Wolves: Yellowstone’s missing link

Figure 1 Animals and plants depend on each other for survival. Every living thing has its place in a balanced ecosystem. Wolves are top predators, and when they disappeared from Yellowstone, the whole balance of the ecosystem was disrupted, affecting even the smallest creatures. This top-down, knock-on effect is called a trophic cascade

In the USA, there is a wild and beautiful place, spanning 9000 km2and sprawled across the states of Wyoming, Montana and Idaho. There are snowtopped mountains, boiling hot lakes, bubbling pools of mud, dramatic canyons, huge waterfalls, dark lakes and dense forests. Designated the world’s first national park in 1872, Yellowstone is home to a huge diversity of wildlife. Elk and bison roam the plains and it is the perfect hunting ground for bears, coyotes and wolves. But it has not always been this way.

Wolves have been a source of conflict with landowners, farmers and hunters since the late 1800s. Wolves were snared for their warm fur and shot if they chased or killed livestock. The wolves’ crucial role in the balance of the ecosystem of Yellowstone was not recognised, and their killing of prey animals including elk and deer was seen as destruction of more desirable species. Predator control was enforced by the US government in Yellowstone in the late 1800s and wolves had vanished from the park by 1926.