Wild Tracks

On behalf of the world's wild species

Screwing With Ecosystems

Officials in Australia thought they had a good idea when they brought in the first cane toads. Various governments in Europe have eradicated their predators, and then complained bitterly when the rabbit population exploded.

Have we learned nothing?

States in the western USA are now contemplating the removal of the grey wolf from protection under the Endangered Species Act. Taking away this protection would mean ranchers could legally blast every wolf they see to kingdom come – something they really like doing.

If delisting does occur, Wyoming and Idaho have announced their intention to reduce wolf numbers by 50% and 80%, respectively. At present, there are an estimated 300 wolves in Wyoming and 700 in Idaho. That’s a wolf slaughter of 150 + 560 animals.

Wolves, or any other predators for that matter, do not exist in a vacuum. They have a purpose, and that purpose affects the entire ecosystem.

For starters, fewer wolves mean more coyotes. Researchers from the Wildlife Conservation Society working in Yellowstone followed radio-collared coyotes at both wolf-abundant and wolf-free locations. They found that while coyotes were more numerous than wolves in locations where the two exist, coyote densities were more than 30″% lower in areas they share with wolves.

The smaller coyotes apparently hold their own by living in packs. Transient coyotes without the support of a pack were more likely to fall prey to wolves, with 56% of transient coyote mortality being attributable to wolves.

Male pronghorn antelope

Male pronghorn antelope

Fewer wolves also translates into few pronghorn antelope. It seems one of the favorite prey species of the coyote is pronghorn lambs. The bigger wolves don’t spend much time hunting, what would be for them, a small snack. As a result, pronghorn fawns have higher survival rates when wolves are present in an ecosystem.

While pronghorn are not endangered, the population that summers in the Greater Yellowstone Ecosystem, was reduced to fewer than 200 animals in recent years. Since wolves were reintroduced in 1995, the pronghorn population has increased by approximately 50%.

This has all happened before. Officials somewhere decide to kill the wolves. A few years later, the same officials are crying because they are overrun with deer. So they decide to kill the deer. Then they discover their populations of wolf, bear, and other top predators are dangerously low. So they protect the predators again.

If humans would just stop screwing with ecosystems everything would balance itself out. Apparently, it’s not a lesson anyone has learned yet. At this point, I doubt if they ever will.


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