The following is a list of ecoregions in Indonesia. An ecoregion is defined by the WWF as a "large area of land or water that contains a geographically distinct assemblage of natural communities". There are terrestrial, freshwater, and marine ecoregions. Ecoregions classified into biomes or major habitat types.
Indonesia straddles two of the Earth's biogeographical realms, large-scale divisions of the Earth's surface based on the historic and evolutionary distribution patterns of plants and animals. Realms are subdivided into bioregions (and marine realms into provinces), which are in turn made up of multiple ecoregions. The Indomalayan realm extends across the western half of the archipelago, and the eastern half is in the Australasian realm. The Wallace Line, which runs between Borneo and Sulawesi, Bali and Lombok, is the dividing line.
The portion of Indonesia west of the Wallace Line is known as the Sundaland bioregion, which also includes Malaysia and Brunei. When sea levels fell during the ice ages, the shallow Sunda Shelf was exposed, linking the Islands of Sundaland to the Asian continent. Sundaland has many large mammals of Asian origin, including rhinoceros, Asian elephants, and apes.
East of the Wallace Line lies the Wallacea bioregion, made up of islands that were never linked to a continent, but were instead pushed up by the Australian continent's northward movement. Wallacea is a transitional region between Asia and Australia. It has a flora of mostly Indomalayan origin, with elements from Australasia, with a reptile and bird fauna of mainly Australian origin and no large mammal fauna.
The Aru Islands and the Indonesian portion of New Guinea are connected by the shallow Sahul Shelf to the Australian continent, and were connected by land during the ice ages. New Guinea has a flora of chiefly Asian origin with many Australasian elements, and a fauna similar to that of Australia.
See main article: Sundaland.
See main article: Wallacea.
See main article: Ecoregions of New Guinea.
See main article: Sundaland.
See main article: Ecoregions of the Philippines.
See main article: Wallacea.
See main article: New Guinea.
See main article: Western Indo-Pacific.
See main article: Central Indo-Pacific.