The wildlife of Indonesia is perhaps most widely known through the narrow but nonetheless spectacular lens of its charismatic/iconic species. There’s the familiar Sumatran tiger, Sumatran (and Bornean!) elephants, Javan and Sumatran rhinoceros, and the “man-of-the forest” orangutans of Borneo and Sumatra. There are sea turtles and crocodiles, king cobras and Komodo dragons. And don’t forget the magnificent fabled Papuan birds of paradise! Sadly many of these wonderful iconic species are threatened with extinction. But the story of Indonesia’s wildlife is much bigger than these species that have been made familiar to us through documentaries and conservation campaigns.
Bornean orangutan (Pongo pygmaeus); by greenhillsumatra.
Indonesia is one of the most biodiverse countries in the world. Depending on how biodiversity is expressed (for example, in numbers of species, in ecosystem variety, in terms of genetics, or using other parameters), Indonesia has always been recognized among the top countries (see Mongabay and Australian Government Biodiversity Theme Report). Recently many discoveries of species new to science, for example in the Foja Mountains (in the world’s third largest tropical wilderness – New Guinea), have further bolstered Indonesia’s biodiversity credentials.
Foja Mountains, Papua, Indonesia. Pristine montane tropical forest yielding many species new to science in recent expeditions. Photo by S Frazier.
In addition, Indonesia constitutes a large part of the Coral Triangle (a.k.a. the “Amazon of the seas”) – the global center of marine biodiversity. And at its heart, Indonesia’s Bird’s Head Peninsula (West Papua province) hosts an astonishing 72% of the world’s total coral species! Indonesia is now reckoned to support at least 20% of the earth’s total biodiversity, and is likely the most biodiverse place on the planet…at least for the present.
A nudibranch amidst a rich coral reef at Raja Ampat, the biodiversity “bull’s eye” of the Coral Triangle; by aldo.
What is it that has endowed Indonesia, a country that comprises just 1.3% of the world’s land surface, with its huge wealth of wildlife and flora? To begin to get a handle on this, one must look at Indonesia’s unique and complex biogeography including its island biogeography which has also made it host to many natural centers of endemism. The biogeography of Indonesia has been the product of the dynamic interplay of continental drift (more precisely, plate tectonics), volcanism and seismicity, land building and subsidence, sea level rise and fall, latitude, and the evolution spurred on by these and other processes and attributes, in repeating cycles of natural introductions (bridging and mixing) and isolation of species and biological communities, over millions of years.
Several biogeoraphic boundaries separating distinct faunal regions and eco-regions run through Indonesia. These have arisen due to the mentioned processes, the most familiar eco-zone boundary being the Wallace Line named after Alfred Russel Wallace, the famed British naturalist. Wallace wrote the “Malay Archipelago” about his exploration and research there, which included much of present day Indonesia. The Wallace line marks the southeastern edge of Asia (along the leading edge of the Sunda Shelf) and coincides with a transitional zone referred to as Wallacea (in Wallace’s honor), between the Asian fauna (known for its primates) and the Australian (Sahul) fauna (known for its marsupials). However another later described border, Weber’s Line to the east and running through the Tanimbar Islands group, is considered a more precise biogeographic boundary. Wallace independently conceived the theory of evolution through natural selection, along with Charles Darwin, which they jointly published in 1858.”
Map of Sunda and Sahul and the Wallace Line, the Lydekker Line and the Weber Line. (Author: Maximilian Dörrbecker)
Indonesia is an archipelago of over 17,500 mostly uninhabited islands, an “emerald necklace” stretching 5,400 kilometers (3,400 miles) from Sumatra and the Indian Ocean to the middle of New Guinea in the Pacific Ocean. This is a greater distance than the breadth of the continental US as is illustrated by this map. Amongst this vast expanse is a staggering diversity of topography and landforms (mountains, valleys, coral atolls, coastal plains, mighty rivers, etc) and ecosystems (lowland rainforests, peat swamps, wetlands, savannahs, montane cloud forests, mangroves, and more).
Indonesia’s island geography contrasts sharply with that of monolithic Brazil, the other country vying for the top biodiversity spot. However it is interesting to note that most of Indonesia’s land area (–land is just 16% of the country’s national territory) is concentrated in some rather large contiguous (is)land blocks. Within those thousands of islands are five of the world’s 15 largest islands (see previous map link): New Guinea (2nd largest; shared), Borneo (3rd; shared), Sumatra (6th), Sulawesi (11th) and Java (13th).
One aspect of Indonesia’s geographic situation that also contributes greatly to its role as a storehouse of global biodiversity is its tropical latitude. Of the 17 megadiverse countries identified in 1998 by Conservation International, all are located at least partially in the tropics. In general, the closer a country or region is to the Equator, the greater its biodiversity. Indonesia straddles the Equator with the major islands of Sumatra, Borneo and Sulawesi all crossed by it.
Let’s now take a look at a small sample of that amazing Indonesian biodiversity as depicted in wild spottings from Project Noah.
MAMMALS
A Sulawesi warty pig (Sus celebensis) and monitor lizard; by RonnyBuol.
Indonesia has more mammal species than any other country (515 species by most counts!). This is about 12% of the world total. Unfortunately about a third are threatened. See spottings of a bat, a monkey, a weasel, a possum and a deer.
BIRDS
A pair of Oriental pied hornbills (Anthracoceros albirostris); by Mona Pirih.
There are about 1539 bird species known to inhabit (about 430 endemic species) or visit Indonesia. This represents 17% of all bird species! See spottings of a stork, an egret an eagle, a duck, a shorebird, a dove, a cockatoo, a sunbird, and a finch.
HERPETOFAUNA
The world’s largest tree frog, a white-lipped tree frog (Litoria infrafrenata); by S Frazier.
Malaysian cat gecko (Aeluroscalabotes felinus); by KaraNorby.
Indonesia is home to about 16% of all reptile and amphibian species (about 781). See spottings of a common tree frog, golden tree frog, a toad, an agamid lizard, a monitor lizard, a turtle, a mangrove snake, a cobra, and a flying snake.
FISHES
A manta ray (Manta alfredi) swims in the highly biodiverse waters of Raja Ampat, West Papua; by CatalinIenci.
Information on the number of fish species in Indonesia is ambiguous among on-line sources but what is clear if that the Coral Triangle has more “coral reef fish species” than anywhere else in the world, hosting 37% (2,228) of the world’s 6,000 species. See spottings of a clown fish, an angler fish, a carpet shark, a moray eel, and a barracuda. There are only a couple for freshwater fish spottings for Indonesia in Project Noah, a panchax killifish and a blue-spotted mudskipper.
MARINE INVERTEBRATES
A cuttlefish from the seas around Bali, Indonesia, in the Coral Triangle; by ChrisP.
Arthropods and mollusks also contribute to the high biodiversity of Indonesia’s coral reefs. See a crustacean, flatworm and a nudibranch.
TERRESTRIAL ARTHROPODS
A spectacularly colored Eupholus sp. weevil from the forests of Papua; by S Frazier.
Indonesia is home to some 250,000 insect species, or 33% of the world’s total. Add to that the other arthropod classes and the number is even more mind-boggling! See a caterpillar, agrasshopper, a shield bug and a scorpion.
PLANTS
A New Guinea creeper (Mucuna nova-guineensis), one of several plants called “Flame of the Forest”, from Papua; by S Frazier.
There are about 28,000 species of flowering plants in Indonesia, including about 2,500 different orchids species, 122 species of bamboo, over 350 species of rattan and 400 species of Dipterocarpus hardwoods. Indonesia’s forests have a diversity of plants equaled only in Amazonia. See the world’s largest flower species, its tallest flower, an orchid, and mangroves.
FOOTNOTE
I think you’ll agree Indonesia supports an astonishing array of wildlife. And whereas this feature is meant to be a celebration of that huge natural bounty I would be remiss not to mention that this wealth has undergone, and continues to face, daunting challenges. Indonesia is a nation of 240 million people, with the 4th largest population in the world, situated on just 1.3% of its land area. Yet there are vast wild areas with relatively low population density. Nevertheless the greatest challenge faced by its terrestrial wildlife is illustrated by the fact that in a period of just 30 years, 80% of Indonesia’s forests have been lost to a number of factors especially conversion (e.g. to rubber, oil palm, and pulp plantations). This, of course, has ramifications for threatened species (like the tiger and orangutan, among many others) and climate change (carbon emissions from deforestation). In the east, Papua and West Papua provinces contain half or more of the world’s third largest tropical wilderness. As forests are depleted in other parts of the country pressure mounts on this eastern wilderness. But Indonesia from west to east is truly a repository of global biodiversity. Loss of this natural wealth including vital ecosystem services is a loss for us all.
Scott Frazier with special thanks to Mona Pirih and Jacob Gorneau.
References and Further Reading
Biodiversity in the Indo-Pacific Region