Improving scientific decision-making in the restoration of ship-grounding sites on coral reefs

When ships contact reefs they break and crush coral rock, kill corals and o ther sessile organisms. open bare space for colonization, and eliminate top ographic (habitat) complexity. We explored the ecology of ship groundings a nd the scope of restoration possibilities. Our guiding hypothesis was that high-relief areas damaged by ship groundings would not recover to their ori ginal community structure without restoration, but instead would converge o n an alternate community state similar to natural hardground communities. T o test this hypothesis, ship-grounding sites in the Florida Keys National M arine Sanctuary (FKNMS) were surveyed repeatedly and compared to surveys of undamaged reference sites at the same depths. In a study of the 1984 MV WE LLWOOD ship-grounding, many univariate parameters of the community structur e of the ship-grounding site in 1995-1996 resembled a nearby natural hardgr ound reference site more closely than they resembled the spur-and-groove ha bitat adjacent to the spur-and-groove that had been flattened by the accide nt. The WELLWOOD site was also more similar to another hardground reference site, a century-old ship grounding at Pickles Reef, than it was to the ori ginal spur-and-groove community configuration. The WELLWOOD study suggests that damaged spur-and-groove habitat will not recover rapidly to its former state and that it may not recover at all without substantial restorative e ngineering. In contrast, the MV ELPIS grounding site, which damaged an exis ting hardground community, was statistically indistinguishable from adjacen t hardground sites less than 10 yrs after the incident. If these results ca n be generalized, when a ship grounding occurs in a hardground habitat, the community may recover on a decadal time scale. Substrate stabilization and coral transplantation will likely speed this natural recovery. Considerati on of ecological setting is important in the design of restoration projects , ensuring preservation of the resource for future generations.