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Search and destroy in the Galápagos

By Roger Hamilton, Baltra Island, Galápagos

It was an innocent mistake, and the tourist was plainly embarrassed. Before flying to the Galápagos, she had passed through Colombia, where a relative had given her a bag of fruit called feijoa. Now that same bag was in the hands of Lourdes Acosta, uniformed inspector of the System for Inspection and Quarantine of Galápagos (SICGAL).

The tourist had just arrived at the airport on the tiny island of Baltra, the islands’ main port of entry. She and her flight mates were clearly excited to be on these famed islands. They had paid the US$100 entry fee to enter the Galápagos National Park, and were now watching as Acosta and the other inspectors went through their luggage. The inspectors’ job was to look for any plant or animal that could conceivably get out into the wild. Such invasive species, arriving in a suitcase, a cargo hold, or on the sole of a shoe, are considered the greatest threat to the archipelago’s famed ecosystems and its unique flora and fauna.

In all likelihood feijoa trees would probably not have gained a roothold in the islands and posed a threat to native species. But one never knows. Interestingly, this species is in the same botanical family as the guayabo, whose bad reputation in the Galápagos stands in contrast with the esteem in which it is held throughout much of tropical America, where its fruit is turned into a flavorful, vitamin-rich jam. In the Galápagos, the guayabo proved to be too much of a good thing, and today these low-lying trees occupy more than 40,000 hectares of land on four islands. Farmers hate them, because they invade pastures and fields. And conservationists are alarmed to see dense guayabo forests replacing three unique highland vegetation zones in Galápagos National Park.

Acosta wrote up a report on the feijoa incident and sealed the bag, wrapping it round and round with meters of tough plastic tape. The fruit, along with other confiscated products, would be incinerated.

Blocking entry. After centuries of nearly unrestricted immigration of alien plants and animals, Acosta and her coworkers are now putting the squeeze on newly arriving organisms whose spread could further jeopardize the Galápagos’ biological integrity. The program is part of a new quarantine system that began operations in 1999 as part of the Galápagos Environmental Management Plan, which is partly funded by the IDB.

Although still in a learning curve, the SICGAL team has succeeded in blocking the entry of some potentially dangerous biological invaders, including an aggressive species of grass, an insect that is currently destroying mangroves on the mainland, and a fruit fly that could have damaged the islands’ mango trees. Inspectors have also intercepted a number of larger animals that could have gained an offshore foothold, such as crabs, mollusks, and even a hapless rabbit.

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IDB President Enrique V. Iglesias inaugurates a new inspection and quarantine station on Santa Cruz.

SICGAL is also carrying out training programs and community education, as well as establishing new inspection offices in airports and docks and a headquarters building in the town of Puerto Ayora, on Santa Cruz island. The new building, whose volcanic rock construction helps it to blend with the natural landscape, was inaugurated last July by IDB President Enrique V. Iglesias.

Tourists generally accept the increased security measures with understanding and good humor, says Franklin Falconi, who heads the Ecuadorian Agricultural Health Service Operations on the Galápagos, which includes SICGAL. Most are seasoned travelers who have endured countless airport searches by steely-eyed officials looking for bombs, knives, and weapons of mass destruction. It’s hard to get traumatized over the possibility of being caught with a bag of fruit.

The inspectors’ job is not limited to the airports. They also poke around in the cargo holds of boats, and not just in containers of organic materials. According to Falconi, even a box of books will invite their scrutiny, because it could contain cockroaches. Nor are inspections limited to items arriving from the mainland. The SCGAL inspectors keep an eye out on shipments between islands as well.

When inspectors find a prohibited item, they do not fine its owner. According to Falconi, the nonpunitive approach helps to reduce bad feelings and resistance.

Islands of immigrants. Ironically, all plant and animal species on the Galápagos are relatively recent arrivals from the mainland, at least in evolutionary time. In a sense, they are all invasives. This fact lies at the heart of the islands’ extraordinary importance for science. Hitching a ride on logs or floating mats of vegetation, plants and animals colonized what were formerly bare volcanic protuberances. They then went on to evolve into varieties and eventually new species altogether. Charles Darwin's astute theorizing on how this happened has contributed enormously to our understanding of the role of natural selection in the process of evolution.

But it was the arrival of one particular species in 1535 that sparked a veritable avalanche of newcomers. In the centuries after the landing of a Spanish bishop and his crew, the pace of ecological imperialism acquired new orders of magnitude. Later settlers brought with them a complete agricultural kit of plants and animals, not to mention unintended stowaways, from snakes to microbes. Many of these invader species pushed out endemic populations, in some cases to the point of extinction. Meanwhile, whaling ship crews made off with thousands of live tortoises to eat during their long journeys. Scientists and wealthy collectors took thousands of individuals of many species, to study or simply to display. And today, fishermen are locking horns with conservationists over efforts to control overfishing of the sea cucumber and other marine species in Galápagos waters. Never the tidy little laboratory of evolutionary change of popular imagination, the Galápagos’ ecosystems today face increasingly rapid change and disruptions.

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“Judas” goats help to betray the location of their feral equivalents, aiding in the erradicatin campaign.

A plague of goats. Heading the most wanted list of invasive species is the smart, nimble, adaptable goat. Originally introduced for food, bands of goats have stripped whole mountainsides of vegetation, leaving the islands’ emblematic tortoises without food or shade. On the island of Baltra, goats, combined with airport construction, resulted in the demise the a subspecies of a particularly large land iguana, some of which reached five feet in length. Over the past three decades, the Galápagos National Park, with the support of the Darwin Research Station, has eliminated goats from five islands.

On Isabela Island, the largest of the Galápagos and home of the archipelago’s largest number of endemic species, an original herd of goats estimated at 150,000 on the island’s north lobe has been reduced dramatically through air patrols and ground operations using scoped .223 rifles. By the end of 2005, it is considered likely that the north end of the island will be declared free of goats, as well as feral donkeys.

Although it is expensive to prevent new species from arriving on the islands, it costs far more to attempt to control or erradicate them after they have become established. This fact is reflected in the allocation of a grant Ecuador received in 2000, which was leveraged by the US$10.4 million IDB loan for the environmental management program. More than US$1 million from the IDB loan paid for filters in airports and docks to keep out new arrivals, and more than US$7 million from the GEF grant is being ued to eradicate goats.

Also on the Galápagos’ wanted list are feral pigs that eat tortoise eggs and young whenever they can find them. Rats eat tortoise eggs too, killing every hatchling on Pinzon Island for the past century and reducing the island’s tortoise subspecies to a population of over-aged individuals. Cats wreak havoc among the bird and iguana populations. In the late 1970s, wild dogs on Santa Cruz Island killed more than 500 iguanas in a single attack.

The ani, a large black bird appreciated on the mainland for its appetite for ticks on cattle, preys on the nestlings of Darwin’s finches. Meanwhile, these same finches feed on the fruit of introduced and rapidly spreading blackberry bushes, unwittingly broadcasting their seeds in their droppings.

At the micro end of the fauna spectrum, aphids, wasps and fire ants have spread far and fast. The cottony cushion scale, which first appeared on San Cristobal in 1982, is attacking native plants on 10 different islands. Hundreds of new species arrive each year. Most do no harm, but any one has the potential of being the serious pest of the future.

Falconi is proud of the success of the fledgling inspection system. Noting that invasive species are still less of a problem on the Galápagos than on the mainland, Falconi says, “We want to keep it that way.”

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