Tundra Biome

About 1/5 of earth is tundra. Tundra is the coldest of all the biomes. The word comes from a Finnish word and means 'treeless plain'. There is arctic tundra and alpine tundra.

The climate is long and very cold, with a short summer.

Arctic tundra is in the northern hemisphere, around the north pole, stretching south to the taiga. The summer growing season lasts about 50 to 60 days. Winter temperatures average -34° C , but the summer temperatures average 3-12° C, which is warm enough for plants and animals to reproduce and grow.

Rainfall varies around the Arctic, but on average yearly precipitation, including melting snow, is 15 to 25 cm.

About a metre under the top layer of soil there is ground that is permanently frozen, called permafrost. In the very short summers, the top level of soil thaws just long enough for plants to grow and reproduce, then become dormant over winter. But the permafrost layer never thaws. Because of this, tundra plants do not have deep root systems. When water soaks the upper soil surface, bogs and ponds may form and provide moisture for plants and small life forms.

Plants in the tundra are low growing, and include:
low shrubs, sedges, mosses, liverworts, and grasses
400 varieties of flowers
lichens

Plants group together to withstand the strong winds and cold temperatures. They are protected by the winter snows. They have adapted so that photosynthesis (getting food from sunlight) can occur in the low light and cold temperatures.

Animals found in the Arctic include:
Herbivorous (plant eating) mammals such as lemmings, voles, caribou, arctic hares and squirrels
Carnivorous (meat eating) mammals such as arctic foxes, wolves, and polar bears
Migratory birds such as ravens, falcons, loons, ravens, sandpipers, terns and snow birds
Insects such as mosquitoes, flies, moths, grasshoppers, blackflies and arctic bumble bees

Animals in the tundra have adapted to survive the long cold winters. They have an extra layer of fat to keep them warm. Many hibernate during the winter when food is hard to find. Others migrate to warmer places to avoid the tundra winter. This means that animal populations in the tundra fluctuate with the seasons. Animals breed and raise their young in the short summer. There are few reptiles and amphibians in the tundra because of the cold .

Alpine tundra is found on mountain tops all over the world, at the high altitudes where trees cannot grow.The growing season is approximately 180 days. Night temperatures are below freezing. The soil in the alpine tundra is well drained so bogs and ponds do not form. The plants are similar to those in the arctic tundra and include tussock grasses, dwarf trees and small-leafed shrubs.

Animals living in the alpine tundra include:
Mammals such as pikas, marmots, mountain goats, elk
Insects such as beetles, grasshoppers, butterflies

Find out more about tundra

Find out about other biomes:
water .. rainforest .. desert .. taiga .. deciduous forests .. grassland

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updated November 2002