Abstract or Summary
Ribbed mussels are the functional dominant species in eastern U.S. salt marshes, providing particulate nutrient filtration and enhanced vegetative growth services. Wetland loss in the Delaware Estuary has resulted in ribbed mussel population declines and increased interest in ecological restoration practices, such as living shorelines. Incorporation of ribbed mussels into restoration applications represents an opportunity to enhance ecological structure and function in shoreline stabilization projects. Since 2008, the Partnership for the Delaware Estuary has implemented 14 living shorelines, with ribbed mussel recruitment exhibiting temporal and spatial variability. To better understand sources of this variability, a three-tiered study was employed to evaluate differences in ribbed mussel recruitment: (1) on previously deployed substrates (2009–10); (2) on exposed vs. protected surfaces; and (3) across a variety of substrates. Results showed that on aged living shorelines, ribbed mussel density was greater on oyster shell bags than on coir fiber logs and the unaltered marsh edge. On newly deployed experimental materials, recruitment was higher on the surface of shell bags when protected by mesh but was only ,8% of total bag recruitment and did not differ between protected and unprotected shell bags. Mussel recruitment was greater on oyster shell and Oyster Castlet than on coir fiber recruitment tiles, and also on those protected by shell bag mesh than by coir fiber or without protection. Therefore, living shorelines that incorporate ribbed mussel refuge in the form of protected surfaces and interstitial space can facilitate recruitment and persistence, enhancing populations and their associated water quality services.