When the National Park was declared in 1959, the Galápagos had an unfortunate legacy of introduced animals and plants that were detrimental to the native creatures. Dogs, cats, pigs, goats, rats, guava plants, and the chinchona (quinine) tree are among the non-native species introduced by previous visitors, fishermen and colonists. Herbivores such as goats, compete with native tortoises and iguanas, making food less available and destroying native vegetation. Predators, such as dogs and cats, kill native animals and have seriously depleted native populations. Introduced plants have spread, particularly in the moist highlands, and compete with native vegetation. Several species are considered to be serious threats to native vegetation.

Of great current concern is the situation on Isabela island, particularly in the region around Alcedo Volcano. Here a rapidly expanding population of feral goats has exploded to approximately 40,000 in number, where fewer than 20 years ago none were found. Their voracious appetite for the plant life in the region is threatening the very survival of the Alcedo subspecies of the Galápagos tortoise, and causing deforestation and erosion.

As well as introducing animals and plants, people have hunted large numbers of animals in the past and have cleared great areas of native vegetation for agriculture and ranching purposes. Tortoises, iguanas, fur seals, doves, and other birds, have all been killed at one time or another for food or just pleasure. Colonists in the agricultural zones of the main islands are known to kill owls in considerable numbers even now.

Background

The history of man's detrimental effects on the islands extends back to the 1600s when buccaneers killed tortoises for food. Fur seals were exploited and nearly driven to extinction by North American and European hunters during the 1800s. Once settlers came to the islands, they brought with them a full range of domestic animals, some of which went wild and started feral populations. Whalers and fur sealers captured tens of thousands of tortoises to stock their ships with fresh meat. Females in particular were taken as these tended to occur at lower elevations. During the late nineteenth and early twentieth centuries, vast numbers of tortoises were slaughtered for the fine oil that could be rendered from their fat. In addition, scientific expeditions in the first half of this century took numerous specimens for museums.

Perhaps even more devastating than man's direct predation has been the introduction of exotic plants and animals. Feral goats have seriously altered the natural vegetation on a number of islands. Their tough constitution and rapid reproductive rate has allowed their population to thrive at the expense of other animals and the native vegetation. Several plant species have become at least locally extinct because of the goats.

Dogs are a serious danger on many islands because they prey upon young tortoises and tortoise eggs, as well as upon land and marine iguanas and penguins. Pigs abound on some islands where they destroy vegetation, dig up and destroy tortoise and turtle eggs, and prey upon young tortoises and ground-nesting birds. Pigs are a major problem for the tortoise populations on Santa Cruz and Santiago islands. A close associate of man, the black rat, occurs on many islands. It has probably led to the extinction of endemic rice rats on four islands; it kills and eats tortoise hatchlings and Hawaiian petrels as well. Cats, burros, cattle and horses are present on many islands, but their effects have not been fully assessed.

Invertebrates too may be serious pests. The little fire ant, Wasmannia auropunctata, is present on five islands where it is a nuisance to people as well as having detrimental effects on the populations of other arthropods. Recently, a species of wasp has been introduced. It is aggressive and has been seen on many islands as well as out to sea. It is not known what its effects on native species will be, but we can be sure that it will compete with the native wasps and may eat caterpillars, an important food source for young finches. Only six of the main islands -- Fernandina, Genovesa, Marchena, Rábida, Santa Fé, and Española -- are free from introduced organisms, but through the continued good work of the National Park Service and Charles Darwin Research Station personnel, it is hoped this number will increase.

The Solutions

The solutions to the problems of reviving native populations and eradicating exotic ones are complex and expensive. For example, it is no easy task to eradicate over 100,000 goats from Santiago. The Park Service and Research Station have made remarkable progress over the last two decades, especially considering the chronic shortage of funds.

Notable successes to date have been the eradication of goats from five islands (Española, Santa Fé, Rábida, Marchena, and Pinta), the virtual eradication of goats on Pinta, and of dogs on Isabela. Many exotic populations remain, however, and control programs need careful research and much money to carry out. Contributions are urgently required to fund these programs.

Since 1965, conservation personnel have been actively trying to boost the threatened populations of endangered species. Tortoise nests are protected, and eggs and young are brought to Santa Cruz for captive raising followed by repatriation once they are no longer susceptible to predation.

A remarkable success story is that of the Española Island tortoises. When captive breeding programs began for this race, only two males and ten females survived on the island. Later, a third male was kindly returned to the islands by the San Diego Zoo. Since then, well over three hundred young tortoises have been repatriated. Some of these tortoises are now breeding back on their native island. Many tortoises have been repatriated to Pinzón Island in the same way.

Since February of 1992, Lonesome George, the last individual from the Pinta Island subspecies, has been placed with two females from Wolf Volcano, Isabela, in the hope that offspring may be produced that might be used to repopulate Pinta Island.

Land iguanas have suffered from the depredation of dogs on Isabela and Santa Cruz islands and so are also raised in captivity. In 1982, the first iguanas were returned to Isabela but unfortunately it seems that these were eaten by cats. On Baltra Island, land iguanas been absent since the World War II, possibly as a result of disturbance by service personnel stationed there. Fortunately, a scientist had transferred a few individuals to nearby Seymour a few years before. Some of these individuals have survived. Two have been brought to the Darwin Research Station where they have now bred successfully. One of these individuals is the largest known Galápagos land iguana, weighing 7.5 kg.in 1991.

The dark-rumped (Hawaiian) petrel is probably the only endangered bird species in the islands. This is due to predation by dogs, cats, pigs, and rats on the adults and young in their nesting burrows. This species is in even more danger in Hawaii, so predator control at the petrel colonies has become essential for these populations to survive. Before recent work began on Floreana, the breeding success of petrels was only 30 per cent (with 30% adult mortality). Now as a result of the work of Felipe and Justine Cruz and the Galápagos National Park Service, the petrel colonies have 80 per cent breeding success and virtually no adult mortality. The main thrust of the work was to reduce predation by the poisoning, hunting and trapping of rats and cats. Stephen Kneiss and Richard Podolski are attracting prospective breeders to specific sites where protection from predation can be provided. As a result of these projects, dark-rumped petrels are a much more common sight than they were in 1980.

Education

Education is another very important function of the Park Service and Research Station. Tourist guides and park wardens are trained in park management and natural history. Ecuadorian students are trained in conservation and scientific methodology with the hope that they will later work in Galápagos conservation. Environmental education is carried out in the islands for local residents and their children, and on the mainland as well, to promote environmental awareness. The Charles Darwin Research Station has a library and resident scientific staff who are always willing to provide information. Since 1973, the Van Straelen Museum (named after the first president of the Charles Darwin Foundation) has served as an interesting and informative interpretative center. It contains many exhibits and displays about the natural history of the islands and is well worth a visit.

Concerns still exist regarding the number of tourist boats operating in the islands and the number of tourists visiting. There appears to be no clearly defined limit on either of these. The National Park needs a revised master plan and and a greater commitment of funds to both government and private conservation programs.

Despite the ravages caused by man to these islands' natural inhabitants in the past, there is good cause for optimism. With your support, and that of others, we can hope to return these very special islands to a more natural state and to keep them that way for the future.

-- Michael H. Jackson