Fire-Ant Invasions Are Ecological Karma

Fire-Ant Invasions Are Ecological Karma

Fire-Ant Invasions Are Ecological Karma

If humans didn't make it so easy for them, invasive fire ants wouldn't invade.

So concludes one of the first experimental tests of the hypothesis that invasive species are not uniquely superior to local species, but take advantage of ecological niches opened by human disturbance.

It's a lesson people would do well to learn.

To test the idea, Florida State University biologists added fire ants — the stinging scourge of southern shopping malls and subdivisions — to forest plots that had been mowed and plowed.

Plowing destroyed existing ant colonies, and fire ants soon thrived. But when introduced to undisturbed forest, they couldn't find a foothold.

"Fire ants are 'passengers' rather than 'drivers' of ecological change," wrote the researchers in a paper published Monday in the Proceedings of the National Academy of Sciences.

They dubbed the ants "disturbance specialists," and suggest that other species may also specialize in disturbance.

Understanding this is "critically important," because human activity affects most of the Earth's surface.

But what can be done about it? Humans aren't about to stop developing land — but perhaps we could do so a little more carefully.

Experimental evidence that human impacts drive fire ant invasions and ecological change [PNAS]

Image: A sidewalk fire-ant nest in Tallahassee, Florida / Walter Tschinkel

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