The Importance of Keystone Species

Posted by Dawn M. Smith Aug 9, 2007

When wolves were reintroduced to Yellowstone National Park, plenty of change followed. Coyote populations dropped while fox numbers increased. Elk and deer numbers went down while aspen stands recovered. When white-tailed prairie dog towns were wiped out, the black-footed ferrets went with them. When disease hit rabbits in Spain and Portugal, the Iberian lynx was pushed to the brink of extinction. In the Pacific Ocean the sea otter's presence allows kelp beds to thrive.

What is a Keystone Species?

In each case the species removed or added was a keystone species. The keystone in architecture is the stone in the top of the arch that locks the rest of the stones in place. In the cases of the wolf and the sea otter it is clear that they are keystone species which keep the ecosystem in balance. The wolf functions as the top predator and the sea otter's consumption of shellfish protects the kelp beds.

Prey as Keystone Species

In the other two situations the keystone species are the prey. In the example of the prairie dog, biologists were not aware of how vital a role they played in their habitat. They knew that the prairie dog was a food source but not how much the ecosystem depended on them.In addition to the ferrets utilizing their burrows, plovers and burrowing owls take advantage of them for nest sites. The burrows also drain rainwater, preventing erosion.

The same was true in the case of the Iberian lynx. The rabbit was a keystone species, necessary for the survival of the lynx both as a food source and for their effect on the habitat. The rabbits’ browsing and burrowing behaviors kept the areas from becoming wooded. The lynx prefers grass and shrub lands. The removal of rabbits and prairie dogs in their respective habitats caused problems for many species sharing the habitat.

In architecture keystones come in many shapes, sizes and styles. In nature, keystone species are equally varied.