Effects of simulated grazing in ungrazed wet sedge tundra in the High Arctic
Elliott, T. L. and G. H. R. Henry. 2011. Taylors and Francis
Abstract
Wet sedge tundra communities in the High Arctic are valuable sources of forage for
several resident and migratory herbivores; however, the effects of grazing on these
systems have been rarely studied. We simulated grazing in two wet sedge meadows at
a site on Ellesmere Island that has not been affected by grazing. Over two summers,
we clipped plots at four different frequencies and removed litter to assess effects on
aboveground net primary production, availability of soil nitrogen, shoot concentra-
tions of carbon and nitrogen, and soil temperature and moisture regimes. Available
soil nitrate and ammonium were highest in plots with intermediate clipping
frequencies. Shoot nitrogen concentrations were also greater at intermediate clipping
frequencies in two of the four species studied. Aboveground net primary production
decreased after clipping, regardless of frequency. Litter removal resulted in slightly
increased soil moisture, but had no effect on aboveground net primary production.
Soil temperature was not affected by any of our treatments. These results suggest
that nitrogen cycling is stimulated by intermediate frequencies of simulated grazing,
but clipping decreased aboveground net primary production in ungrazed high arctic
wet sedge tundra.
