Malaysia is one of the twelve "megadiversity" countries of the world. These countries together contain at least 60 percent of the world's known species. The island of Borneo containing the states of Sabah and Sarawak has been listed as one key area for endemism.
Flora
The flora of Malaysia is exceedingly rich and is conservatively estimated to contain about 12,500 species of flowering plants, and more than 1,100 species of ferns and fern allies. Many of these are unique and are found nowhere else in the world. In Peninsular Malaysia, for example, well over 26% of the tree species are endemic. Higher endemism is expected in the herbaceous flora with some of the larger genera estimated to be endemic in more than 80% of their species. Many endemic plants are localised in their distribution, being found only in a few valleys or mountain tops.
Much remains to be known of the flora of the country, especially of lower plants such as the bryophytes, algae, lichens and fungi. The fungi constitute the major plant diversity of the country but the total number of species is not known.
The terrestrial flora, as well as fauna, are found in a range of habitats and ecosystems from the lowlands to the top of the highest mountains, and in a wide range of forest types. These forest types form the cradle of the country's biological diversity. The lowland dipterocarp forest is extremely rich in species diversity. For example, 814 species of woody plants of 1 cm diameter and larger were found in a 50 hectare area in such a forest type. Now not much remains of this forest type due mainly to agricultural expansion.
Endemism in plant species is high in freshwater habitats. In Peninsular Malaysia, for example, 80 species in freshwater swamps and 27 species in river systems are known to be endemic. Another 70 and 41 species respectively are known to be rare.
The marine ecosystem surrounding the country's landmass, which includes the coral reefs, is extremely rich in the variety of life-forms. The coral reef community in Malaysia is considered to be one of the most diverse in the world. But the marine flora and fauna have been poorly documented. The flora include phytoplankton, seaweeds and sea grasses.
Fauna
There is an even greater diversity of fauna in the country. In the vertebrates, there are about 300 species of wild mammals, 700-750 species of birds, 350 species of reptiles, 165 species of amphibians and more than 300 species of freshwater fish. Endemism in the states of Sabah and Sarawak is higher than in Peninsular Malaysia. While there are about 1,200 species of butterflies and 12,000 species of moths in Malaysia, little is known of other groups. A conservative estimate is that there are more than 100,000 species of invertebrates.
Freshwater habitats such as the lowland slow-flowing streams and upland rivers with water torrents support a diverse aquatic invertebrate fauna and a variety of fish. Marine fauna include fish, cuttlefish, squids, sea urchins, giant clams, sea cucumbers, copepods, segestid shrimps, arrow worms and many other large and small organisms.
