From an ecological perspective the Australasian realm is a distinct region, parts of which have a common geologic and evolutionary history. The entire area has experienced a long period of biological isolation from other regions, and thus harbors a great many unique plants and animals. In this context, Australasia is limited to Australia, New Guinea, New Zealand, New Caledonia, and neighbouring islands, including the Indonesian islands from Lombok and Sulawesi eastward.
The Wallace Line to the west divides areas in the Indomalayan realm of tropical Asia which are or have at times been directly connected to the Asian mainland from islands that have never been so connected. Borneo and Bali lie on the western, Asian side. A second biological dividing line is Lydekker's Line, which similarly separates islands isolated by surrounding deep water from those associated with the Sahul Shelf of the Australian continent. Islands between the two lines (e.g. Sulawesi, the Moluccas and Lombok through Timor) form the biogeographical area of Wallacea, a transition zone between the Indomalayan and Australasian realms populated entirely by aerial or oceanic dispersal (although defined here as part of the Australasian realm).
Geologyedit
Australia, New Zealand and New Caledonia are all fragments of the ancient supercontinent Gondwana, the marks of which are still visible in the Christmas Island Seamount Province and other geophysical entities. These three land masses have been separated from other continents, and from one another, for tens millions of years. All of Australasia shares the Antarctic flora, although the northern, tropical islands also share many plants with Southeast Asia.
Australia, New Guinea, and Tasmania are separated from one another by shallow continental shelves, and were linked together when the sea level was lower during ice ages. They share a similar fauna which includes marsupial and monotreme mammals and ratite birds. Eucalypts are the predominant trees in much of Australia and New Guinea. New Zealand has no native land mammals, but also had ratite birds, including the kiwi and the moa. The Australasian realm includes some nearby island groups, like Wallacea, the Bismarck Archipelago, Solomon Islands, and Vanuatu, which were not formerly part of Gondwana, but which share many characteristic plants and animals with Australasia.
Ecologyedit
Note that this zonation is based on flora; animals do not necessarily follow the same biogeographic boundaries. In the present case, many birds occur in both "Indomalayan" and "Australasian" regions, but not across the whole of either. On the other hand, there are few faunistic commonalities shared only by Australia and New Zealand, except some birds. Meanwhile, Australia, Melanesia and the Wallacea are united by a large share of similar animals, but few of these occur farther into the Pacific. On the other hand, much of the Polynesian fauna is related to that of Melanesia.
^. World Wildlife Fund. Archived from the original on 2006-10-07.
^Udvardy, M. D. F. (1975). A classification of the biogeographical provinces of the world. IUCN Occasional Paper no. 18. Morges, Switzerland: IUCN.
^Udvardy, Miklos D. F. (1975) World Biogeographical Provinces (Map). The CoEvolution Quarterly, Sausalito, California. link.
External linksedit
Wikimedia Commons has media related to Australasian realm.
Wikivoyage has a travel guide for Australasian wildlife.
Panda.org: Map of the Ecozones
February 15, 2024
australasian, realm, eight, biogeographic, realms, that, coincident, with, some, definitions, same, geographical, region, australasia, realm, includes, australia, island, guinea, comprising, papua, guinea, indonesian, province, papua, eastern, part, indonesian. The Australasian realm is one of eight biogeographic realms that is coincident with but not by some definitions the same as the geographical region of Australasia The realm includes Australia the island of New Guinea comprising Papua New Guinea and the Indonesian province of Papua and the eastern part of the Indonesian archipelago including the island of Sulawesi the Moluccas the Indonesian provinces of Maluku and North Maluku and the islands of Lombok Sumbawa Sumba Flores and Timor often known as the Lesser Sundas The Australasian realmThe Australasian realm also includes several Pacific island groups including the Bismarck Archipelago Vanuatu the Solomon Islands and New Caledonia New Zealand and its surrounding islands are a distinctive sub region of the Australasian realm The rest of Indonesia is part of the Indomalayan realm 1 In the classification scheme developed by Miklos Udvardy New Guinea New Caledonia Solomon Islands and New Zealand are placed in the Oceanian realm 2 3 Contents 1 Geography 2 Geology 3 Ecology 4 Ecoregions 5 See also 6 References 7 External linksGeography editFrom an ecological perspective the Australasian realm is a distinct region parts of which have a common geologic and evolutionary history The entire area has experienced a long period of biological isolation from other regions and thus harbors a great many unique plants and animals In this context Australasia is limited to Australia New Guinea New Zealand New Caledonia and neighbouring islands including the Indonesian islands from Lombok and Sulawesi eastward The Wallace Line to the west divides areas in the Indomalayan realm of tropical Asia which are or have at times been directly connected to the Asian mainland from islands that have never been so connected Borneo and Bali lie on the western Asian side A second biological dividing line is Lydekker s Line which similarly separates islands isolated by surrounding deep water from those associated with the Sahul Shelf of the Australian continent Islands between the two lines e g Sulawesi the Moluccas and Lombok through Timor form the biogeographical area of Wallacea a transition zone between the Indomalayan and Australasian realms populated entirely by aerial or oceanic dispersal although defined here as part of the Australasian realm Geology editAustralia New Zealand and New Caledonia are all fragments of the ancient supercontinent Gondwana the marks of which are still visible in the Christmas Island Seamount Province and other geophysical entities These three land masses have been separated from other continents and from one another for tens millions of years All of Australasia shares the Antarctic flora although the northern tropical islands also share many plants with Southeast Asia Australia New Guinea and Tasmania are separated from one another by shallow continental shelves and were linked together when the sea level was lower during ice ages They share a similar fauna which includes marsupial and monotreme mammals and ratite birds Eucalypts are the predominant trees in much of Australia and New Guinea New Zealand has no native land mammals but also had ratite birds including the kiwi and the moa The Australasian realm includes some nearby island groups like Wallacea the Bismarck Archipelago Solomon Islands and Vanuatu which were not formerly part of Gondwana but which share many characteristic plants and animals with Australasia Ecology editNote that this zonation is based on flora animals do not necessarily follow the same biogeographic boundaries In the present case many birds occur in both Indomalayan and Australasian regions but not across the whole of either On the other hand there are few faunistic commonalities shared only by Australia and New Zealand except some birds Meanwhile Australia Melanesia and the Wallacea are united by a large share of similar animals but few of these occur farther into the Pacific On the other hand much of the Polynesian fauna is related to that of Melanesia Ecoregions edit nbsp Ecoregions of the Australasian realm color coded by biome Dark green tropical and subtropical moist broadleaf forests Light brown tropical and subtropical dry broadleaf forests Yellow tropical and subtropical grasslands savannas and shrublands Green temperate broadleaf and mixed forests Light green temperate grasslands savannas and shrublands Light blue flooded grasslands and savannas Light purple montane grasslands and shrublands Brown Mediterranean forests woodlands and scrub Beige deserts and xeric shrublands Magenta mangroves Australasian tropical and subtropical moist broadleaf forests ecoregionsvteAdmiralty Islands lowland rain forests Papua New GuineaBanda Sea Islands moist deciduous forests IndonesiaBiak Numfoor rain forests IndonesiaBuru rain forests IndonesiaCentral Range montane rain forests Indonesia Papua New GuineaHalmahera rain forests IndonesiaHuon Peninsula montane rain forests Papua New GuineaLord Howe Island subtropical forests AustraliaLouisiade Archipelago rain forests Papua New GuineaNew Britain New Ireland lowland rain forests Papua New GuineaNew Britain New Ireland montane rain forests Papua New GuineaNew Caledonia rain forests New CaledoniaNorfolk Island subtropical forests AustraliaNorthern New Guinea lowland rain and freshwater swamp forests Indonesia Papua New GuineaNorthern New Guinea montane rain forests Indonesia Papua New GuineaQueensland tropical rain forests AustraliaSeram rain forests IndonesiaSolomon Islands rain forests Papua New Guinea Solomon IslandsSoutheastern Papuan rain forests Papua New GuineaSouthern New Guinea freshwater swamp forests Indonesia Papua New GuineaSouthern New Guinea lowland rain forests Indonesia Papua New GuineaSulawesi lowland rain forests IndonesiaSulawesi montane rain forests IndonesiaTrobriand Islands rain forests Papua New GuineaVanuatu rain forests Solomon Islands VanuatuVogelkop montane rain forests IndonesiaVogelkop Aru lowland rain forests IndonesiaYapen rain forests IndonesiaAustralasian tropical and subtropical dry broadleaf forests ecoregionsvteLesser Sundas deciduous forests IndonesiaNew Caledonia dry forests New CaledoniaSumba deciduous forests IndonesiaTimor and Wetar deciduous forests Indonesia Timor LesteAustralasian tropical and subtropical grasslands savannas and shrublands ecoregionsvteArnhem Land tropical savanna AustraliaBrigalow tropical savanna AustraliaCape York Peninsula tropical savanna AustraliaCarpentaria tropical savanna AustraliaEinasleigh Uplands savanna AustraliaKimberley tropical savanna AustraliaMitchell grass downs AustraliaTrans Fly savanna and grasslands Indonesia Papua New GuineaVictoria Plains tropical savanna AustraliaAustralasian temperate broadleaf and mixed forests ecoregionsvteChatham Islands temperate forests New ZealandEastern Australian temperate forests AustraliaFiordland temperate forests New ZealandNelson Coast temperate forests New ZealandNorth Island temperate forests New ZealandNorthland temperate kauri forests New ZealandStewart Island Rakiura temperate forests New ZealandRichmond temperate forests New ZealandSoutheast Australia temperate forests AustraliaSouthland temperate forests New ZealandTasmanian Central Highland forests AustraliaTasmanian temperate forests AustraliaTasmanian temperate rain forests AustraliaWestland temperate forests New ZealandAustralasian temperate grasslands savannas and shrublands ecoregionsvteCanterbury Otago tussock grasslands New ZealandSoutheast Australia temperate savanna AustraliaSouthwest Australia savanna AustraliaAustralasian montane grasslands and shrublands ecoregionsvteAustralian Alps montane grasslands AustraliaCentral Range sub alpine grasslands Indonesia Papua New GuineaSouthland montane grasslands New ZealandAustralasian Mediterranean forests woodlands and scrub ecoregionsvteCoolgardie woodlands AustraliaEsperance mallee AustraliaEyre and York mallee AustraliaJarrah Karri forest and shrublands AustraliaSwan Coastal Plain scrub and woodlands AustraliaMount Lofty woodlands AustraliaMurray Darling woodlands and mallee AustraliaNaracoorte woodlands AustraliaSouthwest Australia woodlands AustraliaAustralasian deserts and xeric shrublands ecoregionsvteCarnarvon xeric shrublands AustraliaCentral Ranges xeric scrub AustraliaGibson Desert AustraliaGreat Sandy Tanami desert AustraliaGreat Victoria Desert AustraliaNullarbor Plain xeric shrublands AustraliaPilbara shrublands AustraliaSimpson Desert AustraliaTirari Sturt stony desert AustraliaWestern Australian mulga shrublands AustraliaAustralasian tundra ecoregionsvteAntipodes Subantarctic Islands tundra Australia New ZealandAustralasian mangroves ecoregionsvteNew Guinea mangroves New GuineaAustralian mangroves AustraliaSee also editAustralasia OceaniaReferences edit Australasia ecozone World Wildlife Fund Archived from the original on 2006 10 07 Udvardy M D F 1975 A classification of the biogeographical provinces of the world IUCN Occasional Paper no 18 Morges Switzerland IUCN Udvardy Miklos D F 1975 World Biogeographical Provinces Map The CoEvolution Quarterly Sausalito California link External links edit nbsp Wikimedia Commons has media related to Australasian realm nbsp Wikivoyage has a travel guide for Australasian wildlife Panda org Map of the Ecozones Retrieved from https en wikipedia org w index php title Australasian realm amp oldid 1198267229, wikipedia, wiki, book, books, library,
