Along with the Broad-Faced Potoroo, the Flores Cave Rat, the Guam Flying Fox, the Japanese Wolf, the Syrian Wild Ass, and, oh yes, our pal the dodo, we can add the Caribbean monk seal, last seen in 1952, to the official list of extinct species. The U.S. government declared it so over the weekend, after five futile years without a sighting. Overhunting had done it in:

         

But what does one less species of seal really matter? Should anyone care? (See also Andy Revkin's question at the Times the other day: "Does the world need leatherback turtles? Most likely not.") One place to start in on this topic is with Julia Whitty's excellent Mother Jones piece from last April on the threat of mass extinction. Especially this:

A poll by the American Museum of Natural History finds that 7 in 10 biologists believe that mass extinction poses a colossal threat to human existence, a more serious environmental problem than even its contributor, global warming, and that the dangers of mass extinction are woefully underestimated by most everyone outside of science.

E.O. Wilson has predicted that roughly half of all plant and animal species will be extinct by the year 2100. There have been five great extinction waves in the past 439 million years. We're on the verge of a sixth, as "habitat degradation, overexploitation, agricultural monocultures, human-borne invasive species, [and] human-induced climate change" raise the rate of extinction to something like 1,000 to 10,000 times the background rate. (More recently, Joseph Wright and Helene Muller-Laundau have argued that the crisis isn't as bad as thought, although their work is controversial.)

Whitty's piece is very much worth reading, though I always wish these articles would hammer home why humans should care about the loss of biodiversity. It may be strange to say, but I don't think it's obvious to most people why it's a problem if entire ecosystems up and vanish. Newspapers have long reported the fact that bees are vanishing en masse, which could threaten $15 billion worth of U.S. agriculture. More concrete examples like this might, I think, get the point across. There's no equivalent to the IPCC for the extinction crisis—a body that could hammer out a consensus perspective and urge governments to take action. Why not?

Mind you, climate change is a solvable—though staggering—problem. I'm less sure anything can be done to halt what Stephen Meyer calls the "The End of the Wild" (Meyer isn't sure, either). Whitty discusses the Wildlands Project, which would create massive linked "corridors" for wildlife, on a scale larger than anything yet contemplated. In the United States, ecologically significant areas such as Florida, the Arctic/Boreal regions, and the Rocky Mountains would be preserved and connected (see that map on the right). But it's also an audacious project: Wildlands advocates estimate that the project could take 100 years or more—and by then, mass extinction will be well underway.

But there's definitely something to the Wildlands idea. Right now, wildlife preserves tend to be very small, and are often isolated from other wilderness areas, preventing the sort of migration that fosters biodiversity. These reserves are usually hemmed in by human activities—farms, urban sprawl, clear-cutting—that affect them, even if they have well-enforced boundaries. The Monteverde Cloud Forest Preserve, an eco-tourist hotspot which covers 30,000 acres and hosts thousands of species, has been drying out because of farming in the surrounding lowlands. And climate change could soon make the whole concept of a static, isolated preserve unworkable—monarch butterflies may soon find the biopreserves in Mexico where they winter uninhabitable, for instance.

Any serious attempt to stem the extinction crisis—even if it can't be stopped—would likely have to take a new approach to wildlife preserves. (As Whitty notes, even Yellowstone National Park has been bleeding biodiversity.) Meyer recommends setting up sites that protect "broad ecosystem functions... in a dynamic environment, rather than species-specific habitat needs or singly-defining (highly peculiar) ecological characteristics." Even if something like the Wildlands project can't be done, governments ought to be thinking bigger than scattered butterfly preserves if they want to preserve what they can of the world's biodiversity.

At the moment, though, governments focus mainly on saving individual species. This essentially amounts to man-made evolution: We decide which species get to stay and which ones go. Pandas are cute and need saving; thousands of insects and deep-sea invertebrates that sustain whole ecosystems get little thought. Indeed, the original idea behind the U.S. Endangered Species Act was that the causes of extinction were finite and only a handful of species were genuinely threatened. That notion seems quaint in the face of an impending mass die-off of species we don't even know about. Now, I don't want to see the ESA junked. Pandas really are adorable and need to be saved. But it's sort of like spitting in a hurricane at this point.

--Bradford Plumer