By Juliet Eilperin
Washington Post Staff Writer
Monday, March 30, 2009
SANTA CRUZ ISLAND, Calif. -- The tiny fox scurrying across the lush green landscape, whose ancestors probably floated here 18,000 years ago on storm debris, wore an unlikely testament to its survival in the wild: a radio collar.
The collar helped explain why the Santa Cruz Island fox, along with several other species scattered across Southern California's Channel Islands, are recovering from the brink of extinction. Even as habitat destruction and other pressures threaten plant and animal species across the United States, a concerted restoration effort is demonstrating that it is possible to rebuild an ancient ecosystem that had disintegrated because of human habitation.
It is uncertain whether the success achieved on this 160-mile-long archipelago can be easily replicated on the mainland. But it helps to prove that just as isolated island habitats can fall apart when humans ignore the consequences of their actions, they can also rebound quickly under ca reful scientific management.
"Without intervention, the island fox would have perished, a one-of-a-kind place would have disappeared and the native habitat you're seeing flourish now would be gone," said Lotus Vermeer, director of the Nature Conservancy's Santa Cruz Island Preserve.
Santa Cruz is the largest of the eight islands, a grouping that collectively is home to more than 2,000 land and aquatic species, of which 145 live nowhere else on Earth. Channel Islands National Park incorporates five of them -- Anacapa, Santa Cruz, Santa Rosa, San Miguel and Santa Barbara. The Nature Conservancy owns 76 percent of Santa Cruz and runs it jointly with the National Park Service. The Navy controls San Clemente and San Nicolas, and a private group, the Catalina Island Conservancy, oversees Santa Catalina.
The islands' distance from the California mainland, which ranges from 12 to 70 miles, allowed a variety of distinct species to evolve there over tens of thousands of years. They include the island scrub-jay on Santa Cruz, the Anacapa deer mouse, the unique Santa Rosa subspecies of the Torrey pine and the Santa Catalina Island ironwood, a member of the rose family.
An array of birds, including the rare Xantus's murrelet, the California brown pelican and Cassin's auklet, also depend on the islands for shelter and sustenance.
"We pretty much would not have breeding seabirds in Southern California if it was not for these islands, because they're predator-free and free of disturbance, and close to a good food source," said Kate Faulkner, chief of natural resources management for Channel Islands National Park.
But this was not always the case. In the 1800s, people brought alien species to the islands, including sheep, pigs, cattle, deer, elk, cats and rats. The animals distorted these isolated ecosystems in myriad ways by destroying vegetation and attracting still more predators, which decimated the archipelago's six distinct subspecies of island fox and other native animals.
Golden eagles, lured by the easy prey of baby feral pigs, also feasted on the foxes. "They were picked off by golden eagles like popcorn," Vermeer said. The three subspecies on Santa Cruz, San Miguel and Santa Cruz declined by more than 90 percent by the late 1990s, and all three were listed as federally endangered in 2004.
In the 1980s, the Nature Conservancy, the Park Service and the Fish and Wildlife Service jointly launched a restoration program on Santa Cruz that was replicated on the other islands. Over a decade, the organizations killed 40,000 sheep and a few thousand cattle on Santa Cruz, and by 2006 they had also eliminated 5,036 feral pigs. Since 1999, managers have captured and relocated 32 golden eagles, none of which have returned to nest.
The Conservancy placed radio collars on the 100 remaining Santa Cruz island foxes so it could track them weekly. Vickie Bakker, a Smith Conservation Research Fellow at the University of California at Santa Cruz, is doing computer modeling to monitor how the island fox population is expanding and determine when it will be out of danger.
As a precaution, conservationists and federal officials established captive breeding facilities for all three fox subspecies, which produced offspring that were released into the wild. There are now more than 700 foxes roaming Santa Cruz, more than 100 on Santa Rosa and close to 130 on San Miguel. The Santa Cruz foxes may be fully recovered within a few years, Vermeer said, putting them on track to be one of the nation's fastest-recovering species.
Federal officials have worked to eradicate exotic species on other islands and to reintroduce species that used to thrive there. They killed off the rats on Anacapa Island with two drops of poison bait in successive years, an effort that led to a resurgence of the native deer mouse and Xantus's murrelets. They reintroduced bald eagles, which had disappeared from the islands after DDT contamination weakened their eggs. The bald eagles had been raised in the San Francisco Zoo or captured in Alaska, and there are now at least 40 nesting pairs on the four northernmost islands.
For better or worse, mostly closed ecosystems such as the Channel Islands can be more easily manipulated than their mainland counterparts.
"We can cause damage pretty easily by introducing non-native species, but we also have the ability to reverse some of the impacts," said Faulkner, the park official.
The restoration efforts have sparked controversy as well, however, as hunters and animal rights activists questioned whether it was proper to deliberately wipe out species that had survived on the islands for decades. The Channel Islands Animal Protection Association decried the killing of Santa Cruz's pigs, calling it "a mad dash to kill a species that has existed on the island since 1852."
Former congressman Duncan Hunter (R-Calif.) tried to protect a game reserve on Santa Rosa, saying that if wealthy hunters could no longer pursue the deer and elk introduced in the late 1800s, at least wounded veterans should have the chance. His effort failed, and the deer and elk are set to be removed by 2011.
Park Service spokeswoman Yvonne Menard said that the restoration efforts have involved difficult choices, but that the program's mission is broader than any one species. "That's the purpose of national parks -- preserving places for generations to come, and preserving ecosystems is the challenge today," she said.