The ecozones are based largely on the biogeographic realms of Pielou (1979) and Udvardy (1975). A team of biologists convened by the World Wildlife Fund (WWF) developed a system of eight biogeographic realms (ecozones) as part of their delineation of the world's over 800 terrestrial ecoregions.
* Nearctic 54.1 mil. km² (including most of North America)
* Palearctic 87.7 mil. km² (including the bulk of Eurasia and North Africa)
* Afrotropic 22.1 mil. km² (including Sub-Saharan Africa)
* Indo-Malaya 7.5 mil. km² (including Afghanistan and Pakistan, the South Asian subcontinent and Southeast Asia)
* Australasia 7.6 mil. km² (including Australia, New Guinea, and neighbouring islands). The northern boundary of this zone is known as the Wallace line.
* Neotropic 19.0 mil. km² (including South America and the Caribbean)
* Oceania 1.0 mil. km² (including Polynesia, Fiji and Micronesia)
* Antarctic 0.3 mil. km² (including Antarctica).
The WWF scheme is broadly similar to Udvardy's system, the chief difference being the delineation of the Australasian ecozone relative to the Antarctic, Oceanic, and Indomalayan ecozones. In the WWF system, The Australasia ecozone 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.
Source: Wiki
