2012年2月1日水曜日

What Can We Do To Save Pandas From Extinction?

what can we do to save pandas from extinction?

On the necessity of pandas « The view from Helicon

A friend asked for my thoughts on this article a while back (while my internet access was fairly limited). Here they are!

The idea of "conservation triage"—choosing which endangered species to protect/rehabilitate based on both their risk of extinction and our ability to save them—has been kicking around for a while. But I seem to have heard about it more lately, and specifically in the context of pandas.* Pandas are notoriously difficult to breed in captivity and inhabit a very narrow, and increasingly rare, habitat type. There's a good bet that even without human-induced habitat destruction, they'd have gone extinct due to demographic stochasticity (their populations were never large and they reproduce slowly, so by chance they could easily have experienced a population crash) or habitat loss due to natural climate changes. In fact, perhaps human intervention has already prolonged their tenure on this planet. Are we, by continuing to invest money and zoo space in panda conservation efforts, wasting our time on a doomed species, and worse, redirecting funds from species that actually could be saved from extinction? Are some species not worth saving?

The problem with this debate is that pandas are a red herring. They've become conservation emblems. People love pandas, so (I suspect) any panda exhibit in a zoo is automatically cost-effective by virtue of the extra visitors and merchandise sales it brings in. Even if, in the future, pandas only exist in zoos, they'll probably pay for their own upkeep.

There is nothing wrong with using furry, charismatic species as rallying points for conservation. In fact it can work quite well—many such species require large wild spaces in order to thrive, and providing this sort of habitat automatically makes room for many smaller, perhaps equally endangered species that share that ecosystem. So let's consider a hypothetical triage situation—not a panda, but, say, a small fly. Let's say it's as rare and as difficult to raise in captivity as a panda, but certainly far less cute. Let's say, further, that its impact on its ecosystem is minimal—not irrelevant, but it's not a keystone species either—its loss won't completely ruin the ecosystem. I personally think that said fly is as "valuable" in vague treehuggery moral terms as the panda. But I know as well as any biologist that funding is limited and that using those funds to stave off this fly's extinction is also hastening the demise of other flies (and mosses, clams, sea cucumbers…) that do have a chance. There's a strong argument for leaving this little fly to its doom.

There are still a few objections: we never know whether, in losing our poor fly, we're also losing a potential cure for cancer, AIDS, malaria, etc. This is another factor that has to go into the triage equation. But I'd argue that there's a point at which the resource drain of trying to save a "lost cause" species outweighs this hypothesized benefit. (Furthermore, if it's that hard to raise in the lab, it's going to be tricky getting any research material.)

Okay, so hypothetically we should triage species. But determining where to draw the lines is going to be extremely difficult. Take cases like the California condor and echo parakeet, which, while still endangered, have made astonishing recoveries (from a nadir of ten individuals for the parakeet and from 22 for the condor) due to concerted, dedicated human intervention. Which brings me to another point: there's a strong emotional factor in the triage equations as well. As soon as you say something's too rare to save, you'll probably find a few people who are willing to try.

I would thus advocate some pretty strict parameters: only the truly lost causes, i.e. less than one breeding pair left for sexually reproducing organisms, should ever be "rejected". But I must hedge even further: it's really, really hard to tell if a species is a lost cause. Especially if it lives somewhere remote: who knows if we've overlooked a few individuals? We hear of "rediscovered" species that were thought to be extinct on a fairly regular basis. While remoteness may favour survival, sometimes a captive-breeding intervention is the only thing that will allow a population to recover (see again the California condor).

Finally, what if we don't have enough resources to "treat" all these borderline cases? One possibility is to focus on the species that are most evolutionarily unique. This way, we'd preserve the maximum genetic (and phylogenetic) diversity. In a way, it would be an attempt to take a representative sample of earth's species from across the tree of life. Conservation biologists have been trying to develop guidelines to this end. One implementation of this approach is the EDGE of Existence project. It's currently identifying species that meet the criteria of "Evolutionarily Distinct and Globally Endangered" as a way to direct conservation resources towards species that need them the most. In fact, if you have a bit of money to throw around, I would highly recommend donating to this project.

*There is in fact a book called "Do We Need Pandas?" on my to-read list.

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