Primary Production in Arctic Cottongrass Tussock Tundra Communities

Wein, Ross; Bliss, L

Four cottongrass tundra communities in Alaska and the Yukon Territory were investigated to determine phytomass components and primary production rates. The cottongrass (Eriophorum vaginatum ssp. spissum) community produces much of its new growth early in the summer, largely because of the early growth of cottongrass. Yearly primary production was estimated to be between 35 and 96 g m2 for aboveground vascular plants, between 1 and 5 g m-2 for lichens, and between 28 and 116 g m-2 for mosses. Total phytomass for two intensively studied sites was remarkably similar (7,401 and 7,567) g m-2, even though the vascular plant, lichen, and moss components varied widely. Aboveground turnover rates for filter paper, woody material, and herbaceous material were 46 to 87, 7.5 to 8.0, and 3.6 to 5.2 years, respectively, when measured by the litterbag technique. This agreed well with the 7-year turnover rate for all plant material estimated from aboveground phytomass:production ratios. Belowground turnover rates calculated from phytomass and production measurements varied from 45 to 80 years for cottongrass components and to 150 years for moss at one of the sites. Following disturbance in the cottongrass tussock community, the active layer thickens and nutrients become more available. Cottongrass, in particular, responds by accumulating more nutrients, and increasing vegetative and reproductive growth.

Primary Production in Arctic Cottongrass Tussock Tundra Communities

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