Tundra

The tundra is a geographical region that is a cold, treeless, boggy (wet, spongy ground) plain with a permanently frozen layer of subsoil. Its harsh conditions will not support a wide variety of species. Tundra occupies approximately one-fifth of Earth's land surface.

The tundra can be found only in the extreme northern latitudes where snow melts only in the summertime. It has extremely long, cold winters and short, cool summers, along with regularly low precipitation. Despite receiving barely more rain than a desert does, it is among the wettest landscapes on Earth. This is because it is usually overcast, which minimizes evaporation. All tundra have permafrost, which is a layer of permanently frozen earth that lies just below the surface. This permafrost (permanently frozen subsoil) also prevents water from draining downward. For about fifty days in the summer, the tundra has temperatures warm enough to partially thaw the permafrost. The name tundra comes from the Finnish word tunturi meaning "completely treeless heights." All tundra are treeless, mainly because tree roots could only spread horizontally along the surface of the ground since they cannot penetrate the permafrost. These roots would therefore not be able to anchor themselves and grow tall.

PLANT LIFE IN THE TUNDRA

As with every demanding climate, the plants and animals that live in the tundra have adapted to it in order to live. The soil that lies above the permafrost is a thin layer of cold, moist earth that contains little nutrients for plants. The cold kills off most of the bacteria, so decomposition (breaking down of waste) barely occurs. The common plants found in all parts of the tundra are blankets of fast-growing moss and lichen. Both are able to grow or go dormant at any time and can quickly respond to any sudden weather change. Wildflowers do bloom, however, sometimes through the melting snow so as to take full advantage of the short summer growing season.

ANIMAL LIFE IN THE TUNDRA

The animals that survive in the tundra are also well-adapted to its demands. The larger animals, like the musk ox and polar bear, are well insulated by thick fur. Other predators like the Arctic wolf, wolverine, peregrine falcon, snowy owl, and white fox, prey on lemmings and Arctic ground squirrels. Caribou also migrate (seasonally move) from the taiga (coniferous forest) to the tundra in the summertime in search of food. Many birds migrate north to the tundra in summer to nest and feed on heavy swarms of insects. There are no reptiles or amphibians in the tundra.

Because of its scarce resources and delicate balances, the tundra is one of nature's more delicate biomes (particular types of large geographic regions). It has been shown that the tundra is most susceptible to environmental damage, mainly because it takes so long to regenerate after being disturbed. Ecologists know that even small disturbances can have immediate and devastating chain reactions throughout the entire system.

[See alsoBiome ]