Australasia is a unique geographical and ecological zone compromised of Australia, New Zealand, New Guinea, and other small islands nearby. This region sits upon the Indo-Australian Tectonic Plate and has a variety of unique human and ecological features that set it apart from other geographic and ecological zones around the world.
Australasia is a part of Oceania, a bigger region that includes, in some opinions, the area between Asia and the Americas and the assorted continents and islands that lie within those large boundaries. Australasia is different than Polynesia and Micronesia.
The Australasian zone is different from other zones because of three factors: geography, ecology, and humanity. Geographically speaking the Australasian zone is unlike any other in terms of shape, the mass and force of the tectonic plate, and the way in which it interacts with the other tectonic plates around it.
Australia and New Zealand are extraordinary landforms with mountains, deserts, sea marshes and tropical rainforests spread across their mass.
The Wallace Line, a faunal boundary line discovered and mapped by Alfred Russel Wallace in 1859, delineates an area of separation between Southeast Asian fauna and those coming from the Australasian side.
Although the line is imperfect in some areas there is a distinct difference to be seen and studied on each side of the Wallace Line. The Wallace Line runs between the continent of Australia and Southeast Asia.
The Wallace Line also marks the rough border of the Australasia eco-zone. This region contains Australia, New Guinea, New Zealand, New Caledonia, and a few other neighboring islands. The northernmost part of Australasia shares common flora and fauna with the Southeast Asian zone while the rest of the region has flora also seen in Antarctica.
When the islands and continents of Australasia were linked together as one landmass or connected through their barely-submerged continental shelves they shared common plants and animals that are still seen on their shores, despite the present-day distance between the landmasses.
The way the Australasian geographic and ecological zone broke away from the rest of the earth’s landmass can be traced by studying the commonalities between Australasia and neighboring areas with the same characteristics.
Flora and Fauna
Australia, New Guinea, and Tasmania all have the same marsupials, monotreme mammals, and ratite birds in common. Eucalyptus trees can be found scattered across Australia and in New Guinea, while New Zealand has some now extinct bird species in common with the rest of the Australasian zone.
Bats were also found in New Zealand until humans arrived, and as people began to populate the island more and more different plants and animals began dying off. The climate changes that occurred in the past and that are occurring today also hastened the extinction of a few species of plants and animals native to New Zealand, including crocodiles and turtles.
Australasia has 13 endemic bird families including emus, cassowaries, kiwi, kagu, cockatoos, honeyeaters, and birds of paradise. Large reptiles, including monitor lizards, komodo dragons, and crocodiles are an ecologically important predators in the Australasian geographical and eco-zone.
The human factor is another major characteristic of Australasia. Humans first introduced dingoes, dogs and pigs to Australia and New Guinea when the region was first inhabited by humans many thousands of years ago.
With the increased number of people emigrating to Australia and the surrounding islands not only did the local eco-system begin to change, but many patterns of life were disrupted and never recovered.
The Australasian geographical zone is unique not only for its location in the grand scheme of the world, but for the geographical features that make it different from any other place on the planet. The Australasian zone contains geographical characteristics unlike anywhere else, but shares common land masses, flora and fauna with areas in Antarctica, Southeast Asia, and its neighboring islands in the Pacific Ocean.
With the arrival of humans on the shores of the islands that make up Australasia many plant and animal species became extinct or endangered, and extensive ecological conservation work continues to be done today to keep further damage from happening to this fragile ecosystem.
The Australasian zone is special and deserves increased amount of attention and study in the world today by geographers, ecologists, environmental conservationists, and others.
Red Orbit. Australasia Ecozone. 2014. http://www.redorbit.com/education/reference_library/earth/geography/2582382/australasia_ecozone/
Richards, Kel. “Australasia”. Wordwatch. ABC News Radio. 2006.
Map: Olson, D. M., E. Dinerstein, E. D. Wikramanayake, N. D. Burgess, G. V. N. Powell, E. C. Underwood, J. A. D’Amico, I. Itoua, H. E. Strand, J. C. Morrison, C. J. Loucks, T. F. Allnutt, T. H. Ricketts, Y. Kura, J. F. Lamoreux, W. W. Wettengel, P. Hedao, and K. R. Kassem. 2001. Terrestrial ecoregions of the world: a new map of life on Earth. BioScience 51:933-938.