Artificial reefs as a reef restoration strategy in sediment‐affected environments: Insights from long‐term monitoring

Abstract

AbstractArtificial reefs provide substrates that facilitate the rapid recruitment of marine biota such as corals and fish, and are commonly employed as coral restoration tools to assist recovery in degraded areas. While this strategy is successful in the immediate years post‐deployment, its contribution to restoration over longer time scales is less well understood.The biological communities on Reef Enhancement Units (REUs), which had been deployed for more than a decade on Singapore's sediment‐affected coral reefs, were surveyed.The diversity of sessile lifeforms on the REUs was significantly higher in 2014 (H′ = 1.03) than 2004 (H′ = 0.60). Hard corals and coralline algae contributed most to the temporal dissimilarity and turf algae remained the dominant lifeform category in both years.In 2014, hard corals and abiotic components contributed most to the spatial dissimilarity among the six REU plots that were surveyed. Shannon diversity values of these plots ranged from 0.74–1.3. Scleractinian cover ranged from 0.4–31.5% and differed significantly among the plots.The REUs also augmented ecosystem functioning at their respective plots. Colonies from 10 of the 30 scleractinian genera recorded were sexually mature, and a total of 119 sessile and mobile reef taxa utilized the REUs for food and habitat.The results demonstrate that artificial reefs can contribute to the development of biological communities and ecosystem functioning in degraded coral habitats over the long run, and underscore the need for long‐term monitoring to validate the effectiveness of reef restoration efforts.