Keystone Species and Their Role in the Environment

The wolf will probably always be a predator on the brink of extinction. Because of rumors, tall tales, false accusations and fear, wolves aren't welcomed on their native land. They are in direct competition with ranchers and hunters for space and food. The wolf was reintroduced to Yellowstone for one very important reason. They are one of the keystone species that maintains the balance of nature in an ecosystem, which in turn helps to keep habitats healthy. Plants and animals in the natural world go extinct periodically, but when man tries to hurry that process by eliminating a keystone species, we are risking the health of ecosystems and possibly; our own survival.

University of Washington professor of zoology, Robert T. Paine, conducted a scientific study of the starfish, a keystone species, over a three year period to determine what would happen to an ecosystem if a predator was removed from a habitat. In 1969, Professor Paine introduced his findings proving how an ecosystem is damage when a predator is no longer present.

Why keystone species are important

In architecture, a keystone is a wedge shaped stone at the top of an arch that locks in place all of the other pieces. Without a solid keystone, the arch would never survive. In nature, a keystone species is the one animal or plant in that ecosystem that maintains a healthy natural balance. The gray wolf is a perfect example of a keystone species. Starfish, beavers, salamanders, sea otters, alligators and elephants are also keystone species.

The health of Yellowstone's ecosystem before the 1995 reintroduction of the wolf

The wolf is an apex predator which means they sit at the top of the food chain and have no other predator to fear; other than man. Without the wolf, the ecosystem was on a downward spiral. This keystone species had been eliminated from Yellowstone in the early 1920's. One change in the environment that was noticed almost immediately was a declining population of Aspen groves. Scientists knew something was wrong, but they didn't understand what the problem was until they began to understand the wolf's role in the ecosystem. Elk populations had swelled when they no longer had to worry about wolves lurking around. With the wolf out of the picture, grazing animals stayed in one place and overgrazed, eating Aspen shoots before they could mature. An Aspen grove is made up of individual trees. New trees grow from shoots, not seeds, and the trees are all connected by a single root system. The oldest grove is around 80,000 years old and is located in southern Utah.

Cottonwoods and willows had deteriorated to the point where songbirds had left the area. Streams lost beaver, fish and amphibians. Birds and other animals that are scavengers were having a harder time finding food with no wolf kills to feed off of.

Trophic cascade

Trophic cascade is a theory scientists use to understand how everything in an ecosystem is intertwined with each other. It means that a predator, like the wolf, affects all wildlife in the food chain and goes all the way down to insects and even bacteria. With the wolf no longer roaming his native land; the ecosystem was out of balance.

After the wolves were reintroduced to Yellowstone

When the wolf was reintroduced to Yellowstone in 1995, elk and other grazing animals changed their behavior. Instead of staying in one area and overgrazing it, they returned to a more natural and cautious behavior which meant the elk had to stay on the move to avoid the wolf. Wolves prey on the weak and sick animals in a herd which helps keep the herd healthy.

Before wolves were returned to Yellowstone, coyotes were taking advantage of their mid level predator status. Opportunistic coyotes prey on the young and pronghorn populations were in decline. It was only after the reintroduction of wolves that the pronghorn began a slow comeback and the coyote population declined by 50%.

The over inflated populations of elk and moose declined to more sustainable numbers the land could support after the reintroduction of the wolf. With grazing animals on the move, wetlands, meadows and Aspen groves have been able to return to a healthy state and wildlife that depend on these habitats to survive have been returning.

Wolf critics claim countries like Japan, Scotland and the United Kingdom are doing fine with no wolves on their soil. However, it's not true. All three countries are considering plans to reintroduce the wolf and other keystone species to the lands they once occupied.

If the wolf is eliminated from Yellowstone, trees, plants and wildlife will begin another downward spiral to unhealthy ecosystems. With the wolf soon to be removed from the Endangered Species list, all of the forward movement of healing that has taken place in the Yellowstone area will be at risk. It's important to make sure this keystone species continues to have a presence in Yellowstone to maintain a proper balance of nature.

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