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Living Shorelines in Chesapeake Bay Improve Benthic Communities

[a] Before-after control-impact [BACI] study locations in the upper (Windy Hill) and lower (Lynnhaven) Chesapeake Bay, USA. At Windy Hill: [b] aerial view of the living shoreline just after construction and [c] a shoreline view showing marsh grass growth after 15 months (foreground) and the northernmost breakwater sill (background); photo credits, Chesapeake & Coastal Service, Maryland Department of Natural Resources. At Lynnhaven: [d] the construction of the living shoreline and placement of sand fill and [e] the living shoreline with 10 months of marsh growth. Credit: D. Stephan
A new NCCOS-funded study tracked the effects of living shoreline construction on benthic (bottom-dwelling) invertebrate animal communities in Chesapeake Bay. Coastal erosion and sea level rise have led to increased interest and demand for living shorelines, which incorporate plants and natural materials to stabilize marsh land, over traditional shoreline armoring, like bulkheads. However, few studies have evaluated the ecosystem services provided by living shoreline projects.

Scientists compared annual samples of bottom-dwelling fauna at two study sites – one where a living shoreline replaced an existing bulkhead, and one where stabilization via a living shoreline was newly established – for three years.

In general, overall results suggested that living shorelines changed the benthic communities that previously had a bulkhead to more closely resemble those in adjacent marshes with no bulkhead, increasing the density and biomass of clams by the second year. Bivalves, like these clams, can be a strong indicator of a healthy ecosystem, further suggesting the benefits of living shorelines. The density and biomass of polychaete worms declined at first, but appeared to begin increasing again by the end of the study.

Overall, the project highlights the benefit of preventing erosion with living shorelines to benthic communities over traditional shoreline hardening techniques.  Ultimately longer-term studies are recommended to identify all of the benefits of livening shorelines.

Learn about other NCCOS work on living shorelines here.

March 2018 feature in Coastal & Estuarine Science News (CESN)

Citation:: Davenport, T.M., R.D. Seitz, K.E. Knick, and N. Jackson. 2018. Living shorelines support near-shore benthic communities in upper and lower Chesapeake Bay. Estuaries and Coasts. doi: 10.1007/s12237-017-0361-8

For more information, contact Elizabeth.Turner@noaa.gov.