FLORISTICAL AND ECOLOGICAL CHARACTERIZATION OF THE POLAR DESERT ZONE OF GREENLAND

Species composition and biomass of four plant communities were investi gated in two coastal polar desert areas in eastern North Greenland, bo rdering the North East Water Polynya - an ice-free sea area kept open by upwelling - and compared with inland areas in North Greenland. Herb barren, the poorest type, has a species richness of 6 species/m(2), a cover of 0.7 %, and an above-ground biomass of 0.6 g/m(2) (vascular p lants). The richest type, Saxifraga oppositifolia snowbed, has 10 spec ies/m(2), 5.0 % cover, and 11.2 g/m(2) biomass. A floristic and Vegeta tion boundary exists a few kilometres from the coast. The coastal area s bordering the North East Water Polynya had an impoverished flora and Vegetation compared to areas near the ice-covered sea, possibly cause d by very low summer temperatures and high frequency of clouds. A new delimitation of the polar deserts of Greenland is proposed on the basi s of the number of vascular plant species, the occurrence of species w ith a specific inland distribution in North Greenland and the dominati ng life forms. At present the polar desert zone includes only areas wi thin a zone up to ca. 15 km from the outer coast of high arctic Greenl and - north of ca. 80 degrees N. Large areas formerly classified as po lar deserts in eastern North Greenland, as well as in Washington Land in western North Greenland, are excluded. New floristic data confirm t hat Greenland is correctly included in the Canadian province of the ar ctic polar deserts, whereas there is no reason for subdividing the pol ar deserts of the Canadian province.