View source for Biogeographic realm

{{Short description|Broadest biogeographic division of Earth's land surface}}
{{Use shortened footnotes|date=May 2021}}  

[[File:Ecozones.svg|thumb|upright=2|Map of the world's biogeographic realms in [[Miklos Udvardy]]'s system.
{{div col|colwidth=12em}}
{{legend|#a6b866|[[Nearctic realm|Nearctic]] }}
{{legend|#b75a5a|[[Palearctic realm|Palearctic]]}}
{{legend|#7188a5|[[Afrotropical realm|Afrotropical]]}}
{{legend|#c09551|[[Indomalayan realm|Indomalayan]]}}
{{legend|#d78637|[[Australasian realm|Australasian]] }}
{{legend|#a18fa4|[[Neotropical realm|Neotropical]]}}
{{legend|#808080|[[Oceanian realm|Oceanian]]}}
{{legend|#f9f9f9|[[Antarctic realm|Antarctic]] (not shown)}}
{{div col end}}]]

A '''biogeographic realm''' is the broadest [[biogeography|biogeographic]] division of Earth's land surface, based on distributional patterns of [[terrestrial animal|terrestrial]] organisms. They are subdivided into [[bioregion]]s, which are further subdivided into [[ecoregion]]s.
A biogeographic realm is also known as "ecozone", although that term may also refer to ecoregions.

==Description==
The realms delineate large areas of Earth's surface within which organisms have evolved in relative isolation over long periods of time, separated by geographic features, such as [[ocean]]s, broad [[desert]]s, or high [[mountain range]]s, that constitute [[natural barrier]]s to migration.  As such, biogeographic realm designations are used to indicate general groupings of organisms based on their shared biogeography.  Biogeographic realms correspond to the [[phytochorion|floristic kingdoms]] of [[botany]] or [[zoogeography|zoogeographic regions]] of [[zoology]].

From 1872, [[Alfred Russel Wallace]] developed a system of zoogeographic regions, extending the [[ornithology|ornithologist]] [[Philip Sclater]]'s system of six regions.<ref name="Holt Lessard Borregaard 2013">{{cite journal |last1=Holt |first1=Ben G. |last2=Lessard |first2=Jean-Philippe |last3=Borregaard |first3=Michael K. |last4=Fritz |first4=Susanne A. |last5=Araújo |first5=Miguel B. |last6=Dimitrov |first6=Dimitar |last7=Fabre |first7=Pierre-Henri |last8=Graham |first8=Catherine H. |last9=Graves |first9=Gary R. |last10=Jønsson |first10=Knud A. |last11=Nogués-Bravo |first11=David |last12=Wang |first12=Zhiheng |last13=Whittaker |first13=Robert J. |last14=Fjeldså |first14=Jon |last15=Rahbek |first15=Carsten |display-authors=3 |title=An Update of Wallace's Zoogeographic Regions of the World |journal=[[Science (journal)|Science]] |volume=339 |issue=6115 |date=4 January 2013 |doi=10.1126/science.1228282 |pages=74–78|pmid=23258408 |bibcode=2013Sci...339...74H |s2cid=1723657 }}</ref>

Biogeographic realms are characterized by the evolutionary history of the organisms they contain. They are distinct from [[biome]]s, also known as major habitat types, which are divisions of the Earth's surface based on ''life form'', or the adaptation of animals, fungi, micro-organisms and plants to climatic, [[soil]], and other conditions. Biomes are characterized by similar [[climax community|climax vegetation]]. Each realm may include a number of different biomes. A [[tropical and subtropical moist broadleaf forests|tropical moist broadleaf forest]] in Central America, for example, may be similar to one in New Guinea in its vegetation type and structure, climate, soils, etc., but these forests are inhabited by animals, fungi, micro-organisms and plants with very different evolutionary histories.{{citation needed|date=August 2021}}

The distribution of organisms among the world's biogeographic realms has been influenced by the distribution of [[landmass|landmass]]es, as shaped by [[plate tectonics]] over the [[geological history of Earth]].

==Concept history==
The "biogeographic realms" of Udvardy{{r|Udvardy1975}} were defined based on taxonomic composition. The rank corresponds more or less to the [[phytochorion|floristic kingdoms]] and [[zoogeography|zoogeographic regions]].

The usage of the term "ecozone" is more variable. Beginning in the 1960s, it was used originally in the field of [[biostratigraphy]] to denote intervals of geological [[stratum|strata]] with fossil content demonstrating a specific ecology.<ref>{{Cite journal |last=Størmer |first=Leif |date=1966-01-01 |title=Concepts of stratigraphical classification and terminology |url=https://dx.doi.org/10.1016/0012-8252%2866%2990039-0 |journal=Earth-Science Reviews |volume=1 |issue=1 |pages=5–28 |doi=10.1016/0012-8252(66)90039-0 |issn=0012-8252|url-access=subscription }}</ref> In Canadian literature, the term was used by Wiken{{r|Wicken1986}} in macro-level [[regionalisation|land classification]], with geographic criteria (see [[Ecozones of Canada]]).{{r|Wicken1986|Scott1995}} Later, Schultz{{r|Schultz1988}} would use it with ecological and physiognomical criteria, in a way similar to the concept of [[biome]].

In the [[Global 200]]/WWF scheme,{{r|OlsonDinerstein1998}} originally the term "biogeographic realm" in Udvardy sense was used. However, in a scheme of [[BBC]],{{r|BBCecozones}} it was replaced by the term "ecozone".

==Terrestrial biogeographic realms==
=== Udvardy biogeographic realms ===
{{Main|List of biogeographic provinces}}

===WWF / Global 200 biogeographic realms===
{{Main|Global 200}}
The [[World Wildlife Fund]] scheme{{r|BBCecozones|OlsonDinerstein1998|OlsonETAL2001}} is broadly similar to [[Miklos Udvardy]]'s system,{{r|Udvardy1975}} the chief difference being the delineation of the Australasian realm relative to the Antarctic, Oceanic, and Indomalayan realms. In the WWF system, the Australasia realm includes [[Australia]], [[Tasmania]], the islands of [[Wallacea]], [[New Guinea]], the [[East Melanesian Islands]], [[New Caledonia]], and [[New Zealand]]. Udvardy's Australian realm includes only Australia and Tasmania; he places [[Wallacea]] in the Indomalayan Realm, New Guinea, New Caledonia, and East Melanesia in the Oceanian Realm, and New Zealand in the Antarctic Realm.

{|class=wikitable
|-
!rowspan=2|Biogeographic<br />realm
!colspan=2|Area
!rowspan=2|Lands included
|-
!million square kilometres
!million square miles
|-
| [[Palearctic realm|Palearctic]]
| {{convert|54.1|km2|disp=table}}
| The bulk of [[Eurasia]] and [[North Africa]].
|-
| [[Nearctic realm|Nearctic]]
| {{convert|22.9|km2|disp=table}}
| [[Greenland]] and most of [[North America]].
|-
| [[Afrotropical realm|Afrotropic]]
| {{convert|22.1|km2|disp=table}}
| [[Sub-Saharan Africa|Trans-Saharan Africa]], [[Madagascar]] and [[Arabian Peninsula|Arabia]].
|-
| [[Neotropical realm|Neotropic]]
| {{convert|19.0|km2|disp=table}}
| [[South America]], [[Central America]], the [[Caribbean]], [[South Florida]] and the [[Falkland Islands]].
|-
| [[Australasian realm|Australasia]]
| {{convert|7.6|km2|disp=table}}
| [[Australia]], [[Melanesia]], [[New Zealand]], [[Lesser Sunda Islands]], [[Sulawesi]], [[Maluku Islands]] and the neighbouring islands. The northern boundary of this zone is known as the [[Wallace Line]].
|-
| [[Indomalayan realm|Indomalaya]]
| {{convert|7.5|km2|disp=table}}
| The [[Indian subcontinent]], [[Southeast Asia]], [[northern and southern China|southern China]] and most of the [[Greater Sunda Islands]].
|-
| [[Oceanian realm|Oceania]]
| {{convert|1.0|km2|disp=table}}
| [[Polynesia]] (except New Zealand), [[Micronesia]], and the [[Fiji|Fijian Islands]].
|-
| [[Antarctic realm|Antarctic]]
| {{convert|0.3|km2|disp=table}}
| [[Antarctica]], [[Alexander Island]], [[South Georgia and the South Sandwich Islands]].
|}

The [[Palearctic realm|Palearctic]] and [[Nearctic realm|Nearctic]] are sometimes grouped into the [[Holarctic realm]].

===Morrone biogeographic kingdoms===
Following the nomenclatural conventions set out in the [[International Code of Area Nomenclature]], Morrone{{r|Morrone2015}} defined the next biogeographic kingdoms (or realms) and regions:
* Holarctic kingdom Heilprin (1887)
** Nearctic region Sclater (1858)
** Palearctic region Sclater (1858)
* Holotropical kingdom Rapoport (1968)
** Neotropical region Sclater (1858)
** Ethiopian region Sclater (1858)
** Oriental region Wallace (1876)
* Austral kingdom Engler (1899)
** Cape region Grisebach (1872)
** Andean region Engler (1882)
** Australian region Sclater (1858)
** Antarctic region Grisebach (1872)
* Transition zones: 
** Mexican transition zone (Nearctic–Neotropical transition)
** Saharo-Arabian transition zone (Palearctic–Ethiopian transition)
** Chinese transition zone (Palearctic–Oriental transition zone transition) 
** Indo-Malayan, Indonesian or Wallace's transition zone (Oriental–Australian transition)
** South American transition zone (Neotropical–Austral transition)

==Freshwater biogeographic realms==
[[Image:Ocean drainage.png|thumb|upright=1.7|right|Major [[continental divide]]s, showing drainage into the major oceans and seas of the world&nbsp;– grey areas are [[endorheic basin]]s that do not drain to the ocean]]

The applicability of Udvardy scheme{{r|Udvardy1975}} to most freshwater taxa is unresolved.{{r|AbellETAL2008}}

The [[drainage basin]]s of the principal oceans and seas of the world are marked by continental divides. The grey areas are [[endorheic basin]]s that do not drain to the ocean.{{citation needed|date=September 2016}}

{{clear}}

==Marine biogeographic realms==
{{Further|Longhurst code}}

[[File:Longhurst biogeographic provinces.png|thumb|upright=1.7|{{center|[[Longhurst code|Longhurst biogeographic provinces]]{{r|Djavidnia2010}}}}]]

According to Briggs{{r|Briggs1995}} and Morrone:{{r|Morrone2009}}

{{columns-list|colwidth=25em|
* [[Indo-Pacific|Indo-West Pacific]] region
* Eastern Pacific region
* Western Atlantic region
* Eastern Atlantic region
* Southern Australian region
* Northern New Zealand region
* Western South America region
* Eastern South America region
* Southern Africa region
* Mediterranean–Atlantic region
* Carolina region
* California region
* Japan region
* Tasmanian region
* Southern New Zealand region
* Antipodean region
* Subantarctic region
* Magellan region
* Eastern Pacific Boreal region
* Western Atlantic Boreal region
* Eastern Atlantic Boreal region
* Antarctic region
* Arctic region
}}

According to the WWF scheme:{{r|SpaldingETAL2007}}

{{columns-list|colwidth=25em|
*[[Arctic realm]]
*[[Temperate Northern Atlantic]] realm
*[[Temperate Northern Pacific]] realm
*[[Tropical Atlantic]] realm
*[[Western Indo-Pacific]] realm
*[[Central Indo-Pacific]] realm
*[[Eastern Indo-Pacific]] realm
*[[Tropical Eastern Pacific]] realm
*[[Temperate South America]] realm
*[[Temperate Southern Africa]] realm
*[[Temperate Australasia]] realm
*[[Southern Ocean]] realm
}}

{{Commons category|Biogeographic realms}}

==See also==
*[[Biome]]
*[[Cosmopolitan distribution]]
*[[Ecotone]]
*[[Phytochorion]] and [[World Geographical Scheme for Recording Plant Distributions]], used in botany

==References==
{{refbegin}}
{{reflist|refs=
<ref name=Udvardy1975>{{cite journal |last=Udvardy |first=Miklos D.F. |date=1975 |title=A classification of the biogeographical provinces of the world |journal=IUCN Occasional Paper |issue=18 |location=[[Morges]] |publisher=International Union for Conservation of Nature and natural resources (IUCN) |url=https://www.iucn.org/content/a-classification-biogeographical-provinces-world }}</ref>

<ref name=Wicken1986>{{Cite web|title=ecozones.ca home page|url=http://www.ecozones.ca/|access-date=2022-12-31|website=www.ecozones.ca}}</ref>

<ref name=Scott1995>{{cite book |last=Scott |first=Geoffrey A.J. |date=1995 |title=Canada's vegetation: a world perspective |publisher=McGill-Queen's Press |at=[https://books.google.com/books?id=QpHCHdrgSVoC&pg=PA13 p. 13]}}</ref>

<ref name=BBCecozones>{{cite web |title=Ecozones |website=BBC Nature |url=https://www.bbc.co.uk/nature/ecozones |archive-date=10 July 2018 |archive-url=https://web.archive.org/web/20180710161951/http://www.bbc.co.uk/nature/ecozones }}</ref>

<ref name=Schultz1988>Schultz, J. ''Die Ökozonen der Erde'', 1st ed., Ulmer, Stuttgart, Germany, 1988, 488 pp.; 2nd ed., 1995, 535 pp.; 3rd ed., 2002.<br>Translated in English as: {{cite book |last=Schultz |first=Jürgen |date=2005 |title=The Ecozones of the World: The Ecological Divisions of the Geosphere |edition=2nd |location=[[Berlin]] |publisher=[[Springer Science+Business Media|Springer]] |isbn=9783540285274 |url=https://books.google.com/books?id=V9L8yPzAjxIC }}</ref>

<ref name=OlsonDinerstein1998>{{cite journal |last1=Olson |first1=David M. |last2=Dinerstein |first2=Eric |date=June 1998 |title=The Global 200: A representation approach to conserving the Earth's most biologically valuable ecoregions |journal=Conservation Biology |volume=12 |issue=3 |doi=10.1046/j.1523-1739.1998.012003502.x |pages=502–515 |bibcode=1998ConBi..12..502O |s2cid=86613942 |url=https://doi.org/10.1046/j.1523-1739.1998.012003502.x |url-access=subscription }}</ref>

<ref name=OlsonETAL2001>Olson, D. M., Dinerstein, E., Wikramanayake, E. D., Burgess, N. D., Powell, G. V. N., Underwood, E. C., D'Amico, J. A., Itoua, I., Strand, H. E., Morrison, J. C., Loucks, C. J., Allnutt, T. F., Ricketts, T. H., Kura, Y., Lamoreux, J. F., Wettengel, W. W., Hedao, P., Kassem, K. R. (2001). [https://web.archive.org/web/20120917072415/http://wolfweb.unr.edu/~ldyer/classes/396/olsonetal.pdf Terrestrial ecoregions of the world: a new map of life on Earth]. ''Bioscience'' '''51'''(11):933-938.</ref>

<ref name=Morrone2015>{{Cite journal|last1=Morrone|first1=Juan J.|date=2015-11-13|title=Biogeographical regionalisation of the world: a reappraisal|url=https://www.publish.csiro.au/sb/SB14042|journal=Australian Systematic Botany|language=en|volume=28|issue=3|pages=81–90|doi=10.1071/SB14042|s2cid=83401946 |issn=1446-5701|url-access=subscription}}</ref>

<ref name=AbellETAL2008>{{Cite web|title=Freshwater Ecoregions of the World|url=https://www.feow.org/downloads/Abell_et_al_08_BioScience.pdf|access-date=2022-12-31|website=www.feow.org}}</ref>

<ref name=Djavidnia2010>{{cite journal |last1=Djavidnia |first1=S. |last2=Mélin |first2=F. |last3=Hoepffner |first3=N. |date=2010 |title=Comparison of global ocean colour data records |journal=Ocean Science |volume=6 |issue=1 |pages=61–76 |doi=10.5194/os-6-61-2010 |bibcode=2010OcSci...6...61D |doi-access=free }}</ref>

<ref name=Briggs1995>{{cite book |last=Briggs |first=J.C. |date=1995 |title=Global Biogeography |series=Developments in Palaeontology and Stratigraphy n. 14 |location=[[Amsterdam]] |publisher=Elsevier |isbn=9780444825605 }}</ref>

<ref name=Morrone2009>{{cite book |last=Morrone |first=J.J. |date=2009 |title=Evolutionary biogeography, an integrative approach with case studies |location=New York City |publisher=Columbia University Press |isbn=9780231512831 |url=https://books.google.com/books?id=ednrWpMF3bMC }}</ref>

<ref name=SpaldingETAL2007>{{cite journal |last1=Spalding |first1=Mark D. |first2=Helen E. |last2=Fox |first3=Gerald R. |last3=Allen |first4=Nick |last4=Davidson |first5=Zach A. |last5=Ferdaña |first6=Max |last6=Finlayson |first7=Benjamin S. |last7=Halpern |first8=Miguel A. |last8=Jorge |first9=Al |last9=Lombana |first10=Sara A. |last10=Lourie |first11=Kirsten D. |last11=Martin |first12=Edmund |last12=Mcmanus |first13=Jennifer |last13=Molnar |first14=Cheri A. |last14=Recchia |first15=James |last15=Robertson |display-authors=4 |date=2007 |title=Marine ecoregions of the world: a bioregionalization of coastal and shelf areas |journal=BioScience |volume=57 |issue=7 |pages=573–583 |doi=10.1641/B570707 |s2cid=29150840 |url=http://algae.thu.edu.tw/lab/2013_Meeting_FebJune/2007_Marine_ecoregions_of_the_world.pdf |archive-date=6 October 2016 |access-date=18 May 2021 |archive-url=https://web.archive.org/web/20161006104440/http://algae.thu.edu.tw/lab/2013_Meeting_FebJune/2007_Marine_ecoregions_of_the_world.pdf]}}</ref>
}}
{{refend}}

{{Biomes}}

[[Category:Biogeography]]
[[Category:Habitat]]
[[Category:Biogeographic realms| ]]