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Save the Predators, Save the World

August 19, 2009

Predators—defined by one online source as “someone who attacks in search of booty”—get a bad rap. They’re viewed as bad-ass vermin who could kill or steal a baby at the drop of a hat. No one likes a killer or a baby-stealer, but what if all that killing, baby-stealing (and booty-hunting?) could save endangered species?

Since the 1960s, a 3,000-mile long wire fence has barred dingoes (the alleged baby-stealers) from the southeastern corner of Australia. The fence is supposed to keep the predatory dingoes away from sheep and other livestock on the other side. It’s worked. There’s now a dingo-free section of Australia and a dingo-ed section—and they are two very different areas.

In the dingo-free area, there are lots of mid-level predators like kangaroos and foxes, but not so many small mammals like mice and Tasmanian devils. On the other side of the fence, dingoes eat kangaroos and foxes, keeping the mid-level predators in check and the overall biodiversity much higher.* That’s a good thing—such a good thing, in fact, that scientists predict that 16 of the 19 threatened mammal species living in the dingo-free area would have a better shot at survival if they shared their turf with a few dingoes.

That’s not such a crazy idea, ya know. In the 1930s, gray wolves vanished—were killed off, actually—from Yellowstone National Park. Without wolves, the elk population flourished and became rather sedentary. While they reveled in their freedom from their fiercest winter predator (the wolf), the elk chowed down on young willows, cottonwoods and aspens. The lazy elk did a doozie on the trees, leaving little for willow-dependent critters like beavers to work with. And so, without the wolves to chase the elk, the beavers were screwed.

Now that wolves have returned to Yellowstone, the elk have stopped loitering and the beavers are back in business. (When Yellowstone was wolf-less there was one beaver colony in the park. Now there are nine.) The thriving willows provide habitat for songbirds and fodder for the multitude of beaver dams that now occupy streams throughout the park. Those beaver dams obviously provide habitat for beavers, but they also provide cool waters for fish. Now, just because wolves have put an end to the lolly-gagging elks, Yellowstone offers a plethora of habitat possibilities and a whole lot of biodiversity.

Dingoes and wolves are awesome, but we can’t discount the impact of every young man’s favorite predator, the one who may in fact be “in search of booty”—the cougar. When the National Park Service started developing the area around Zion Canyon in the 1930s, cougars split. Without cougars, mule deer started gobbling up the cottonwoods that lined the streambanks. Those cottonwoods had held the streambanks in place and provided shade for wetland plants, wildflowers, amphibians and butterflies. Now, the streambanks are eroding and the plants and animals that depended on the shady trees are declining. The lesson here is simple: a healthy ecosystem needs to have a few cougars on the prowl.**

*High biodiversity is a good thing. For a refresher on the importance of biodiversity, go here.

**Yes, I did just write that. No, I’m not a cougar.

2 Comments leave one →
  1. August 19, 2009 9:58 am

    excellent post!

    I’ve had to explain this to many people over the years, concerning marine top predators… sharks and mammals… Yes marine mammals are “cute” (I hate the use of that word!) and all that, but they’re really important because they help regulate their ecosytems! Ditto sharks! And is it the shark’s fault if we look like yummy seals to them? lol!

  2. Kelsey permalink*
    August 19, 2009 2:04 pm

    Thanks for the comment, crazycris! You might be interested in our previous post about the importance of sharks:

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