Circumpolar Arctic Elevation Belts
Very steep bioclimate gradients occur in mountains, so these areas are mapped as complexes of elevation belts. Mountainous areas of the map are shown with hachures; the background color indicates the nature of the bedrock, and the color of the hachures indicate the bioclimate subzone at the base of the mountains.
Color scheme for elevation belts in mountainous areas. Mountain complexes were mapped using a diagonal hachure pattern. The background color indicates the nature of the bedrock (magenta (left side) for noncarbonate rocks, blue-purple (right side) for carbonate bedrock), and the color of the hachures indicate the bioclimate subzone at the base of the mountains (purple, Subzone A; blue, Subzone B; green, Subzone C; yellow, Subzone D; and red, Subzone E). The code numbers in mountainous areas have an additional small alphabetic suffix that indicates the subzone at the base of the mountains. For example, carbonate mountains (map code B4) in Subzone E have a small e added to the (map code B4e). Mountains in subzone E could have up to six elevation belts (if the mountains are high enough). The lowest belt, Belt e is dominated by low-shrub tundra (S2); the next higher belt, Belt d has erect dwarf-shrub tundra (S1); Belt c has prostrate dwarf-shrub, herb tundra (P1); Belt b has rush/grass, forb, cryptogam tundra (G1); Belt a has cryptogam, herb barrens (B1); and the nival belt is snow and ice covered. The belts are 333 m intervals, which correspond about a 2 °C to a decrease in the mean July temperature or about –6 °C per 1000 m elevation as predicted by the ecological adiabatic lapse rate (Barry & Chorely 1987). Since only one elevational belt can be represented on each polygon, the color of the lowest belt is used for the polygon although higher elevational belts may exist in that polygon. (CAVM Team 2003, with permission of USFWS).
A full explanation of the legend and map units is in Walker et al. 2005.
elevation belt in the subzones
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