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Tundra

In physical geography, tundra is an area where tree growth is hindered by low temperatures and short growing seasons. The term "tundra" comes from the Sami language (through Russian), meaning treeless plain.

There are three types of tundra: arctic tundra, antarctic tundra, and alpine tundra. In all of these types, the dominant vegetation is grasses, mosses, and lichens.

Trees grow in some of the tundra. The ecotone (or ecological boundary region) between the tundra and the forest is known as the tree-line or timberline.

See also:

Contents

Arctic tundra


Arctic tundra occurs in the far Northern hemisphere, north of the taiga belt. The word "tundra" usually refers only to the areas where the subsoil is permafrost, which contains permanently frozen water. (It may also refer to the treeless plain in general, so that northern Lapland would be included.) Permafrost tundra includes vast areas of northern Russia and Canada. The arctic tundra is home to several peoples who are mostly nomadic reindeer herders, e.g. Nganasan and Nenets in the permafrost area (and the Sami in Lapland).

The biodiversity of tundra is low: there are few species with large populations. Notable animals in the arctic tundra include:

Due to the harsh climate of the arctic tundra, regions of this kind have seen little exploitation even though they are sometimes rich in natural resources such as oil and uranium. In recent time this has begun to change, and in Alaska, Russia and some other parts of the world the tundra is being ever more subjected to human interference.

Global warming is a severe threat to the arctic tundra because of the permafrost. Essentially, permafrost is frozen bog. In the summer, only its surface layer melts. Should it melt completely, the entire ecosystem would be devastated. The arctic species could not adjust for such a rapid change. Another threat is that one third of the world's soil-bound carbon is in the taiga and tundra areas. When the permafrost melts, it releases carbon more than it can bind. The effect has been observed in Alaska: in the 1970's, the tundra was a carbon sink, but today, it's a carbon source. This aggravates the problem of global warming even further.

See also: Aerial winter photo of typical arctic tundra


Antarctic tundra

Antarctic tundra occurs on Antarctica and on several antarctic and subantarctic islands, including South Georgia and the South Sandwich Islands and the Kerguelen Islands. Antarctica is mostly too cold and dry to support vegetation, and most of the continent is covered by ice fields. However, some portions of the continent, particularly the Antarctic Peninsula, have areas of rocky soil that support tundra. Its flora presently consists of around 250 lichens, 100 mosses, 25-30 liverworts, around 700 terrestrial and aquatic algal species, which live on the areas of exposed rock and soil around the shore of the continent. Antarctica's two flowering plant species, the Antarctic hair grass (Deschampsia antarctica) and Antarctic pearlwort (Colobanthus quitensis), are found on the northern and western parts of the Antarctic Peninsula.

In contrast with the arctic tundra, the antarctic tundra lacks a large mammal fauna, mostly due to its physical isolation from the other continents. Sea mammals and sea birds, including seals, penguins, inhabit areas near the shore, and some small mammals, like rabbits and cats, have been introduced by humans to some of the subantarctic islands.

The flora and fauna of Antarctica and the Antarctic Islands (south of 60 south latitude) are protected by the Antarctic Treaty.

Alpine tundra

Typical alpine tundra
Enlarge
Typical alpine tundra

Alpine tundra occurs at high enough altitude at any latitude on Earth. Alpine tundra also lacks trees, but does not usually have permafrost, and alpine soils are generally better drained than permafrost soils. Alpine tundra transitions to subalpine forests or Montane grasslands and shrublands below the tree-line; stunted forests occurring at the forest-tundra ecotone are known as Krummholz.

Notable animals in the alpine tundra include:

Tundra ecoregions

Antarctic ecozone
Marielandia Antarctic tundra Antarctic Peninsula
Maudlandia Antarctic desert eastern Antarctica
Scotia Sea Islands tundra

South Georgia and the South Sandwich Islands,South Orkney Islands,

South Shetland Islands,Bouvet Island
Southern Indian Ocean Islands tundra Crozet Islands,Prince Edward and Marion Islands , Heard Island,Kerguelen Islands,McDonald Islands
Australasia ecozone
Antipodes Subantarctic Islands tundra Australia
New Zealand
Nearctic ecozone
Alaska-St. Elias Range tundra Canada,United States
Aleutian Islands tundra United States
Arctic coastal tundra Canada,United States
Arctic foothills tundra Canada,United States
Baffin coastal tundra Canada
Beringia lowland tundra United States
Beringia upland tundra United States
Brooks-British Range tundra Canada,United States
Davis Highlands tundra Canada
High Arctic tundra Canada
Interior Yukon-Alaska alpine tundra Canada,United States
Kalaallit Nunaat high arctic tundra Greenland
Kalaallit Nunaat low arctic tundra Greenland
Low Arctic tundra Canada
Middle Arctic tundra Canada
Ogilvie-MacKenzie alpine tundra Canada,United States
Pacific Coastal Mountain icefields and tundra Canada
United States
Torngat Mountain tundra Canada
Palearctic ecozone
Arctic desert Russia
Bering tundra Russia
Cherskii-Kolyma mountain tundra Russia
Chukchi Peninsula tundra Russia
Kamchatka Mountain tundra and forest tundra Russia
Kola Peninsula tundra Norway
Russia
Northeast Siberian coastal tundra Russia
Northwest Russian-Novaya Zemlya tundra Russia
Novosibirsk Islands arctic desert Russia
Scandinavian Montane Birch forest and grasslands Finland,Norway,Sweden
Taimyr-Central Siberian tundra Russia
Trans-Baikal Bald Mountain tundra Russia
Wrangel Island arctic desert Russia
Yamalagydanskaja tundra Russia



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