Coral Reefs Vanishing more Rapidly than Thought

Coral Reefs Vanishing more Rapidly than Thought

Aug. 2007  – The central and 
western Pacific Ocean contains 75 percent of the world's coral reefs and 
the world's highest coral diversity, but corals in this region are 
vanishing much more rapidly than previously thought, according to research 
that will be published tomorrow. 
The reefs are disappearing at a rate of one percent per year, a decline 
that began decades earlier than expected, scientists from the University 
of North Carolina-Chapel Hill have learned. The study provides the first 
regional-scale and long-term analysis of coral loss in the central and 
western Pacific, where relatively little was known about patterns of reef 
loss. 
"We have already lost half of the world's reef-building corals," said John 
Bruno, lead study author and associate professor of marine ecology and 
conservation in the Department of Marine Sciences at UNC-Chapel Hill. 
Bruno and ecology graduate student Elizabeth Selig, compiled and analyzed 
a database of 6,000 surveys performed between 1968 and 2004 of more than 
2,600 Indo-Pacific coral reefs.

The surveys tallied coral cover, a measure of the ocean floor area covered 
by living corals. 
Scientists rely on coral cover as a key indicator of reef habitat quality 
and quantity, the way forest scientists would measure an area covered by a 
tree canopy as a gauge of tropical forest loss. 
Bruno and Selig found that coral cover in the Indo-Pacific region declined 
from 40 percent in the early 1980s to about 20 percent by 2003. 
They were surprised to find that coral cover was similar whether reefs 
were maintained by conservationists or were unprotected. 
"This consistent pattern of decline across the entire Indo-Pacific 
indicates that coral loss is a global phenomenon, likely due in part to 
large-scale stressors such as climate change," Bruno said. 
Historically, coral cover hovered around 50 percent. But today, only about 
two percent of reefs in the Indo-Pacific have coral cover close to the 
historical baseline. 
Nearly 600 square miles of reef have disappeared each year since the late 
1960s, twice the rate of rainforest loss, the scientists found. 
Coral disease, predators, rising ocean temperatures due to climate change, 
nutrient pollution, destructive fishing practices and sediment run-off 
from coastal development can all destroy reef communities. 
"Indo-Pacific reefs have played an important economic and cultural role in 
the region for hundreds of years and their continued decline could mean 
the loss of millions of dollars in fisheries and tourism. It's like when 
everything in the forest is gone except for little twigs,a few lone 
trees," Selig said. 
Although reefs cover less than one percent of the ocean globally, they 
play an crucial role for coastal communities, Bruno said. They underpin 
the fisheries and tourism industries and buffer coastlines from storms. 
When corals die, these benefits disappear. 
Policy makers and resource managers searching for ways to reverse coral 
loss do have options, Bruno said. 
"We can do a far better job of developing technologies and implementing 
smart policies that will offset climate change," he said. "We can also 
work on mitigating the effects of other stressors to corals including 
nutrient pollution and destructive fishing practices." 
Funded by a grant by the National Science Foundation and the U.S. 
Environmental Protection Agency's Science to Achieve Results program, the 
study will be published tomorrow in the online journal "PLoS One." 

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