One way to help species facing habitat loss: 'escape routes'

Preserving wilderness areas and establishing 'biological corridors' between them will help wildlife move to safety as climate changes occur.

from the June 21, 2007 edition

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At El Valle Amphibian Conservation Center (EVAC) in Panama, researchers recently succeeded in breeding the golden frog (not to be confused with the extinct golden toad), a species native to the area – and none too soon. Last year, the frog disappeared from the wild. "Chytrid came and basically gave the last blow," says EVAC director Edgardo Griffith.

Recent findings have raised some hopes of developing a chytrid vaccine, which could combat one cause of extinction. But scientists can't inoculate all of nature. Even if it were possible, the prospect quickly becomes prohibitively expensive when contemplating the mass extinctions predicted for the 21st century.

That's why some advocate "assisted migration," moving plants and animals before the climate changes too much.

This approach solves problems foreseen if natural selection runs its course in an unnatural setting. "If the only species that can migrate through disturbed habitat are weedy species, then those are the species you're going to get," says Jason McLachlan, assistant professor of biology at the University of Notre Dame in Indiana. These are the cockroaches, ragweeds, and jellyfish of the world, species that humankind generally finds neither useful nor aesthetically pleasing.

But moving species raises a host of sticky questions. What should an ecosystem that has never existed before in a particular place look like? What happens if the assisted species threaten the existing wildlife in their new location?

Despite many concerns, Professor McLachlan increasingly sees assisted migration as inevitable. "If elephants start going extinct because of climate change, people are going to move them," he says. "So the question is, 'What would be the effects of moving elephants to a new area? And how physically would you do it?' "

Any successful efforts to soften global warming's impact on wildlife will likely include a combination of tactics. But scientists see them as equivalent to an escape hatch or a backup parachute – a last-ditch effort. Except for corridors and reserves, these measure are not sustainable or cost-effective in the long term, they say.

The real solution is the most obvious, Pounds says: stop and eventually reverse greenhouse-gas buildup from human activity. And this fix ultimately depends on people. "If constituencies demand change, then you'll see that happen," he says.

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