High Arctic Vegetation

Vegetation is the basic element of all terrestrial ecosystems, therefore vegetation types are fundamental in the classification of terrestrial biota across all scales, from communities through ecosystems and finally, biomes. The Arctic tundra biome is geographically restricted to a relatively narrow strip around the margins, including the archipelagos, of the Arctic Ocean (Halliday, 2002). The High Arctic Vegetation (HAV) is characterized by low-growing vegetation of low complexity, mostly comprising bryophytes (mosses and liverworts), lichens, small stature vascular plants and algae (micro- and macroalgae) that together constitute the least diverse terrestrial ecosystems in the Northern Hemisphere. The HAV represents a component of the High Arctic bioclimatic zone and the northern part of the Arctic tundra biome (Thomas et al., 2008; Barry et al., 2013). The main driving factor influencing the complexity and productivity of tundra vegetation is a latitudinal/environmental gradient, based on which the zonal structure of the Arctic biome can be differentiated (Elvebakk, 1999; Walker et al., 2005). According to the Circumpolar Arctic Vegetation Maps, the definition of the High Arctic followed here includes the three northern-most subzones (A—Arctic polar desert; B—northern Arctic tundra; C—middle Arctic tundra), which are distinguished based on botanical and climatic criteria (Elvebakk, 1999; CAVM Team, 2003; Walker et al., 2005) (Fig. 1 and Table 1).