With forces of nature and visitors threatening the Galápagos, UNC researchers team with islanders to preserve this Pacific gem.

When Charles Darwin wrote his theory of natural selection, he probably never imagined the guava tree would sit atop the hierarchy. But in the Galápagos Islands, where Darwin observed the myriad of species that inspired his legacy, this plant is besting both man and beast.

Located 600 miles off the coast of mainland Ecuador, the Galápagos — also known as the Enchanted Islands — stretch over hundreds of miles of blue Pacific.

For most of its existence, this volcanic archipelago has remained the untouched sanctuary of some of the world’s most unique plant and animal life. However, with the arrival of humans, this fragile ecological balance was thrown off.

The first visitors to the Galápagos — explorers, pirates and whalers — made brief stops at the islands centuries ago and left goats, pigs and exotic plants behind as future food sources. Later, migrants from the Ecuadorian mainland and international settlers began to inhabit the islands, bringing guava with them as a source of fruit and medicines.

Descendants of the goats and pigs fed on the guava, the seeds of which remain whole after the rest of the fruit is digested. Gradually, the seeds were spread beyond the tree’s contained habitat, and guava began strangling the native and endemic flora and negatively affecting the island’s unique fauna.

With the introduction of agriculture on the islands at the start of the 20th century, the ecology of the Galápagos transformed again as farmers cleared stretches of land and expanded their settlements.

Today, the Galápagos are more accessible to the outside world, and a booming tourist industry has dictated development in the archipelago.

“Farmers who prefer to work in tourism because it pays more abandon the lands,” said Dr. Carlos Mena, post-doctoral student in the UNC-Chapel Hill Department of Geography and a native Ecuadorian.

These abandoned lands are a treasure trove of biological feed for invasive species like guava and the blackberry bush mora. And so, the native plant and animal life of the Enchanted Islands are being overrun by a growing population of humans and exotic and invasive plants.

“There is a synergy of mechanisms that work for the expansion of these invasive species,” Mena said.

This synergy of coupled human-natural systems — humans and animals, humans and plants, humans and fish — has slid under the microscope of Mena and Steve Walsh, UNC professor of geography and fellow at the Carolina Population Center.

“We realize the Galápagos have just been declared by the [United Nations] as a World Heritage site at risk,” said Walsh, “and they are at risk primarily from the increasing populations and the direct and indirect effects of economic development.”

The Galápagos have endured rapid growth both in the number of residents and in the number of tourists: in 2007, four of the 13 islands supported 36,000 residents and 150,000 tourists.

Walsh and Mena were invited to investigate the spread of invasive plants on the islands by the Nature Conservancy, the Galápagos National Park, the Charles Darwin Research Station and CLIRSEN, the Ecuadorian agency responsible for land use studies and remote sensing – gathering data about an area from a distance, such as satellite imagery.

“As a broad, comprehensive research university, UNC brings tremendous assets to the problems facing the Galápagos islands,” said Walsh.

However, he and Mena knew they would have to find UNC’s niche within the larger research community on the Galápagos.

Small and isolated, the Galápagos are a perfect laboratory for studying the environmental impacts of rapid development versus resource conservation. But few of the scientists swarming the islands have investigated the interactions of social, environmental and health aspects.

“UNC is complementing the existing expertise by emphasizing population-environment interactions and geo-spatial technologies,” Walsh said.

He and Mena began mapping and modeling the spread of invasive plants on three of the four populated islands — Santa Cruz, San Cristobal and Isabela — using satellite imagery combined with field measurements and demographic surveys.

In order to investigate his hypotheses about the link between the spread of invasive species and human activity on the islands, Walsh expanded the research team to include experts in demography, ecology, sociology, health and anthropology.

Their goal is to produce a model that will show the effects of alternative resource conservation and economic development scenarios on the Galápagos to inform policy decisions.

Toward this end, Walsh and Mena work with a variety of organizations, Ecuadorian and international.

“Our goal is to engage in research, education and outreach programs that will affect graduates, undergraduates, faculty and visiting scholars as we create collaborative partnerships with the University of San Francisco Quito, the Galápagos National Park and the Charles Darwin Research Station,” said Walsh.

The project has brought Walsh and Mena particularly close. The two work as a team and consider themselves interdependent.

Walsh and Mena have traveled to the Galápagos several times since 2006. They say that through their presence on the islands they are building relationships with the hopes of creating a true partnership.

“This project cannot be something placed in the Galápagos from the outside,” Mena said. “It must be something built together from the bottom up. It must be something from the community; it is not just science in a journal paper.”

Walsh and Mena are forming plans with the University of San Francisco Quito to develop a research center on Isabela Island, which will serve as a hub for their joint research and a host site for the student and faculty exchanges that they hope to coordinate between Ecuador and Chapel Hill.

“Carolina wants to be part of this, to be helping the well-being of people, to be helping unravel the conflicts between economic development and resource conservation,” Walsh said. “We want to be able to say that what Carolina knows and does has an impact on the archipelago, region and world.”

Though the Galápagos are a two-and-a-half hour plane flight from the Ecuadorian capital, Quito, and out of reach for the average Ecuadorian, they remain a great source of national pride and a resource to conserve, said Mena.

“When you go there you realize it is a very charismatic place,” he explained. “I know that others are going to live there, and I want them to enjoy the same places that I enjoyed.”