Creating 'escape routes' for wildlife

Biological corridors, such as one planned from Panama to Mexico, would let species migrate to safer climates as global warming heats up their old habitats.

Slightly smaller than West Virginia, Costa Rica is a relatively little country. At its narrowest, it's a mere 74 miles wide. And yet, like much of Central America, it contains an extraordinary diversity of wildlife. The country encompasses mangrove swamp on the coasts, lowland rain forest on the Caribbean coastal plain, drier forest in the foothills of the Pacific slopes, and high-elevation cloud forests on its mountains. Covering only 1/10000th of the world's surface, Costa Rica hosts 1 out of every 20 species on the planet. All of Central America hosts roughly 1 out of every 8 species.

As the globe warms, scientists generally expect ecozones – those habitats defined by a specific temperature and rainfall – to move away from the equator and, in mountainous regions, to move uphill.

In theory, the wildlife accustomed to these habitats would move, too. But in human-dominated and fragmented landscape – and given the speed of predicted climate change – scientists worry that wildlife won't be able to adjust in time. Trapped behind agricultural fields, cities, and highways, many species will simply disappear as the climate warms, they say. One-quarter of Earth's species – plant and animal – could disappear by century's end, according to the latest report by the Intergovernmental Panel on Climate Change.

To improve the situation, scientists propose creating "biological corridors" between wilderness areas – natural spaces that allow wildlife to shift uphill or across latitudes in response to changing climate. In Central America, conservationists dream of a paseo pantera – a panther's path – running from Panama north to Mexico. They call it the Meso-American Biological Corridor.

Facilitating the movement of wildlife isn't a new idea. Scientists have long argued that "corridors" would allow animals like the jaguar, which needs about 15 square miles of territory per individual, space to roam, hunt, and breed. Corridors also prompt the exchange of genes between isolated populations, promoting genetic diversity and avoiding inbreeding. (Unfortunately, they provide little help to animals on top of tropical mountains, which have nowhere to go.)

Making people part of the solution

But people often live where conservationists would like to put corridors, leaving two options: Remove the people and return the land to nature; or leave the people and work with them to make the land able to serve as a corridor.

Governments and conservation organizations usually don't have the money to buy land outright. And many think that removing people from the land creates a new set of problems. Landless people who are poor and desperate are much more likely to hunt and harvest in a destructive way, leading to more environmental degradation.

"Conservation is not only a technical or political process," says Bernal Herrera, science director of The Nature Conservancy's Costa Rica program, "but also a social process. You have to provide an alternative."

Conservationists working in southwestern Costa Rica hope to connect the country's largest national park, La Amistad, which sits on the central mountain chain and extends into neighboring Panama, with a lowland jungle on the Pacific coast called Osa. If the areas are connected, it would represent a significant link in the greater Meso-American Biological Corridor.

Rather than buying land and removing people, they've opted to promote organic coffee-growing methods along La Amistad's western flank. Coffee plants need shade, which means keeping trees – and wildlife habitat – throughout the plantation. And if the coffee is grown without pesticides, the plantations will also host many other plants, which in turn support a whole range of species. Many animals needing to shift their range in response to a changing climate could move through the area.

José Antonio Vargas Monge, president of ASOPROLA, an association of organic coffee growers in the area, has a lot to say about the joys and difficulties of his work. As he talks, his calloused hands move quickly over the coffee bushes, pruning green waxy leaves he calls hojas falsas – "false leaves."

Coffee plantations that switch to organic methods take three years to adjust, he says. Accustomed to direct application of fertilizer, the plants' root systems are not as extensive as they should be and must expand. The harvest inevitably declines. Unable to make the transition, some plants die. Many farmers despair and return to their old methods, which involve herbicides and pesticides.

But if the farmer can persevere through those initial years, the benefits are manifold, says Don Antonio, as his colleagues call him. The farmers and their families no longer expose themselves to pesticides. And although the organic plants produce fewer beans, they fetch more on the market. He pulls back the black, rotting leaf litter beneath a guava tree exposing coffee bush roots just beneath the surface. "It turns into something beautiful," he says.

Adding tourism to the mix

ASOPROLA has bigger plans than just roasting and selling organic coffee. Farming organically and sustainably has made the district into a tourist destination as well. Tourist dollars further diversify the incomes of farmers, making them less beholden to fluctuations in the coffee market.

Together, organic farming, La Amistad park, and tourism have another beneficial side effect, explains Yendry Suárez, vice president of ASPROLA. "Before, the young people migrated to the city to study, to work. Now, many of us young people have the opportunity of not leaving, of finding an income source locally," she says. "Here where we grew up – right here we're going to develop as people."

By involving communities that border La Amistad, park rangers increase the number of eyes and ears guarding it, says Gravin Villega Rodríguez, a ranger at La Amistad. Before, rangers would drive many hours in response to fire calls only to discover that a wily poacher had cried "fire" as a decoy. Now, with communities involved, when a ranger gets a fire call, "we can trust it," Mr. Villega says. More often than not, members of the community "put it out themselves," he says.

Many conservationists hail organizations such as ASOPROLA as a key to both creating wilderness corridors and preserving existing parks. But some doubt the long-term effectiveness of this type of conservation. A farmer may agree to reforest his land or adopt sustainable land-use practices today, says Daniel Janzen, a technical adviser to Área de Conservación Guanacaste, a park in Costa Rica's northwest. But what happens if tomorrow his daughter gets married and needs a house, or the next generation takes the land over and doesn't feel the same way?

"Bye-bye forest," suggests Dr. Janzen in a phone conversation.

The best way to preserve biodiversity – and bolster many species' chances of surviving in a warmer world – is to consolidate and expand existing parks, and endow them to exist for the foreseeable future, he says. "All the private efforts we do are temporary," Janzen says. "The only things that will be here 1,000 years from now are the governments."