Tom Tomorrow Wins Herblock Prize!

[G_j]

64. It's been shown that wolves are GOOD for the ecosystem.

http://www.nytimes.com/2012/09/29/opinion/the-world-needs-wolves.html

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Many Americans, even as they view the extermination of a species as morally anathema, struggle to grasp the tangible effects of the loss of wolves. It turns out that, far from being freeloaders on the top of the food chain, wolves have a powerful effect on the well-being of the ecosystems around them — from the survival of trees and riverbank vegetation to, perhaps surprisingly, the health of the populations of their prey.

An example of this can be found in Wyoming’s Yellowstone National Park, where wolves were virtually wiped out in the 1920s and reintroduced in the ’90s. Since the wolves have come back, scientists have noted an unexpected improvement in many of the park’s degraded stream areas.

Stands of aspen and other native vegetation, once decimated by overgrazing, are now growing up along the banks. This may have something to do with changing fire patterns, but it is also probably because elk and other browsing animals behave differently when wolves are around. Instead of eating greenery down to the soil, they take a bite or two, look up to check for threats, and keep moving. The greenery can grow tall enough to reproduce.

Beavers, despite being on the wolf’s menu, also benefit when their predators are around. The healthy vegetation encouraged by the presence of wolves provides food and shelter to beavers. Beavers in turn go on to create dams that help keep rivers clean and lessen the effects of drought. Beaver activity also spreads a welcome mat for thronging biodiversity. Bugs, amphibians, fish, birds and small mammals find the water around dams to be an ideal habitat.

So the beavers keep the rivers from drying up while, at the same time, healthy vegetation keeps the rivers from flooding, and all this biological interaction helps maintain rich soil that better sequesters carbon — that stuff we want to get out of the atmosphere and back into the ground. In other words, by helping to maintain a healthy ecosystem, wolves are connected to climate change: without them, these landscapes would be more vulnerable to the effects of those big weather events we will increasingly experience as the planet warms.

Scientists call this sequence of impacts down the food chain a “trophic cascade.” The wolf is connected to the elk is connected to the aspen is connected to the beaver. Keeping these connections going ensures healthy, functioning ecosystems, which in turn support human life.

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