There goes the neighborhood
March 3, 2009 1:26 PM

Are there any species other than humans whose own success (at procreation, expansion, etc.) has threatened or ruined their habitat?

I'm not talking about species whose habitat we've ruined, or that we've hunted to extinction (like the dodo). I'm asking if there are any who've done it to themselves.

(Both plant and animal species count.)
posted by ocherdraco to Science & Nature (16 answers total) 4 users marked this as a favorite
All successful species change their environment. Whether that counts as "ruining" their environment is a value judgment, and nature doesn't make value judgments.

Elephants turn jungle into savannah. Beavers turn forests into meadows. Locusts wipe out their own food source and have to move on.

Generally species stop before their success destroys their environment because, at the margins, they stop being able to reproduce. Thus the Black Plague killed off enough human beings (and rats) in Europe that it ran out of susceptible non-infected humans; many diseases live only in reservoirs where they are endemic and non-fatal to animals. Had HIV arrived in an earlier period of history, it would have either wiped out all promiscuous human societies, or evolved to be less virulent.

There have been studies of, e.g. foxes and rabbits on islands. The foxes reproduce until they kill off too many rabbits. Then the fox population crashes. That causes the rabbit population to spike. That causes the fox population to spike, until the foxes kill off too many rabbits...

Nature is dynamic. Species are constantly evolving or going extinct. Human beings are just doing it much faster than nature can keep up.
posted by musofire at 1:34 PM on March 3, 2009


Every species that has ever existed has done this. There is a misunderstanding that animals are somehow magically in balance with nature, they are not. Balance comes from a series of population explosions that occur when a limiting factor is increased and crashes that occur when the population outstrips a limiting factor like food or space. If these population explosions are particularly dramatic, long-term damage that lowers the carrying capacity of the habitat in the immediate future will be done.

If you're talking about pollution this happens too. Bacteria, especially bacteria in a pure culture with no limit on their food supply grow until their waste metabolites cause the population to crash.

Humans are not unique or special in either of these regards.
posted by 517 at 1:39 PM on March 3, 2009


Arguably army ants do that. The reason that army ants are constantly on the move is that when they stop, they hunt the surrounding area out. With food exhausted they have to move on.

The ultimate fate of the pond behind a beaver dam is to silt up and form a meadow, which renders it useless to the beavers.

There's a species of vole that lives in Finland and NW Russia whose population follows a multi-year cycle of boom and bust. They are prolific breeders, and despite a large population of predators (mostly foxes and owls) they ultimately exceed their food supply. Then most of them starve and the population collapses.

Elephants like to uproot and eat trees; it's a major source of food to them, and they're strong enough to do it. That's been quite a problem in some areas of southern Africa, which have largely been deforested by elephants.
posted by Chocolate Pickle at 1:44 PM on March 3, 2009


You know, I think I have hilariously asked the biological equivalent to the language change question I shot down last week.

That one was "Language changes constantly."
This one is "Nature changes constantly."

How bout that. Thanks for pointing out my biased questioning. Will try to look at these things more rationally in future.
posted by ocherdraco at 1:46 PM on March 3, 2009


Maybe not quite on point, but lots of parasites kill their hosts.
posted by mhum at 1:55 PM on March 3, 2009


For a super crazy example of this sort of thing check this out.
posted by jeb at 2:00 PM on March 3, 2009


I just answered your question directly, and now I'd like to talk about the subtext I infer from your question. (And your post title.)

As others have said, the idea of "Man, the raper of Mother Gaia, without whom everything would exist in peace and harmony" is bunk. If you think humans are brutal, you ought to watch film of African wild dogs catching and killing a wildebeast. A couple of the dogs will attach themselves to the head and tail of the gnu and hold it down, and the others will disembowel it and start to eat it while it is still alive. (Somewhere during the process, of course, the poor thing does die, but only after suffering terrible agony.)

The usual fate for animals in the wild is violent, painful death.

For a long time there was a dogma among naturalists that pristine ecosystems were invariably in equilibrium. Now it's known that's not the case. There are a lot of ecosystems that are chaotic, which over the course of multiple years ring like a bell -- and never stop ringing. The one I mentioned about rodents in Finland has been oscillating as long as anyone knows and seems inherently resistant to settling into any kind of equilibrium state. The problem is that the rodents are too efficient at breeding.

This is akin to the "Noble Savage" romanticism, and just like that particular wrong idea, this impression, that nature is gentle and beautiful and and in balance until humans come along and upset the apple cart, is an article of faith in some quarters that approaches religious dogma.

And it's bunk.
posted by Chocolate Pickle at 2:05 PM on March 3, 2009


Humans are not unique or special in either of these regards.

Except that we have the power to see the ends of our actions, are changing the world much faster andto a greater degree than any other animal has done and most importantly we have the power to change it.
posted by crewshell at 2:05 PM on March 3, 2009


My question is coming less from the whole noble savage thing, and more from "If we can pretty clearly see that we're making our own habitat unworkable for us, why do we keep doing it?" and "If we behave in this shortsighted way, other species probably do it, too. I've never thought about that before." (I was pondering recycled toilet paper at the time, and why we don't use it nearly as much as we use the fluffy, less good for the environment kind.)
posted by ocherdraco at 2:09 PM on March 3, 2009


The bottom line is that in order for our alteration to the environment to drop to a level where nature could recover from our effects at the same rate we cause them, the human population would have to be reduced by the order of billions.

So clearly we should draw lots on who's going to carry on the human race while the others go to the soylent green factory. Who's first?
posted by fearnothing at 3:29 PM on March 3, 2009


Smallpox. It's not wise to piss off your environment if it's smarter than you.
posted by edd at 3:58 PM on March 3, 2009


The points made by musofire and 517 used to be taught in grade school science.

I remember the wording to be, "Every organism will alter its environment until it becomes toxic to it." And, to my great surprise, my biologist niece had never heard this before.
posted by trinity8-director at 3:59 PM on March 3, 2009


Oh, and the corollary (which I just remembered) was, "Only man has the ability to alter his behavior to prevent that."

I can just imagine the hate-humans-first enviro's writhing over that one.
posted by trinity8-director at 4:02 PM on March 3, 2009


An example where this happens is in brewing: the yeast in whatever you're brewing (beer, wine, etc.) eats the sugar you've added and excretes alcohol. If the alcohol level in the liquid becomes too high, the yeast dies from its own waste products. (This is why it's difficult to produce fermented drinks with greater than 15% alcohol or so--usually the alcohol has to be distilled to be more concentrated.)
posted by Upton O'Good at 7:42 PM on March 3, 2009


"Except that we have the power to see the ends of our actions, are changing the world much faster andto a greater degree than any other animal has done and most importantly we have the power to change it."

Not really, to both of those ideas.

First, humans do not possess the ability to intentionally stop some behaviors on a species level when those behaviors are profitable. (See the war on drugs, current environmental problems, genocide, slavery, etc.) So regardless of our ability to recognize a problem and identify its cause, we can't modify our behavior in response to the new information. So how do we know that at a species level we are able to recognize the ends of our actions? I would argue that we don't yet have that ability.

Second, the evolution of photosynthesis changed the atmosphere so dramatically a new basic division of life had to evolve to deal with it, the aerobes. Humans are never going to touch the scope of changes that bacteria and plants hath wrought upon this planet. Not even in their wettest dreams.
posted by 517 at 8:43 PM on March 3, 2009


The points made by musofire and 517 used to be taught in grade school science.

I remember the wording to be, "Every organism will alter its environment until it becomes toxic to it." And, to my great surprise, my biologist niece had never heard this before.


And so obviously, the thing that you were taught in elementary school is right and your niece, trained as a biologist, is wrong. What a bizarre conclusion.

nature doesn't make value judgments

I'd say that death without reproduction, on the level of the individual, and extinction, at the "species" level, is a pretty serious value judgment.

Sorry, this thread is whack. The idea that "humans are degrading their environment" is just an anthropocentric, like, value judgment man is true, but such an argument simply wouldn't fly in the other 99.99% of life. Good record you're listening to? You think the earth gives a fuuuuuck if you like it? That dude killed 33 people and was acquitted? Meh, things die in nature all the time!

Regardless what half-assed poststructural arguments people are trying to make, I'd defy anyone to come up with a species that was so successful at altering its environment that it caused its own extinction.

Chocolate Pickle offers up some fairly good ecological phenomena, but none of them result in the death of the species involved. Notice that in all those examples, the individuals (or their descendants) move on. Because they've evolved under certain constraints that allow for cycles -- some extreme -- to occur. Basically, people are right in saying that there is instability across nature, but that nature is in some ways self-correcting. Nevertheless, apart from rare and dramatic asteroid events, what's going on with humans is unprecedented in both speed and scope.

Yes, it's true. Life will survive on this planet far longer than we will. But to take that fact and then argue that what we're doing to our planet is no big deal, or that nature makes no value judgments, is so patently absurd and easily reductive that it shocks me how often it comes up on Metafilter. Take a step back and think about your grandkids for two seconds. Life has been playing out an insane mathematical experiment for four billion years, and a forum full of computer geeks can't even appreciate the fact that we're crashing it before we can understand it.
posted by one_bean at 10:43 PM on March 3, 2009


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