IMPACTS OF INCREASED WINTER SNOW COVER ON UPLAND TUNDRA VEGETATION - A CASE EXAMPLE

The erection of a snow fence on upland tundra caused a significant change of the vegetation over 11 yr. Compared to nearby exposed tundra, the presence of the snow fence resulted in a warmer soil in winter and a moister and cooler soil in summer. Moisture-intolerant species such as Cetraria nivalis and C. cuculata disappeared completely or decreased in frequency, whereas the more moisture-tolerant species such as Vaccinium uliginosum and Arctostaphylos alpina increased in frequency or established at the site. In terms of climate, any change that promotes a greater winter snowfall, which is the case for warming scenarios in general circulation models, would initiate a relatively rapid change in species composition on upland tundra, particularly if accompanied by increased summer rainfall.