What is Tundra Biomes? | Types, Definition, Structure, Function & Facts
What is Tundra Biomes?
The tundra biome is a cold, treeless plain where harsh conditions make it difficult for plants and animals to survive. About 20% of the earth’s surface is covered with tundra.
Characteristics of the Tundra Biome
It’s Cold – The tundra is the coldest place in the biome. The average temperature in the tundra is around -18°F. It is much colder in the winter and warmer in the short summer.
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It’s Dry – The tundra receives about the same amount of rain as the average desert, about 10 inches per year. Mostly snow.
Permafrost – Below the soil surface, the ground is permanently frozen all year round.
It is barren – The tundra has few nutrients to support plant and animal life. It has a short growing season and a slow rotting rate.
Two Types of Tundra
Alpine Tundra – Alpine tundra is an area of high land in the mountains above the tree line.
Arctic Tundra –The Arctic tundra lies far north in the Northern Hemisphere along the Arctic Circle. There are large tundra regions in northern North America, northern Europe and northern Asia.
Tundra Seasons
The tundra has two distinct seasons: long winters and short summers. Far to the north, the tundra has long nights in winter and long days in summer.
Winter lasts about 8 months and is very cold. In the middle of winter, the sun may not rise for weeks. The tundra is frozen and often covered with snow during the winter and will reach temperatures of -60 degrees Fahrenheit.
Summer is shorter and marked by another extreme of the sun, which does not set. In midsummer, the sun will rise in 24 hours. During the summer, temperatures can reach 50 degrees Fahrenheit causing snow to melt in areas and form wetlands.
What is Permafrost?
Permafrost is a layer of soil below topsoil that is frozen year-round. This layer is usually only a few feet above the surface. Permafrost prevents plants from growing on tundra because trees must have deep roots and they cannot grow on frozen ground.
Plants in the Tundra
Plants that grow in the tundra include grasses, shrubs, herbs, and lichens. They grow in groups and stay underground to protect themselves from icy winds. They tend to have shallow roots and bloom rapidly during the short summer months.
Most tundra plants are perennials that regrow every year from the same root. This allows them to grow during the summer and conserve nutrients while they are dormant during the winter. They also tend to have hairy stems and dark leaves. This helps them absorb energy from the sun.
Animals in the Tundra
The tundra has more animal activity in the summer than in the winter. Indeed, most birds migrate south in the summer, the insects that lay eggs wait until summer to hatch, and some mammals hibernate during the winter. There are even animals, like reindeer, that migrate south during the winter.
Some animals have adapted to wintering on the tundra. Some change their coat from brown in the summer to white in the winter to blend in with the snow. These include arctic hares, ermines and arctic foxes. Other animals that are active during the winter include snowy owls, musk cows, and ptarmigans.
Facts about the Tundra Biome
The tundra is a very fragile biome that shrinks as the permafrost melts.
Lemmings are small mammals that burrow in the snow to eat grass and moss during the winter.
Polar bears come to the tundra in the summer, where they give birth.
Tundra animals tend to have small ears and tails. This helps them lose less heat when it’s cold.
They also tend to have large feet, which help them walk in the snow.
Plants that grow in tight groups to protect themselves from the cold are sometimes called cushion plants.
The Alaskan Inuit lives on the tundra.