Skip to Main Content
U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Home > Search > Publication Information

  1. Share via EmailShare on FacebookShare on LinkedInShare on Twitter
    Dislike this pubLike this pub
    Author(s): Svetlana Yegorova
    Date: 2013
    Source: Gen. Tech. Rep. PNW-GTR-880. Portland, OR: US Department of Agriculture, Forest Service, Pacific Northwest Research Station: 118-118.
    Publication Series: General Technical Report (GTR)
    Station: Pacific Northwest Research Station
    PDF: View PDF  (74.45 KB)

    Description

    Forest thinning has been widely used in the Pacifi c Northwest as a technique to accelerate latesuccessional vegetation characteristics and promote mature forest habitats for wildlife. Th inning treatments aff ect tree and understory vegetation development. Th e eff ects of thinning on bird abundance and occurrence vary by bird species and change over time, presumably as a result of changes in understory and overstory vegetation after thinning. However, this assumption has rarely been tested. Vegetation characteristics, such as canopy cover, understory density and composition are frequently used in habitat modeling because they are likely to constitute both proximate cues to habitat selection and ultimate resources that contribute to fi tness. However, a disturbance event, such as forest thinning, may decouple habitat selection cues from fi tness variables. Th is study investigates the potential of such decoupling for eight bird species by examining dynamics in bird occurrence or abundance in relation to changes in vegetation characteristics within Douglas-fi r (Pseudotsuga menziesii) stands over 10 years since thinning. Our objectives are to: 1) determine if specifi c vegetation characteristics account for bird species occurrence or abundance in thinned and unthinned forests; and 2) explore whether the relationships between vegetation characteristics and bird occurrence changes over time. We conducted bird surveys at 58 point-count stations during six breeding seasons in a 10-year period following forest thinning. We obtained detailed local- and landscape-level vegetation characteristics for all bird sampling points. We accounted for imperfect detection and modeled occurrence or abundance of eight avian species as a function of local and landscape-scale vegetation characteristics with generalized linear mixed models. Preliminary results suggest that for some species vegetation is a good predictor of occurrence and that relationship to vegetation remains consistent over 10 years. However, for other species these relationships vary.

    Bird-vegetation relationships appear to be highly dynamic, even in a system characterized by relatively low-impact disturbance. We hypothesize that this variability is best explained by intrinsic population processes rather than plasticity in avian habitat selection.

    Publication Notes

    • You may send email to pnw_pnwpubs@fs.fed.us to request a hard copy of this publication.
    • (Please specify exactly which publication you are requesting and your mailing address.)
    • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
    • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.

    Citation

    Yegorova, Svetlana. 2013. Effects of forest thinning on bird-vegetation relationships in young Douglas-fir forests. In: Anderson, P.D.; Ronnenberg, K.L., eds. Density management in the 21st century: west side story. Gen. Tech. Rep. PNW-GTR-880. Portland, OR: US Department of Agriculture, Forest Service, Pacific Northwest Research Station: 118-118.

    Keywords

    thinning, understory vegetation, overstory structure and composition, birds, habitat selection

    Related Search


    XML: View XML
Show More
Show Fewer
Jump to Top of Page