النطاق القطبي العتيق

النطاق القطبي العتيق

النطاق القطبي العتيق Palearctic أو Palaearctic هو أكبر ثمانية نطاقات جغرافية حيوية على وجه الأرض. ويمتد عبر كل أوراسيا شمال سفوح الهيمالايا و شمال أفريقيا.

The realm consists of several bioregions: the Euro-Siberian region; the Mediterranean Basin; the Sahara and Arabian Deserts; and Western, Central and East Asia. The Palaearctic realm also has numerous rivers and lakes, forming several freshwater ecoregions.

The term 'Palearctic' was first used in the 19th century, and is still in use as the basis for zoogeographic classification.

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التاريخ

In an 1858 paper for the Proceedings of the Linnean Society, British zoologist Philip Sclater first identified six terrestrial zoogeographic realms of the world: Palaearctic, Aethiopian/Afrotropic, Indian/Indomalayan, Australasian, Nearctic, and Neotropical. The six indicated general groupings of fauna, based on shared biogeography and large-scale geographic barriers to migration.[1]

Frontispiece to Alfred Russel Wallace's book The Geographical Distribution of Animals

Alfred Wallace adopted Sclater's scheme for his book The Geographical Distribution of Animals, published in 1876. This is the same scheme that persists today, with relatively minor revisions, and the addition of two more realms: Oceania and the Antarctic realm.


المناطق البيئية الرئيسية

The Palearctic realm includes mostly boreal/subarctic-climate and temperate-climate ecoregions, which run across Eurasia from western Europe to the Bering Sea.

Euro-Siberian region

The boreal and temperate Euro-Siberian region is the Palearctic's largest biogeographic region, which transitions from tundra in the northern reaches of Russia and Scandinavia to the vast taiga, the boreal coniferous forests which run across the continent. South of the taiga are a belt of temperate broadleaf and mixed forests and temperate coniferous forests. This vast Euro-Siberian region is characterized by many shared plant and animal species, and has many affinities with the temperate and boreal regions of the Nearctic realm of North America. Eurasia and North America were often connected by the Bering land bridge, and have very similar mammal and bird fauna, with many Eurasian species having moved into North America, and fewer North American species having moved into Eurasia. Many zoologists consider the Palearctic and Nearctic to be a single Holarctic realm. The Palearctic and Nearctic also share many plant species, which botanists call the Arcto-Tertiary Geoflora.

Mediterranean Basin

The lands bordering the Mediterranean Sea in southern Europe, north Africa, and western Asia are home to the Mediterranean Basin ecoregions, which together constitute the world's largest and most diverse mediterranean climate region of the world, with generally mild, rainy winters and hot, dry summers. The Mediterranean basin's mosaic of Mediterranean forests, woodlands, and scrub are home to 13,000 endemic species. The Mediterranean basin is also one of the world's most endangered biogeographic regions; only 4% of the region's original vegetation remains, and human activities, including overgrazing, deforestation, and conversion of lands for pasture, agriculture, and urbanization, have degraded much of the region. Formerly the region was mostly covered with forests and woodlands, but heavy human use has reduced much of the region to the sclerophyll shrublands known as chaparral, matorral, maquis, or garrigue. Conservation International has designated the Mediterranean basin as one of the world's biodiversity hotspots.

Sahara and Arabian deserts

A great belt of deserts, including the Atlantic coastal desert, Sahara desert, and Arabian desert, separates the Palearctic and Afrotropic ecoregions. This scheme includes these desert ecoregions in the palearctic realm; other biogeographers identify the realm boundary as the transition zone between the desert ecoregions and the Mediterranean basin ecoregions to the north, which places the deserts in the Afrotropic, while others place the boundary through the middle of the desert.

Western and Central Asia

The Caucasus mountains, which run between the Black Sea and the Caspian Sea, are a particularly rich mix of coniferous, broadleaf, and mixed forests, and include the temperate rain forests of the Euxine-Colchic deciduous forests ecoregion.

Central Asia and the Iranian plateau are home to dry steppe grasslands and desert basins, with montane forests, woodlands, and grasslands in the region's high mountains and plateaux. In southern Asia the boundary of the Palearctic is largely altitudinal. The middle altitude foothills of the Himalaya between about 2000–2500 m form the boundary between the Palearctic and Indomalaya ecoregions.

شرق آسيا

China, Korea and Japan are more humid and temperate than adjacent Siberia and Central Asia, and are home to rich temperate coniferous, broadleaf, and mixed forests, which are now mostly limited to mountainous areas, as the densely populated lowlands and river basins have been converted to intensive agricultural and urban use. East Asia was not much affected by glaciation in the ice ages, and retained 96 percent of Pliocene[بحاجة لمصدر] tree genera, while Europe retained only 27 percent. In the subtropical region of southern China and southern edge of the Himalayas, the Palearctic temperate forests transition to the subtropical and tropical forests of Indomalaya, creating a rich and diverse mix of plant and animal species. The mountains of southwest China are also designated as a biodiversity hotspot. In Southeastern Asia, high mountain ranges form tongues of Palearctic flora and fauna in northern Indochina and southern China. Isolated small outposts (sky islands) occur as far south as central Myanmar (on Nat Ma Taung, 3050 m), northernmost Vietnam (on Fan Si Pan, 3140 m) and the high mountains of Taiwan.

Freshwater

The realm contains several important freshwater ecoregions as well, including the heavily developed rivers of Europe, the rivers of Russia, which flow into the Arctic, Baltic, Black, and Caspian seas, Siberia's Lake Baikal, the oldest and deepest lake on the planet, and Japan's ancient Lake Biwa.

Flora and fauna

One bird family, the accentors (Prunellidae), is endemic to the Palearctic region. The Holarctic has four other endemic bird families: the divers or loons (Gaviidae), grouse (Tetraoninae), auks (Alcidae), and waxwings (Bombycillidae).

There are no endemic mammal orders in the region, but several families are endemic: Calomyscidae (mouse-like hamsters), Prolagidae, and Ailuridae (red pandas). Several mammal species originated in the Palearctic and spread to the Nearctic during the Ice Age, including the brown bear (Ursus arctos, known in North America as the grizzly), red deer (Cervus elaphus) in Europe and the closely related elk (Cervus canadensis) in far eastern Siberia, American bison (Bison bison), and reindeer (Rangifer tarandus, known in North America as the caribou).

Megafaunal extinctions

Several large Palearctic animals became extinct from the end of the Pleistocene into historic times, including Irish elk (Megaloceros giganteus), aurochs (Bos primigenius), woolly rhinoceros (Coelodonta antiquitatis), woolly mammoth (Mammuthus primigenius), North African elephant (Loxodonta africana pharaoensis), Chinese elephant (Elephas maximus rubridens), cave bear (Ursus spelaeus), Straight tusked elephant (Palaeoloxodon antiquus) and European lion (Panthera leo europaea).

المناطق البيئية البرية القطبية العتيقة

قالب:Palearctic tropical and subtropical moist broadleaf forest ecoregions

Palearctic temperate broadleaf and mixed forests
Apennine deciduous montane forests إيطاليا
Atlantic mixed forests Belgium، Denmark، France، Germany، Netherlands
Azores temperate mixed forests البرتغال
Balkan mixed forests Bosnia and Herzegovina، Bulgaria، Greece، Kosovo، North Macedonia، Romania، Serbia، Turkey
Baltic mixed forests Denmark، Germany، Poland، Sweden
Cantabrian mixed forests Portugal، Spain
Caspian Hyrcanian mixed forests Azerbaijan، Iran
Caucasus mixed forests Armenia، Azerbaijan، جورجيا، Russia، Turkey
Celtic broadleaf forests Ireland، United Kingdom
Central Anatolian deciduous forests تركيا
Central China loess plateau mixed forests China
Central European mixed forests Austria، Belarus، Czech Republic، Germany، Lithuania، Moldova، Poland
Central Korean deciduous forests North Korea، South Korea
Changbai Mountains mixed forests China، North Korea
Changjiang Plain evergreen forests China
Crimean Submediterranean forest complex Russia، Ukraine
Daba Mountains evergreen forests China
Dinaric Mountains mixed forests Albania، Bosnia and Herzegovina، Croatia، Italy، Montenegro، Serbia، Slovenia
East European forest steppe Bulgaria، Moldova، Romania، Russia، Ukraine
Eastern Anatolian deciduous forests Turkey
English Lowlands beech forests United Kingdom
Euxine–Colchic deciduous forests Bulgaria، Georgia، Turkey
Hokkaido deciduous forests Japan
Huang He Plain mixed forests China
Madeira evergreen forests Portugal
Manchurian mixed forests China، North Korea، Russia، South Korea
Nihonkai evergreen forests Japan
Nihonkai montane deciduous forests Japan
North Atlantic moist mixed forests Ireland، United Kingdom
Northeast China Plain deciduous forests China
Pannonian mixed forests Austria، Bosnia and Herzegovina، Croatia، Czech Republic، Hungary، Romania، Serbia، Slovakia، Slovenia، Ukraine
Po Basin mixed forests Italy
Pyrenees conifer and mixed forests Andorra، France، Spain
Qin Ling Mountains deciduous forests China
Rodope montane mixed forests Bulgaria، Greece، North Macedonia، Serbia
Sarmatic mixed forests Belarus، Denmark، Estonia، Finland، Latvia، Lithuania، Norway، Russia، Sweden
Sichuan Basin evergreen broadleaf forests China
South Sakhalin–Kurile mixed forests Russia
Southern Korea evergreen forests South Korea
Taiheiyo evergreen forests Japan
Taiheiyo montane deciduous forests Japan
Tarim Basin deciduous forests and steppe China
Ussuri broadleaf and mixed forests Russia
West Siberian broadleaf and mixed forests Russia
Western European broadleaf forests Austria، Czech Republic، France، Germany، Switzerland
Zagros Mountains forest steppe Iran، Iraq، Turkey

قالب:Palearctic temperate coniferous forest ecoregions قالب:Palearctic boreal forest/taiga ecoregions قالب:Palearctic temperate grassland, savanna, and shrubland ecoregions قالب:Palearctic flooded grassland and savanna ecoregions قالب:Palearctic montane grassland and shrubland ecoregions قالب:Palearctic tundra ecoregions قالب:Palearctic mediterranean forest, woodland, and scrub ecoregions

Palearctic deserts and xeric shrublands[2]
Afghan Mountains semi-desert Afghanistan
Alashan Plateau semi-desert الصين، منغوليا
الصحراء العربية مصر، إسرائيل، Iraq، Jordan، Kuwait، Palestine، Saudi Arabia، Yemen
Atlantic coastal desert Mauritania، Western Sahara
Azerbaijan shrub desert and steppe Azerbaijan، Georgia، Iran
Badghyz and Karabil semi-desert أفغانستان، Iran، Tajikistan، Turkmenistan، Uzbekistan
Baluchistan xeric woodlands Afghanistan، Pakistan
Caspian lowland desert Iran، Kazakhstan، Russia، Turkmenistan
Central Afghan Mountains xeric woodlands Afghanistan
Central Asian northern desert Kazakhstan، Uzbekistan
Central Asian riparian woodlands Kazakhstan، Turkmenistan، Uzbekistan
Central Asian southern desert Kazakhstan، Turkmenistan، Uzbekistan
Central Persian desert basins Afghanistan، Iran
Eastern Gobi desert steppe China، Mongolia
Gobi Lakes Valley desert steppe Mongolia
Great Lakes Basin desert steppe Mongolia، Russia
Junggar Basin semi-desert China، Mongolia
Kazakh semi-desert Kazakhstan
Kopet Dag semi-desert Iran، Turkmenistan
Mesopotamian shrub desert Iraq، Iran، Israel، Jordan، Syria
North Saharan steppe and woodlands Algeria، Egypt، Libya، Mauritania، Morocco، Tunisia، Western Sahara
Paropamisus xeric woodlands Afghanistan
Persian Gulf desert and semi-desert Bahrain، Kuwait، Oman، Qatar، Saudi Arabia، United Arab Emirates
Qaidam Basin semi-desert China
Red Sea coastal desert Egypt، Sudan
Red Sea Nubo–Sindian tropical desert and semi-desert Egypt، Jordan، Oman، Saudi Arabia، Yemen
Registan–North Pakistan sandy desert Afghanistan، Iran، Pakistan
Sahara desert Algeria، Chad، Egypt، Libya، Mali، Niger، Sudan، Western Sahara
South Iran Nubo–Sindian desert and semi-desert Iran، Iraq، Pakistan
South Saharan steppe and woodlands Algeria، Chad، Mali، Mauritania، Niger، Sudan
Taklimakan desert China
Tibesti–Jebel Uweinat montane xeric woodlands Chad، Egypt، Libya، Sudan
West Saharan montane xeric woodlands Algeria، Mali، Mauritania، Niger


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المراجع

  1. ^ Sclater, Philip Lutley (1858). "On the general geographical distribution of the members of the class Aves". Zoological Journal of the Linnean Society. 2 (7): 130–145. doi:10.1111/j.1096-3642.1858.tb02549.x.
  2. ^ Eric Dinerstein, David Olson, et al. (2017). An Ecoregion-Based Approach to Protecting Half the Terrestrial Realm, BioScience, Volume 67, Issue 6, June 2017, Pages 534–545 [1]

المراجع العامة

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