Do stable isotopes reflect dietary niche?
Kelley M. STEWART & R. Terry BOWYER, Institute of Arctic Biology and Department of Biology and Wildlife,University of Alaska Fairbanks, Fairbanks, Alaska 99775-7000, U.S.A. John G. KIE & Brian L. DICK, United States Forest Service, Pacific Northwest Research Station, 1401 Gekeler Lane, La Grande, Oregon 97850, U.S.A. Merav BEN-DAVID, Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming 87021, U.S.A. Abstract: We examined dietary niches of mule deer (Odocoileus hemionus), North American elk (Cervus elaphus), and free-ranging cattle (Bos taurus) that frequently co-occur in western North America. We tested the hypothesis that those three species would exhibit little overlap in diet and that mule deer, the smallest in body size of the three species, would forage more selectively than either elk or cattle. We determined diet composition from microhistological analysis and used principal components analysis to assess dietary niches. In addition to those conventional
