, or major habitat types, as defined by Olson & Dinerstein, et al. (2001). The
World Wildlife Fund (WWF) divides Indomalayan realm into three bio-regions, which it defines as "geographic clusters of eco-regions that may span several habitat types, but have strong biogeographic affinities, particularly at taxonomic levels higher than the species level (genus, family)".
Indian subcontinent The
Indian subcontinent bioregion covers most of
India,
Bangladesh,
Nepal,
Bhutan, and
Sri Lanka and eastern parts of
Pakistan. The
Hindu Kush,
Karakoram,
Himalaya, and
Patkai ranges bound the bioregion on the northwest, north, and northeast; these ranges were formed by the collision of the northward-drifting Indian subcontinent with Asia beginning 45 million years ago. The Hindu Kush, Karakoram, and Himalaya are a major biogeographic boundary between the subtropical and tropical flora and fauna of the Indian subcontinent and the temperate-climate
Palearctic realm.
Indochina The Indochina bioregion includes most of
Mainland Southeast Asia, including
Myanmar,
Thailand,
Laos,
Vietnam, and
Cambodia, as well as the subtropical forests of southern
China.
Sunda Shelf and the Philippines Malesia is a botanical province which straddles the boundary between Indomalaya and Australasia. It includes the
Malay Peninsula and the western Indonesian islands (known as
Sundaland), the Philippines, the eastern Indonesian islands, and New Guinea. While the Malesia has much in common botanically, the portions east and west of the
Wallace Line differ greatly in land animal species; Sundaland shares its fauna with mainland Asia, while terrestrial fauna on the islands east of the Wallace line are derived at least in part from species of
Australian origin, such as
marsupial mammals and
ratite birds. == History ==