• Login
    View Item 
    •   Home
    • University of Alaska Fairbanks
    • UAF Graduate School
    • Biological Sciences
    • View Item
    •   Home
    • University of Alaska Fairbanks
    • UAF Graduate School
    • Biological Sciences
    • 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

    Stopover ecology of semipalmated sandpipers (Calidris pusilla) at coastal deltas of the Beaufort Sea, Alaska

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    Churchwell_uaf_0006E_10453.pdf
    Size:
    8.221Mb
    Format:
    PDF
    Download
    Author
    Churchwell, Roy Thomas
    Chair
    Powell, Abby
    Committee
    Gens, Rudiger
    Dunton, Kenneth
    Blanchard, Arny
    Hundertmark, Kris
    Hollmen, Tuula
    Metadata
    Show full item record
    URI
    http://hdl.handle.net/11122/6366
    Abstract
    Avian migration is one of the wonders of the natural world. Stored fats are the main source of nutrients and fuel for avian migration and it is assumed the fat deposition at stopover sites is a critical component of a successful migration. Stopover sites are crucial in the successful migration of many birds, but particularly for arctic-breeding shorebirds that migrate long distances from breeding to wintering grounds. Despite the importance of stopover sites, it is often difficult to determine the importance of these sites to migrating shorebirds. I investigated three aspects of stopover ecology of Semipalmated Sandpipers (Calidris pusilla) foraging at coastal deltas on the Beaufort Sea coast, Alaska. First, I quantified the spatial and temporal distribution and abundance of the benthic macroinvertebrate community living within the mudflats. I found that there were two ecological groups of macroinvertebrates using river deltas, one originated in terrestrial freshwater habitats and most importantly could withstand freezing in delta sediments over the winter, and the other originated from the marine environment, could not withstand freezing and had to migrate to intertidal habitats each summer from deeper water areas that did not freeze over the winter. Stable isotope analysis allowed me to describe the origin of carbon consumed by invertebrates in intertidal habitats. I predicted freshwater invertebrates would consume terrestrial carbon, and marine invertebrates would consume marine carbon, but I found that both groups utilized the same carbon, which was a mixture of terrestrial and marine sources. My second research question determined the importance of delta foraging habitat for fall migrating Semipalmated Sandpipers. I mapped the temporal distribution and abundance of birds and quantified this relationship to invertebrate distribution and abundance. I researched fattening rates of shorebirds by measuring triglycerides in the blood of shorebirds I captured. I hypothesized that triglyceride levels would be correlated with invertebrate abundance and related to habitat quality; however, I found no relationship. Next, I determined shorebird dependence on marine invertebrates using the stable isotope signature of invertebrates and shorebird plasma. I found that shorebird abundance was associated with invertebrate abundance, and that shorebirds did feed almost exclusively on invertebrates from the mudflats later in the season. I did not find a significant difference in habitat quality among the deltas, although more birds were counted at the Jago Delta than at the other two deltas. Finally, I researched the question of how change in water levels due to lunar tides and storm surge events impacted the availability of foraging habitat. I assessed the phenology of Semipalmated Sandpiper migration and how this related to the availability of forage based on abundance, distribution, and accessibility of macroinvertebrates. There was a significant decline in the calories available for forage when there was a lunar tide and when there was a storm surge event. The most foraging habitat was available late in the migration period, while the peak in Semipalmated Sandpiper migration was early in the period. Late in the season there is also a greater chance of a storm surge event occurring due to the lack of sea ice during that period. In summary, I found Beaufort Sea deltas were more diverse than I expected both in macroinvertebrate community and in how shorebirds use the available foraging habitat. After completing this research I feel this habitat is critical to Semipalmated Sandpiper migration; however, there is a real risk of extensive change to these deltas due to future warming with negative consequences for shorebirds.
    Description
    Dissertation (Ph.D.) University of Alaska Fairbanks, 2015
    Date
    2015-12
    Type
    Dissertation
    Collections
    Biological Sciences
    Theses supervised by AKCFWRU

    entitlement

     
    ABOUT US|HELP|BROWSE|ADVANCED SEARCH

    The University of Alaska Fairbanks is an affirmative action/equal opportunity employer and educational institution and is a part of the University of Alaska system.

    ©UAF 2013 - 2023 | Questions? ua-scholarworks@alaska.edu | Last modified: September 25, 2019

    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.