The potential for created oyster shell reefs as a sustainable shoreline protection strategy in Louisiana

Published source details Piazza B.P., Banks P.D., & (2005) The potential for created oyster shell reefs as a sustainable shoreline protection strategy in Louisiana. Restoration Ecology, 13, 499-506.
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This study is summarised as evidence for the following.

	Action	Category
	Build barriers to protect littoral brackish/salt marshes from rising water levels and severe weather Action Link

Build barriers to protect littoral brackish/salt marshes from rising water levels and severe weather

A replicated, randomized, paired, controlled study in 2002–2003 of brackish marsh around a lake in Louisiana, USA (Piazza et al. 2005) found that installing offshore oyster shell reefs reduced the rate of shoreline retreat, but had no significant effect on vegetation cover or biomass within the marshes. Over one year, the rate at which the vegetated shoreline receded was lower for marshes behind oyster shell reefs (8 cm/month) than for unprotected marshes (12 cm/month). Over the year, vegetation cover and above-ground vegetation biomass were statistically similar in marshes behind oyster shell reefs and in unprotected marshes (data not reported). Methods: The study used twelve sections of shoreline (six in a high-energy area, six in a low-energy area) around one coastal lake. All had brackish marsh landward. Oyster shell reefs (25 m long and exposed at low tide) were deposited <5 m offshore of six random sections (three high-energy, three low-energy). The other six sections were left unprotected. Vegetation was surveyed for one year after reefs were installed: three measurements/section/month for shoreline position (i.e. edge of marsh vegetation); nine 1-m² quadrats/section/month for cover of each plant species; three 0.25-m² quadrats/section/quarter for biomass (vegetation cut, dried and weighed).

(Summarised by: Nigel Taylor)