Tundra
by Hinde LiepmannsohnThe word Tundra finds its origin in a Finnish word tunturia, which means treeless plain. In fact, the tundra is a plain with a permanently frozen soil that can be 9 inches to 3 feet thick. Tundra is located in the Arctic regions. Of all biomes, the tundra biome is the coldest, with extreme temperatures that can reach minus 25 degree Fahrenheit (-31°C). It is also the simplest of all biomes because only limited life forms can subsist in its environment. The dead organic matter constitutes the pool of nutrients, resulting in nitrogen and phosphorus aided by low precipitations. Because of these factors, no deep rooted tundra plant can grow on this soil. Yet there are about 1700 species of tundra plants mostly perennial forbs, dwarfed and stunted shrubs, liverworts, or grasses. They constitute the food web for the herbivorous animals and other tundra animals. The tundra only has two main seasons: winter and summer. The spring and fall last only short periods of time.
Tundra Food Web
There are permanent resident species and migratory ones. Some of the most common permanent tundra animals found are some bird species as well as mammals such as the Arctic fox or the Arctic hare or caribous. Most tundra animals are large. The weather conditions of the tundra biome require these species to have a large amount of feathers or fur to provide thick body insulation. In addition, as winter covers the land, their insulated coats turn from summer brown to entirely white. The short growing season enables these animals to feed enough to form the thick layer of fat. It will provide them both energy and a protection against the cold.
In the tundra biomes, the animal population varies in size, sometimes in response to the change in population in other species. For example, the lemming consumes some of the plain vegetation. During the summer when there is food, they breed with astounding speed. One female produces five or six babies in a litter and does so, four or five times in a single season. In a few months, she may have produced thirty young. The babies grow so quickly that the first to be born in the spring can themselves reproduce before the winter returns. If vegetation is insufficient, some of the newborn will die and the population will decrease.
Fluctuations in the number of predators can also greatly affect species existence. The snowy owl is a predator of the lemming. It will emigrate from the tundra if the lemming is scarce, and might travel south, sometimes beyond South-Virginia. Many of these snowy owls die when they attempt to return to the plains.
The migratory species such as the caribou will only remain in the tundra plains during the summer season. The herd moves as much as 50 miles a day (over 80 km) following the same route each year. In places, paths have been worn 18 inches deep (45 cm) where the animals have passed century after century. They have to keep traveling in order to find enough food to sustain them all. Caribous will migrate south to avoid winter but will return to the plains to breed when the winter ends. The Arctic tern, a white seabird, migrates from the Arctic where it breeds, to the Antarctic.
The location of the tundra affects its environmental conditions. There two major types of Tundra: The Arctic and Alpine Tundra
The Artic Tundra
It is the youngest on earth as it was formed only 10000 years ago while the earth formation started 12 billion years ago. Located in the northern hemisphere at latitudes 55° to 70° north, it covers and encircles the North Pole. Found on about 20% of the Earth's surface, the temperature averages -34° F in winter, and between 37° F and 54° F. (3 to 12 °C) in the summer. Depending on its location on the Pole it is referred to as the high, middle or Low Arctic tundra.
The high Arctic Tundra is found on islands located on the Arctic Ocean. The Arctic Archipelago and some of the Queen Elizabeth Islands constitute this tundra biome. On its grounds are found mosses and lichens that grow on rock surfaces, which are a vital part of the tundra food web for herbivorous mammals and other tundra animals. The temperatures range between 90° F in the northern parts to -9° F in the South (32 to -23 °C). It is a dry, cold climate, with very little precipitation. One kind of tree manages to live on these lands in surprisingly large quantity: it is the Arctic willow growing extremely slowly lying flat on the ground.
The middle Arctic tundra is only found on the leveled plains of the Arctic Coasts, in the northern territories, and at outmost northern part of Quebec. The north central area has temperatures from 32 in the summer to -22° F in the winter (0 °C to 30 °C). Rock polygons are created as a result of the thawing of frost of the ground. The energy that generates from its activity will permit microhabitats to develop and give life to Arctic tundra plants; the drenched center of these polygons enables moss to grow, while the dryer circling ring allows for the formation of forbs. These tundra plants give the effect of a patterned ground.
The Low Arctic tundra is the last type. It is where the driest soil but also where the thickest permafrost can be found. It is located at the most extreme northern part of the Labrador, extending to the Eclipse River, at the border of Quebec. Some woody shrubs can grow in its extremely cold conditions. No trees can grow on its soil.
The Alpine Tundra
Located on the higher slopes of the Northern Hemisphere Mountains, the alpine tundra offers a climate and environment different from that of the Arctic. Although the seasons are different, in some areas, the cold temperature and thinner soils allow for tundra plants to take over where trees cannot grow. The alpine tundra has a short growing season and temperature go below freezing at night. The major difference with the Arctic tundra is its dry soil.
In addition, there are some lands in Antarctica that resemble the tundra biome on the Northern hemisphere but with much colder temperatures. The soil is constantly covered with snow and ice. As a result, it is not an ideal environment for the typical tundra vegetation to form or for the typical tundra animals to subsist.
Tundra Biome Endangered
The tundra food web is limited to a few numbers of tundra plants and animals. Disrupting this equilibrium is an easy process; the disappearance of one species could affect the entire ecosystem. In addition, in Alaska for example, natural resources have brought more human interference. Finally, global warming seems to represent to biggest threat to this ecosystem, be thawing the permafrost that is typical of Tundra, and devastated this biome.
