The flora in Indonesia consists of many unique varieties of tropical plants. Blessed with a tropical climate and around 18,000 islands, Indonesia is a nation with the second largest biodiversity in the world. The flora of Indonesia reflects an intermingling of Asian, Australian and the native species. This is due to the geography of Indonesia, located between two continents. The archipelago consists of a variety of regions from the tropical rain forests of the northern lowlands and the seasonal forests of the southern lowlands through the hill and mountain vegetation, to sub-alpine shrub vegetation. Having the second longest shoreline in the world, Indonesia also has many regions of swamps and coastal vegetation. Combined together, these all give rise to a huge vegetational biodiversity.
There are about 28,000 species of flowering plants in Indonesia, consisting 2,500 different kinds of orchids, 6,000 traditional medicinal plants used as jamu, 122 species of bamboo, over 350 species of rattan and 400 species of Dipterocarpus, including ebony, sandalwood and teakwood. Indonesia is also home to some unusual species such as carnivorous plants. One exceptional species is known as Rafflesia arnoldi, named after Sir Thomas Stamford Raffles and Dr. Arnold, who discovered the flower in the depths of Bengkulu, southwest Sumatra. This parasitic plant has a large flower, does not produce leaves and grow on a certain liana on the rain forest floor. Another unusual plant is Amorphophallus titanum from Sumatra. Numerous species of insect trapping pitcher plants can also be found in Borneo, Sumatra, and other islands of the Indonesian archipelago.
According to the Conservation International, there are two biodiversity hotspots in Indonesia: Wallacea and Sundaland. The provinces of West Papua and Papua are also extremely biodiverse. Lorentz National Park, located in the province of Papua, was declared a World Heritage Site in 1999 by UNESCO.
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 km² land area in total, divided in multiple small islands. Due to its distinct and varied geography this region contains many endemic and unique species of flora and fauna and has been divided into a number of distinct ecoregions; the mountain and lowland areas of Sulawesi, North Maluku, Buru and Seram in Maluku, the Lesser Sunda Islands (with Sumba a distinct ecoregion in its own right), Timor, and the islands in the Banda Sea.
Sundaland, which is located on the west part of the Indonesian archipelago, holds about 25,000 different species of plants. 15,000 of them are endemic to this region and cannot be found anywhere else. Scyphostegiaceae is a plant family represented by a single species, Scyphostegia borneensis, which is endemic to Borneo. Another 155 species of Dipterocarpus are also endemic to this island. Borneo also has more than 2,000 species of orchids. The forests in Sumatra include more than 100 species of Dipterocarpus, nearly a dozen of them are endemic to this island. The island Java has about 270 endemic orchid species.
At least 117 plant genera are endemic in this biodiversity hotspot. 59 of them are found in Borneo and 17 in Sumatra. Unique plants from this region are similar to ones from the Asian continent, mentioning Rafflesia arnoldii, the pitcher plants and Javanese Edelweiss (Anaphalis javanica) as examples.
It is estimated, that there are about 10,000 species of plants in this biodiversity hotspot region. The island of Sulawesi has about 500 endemic plant species. The islands of Moluccas have about 300 endemic plant species and the Lesser Sunda Islands consist of at least 120 endemic plant species. Little is known about the flora of this region. Three of these unique species, Agathis, Pterocarpus indicus, and Eucalyptus deglupta, are mentioned as examples.
West Papua and Papua
The flora of this region has somewhat the influence of the Australian continent. This region contain a continuous transect from snow cap mountains, lowland wetlands to tropical marine environment. This is the perfect place for such a huge number of diverse plant species. It has been estimated that Papua and west Papua may contain from 20,000 to 25,000 species of vascular plants. An astonishing 60-90% of them may be endemic to this region. This region has been poorly explored so the actual number of endemic species is unknown.
The fauna in Indonesia consists of a high level of biodiversity due to its vast-size and tropical archipelago make-up. Indonesia divides into two ecological regions; western Indonesia is more influenced by Asian fauna, and the east is more influenced by Australasian. The Wallace Line (Wallacea), notionally divides these two regions. 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.
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, Borneo and Sumatran orangutans are listed in the IUCN red list. Other famous mammals, such as the Borneo proboscis monkey, the Sumatran and the Javan rhinoceros are also seriously threatened.
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 and the Javan plover.
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, 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.
Nearly 200 new species are discovered in the last 10 years in this region. Around 1000 species of fishes are known to live in the rivers, lakes, and swamps of Sundaland. Borneo has about 430 species, with 164 of them considered endemic. Sumatra has 270 species, 42 of which are endemic. The well-known golden arowana is one of the best examples for the fishes of this region.
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 to be exact, of which 82 species and one-quarter of the genera are endemic. Remarkable species such as anoa and babirusa live on this island. At least seven species of macaques and at least five species of tarsier are also unique to this island.
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, a bird currently seen as endangered and found entirely within Wallacea.
With 222 species, of which 99 are endemic, 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. 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, 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.
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 fishes of the Moluccas and the Lesser Sunda Islands, six 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 fishes, two of them representing endemic genera, three endemic Oryzias, two endemic halfbeaks, and seven endemic gobies.
There are about 82 species of birdwing butterflies recorded in Wallacea, 44 of them are endemic. 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 in the northern Moluccas, an insect in which the females can grow up to four cm 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 Wallacea.
West Papua and Papua
The fauna of this region comprises a huge diversity of mammals, reptiles, birds, fishes, invertebrates and amphibians, many species of which are of Australasian origin. Ecoregions here include; the mountains of Bird’s Head Peninsula West Papua, the lowlands of West Papua and Papua, the Biak Islands, Yapen island, the lowlands of New Guinea’s northern coast, the mountain ranges behind the northern coast, medium and high elevations of the New Guinea Highlands, the lowlands and the swamplands of the southern coast, and finally areas of mangrove swamp scattered around the coast.