Effects of military overflights on habitat use and selection by female Dall's sheep, Yukon-Tanana uplands, Alaska

• Main Author: Wendling, Bradley R.
• Format: Thesis
• Language: English
• Published: 2008
• Subjects: Dall sheep; Aircraft; Interior Alaska; Habitat; Aeronautics; Airplanes; Military; Environment; Yukon; Fairbanks; Alaska
• Online Access: http://hdl.handle.net/11122/14816

Thesis (M.S.) University of Alaska Fairbanks, 2008 "My objective was to assess the potential effects of military overflights on home range size, movement rates, habitat use, and habitat selection of female Dall's sheep (Ovis dalli) during 2-week sequential periods, April-July, 1999-2002. I examined sheep in 2 study areas overlain with designated military training airspace within the Yukon-Tanana uplands, Alaska. I examined the effects of study area, year, and sequential time period on: 1) mean home range size, 2) mean minimum hourly distance traveled by sheep, and 3) mean use and selection ratios for the habitat variables of elevation, slope, terrain ruggedness, aspect, and landcover class. Mean number of daily military sorties within sequential periods was used as a covariate in all analyses. I assessed habitat selection at 3 successive spatial scales defined as: 1) the regional geographical range of female Dall's sheep in the Yukon-Tanana uplands, 2) study areas (defined as the distribution of sheep within a localized area), and 3) selection within individual 2-week home ranges. Sheep home range size, movement rates, habitat use and selection ratios at the scale of region and study area differed between study areas, among years within study areas, and among sequential time periods within years within study areas, but did not vary in relation to military overflight intensity. I detected an effect of sorties on selection ratios at the home range scale; however, sorties explained <4% of the residual variation in these variables. I conclude that increases in intensity of military training operations during Major Flying Exercises (MFE's) over the Yukon-Tanana uplands were a relatively insignificant source of variance in activity and habitat use compared to the effects of seasons, years, and study areas"--Leaf iii National Park Service, the United States Air Force, and the Alaska Cooperative Fish and Wildlife Research Unit