Tundra ecosystems are habitats found in cold treeless areas near the Arctic or Antarctic and on the top of mountains. There is very little rain, and the temperatures are very cold. There is much wind also. This land is covered by snow most of the year. However, in summer, flowers bloom for a brief time. Tundra exists in both the northern hemisphere and the southern hemisphere. The word tundra means a barren treeless land. The tundra ecosystem takes up about ten percent of the surface of the earth.
The alpine tundra is in the mountains, above the tree line. This tundra ecosystem begins at an elevation of between 11,000 and 11, 500 feet. Mountain goats, sheep, marmots and certain birds live in this alpine land. They eat low-lying bushes and insects.
In the alpine tundra, flowering plants survive by growing in depressions in the rocks. Cushion plants look like moss because they grow so close to the ground. They may have very deep roots for stability against the fierce winds. Some of the flowering plants have dense hairs on the stems to protect against low temperatures. Some plants take two years to bloom, one to produce buds under the ground and one to bloom above. Some flowers have a red pigment which can change the sun's rays into heat for them. Temperatures vary from 37-53 degrees Fahrenheit in summer to usually not below zero in winter in the alpine tundra.
Alpine tundra can be found all over the world where the mountains are too high to sustain trees due to the intense cold and strong winds. The elevation where tundra appears is usually higher near the equator than near the poles.
The Arctic tundra ranges across northern Canada, Scandinavia and northern Asia. Its temperatures range from -25 degrees Fahrenheit in winter to +40 in summer. Polar bears and caribou inhabit the Arctic tundra, while seals and penguins live in the Antarctic tundra. Usually, temperatures get above the freezing mark for at least once a month a year, allowing for some plant life to exist. The summer lasts for fifty to sixty days. Currently, the sun shines twenty-fours a day.
The caribou, elk and musk ox migrate south from the Arctic tundra in winter and return in the summer months. They bring with them predators like wolves and bears. The Arctic foxes and hares have thick white coats for protection against the winter weather. This white hair is twice the length of its brown summer hair.
Because the floor of the Arctic tundra remains mostly frozen, it is called permafrost. The permafrost extends over fourteen hundred feet into the ground. This type of ground cover prevents the growth of trees which would need to put down deep roots. Permafrost does not occur in alpine tundra areas.
Lack of sunshine, cold temperatures, and fierce winds prevent photosynthesis from taking place. Moss and lichens are the main types of plants in these areas. In the southernmost part of this area, the top layer of the permafrost melts in the summer and marshy bogs form on top of the snow. Insects and birds return and live around these marshy areas.
The Antarctic tundra is not at all as extensive as the Arctic tundra. Most of the area is covered with ice all the time. In both the alpine and Arctic tundra areas, a cycle of freezing and thawing occurs every year. Plant life is influenced by soil drainage, temperature and the time the melting occurs. Most of the flowers are perennials (come up every year) and bloom immediately after sprouting.
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