Historical coral reef declines featured in this week's Science

August 14, 2003

No coral reef system in the world can be considered pristine, concludes an exhaustive historical analysis of human exploitation of reef ecosystems in the August 15 issue of the journal Science. The hunting of big turtles, fish, manatees and crocodiles began a process of reef decline exacerbated in the modern era by continued overfishing and global warming.

Coral reef research evolved after the invention of SCUBA, only about 50 years ago. But humans have fished highly productive and biodiverse coral reefs for thousands of years.

John Pandolfi, paleoecologist at the Smithsonian´s National Museum of Natural History and collaborators examine the question of global reef degradation beginning before human presence was felt. "These historical analyses provide us with a glimpse of what reefs were like in the absence of human influence. We have a baseline that doesn't shift, helping to put the current crises into perspective," said Pandolfi.

"In the absence of a time machine, few have the skills to illuminate our understanding of marine ecosystems with historical perspective. John makes a career of delving into the past to understand reef ecosystems," said Bruce Hatcher, professor of biology at Dalhousie University, Halifax, Nova Scotia.

The team rated groups of reef organisms (large carnivores, large herbivores, small carnivores, small herbivores, corals, suspension feeders and seagrass) from 14 reef ecosystems on a scale from pristine to extinct for each of seven different periods of human culture: prehuman, hunter-gatherer, agricultural, colonial occupation, colonial development, early modern, late modern, to present.

Richard Cooke, archaeologist at the Smithsonian Tropical Reseach Institute (STRI) in Panama and coauthor emphasizes: "Long historical records, often ignored by scientists and planners, are powerful tools for understanding the relationship between present and pristine states of ecosystems. Humans have never been innate conservationists. A point-of-no return looms so large for coral reefs that only draconian measures against human exploitation will ensure the survival of these fragile ecosystems in to the next decade."

Top carnivores and reef grazers are the first to go when humans enter the picture. Some, like the Caribbean Monk Seal, are already extinct. Historical declines in all 14 reef ecosystems could be explained almost entirely based on the status of these two groups.

This long view of marine ecosystems shows that most of the world´s reefs were substantially degraded by overfishing and pollution even before our great grandparents were born. Coral mortality due to disease and bleaching is a much more recent phenomenon and reflects additional stress on an already highly impacted system.

The study also found that reefs in the Western Atlantic (Jamaica, Panama), where exploitation by shoreline inhabitants has been extensive since human colonization began, have suffered greater losses than offshore reef ecosystems such as those in Australia.

"Historical analyses are an essential tool for understanding the current state of coral reefs, how they got to that state, and for devising a strategy for their restoration," said Pandolfi.

This study continues the emphasis on marine history established in a Science cover story (July 27, 2001) by coauthor Jeremy Jackson, Scripps Institution of Oceanography and STRI, and a large group of colleagues. Jackson often compares a researcher or resource manager informed by history with a physician who is much better able to cope with an emergency when s/he has access to the patient's medical history.

John Ogden, professor of Marine Ecology at the University of South Florida and Director of the Florida Institute of Oceanography said: "Pandolfi and his co-workers demonstrate that no reef system in the world has escaped human disturbances. This result will resolve much scientific and reef management confusion on the causes of coral reef decline and will help advance the use of ocean use planning and zoning, particularly fishing prohibition zones or marine reserves, as a major tool of coral reef conservation."

New research initiatives should be explicitly designed to generate information about ultimate and proximate causes of reef decline, and about the ability of reefs to bounce back after disturbances. Finally, Pandolfi underscores the need to dramatically increase the percentage of No Take Areas in marine parks and to foster inter-governmental cooperation to reverse the destruction of some of the most highly productive, beautiful ecosystems on earth.
Global trajectories of the long-term decline of coral reef ecosystems.
John M. Pandolfi, Roger H. Bradbury, Enric Sala, Terence P. Hughes, Karen A. Bjorndal, Richard G. Cooke, Deborah McArdle, Loren McClenachan, Marah J.H. Newman, Gustavo Paredes, Robert R. Warner, Jeremy B. C. Jackson. Science, August 15, 2003.

The Smithsonian's National Museum of Natural History is located at 10th St. and Constitution Avenue N.W. in Washington, D.C. It is the most visited natural history museum in the world, welcoming more than 6 million people last year. The museum is dedicated to the maintenance and preservation of the world´s most extensive collection of natural history specimens and human artifacts. http://www.mnh.si.edu.

The Smithsonian Tropical Research Institute, headquartered in Panama City, Republic of Panama, is one of the world´s leading centers for research on ecology, evolution and conservation of tropical organisms. http://www.stri.org

Smithsonian Tropical Research Institute

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