Coral reefs off the Philippines and Indonesia are among the richest--and most endangered--marine habitats in the world, according a new global ranking. The survey, published in the 15 February issue of Science, confirms that some tropical coral reefs provide homes to a remarkable number of marine species. But it also suggests that many marine organisms have far more restricted ranges than once thought, making them especially vulnerable to extinction.
The nooks and crannies of jagged coral banks can shelter a carnival of species. But which reefs boast the most impressive collections of life has been a mystery, because biologists lacked enough information to draw global conclusions. Now, an international team led by marine scientist Callum Roberts of the University of York in the United Kingdom has pieced together the first large-scale map of living marine treasure.
To make their map, Roberts and his colleagues charted the known geographic ranges of 3235 species, including reef fish, corals, snails, and lobsters. They found that some reefs were home to more species than others. A 200,000-square-kilometer coral patch off the Philippines, for instance, contained nearly 1500 species, making it the richest spot in the survey. The Sunda Islands east of Indonesia came in a close second, while reefs off Southern Japan finished third in a list of 18 biodiversity hotspots. Often, the researchers found, the coral hotspots were directly adjacent to biodiversity hotspots on land.
The team found trouble in these paradises, however. The Philippine and Indonesian reefs, for instance, are threatened by destructive fishing practices (such as using dynamite), land-based pollution, and silt. And up to half of all the surveyed animals have "highly restricted" ranges, meaning it's not easy for them to run or hide from threats.
The study "pretty much debunks the myth that marine species are extinction-proof," says Roberts, who hopes the map will serve as a guide to conservation efforts. Even in highly vulnerable areas, he notes, there are still undamaged reefs that--if protected--could help preserve vulnerable species. And Joan Roughgarden, a marine ecologist at Stanford University, says such maps will help marine conservation biologists catch up to their land-based colleagues. "The marine work has been years behind," she says.