Assessing shoreline exposure and oyster habitat suitability maximizes potential success for sustainable shoreline protection using restored oyster reefs

Abstract

Oyster reefs provide valuable ecosystem services that contribute to coastal resilience. Unfortunately, many reefs have been degraded or removed completely, and there are increased efforts to restore oysters in many coastal areas. In particular, much attention has recently been given to the restoration of shellfish reefs along eroding shorelines to reduce erosion. Such fringing reef approaches, however, often lack empirical data to identify locations where reefs are most effective in reducing marsh erosion, or fully take into account habitat suitability. Using monitoring data from 5 separate fringing reef projects across coastal Louisiana, we quantify shoreline exposure (fetch + wind direction + wind speed) and reef impacts on shoreline retreat. Our results indicate that fringing oyster reefs have a higher impact on shoreline retreat at higher exposure shorelines. At higher exposures, fringing reefs reduced marsh edge erosion an average of 1.0 m y−1. Using these data, we identify ranges of shoreline exposure values where oyster reefs are most effective at reducing marsh edge erosion and apply this knowledge to a case study within one Louisiana estuary. In Breton Sound estuary, we calculate shoreline exposure at 500 random points and then overlay a habitat suitability index for oysters. This method and the resulting visualization show areas most likely to support sustainable oyster populations as well as significantly reduce shoreline erosion. Our results demonstrate how site selection criteria, which include shoreline exposure and habitat suitability, are critical to ensuring greater positive impacts and longevity of oyster reef restoration projects.

A global review of the ecosystem services provided by bivalve aquaculture

“…; La Peyre et al . ). Using data from multiple projects over an extended timeframe, La Peyre et al .…”

“…Many waterways suffer from the introduction of heavy shore defences due to the concentrated load upon soft sediments: the results of which can require additional efforts and funds in order to help maintain the breakwater structures (Piazza et al 2005). Oyster reefs, however, act as biological barriers to reduce erosion, and do not require additional upkeep once established (Scyphers et al 2011;La Peyre et al 2015). Using data from multiple projects over an extended timeframe, La Peyre et al (2015) found that oyster reefs reduced marsh retreat by an average of 1 m yr À1 along moderately exposed and highly exposed shores.…”

“…Oyster reefs, however, act as biological barriers to reduce erosion, and do not require additional upkeep once established (Scyphers et al 2011;La Peyre et al 2015). Using data from multiple projects over an extended timeframe, La Peyre et al (2015) found that oyster reefs reduced marsh retreat by an average of 1 m yr À1 along moderately exposed and highly exposed shores. Location of the oyster reef barriers was crucial for ensuring their effectiveness, the oyster reefs requiring circulation currents suitable for larval recruitment and adequate water quality (Coen & Luckenbach 2000).…”

“…Location of the oyster reef barriers was crucial for ensuring their effectiveness, the oyster reefs requiring circulation currents suitable for larval recruitment and adequate water quality (Coen & Luckenbach 2000). While marshland retreat was not stopped, the rate of erosion was reduced (La Peyre et al 2015).…”

The application of oyster reefs in shoreline protection: Are we over‐engineering for an ecosystem engineer?

“…Therefore, the objectives of ecological research on oyster reef living shorelines should focus on the factors that affect the persistence of oysters on the reef structure ( predict the locations for successful oyster growth and oyster reef living shorelines (e.g. Fuchs & Reidenbach, 2013;La Peyre et al, 2015).…”