Altitudinal zonation of vegetation in continental West Greenland with special reference to snowbeds

This paper gives a brief introduction to the AZV (Altitudinal Zonation of Vegetation) project carried out in the inland of West Greenland. The aim of this project is to provide a model of altitudinal vegetation belts in subzone E (Arctic Shrub Zone) of the Circumpolar Arctic Vegetation Map (CAVM). Furthermore, the elevation zonation concept used in this map, which assumes that latitudinal bioclimatic subzones are reflected in altitudinal vegetation belts (CAVM TEAm 2003), will be tested. The model of altitudinal vegetation belts is based on 500 vegetation releves, three vegetation maps, and environmental data from different altitudes (sea level up to 1070 in a.s.l.). In accordance with the concept of the CAVM three altitudinal belts can be distinguished. The low altitudinal belt (approx. up to 400 in a.s.l.) is characterised by the occurrence of low Salix glauca shrub -vegetation in "zonal" sites. As such sites are scattered, the lowest belt is dominated by erect dwarf-shrub vegetation and therefore its appearance is similar to that of the middle altitudinal belt (approx. 400-800 in a.s.l.). For further distinction of these belts, plant communities, vegetation pattern and floristics are taken into consideration. In contrast, the high altitudinal belt (above 800 in a.s.l.) can be clearly delimited due to the dominance of graminoids. Snowbed vegetation plays a major part in the distinction of the altitudinal belts. Therefore a detailed description of this vegetation complex is presented. In the lowest belt snowbed vegetation and its typical species are absent. In the middle belt, most of the stands are fragmentarily developed and of small extent. In the highest belt snowbed vegetation covers large areas on northern slopes and is differentiated into several well developed plant communities. In general, the Phippsietum algidae-concinnae Nordh. 1943 occurs in late snowbeds and the Cassiopo-Salicetum (Fries 1913) Nordh. 1936 represents the early snowbed vegetation. Differences in vegetation pattern of snowbed vegetation between the middle and the high altitudinal belt are discussed.