I know an old lady

I know an old lady who swallowed a cow
I don't know how she swallowed that cow …

I'm fascinated by stories of exotic invasives — those surprisingly adaptable foreign species like kudzu or the cane toad whose proliferation in a new ecosystem can have devastating consequences.

… She swallowed the cow to catch the dog …

A few years back I had dinner with a fellow who worked as a biologist for the state of Florida. He was working specifically on the problem of the melaleuca trees that are choking out native vegetation in the Everglades. As such, he was an expert on the potentially disastrous consequences of importing exotic species, even with the best of intentions.

His plan for dealing with the infestation of melaleucas, however, involved just such an enterprise. The problem in Florida, he said, was that the trees did not have to contend with any of their native predators. He advocated the importation of an Australian beetle — the melaleuca snout beetle — as a means of curtailing the spread of the trees. (This plan has since been adopted, as National Geographic reports.)

… She swallowed the dog to catch the cat …

So, I asked him, the solution to the problem of invasive exotics is to introduce more invasive exotics? Aren't there a million ways this could go wrong? He recognized the potential for unforeseen and unintended consequences, but, he reassured me, they had studied this carefully and were confident they could account for all the variables.

… She swallowed the cat to catch the bird …

I hope he's right. I hope the plan works and the snout beetles (and now psyllids, a second aphid-like Australian foe of the melaleuca) succeed in saving Florida's ecosystem from the trees from Oz without further complications. And I hope that, as the biologist assured me, the foreign insects will simply die out once their supply of melaleuca is diminished.

But what if they don't? What if we're not quite as in control of the situation as we like to think, and the snout beetles tastes adapt to their new surroundings?

… She swallowed the bird to catch the spider
Which wriggled and jiggled and tickled inside her …

The biological and ecological conundrums posed by exotic invasives have parallels in the world of foreign policy and international relations. There too, today's solution may become tomorrow's pest. Yesterday's friend may become today's foe.

… She swallowed the spider to catch the fly …

Here too, the experts assure us that they have considered all the variables — that they do not foresee or intend any unforeseen or unintended consequences. Yet here, too, I worry that there are more variables in play than we can account for — that we have not fully considered what might happen if this doesn't work, or even what might happen if it does.

… And I don't know why she swallowed the fly
Perhaps she'll die.

This chaotic multiplicity of variables and the inevitability of unintended consequences does not mean, of course, that we must passively do nothing. Neither melaleuca trees nor tyrants should be allowed to prosper unchallenged. But we do have a responsibility to ensure that our proposed solution does not wind up making things worse. We cannot forever continue the cycle of importing exotic species to counter the effects of the exotic species we imported.

I know an old lady who swallowed a horse …

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  • Eli

    Obligatory Simpsons reference!
    [Bart has unwittingly released a plague of bird-eating lizards into Springfield. But, as the Mayor and Principal Skinner explain, the lizards have saved the town from a plague of pigeons…]
    Skinner: Well, I was wrong. The lizards are a godsend.
    Lisa: But isn’t that a bit short-sighted? What happens when we’re overrun by lizards?
    Skinner: No problem. We simply release wave after wave of Chinese needle snakes. They’ll wipe out the lizards.
    Lisa: But aren’t the snakes even worse?
    Skinner: Yes, but we’re prepared for that. We’ve lined up a fabulous type of gorilla that thrives on snake meat.
    Lisa: But then we’re stuck with gorillas!
    Skinner: No, that’s the beautiful part. When wintertime rolls around, the gorillas simply freeze to death.

  • Dan

    Sigh. Because the Australian experience with the Cane Toad, and the Southern experience with Kudzu, and the Hawaiian experience with Mongooses, really were exceptions. Right.

  • Jon H

    Or the European Starling, which was introduced in the late 1800’s by someone who thought Central Park should have all the animals mentioned by Shakespeare.

  • none

    I nearly planted a bunch of melaleuca trees in Senegal when I was a Peace Corps volunteer there. It was sold to me as a near panacea for the deforested country, but the people there weren’t interested when I told them that the leaves were somewhat toxic to nonruminant species.

  • rdb

    While I can appreciate your concerns, they seem to be based on the assumption that the ecologists
    involved haven’t learnt from the continuing disaster of the cane toad and other failures.
    As an Australian, I have to rely on the competence of the CSIRO ecologists who look for host specific biological control agents to the many plants and animals that have become pests, invading both farmland and the bush. Mimosa in the top end, bridal creeper, Patterson’s curse aka Salvation Jane.
    The acclimatization societies brought out many English birds and animals. Foxes & cats have pushed many of the small native animals to the brink of extinction or beyond. Foxes may now be in Tasmania.
    I think we now have fire ants from improperly cleaned earth-moving equipment and Tasmania now has bumblebees from somebody who’s smuggled them in for better pollination of some crops.
    Rabbit Calicivirus has been the most contentious agent recently released – accidentally from an offshore island – but then probably deliberately spread by some farmers.

  • Glenn Condell

    what about the Indian mynah bird? Aggressive little buggers.
    All the best for 04 Fred.

  • Alan

    The prickly pear came with the First Fleet in 1788 to support a cochineal industry. It acclimatised and made same regions of the continent ungrazaeable. Then the cactoblastis beetle was introduced to control the prickly pear. The prickly pear infestation improved but the beetle also east sugar cane. We brought in the cane toad to eat the cactoblastis.
    Cane toads flourished almost as well as Australians. The native frog population is almost gone from toad-infested areas and the cane toad (now often a 1 kilo monster) is colonising the entire continent.
    Biocontrol may sound clean and green, but it’s results are often a catastrophe.
    PS 1788 is a long time ago now and we still don’t have a cochineal industry.

  • Alleged Idiot

    how about old fashioned, pull it by the roots removal? haha
    Imagine a few million floridians to get out their with their chain saws (this would be a great Jeb Bush PR Stunt for his future US Presidency). I can picture all those retires having something to do, and the occasionial news report by slacktivist saying “alleged, 20 ft gator swallows a 65 year old eco-lady who was swallowing invasive melaleucas trees.”

  • Dr Pedant

    Australia. Rabbits.

  • rdb

    Cane toads weren’t introduced against the cactoblastis beetle. Cactoblastis is still valued against prickly pear.