Gigliotti: Testing the Efficacy of Saltmarsh Restoration

Testing the Efficacy of Saltmarsh Restoration for a Globally Endangered Species

Franco Gigliotti, Chris Elphick

Saltmarsh ecosystems are changing, with evidence of marsh loss as sea levels rise. Breeding bird species, including the saltmarsh sparrow Ammospiza caudacuta, that depend on these ecosystems are likewise declining. Restoration will be a necessary component of conservation for these species, and thin layer placement of sediment (TLP) has garnered interest as a restoration tool. Saltmarsh sparrows require high-elevation marsh habitat for breeding, but benefits of restoration will only be realized if TLP restored marsh generates nesting habitat and restoration does not negatively impact nest success. We worked with Stewart B McKinney NWR, Audubon Connecticut, and other partners to assess impacts of TLP on saltmarsh sparrows using constructed TLP hummocks (n=14) each with multiple vegetation treatments (n=5) at Great Meadows Marsh (GMM). Preliminary results indicate that (1) sparrows nesting in unrestored areas at GMM and at a reference site both exhibited high rates of nest failure, (2) hummocks achieved target elevations to promote marsh plant regeneration, and (3) initial vegetation growth on hummocks varied by treatment. These results indicate baseline hummock conditions following sediment addition. Data in subsequent years will inform saltmarsh sparrow nest success, nest site selection, and space use following TLP, enhancing understanding of the efficacy of TLP to reduce nest failure, a main cause of decline for this threatened species.: