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): J. R. Webster; Jennifer Knoepp; Wayne Swank; Chelcy Miniat
    Date: 2016
    Source: Ecosystems
    Publication Series: Scientific Journal (JRNL)
    Station: Southern Research Station
    PDF: Download Publication  (989.0 KB)


    In this study, we document a functional regime shift in stream inorganic nitrogen (N) processing indicated by a major change in N export from a forested watershed. Evidence from 36 years of data following experimental clearcut logging at Coweeta Hydrologic Laboratory, NC, suggests that forest disturbance in this area can cause elevation of dissolved inorganic N (DIN) loss lasting decades or perhaps longer. This elevation of N export was apparently caused by an initial pulse of organic matter input, reduced vegetation uptake, increased mineralization of soil organic N, and N fixation by black locust-associated bacteria following clearcut logging. In forested reference watersheds at Coweeta, maximum DIN concentration occurs in summer when base flow is low, but the clearcut watershed shifted to a pattern of maximum winter DIN concentration. The seasonal pattern of DIN concentration and export from reference watersheds can be explained by terrestrial and in-stream processes, but following clearcutting, elevated DIN availability saturated both terrestrial and in-stream uptake, and the N export regime became dominated by hydrologic transport. We suggest that the long-term elevation of stream DIN concentration and export along with the changes in seasonality of DIN export and the relationship between concentration and discharge represent a functional regime shift initiated by forest disturbance.

    Publication Notes

    • You may send email to 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.


    Webster, J. R.; Knoepp, J. D.; Swank, W. T.; Miniat, C. F. 2016. Evidence for a regime shift in nitrogen export from a forested watershed. Ecosystems 19: 881-895. 15 p.  10.1007/s10021-016-9974-1


    Google Scholar


    Watershed, nitrogen, budget, regime shift, cleacutting stream

    Related Search

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