title: Linking habitat selection to fitness-related traits in herbivores: the role of the energy landscape.
abstract: Animals may partially overcome environmental constraints on fitness by behaviorally adjusting their exposure to costs and supplies of energy. Few studies, however, have linked spatiotemporal variation in the energy landscape to behaviorally mediated measures of performance that ostensibly influence individual fitness. We hypothesized that strength of selection by North American elk (Cervus elaphus) for areas that reduced costs of thermoregulation and activity, and increased access to high-quality forage, would influence four energetically mediated traits related to fitness: birth mass of young, nutritional condition of adult females at the onset of winter, change in nutritional condition of females between spring and winter, and neonatal survival. We used a biophysical model to map spatiotemporally explicit costs of thermoregulation and activity experienced by elk in a heterogeneous landscape. We then combined model predictions with data on forage characteristics, animal locations, nutritional condition, and mass and survival of young to evaluate behaviorally mediated effects of the energy landscape on fitness-related traits. During spring, when high-quality forage was abundant, female elk that consistently selected low-cost areas before parturition gave birth to larger young than less-selective individuals, and birth mass had a strong, positive influence on probability of survival. As forage quality declined during autumn, however, lactating females that consistently selected the highest quality forage available accrued more fat and entered winter in better condition than less-selective individuals. Results of our study highlight the importance of understanding the dynamic nature of energy landscapes experienced by free-ranging animals.
authors.affiliation: Department of Biological Sciences, Idaho State University, Pocatello, ID, 83209, USA. ralong@uidaho.edu.|Department of Fish and Wildlife Sciences, University of Idaho, Moscow, ID, 83844, USA. ralong@uidaho.edu.
authors.forename: Ryan A
authors.initials: RA
authors.lastname: Long
authors.affiliation: Department of Biological Sciences, Idaho State University, Pocatello, ID, 83209, USA.
authors.forename: R T
authors.initials: RT
authors.lastname: Bowyer
authors.affiliation: Department of Zoology, University of Wisconsin Madison, Madison, WI, 53796, USA.
authors.forename: Warren P
authors.initials: WP
authors.lastname: Porter
authors.affiliation: Department of Zoology, University of Wisconsin Madison, Madison, WI, 53796, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Mathewson
authors.affiliation: Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology, University of Wyoming, Laramie, WY, 82071, USA.
authors.forename: Kevin L
authors.initials: KL
authors.lastname: Monteith
authors.affiliation: Oregon Department of Fish and Wildlife, La Grande, OR, 97850, USA.
authors.forename: Scott L
authors.initials: SL
authors.lastname: Findholt
authors.affiliation: US Forest Service, Pacific Northwest Research Station, La Grande, OR, 97850, USA.
authors.forename: Brian L
authors.initials: BL
authors.lastname: Dick
authors.affiliation: Department of Biological Sciences, Idaho State University, Pocatello, ID, 83209, USA.
authors.forename: John G
authors.initials: JG
authors.lastname: Kie
mesh_terms: D000818:Animals; D003670:Deer; D017753:Ecosystem; D060434:Herbivory; D006801:Humans; D007774:Lactation
keywords: Behavior; Biophysics; Energetics; Ingesta-free body fat; Thermoregulation