Polar desert
- Ice sheets
- Polar Cold Desert
- Alpine cold desert
- ( Note: Click on the link for a great view of the original map "Vegetation zones " ")
Cold desert at Huey Creek, a melt-water flow in the Antarctic dry valleys
> 10 % largely to nature <5% of anthropogenic overprinted
Russian Arctic ( RUS) 14.26 thousand km ² Tupungato (ARG ) 883 km ² Barwick / Balham ( ATA) 480 km ² Tajikistani NP ( TJK ) 26,117 km ²
Cold desert: Climate diagrams
Cold Desert ( also frost rubble desert or territory ) is a term used in geography and called generalizing the type of landscape of the global scale level.
From the perspective of Geobotany ( plant geography ), the cold desert is a natural type of vegetation is mainly produced under the conditions of Eisklimas. In their erdumspannenden ( geozonalen ) expansion, the cold desert is among the vegetation zones. In addition, comparable plant formations are found worldwide in the high levels of the mountain, which can be as non- zonal vegetation types assigned to the cold deserts.
From the perspective of ecology the cold desert [Note 2] is a global ecosystem, which is referred to as either biome or ecoregion. , Which in turn subdivide the globe for seamless Polar Zonobiom or the Polar / Subpolar ecozone.
The ice deserts ( ice sheets and glaciers ) of the earth be considered biogeographically not attributed to the cold deserts, since no plants and animals can live longer.
Characteristic of the various forms of cold desert is an open, rocky or sandy and for the most part almost vegetation-free landscape over permafrost. In many cases the lichen crusts are the only visible living creatures on the rocks. In addition, protected areas are mainly found mosses and grasses.
- 6.1 WWF ecoregions
Distribution and condition
The northern ( Arctic ) vegetation zone of the cold desert ranges in their maximum expansion of about 83 ° north latitude ( Cape Morris Jesup on Greenland) to 66 ° ( the Arctic Circle on Baffin Island ). The southern ( Antarctic ) zone extends from 85 ° S latitude ( ice-free peaks of the Transantarctic Mountains ) to about 63 ° ( Graham Land on the Antarctic Peninsula ). Because of the few areas of land in the South hemisphere the local cold desert makes up only a small part of the entire area. The cold deserts go poleward into the zone of ice sheets and towards the equator in the tundra over.
The non- zonal alpine cold deserts are used worldwide in virtually all high mountains above the mats before and here are the nivale height level.
The largest undestroyed cold deserts of the world lie on the Queen Elizabeth Islands in Canada. In the Tibetan Plateau, the largest areas lie outside the polar zone.
Without the influence of the people today would be about 2% of the terrestrial land surface cold deserts. ( Refers to the icy wastes with a, one arrives at a total of 10%) In fact, the beginning of the 3rd millennium about 85 % of the cold deserts in a largely unaffected, natural state. These areas are uninhabited. About 10% are still affected to nature and relatively small. These areas are mainly in the vicinity of coastal settlements or in high mountains. Less than 5% have been changed extensively and overprinted by anthropogenic landscapes. [Note 3]
Characteristics
As a cold desert is called territories in transition from tundra to the frozen wastes containing less than 10%, but have more than 1% of vegetation cover. The year-round frozen permafrost prevents the penetration of roots and the air temperature is so cold that plant growth is severely restricted. Therefore, can also be found for animals only very limited habitats. Another feature of the polar deserts are cold dry air and high winds ( blizzard ). Due to the lack of protection of plant cover and the resulting humus layer occurs in the freezing temperatures for so-called frost weathering of rocks. The product is called " frost rubble ".
Icy wastes
About nine percent of the earth 's land surface are less than one ice sheet, which limits the ice-free cold deserts. 16 % of which is on the Greenland ice sheet. The largest desert of ice on Earth is Antarctica, which accounts for around 83 % of it. In the Antarctic inland, it is extremely dry because the cold air can hold very little moisture. Rainfall often go down to the Antarctic coasts and not reach the central regions. The ice sheets located there get in often only a very thin top layer of new ice added, so powerful ice accumulations in depressions often consist of very old ice. Rarely, through drifts and sublimation of ice to open, ice-free desert landscapes that consist of barren frost rubble fields or rocky ground. One calls these areas " Antarctic dry valleys ".
In all mountainous ice deserts also occur so-called nunataks; Hilltops protrude above the ice. As a habitat for lichens and algae both the nunataks, as well as the Antarctic dry valleys are again attributed to the cold deserts.
Climatic conditions
The cold deserts of the world lie in the polar climate zone and are therefore usually characterized by very cold climates with long, cold winters and short, cool summers. In the coldest month, the increase in mean temperatures generally do not exceed 0 ° C; wherein the minimum is below -50 ° C. Nine to 12 months is snow. The warmest month is on average barely above 5 °; in part, the temperature remains even in summer below -10 ° C. However, maximum temperatures of 20 ° C are possible, even in these high latitudes. The long-term average temperature is between -30 ° C and generally below 0 ° C For the polar cold deserts also is added one aggravating for plant growth, very little sunlight, which is however compensated by the midnight sun, partly in midsummer.
With average values below 100 to 200 mm, the annual totals of precipitation are low to very low. Since they almost exclusively fall as snow, the air is also called nival. The long period of frost and low temperatures lead to a low evaporation rate, so that the climatic water balance on the ground despite the low rainfall humid ( moist) is.
The growing season is very short with less than 30 days.
After the effective climate classification of Köppen / Geiger is referred to in the aforementioned conditions the so-called Eisklima ( abbreviation: EF ).
More Features
In the cold deserts of the very poor soil formation on rock and sand remains mostly in Rohbodenstadien.
The cold deserts are deserts in the narrowest sense - almost lifeless frost rubble deserts, which mostly consist of gravel and boulders. Typical of the transition region to the tundra is the restless ground relief that is often characterized by peaks and troughs or network-or ring- like arrangement of walls. These are so-called frost -patterned ground. In essence, leading the short-term, every year again held up and defrost the soil above the permafrost to these unusual structures.
Through the above-mentioned abiotic factors is the existing amount of biomass is extremely low (less than 2 t / ha of dry matter). Per year occur 1.5t.
Flora
Northern Hemisphere
Only 0.4 % of all vascular plants on earth live in the Arctic. In addition, the distribution of almost all living species there is not confined to the polar regions! The plant density and diversity decreases poleward. In the cold desert mosses remain and a few flowering plants of the isolated, insular locations dwarfed ( 2-5 cm) and form a coherent network of roots from. Such sites occur, for example in parabolartigen depressions whose shape focuses the incident solar radiation. Two typical flowering plants that are occurring at the edge of the ice sheets to hard the Purple saxifrage and Arctic poppies. However, the dominant life forms of the cold desert, algae and lichen - a symbiotic communities from green algae and fungi. Lichens are absolutely frost-hardy. The lichens that live on rocks and extremely hard, often reminiscent of maps patterns form ( map lichen ), photosynthetically remain active even in freezing temperatures. On rock lichens are important pioneer organisms, which sit either the rock or even penetrate into the stone.
Southern Hemisphere
Before man einschleppte a handful of neophytes, grew up in and around the Antarctic only two flowering plants: the Antarctic hairgrass ( Deschampsia antarctica) and Antarctic Perlwurz Dianthus ( Colobanthus quitensis ). By far the largest part of the Antarctic cold desert is up to a few lichens of vegetation. The number of lichen species here is much lower in the Arctic.
Fauna
The fauna of the cold desert is even more sparse than the plant world and particularly focused on the coastal areas. Here are seals on land and breed many seabirds. The symbolic animal of the Arctic cold desert is probably the polar bear, while there are the penguins in the Antarctic.
Colonization
Except for the coastal areas of the highly polar islands of Canada, which were inhabited by Inuit, the hostile cold deserts were never residence of indigenous peoples. Only the Europeans have since the end of the 19th century established a few research or military stations, which are partly inhabited long-term. Then there are the winter sports facilities in the frost rubble areas of some high mountains.
Use, development, threat and conservation
Agricultural cultivation in the cold desert is not possible because of the climate. Since time immemorial, is the only form of traditional use hunting and fishing on the coasts of these areas.
Among the cold deserts are rich mineral resources, which have not been promoted. The future improved by climate change accessibility of the Arctic by sea has set in motion to the effect in the countries bordering considerations. However, the obstacles have been so large and costly that the short and medium need not be expected to exploitation.
Throughout the Antarctic may provisionally take place no resource extraction in the framework of the " World Park Antarctica " until 2048.
The biggest change for the cold deserts resulting from global warming, which is located in the high latitudes of the North, well above the average. The ice sheets will shrink and make room for more frost rubble areas, while the Tundra is very slowly spread toward the poles.
The species diversity ( and beyond biodiversity) the cold desert is extremely low ( 200-600 species per ha).
According to the IUCN approximately 7 % of the total were 2003 protection.
Referred to in the infobox exemplary large protected areas each contain a maximum share of the vegetation type desert cold. Moreover, it is only to areas where the preservation ( or restoration ) of a prospective natural state as possible is paramount and that can be viewed by international standards as strictly protected.
Subdivision
Because of their similarity and the extremely low biodiversity a further breakdown of the cold deserts in other plant formations is hardly made. Only one division in polar and alpine cold desert makes sense because of the different climatic conditions and to the small area of frost debris areas in the high mountains.
WWF ecoregions
The WWF U.S. has made an exemplary global classification by ecoregions. The boundaries of these regions are based on a combination of different biogeographic concepts. They are particularly well suited to the purposes and objectives of nature conservation. [Note 4]
The term cold desert ( Polar Desert ) belongs to the WWF - categories to the main biome ( "Major habitat types" ) of the tundra. 37 ecoregions ( " Ecoregions " ) subdivide this major biome. Of these four regions are considered as cold deserts ( " polar deserts in the Barents - Kara Sea u ", " polar desert of the New Siberian Islands ," "Polar Desert Wrangel Island " and "Polar Desert East Antarctica "). In six other ecoregions make cold deserts of substantial portions of the surfaces.
Cold deserts on other celestial bodies
The surface of many planets is also likely to meet our vision of a cold desert. However, the only known planet with proven kältewüstiger surface of Mars. He is also very dry, although there are proportionately to the Martian poles and water ice.
The driest place you know, the Earth's moon. Because of its lack of atmosphere temperatures vary between -233 and there moon day 123 ° C. A place on the moon thus fluctuates in 28 days between hot stone desert and extreme cold desert. By far the largest part of its surface is almost completely devoid of water molecules.
Gallery
The Ekblaw Lake in the cold desert of Quttinirpaaq National Park
Arctic poppies on Ellesmere Island
Nunataks Osborn Range on Ellesmere Island
Franz Josef Fjord in northeast Greenland
Cold desert at Franz Josef Fjord
Stone rings of frost patterns on soil Spitsbergen
The Noa Lake in King Oscar Fjord, Greenland
View from Sømandsfjeldet on the Kong Oscars Havn with Tasiilaq
Cape Tegethoff on the island Hall, Franz Josef Land
Fairhaven Bay (Spitzbergen )
Again Fairhaven
Greenland musk ox
Alpine cold desert at Hubbard Glacier in Alaska
Andean cold desert in the Andes between Mendoza ( ARG) and Santiago de Chile
Seamless transition from the hot Atacama desert in the cold desert of Llullaillaco volcano
In the National Park Torres del Paine in the extreme south of Chile
Cold desert on the Tibetan Plateau
At the foot of Mount Everest
Volcanic rocks on Palmer country in Antarctica
Ice edge on the Mather Island, Prydz Bay, Antarctica
The Bull Pass in the Transantarctic Mountains Olympus Range
Miers Valley in the McMurdo Dry Valleys of Antarctica