Yellowstone wolf numbers down, elk up
by Cat Urbigkit, Pinedale Online!
March 7, 2009
While we're waiting for the U.S. Fish and Wildlife Service to issue its annual report on wolves in the Northern Rockies, here's a Yellowstone National Park press release about wolf numbers declining in the park. It was issued in January. Scroll down to learn that elk numbers on the Northern Range are up.
"The number of wolves in Yellowstone National Park declined last year. It’s the first drop in wolf numbers in the park in three years.
The Yellowstone Wolf Project reports the 2008 population at 124 wolves, down 27 percent from the 171 wolves recorded in 2007.
The greatest decline occurred on the northern range, the area with the greatest wolf population density. The wolf population there dropped 40 percent, from 94 to 56 wolves.
The decline in the wolf population in the interior of the park was smaller. That population dipped from 77 to 68 animals, off 11 percent from the previous year.
A similar population decline most recently occurred between 2004 and 2005, when overall wolf numbers in Yellowstone dropped from 171 to 118 animals.
The number of breeding pairs in the park also declined from 10 to 6. This is the lowest number of breeding pairs recorded since 2000 when wolves first met the minimum population requirement for delisting.
2008-09 WINTER COUNT OF NORTHERN YELLOWSTONE ELK:
The Northern Yellowstone Cooperative Wildlife Working Group conducted its annual winter survey of the northern Yellowstone elk population on January 30 and February 9, 2009. A total of 7,109 elk were counted from airplanes during good survey conditions. Approximately one-half of the observed elk were located within Yellowstone National Park, and one-half were located north of the park boundary. The northern Yellowstone elk herd winters between the northeast entrance of Yellowstone National Park and Dome Mountain/Dailey Lake in the Paradise Valley.
This year’s count was slightly higher than the counts during the three previous winters (6,279 -6,738 elk), but lower than the 9,545 elk counted in winter 2005. The slight increase in elk counted during winter 2009 compared to the three previous winters "may reflect favorable counting conditions, a reduction in the hunter harvest of antler-less elk, and a reduction in wolf predation owing to a fairly large decrease in wolf numbers during the summer of 2008" according to P.J. White, biologist for Yellowstone National Park. Wolf numbers on the portion of the northern range inside the park decreased by 40%, from 94 to 56 wolves, during 2008.
The long-term trend in counts of northern Yellowstone elk indicates abundance has decreased significantly (60%) since wolf restoration. Predation by wolves and other large carnivores, human harvests of antler-less elk during the Gardiner Late Hunt and drought effects on maternal condition and recruitment were indicated as the primary factors contributing to this decreasing trend during 1995-2005. However, the Montana Department of Fish, Wildlife, and Parks decreased the number of antler-less elk permits from 1,102 in 2005 to 100 per season during 2006-2009 owing to decreases in elk abundance and recruitment. This adjustment of permits was intended to increase the number of prime-aged females in the population which, in turn, should increase the recruitment rates of calves into the breeding population.
Collaborative analyses by the Montana Department of Fish, Wildlife, and Parks, Montana State University, and the National Park Service suggest elk numbers have decreased in areas where combined high numbers of wolves and grizzly bears occurred in relation to numbers of elk, while elk populations remained stable or increased where consistently low numbers of wolves and/or grizzly bears coexisted with elk and moderate levels of hunter harvest occurred. Also, elk calf recruitment is generally lower in areas where the ratio of predators to prey is higher. Thus, White added "I’d expect numbers of elk on the northern range to remain similar to this year’s count or decrease somewhat further in coming years if predator to prey ratios remain relatively high—even if human harvests remain low." Tom Lemke, biologist for Montana Fish, Wildlife and Parks, also cautioned that, "Even though biologists counted 830 more elk than last year, it is unlikely we will see any significant long-term increase in elk numbers until there is long-term improvement in elk calf recruitment rates." Last year’s recruitment rate was 11 calves per 100 cows. Elk recruitment objectives for this population are 20-30 calves per 100 cows. Although other factors can be and are considered, the poor recruitment rates over the last number of years are largely attributable to high predation rates. This year’s calf recruitment rate will be estimated during helicopter surveys conducted in March.
Montana’s State Elk Management Plan calls for a wintering population objective of 3,000-5,000 elk north of Yellowstone National Park, with 2,000-3,000 of those animals wintering on or near the state-owned Dome Mountain Wildlife Management Area. "This year biologists counted 3,511 elk north of the park with 2,896 of those elk wintering in the Dome Mountain area," according to Lemke. "In fact, elk survey numbers have been within population objectives for about the last seven years", Lemke added. In contrast, during the last five years of the 1990’s, 5,300-8,600 elk wintered north of the park with 3,500-4,500 elk in the Dome Mountain area. Wintering such large numbers of elk could lead to long-term habitat decline and increase the likelihood of game damage on private lands.
The Working Group will continue to monitor trends of the northern Yellowstone elk population and evaluate the relative contribution of various components of mortality, including predation, environmental factors, and hunting. The Working Group was formed in 1974 to cooperatively preserve and protect the long-term integrity of the northern Yellowstone winter range for wildlife species by increasing our scientific knowledge of the species and their habitats, promoting prudent land management activities, and encouraging an interagency approach to answering questions and solving problems. The Working Group is comprised of resource managers and biologists from the Montana Fish, Wildlife, & Parks, National Park Service (Yellowstone National Park), U.S. Forest Service (Gallatin National Forest), and U.S. Geological Survey-Northern Rocky Mountain Science Center, Bozeman.