The Palearctic or Palaearctic is one of the eight
ecozones dividing the Earth surface.
Physically, the Palearctic is the largest ecozone. It includes the
terrestrial ecoregions of Europe, Asia north of the Himalayafoothills, northern Africa, and the northern and central parts of the Arabian Peninsula.
Major ecological regions
The Palearctic ecozone includes mostly boreal and
temperateclimate ecoregions, which run across Eurasiafrom western Europe to the Bering Sea.
The boreal and temperate European-Siberian region is the Palearctic's largest biogeographic region, which transitions from
tundrain the northern reaches of Russiaand Scandinaviato the vast taiga, the boreal coniferous forests which run across the continent. South of the taiga are a belt of temperate broadleaf and mixed forestsand temperate coniferous forests. This vast European-Siberian region is characterized by many shared plant and animal species, and has many affinities with the temperate and boreal regions of the Nearcticecoregion of North America. Eurasia and North America were often connected by the Bering land bridge, and have very similar mammaland 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 Holarcticecozone. The Palearctic and Nearctic also share many plant species, which botanists call the Arcto-Tertiary Geoflora.
The lands bordering the
Mediterranean Seain southern Europe, north Africa, and western Asia are home to the Mediterranean basinecoregions, which together constitute world's largest and most diverse mediterranean climateregion of the world, with generally mild, rainy winters and hot, dry summers. The Mediterranean basin's mosaic of Mediterranean forests, woodlands, and shrubare 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, or 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 sclerophyllshrublands known as chaparral, matorral, maquis, or garrigue. Conservation Internationalhas designated the Mediterranean basin as one of the world's biodiversity hotspots.
ahara and Arabian deserts
A great belt of deserts, including the
Atlantic coastal desert, Sahara desert, and Arabian desert, separates the Palearctic and Afrotropicecoregions. This scheme includes these desert ecoregions in the palearctic ecozone; other biogeographers identify the ecozone 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
Caucasusmountains, which run between the Black Seaand 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 forestsecoregion. Central Asiaand the Iranian plateauare home to dry steppe grasslandsand desertbasins, 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 Himalayabetween about 2000-2500 m form the boundary between the Palearctic and Indomalayaecoregions.
China and Japan
Chinaand Japanare 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 tree genera, while Europe retained only 27 percent. In the subtropical southern parts of China and Japan, 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 Chinaare also designated as a biodiversity hotspot. In Southeastern Asia, high mountain ranges form tongues of Palearctic flora and fauna in northern Myanmarand southern China. Isolated small outposts ( sky islands) occur as far south as central Myanmar (on Mt. Victoria, 3050 m), northernmost Vietnam(on Fan Si Pan, 3140 m) and the high mountains of Taiwan.
The ecozone 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
mammalorders 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 ages, 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).
Palearctic terrestrial ecoregions
Amorosi, T. "Contributions to the zooarchaeology of Iceland: some preliminary notes." in 'The Anthropology of Iceland' (eds. E.P. Durrenberger & G. Pálsson). Iowa City: University of Iowa Press, pp. 203-227, 1989.
Buckland, P.C., et al. "Holt in Eyjafjasveit, Iceland: a paleoecological study of the impact of Landnám." in 'Acta Archaeologica' 61: pp. 252-271. 1991.
* [http://www.panda.org/about_wwf/where_we_work/ecoregions/maps/index.cfm Map of the ecozones]
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