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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.

By Moises Velasquez-ManoffContributor to The Christian Science Monitor / June 21, 2007

Biolley District, Costa Rica

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.

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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.