Invaders Threaten Island Wildlife
GALAPAGOS ISLANDS, ECUADOR — THERE are wasps now on Floreana."They probably came on a stem of bananas," says Fionnuala Walsh, assistant to the director of the Charles Darwin Research Station on Santa Cruz Island. "They came two years ago and now they're all over the island. The experts say there doesn't seem to be any way to control them. You say, well, we've lost that one." The pesky wasps join pigs, goats, cats, rats, dogs, red ants, and other creatures that have found their way to these fabled islands 600 miles off the coast of Ecuador. Much damage and destruction to life and landscape have been done here, despite aggressive conservation efforts to control feral creatures by the Ecuadorean National Park Service and the Charles Darwin Research Station. When Charles Darwin set foot on the islands in 1835, he was astounded at the tameness of the animals. And over the years, the accidental or intentional introduction of species has yet to alter the prevailing fearlessness of most creatures regarded as native here. Even today, ecotourists can walk along paths on the islands and stop two or three feet from blue-footed boobies or masked boobies nesting with their chicks. Along coves and bays, seals bask in the sun and only look up when humans pass. On rocky shorelines, pelicans, herons, frigate birds, and albatrosses are yards away as visitors quietly enjoy an incomparable experience of seeing these birds move about in their natural habitat. At the Charles Darwin Research Station, visitors can touch ancient 500-pound tortoises. Dive in the water with scuba gear, and seals will join the swim. In some places, the Galapagos penguin, the world's smallest, will be there either on a nearby rocky ledge or in the water. Marine iguanas might swim quickly by (using only their tails for propulsion) looking for marine algae to eat. On shore, piles of land iguanas sun themselves on rocks after dining on prickly pear cactus. The iguana ejects excess salt from its nostrils as if it were spitting. Along trails, lava lizards and the leaf-toed gecko scurry out of the way. On the islands of Isabela and Fernandina, the famous flightless cormorant seldom strays inland beyond a few yards from shore. On tree branches, it's easy to spot a host of finches, including the four kinds of ground finches with differing beaks that so fascinated Darwin and contributed to his theory of evolution. (In essence, he concluded that animals isolated long enough will evolve to fit their habitat.) Introduced species, however, are a story of pillage and rampage. For instance, on the island of Pinta, three goats arrived in 1959 (as a source of food). By 1973, a population of 30,000 goats was chewing its way toward total destruction of the vegetation. A program of hunting and killing was launched, and Pinta is free of goats today. On Santiago Island, the wild goats have been reduced slowly from 100,000 to 60,000 over a period of 10 years. But an estimated 30,000 wild pigs there cause severe erosion and eat the eggs and young of birds, land iguanas, and tortoises. Through the efforts of the Darwin station and the Ecuadorean park service, rats have been eliminated from the small island of Bartholomew and wild dogs from the big island of Isabela. Several species of land iguanas have been saved at the research station, along with hundreds of tortoises. Part of the problem is that no quarantine system exists on the islands, and there is no control or monitoring of animals arriving. "The airport at Puerto Ayora and the road into town are not part of the park," says Ms. Walsh, "and anybody can bring in any animal." Godfrey Merlen, a biologist who has lived in the Galapagos for nearly a dozen years, says, "Every so often in Puerto Ayora you see green iguanas wandering around there, an animal that doesn't belong there and which nobody has the slightest idea how it got there." And what to do about the wasps? "We don't know what the effect will be," says Walsh. "It could prove to be irritating, but not a real problem. We're trying to get funding for a project now to see if there will be competition between it and the native bee. But we know it's spreading fast."
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