• Login
    View Item 
    •   Home
    • University of Alaska Fairbanks
    • UAF Graduate School
    • Older Theses Not Clearly Affiliated with a Current College
    • View Item
    •   Home
    • University of Alaska Fairbanks
    • UAF Graduate School
    • Older Theses Not Clearly Affiliated with a Current College
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of Scholarworks@UACommunitiesPublication DateAuthorsTitlesSubjectsTypeThis CollectionPublication DateAuthorsTitlesSubjectsType

    My Account

    Login

    First Time Submitters, Register Here

    Register

    Statistics

    Display statistics

    Foraging ecology of female Dall's sheep in the Brooks Range, Alaska

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    Hansen_M_1996.pdf
    Size:
    4.299Mb
    Format:
    PDF
    Download
    Author
    Hansen, Michael Charles
    Keyword
    Forestry
    Ecology
    Metadata
    Show full item record
    URI
    http://hdl.handle.net/11122/9427
    Abstract
    Most wild sheep (Ovis) are primarily diurnal. Thus, extreme cold, darkness, and limited quantities of low-quality forage during long winters above the Arctic Circle present a formidable challenge for sheep. Further, summer is particularly short at these high latitudes, providing little time for sheep to accumulate energy reserves for winter. This thesis discusses dietary and behavioral responses of wild sheep to the constraints of Arctic environments. Specifically, I determined diet composition and selection, forage quality, nutrient intake, and activity budgets of adult female Dall's sheep (ewes) (Ovis dalli dalli) near the northern extreme of the range of wild sheep for 2 years and constructed a model of the energy relationships of these animals. Ewes primarily consumed forbs and grasses during summer, and strongly selected forbs over other forages in accordance with the predictions of optimal foraging theory. Diets primarily consisted of grasses in early winter, shifted to sedges in February, and back to grasses in early spring. Shrubs were consistently the least selected class of forage. When the diet was composed of forages with varying digestibility, microhistological analyses not corrected for differential digestibility were biased toward less digestible forage. Winter forage available to Dall's sheep in the northern Brooks Range was low in both digestibility and protein content. In early summer ewes foraged during all hours of the day when sunlight was present for 24 hours. Sheep restricted their foraging almost entirely to daylight hours near the equinoxes, and foraged during all available hours of light, as well as 2.8 hours of the night in December. Daily foraging time varied from 12.9 hours in June to 7.9 hours in December, and, when measured on a daily basis, was positively correlated with average windchill and daylength. Ash-free fecal nitrogen and in vitro digestible dry matter were most highly correlated with activity level on a monthly basis. Energetics modeling indicated that ewes were in a negative energy balance for 6-8 months each winter and lost nearly 30% of their body weight. Duration of the short summer growing period was most important for weight gain, and presence of deep snow determined weight loss in winter.
    Description
    Dissertation (Ph.D.) University of Alaska Fairbanks, 1996
    Date
    1996
    Type
    Dissertation
    Collections
    Theses supervised by AKCFWRU
    Biological Sciences
    Older Theses Not Clearly Affiliated with a Current College
    Theses (Unassigned)

    entitlement

     
    ABOUT US|HELP|BROWSE|ADVANCED SEARCH

    The University of Alaska is an affirmative action/equal opportunity employer, educational institution and provider and prohibits illegal discrimination against any individual.

    Learn more about UA’s notice of nondiscrimination.

    Open Repository is a service operated by 
    Atmire NV
     

    Export search results

    The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

    By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.

    To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

    After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.