Coral Reefs Down, Not Out

According to two new studies in the 15 August 2003 issue of Science, humanity has been damaging and overexploiting coral reefs for a long time, and continues to do so at increasing levels, leaving no reef is safe—though some reefs are more resilient than others.

John Pandolfi and colleagues report that people have been steadily injuring coral reefs since the hunter-gatherer era of human history, and that coral reef ecosystems will not survive for more than a few additional decades unless they are promptly and aggressively protected from human exploitation.

The authors reconstructed the ecological histories of 14 coral reefs around the world. They found that humans degraded each of the reef ecosystems studied long before the recent and massive coral deaths caused by disease and bleaching. The researchers say that overfishing and pollution run-off from land are to blame for the early and consistent destruction of coral reefs.

The recent coral reef die-offs, caused by disease and bleaching, could be the straw that breaks the coral's back, according to Pandolfi. Earth's coral reefs were in trouble long before these most recent ecosystem tragedies, however, and would still be in serious peril even if disease and bleaching disappeared tomorrow.

In a separate study, Terry Hughes and colleagues report that projected increases in carbon dioxide and temperature over the next 50 years will exceed the conditions under which coral reefs have thrived over the past half million years. They suggest, however, that reefs will change rather than disappear entirely. In fact, some species are already showing far greater tolerance to climate change and coral bleaching than others.

Coral reef management strategies must be designed and implemented through international, co-operative efforts because reefs do not observe human borders, say the authors. Protected reef sanctuaries, called "no-take areas," must be vastly expanded to support reef resilience and to provide a safe place for the breeding of the fish and other creatures that are crucial to coral reef ecosystems. In addition, the authors argue that governments should enact strong policy decisions that reduce the rate of global warming.

—Daniel Kane

14 August 2003