Australasian realm

The Australasian realm is one of eight

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 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]

Geography

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

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

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.

Ecology

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.

Ecoregions

mangroves

.

Australasian tropical and subtropical moist broadleaf forests ecoregions v t e
Admiralty Islands lowland rain forests	Papua New Guinea
Banda Sea Islands moist deciduous forests	Indonesia
Biak–Numfoor rain forests	Indonesia
Buru rain forests	Indonesia
Central Range montane rain forests	Indonesia, Papua New Guinea
Halmahera rain forests	Indonesia
Huon Peninsula montane rain forests	Papua New Guinea
Lord Howe Island subtropical forests	Australia
Louisiade Archipelago rain forests	Papua New Guinea
New Britain–New Ireland lowland rain forests	Papua New Guinea
New Britain–New Ireland montane rain forests	Papua New Guinea
New Caledonia rain forests	New Caledonia
Norfolk Island subtropical forests	Australia
Northern New Guinea lowland rain and freshwater swamp forests	Indonesia, Papua New Guinea
Northern New Guinea montane rain forests	Indonesia, Papua New Guinea
Queensland tropical rain forests	Australia
Seram rain forests	Indonesia
Solomon Islands rain forests	Papua New Guinea, Solomon Islands
Southeastern Papuan rain forests	Papua New Guinea
Southern New Guinea freshwater swamp forests	Indonesia, Papua New Guinea
Southern New Guinea lowland rain forests	Indonesia, Papua New Guinea
Sulawesi lowland rain forests	Indonesia
Sulawesi montane rain forests	Indonesia
Trobriand Islands rain forests	Papua New Guinea
Vanuatu rain forests	Solomon Islands, Vanuatu
Vogelkop montane rain forests	Indonesia
Vogelkop–Aru lowland rain forests	Indonesia
Yapen rain forests	Indonesia

Australasian tropical and subtropical dry broadleaf forests ecoregions v t e
Lesser Sundas deciduous forests	Indonesia
New Caledonia dry forests	New Caledonia
Sumba deciduous forests	Indonesia
Timor and Wetar deciduous forests	Timor-Leste

Australasian tropical and subtropical grasslands, savannas, and shrublands ecoregions v t e
Arnhem Land tropical savanna	Australia
Brigalow tropical savanna	Australia
Cape York Peninsula tropical savanna	Australia
Carpentaria tropical savanna	Australia
Einasleigh Uplands savanna	Australia
Kimberley tropical savanna	Australia
Mitchell grass downs	Australia
Trans-Fly savanna and grasslands	Indonesia, Papua New Guinea
Victoria Plains tropical savanna	Australia

Australasian temperate broadleaf and mixed forests ecoregions v t e
Chatham Islands temperate forests	New Zealand
Eastern Australian temperate forests	Australia
Fiordland temperate forests	New Zealand
Nelson Coast temperate forests	New Zealand
North Island temperate forests	New Zealand
Northland temperate kauri forests	New Zealand
Stewart Island / Rakiura temperate forests	New Zealand
Richmond temperate forests	New Zealand
Southeast Australia temperate forests	Australia
Southland temperate forests	New Zealand
Tasmanian Central Highland forests	Australia
Tasmanian temperate forests	Australia
Tasmanian temperate rain forests	Australia
Westland temperate forests	New Zealand

Australasian temperate grasslands, savannas, and shrublands ecoregions v t e
Canterbury–Otago tussock grasslands	New Zealand
Southeast Australia temperate savanna	Australia
Southwest Australia savanna	Australia

Australasian montane grasslands and shrublands ecoregions v t e
Australian Alps montane grasslands	Australia
Central Range sub-alpine grasslands	Indonesia, Papua New Guinea
Southland montane grasslands	New Zealand

Australasian Mediterranean forests, woodlands, and scrub ecoregions v t e
Coolgardie woodlands	Australia
Esperance mallee	Australia
Eyre and York mallee	Australia
Jarrah-Karri forest and shrublands	Australia
Swan Coastal Plain scrub and woodlands	Australia
Mount Lofty woodlands	Australia
Murray-Darling woodlands and mallee	Australia
Naracoorte woodlands	Australia
Southwest Australia woodlands	Australia

Australasian deserts and xeric shrublands ecoregions v t e
Carnarvon xeric shrublands	Australia
Central Ranges xeric scrub	Australia
Gibson Desert	Australia
Great Sandy-Tanami desert	Australia
Great Victoria Desert	Australia
Nullarbor Plain xeric shrublands	Australia
Pilbara shrublands	Australia
Simpson Desert	Australia
Tirari–Sturt stony desert	Australia
Western Australian mulga shrublands	Australia

Australasian tundra ecoregions v t e
Antipodes Subantarctic Islands tundra	Australia, New Zealand

Australasian mangroves ecoregions v t e
New Guinea mangroves	New Guinea
Australian mangroves	Australia

References

^ "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

Panda.org: Map of the Ecozones

[1] "Australasia ecozone". World Wildlife Fund. Archived from the original on 2006-10-07.

[Udvardy75-2] Udvardy, M. D. F. (1975). A classification of the biogeographical provinces of the world. IUCN Occasional Paper no. 18. Morges, Switzerland: IUCN.

[3] Udvardy, Miklos D. F. (1975) World Biogeographical Provinces (Map). The CoEvolution Quarterly, Sausalito, California. link.

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