|Bourgeois, R - UNIV. OF LA-LAFAYETTE|
Submitted to: Journal of Coastal Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 19, 2003
Publication Date: N/A
Interpretive Summary: Beach restorations of barrier islands can be beneficial to coastal marshes, but may also have detrimental effects on intertidal macrobenthic communities. The effects of a recent beach restoration of deep-burrowing ghost shrimp populations was investigated through comparisons of sediments from disturbed and undisturbed sites, and monitoring population recovery at the restored sites. Locations that had undergone beach restoration showed no minimal evidence of population recovery 2 years post-restoration. Sediments at the primary restoration site were high in silt/clay composition which may have prevented larval recruitment and population recovery. This information can be used to design more appropriate restoration plans that account for macrobenthic communities.
Technical Abstract: Two barrier islands of the Isles Dernieres chain of Louisiana were recently renourished with dredged sediments taken from the adjacent estuary. This study addresses the impact of beach restoration on intertidal populations of the burrowing ghost shrimp, Callichirus islagrande. Sediment characteristics of the restored sites and neighboring sites (both with and without shrimp) were compared and the effect of sediment alteration of recolonization rates was examined. Beach height was increased by an average of 2.4m. Differentiation among sites with respect to silt/clay, sand, and shell fractions was significant (P < 0.001). East Island, the primary site of restoration, had the largest proportion of silt/clay sediments (40% of total) whereas Trinity Island had the largest proportion of shell (12%). Minimal population recovery (total = 3 individuals) was evident 2 years post-restoration. High levels of silt/clay loading at East Island appear to have slowed population recovery.