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27-455: Palearctic Nearctic Afrotropical Australasian Indomalayan Oceanian but also in the genera Erythrotriorchis , Megatriorchis , Melierax , and Micronisus : Afrotropical Australasian Palearctic The Palearctic or Palaearctic is the largest of the eight biogeographic realms of the Earth. It stretches across all of Eurasia north of

54-477: 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 , 3,050 m; 10,010 ft), northernmost Vietnam (on Fan Si Pan , 3,140 m; 10,300 ft) and the high mountains of Taiwan . The realm contains several important freshwater ecoregions as well, including

81-571: A large role in shaping the ecology of Mediterranean ecoregions . The hot, dry summers make much of the region prone to fires, and lightning-caused fires occur with some frequency. Many of the plants are pyrophytes , or fire-loving, adapted or even depending on fire for reproduction, recycling of nutrients, and the removal of dead or senescent vegetation. In both the Australian and Californian Mediterranean-climate eco-regions, native peoples used fire extensively to clear brush and trees, making way for

108-730: A native shrubland to non-native annual grassland and drastically reduce species diversity, especially under drought brought about by climate change . On 25 July 2023, devastating wildfires were burning in at least nine countries across the Mediterranean, including Croatia , Italy , and Portugal , with thousands of firefighters in Europe and North Africa working to contain flames stoked by high temperatures, dry conditions, and strong winds. The wildfires led to casualties, evacuations of thousands of people, and widespread destruction of homes and forests. Mediterranean ecoregions are some of

135-512: Is a biome defined by the World Wide Fund for Nature . The biome is generally characterized by dry summers and rainy winters, although in some areas rainfall may be uniform. Summers are typically hot in low-lying inland locations but can be cool near colder seas. Winters are typically mild to cool in low-lying locations but can be cold in inland and higher locations. All these ecoregions are highly distinctive, collectively harboring 10% of

162-405: 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

189-546: Is equivalent to about 40% of the plant species of the United States and Canada combined, found within an area the size of the state of Maine . The fynbos and Southwest Australia shrublands have flora that are significantly more diverse than the other ecoregions, although any Mediterranean shrubland is still rich in species and endemics relative to other non-forest ecoregions. Major plant communities in this biome include: Fire, both natural and human-caused, has played

216-624: Is the same scheme that persists today, with relatively minor revisions, and the addition of two more realms: Oceania and the Antarctic realm . The Palearctic realm includes mostly boreal/subarctic-climate and temperate-climate ecoregions, which run across Eurasia from western Europe to the Bering Sea . The boreal and temperate Euro-Siberian region is the Palearctic's largest biogeographic region, which transitions from tundra in

243-464: The Balkans (including Northern Greece ), as well as Northern and Western Jordan . Vegetation types range from forests to woodlands , savannas , shrublands , and grasslands ; " mosaic habitat " landscapes are common, where differing vegetation types are interleaved with one another in complex patterns created by variations in soil, topography, exposure to wind and sun, and fire history. Much of

270-539: 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 . The lands bordering

297-570: 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

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324-698: The caribou ). 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 ). Mediterranean forests, woodlands, and scrub Mediterranean forests, woodlands and scrub

351-468: 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 . 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

378-628: 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 2,000–2,500 m (6,600–8,200 ft) form

405-498: The Earth's plant species. The Mediterranean forests, woodlands, and scrub biome mostly occurs in, but not limited to, the Mediterranean climate zones, in the mid-latitudes: The biome is not limited to the Mediterranean climate zone. It can also be present in other climate zones (which typically border the Mediterranean climate zone), such as the drier regions of the oceanic and humid subtropical climates , and as well as

432-698: The basis for zoogeographic classification. 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. Alfred Wallace adopted Sclater's scheme for his book The Geographical Distribution of Animals , published in 1876. This

459-412: The boundary between the Palearctic and Indomalaya ecoregions. 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

486-525: The foothills of the Himalayas , and North Africa . The realm consists of several bioregions : the Euro-Siberian region; the Mediterranean Basin ; North Africa ; North Arabia ; 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

513-884: The grasses and herbaceous vegetation that supported game animals and useful plants. The plant communities in these areas adapted to the frequent human-caused fires, and pyrophyte species grew more common and more fire-loving, while plants that were poorly adapted to fire retreated. After European colonization of these regions, fires were suppressed, which has caused some unintended consequences in these ecoregions; fuel builds up, so that when fires do come they are much more devastating, and some species dependent on fire for their reproduction are now threatened. The European shrublands have also been shaped by anthropogenic fire, historically associated with transhumance herding of sheep and goats. Though adapted to infrequent fires, chaparral plant communities can be eliminated by frequent fires. A high frequency of fire (less than ten years) will result in

540-580: 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 . 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

567-431: The loss of obligate seeding shrub species such as Manzanita spp. This high frequency disallows seeder plants to reach their reproductive size before the next fire and the community shifts to a sprouter-dominance. If high frequency fires continue over time, obligate resprouting shrub species can also be eliminated by exhausting their energy reserves below-ground. Today, frequent accidental ignitions can convert chaparral from

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594-773: The lusher areas of the semi-arid climate zone. Non-Mediterranean climate regions that would feature Mediterranean vegetation include the Nile River Valley in Egypt (extending upstream along the riverbanks), parts of the Eastern Cape in South Africa, southeastern Australia, southeastern Azerbaijan , southeastern Turkey, far northern Iraq , the Mazandaran Province in Iran , Central Italy , parts of

621-542: 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

648-630: 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. 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

675-752: 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

702-642: The woody vegetation in Mediterranean-climate regions is sclerophyll, which means 'hard-leaved' in Greek. Sclerophyllous vegetation generally has small, dark leaves covered with a waxy outer layer to retain moisture in the dry summer months. Phytogeographers consider the fynbos (South Africa) as a separate floral kingdom because 68% of the 8,600 vascular plant species crowded into its 90,000 square kilometers (35,000 sq mi) are endemic and highly distinctive at several taxonomic levels. This

729-502: 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 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

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