Nature

Indonesia's vast size, tropical climate and archipelagic geography, supports the world's second highest level of biodiversity (after Brazil); 45% of the country is covered by forests and its flora and fauna is a mixture of Asian and Australasian species. Surrounding thousands of islands with over 80,000 kilometres of coastline, the warm, tropical seas of Indonesia boast a high level of biodiversity, with a corresponding diverse range of ecosystems that include beaches, sand dunes, estuaries, mangroves, coral reefs, sea grass beds, coastal mudflats, tidal flats, algal beds, and small island ecosystems.

Once linked to the Asian mainland, the Greater Sunda Islands (Sumatra, Kalimantan, Java and Bali) have a wealth of Asian fauna. Large species such as the tiger, rhinoceros, orangutan, elephant, and leopard, although once abundant and distributed east as far as Bali, have dwindled drastically in number and distribution. Sumatra and Kalimantan still contain vast forests, predominantly of Asian species, but they are being logged at rapid rates. In contrast, the forests of smaller but densely populated Java have largely been removed for human habitation and agriculture. Sulawesi, Nusa Tenggara and Maluku, having been long separated from the continental landmasses, have developed their own unique flora and fauna. Originally part of the Australian landmass, the highlands of Papua have a number of unique environments, including over six hundred bird species, with fauna closely related to that of Australia.

Regional Variations

The British naturalist Alfred Wallace described a dividing line between the distribution of Indonesia's Asian and Australasian species. Known as the 'Wallace Line', it runs roughly north-south along the edge of the Sunda shelf, between Kalimantan and Sulawesi, and then down along the deep Lombok Strait, between Lombok and Bali. West of the line the flora and fauna are more Asian; moving east from Lombok, they are increasingly Australian. Wallace described not only this transition between Asian and Australasian species, but also numerous species unique to the surrounding area, now termed 'Wallacea'.

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 endangered 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.

Mammals

Sundaland has a total of 381 mammal species. 173 of them are endemic to this region. Most of these species are currently endangered. Two species of orangutans, Pongo pygmaeus (Borneo orangutans) and Pongo abelii (Sumatran orangutans ) are listed in the IUCN red list. Other famous mammals, such as the Borneo proboscis monkey (Nasalis larvatus), the Sumatran rhinoceros (Dicerorhinus sumatrensis) and the Javan rhinoceros (Rhinoceros sondaicus) are also seriously threatened.

Birds

According to the Conservation International, a total of 771 bird species occur regularly in Sundaland. 146 of them are endemic to this region. Java and Bali have at least 20 endemic species, including the Bali starling (Leucopsar rothschildi) and the Javan plover (Charadrius javanicus).

Fish

Nearly 200 new species of fish have been discovered in the last ten years in this region, and around 1000 species of fish are currently known, lives in the rivers, lakes, and swamps of Sundaland. Borneo has about 430 species, with 164 of them are endemic. Sumatra has 270 species, 42 of them are endemic. The well-known golden arowana (Scleropages formosus) is one of the best examples for the fish of this region.

Amphibians and Reptiles

An astonishing 449 species in 125 genera of reptiles are estimated to live in Sundaland. 249 species of them and 24 genera are endemic. Three reptile families are also endemic to this region: Anomochilidae, Xenophidiidae and Lanthanotidae, the last represented by the Bornean earless monitor (Lanthanotus borneensis), a very rare and little-known lizard. Around 242 species of amphibians in 41 genera live in this region. 172 species of them, including the Caecilian and six genera are endemic.

Wallacea

The Wallacea represents the biogeographical transitional zone between the Sundaland to the west and the Australasian zone to the east. This zone covers of about 338 494 sq km land area in total, divided in multiple small islands. The large island of Sulawesi, the Mollucas and part of the Nusa Tenggara belong to this region. Due to its geographical factors, this region consist many endemic and unique species of fauna.

Mammals

The Wallacea has a total of 223 native mammal species. 126 of them are endemic to this region. An astonishing 124 bat species can be found in this area. Sulawesi, as the biggest island in this region, has the highest number of mammals: 136 species, of which 82 are endemic. Remarkable species such as anoa (Bubalus depressicornis) and babirusa (Babyrousa babyrussa) live on this island. At least seven species of macaques (Macaca spp.) and at least five species of tarsier (Tarsius spp.) are also unique to this island.

Birds

650 bird species can be found in Wallacea, of which 265 species are endemic. Among the 235 genera represented, 26 of them are endemic. 16 genera are restricted to Sulawesi and its surrounding islands. Approximately 356 species, including 96 endemic bird species live on the island of Sulawesi. One of them is the maleo (Macrocephalon maleo), a bird currently seen as endangered and found entirely within the Wallacea.

Fish

There are about 310 species of fishes recorded from the rivers and lakes of Wallacea; 75 species of them are endemic. Although little is still known about the fish of the Moluccas and the Lesser Sunda Islands, 6 species are recorded as endemic. On Sulawesi, there are 69 known species, of which 53 are endemic. The Malili lakes in South Sulawesi, with its complex of deep lakes, rapids and rivers, have at least 15 endemic telmatherinid fish, two of them representing endemic genera, three endemic Oryzias, two endemic halfbeaks, and seven endemic gobies.

Amphibians and Reptiles

With 222 species, of which 99 are endemic, the Wallacea has high reptile diversity. Among these are 118 lizard species, of which 60 are endemic; 98 snake species, of which 37 are endemic; five turtle species, two of them are endemic; and one crocodile species, the Indo-Pacific crocodile (Crocodylus porosus). Three endemic genera of snake can be found only in this region: Calamorhabdium, Rabdion, and Cyclotyphlops.

One of the most famous reptile in the Wallacea is probably the Komodo dragon (Varanus komodoensis), known only from the islands of Komodo, Padar, Rinca, and the western end of Flores.

58 native species of amphibians can be found in Wallacea, of which 32 are endemic. These represent a fascinating combination of Indo-Malayan and Australasian frog elements.

Invertebrates

There are about 82 species of birdwing butterflies recorded in Wallacea, 44 of them are endemic. 109 tiger beetle species are also recorded within this region, 79 of which are endemic. One of the most astonishing species is perhaps the world's largest bee (Chalicodoma pluto) in the northern Moluccas, an insect in which the females can grow up to four centimetres in length. This bee species nests communally in inhabited termite nests in lowland forest trees.

About 50 endemic mollusks, three endemic crab species, and a number of endemic shrimp species are also known from the Wallacea.

Environmental Issues

As a highly populous country part-way through a rapid industrialisation process, Indonesia faces grave ecological issues, which are often given a lower priority due to high poverty levels and under-resourced governance. Issues include:

• large-scale deforestation (much of it illegal) and related wildfires causing heavy smog over parts of western Indonesia, Malaysia and Singapore
• over-exploitation of marine resources
• environmental problems associated with rapid urbanization and economic development, such as air pollution, traffic congestion, refuse management, and reliable water and waste water services

Although 45% of Indonesian region is still inhabited and covered by tropical forests, high growth of Indonesian population, with its industrialisation, has slowly affected the existence of fauna in Indonesia. 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. As of 2003, The World Conservation Union lists as endangered 147 mammals, 114 birds, 91 fish and 2 invertebrate species.