Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

Effect of Grazing by Greater Snow Geese on the Production of Graminoids at an Arctic Site (Bylot Island, NWT, Canada)

Gilles Gauthier, R. John Hughes, Austin Reed, Julien Beaulieu and Line Rochefort
Journal of Ecology
Vol. 83, No. 4 (Aug., 1995), pp. 653-664
DOI: 10.2307/2261633
Stable URL: http://www.jstor.org/stable/2261633
Page Count: 12
  • Read Online (Free)
  • Download ($18.00)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Effect of Grazing by Greater Snow Geese on the Production of Graminoids at an Arctic Site (Bylot Island, NWT, Canada)
Preview not available

Abstract

1 Arctic ecosystems are sensitive to grazing because of their low overall net primary production. We therefore studied the effect of greater snow geese on the production of arctic graminoids. 2 At Bylot Island, NWT ($73^\circ N$), breeding snow geese graze Eriophorum scheuchzeri and Dupontia fisheri in lowland polygon fens. Vegetation in seasonal exclosures was sampled at 2-week intervals from mid-June to mid-August 1990, 1991 and 1993 (ungrazed areas) and compared with plant growth in short-term exclosures set up over grazed areas. Standing crop (above-ground biomass), net above-ground primary production (NAPP) and nitrogen content were determined for both plant species. 3 Goose faeces were used as an index of grazing intensity. Cumulative faeces counts increased from 2.2 faeces $m^{-2}$ in 1990-9.9 faeces $m^{-2}$ in 1993. 4 Peak above-ground dry biomass of ungrazed areas averaged $33 g m^{-2}$. In all years, goose grazing significantly reduced the above-ground biomass of Eriophorum and Dupontia. Over the 3 years, we estimated that geese consumed from 65 to 113% of the cumulative NAPP of Eriophorum, and from 30 to 78% of the cumulative NAPP of Dupontia. Consumption of Dupontia, but not Eriophorum, was related to grazing intensity. 5 Cumulative NAPP of grazed areas was slightly lower than that of ungrazed areas at the end of the summer. On an individual plant basis, cumulative NAPP of Dupontia, but not of Eriophorum, was reduced by grazing. Nitrogen content of plants after grazing was higher than in ungrazed plants. 6 Although grazed plants were able to grow new foliage, goose grazing did not enhance NAPP at Bylot Island as has been reported elsewhere. This could be either because grazing occurs too late in the season when the regrowth capacity of plants is low or because nutrients released from goose faeces are absorbed by mosses and are not immediately available to graminoids.

Page Thumbnails

  • Thumbnail: Page 
653
    653
  • Thumbnail: Page 
654
    654
  • Thumbnail: Page 
655
    655
  • Thumbnail: Page 
656
    656
  • Thumbnail: Page 
657
    657
  • Thumbnail: Page 
658
    658
  • Thumbnail: Page 
659
    659
  • Thumbnail: Page 
660
    660
  • Thumbnail: Page 
661
    661
  • Thumbnail: Page 
662
    662
  • Thumbnail: Page 
663
    663
  • Thumbnail: Page 
664
    664