Floristic Regions of the World, Biology tutorial

General Description of the Holarctic Kingdom:

Boreal Kingdom or Holarctic Kingdom (Holarctic) is the floristic kingdom recognized by botanist Ronald Good (and later by Armen Takhtajan), that comprises temperate to Arctic portions of North America and Eurasia. Its flora is inherited from ancient supercontinent of Laurasia. Though, much of floristic kingdom (and most of its Circumboreal Region) was glaciated during Pleistocene and has very young flora.

Millions of years ago, before opening of Atlantic Ocean, North America and Eurasia were joined as single continent, Laurasia. After opening of Atlantic, continents were connected to one another occasionally via land bridges linking Alaska and Siberia. Until few million years ago, global climate was warmer than at present, particularly at higher latitudes, and several temperate climate species were dispersed across North America and Eurasia via Alaska and Siberia.

Sharply cooler climate of past few million years eliminated the temperate-zone connection between North America and Eurasia, but common Laurasian origins and long history of temperate-climate land bridges account for botanical similarities between temperate floras on two continents.

Subdivisions of the Holarctic Kingdom:

Boreal Subkingdom: Circumboreal Region, North American Atlantic Region, Eastern Asiatic Region, Rocky Mountain Region. Macaronesian Region.

Tethyan Subkingdom: Mediterranean Region, Saharo-Arabian Region, Irano-Turanian Region.

Madrean Subkingdom: Madrean Region.

The Circumboreal Region:

The Circumboreal Region is floristic region within Holarctic Kingdom in Eurasia and North America, as delineated by such geobotanists as Josias Braun-Blanquet and Armen Takhtajan. It is the largest floristic region in world by area, including most of Alaska, Canada, Europe, Caucasus and Russia, and North Anatolia (as southernmost part of region) and parts of northern New England, Michigan, and Minnesota.

Floristic Provinces: It is subdivided in number of floristic provinces. Their delineation is debatable. According to the version of Takhtajan's classification, these are Atlantic European, Arctic, Central European, Caucasian, Illyrian, Eastern European, Northern European, Euxinian, West Siberian.

Arctic Province (Greenland, Iceland, northern treeless parts of Norway, Russia, Finland, Alaska and Canada, all Arctic Islands), with one endemic genus (Diapensia) and more than hundred endemic species (e.g. Ranunculus sabinei, Papaver polare, Salix arctica, Colpodium vahlianum, olpodium wrightii, Puccinellia angustata).

Atlantic European Province (Ireland, United Kingdom, Andorra, parts of Portugal, Spain, France, Belgium, Netherlands, Germany, Denmark and Norway), with two endemic genera (Petrocoptis and Thorella), few dozens of endemic species (e.g. Corydalis claviculata, Ulex europaeus, Deschampsia setacea).

Tethyan Subkingdom: This is divided into the macronesia region, the Mediterranean region

Macaronesia Region:

Macaronesia is a modern collective name for several groups of islands in the North Atlantic Ocean near Europe and North Africa belonging to three countries: Portugal, Spain, and Cape Verde. The name (which is often misspelt 'Macronesia') comes from the Greek for "islands of the fortunate". Macaronesia consists of five archipelagos:

Azores (Portugal)

Canary Islands (Spain)

Cape Verde (Cape Verde)

Madeira, including Porto Santo Island and the Desertas Islands (Portugal)

Savage Islands (Portugal), administratively part of the Madeira Autonomous Region.

The islands of Macaronesia are volcanic in origin, and are supposed to be product of many geologic hotspots. Climate of Macaronesian islands ranges from subtropical to tropical. None of the Macaronesian islands were part of continent, so native plants and animals reached islands through long-distance dispersal. Laurel-leaved forests, known as laurisilva, once covered most of Azores, Madeira, and parts of the Canaries between 400-1200 m altitude (the eastern Canaries and Cape Verde being too dry).

Mediterranean Basin: Mediterranean Basin includes lands around and enclosed by Mediterranean Sea. In biogeography, Mediterranean Basin refers to lands around Mediterranean Sea which have Mediterranean climate, with mild, rainy winters and hot, dry summers, that supports characteristic Mediterranean forests, woodlands, and scrub vegetation.

Geography: The Mediterranean basin covers portions of 3 continents, Europe, Asia, and Africa. Europe lies to north, and three large Southern European peninsulas, Iberian Peninsula, Italian Peninsula, and Balkan Peninsula, extend in Mediterranean-climate zone. The system of folded mountains, comprising Pyrenees dividing Spain from France, Alps dividing Italy from Central Europe, Dinaric Alps along the eastern Adriatic, and the Balkan and Rhodope Mountains of the Balkan Peninsula divide the Mediterranean from the temperate climate regions of Western and Central Europe.

General explanation of Paleotropical Kingdom:

Paleotropical Kingdom (Paleotropis) is the floristic kingdom including tropical areas of Africa, Asia and Oceania (without Australia). Its flora is characterized by approx 40 endemic plant families, like Nepenthaceae, Musaceae, Pandanaceae, Flagellariaceae. Part of its flora, inherited from ancient supercontinent of Gondwana or exchanged later (like Piperaceae with pantropical distribution and but few warm temperate representatives), is shared with Neotropical Kingdom, including tropical areas of Central and South America. Furthermore, Paleotropical flora influenced tropical flora of Australian Kingdom.

The Subkingdoms of Paleotropical Kingdom:

Paleotropical Kingdom is subdivided in 5 floristic subkingdoms about 13 floristic regions. Floristic subkingdoms of paleotropical kingdom are as follows: African Subkingdom, Polynesian Subkingdom, Madagascan Subkingdom, Indo-Malesian Subkingdom and Neocaledonian Subkingdom

a) African Subkingdom: This has 10 endemic families and many endemic genera. 10 endemic families comprise Pentadiplandraceae, Dioncophyllaceae, Scytopetalaceae etc. Subkingdom is composed of Guineo-Congolian Province, Usambara-Zululand Region and Sudano-Zambezian Region.

b) Madagascan Subkingdom: This has 9 endemic families, over 450 endemic genera, and approx 80% endemic species. It ceased to be influenced by African flora in Cretaceous, but underwent heavy influence of Indian Region's flora.

c) Indo-Malesian Subkingdom: This has 11 endemic families (comprising Degeneriaceae, Barclayaceae, Mastixiaceae) and several endemic genera. It is made Indian Region, Indochinese Region, Malesian Region and Fijian Region.

d) Polynesian Subkingdom: This subkingdom has no endemic families and several endemic genera. Flora is generally derivative from that of Indo-Malesian Subkingdom. It has Polynesian Region and Hawaiian Region.

e) Neocaledonian Subkingdom: This has many endemic families (comprising Amborellaceae, Strasburgeriaceae) and over 130 endemic genera (comprising. Exospermum and Zygogynum). Flora is partly shared with Indo-Malesian Subkingdom and Australian Kingdom. It has Neocaledonian Region.

Neotropical Kingdom:

General Description of the Neotropical Kingdom:

In biogeography, Neotropic or Neotropical zone is one of the eight terrestrial ecozones. This ecozone comprises South and Central America, the Mexican lowlands, Caribbean islands, and southern Florida, as these regions share large number of plant and animal groups. It is at times utilized as synonym for tropical area of South America, though ecozone also comprises temperate southern South America. Neotropical Floristic Kingdom excludes southernmost South America that instead is placed in Antarctic Kingdom. Neotropic comprises more tropical rainforest (tropical and subtropical moist broadleaf forests) than any other ecozone, extending from southern Mexico through Central America and northern South America to southern Brazil, comprising vast Amazon Rainforest.

Major Ecological Regions of Neotropic Kingdom:

The WWF subdivides ecozone in bioregions, stated as geographic clusters of ecoregions which may span many habitat types, but have strong biogeographic affinities, mainly at taxonomic levels higher than species level (genus, family)."

a) Amazonia Region: Amazonia bioregion is generally covered by tropical moist broadleaf forest, comprising vast Amazon rainforest that stretches from Andes Mountains to Atlantic Ocean, and lowland forests of Guianas. The bioregion also comprises tropical savannah and tropical dry forest ecoregions.

b) Eastern South America Region: Eastern South America comprises Caatinga xeric shrublands of northeastern Brazil, broad Cerrado grasslands and savannas of Brazilian Plateau, and Pantanal and Chaco grasslands.

c) Orinoco Region: Orinoco is the region of humid forested broadleaf forest and wetland mainly including drainage basin for Orinoco River and other adjacent lowland forested areas.

d) Southern South America Region: Temperate forest ecoregions of southwestern South America, comprising temperate rain forests of Valdivian temperate rain forests and Magellanic subpolar forests ecoregions, and Juan Fernandez Islands and Desventuradas Islands, are refuge for the ancient Antarctic flora, which includes trees like the southern beech (Nothofagus), podocarps, the alerce (Fitzroya cupressoides).

Endemic Animals and Plants in Neotropical Kingdom:

Animals: Thirty-one bird families are endemic to Neotropical ecozone, over twice number of any other ecozone. They comprise rheas, tinamous, curassows, and toucans. Bird families initially unique to Neotropics comprise hummingbirds (family Trochilidae) and wrens (family Troglodytidae).

Mammal groups initially unique to Neotropics include:

Order Xenarthra: anteaters, sloths, and armadillos New World monkeys, Caviomorpha rodents, comprising capybaras and guinea pigs, and chinchillas American opossums (order Didelphimorphia) and shrew opossums (order Paucituberculata). Some fish groups initially unique to Neotropics include:

Order Gymnotiformes Neotropical electric fish

Family Characidae tetras and allies

Family Loricariidae armoured catfishes

Subfamily Cichlinae Neotropical cichlids

Subfamily Poeciliinae guppies and relatives.

Examples of groups which are completely or primarily limited to Neotropical region comprise New World Monkeys, Sloths, Tinamous, Hummingbirds, Toucans, and Ovenbirds.

Plants: Plant families which originated in Neotropic comprise Bromeliaceae, Cannaceae, and Heliconiaceae. Plant species initially unique to Neotropic comprise: Potato (Solanum tuberosum), Tomato (Solanum lycopersicum), source of cocoa and chocolate, Maize (Zea mays), Lima bean (Phaseolus lunatus), Cacao tree (Theobroma cacao), Cotton (Gossypium barbadense), Sweet potato (Ipomoea batatas), Cassava (Manihot esculenta), Amaranth (Amaranthus caudatus), Quinoa (Chenopodium quinoa).

General Description of the South African Kingdom:

The Cape Floristic Region is the floristic region situated near southern tip of South Africa. It is the only floristic region of Cape (South African) Floristic Kingdom, and comprises only one floristic province, called as Cape Floristic Province. Cape Floristic Region, the smallest of six identified floral kingdoms of the world, is the area of extremely high diversity and endemism, and is home to more than 9000 vascular plant species, of which 69 % are endemic. Much of this diversity is related with fynbos biome, a Mediterranean-type, fire-prone shrub land. Economic worth of fynbos biodiversity based on harvests of fynbos products (like wildflowers) and eco-tourism is evaluated to be in region of R77 million a year. Therefore, it is clear that Cape Floristic Region has both economic and intrinsic biological value as biodiversity hotspot.

Location and Description:

The Region covers Mediterranean climate region of South Africa in Western Cape in southwestern corner of country, and extends eastward in Eastern Cape, a transitional zone between winter rainfall region to west and summer-rainfall region to east in KwaZulu-Natal.

Flora: Fynbos in Western Cape

Most of the region is covered with fynbos, a sclerophyllous shrubland happening on acid sands or nutrient poor soils derived from Table Mountain Sandstones (Cape Supergroup). Fynbos is home to the amazing diversity of plant species comprising several members of Protea family (Proteaceae), Heath family (Ericaceae), and Reed family of restios (Restionaceae). Other vegetation kinds are strandveld, a soft coastal scrubland found mostly on west-facing coast of Western Cape Province, on tertiary sands.

Ecology:

World Wildlife Fund separates Cape floristic region in three ecoregions, Lowland fynbos and renosterveld, Montane fynbos and renosterveld and Albany thickets. Fynbos eco-regions are designated one of the Global 200 priority ecoregions for conservation. Conservation International declared Cape floristic region to be the biodiversity hotspot.

General Description of Antarctic Kingdom:

Antarctic Floristic Kingdom (also Holantarctic Kingdom) is the floristic region first recognized by botanist Ronald Good (and later by Armen Takhtajan) that comprises most areas of world south of 40°S latitude. Antarctic plant kingdom comprises continent of Antarctica, Patagonia (southern Chile, southern Argentina, Tierra del Fuego), most of New Zealand, New Zealand Sub-Antarctic Islands, and all islands of Southern Ocean south of 40°S latitude, comprising Gough Island, Kerguelen Islands, and Falkland Islands.

Tasmania is omitted as its plant species are more strongly associated to those found in Australian Floristic Kingdom. Several plant species of Antarctica, temperate South America and New Zealand were extremely strongly related, despite their disjunction by vast Southern Ocean. Flora of this kingdom dates back to time of Gondwana, southern supercontinent that once incorporated most of the landmasses of present-day Southern Hemisphere, although it has been influenced by flora of Holarctic Kingdom as the Tertiary. Approx 50 genera of vascular plants are common in Antarctic plant kingdom, comprising Nothofagus and Dicksonia. There are approx 11 families of plants which are endemic to this kingdom: Lactoridaceae, Gomortegaceae, Hectorellaceae, Halophytaceae, Francoaceae, Aextoxicaceae etc.

Subdivisions:

Antarctic floristic kingdom is subdivided in 4 floristic regions, and subdivided even further in 16 floristic provinces. Most of the provinces lie inside, or very near Antarctic convergence zone.

1) Fernandezian Region:

This is frequently included inside Neotropical Kingdom. It has Endemic family: Lactoridaceae. There are 20 endemic genera comprising Juania, Thyrsopteris, Selkirkia, Nothomyrcia, Cuminia, Symphyochaeta, Robinsonia, Rhetinodendron, Centaurodendron, and Megalachne. Species endemism of vascular plants is extremely high (about 70%). It is composed of Fernandezian Province.

2) Argentina-Chile-Patagonian Region:

This has the following endemic families: Gomortegaceae, Halophytaceae, Malesherbiaceae, Tribelaceae, Francoaceae, Aextoxicaceae, and Misodendraceae. There are many endemic genera (including Leptocionium, Saxegothaea, Austrocedrus, Pilgerodendron, Fitzroya, Peumus, Boquila, Lardizabala, Philippiella, Austrocactus, etc. It is composed of Northern Chilean Province, Central Chilean Province, Argentine Pampas Province, Patagonian Province and Tierra del Fuego Province.

3) Neozeylandic Region:

This has the endemic family: Ixerbaceae that is endemic monogeneric family of one species, Ixerba brexioides. The Ixerbaceae is only endemic New Zealand vascular plant family. There are 50 endemic genera in region (comprising Loxsoma, Pseudowintera, Hectorella, Entelea, Hoheria, Corokia, Alseuosmia, Carmichaelia, Lophomyrtus etc. Provinces in region comprise Lord Howe Province, Norfolkian Province, the Southern Neozeylandic Province, the Chatham Province and the New Zealand Subantarctic Islands Province.

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