MONITORING AND ASSESSMENT OF WOLF-UNGULATE INTERACTIONS AND TRENDS WITHIN THE GREATER YELLOWSTONE ECOSYSTEM
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Ken Hamlin
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RESEARCH COMPONENTS
Wolf-Ungulate Dynamics in Upper Gallatin Canyon
John Winnie and Scott Creel
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Our project centers around 4 questions: 1) What is the effect of wolf predation (offtake) on local elk populations? 2) At the scale of landscapes, do elk shift their use of habitat in response to the threat of predation? 3) At the scale of the herd and individual, do elk alter their behavior in response to the threat of predation? 4) If elk do respond behaviorally to predation pressure, do these responses carry nutritional or stress costs? If the answer to question 4 is yes, and these costs are sufficiently large, then this research may lead to fundamental changes in the modeling of predator-prey systems.
To address these questions, we are monitoring the following variables on 4 study sites in the upper Gallatin drainage. Elk: behavior; nutritional status and stress hormone levels (measured noninvasively through urine and fecal samples respectively); distribution across the landscape; herd size, composition (see figure), and geometry; as well as wolf presence, numbers and offtake (see figure). We are also gathering fine-scaled data on weather and snow pack, and recording the presence of humans, to control for the influences of these variables on elk. |
A pair of wolves in the Taylor Fork drainage. © John Winnie, Jr.
Daly Creek drainage along the upper Gallatin river. © John Winnie, Jr. |
The
Chief Joseph pack roams from Big Sky south to just north of West Yellowstone,
and from the Taylor Fork drainage in the west, to the Tom Miner Basin in the
east. Last year (2001), the pack frequently traveled even farther west, to the
Madison Valley.
In early 2001, Chief Joseph numbered 12 wolves. Then, in mid-summer, the alpha female was killed by a car on Hwy. 191 and 2 months later, the alpha male was killed by a bull elk. The remaining pack members raised the year’s pups, until sometime in December when the pack fragmented and four of the adults headed west to the Madison drainage (one these subsequently moved north to Wolf Creek, north of Helena, and was shot while preying on sheep). Chief Joseph currently numbers 6 or 7 wolves, and is denning in the study area. The Park Service will attempt to get a pup count sometime mid-summer.
In addition to Chief Joseph, two other wolf pairs may have denned in the study area, although this is difficult to confirm since none of these wolves are wearing radio collars. With some luck, we will soon know more about these animals, as the U.S. Fish and Wildlife service will be attempting to collar them this summer and fall.
In February on 2002, Montana Fish Wildlife and Parks, in cooperation with MSU researchers, radio-collared 38 elk along the upper Gallatin river. Eight of the collars were equipped with GPS units which will record the elks’ location every 2 hours. These collars are also equipped with automatic drop-off mechanisms which are set to release in January of 2003. Using the data from the elk radio and GPS collars, in combination with data from wolf radio collars, we hope to determine if wolves cause elk to change their use of habitat.
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MSU graduate student John Winnie, Jr. radio-tracking wolves in the Taylor Fork drainage. |
Ken Hamlin and Mike Ross of Montana Fish Wildlife and Parks prepare to board the incoming helicopter during the February 2002 elk collaring operation. |
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Dr. Scott Creel of MSU (L), and Ken Hamlin of Montana Fish Wildlife and Parks, heading out to radio collar elk on the upper Gallatin. |
Mike Ross (L) takes a blood sample, while Ken Hamlin estimates a cow elk’s age from tooth wear. |
All photos © John Winnie, Jr.
Funding: National Science Foundation and Montana Fish, Wildlife and Parks
