trajectory towards natural marsh condition was found to inadequate even after 10 years of recovery. Below-ground and litter processes in particular showed that longer time is needed to restore these areas to full natural equivalence.
