Title: Vegetation Responses to Supplemental Winter Feeding of Elk Authors
|Dean, Ron -|
|Vavra, Marty -|
|Parks, Catherine -|
Submitted to: Western North American Naturalist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 21, 2011
Publication Date: January 15, 2012
Citation: Rinella, M.J., Dean, R., Vavra, M., Parks, C.G. 2012. Vegetation Responses to Supplemental Winter Feeding of Elk. Western North American Naturalist 72(1):78-83. Interpretive Summary: Our study quantified effects of winter elk feeding on vegetation occurring at a feedground in western Wyoming. Constriction of elk foraging habitats can result in an overuse of vegetation and if prolonged, can promote nonnative plant invasions and other undesirable changes in plant communities as well as decreased elk carrying capacity. In this study, a feedground was established and a series of photos and vegetative cover measurements were taken prior to elk feeding and again 25 years later. The largest vegetation change in our study was the disappearance of shrubs and the increase in nonnative grasses on the feedground, but these changes did not extend outside the feedground. We concluded that change in vegetation in the feedground area was limited and feeding elk on the feedground did not impact vegetation of the extended landscape.
Technical Abstract: Some western states have resorted to supplemental winter feeding programs for elk to compensate for reductions in habitat. Our study quantified effects of winter elk feeding on native and nonnative vegetation occurring at a feedground in western Wyoming. A feedground was established in the upper Greys River to reduce winter starvation during the winter of 1981-82. A series of photo points and vegetative transects were established on the site prior to elk feeding to document effects on vegetation structure and composition. Photo points were retaken and vegetative transects reread in 2006. Along each 30.5 m transect 10 plots (.3 m x .6 m ) were established at 3 m intervals and used to estimate cover of grass, forb, shrub, litter, bare soil, and rock. Shrub canopy cover was determined by measuring the line intercept in centimeters for each shrub species along the 30.5 m transects. The cover data were not well-approximated by normal distributions because they were restricted to the 0-100% interval and contained many zeros. We used non-parametric statistics (i.e. bootstrap confidence intervals) to estimate change in cover between 1981 and 2006. The largest vegetation change in our study was the disappearance of shrubs and the increase in nonnative grasses on the feedground. These effects of elk feeding did not extend outside the feedground. Far removed from the feedground, changes in cover variables were small and inconsistent.