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Doug Smith Yellowstone Wolf Project Leader, Yellowstone National Park, Wyoming Roger Anderson Julie Mao
Back to Chapter 6: Restoration Articles Restoration of mountain yellow-legged frogs in Kings Canyon By Harold Werner Breathing space at Lechuguilla Cave By Jason M. Richards National Park Service to share science role in Everglades restoration By Thomas Van Lent California condors return to the Colorado Plateau By Elaine Leslie Wetland and stream restoration at Elk Meadow in Redwood National Park By James H. Popenoe Other Developments Award-winner Profile - Botanist honored with first professional excellence award Preservation of the Fort Dupont stream Coastal dune restoration at Point Reyes Bonytail restoration continues Maintenance staff help restore native fish at Point Reyes |
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 By Douglas W. Smith, Roger J. Anderson, and Julie Mao Reintroduction of 31 gray wolves into Yellowstone National Park in 1995 and 1996, after a 60-year absence, has proved to be a remarkable success story for the National Park Service, ushering in a new ecological era for the greater Yellowstone area. Approximately 216 wolves now reside in this area, comprising 24 packs with 14 breeding pairs that produced 77 surviving puppies. Ten of the packs make their home in Yellowstone National Park. The goal of the wolf restoration program is to maintain 30 breeding pairs throughout the three Rocky Mountain recovery areas—greater Yellowstone, central Idaho, and northwest Montana. Once 30 pairs reproduce for three successive years, the gray wolf can be removed from the endangered species list in Idaho, Montana, and Wyoming. The restoration program reached several important milestones in 2001. Biologists determined that the number of breeding pairs in the recovery areas had reached 30 late in 2000, meeting the population criteria necessary for delisting the wolf for the first time. These gains were solidified in 2001 when the number of reproducing pairs increased to 35, further ensuring the population’s recovery. Wolves could be recommended for delisting as early as 2003 if the population criteria are met for the third year. Congressionally decreed public land policy had mandated predator removal, especially of wolves, and by 1926 Yellowstone’s top carnivore was gone. Missing, too, was the critical role wolves played in the ecosystem. Animals that can affect a broad array of other animal and plant species, like wolves, are called “keystone species” and often enhance the biodiversity of a natural system. Now that wolves have returned to the greater Yellowstone area, will they fulfill their role as top carnivores? So far, wolves have not impacted the elk population, although elk make up 87% of their diet. Prey populations fluctuate for many complex reasons with weather and predators being the two most important factors. A catastrophically severe winter from 1996 to 1997 lowered the elk population by several thousand; however, a series of mild winters helped the population bounce back, even with a restored wolf population. In addition to wolves, five other species, including humans, prey on elk; yet, the elk population has increased in recent years. If the elk population has not changed, have wolves had an indirect effect on elk? Fortunately, data are available on elk before wolf reintroduction. These data also precede the 1988 Yellowstone fires, another major ecological jolt to Yellowstone and a factor that complicates analysis. To date, researchers using radio collars have found little change in elk habitat use before and after wolf reintroduction. The only significant change detected was that elk have been summering at higher elevations since the wolves were reestablished. This could also be due to other factors, such as the drought conditions that have prevailed since the reintroduction effort began. Elk might venture to higher elevations in search of forage less affected by drought. It is still too early to know what the ultimate influence of wolves will be on the Yellowstone ecosystem. Other studies have revealed increases in biological diversity with carnivore restoration. Already, wolves have dramatically lowered the coyote population, which will likely influence other species. Other findings indicate that improved aspen growth occurs in areas with high wolf activity, but low elk use. Besides aspen and elk, many other plant and animal species stand to gain from the restoration of this long-absent, keystone carnivore. What is clear is that wolf restoration in Yellowstone has been successful beyond all expectations. The greatest victory of the effort to restore wolves to the greater Yellowstone area may be a philosophical one: An attempt has been made to restore all of the parts and processes of a natural ecosystem.
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This material is from Natural Resource Year in Review--2001, published by the National Park Service, U.S. Department of the Interior, in May 2001 (publication D-2255) /YearInReview/yir/yir2001/06_restoration/06_5_smith_YELL.html Last Updated: |
