Tundra is a large region located in the northern hemisphere of the world. It is also known as the Barren Land and it lies principally along the Arctic Circle, on the coast and islands of the Arctic Ocean, and to the north of the coniferous forest belt. In Canada, the southern boundary extends from the Mackenzie Delta to southern Hudson Bay and northeast to Labrador. In north Siberia the tundra is the wildest area and it reaches as far north as 60. latitude.
For most of the year the mean monthly temperature of the tundra region is below freezing and the growing season averages only 2 weeks per year. The tundra has long and severe winters and short summers. The winters consist of strong winds and blizzards while the summers are relatively warm. But, even in the hottest days of July the temperature does not rise above 10.C. Although there are relatively high temperatures in the summer days, the ground never thaws due to the fact that the subsoil is permanently frozen, this is known as permafrost. Precipitation is spread evenly during the year and is slight, varying from 20cm 30cm. Due to its northern location the tundra gets varied amounts of sunlight at different times of the year. In the summer, the sun remains above the horizon 24 hours a day for up to 85 consecutive days, and in the winter, the sun remains below the horizon 24 hours a day for as long as 67 consecutive days.
Permafrost limits the rooting depth of plants and forces surface water to drain before it can seep into the soil. Because of this, extensive marshes and lakes are formed. During the summer, sedges, mosses, and lichens appear, along with some flowering plants. Due to the heavy winds, there is an effective seed dispersal of tundra plants.
Some of the few animals that inhabit the tundra are the Caribou, the arctic fox, the snowshoe rabbit, the polar bear, and the lemming. In Russia s tundra there is a small human population mostly consisting of the Nensty and the Komi, while in North America, Inuits inhabit the tundra.
The tundra is one of the main producers of oil and natural gas. It is responsible for over one-fifth of the American output of oil and natural gas and an even larger proportion in Russia. As a result, human beings migrate to the north in search of money, which has the obvious consequences, pollution, destruction of habitat etc. The pipelines also have a direct affect on the environment. There are oil and gas spills that physically harm the wildlife, pollute the water and destroy vegetation. Human involvement in the arctic is expanding, furthering the damage that has already been done.
Lemmings play a vital role in the ecosystem of the tundra. For example, every four or five years there is a boom in the lemming population. Large quantities of vegetation then are consumed which, causes not only lemmings to starve to death but, also other herbivores in the area. Synonymous with the growth and decline of the lemming population, is the inevitable growth and decline of the predator population, e.g. foxes, wolves, etc. Eventually, the decomposing bodies of the dead animals replenish the soil and the animal populations again flourish only for the cycle to repeat.