Scenarios of Biodiversity Changes in Arctic and Alpine Tundra

Abstract

Arctic and alpine tundra, defined as those areas that lie to the north of the latitudinally or altitudinally controlled limits of tree growth (Gabriel and Talbot 1984), currently occupies approximately 8.3 × 106km2. The tundra biome is characterized by low biomass and species diversity relative to other biomes, and the spatial distribution of species of all groups is strongly structured by physical factors (Chapin and Körner 1995). About 2.3 × 106km2 (28%) of the total is occupied by ice, primarily the continental glaciers of Greenland and Antarctica. The remainder consists of a combination of shrub-dominated tundra (about 25%) and herbaceous-dominated tundra (about 47%). Herbaceous-dominated tundra is usually subdivided by ecologists into true tundra (or alpine tundra in the mountains) and polar desert (which is somewhat analogous to the alpine nival zone). The IMAGE model (Alcamo 1994) upon which this volume is based recognizes shrub tundra (i.e., woody tundra), tundra, and ice.