Marsh Restoration: Ribbed Mussels (Geukensia demissa) as a Revival Mechanism to Rebuild the Coastal Salt Marshes of Long Island, New York

Hurricane severity and frequency have been exacerbated by 190 years of anthropogenic climate change. In 2012, Superstorm Sandy decimated Long Island, a 190-kilometer-long island in southeast New York, with up to 4 meters of saltwater inundation due to storm surge, resulting in the highest levels of destruction since the 1938 “Long Island Express.” Sandy was the fifth most costly hurricane on record, after Katrina in 2005, and Harvey, Maria, and Irma in 2017. Synthetic storm-surge barriers such as concrete-and-steel tidal gates are exorbitantly costly to construct and decrease biodiversity by barring habitat expansion. Natural storm barriers, termed “living shorelines,” have recently been suggested as an alternative, owing to their structurally resilient and regenerative properties. Coastal marshes, one type of natural barrier, are key to holding back storm surge; however, the contiguous United States lost coastal wetlands at 0.15 percent per year from 1998 through 2009, the final year for which the data were available. This study investigated ribbed mussels (Geukensia demissa) as a potential regenerative component of living shorelines. Transects and environmental energetic measurements were applied to draw conclusions between mussel abundance and scarcity and coastline erosion in the waters off Freeport, Long Island. It was discerned that the current rate of marsh disintegration on Long Island is 6.5 to 20 times greater than the national rate, as last measured a decade ago, and certain Long Island regions are projected to lose all coastal wetlands by 2079.

Facilitation between ecosystem engineers, salt marsh grass and mussels, produces pattern formation on salt marsh shorelines

Interspecific facilitation between ecosystem engineers, such as salt marsh grass and mussel aggregations, is a key process that structures communities and enhances biodiversity. Scale-dependent pattern formation via self-organization is ubiquitous in terrestrial, aquatic and marine ecosystems. Despite their prevalence and ecological importance, these two phenomena have rarely been linked. We provide empirical evidence that the facilitative interaction in salt marshes between smooth cordgrass Spartina alterniflora and the ribbed mussel Geukensia demissa produces distinct spatial patterns along marsh shorelines. These findings advance our understanding of linkages between facilitation and pattern formation in nature, and are particularly relevant to conservation and restoration of salt marshes threatened by climate change and sea-level rise.