Ocean sanctuaries won't save reefs
Although marine conservation reserves may protect
against local threats, scientists are warning that they
may not offer shelter from wide scale issues such as
climate change.
Image: Istockphoto

According to research presented at the recent Ecological Society of Australia conference in Sydney, marine reserves may help save fish species in the face of climate change but they will not protect the coral reefs that shelter them.
University of North Carolina marine ecologist John Bruno and his former graduate student Elizabeth Selig compared data collected from 8,540 coral reefs in the Indian, Caribbean and Pacific regions from 1987 to 2005. 
They compared coral cover, sea surface temperatures and whether the reef was in a marine reserve or not.

“We found while coral loss was reduced in marine reserves, the rate of coral decline with warmer temperatures was just the same in marine reserves as in highly fished areas,” Professor Bruno said.

He believes the results should sound a warning bell for reef managers, who generally believe marine reserves will be more resilient to climate change.

“The biggest stresses put on coral reefs are ocean warming and disease outbreaks,” he said.

“The stresses are both regional and global in scale and local protection through marine reserves is unlikely to help these reefs resist such changes. Marine reserves are very important for protecting fish populations, maintaining coral reef food webs and protecting against anchor damage but they are unlikely to reduce coral losses due to ocean warming.”

Associate Professor Bruno found marine reserves which have been established for at least 15 years were more effective in reducing coral loss than reserves established recently for a shorter period of time.

Marine reserves were effective in protecting coral from overfishing and pollution but they did not slow the effects of global warming.

"Our results suggest they are not mitigating those threats," he said.

"So they appear to mitigate some stresses, probably more local scale stresses, but they don't seem to be working against regional scale stresses such as coral disease and bleaching."

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