The Great Barrier Reef (pictured) has lost about half its coral over the past 27 years, according to data from more than 2,000 surveys of 214 reefs. But addressing local threats could tip the balance towards an increase in coral cover in the short term, even in the face of continuing climate change, researchers say.
Glenn De'ath of the Australian Institute of Marine Science in Townsville and his colleagues analysed the survey data and found that the mean percentage of coral cover declined from 28% to 13.8% between 1985 and 2012. Typhoons and outbreaks of the native, coral-eating crown-of-thorns starfish (Acanthaster planci) accounted for about 48% and 42% of the decline respectively. Bleaching related to climate change was responsible for 10%.
If severe starfish outbreaks could be prevented, perhaps by reducing nutrient run-off to the area, coral cover could recover at a rate of up to 1% per year, the researchers say. However, stabilizing global temperatures will be key to the long-term success of this strategy.
Proc. Natl Acad. Sci. USA http://dx.doi.org/10.1073/pnas.1208909109 (2012)