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): Lem G. Butler; Knut Kielland
    Date: 2008
    Source: Journal of Ecology. 96: 136-144
    Publication Series: Scientific Journal (JRNL)
    PDF: Download Publication  (2.2 MB)


    1. We examined the effects of browsing by moose and snowshoe hares on vegetation structure, species composition, plant demography and element cycling in 25 riparian (willow) vegetation stands along the Tanana River, interior Alaska, across a 250-km gradient that represented a fivefold range in moose densities (0.2 to 1.0 km-2). 2. Browsing frequency was much greater in areas with high moose densities. The combined browsing pressure (percentage of annual browse production consumed by herbivores) of moose (Alces alces) and snowshoe hares (Lepus americanus) on forage species was over fivefold greater in the high moose density areas (33 percent) than the low moose density areas (6 percent), reflecting the fivefold difference in moose densities. 3. Aboveground biomass of preferred willow species was lower in high moose density areas, and the age structure of the vegetation was significantly skewed toward younger age classes. This shift in age structure was accompanied by higher proportion of dead to live ramets, indicating higher mortality under increased browsing pressure. Increasing browsing pressure favoured later successional species (Alnus tenuifolia and Populus balsamifera) on the landscape, as shown by both a reduction in the number and size of willow stands in high-density areas. 4. High rates of fecal input resulted in a doubling of aboveground nitrogen input in high moose density areas. The rates of carbon and nitrogen input from willow communities to the soil as mediated by moose herbivory were approximately fivefold and eightfold greater in high moose density areas than in low moose density areas, respectively. 5. Synthesis. The effects of herbivory were manifested at several ecological hierarchies, including the individual, the community, and the landscape. Across these spatial scales, herbivory appears to accelerate the ecosystem turnover of carbon and nitrogen by a combination of both plant- and animal-based processes.

    Publication Notes

    • Visit PNW's Publication Request Page to request a hard copy of this publication.
    • 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.


    Butler, Lem G.; Kielland, Knut. 2008. Acceleration of vegetation turnover and element cycling by mammalian herbivory in riparian ecosystems. Journal of Ecology, Vol. 96, p. 136-144


    Alaska, boreal forest, herbivory, moose, riparian communities, succession

    Related Search

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