title: Predation risk affects reproductive physiology and demography of elk.
abstract: Elk (Cervus elaphus) in the Greater Yellowstone Ecosystem alter patterns of aggregation, habitat selection, vigilance, and foraging in the presence of wolves (Canis lupus). Antipredator behaviors like these can reduce predation risk but are also likely to carry costs. Data from five elk populations studied for 16 site years showed that progesterone concentrations (from 1489 fecal samples) declined with the ratio of elk to wolves. In turn, progesterone concentrations were a good predictor of calf recruitment in the subsequent year. Together, these data suggest that wolves indirectly affect the reproductive physiology and the demography of elk through the costs of antipredator behavior.
authors.affiliation: Department of Ecology, Montana State University, 310 Lewis Hall, Bozeman, MT 59717, USA. screel@montana.edu
authors.forename: Scott
authors.initials: S
authors.lastname: Creel
authors.forename: David
authors.initials: D
authors.lastname: Christianson
authors.forename: Stewart
authors.initials: S
authors.lastname: Liley
authors.forename: John A
authors.initials: JA
authors.lastname: Winnie
mesh_terms: D000818:Animals; D003670:Deer / Q000502:physiology*; D017753:Ecosystem; D004797:Enzyme-Linked Immunosorbent Assay; D005243:Feces; D005260:Female; D008297:Male; D011157:Population Dynamics; D011235:Predatory Behavior; D011374:Progesterone / Q000378:metabolism; D012098:Reproduction / Q000502:physiology*; D019596:Wolves
chemical_list: D011374:Progesterone