Anthropogenic and Natural Stresses on Coral Reefs in Hawaii: A Multi-Decade Synthesis of Impact and Recovery (NODC Accession 0001063)

In 2002, quantitative photo-transect surveys documenting coral community structure off six coastal sites in Hawaii were repeated to complete long-term data sets of 12 to 30 years duration. Study sites included areas fronting resort development, active and inactive sewage outfalls, and an area where there is no anthropogenic activity, but has been subjected to a variety of storm events. At the only site within a semi-enclosed embayment, erosion from surrounding pineapple fields resulted in a decrease in living coral. Such periodic sedimentation in the Bay drives a cycle of damage and recovery that results in coral community structure different than other sheltered embayments in Hawaii. At the other five sites, located in open coastal waters, coral community structure was not adversely affected by shoreline development or discharge of treated sewage effluent. Long-term studies of pristine reefs under natural stress from episodic storms indicate that recovery along the successional continuum varies with time in the different reef zones. The results of these studies provide a framework for effective and efficient coral reef management in Hawaii. Understanding patterns of natural and man-induced stress and recovery can provide a good model for management strategies, as anthropogenic impacts are superimposed over natural stresses. Our results provide good evidence that management efforts should be concentrated in embayments and areas with restricted circulation. Because such areas comprise less than 10% of the coastal areas, it is concluded that the overall condition of coral reefs in Hawaii is good, and should remain so. While concerns of catastrophic loss from anthropogenic impact to coral reefs are valid in some areas of the world, they do not accurately depict the overall health of coral reefs in Hawaii.