There was a time when the Galapagos Islands were considered remote and almost beyond reach. Biologists would count themselves truly fortunate to visit the inspiration for Darwin’s evolutionary principles, and there were essentially no casual tourists. But that is no longer true today. In fact, the intense pressure of visitors threatens the entire ecosystem.
There were 173,000 tourists recorded in 2008. Each person requires basic resources like accommodation and food. So there has been a huge increase in hotel construction and imports from the mainland. This also means a lot of ships and aircraft travelling between the islands and mainland Ecuador.
With all the movement, unwanted visitors are also making the trip. Alien species have stowed away since the early days of exploration, but the numbers are on the rise. Roughly one hundred years ago, 112 introduced species were recorded. In 2007, there were 1,321 alien species. These include a wide range of organisms from feral goats to weeds. Many of the early alien introductions were deliberate, as settlers established on the islands and brought domestic livestock and pets.
The local authorities use control measures to prevent new species from establishing on the Galapagos. For example, aircraft are sprayed to eliminate insects from hitching a ride. But there are invaders getting through. Fire ants and parasitic flies are making their presence felt. Microorganisms are also a problem – just last year, avian malaria arrived in the Galapagos penguin population.
In 2007, UNESCO modified the Galapagos’ status as a world heritage site – adding “in danger” to the designation. Just a year ago, a grant of more than $2 million was allocated to invasive species management. The Galapagos are particularly sensitive to all these new species. Millennia of isolation has led to organisms uniquely adapted to their habitat and ill-equipped to withstand predators and competitors. Even in Darwin’s time, introduced species were causing extinctions. Cattle on Floreana ate all the prickly pear cactus and caused the disappearance of the Galapagos mockingbird.
Control strategies range from preventing new introductions to eradicating established species. Containment of affected areas and biological control are also part of the management schemes. There are some success stories already. Feral pigs, goats, and donkeys have been removed from some islands. Fire ants are no longer seen on Marchena Island. A parasitic insect, the cottony cushion scale, has been eradicated from mangrove areas around the archipelago.
Management is both expensive and taxed by the arrival of new alien species. While tourism dollars are important to the economy of the islands, they are not directly going to the problem of invasive organisms. It may be necessary to place some limits on visitors if other control measures are insufficient.
While other areas are also struggling with invasive species, the Galapagos are both iconic and unique. It is particularly ironic this year, as it is the bicentenary of Darwin’s birth.
Photo credit: Doug Miller
