The World Wide Fund for Nature (WWF) identified 825 terrestrial ecoregions that cover the Earth's land surface, 40 of which cover Australia and its dependent islands. The WWF ecoregions are classified by biome type (Tropical and subtropical moist broadleaf forests, Temperate grasslands, savannas, and shrublands, tundra, etc.), and into one of eight terrestrial ecozones. Australia, together with New Zealand, New Guinea and neighboring island groups, is part of the Australasia ecozone. The IBRA bioregions informed the delineation of the WWF ecoregions for Australia, and the WWF ecoregions generally follow the same ecoregion boundaries, while often clustering two or more similar bioregions into a larger ecoregion. The ecoregion articles in Wikipedia generally follow the WWF scheme.
The WWF ecoregions are based heavily upon the Interim Biogeographic Regionalisation for Australia (IBRA) regionalisation. Like the IBRA, it was developed for use as a planning tool for conservation science, with the goal of establishing a system of nature reserves in each of the ecoregions or bioregions sufficient to preserve biodiversity. Both systems also have a prioritization system for establishing preserves; the WWF designated its Global 200 ecoregions as priorities for conservation, and the Department of Environment and Heritage ranks its bioregions high, medium, or low priority, based on "the potential value land reservation in those regions would add to the development of a comprehensive, adequate and representative reserve system for Australia."