Tundra Described
Tundra is an area where the tree growth is hindered by low temperatures and short growing seasons. The term "tundra"
comes from Kildin Sami tundar "uplands, tundra, treeless mountain tract". There are two types of tundra: Arctic
tundra (which also occurs in Antarctica), and alpine tundra. In tundra, the vegetation is composed of dwarf shrubs,
sedges and grasses, mosses, and lichens. Scattered trees grow in some tundra. The ecotone (or ecological boundary
region) between the tundra and the forest is known as the tree line or timberline.
Arctic tundra occurs in the far Northern Hemisphere. The Arctic tundra is a vast area of stark landscape, which is
frozen for much of the year. The soil there is frozen from 25-90 cm (9.8-35.4 inches) down, and it is impossible for
trees to grow. Instead, bare and sometimes rocky land can only support low growing plants such as moss, heath, and
lichen. During the summer, temperatures rise somewhat, and the top layer of the permafrost melts, leaving the
ground very soggy. The tundra is covered in marshes, lakes, bogs and streams during the warm months. Generally
daytime temperatures during the summer rise to about 12 C (54 F) but can often drop to 3 C (37 F) or even below
freezing. Arctic tundras are sometimes the subject of habitat conservation programs. In Canada and Russia, many of
these areas are protected through a national Biodiversity Action Plan. The biodiversity of the tundras is low: 1,700
species of vascular plants and only 48 land mammals can be found, although thousands of insects and birds migrate
there each year for the marshes. There are also a few fish species such as the flat fish. There are few species with
large populations. Notable animals in the Arctic tundra include caribou (reindeer), musk ox, arctic hare, arctic fox,
snowy owl, lemmings, and polar bears (only the extreme north).
Alpine tundra is an ecozone that does not contain trees because it has high altitude. Alpine tundra occurs at high
enough altitude at any latitude on Earth. Alpine tundra also lacks trees, but the lower part does not have
permafrost, and alpine soils are generally better drained than permafrost soils. Alpine tundra transitions to
subalpine forests below the tree line; stunted forests occurring at the forest-tundra ecotone are known as
Krummholz. Alpine tundra occurs in an alpine zone.
Below is a typical food chain for the types of animals you could find on the tundra. From the predators on top all the way down to the producers on the bottom.
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