Lend me a hand


The effects of global warming on plants and animals are likely to be as varied as the species themselves. Some will adapt; some will even benefit. But what does the future hold for those too slow-moving, slow-growing, or otherwise unable to make the best of things? Conservation biologists have been talking, many nervously and some less so, about "assisted migration" or "assisted colonization" -- in short, picking up vulnerable plants and animals and moving them to more hospitable climes.

Now, across the pond, a team of UK scientists have conducted the first formal test of assisted colonization: The biologists moved two butterfly species 20 to 40 miles north of the edge of their existing ranges in northern England, then watched and waited. Over six years, the new butterfly populations grew and expanded in these "climatically suitable" areas -- a result the study authors say bodes well for assisted colonization as a conservation strategy.

Lots of implications here for Western critters. The Quino checkerspot butterfly in northern Mexico and southern California is blocked by development to the north and unlikely to move on its own. And yesterday, the US Fish and Wildlife Service -- prodded by a lawsuit -- announced that it would consider Endangered Species Act protection for the American pika because of its vulnerability to climate change.

Of course, when it comes to assisted colonization, countless questions remain -- if we're going to move species, which ones? And how do we make sure we're not creating more problems than we solve?