Response of Nekton to Tidal Salt Marsh Restoration, a Meta-Analysis of Restoration Trajectories

Abstract

Restoration of 4049 ha of tidal wetlands was required to offset nekton losses at a power facility located on Delaware Bay, USA. Vegetation coverage, the permitted criterion for success, was compared by meta-analysis to restoration trajectories for abundance and growth of dominant nekton during the same 17-year period at two reference and five restoration sites. Mean catch per unit effort (CPUE), at both upper Bay (former Phragmites australis dominated sites) and lower Bay (former salt hay farms), were generally indistinguishable from those of the reference sites, and Hedge’s d for all sites suggested that numbers of individuals at restored locations did not differ significantly from those at the reference sites. Mean length distributions of dominant nekton in the upper Bay, however, were negative for all restoration sites combined by the end of the study. Although growth of nekton at the lower Bay restoration sites was indistinguishable from reference sites, the grand mean length for nekton measured at all sites in the Bay was negative suggesting that nekton growth at the formerly Phragmites-dominated sites failed to meet the restoration goals by the end of the study period. Thus, vegetation success criteria may not necessarily reflect recovery of animal related success criteria.