World's coral reefs are recovering but for how much longer?Paris - A report on the health of the world's coral reefs just published shows that some of the areas worst hit by massive bleaching in 1997-98 have begun to recover.
And the greatest progress has been in reefs safeguarded as Marine Protected Areas (MPAs). A main threat to coral reefs, says the report, continues to come from humans. But the report also warns that this year's developing El Nino -an unusual warming of the surface of the tropical Pacific that caused most of the serious 1997-98 global bleaching events - could cause a new setback in recovery. According to the report, coral reefs provide "goods and services" worth an estimated US$ 375 billion per year (e.g. fish, tourism, coastal protection, etc), while 500 million people depend totally or partially on reefs that are being damaged.
The 378-page global report, entitled Status of Coral Reefs of the World: 2002 and published through the Australian Institute of Marine Science (AIMS), was prepared by the Global Coral Reef Monitoring Network (GCRMN), a network of, governments, institutes and NGOs from over 80 countries. UNESCO's Intergovernmental Oceanographic Commission (IOC) is one of the network's sponsors and implementing agencies. GCRMN has been updating its survey every two years since the first report was published in 1998, with contributions from some 150 authors from more than 100 countries.
Bleaching occurs when calciferous coral colonies reject the microscopic algae that live in symbiosis with them, providing essential nutrients with the aid of sunlight, in exchange for shelter. Even a one-degree centigrade increase in water temperature is enough to trigger the bleaching process. In 1997-98 the worst El Nino on record, which caused hotter, drier weather in some parts of the world, was followed by mass bleaching, severely damaging some 16% of the world's coral reefs. Now, according to the report, about half of these reefs are showing signs of "slow to moderate recovery." New corals are settling on reefs along the coasts of East Africa and the Comoros, especially in Marine Protected Areas (defined by the World Conservation Union as areas "reserved by law or other effective means to protect part or all of the enclosed environment"). There has also been "stronger recovery" in the Maldives, the Lakshadweeps (off the south coast of India) and Palau, where there is little direct human impact.
Some 21 coral reefs are listed within UNESCO's Man and Biosphere (MAB) programme and a further 15 are World Natural Heritage Sites, giving governments obligations to provide minimum safeguards and to manage them sustainably. Some of these sites involve local communities in reef management and sustainable fishing practices.
But the picture is not so rosy everywhere. Recovery in the Seychelles, Sri Lanka, the Indian mainland and some parts of Southeast Asia is "slow or barely evident." High levels of sediment transport, nutrient pollution, over-fishing and destructive fishing practices all put a stress on corals that slows their recovery. In Southeast Asia, the economic crash of 1998 put additional stress on the reefs, when city-dwellers returned to their home villages on the coast in the hope of making a living from natural resources. In many reefs, local fishermen still use dynamite and cyanide to stun the fish. In some parts of Southeast Asia and East Africa, though, communities are taking an active part in managing and monitoring their reefs, thanks to awareness-raising initiatives, particularly by NGOs.
The most serious threat to coral reef ecosystems is now the combined impact of stress from human activities and climate change. This year's developing El Nino could create a new set-back for the reefs. And while El Nino previously has occurred in natural cycles of 7 to 11 years, it has become more frequent in the past few decades, possibly as a result of global warming. At a briefing in UNESCO Headquarters last week, Clive Wilkinson, Global Co-ordinator of GCRMN at the Australian Institute of Marine Science and editor of the latest survey, warned, "even the best management will not stop global warming killing reefs. But if you have good management, especially fish management, the recovery will be much better."
Copies of the report can be obtained through the Australian Institute of Marine Science (AIMS); the World Conservation Union (IUCN); the Intergovernmental Oceanographic Commission of UNESCO. See also ReefBase.
See also a new guide to coral reefs in UNESCO Biosphere Reserves, World Heritage sites and RAMSAR Convention sites: Coral Reef Protected Areas in International Instruments. Edited by Bernard Salvat, Jessica Haapkylä and Muriel Schrimm. CRIOBE-EPHE, Moorea, French Polynesia (obtainable through UNESCO).