Fauna of Indonesia

From Wikipedia, the free encyclopedia

The Sumatran Tiger, the smallest tiger subspecies only found in Indonesia

The Fauna of Indonesia consists of a high level of biodiversity due to its vast-size and tropical archipelago make-up.^[1] This high biodiversity level is the result of the Wallace Line, dividing Indonesia into three regions; Asian zoogeographical regions, in which influenced by Asian fauna, and Australasian zoogeographical regions, brings more influences from Australian fauna.^[2] This unique blend of fauna in Indonesia is also affected by the diverse range of ecosystems, including beaches, sand dunes, estuaries, mangroves, coral reefs, sea grass beds, coastal mudflats, tidal flats, algal beds, and small island ecosystems.

Ecological issues have appeared in the nation due to the rapid industrialisation process and high population growth, resulting in lower priority level to preserve the ecosystems.^[3] The situation has worsened by illegal logging activity, in which resulting deforestation; while other problems, including high level of urbanisation, air pollution, garbage management and waste water services also contributing to the forest deterioration.

1 Origin of Indonesian fauna
2 Sundaland
- 2.1 Mammals
3 Wallacea
4 Conservation
5 Notes
6 See also

[edit] Origin of Indonesian fauna

The Wallace Line, dividing Indonesian fauna into two categories

The origin of fauna in Indonesia is heavily affected by geographical and geological events in Asian continent and Australasian continent (now Australia).^[4] The present New Guinea island was connected with the present Australia continent, forming a supercontinent called the southern supercontinent Gondwana. This supercontinent began to break up 140 million years ago, and the New Guinea region (previously known as Sahul) moved towards the equator. As a result, animals from New Guinea traveled to Australian continent and vice versa, creating many different species living in different ecosystems. This activities still occur until the two regions separated completely.

Asian continent influences, on the other hand, is the result of the reformation of the Laurasia supercontinent, which existed after the breakup of Rodinia around 1 billion years ago. Around 200 million years ago, the Laurasia supercontinent splitted completely, forming Laurentia (now America) and Eurasia continents. Although this occurred, the mainland of the Eurasia continent, including China, was not separated completely from the Indonesian archipelago. As a result, animals from the Eurasia mainland could travel to the archipelago, and, under a different ecosystems, new forms of species were formed.

In the nineteenth century, Alfred Russel Wallace proposed the idea of the Wallace Line, which is a line that divides Indonesian archipelago into two regions, Asian zoogeographical regions (Sundaland) and Australasian zoogeographical regions (Wallacea).^[5] The line runs through the Malay Archipelago, between Borneo and Sulawesi (Celebes); and between Bali and Lombok.^[6] Although the distance from Bali to Lombok is relatively short, only about 35 kilometres, the fauna distribution is still affected by the line. For example, a group of birds would refuse to cross even the smallest stretches of open water.^[6]

See also: Wallace Line

[edit] Sundaland

Main article: Sundaland

The animals in Sundaland region, which includes Sumatra, Java, Borneo and smaller surrounding islands, share the similar characteristics with Asian fauna. During the ice age, after the Laurasia break up, the main Asian continent was connected with the Indonesian archipelago. Moreover, a low sea level enabled animals from Asian migrated to Sundaland. Large species such as tiger, rhinoceros, orangutan, elephant, and leopard exist in this region, although some species are categorised as endagered species. The Makassar Strait, between Borneo and Sulawesi, and the Lombok Strait, between Bali and Lombok, which is the Wallace Line separator, mark the end of the Sundaland region.

[edit] Mammals

The Borneo Elephant, an Asian Elephant subspecies

[edit] Wallacea

Main article: Wallacea

[edit] Conservation

The critically endangered Sumatran Orangutan, a great ape endemic to Indonesia

Although 45% of Indonesian region is still inhabitted and covered by tropical forests, high growth of Indonesian population, with its industrialisation, has slowly affected the existence of fauna in Indonesia.^[3] Up to 95% of animals sold in markets are taken directly from the wild, rather than from conservations; and more than 20% of the animals died in transportation.^[7] As of 2003, The World Conservation Union lists as endangered 147 mammals, 114 birds, 91 fish and 2 invertebrate species.^[7]