Wolves Are a Critical Keystone Species In a Healthy Ecosystem
Wolves: A Critical Keystone Species
An ecosystem is a biological community of interacting organisms and their physical environment. It includes all of the living things interacting with each other and non-living environments (weather, earth, sun, soil, climate, atmosphere) in a given area.
In an ecosystem, all species rely on each other and each organism has its’ own niche or role to play. A keystone species is a plant or animal that plays a disproportionately large role in the ecosystem – impacting both the prevalence and population levels of other species within their community. A keystone species is often, but not always, a predator. Outnumbered greatly by their prey, predators can control the distribution and population of large numbers of prey species.
Wolves are a critical keystone species in a healthy ecosystem. By regulating prey populations, wolves enable many other species of plants and animals to flourish. In this regard, wolves initiate a domino effect – “touching” songbirds, beaver, fish, and butterflies. Without predators, such as wolves, the system fails to support a natural level of biodiversity.
“I now suspect that just as a deer herd lives in mortal fear of its wolves, so does a mountain live in mortal fear of its deer. And perhaps with better cause, for while a buck pulled down by wolves can be replaced in two or three years, a range pulled down by too many deer may fail of replacement in as many decades.” ~Aldo Leopold, A Sand County Almanac
Yellowstone: A Wild Homecoming
The recovery of the gray wolf after its eradication from Yellowstone National Park, nearly a century ago, serves as a demonstration of how critical keystone species are to the long-term sustainability of the ecosystems they inhabit. In the 70-year absence of wolves in the Park, elk had become accustomed to grazing tender, native willows along stream banks without much predation risk. The consequences of an elk population without a top predator included a decline of the deciduous trees elk eat, a decline of beavers due to the decline of willow and aspen, and a decline in songbirds. These consequences indicate that changes in the wolf population have trickle-down effects on other populations, a phenomenon known as a “trophic cascade”.
With the support of the American public two decades ago, the federal government gave the green light to return wolves to portions of their native range in the West in 1995 and 1996 – including Yellowstone. The wildlife conservation event opened a new chapter in Yellowstone’s history, with a homecoming that changed the Park.
Wolves: Nature’s Miracle Workers?
Wolves are wildlife managers, but not miracle workers, alas…