Tourists snorkeling at Isla Bartolome as they visit Pinnacle Rock in the Galapagos. Mostly because of increased tourism, UNESCO has added the Galapagos archipelago to its "in danger list."

NYT / Michael Nagle

For anyone touring the Galapagos Islands, it is hard to imagine the globe’s first World Heritage Site is at risk. The marine reserve is populated with sea turtles and humpback whales, and the national park’s trails are inhabited by herons and albatrosses.

Yet last June, UNESCO added the archipelago to its “in danger list,” specifically citing the fragile ecosystem and the negative effects of a sizable growth in tourism. The number of visitors to the Galapagos rose more than 250 percent to 145,000 in 2006 from 40,000 in 1990, while the number of commercial flights to the area has increased 193 percent from 2001 to 2006.

“Unless we start to make fundamental changes right now, in the next 10 to 15 years we will see the Galapagos suffer from both economic and environmental degradation,” said Dr. Graham Watkins, executive director of the Charles Darwin Foundation, whose mission is to conserve the Galapagos through scientific research. “What we have here is an unsustainable model of development,” he added in a telephone interview from his office in Ecuador.

According to a May report by the Darwin Foundation, “Galapagos at Risk,” of which Watkins, a zoologist and ecologist, was a co-author, the islands’ crisis does not just stem from an unprecedented rise in tourism, but also from a change in the marketplace.

“Early tourism in the Galapagos was characterized by nature-loving tourists,” the report said, seeking “to learn about Darwin and see the amazing species that helped him to develop his theory of evolution.” It noted that these guests were “easily accommodated by smaller, locally owned tour operators.”

But, the study continued, the market expanded to include “eco-tourists,” who also like to visit places like Machu Picchu, the Ngorongoro Crater in Tanzania, Easter Island and the Great Barrier Reef. This segment is “often more selective in terms of required comfort and is better served by multinational tour operators,” the report said.

A CONSEQUENCE has been that local owners cannot compete with the foreign-run companies doing business in the Galapagos. Of the $418 million generated by tourism annually, only $63 million is estimated to enter the local economy. And of the 80 tourism boats allowed to operate in the Galapagos, only about 40 percent are locally owned.

“We have to think about the people and not just the plants and animals, or it will all collapse,” Watkins said.

One of the larger multinational companies in the area was Voyages of Discovery, which until recently was allowed to bring one 500-passenger ship into the islands each month.

“It is ironic that we are no longer permitted to call here, considering we had to operate under stricter environmental guidelines than any of the other boats,” said Mark Flager, vice president for sales, marketing and passenger services at Voyages of Discovery, of Ecuador’s decision last fall to rescind his company’s permit. Though Discovery passengers were transferred to smaller boats to visit the national park trails, which can only be explored with a park department guide and a fixed itinerary, some feel large vessels are incongruous with the spirit of a site UNESCO has called a living museum.

“I don’t want to say that only Birkenstock types can come here,” said Johannah Barry, president of the Galapagos Conservancy, which supports preservation and research in the Galapagos, including the Darwin Foundation’s work. “It is just that now it has been Disneyfied, and the high number of people visiting is leading to a different type of experience. It becomes less reflective of the surroundings.”

She added that all the boats waiting to ferry passengers ashore take away from the natural scenery. Watkins said: “The big boats are basically hotels that sit in the port. Those passengers are not staying in locally run hotels or eating in the local restaurants.”

But Flager said Voyages of Discovery’s tour helped local residents even beyond the computers it donated to a school. “Some of our customers even cleaned up litter on one of the beaches in San Cristobal one day without anyone asking them to do so,” he said, adding that Discovery’s passengers were all “moved by the grandeur of the Galapagos” and returned home as environmental ambassadors for the area.

The success of the travel business is also drawing Ecuadoreans from outside the islands to move to the Galapagos with the hope of getting a share of the tourist money. Newcomers have flocked to Galapagos Province, putting pressure on its natural resources and introducing invasive species. As a result, the Darwin Foundation report said, the Galapagos now has 748 species of introduced plants compared with 500 species of native plants. Fifty-five of these new species, it added, have the potential to cause “severe impacts to native biodiversity.”

AN INCREASE in flight arrivals and the growth of activity sports like sea kayaking and sport fishing are also worrisome, according to Watkins. “People moving from island to island in boats make it harder for us to put up barriers to prevent the introduction of new invasive species or infection,” he said, adding that arriving planes are now sprayed to kill insects.

The Ecuadorean government, conservation groups and other organizations are working to develop a new sustainable plan for the Galapagos Islands. “Recognizing the problem was the first step,” Watkins said.

But neither he nor Barry wants to dissuade tourists from visiting. They hope travelers will see what Watkins calls “the Mona Lisa of natural places in the world.” Though he advises visitors to stay longer and spend money at local companies or those that are trying to benefit the local economy.

There is one indisputable upside to tourism in this endangered area, though. As Barry put it, “We have found that when tourists actually visit the Galapagos, they leave caring about it and wanting to support all conservation efforts.”