Taking the toll of warming

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"Affected species have three possible responses to global climate change," write Robert Sullivan of Argonne National Laboratory and Milt Clark of USEPA's Region V in the March issue of Chicago Wilderness Journal: "change, move, or die."

They admit they can't answer their article's title question, "Can Biodiversity Survive Global Warming?" because ecosystems are complex and different climate models predict different degrees of warming. But "it is believed that the net effects of global climate change will favor invasive species -- those opportunists that can quickly exploit the new ecological niches that will open up as native species ...cannot adapt.... The additional stresses on ecosystems (along with higher temperatures) will also likely favor vector-borne diseases such as the mosquito-spread West Nile virus that has devastated populations of many bird species in the Chicago area."

Dying is as easy as ever, but moving isn't. Roads, cities, suburbs, and farms have broken up habitats, so that "species that could once move long distances freely to seek more favorite habitat are now faced with numerous man-made barriers," increasing the invasives' advantage. "Habitat fragmentation also reduces the genetic pool from which species can draw to evolve new mechanisms to cope with change."

The article is heavily footnoted to the scientific literature, some of which is accessible on-line free, including a thorough 35-page 2006 review, "Ecological and Evolutionary Responses to Recent Climate Change" by Camille Parmesan of the University of Texas, who notes that "documented rapid loss of habitable climate space makes it no surprise that the first extinctions of entire species attributed to global warming are mountain-restricted species," specifically frogs in the Costa Rican cloud forests. On a mountain, the only way to stay cool is to move up, and pretty soon you run out of mountain.

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