The Loom

woodpecker-slide.gifOn Thursday I predicted that pundits would make the rediscovery of the Ivory-billed woodpecker an opportunity to criticise predictions that humans are causing mass extinctions–while conveniently ignoring evidence that goes against their claims. Today I came across the first case I know of, which appears a short Week-in-Review piece about the woodpeckers in the New York Times. (You have to scroll down a bit to the article.)

First, a conservation biologist is quoted saying that most things that scientists think are extinct are extinct. The article then ends with this:

But Stephen Budiansky, the author of several books on natural history, said the discovery points out how uncertain the business of predicting extinctions of species great and small – mostly small – can be.

All of the big numbers we have heard, of tens of thousands of extinctions worldwide, are not based on field observations," Mr. Budiansky said. "They’re based on very simplistic mathematical models. But there’s a huge gap between those predictions and the numbers of species we can actually confirm are extinct."

Budiansky’s name may be familiar to you, especially if you followed the link to a paper by Stuart Pimm I provided in the last post. In the early 1990s, Budiansky was one of the first people to float the idea that North American birds demolish estimates of the current extinction rate based on habitat loss. Budiansky didn’t actually make these claims in a scientific paper, but first in an article for U.S. News and World Report, and then later in a book, Nature’s Keepers. In the paper I linked to, Pimm explicitly cites Budiansky’s claims, and then proceeds to show that they are wrong. Fast forward some ten years. In that time Budiansky has, as far as I can tell from my search, never responded to Pimm’s paper in a scientific journal or magazine. Nevertheless, he’s still ready to hold forth about extinctions. I suppose he’s trying to be controversial, but from his quote, you’d think that conservation biologists made these mathematical models in some smoke-filled back room and kept them a sworn secret. But you just need to look at Pimm’s paper, or any other in this area, to see that they’ve always been upfront about using mathematical modeling to make predictions–just as a chemist uses mathematical models to make predictions about a chemical reaction, or a meteorologist uses models to predict the weather next week. But there’s also been a long tradition of fieldwork (and experiments) to test the assumptions of the model. As for the huge gap between predictions and numbers of species we can actually confirm are extinct, if Budiansky wants to bankroll the millions of field biologists who would be needed to track the fate of all the millions of species on Earth over the next 200 years, I’m sure no conservation biologist would complain. But until then, our knowledge will have to remain imperfect.

(For those who want more: 1. Stuart Pimm gave an interesting talk on all this a couple years ago, and the transcript and audio file are available here. 2. For a similar case of flimsy "skepticism" about extinctions, see this post.)

Comments

  1. #1 Henry Astley
    May 1, 2005

    What comes to my mind is “there are no white ravens”, in terms of the logical difficulties of studying extinction. You can easily prove that there *are* white ravens by finding one, dead or alive. But you can never 100% prove that there is no such thing, because it’s always possible that you missed it, or blinked at the wrong moment, or the albinism gene was entirely in a heterozygous state this generation, or somesuch. You can be 99.999% sure, but that takes a lot of effort, and you’ll never be truly 100% sure.

    You can’t ever really *prove* a species extinct, and spectacular returns from presumed extinction such as the ivory-bill or the coelocanth remind us of this. But at the same time, those are exceptions to the rule, and most species listed as extinct truly are dead.

    Still, most such pundits are products of the US public school system, can therefore can’t be expected, on average, to understand such things.

  2. #2 snaxalotl
    May 1, 2005

    “huge gap between those predictions and the numbers of species we can actually confirm are extinct”

    the bad smell here is the convenient inference people will make that this means the same thing as “huge gap between predictions and number of species which are extinct”. I can’t help but feel this is being deliberately suggested.

    of course, the best bet we have for those actual numbers is always going to be the best scientific model.

  3. #3 Timothy McDougald
    May 2, 2005

    Two things occured to me while reading the post. First, they “balanced” the opinion of a conservation biologist with an author of several natural history books as if they carried equal weight and had equal expertise in the subject.
    Second, they are deriding mathmatical models (shades of climate change contrarians) yet if there was no math involved how quick would they be to say it was unscientific. Seems to me like they are trying to have their cake and eat it too.

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