Phytochorion
A phytochorion, in phytogeography, is a geographic area with a relatively uniform composition of plant species. Adjacent phytochoria do not usually have a sharp boundary, but rather a soft one, a transitional area in which many species from both regions overlap. The region of overlap is called a vegetation tension zone.
In some schemes, areas of phytochoria are classified hierarchically, e.g., in Floral (or Floristic, Phytogeographic) Kingdoms, Regions and Provinces, sometimes including the categories Empire and Domain, while others prefer not to rank areas, referring to them simply as "regions" or "phytochoria".[1]
The systems used to classify vegetation can be divided in two major groups: those that use physiognomic-environmental parameters and characteristics and those that are based on floristic relationships.[2] Phytochoria are defined by their plant taxonomic composition, while other schemes of regionalization (e.g., phytophysiognomies, formations, biomes) may variably take in account, according to the author, the apparent characteristics of a community (the dominat life-form), environment characteristics, the fauna associated, anthropic factors or political-conservationist issues.[3]
Explanation
Several systems of classifying geographic areas where plants grow have been devised. Most systems are organized hierarchically, with the largest units subdivided into smaller geographic areas, which are made up of smaller floristic communities, and so on. Phytochoria are defined as areas possessing a large number of endemic taxons. Floristic kingdoms are characterized by a high degree of family endemism, floristic regions by a high degree of generic endemism, and floristic provinces by a high degree of species endemism. Systems of phytochoria have both significant similarities and differences with zoogeographic provinces, which follow the composition of mammal families, and with biogeographical provinces or terrestrial ecoregions, which take into account both plant and animal species.
The term phytochorion is especially associated with the classifications according to the methodology of Josias Braun-Blanquet, which is tied to the presence or absence of particular species.[4]
Taxonomic databases tend to be organized in ways which approximate floristic provinces, but which are more closely aligned to political boundaries, for example according to the World Geographical Scheme for Recording Plant Distributions.
Good's floristic regionalization
Botanist Ronald Good identified six floristic kingdoms (Boreal or Holarctic, Neotropical, Paleotropical, South African, Australian, and Antarctic), the largest natural units he determined for flowering plants. Good's six kingdoms are subdivided into smaller units, called provinces. The Paleotropical kingdom is divided into three subkingdoms, which are each subdivided into floristic provinces. Each of the other five kingdoms are subdivided directly into provinces. There are a total of 37 floristic provinces. Almost all provinces are further subdivided into floristic regions.
Takhtajan's floristic regionalization
Armen Takhtajan, in a widely used scheme that builds on Good's work, identified thirty-five floristic regions, each of which is subdivided into floristic provinces, of which there are 152 in all.
.png)
- 1 Arctic
- 2 Atlantic Europe
- 3 Central Europe
- 4 Illyria or Balkan
- 5 Pontus Euxinus
- 6 Caucasus
- 7 Eastern Europe
- 8 Northern Europe
- 9 Western Siberia
- 10 Altai-Sayan
- 11 Central Siberia
- 12 Transbaikalia
- 13 Northeastern Siberia
- 14 Okhotsk-Kamchatka
- 15 Canada incl. Great Lakes
- 16 Manchuria
- 17 Sakhalin-Hokkaidō
- 18 Japan-Korea
- 19 Volcano-Bonin
- 20 Ryūkyū or Tokara-Okinawa
- 21 Taiwan
- 22 Northern China
- 23 Central China
- 24 Southeastern China
- 25 Sikang-Yuennan
- 26 Northern Burma
- 27 Eastern Himalaya
- 28 Khasi-Manipur
- 29 Appalachian Province (forested areas extending east to include the piedmont and west to the start of the prairies)
- 30 Atlantic and Gulf Coastal Plain
- 31 North American Prairies
- 32 Vancouver
- 33 Rocky Mountains
- 34 Azores
- 35 Madeira
- 36 Canaries
- 37 Cape Verde
- 38 Southern Morocco
- 39 Southwestern Mediterranean
- 40 South Mediterranean
- 41 Iberia
- 42 Baleares
- 43 Liguria-Tyrrhenia
- 44 Adriatic
- 45 East Mediterranean
- 46 Crimea-Novorossijsk
VIII. Irano-Turanian Region
- 49 Mesopotamia
- 50 Central Anatolia
- 51 Armenia-Iran
- 52 Hyrcania
- 53 Turania or Aralo-Caspia
- 54 Turkestan
- 55 Northern Baluchistan
- 56 Western Himalaya
- 57 Central Tien Shan
- 58 Dzungaria-Tien Shan
- 59 Mongolia
- 60 Tibet
IX. Madrean Region
- 61 Great Basin
- 62 Californian
- 63 Sonoran
- 64 Mexican Highlands
X. Guineo-Congolian Region
- 65 Upper Guinean forests
- 66 Nigeria-Cameroon
- 67 Congo
XI. Usambara-Zululand Region
- 68 Zanzibar-Inhambane
- 69 Tongoland-Pondoland
XII. Sudano-Zambezian Region
- 70 Zambezi
- 71 Sahel
- 72 Sudan
- 73 Somalia-Ethiopia
- 74 South Arabia
- 75 Socotra
- 76 Oman
- 77 South Iran
- 78 Sindia
XIII. Karoo-Namib Region
- 79 Namibia
- 80 Namaland
- 81 Western Cape
- 82 Karoo
XIV. St.Helena and Ascension Region
- 83 St. Helena and Ascension
- 84 Eastern Madagascar
- 85 Western Madagascar
- 86 Southern and Southwestern Madagascar
- 87 Comoro
- 88 Mascarenes
- 89 Seychelles
XVI. Indian Region
- 90 Ceylon (Sri Lanka)
- 91 Malabar
- 92 Deccan
- 93 Upper Gangetic Plain
- 94 Bengal
XVII. Indochinese Region
- 95 South Burma
- 96 Andamans
- 97 South China
- 98 Thailand
- 99 North Indochina
- 100 Annam
- 101 South Indochina
XVIII. Malesian Region
- 102 Malaya
- 103 Borneo
- 104 Philippines
- 105 Sumatra
- 106 South Malesia
- 107 Celebes
- 108 Moluccas and West New Guinea
- 109 Papua
- 110 Bismarck Archipelago
XIX. Fijian Region
- 111 New Hebrides
- 112 Fiji
XX. Polynesian Region
- 113 Micronesia
- 114 Polynesia
XXI. Hawaiian Region
- 115 Hawaii
XXII. Neocaledonian Region
- 116 New Caledonia
XXIII. Caribbean Region
- 117 Central America
- 118 West Indies
- 119 Galápagos Islands
XXIV. Region of the Guayana Highlands
- 120 The Guianas
XXV. Amazonian Region
XXVI. Brazilian Region
- 123 Caatinga
- 124 Central Brazilian Uplands
- 125 Chaco
- 126 Atlantic Brazil
- 127 Parana
XXVII. Andean Region
- 128 Northern Andes
- 129 Central Andes
XXVIII. Cape Region
- 130 Cape Province
Australian Kingdom
XXIX. Northeast Australian Region
- 131 North Australia
- 132 Queensland
- 133 Southeast Australia
- 134 Tasmania
XXX. Southwest Australian Region
XXXI. Central Australian or Eremaean Region
- 136 Eremaea
XXXII. Fernandezian Region
- 137 Juan Fernández
XXXIII. Chile-Patagonian Region
- 138 Northern Chile
- 139 Central Chile
- 140 Pampas
- 141 Patagonia
- 142 Tierra del Fuego
XXXIV. Region of the South Subantarctic Islands
XXXV. Neozeylandic Region
- 145 Lord Howe
- 146 Norfolk
- 147 Kermadec
- 148 Northern New Zealand
- 149 Central New Zealand
- 150 Southern New Zealand
- 151 Chatham
- 152 New Zealand Subantarctic Islands
References
- ^ Linder, Lovett, Mutke, et al. (2005): A numerical re-evaluation of the sub-Saharan phytochoria. Biologiske Skrifter 55: 229-252.
- ^ JOLY, C.A., AIDAR, M.P.M., KLINK, C.A., McGRATH, D.G., MOREIRA, A.G., MOUTINHO, P., NEPSTAD, D.C., OLIVEIRA, A.A.; POTT, A.; RODAL, M.J.N. & SAMPAIO, E.V.S.B. 1999. Evolution of the Brazilian phytogeography classification systems: implications for biodiversity conservation. Ci. e Cult. 51: 331-348.
- ^ http://www.scielo.br/pdf/abb/v20n1/02.pdf
- ^ glossary from Edited by A. Barrie Low and A. (Tony) G. Rebelo from contributions by George J. Bredenkamp, J. Ed Granger, M. Timm Hoffman, Roy A. Lubke, Bruce Mckenzie, A. (Tony) Rebelo, & Noel van Rooyen (February 1998). Vegetation of South Africa, Lesotho and Swaziland: A companion to the Vegetation Map of South Africa, Lesotho and Swaziland. Department of Environmental Affairs and Tourism, Pretoria.
{{cite book}}:|author=has generic name (help)CS1 maint: multiple names: authors list (link)
- Cox, C. B. (2001). The biogeographic regions reconsidered. Journal of Biogeography, 28(4): 511-523.
- Good, Ronald (1947). The Geography of Flowering Plants. Longmans, Green and Co, New York
- Nelson, G.J. (1978). From Candolle to Croizat: Comments on the history of biogeography. Journal of the History of Biology, 11: 269–305.
- Takhtajan, Armen (1986). Floristic Regions of the World. (translated by T.J. Crovello & A. Cronquist). University of California Press, Berkeley.
- Udvardy, M. D. F. (1975). A classification of the biogeographical provinces of the world. IUCN Occasional Paper no. 18. Morges, Switzerland: IUCN. [1]