Conservationbi Odiversity

Island Survivors

On what once was a North American Galápagos, researchers try to save devastated wildlife

Guadalupe island, Mexico—"Vermin. Rats with horns. Evil," Jon P. Rebman tells me as we hike across this rugged volcanic island about 150 miles west of Mexico's Baja California peninsula. "I could keep going. They've really eaten nearly everything."

Rebman, curator of botany at the San Diego Natural History Museum, is referring to the some 10,000 goats that have transformed the lush forest of Guadalupe Island into a barren field since they were introduced by sailors some 150 years ago. Now he and his colleagues are searching for the few remaining endemic plants that may have escaped the marauding herd.

We enter a steep canyon that once was shaded by groves of pine, palm and oak trees but is now stripped except for a few sickly palm clumps on each side. Struggling ferns line the inside canyon walls, along with piles of goat waste and bleached goat bones.

Along with Thomas Oberbauer, a botanist from the San Diego Planning Department, and José Delgadillo of Universidad Autónoma de Baja California in Ensenada, Rebman digs plants out of crevasses and scales cliffs to snip out-of-reach shrubs. They find one honeysuckle plant that may never have been seen before on the island, but that's about it.

LOOKING FOR NESTING SEABIRDS isornithologistRobert Pitman of the Southwest Fisheries Science Center in La Jolla, Calif., on a small islet just off Guadalupe Island.

Guadalupe Island once was home to more unique plants than any other island on North America's Pacific Coast: 34, a count that rivaled the biological diversity of the Galápagos Islands. But since the goats arrived, 26 of the island's 156 native plants have gone extinct, including six found nowhere else in the world. Half of the island's pine trees have disappeared since the late 1960s, unable to reproduce because goats eat the seedlings. A cypress forest located 4,300 feet along the island's central spine of mountains is turning into a wasteland of eroded soil, rocks and dead trees, according to Philip Unitt, an ornithologist at the San Diego museum. "It's 95 percent of the way to Mars," Unitt says after spending his fourth day camped among the cypress trees. "The whole ecosystem is dysfunction

al. I knew things were bad, but I wasn't prepared for the reality of what it really was."

Our campsite in the pine forest rests atop a 3,000-foot-high ridgeline, affording us dramatic views of the coastline directly below, as well as examples of how the island has changed. Exotic earwigs—tiny insects with pincers on their tails—infest sleeping bags, boots and food supplies. Sparse, weedy grasses provide little comfort on the sharp lava rocks, and much of the soil is gone. These creatures, along with European starlings and mockingbirds, are becoming the new rulers of Guadalupe's wildlife kingdom. They are displacing less adaptable native creatures, such as the purple-flowered, sausagelike succulent shrub Cistanthe guadalupensis, which survives only on three smaller islets, and the Guadalupe storm petrel, one of five birds endemic to the island that have vanished in the past century. The only native creature doing well is the Guadalupe fur seal, which now numbers more than 5,000. The seal was declared extinct in the early 1920s, but its population has increased 13 percent a year since the late 1950s, when its hunting was banned.

Seventeen U.S. and Mexican biologists sailed to the island in June to collect plants, birds and insects while documenting damage from the vacuum cleaner-like herbivores, which were left by Russian whalers and fur-sealers looking to establish a reliable food source. Scientists have been collecting the island's flora and fauna since Smithsonian botanist Edward Palmer was marooned here for four months in 1875—and became sick from eating too much goat meat. (He managed, however, to bring home 1,200 plant specimens.) But this expedition is the first to use a helicopter, all-terrain vehicles and satellite phones to put researchers into inaccessible places.

One such location is a small islet off Guadalupe's southern tip, whose 400-foot-high cliffs have never been scaled by humans. On a rolling 25-acre meadow atop Islote Adentro, or Inner Islet, we find a trove of native plants—relatives of the poppy, buckwheat, wallflower, morning glory and tar plant—that once covered the entire main island. Because they evolved apart from grazing animals, the plants never developed spines, foul-tasting leaves or other natural defenses and thus were easy pluckings for the goats.

The expedition's organizers believe the way to save Guadalupe Island's ecosystem is to remove the goats as quickly as possible. That would give the island's native vegetation a chance to recover and perhaps bring back some of the birds that depend on it.

William T. Everett, president of the Endangered Species Re

covery Council and one of the leaders of this expedition, says special goat-sniper teams, rather than your average hunter, would do the job from helicopters. When the population was cut down to size, researchers might then deploy a "Judas goat," a radio-collared female goat in heat, to act as bait to attract the remaining males. Everett notes that goats are extremely prolific breeders, and even two or three survivors could make the entire eradication program worthless. "The only goat that really matters is the last one," he explains. "Particularly if it's a female."

Proponents point to the goat removal program at San Clemente Island, a military reservation about 100 miles west of San Diego, as proof that such a strategy could work. Although it took 20 years of court battles against animal-rights advocates, state and federal conservation officials were finally able to declare San Clemente goat-free in 1994. Since then, native trees and plants have made a comeback, as have some of the island's other native fauna. In the coming months, the expedition members will assemble a proposal to the Mexican government detailing their findings and offering a plan to remove the goats. Perhaps the goats' only supporter is the Mexican navy, which operates a small garrison on the southern end of the island and sells the rights to export 1,000 live goats a year to a goat breeder based in Sonora, Mexico.

Exequiel Ezcurra, the museum's research director and a for-

z mer head of the Mexican National Institute of Ecology (equivalent to the U.S. Fish and Wildlife Service), explored the island for the first time on this expedition. He says that a proposal written by Mexican and U.S. scientists has a good chance of gaining support from the Mexican government, despite the navy's opposition. "There is a window of opportunity that did not exist several years ago," Ezcurra remarks. "It's just a question of convincing the right authority in government."

Even the small community of lobster and abalone fishermen on the island realizes the long-term problem of the goats. Al-

though they enjoy an occasional goat barbecue, they have seen much of the plant life around their village disappear. Even worse, their only source of freshwater is a spring that is formed by fog water collected by the cypress forest. As the trees disappear because of goat grazing, so does the water. "It's a good idea to remove the goats," said Raoul Urrias, leader of Guadalupe's fishing cooperative. "We have to take care of the forest."

—Eric Niiler

ERIC NIILER is a freelance science writer based in San Diego.

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