Terrestrial Biome - Tundra
The Tundra biome is the coldest climate biome on earth with an yearly average temperature less than 10 to 20 degrees Fahrenheit and precipitation (mostly in the form of snow) less than 100 millimetres per year. The tundra has short summers lasting from May to July when temperatures only rise to about 50 degrees Fahrenheit.
However, this 'warm' summer produces periods of almost 24 hour daylight, so plant growth can be explosive. In the short summers, the snow and ice melt to leave pools of meltwater. The layer of earth beneath the tundra is frozen all year long. This is called the permafrost. Tundra winters are long, dark and extremely cold for 6 to 10 months of the year. Fierce winds blow while snow and ice cover the ground. Even the sea freezes as the temperature gets colder.
Tundra is found in the regions just below the ice caps of the Arctic, extending across North America, to Europe, and Siberia in Asia. Much of Alaska and about half of Canada are in the tundra biome, this is called the Arctic Tundra.
Tundra biome is also found at the tops of very high mountains elsewhere in the world, this is known as Alpine Tundra.
Alpine tundra is located on mountains throughout the world at high altitude where trees cannot grow. The growing season is approximately 180 days. The temperature at night is usually below freezing. Unlike the arctic tundra, the soil in the alpine is well drained. Some plants are able to survive in the tundra biome. These plants are small and they stay near the ground to avoid the strong wind and cold temperatures. Hairy stems help to keep some plants warm.
Plants in the tundra do not come alive until summer when the conditions are just right for growth. They spend most of their time in the snow. The only tree that grows in the tundra is the dwarf willow tree. It grows to a maximum of four inches tall.
The word tundra derives from the Finnish word for barren or treeless plain land.
Animals and birds that live in the Tundra Biome
A large variety of animals live in the tundra for the whole year. They have special adaptations that allow them to survive in the winter weather. Some of these include short legs, long hair and a coat of thick fur. They have short tails and large, furry feet. Animals such as mammals and birds also have additional insulation from fat.
Many animals have white fur which camouflages them against the snow. Every ten or thirteen years, the small mammals in the tundra breed in large numbers. The larger animals also grow in number because of the increase in their food supply. Eventually the small mammals run out of plants to eat and many die. The larger animals begin to die and then the plants can grow back. Animals are adapted to handle long, cold winters and to breed and raise young quickly in the summer.
Many animals hibernate during the winter because food is scarce. Some animals migrate south in the winter, particularly birds. Reptiles and amphibians are few or absent because of the extremely cold temperatures. Because of constant immigration and emigration, the population continually fluctuates.
Below are just some of the animals that inhabit the Tundra biomes.
For animals that live in the Alpine Tundra, click here!