Estuarine and Coastal Structures: Environmental Effects and a Focus on Shore and Nearshore Structures

Rapidly growing populations and expanding development are intensifying pressures on coastal ecosystems. Sea-level rise and other predicted effects of climate change are expected to exert even greater pressures on coastal ecosystems, exacerbating erosion, degrading habitat, and accelerating shoreline retreat. Historically, society’s responses to threats from erosion and shoreline retreat have relied on armoring and other engineered coastal defenses, although, more recently, there has been increasing emphasis on biologically softening armored shorelines using green infrastructure, nature-based and living shoreline approaches. Despite widespread use on all types of shorelines, information regarding the scale of ecological impacts of shoreline armoring continues to be quite limited relative to the number and extent of new structures proposed globally. Here, we summarize existing knowledge on the effects of armoring structures on the biodiversity, productivity, structure, and function of coastal ecosystems.