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Coral Health Depends on Ridge to Reef Ecosystem Management

HONOLULU, Hawaii, October 4, 2007 (ENS) - Coral reefs suffer when the lands above them are disturbed, finds new research by scientists from Hawaii to Australia. Clearcut logging, farming and development lead to erosion and runoff that kills corals, making it just as important to manage the land above reefs as it is to protect them from overfishing, the scientists confirmed.

Over six years, the researchers studied the connection between watersheds and adjacent coral reefs on three Micronesian islands - Palau, Guam and Pohnpei. The "Watersheds and Coral Reefs" study published in the current issue of "BioScience" magazine describes how multiple threats to reefs combine with lethal results.

"It is clear that sustaining our coral reefs depends on how well we manage human impacts from the mountains to the sea," said Willy Kostka, a co-author of the study and director of the Micronesia Conservation Trust.

"The centuries-old way of managing reefs in Pacific islands recognizes that it is not the coral reefs and watersheds that can be managed, but rather the human activities affecting these ecosystems," said Kostka. "If we provide care and respect to our reefs, they will provide for us."

Sedimentation and runoff from activities on land are among the biggest threats to nearby reefs and are interfering with other marine conservation efforts, such as no fishing zones.

Researcher brushes sediment from smothered coral reef (Photo courtesy Dr. Robert Richmond)
River runoff sends mud into the ocean, where it is compacted around reefs. Algae can outgrow corals to form a mat that traps the mud and prevents coral recruitment. When overfishing occurs, removal of plant-eating fish means algae growth can no longer be controlled, and the reefs are suffocated.

Actions taken by the three Pacific island communities to restore reef health focused on managing entire ecosystems from hilltop to sea floor.

Communities relocated crops from upland rainforests to lowland areas, restored vegetation in watershed areas to control erosion, halted the clearing of mangroves, and established a continuous protected area from the top of the watershed to the reef.

One community is also considering a temporary ban on catches of plant-eating fish.

Fouha Bay, the study site in Guam, is surrounded by steep hills that deer and pig hunters often burn to clear vegetation, which accelerates erosion rates. The bay has high levels of sedimentation that are suffocating the reefs.

Data taken along the southern side of the bay in 1978 and again in 2003 showed a clear loss of coral species and coral cover over time that appears to be due to watershed discharges.

The study's conclusion that coral reefs and other coastal marine ecosystems extend into adjacent watersheds leads the authors to the recommendation that they should be managed as an integrated unit.

"Marine protected areas often will miss their targets of resource protection unless terrestrial protected areas are established and enforced," they write.

Traditional ways of managing human interactions with the reef are still effective in modern times, says the study, citing Palau's Marine Protection Act of 1994 as an example of new legislation for no-take areas based on traditional knowledge of spawning sites.

Vertical wall coral reef on Pohnpei (Photo by David Burdick courtesy NOAA)
On the Enipein watershed on the Micronesian island of Pohnpei, the watershed was located above a marine protected area that was struggling to recover coral and fish populations after clearing of an upland rainforest for cash crops resulted in extensive erosion and sediment deposition on the reef.

Findings from the Enipein watershed research were shared with local chiefs, who decided to create a continuous protected area that begins in the upland rainforest and extends through the mangroves and out to the reef.

Efforts to switch from upland farming to lowland cultivation have been successful, as have been measures to reduce erosion and to protect coastal mangroves.

"Pohnpei, Palau and Guam boast some of the best examples of what can happen when local communities understand their vested interest in nearshore ocean resources and take action to preserve them," said lead author Dr. Robert Richmond of the University of Hawaii's Kewalo Marine Laboratory in Honolulu.

"Reefs are in decline worldwide," he said, "and the Pacific islands of Micronesia are showing us how modern science and traditional knowledge can be combined to reverse that trend.

Co-author Noah Idechong, vice speaker of the House of Delegates for the 7th Palau National Congress, says people know what is occurring but too often lack the political will to make the needed changes that will protect reefs.

"From Pacific islands to the Western world, we know what is threatening our reefs and how to remedy those problems, but policy and political will are lagging behind available science," Idechong said.

"Policymakers often choose inactivity rather than subscribing to the precautionary principle," he said. "This approach undermines our ability to leave a sound environmental legacy for future generations."

Hawaii fisherman Isaac Harp, who did not participate in the study, said, "When foreign land and natural resource management strategies replaced Hawaii's indigenous strategies, rapid degradation of Hawaii's inland and coastal environments began. As indigenous island peoples across 'Pasifika' and beyond understand, when you mismanage your inland environments, negative effects will trickle down and degrade your coastal environments."

"Sometimes we need to move forward by going backward, in this case by recognizing the value of and adopting indigenous management strategies," said Harp. "A thousand years of knowledge is better than a hundred years of assumptions."

Western governments should follow the lead of traditional societies and consider granting near-shore and off-shore leases for community conservation, just as they do for fish cages and oil drilling, the authors propose.

If coral reef resources are not better protected from land-based impacts, the authors warn, they will continue to decline.

Copyright Environment News Service (ENS) 2007. All rights reserved.

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