There may be hope for coral reefs.
Despite the constant hazards that have devastated coral reefs around the world, some coral communities have still managed to recover and persevere. In a study released Monday, researchers identify 38 coral “oases” that have escaped, resisted, or rebounded from the threats facing these vital marine ecosystems.
An Underdog Story
The future has often been bleak for coral reefs. Plastic pollution and overfishing threaten marine ecosystems. As climate change causes the ocean’s temperature to climb, coral reefs undergo mass bleaching events, losing the algae that they rely on for energy. Warmer waters also mean that coral-eating sea stars survive longer, lay more eggs, and cause more damage.
Australia’s Great Barrier Reef, the largest reef system in the world (1,400 miles long and over 2,900 individual reefs), has lost half of its coral cover to bleaching and predation since the 1980s. And a study published last year predicts that if carbon emissions continue as usual, all World Heritage reefs may be lost in 30 years, and all coral reefs worldwide may be lost by the end of this century. That coral reefs can still be found flourishing after facing such an onslaught makes the identification of these 38 “oases” all the more encouraging, the scientists say.
“Coral reefs are in rapid, global decline, but the severity of degradation is not uniform across the board,” James Guest, a marine biologist from Newcastle University in the U.K. who led the research, says in a press release. “What we have identified are coral reefs that are doing better than their neighbors.”
The reasons for each oasis’s success are different, the team noted in their paper, published in the Journal of Applied Ecology. Some have gotten lucky, having never been hit by storms or swarms of ravenous sea stars. Other reefs are particularly hardy, showing resilience against threats. But perhaps the most incredible are the reefs that have recovered from near-decimation, like the reefs of Moorea, in French Polynesia.
In 2005, the Moorea reefs faced hordes of crown-of-thorn sea stars, which eat coral polyps. By 2010, the reefs had almost no coral left. But over the course of eight years, the reef has had a chance to recover, and now over 80 percent of the sea floor is repopulated with coral.
Peter Edmunds, from California State University, Northridge and who studies the Moorea coral reef, was “blown away” by the reef’s recovery. “It is a remarkable example of an oasis,” Edmunds, one of the paper’s coauthors, says in a press release.
The identification of these oases by no means suggests that the coral reefs are not in crisis, the authors note. Although the dangers that reefs face are ongoing, these 38 oases are, according to Edmunds, “kernels of hope” that show that they are not insurmountable.
The method the researchers used to identify the oases resemble a public-health approach. By finding communities of corals that are doing better than their neighbors, future research may identify what’s causing the difference in survival, with a goal of applying that knowledge in conservation.
"This glimmer of hope does not mean we can be complacent about the severity of the crisis facing most of the world's coral reefs,” Guest says. “Using a similar approach in ecology can help us identify areas that can be prioritized for conservation.”