Unintended Consequences

February 25, 2005 12:09 PM

Cane toads in Australia. Zebra Mussels in The Great Lakes. Purple Loosestrife in Canada (and the introduction of another alien species to control it, I don't know why she swallowed the fly).

Invasive species, threat or menace? You decide.
posted by Capn (27 comments total)

Hey, don't knock invasive species. We are one:

'Invasive species are those which establish a population, reproduce rapidly, and displace native species.'
posted by driveler at 12:15 PM on February 25, 2005

In defence of the Zebra Mussel, it's made Lake Erie cleaner than it's been in about seventy years. IIRC, each one filters about a liter of water a day...not that they don't have their downsides.

Quoting:

Zebra mussels contributed to the improvement of Lake Erie's water clarity. Research shows that in the early ‘70s, water clarity was approximately 3 feet. It improved to 6 to 10 feet in the 1980s after a decade of reduced phosphorus inputs, and improved again to 10 to 17 feet in the early 1990s, after zebra mussels colonized the area.

That page also says their positive effects don't outweigh their negative effects (attaching themselves to other mussels, clogging pipes, dicing bare feet, etc).
posted by paul_smatatoes at 12:18 PM on February 25, 2005

Heehee, I knew somebody was going to do a cane toad FPP soon.
posted by Bugbread at 12:28 PM on February 25, 2005

It seems to me that's not much of a defense for the Zebra Mussel - they're eating all the nutrients that other more food-chain connected invertabrates otherwise would.

Improvement in water clarity isn't always a good thing. For example, acidified lakes are completely dead and crystal clear.
posted by anthill at 12:29 PM on February 25, 2005

I can't decide if they're a threat or a menace.
posted by notmydesk at 12:31 PM on February 25, 2005

I am not too proud to be cute bugbread. Also, crap, I spelled one of my tags wrong.
posted by Capn at 12:32 PM on February 25, 2005

Ha.
posted by redfoxtail at 12:35 PM on February 25, 2005

Cane toads are coming. They are fat, ugly and poisonous. They don't belong in Australia and they will harm our pets and native wildlife, but please remember they are still living creatures and feel pain too.

awww . . .
posted by hackly_fracture at 12:37 PM on February 25, 2005

I'm going with menace. Here is an example from a good overview of the problem:

The most destructive and most expensive transfer ever of an animal from one country to another was that of the European rabbit (similar to a cottontail) into Australia. It was introduced by a wealthy landowner, Thomas Austin, who had become homesick for the animals of his native England. Rabbits were not native to England either; they were introduced from Europe after the Norman conquest in 1066. Mr. Austin brought in a shipment of two dozen rabbits in 1859, and turned them loose on his estate in Victoria. They bred like rabbits, and provided some good hunting for Mr. Austin. Six years later he estimated that he had killed 20,000 rabbits and still had 10,000 left. They spread out across the continent, rabbit hunting became popular, and rabbit meat and fur became a major export for Australia. They did so well because their populations were not kept in check by weasels and foxes as they are in Europe. The only possible predators - the dingo and the Tasmanian wolf - were already being shot and kept in check by the sheep ranchers. And many of the rabbits' potential competitors, like kangaroos, were also being exterminated by the settlers.

In 50 years rabbits had spread all over Australia except the tropical regions in the north, and their populations were so dense that they would eat every blade of grass, and kill shrubs and trees by stripping them of their bark. They were denuding the sheep pastures of grass, turning once successful ranches into wastelands and reducing wool production by half. Finally they were declared vermin and were hunted, trapped, and poisoned. The government offered a bounty for rabbit tails, and millions were collected. But it is very difficult to catch every one. In 1902-1907 they built a 2,000-mile long fence, costing more than a million dollars, to try to stop the rabbits entering the cereal-growing area in the southwest. Rabbits starved to death and carpeted the ground with their bodies on one side of the fence, while the grass grew green on the other, for a while. Then a few rabbits got through and started the whole cycle again on the other side of the fence.

Today the "Rabbit Fence" marks a clear and straight boundary between the southwest, where all native vegetation was cleared to make way for agriculture, and the area to the east where forest still survives. This man-made alteration in the vegetation pattern is the most conspicuous man-made feature of Australia when viewed from space, and it appears to be causing a change in rainfall patterns.

posted by pracowity at 12:44 PM on February 25, 2005

Are these cane toads the same as the toads in Florida? I lived in Folrida a number of years ago when the toads were really start to spread across the state badly. A rumor had started that the poison they secreted would kill a dog but would give a person psychedelic visions. Numbnuts were catching frogs and licking them in an effort to get high.

Boa constricters are another introduced species in Florida. People buy them as pets and let them go when they get to big. Most other parts of the U.S., except Hawaii, this would not be a prob because the weather would kill them but the weather in South Florida is perfect for them. Their reports that anough of them have been let go out in the swamps that they are reproducing.
posted by berek at 12:46 PM on February 25, 2005

There's a tremendously awesome, laugh-out-loud funny documentary called Cane Toads: An Unnatural History. I can't recommend it highly enough. It's a little old (1988) but I don't think the situation has improved much since then.
posted by ssmith at 12:50 PM on February 25, 2005

Zebra mussels? Mere pikers compared to the Asian Carp...
posted by docgonzo at 12:51 PM on February 25, 2005

I live in Kalamazoo, MI, we've got purple loosestrife all over the place. I hate it. It's almost impossible to uproot. The weevils are sort of our only hope. Before the introduction of the weevils, we were going around and actually injecting each plant to kill the damn thing.

You can't imagine how bad the situation is. When you drive down the highway in the spring, all you see is purple, everywhere.

Somehow, I know the Republican party is behind this.
posted by Baby_Balrog at 1:02 PM on February 25, 2005

[this is good]
posted by Jim Jones at 1:06 PM on February 25, 2005

Hey - I think I saw this on Google.
posted by grateful at 1:06 PM on February 25, 2005

I dunno, this whole topic seems kinda made up to me.

Isn't this just evolution in progress? I don't see what difference it makes how a species moves from one place to another really, isn't it all part of the process? A new species comes along which is more adaptive to it's environment so it takes up residence to the detriment of some others.

Seems to me if an environment existed that was so advantageous for a big-old toad to flourish in then it was an opportunity waiting to be taken by some life-form or other. Isn't this just a case of the inevitable happening a little quicker, on an evolutionary timescale, than it would otherwise?
posted by scheptech at 1:16 PM on February 25, 2005

Mh nope not really we don't decide shit I think
posted by elpapacito at 1:17 PM on February 25, 2005

Never, EVER feed the Purple Loosestrife after midnight.
posted by dougunderscorenelso at 1:26 PM on February 25, 2005

scheptech:

I dunno, this whole topic seems kinda made up to me. Isn't this just evolution in progress? I don't see what difference it makes how a species moves from one place to another really, isn't it all part of the process?

*sigh*... yes. On a literal level, that is true. Of course it's analogous to the way that "everything that happens is the will of God" if you're a member of certain Christian strains. Yes, evolution will accomodate anything, and so anything other than complete annihilation can be considered "part of the process."

But evolution is a mean game. Remember, whatever practical advantages we might have, humans have no additional moral weight in the evolutionary process. And we really have a pretty narrow range of habitats that we can use -- warmer than, say, 30F, less than 120. Constant access to water, and constant access to energy (since we haven't mastered photosynthesis yet, that means lots of plants and, practically, animals).

Any sort of environmental concern is ultimately based on self-interest; certainly the earth could "survive" without us if we go full speed ahead, damn the torpedoes, on any environmentally reckless path. But will it be an earth that can support us? I suppose in the worst case we could all go underground and use solar/geothermal energy to grow hydroponic crops, and to hell with the surface conditions. But do you want to live out your life as a morlock? How about your grandchildren, or their grandchildren?

So yeah. Technically the "everything is part of nature" defense is true, but it's no more useful on that account.
posted by rkent at 1:34 PM on February 25, 2005

This is an extremely important issue.

First of all, Grey Goo.

ElPapacito, your comment makes no sense to me. In the same way that "barlsldkfgarb" makes no sense to me.

Scheptech, often times there exist barriers to migration that prevent certain life-forms from moving freely between climates that have encouraged vastly different forms of life to evolve. Consider small-pox and Native American cultures. If we don't do something about the lampreys and loosestrife in my area, we're going to lose our salmon, and we'll probably also lose a huge number of native plant species that are vital to a number of different ecosystems, like dune grass.
posted by Baby_Balrog at 1:36 PM on February 25, 2005

All others must bow to the mighty Phragmites. I do not remember seeing this plant befre the 1990s. Now it's in every roadside marsh in the northeastern U.S., it seems.
posted by gubo at 3:01 PM on February 25, 2005

Kent Brockman reads the news.

KENT
Our top story, the population of parasitic tree lizards has exploded, and local citizens couldn't be happier! It seems the rapacious reptiles have developed a taste for the common pigeon, also known as the 'feathered rat', or the 'gutter bird'. For the first time, citizens need not fear harassment by flocks of chattering disease-bags.

Later, Bart receives an award from Mayor Quimby outside the town hall. Several lizards slink past.

QUIMBY
For decimating our pigeon population, and making Springfield a less oppressive place to while away our worthless lives, I present you with this scented candle.

Skinner talks to Lisa.

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 unleash 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.
posted by Specklet at 3:12 PM on February 25, 2005

Nice quote, though from the wrong episode. I belive this fits the situation even better:

BART:
What does that sign say? ["Advisory: foreign florae and faunae prohibited!"] I thought they spoke English here!

LISA:
It says you can't bring in outside plants or animals. Any foreign creature you bring in could upset the environmental balance.

BART:
Oh. [removes toad from bag] Sorry, girl. I don't want to get into any more trouble down here. I'll pick you up on the wayhome. [puts it on the edge of a fountain]
posted by graventy at 4:28 PM on February 25, 2005

I have been thinking about Cane Toads lately. Cane Toads are ancient and universal, our ancestors put on Cane Toads to become an other, to become a god, even unto this day. Greek tragedy and comedy began in the worship of Dionysos, the god of wine, intoxication, and creative ecstasy, in rituals where worshipers often wore or worshipped Cane Toads. Indeed, the word for Cane Toad in Greek drama was persona, now commonly used to describe constructed online identities. And so we understand ourselves as wearing Cane Toads, whole series of Cane Toads--behind which we find only emptiness, for we can never see ourselves truly.

Capn is my hero.
posted by shmegegge at 4:52 PM on February 25, 2005

Gubo:
All others must bow to the mighty Phragmites.

I don't know, I think Phragmites pales in comparison to Kudzu.


Scheptech, you are right in that the success of an invasive species is just part of the evolution game. The issue is that the homogenization of nature is not beneficial for humans, or any other living thing. Once the biodiversity of an area falls below a certain level the habitat degrades and isn't able to support the number of species and individuals that it should. It also can't provide the ecosystem services, such as pollination and water filtration, that we humans rely on.

more info.
posted by amelliferae at 6:22 PM on February 25, 2005

Here's another one -- the dreaded Melaleuca tree, soaking up wetlands and growing faster than you can chop 'em down! It's more like a weed than a tree, really.

They were imported from Australia to South Florida by land barons, specifically to dry the pesky Everglades so they could sell more land and build more houses. That didn't really have the desired effect, but it did manage to start choking out all other plantlife. Look how densely they grow. They're nearly impossible to get rid of -- burning them spreads their seeds (if you can manage to burn them at all, since they're so waterlogged), cutting them is a losing battle, since it is said they can spread at the rate of an acre per day.

The current solution? Melaleuca snout beetles. Oy veh.

I could only find one use for Melaleuca. No, it's not the same species of Melaleuca that you can get the schmancy tea-tree oil from.
posted by contessa at 7:08 PM on February 25, 2005

...but please remember they are still living creatures and feel pain too...

That's why you should be careful to hit their head when you run them over. No, or very brief, pain.
posted by five fresh fish at 10:23 AM on February 26, 2005