Dispatches from the front lines of coral reef science often make for grim reading, chronicling threats to the “rainforests of the sea.” But few scientists have looked at the effectiveness of reef restoration strategies.
Now a study co–authored by John Kittinger of the University of Hawaii looks to the Northwestern Hawaiian Islands—where U.S. Fish and Wildlife Service conservation history stretches back more than 100 years—and finds reason to hope.
The paper, published in October 2011 in the peer–reviewed online journal PLoS ONE, calls the Northwestern Hawaiian Islands (NWHI) an example of damaged reefs that are now healthy because of changes in the way humans treat the ecosystem.
The islands were designated in 2006 as Papahanaumokuakea Marine National Monument, jointly managed by the Service, NOAA and the state of Hawaii. Hawaiian and Pacific Islands Refuge Complex project leader Barry Stieglitz and coral reef ecologist
James Maragos (a recent Service retiree) generally agree with the study’s assessment.
“There simply aren’t any ‘pristine’ or ‘completely healthy’ reefs,” Stieglitz says, but “the reefs in the NWHI are indeed in pretty good shape.”
Taking the Long View
The study team drew on ecological, archaeological, historical and fisheries data to reconstruct the relationship between human activities and ecosystem health in the Hawaiian Islands from the 13th century to 2009. They documented two periods when coral reefs recovered from devastating human impacts.
On the main Hawaiian Islands, after early overharvesting, the Native Hawaiian people limited catches of some species. The result was partial reef ecosystem recovery in the 15th century, but only until Western contact in the 1800s. Those reefs are in decline today.
The NWHI recovery dates to the 1980s as managers began to repair the damage from overfishing and military use. This recovery is ongoing, the result of changes in land and resource use, reduced human population and the islands’ remoteness.
Hawaii’s Polynesian settlers considered the NWHI sacred and protected their resources. But other nations exploited the islands’ whales, turtles, monk seals, seabird eggs, feathers and guano.
In 1903, President Theodore Roosevelt sent the U.S. Marines to Midway Atoll to protect seabirds. Midway became a military base, but in 1909 the rest of the NWHI were made a reserve, and later a refuge. Some 14 million seabirds nest in the NWHI today.
Midway was a military hub during World War II with a population peak of 5,000. A ship channel destroyed corals in its lagoon. Air bases stockpiled fuels and other toxic chemicals.
The Navy did some cleanup before transferring Midway to the Service, which established Midway Atoll National Wildlife Refuge in 1988. Pollution persists in unmarked chemical waste dumps. Lead paint remediation work is underway, but it will take years.
Cauliflower coral and others species on the reefs off the Northwestern Hawaii Islands are responding well to changes in the way humans treat the ecosystem.
Mark Sullivan/USFWS |
Commercial fishing was phased out from 2006 to 2011. The Hawaiian green turtle is doing well, but three keystone species have not rebounded: pearl oysters, lobsters and endangered Hawaiian monk seals.
Maragos says monk seal pups probably once depended on lobster. Commercial fishers wiped out the lobsters in the late 1970s. “It was like gold fever,” he says. “The population collapsed and never came back.” Lacking that prey, the young seals weaken and are picked off by sharks.
The dredged corals at Midway’s lagoon have not recovered, Maragos says. But elsewhere Papahanaumokuakea’s reefs are healthy, with species found nowhere else in the world.
“There’s a huge number of undescribed species out there,” says Maragos, who was chief investigator on two research expeditions to the remote islands in 2000 and participated in several others. “I found at least 50 (coral) species that have not been described in the literature.”
Stieglitz says the management philosophy for the Midway Atoll and Hawaiian Islands refuges is like the Hawaiian concept of ahupua’a—safeguarding living communities from the mountains to the sea.
“As an agency in the past we have tended to think of the ecosystem ending at the shoreline,” he says, “but what happens immediately offshore is affected by what happens onshore.”
“The primary action was to stop destruction, stop the harm and stop the excessive take of resources,” he says. “If you can do that, these ecosystems have evolved over millions of years, so they’re quite capable of taking care of themselves.”
Heather Dewar is a writer–editor in the Refuge System Branch of Communications.
