Increasingly, regulatory agencies and restoration scientists are advocating for more innovative approaches, such as Living Shorelines (LSs) techniques, as a form of resilient shoreline stabilization to protecting fragile coastal ecosystems. One popular type of LS is the restoration of fringe salt marsh habitat with the inclusion of a riprap sill at the low marsh edge. While LSs are growing in use, there is relatively little empirical data supporting its efficacy in New England. We designed a BACI study for the first three LSs constructed in New Hampshire to compare short-term restoration dynamics (< 5 years) to local reference marshes and degraded pre-restoration shorelines. We hypothesized the LSs would possess greater habitat structure than the degraded shorelines yet would lag in proper vegetation cover, invertebrate communities, and porewater chemistry of local references several years post-restoration. Vegetation and macroinvertebrate communities and porewater chemistry were plot sampled in August and September of 2019. The Restoration Performance Index (RPI) will quantify the restoration performance of the LSs by converting biotic and abiotic metrics to an objective, relative score compared to both the reference and pre-restoration shorelines. The construction of the LSs immediately improved existing salt marsh habitat with greater halophyte cover and halophyte richness compared to degraded shorelines. The LSs still require more time to reach local reference conditions seen in lower halophyte percent cover and invertebrate density and positive soil reduction-oxidation potential values. Further analysis will calculate the scores of the RPI to evaluate explanatory factors and set expectations for future LS projects.
