Wallacea

Tony Whitten⁶⁹, Jatna Supriatna⁴⁴, Ria Saryanthi⁷⁰ and Peter Wood⁷⁰

Wallacea is the biogeographical name given to a region comprising thousands of islands lying between Java, Bali, and Borneo to the west and Papua to the east. The hotspot covers the central part of Indonesia and the whole of Timor Leste. It includes the large island of Sulawesi (178 700 km²), and the smaller islands of two extensive archipelagos: the Moluccas (or Maluku in Indonesian) and the Lesser Sundas (the Indonesian region of Nusa Tenggara and Timor Leste). In total, the land area of this region is around 338 494 km², and it is one of two hotspots found within Indonesia, the other being Sundaland to the west.

Wallacea is named after the great nineteenth-century English explorer-naturalist Alfred Russel Wallace, who found that the Indonesian Archipelago (then called the Malay Archipelago) was inhabited by two distinct faunas, one found in the east and one in the west, and proposed a line running between Borneo and Sulawesi and Bali and Lombok that separated these two faunas (Wallace 1876); this line has long been known as Wallace's Line, and the region between it and the island of New Guinea has come to be called Wallacea (e.g., Dickerson 1928). In certain ways, Wallacea is a transition zone between the great Indo-Malayan (or Oriental) and Australasian biogeographical realms, rather than a distinct biogeographical entity in itself; nonetheless, it has a fascinating and highly endemic fauna of its own.

In terms of natural vegetation, Sulawesi and the Moluccas are largely in a tropical rainforest zone, but in large parts of the Lesser Sundas, rainforest formations are found only at high elevations and in areas facing the rain-bearing winds, while significant areas are covered in savanna woodland, even including some Eucalyptus forests. The wetter lowland and hill forests have the highest number of tree species, but differ from the commercially valuable forests of Sundaland in having only a handful of dipterocarp species. The major trees of commercial value are the tall kauri (Agathis spp.), the magnificent yellow-flowered legume Pterocarpus indicus in the more seasonal areas, and the gum tree Eucalyptus deglupta, usually found in riverine habitats and used extensively in reforestation projects. In some lowland areas, such as in eastern Sulawesi, there are unusual and infertile ultrabasic soils with high concentrations of iron, magnesium, aluminum, and heavy metals. The lowland forests on these nutrient-poor ultrabasic soils have rather short trees, and appear to be dominated by the myrtle family. Animal life in ultrabasic forests is, in general, rather limited.

Biological data for Wallacea is patchy. There are fewer botanical specimens per-unit-area collected there than on any other major islands in Indonesia, for example, and the amphibians are poorly known. For other groups, species lists for islands may be near complete, but there is very little information on distribution or the impact of habitat loss except where conservation organizations (such as the Wildlife Conservation Society in Sulawesi) have worked intensively. The Moluccas, in particular, are lacking up-to-date information on the status of species and habitats.

Total vascular plant diversity in Wallacea is estimated at 10 000 species, of which perhaps 1 500 species are endemic; there are at least 500 species endemic to Sulawesi alone, 120 to the Lesser Sundas, and 300 to the Moluccas. There are also at least 12 endemic genera in the region, seven on Sulawesi, three in the Lesser Sundas, and two in the Moluccas.

In terms of vertebrate diversity, Wallacea has a total of 223 native mammal species, 126 of which are endemic. If the 124 bat species are excluded, 87 of the 99 non-flying mammals, or 88%, are endemic. Sulawesi has the highest number of mammals (136), of which 82 species and about one-quarter of the genera are endemic. The list of Sulawesi endemic mammals includes flagship species such as the anoa (Bubalus depressicornis, EN) – a dwarf buffalo – and babirusa (Babyrousa babyrussa, VU), an enigmatic pig with long, recurved upper tusks that penetrate through the skin of the upper lip. In addition, the primates of Sulawesi are all important flagship species, with at least seven species of macaques (Macaca spp.) unique to the island and at least five species of tarsier (Tarsius spp.).

There are 650 bird species in Wallacea, of which 265 species are endemic, again very high numbers given the land area of the region. Of the 235 genera represented, 26 are endemic, with 16 genera (15 of them monotypic) restricted to Sulawesi and its satellite islands. Sulawesi has the largest bird fauna, with 356 species, including 96 endemics, among them the maleo (Macrocephalon maleo, EN), a distinctive megapode currently thought to number between 4 000 and 7 000 breeding pairs. Ten Endemic Bird Areas (identified by BirdLife International) are found entirely within Wallacea (Stattersfield et al. 1998S), and BirdLife Indonesia has recently identified 112 Important Bird Areas (IBAs) – priority areas for avian conservation throughout the region – including 33 on Sulawesi, 36 in the Moluccas, and 43 in the Lesser Sundas (Rombang et al. 2002, in prep.).

Reptile diversity is also quite high, with 222 species, 99 of which are endemic. These include 118 lizards, with 60 endemics; 98 snakes, of which 37 are endemic; five turtles, two of them endemic; and one crocodilian, the wide-ranging saltwater or Indo-Pacific crocodile (Crocodylus porosus). There are also three endemic genera (all snakes): Calamorhabdium, with two species; and Rabdion and Cyclotyphlops, both monotypic. The best known reptile in Wallacea, and one of Indonesia's most famous species, is the Komodo dragon or ora (Varanus komodoensis, VU), the heaviest lizard in the world (males can reach about 2.8 m in length and weigh about 50 kg), known from only the tiny islands of Komodo, Padar, and Rinca, and the western end of Flores. Amphibians are represented by 58 native species, all of them frogs; of these, 32 are endemic. The frog fauna is a fascinating combination of Indo-Malayan and Australasian elements, with several local radiations as well.

With freshwater fishes, most of the 310 species recorded from the rivers and lakes of Wallacea are tolerant of both fresh and salt water to some extent. Around 75 species are endemic. In the Moluccas and Lesser Sundas, the fish fauna is poorly known, but there appear to be around six island endemics. On Sulawesi, however, there are 69 known species, of which 53 (77%) are endemic. The complex of deep lakes, rapids, and rivers which makes up the Malili Lakes in South Sulawesi has at least 15 endemic and quite beautiful telmatherinid fishes, two of them representing endemic genera, three endemic Oryzias, two endemic halfbeaks, and seven endemic gobies, as well as about 50 endemic mollusks, three endemic crabs, and a number of endemic shrimps.

The invertebrate fauna of Wallacea remains poorly known, except for groups such as the enormous birdwing butterflies (members of the swallowtail butterfly family). The birdwings are represented by 82 species in Wallacea, 44 of which are endemic. There are also 109 tiger beetle species recorded from this hotspot, 79 of which are endemic (D. Pearson, pers. comm.). Wallacea also has the world's largest bee (Chalocodoma pluto) in the northern Moluccas, a creature in which the females can grow to four centimeters in length. This bee is also remarkable because it nests communally in inhabited termite nests in lowland forest trees.

As elsewhere, things have changed dramatically in Wallacea during the course of the past century. The human population has nearly quadrupled, and the Indonesian economy has grown tremendously. In the last decade, one of the world's newest countries, Timor Leste, was created in the hotspot, and many parts of Wallacea have seen political turmoil and dramatic changes. The first commercial logging operation in Wallacea began in the early part of the century, and forests have been cleared for agricultural programs, for industrial timber plantations, and for land settlement schemes. Much of the remaining forest is allocated as timber concessions and other areas are threatened by mining developments. Furthermore, as has been so obvious with the El Niño-related fires that have raged through much of Indonesia from mid-1997 to the present, fire continues to be a problem – and is now greatly exacerbated by increased drying because of logging and plantation agriculture, and sometimes by intentional burning as well ((Brown 1998). Invasive alien species are a threat that is certainly widespread, but too little understood. Hunting and trapping for the pot, and the exotic pet trade, are widespread. Terrestrial and marine conservation issues can not be separated, as the livelihoods of a huge proportion of the region's human inhabitants come from the sea and are under pressure from overexploitation and pollution.

As a result of the different human impacts on the Sulawesi environment, there has been substantial decline in forest cover, although less than that in most of the other hotspots. What remains is also partly a function of dryness and altitude. Lowland areas have suffered more than the highlands and, while dry forest types in general have only about 10%-20% remaining, moist and wet forest types have substantially more. The Lesser Sundas are thought to have only about 7% forest cover remaining, while Sulawesi is still about 42% covered in original forest (FWI/GFW 2002). Overall, about 45% of Wallacea still has some forest cover; however, if one considers forest that is still in more or less pristine condition, the percentage drops to only 15%. This loss of forest habitat, particularly in the lowlands, has caused dramatic and severe declines in the populations of numerous forest species (many as much as 90%); as an example, Wallacea holds around 5% of the world's threatened birds.

At this point in time, forest protection in Wallacea is inadequate. For the hotspot as a whole, protected area coverage is around 24 387 km², or 7% of its original extent. Around 6% of the protected areas coverage is represented by reserves in IUCN categories I to IV. As an example of the poor representation of biodiversity in protected areas, only 35 of the 112 IBAs that have been identified are protected. Of course, establishment of protected areas is only a beginning. Once created, they need management and the cooperation of local people, the government, and the private sector in order to be successful in conserving biodiversity.

Although little known outside the region, Wallacea does have a number of interesting conservation stories. One of these is in the 3 000-km² Bogani Nani Wartabone (previously Dumoga Bone) National Park in northern Sulawesi, one of the most important conservation areas on the entire island. In the 1980s, the World Bank helped WWF to encourage establishment of this park for the purpose of protecting the upper watershed of the Dumoga River, which was to be used to irrigate 110 km² of rice fields. The park had support from provincial and district officials for many years, but recently has suffered from large numbers of smallscale gold miners, who have poisoned the river with mercury and have cleared forest. Agricultural encroachment and illegal logging, hunting, and rattan collection are also on the increase. Recently, the government of Gorontalo Province on Sulawesi increased the size of the Paguyaman Forest, the stronghold of the babirusa.

On Sulawesi, over the last nine years, Conservation International has been engaged in community-based conservation in the Togean Islands. The Togeans occupy the central portion of Tomini Bay, stretching over a distance of about 90 km. The main threats are overfishing and destructive fishing, as well as illegal logging and small plantation developments. Recently, the local government has declared its intention to proclaim the Togeans as a marine park for tourism, covering 4 000 km² of marine and terrestrial habitats.

The Wildlife Conservation Society (WCS) carried out a three-year island-wide biodiversity survey, covering eighteen forests, to understand the status of key wildlife species, their habitats, and the factors contributing to their distribution and abundance. Based on their findings, recommendations for conservation priorities will be made to governments at the national, provincial, and regional levels. WCS also assists the government in managing several protected areas throughout northern Sulawesi by providing technical assistance through wildlife monitoring, joint forest patrols, GIS analyses, helping to establish a formal collaborative management scheme, monitoring and increasing breeding success of maleo birds, and through the Wildlife Crimes Units, a collaborative program established to strengthen conservation law enforcement.

The Nature Conservancy is active in Komodo National Park, which covers 1 730 km², including 1 320 km² of coral reefs and sea at the eastern tip of Flores. Conservation activities have included awareness programs, the formation of a dive club and lodge which incorporates ecotourism training facilities, reaching agreement on how to allocate tourism revenues, capacity-building for communities and the conservation agency, and alternative livelihood programs to draw people away from overfishing, fuelwood collection, setting fires to promote grazing, and dynamiting reefs to catch fish.

On the Sangihe-Talaud Islands, between northern Sulawesi and the Phillipines, seven endemic bird species depend on two forest areas that are shrinking even though they are protected. BirdLife Indonesia and the World Bank-GEF have successfully promoted a process to resolve community-government conflicts that had prevented progress in forest conservation, and are now working with all parties concerned. BirdLife International and BirdLife Indonesia have worked together on Sumba Island in the Lesser Sundas for the past eight years. Two National Parks have been declared to protect the most important remaining forests on the island, disputes over community land inside the park have been resolved, and communities have started to take action to stop illegal logging and trapping inside the area. The program is working to formalize the role of local communities in management and protection of the park, and to set up a sustainable management system that involves all local stakeholders. BirdLife Indonesia has also undertaken surveys and identified priorities for action throughout the Lesser Sundas and the Moluccas. On Tanimbar Island in the southeast Moluccas, this has been followed up with a project to help local government and communities plan the management of their still-extensive forests (which are home to eight endemic bird species). On Halmahera, development of conservation action to protect the critical forests on the island was suspended with the violence in 1999 and has been revived in 2004.

Although Wallacea is still in relatively good shape compared to most other hotspots, much needs to be done to ensure that its large number of endemic species and unique ecosystems are maintained.

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