Tundra: Cold Boggy Plains of the Far North

Tundra are treeless plains that occur under the harsh climates of low rainfall and low average temperatures. The dominant vegetation includes grasses and their relatives (sedges), mosses, lichens, flowering dwarf shrubs, and mat-forming plants.

There are two kinds of tundra: arctic which occurs at high latitudes, and alpine, which occurs at high elevations. The vegetation of both is similar, but the dominant animals are different. Arctic tundra typically have important large mammals, birds, and insects; in alpine tundra, the dominant animals are small rodents and insects. Alpine tundra occupy comparatively small, isolated areas, whereas arctic tundra cover the large territories required for populations of large mammals.

Parts of tundra have permafrost, which is permanently frozen ground. Such area are extremely fragile ecologically; when disturbed by such activities as the development of roads, permafrost areas may be permanently changed or may take a very long time to recover. As the environment becomes more harsh, the vegetation grades from dwarf shrubs and grass like plants to mosses and lichens, and finally to bare rocks surfaces with occasional lichens. The extreme tundra occurs in Antarctica, where the major land organism in some areas is lichen that grows within rocks, just below the surface.