Sundaland

Tony Whitten⁶⁹, Peter Paul van Dijk⁷¹, Lisa Curran⁴⁵, Erik Meijaard⁴⁶, Peter Wood⁷⁰, Jatna Supriatna⁴⁴ and Susie Ellis¹

The Sundaland Hotspot covers the western half of the Indo-Malayan archipelago (1.5 million km²), an arc of some 17 000 islands lying north and south of the equator and spanning a distance of 5 000 km between the Asian mainland and Australia. The hotspot is dominated by Borneo (725 500 km²) and Sumatra (427 300 km²), the third and sixth largest islands on Earth, with the remainder mostly occupied by the Malay Peninsula and the island of Java (126 700 km²). Sundaland sits on the Sunda Shelf, an extension of the Asian continent where the sea is shallow, 120 m deep or less, although the sea level has risen and fallen on several occasions during the past. As a result, for long periods of time, the islands of Sundaland were an extension of the Asian continental landmass, which is why the fauna and flora have much in common and why the Malay Peninsula is considered as part of this hotspot.

The hotspot is bordered by three other hotspots. The boundary between the Sundaland Hotspot and the Indo-Burma Hotspot to the northwest is here taken as the Kangar-Pattani Line, which lies near the Thailand-Malaysia border (Van Steenis 1950; Whitmore 1984). Wallacea lies immediately to the east of the Sundaland Hotspot, separated by the famous Wallace's Line, while the 7 100 islands of the Philippines Hotspot lie immediately to the northeast.

In political terms, Sundaland covers a small portion of southern Thailand (provinces of Pattani, Yala, and Narathiwat) south of the Kangar-Pattani Line; nearly all of the megadiversity country of Malaysia (most of Peninsular Malaysia and the East Malaysian states of Sarawak and Sabah in northern Borneo); Singapore at the tip of the Malay Peninsula; all of Brunei; and all of the western half of the megadiversity country of Indonesia, including the Indonesian portion of Borneo, Sumatra, Java, and Bali, and the many other smaller islands that are part of western Indonesia (e.g., the Bunguran group or Natuna Islands). The Nicobar Islands, which are jurisdictionally controlled by India, form part of this hotspot (having floristic affinities with this hotspot; Davis et al. 1995). The Cocos (Keeling) and Christmas Islands are also included, although both are oceanic islands that are politically part of Australia.

Sundaland shows tremendous variation in vegetation, with formations differing along bedrock, drainage, and altitudinal gradients (from sea level to 4 101 m). At lower altitudes, lowland rainforest occurs, and along sandy and rocky coasts, stands of beach forest can be found, while along muddy shores there grow stilt-rooted and other types of mangrove trees. Behind the mangroves in coastal Borneo and eastern Sumatra are large areas of peat swamp forest where the depth of the peat can exceed 20 m. In natural raised ridges and depressions, alluvial bench forests and freshwater swamps occur with just a thin layer of peat above the mineral soil, but these forest formations have been favored for agricultural use and are now rare.

Limestone habitats are widespread, but geographically isolated; these limestone formations have high levels of endemism, and exhibit high levels of alphaand beta-diversity of their associated flora and fauna. For example, the slipper orchid (Paphiopedilum sanderianum) is a beautiful species with corkscrew petals up to one meter long, and is known only from two small populations in the limestone hills of Gunung Mulu National Park, Sarawak (Whitten 2002).

On the slopes, one encounters montane forest in which the limbs of the trees are often swathed with a thick growth of moss, hanging garlands of lichens, and many exquisite orchids. Still higher up is the scrubby, but often colorful subalpine forest dominated by rhododendrons and their relatives. And, finally, one arrives at the bare exposed peaks of the higher mountains, with Mt. Kinabalu (4 101 m) on Borneo being the highest of all, and harboring a remarkable concentration of endemic animals and especially plants.

In terms of vascular plant diversity and endemism, no truly reliable estimates exist. However, by extrapolating from what is known of the principal islands and countries that comprise the hotspot, total vascular plant diversity is estimated at roughly 25 000 species, and the number of endemics at 15 000. In terms of higher-level plant endemism, there is just one endemic family, the Scyphostegiaceae, represented by a single species of tree, and at least 117 endemic plant genera. Borneo leads in endemic genera with 59, Sumatra has 17, and Java none, but the Malay Peninsula has 41. Borneo also has some 3 000 species of trees, including 267 species of the economically important Dipterocarpaceae, of which fully 155 (58%) are endemic to the island; Borneo also has over 2 000 species of orchids. Sundaland's flora includes several spectacular species, most notably Rafflesia, the best botanical flagship for the lowland forests, particularly Rafflesia arnoldii, whose one-meter “petals” make it the largest flower in the world.

Looking at vertebrate diversity, Sundaland has a total of 381 mammal species, of which 173 are endemic (27 to Borneo); in addition, 17 of the 136 genera present are endemic. Many of the mammals occurring in Sundaland are globally recognized flagship species, foremost of which are the two species of orang-utan, the Bornean (Pongo pygmaeus, EN) and the Sumatran (P. abelii, CR), both seriously threatened by habitat loss and hunting (Rijksen and Meijaard 1999). Other famous mammal flagships include the proboscis monkey (Nasalis larvatus, EN), also endemic to the island of Borneo, and the Sumatran rhinoceros (Dicerorhinus sumatrensis, CR) and Javan rhinoceros (Rhinoceros sondaicus, CR), the latter with only some 40-50 individuals left in the world. Also of special note are the four Mentawai Islands off the west coast of Sumatra (Siberut, Sipora, North Pagai, and South Pagai). These small islands, covering only 5 951 km², are home to fully four endemic species and seven endemic taxa of primates, including the endemic genus Simias, the pig-tailed langur.

A total of 771 bird species are thought to occur regularly in Sundaland, and no less than 146 are endemic. There are at least 30 endemic species on Borneo, most of which are montane species and, as such, the Bornean Mountains are considered one of five Endemic Bird Areas (EBAs) recognized by BirdLife International (Stattersfield et al. 1998) for this hotspot, in addition to Sumatra and Peninsular Malaysia, with 20 species confined to this EBA; Enggano (two species); the Java and Bali Forests (20 species, including the Bali starling, Leucopsar rothschildi; CR); and the Javan Coastal Zone (Javan plover, Charadrius javanicus).

Reptile diversity is estimated at some 449 species in 125 genera, of which 249 species and 24 genera are endemic. There are also three endemic reptile families, Anomochilidae and Xenophidiidae (two families of snakes, each with a single genus with two species each) and the monotypic Lanthanotidae, represented by the Bornean earless monitor (Lanthanotus borneensis), a very rare and little-known lizard. Amphibian diversity is also impressive, with around 242 species in some 41 genera, of which 172 species (including 14 species of caecilians) and six genera are endemic.

New species of fish are still being discovered in the rivers, lakes, and swamps of the area, nearly 200 in the last ten years alone. Currently, around 1 000 species are known (and as many as 1 400 projected) from Sundaland, of which 280 are restricted to one or more of the main islands. Yet again, Borneo boasts the most species, about 430, with 164 endemic, while Sumatra has 270 species, 42 endemic (Kottelat and Whitten 1996). The best flagship for the fresh waters of Sundaland is the dramatic Asian bony tongue or golden arowana (Scleropages formosus, EN), a very highly prized aquarium fish, with prices for large individuals reaching thousands of dollars.

Forest destruction rates as the major threat to the biodiversity of Sundaland. The vast majority of forest loss has occurred over the last 30 years or so, mainly as the result of commercial logging, followed by massive agricultural projects (e.g., rubber, oil palm, industrial timber for pulp production, etc.) and smallholder agriculture. The infamous Indonesian program of transmigration, in which people from Java and neighboring islands were translocated to other less densely inhabited parts of the country, also had a major impact, as has civil war in areas such as Nangroe Aceh, Darussalam Province, which has caused large numbers of refugees to move into North Sumatra Province.

A forest cover mapping effort conducted in 1999 by the Indonesian government with support from the World Bank concluded that the average annual deforestation rate between 1985 and 1997 in Indonesia was about 1.7 million ha, with Sumatra and Kalimantan both losing more than 20% of their forest cover. Around 35% of Sumatra and 60% of Kalimantan was considered forested in 1997, although these regions have experienced continued and accelerating declines. Particularly hard hit have been the more accessible lowland forests, with both islands having estimated losses of more than 60% between 1985 and 1997. More recent estimates indicate that Kalimantan's protected lowland forests declined by 56% between 1985 and 2001 primarily from logging ((Curran et al. 2004), and that less than 33% of lowland forest and peat swamp remains across all of Indonesian Borneo (L. Curran, unpubl.), although montane forest appears intact. Logging has also taken place within protected areas; for example, forest loss within Bukit Barisan Selatan National Park between 1985 and 1999 averaged around 2% per year (Kinnaird et al. 2003) and as much as 9.5% per year in Gunung Palung National Park between 1999 and 2002 (Curran et al. 2004). Some protected areas, such as Kutai National Park, have been completely deforested through a combination of the effects of logging, and also drought and fires associated with the 1982-1983 and later 1997-1998 El Niño phenomenon (see, for example, Siegert et al. 2001).

At current deforestation rates, lowland forest in Sumatra will disappear by about 2005 and in Kalimantan soon after 2010 (The World Bank, 2001; FWI/GFW, 2002; and see Wikramanayake et al. 2002). At the time of press, Malaysia is considering raising the upperaltitude ban on logging from 300 to 800 m altitude on the Peninsula.

Examining the region as a whole, some 700 000 km² of forest still remains, but highly fragmented, with many of these patches too small to support the full complement of species over the long term, and most in less accessible montane regions rather than in the speciesrich lowland forests. For example, a recent study of mass extinctions in Singapore in relation to habitat loss (which has exceeded 95% over 183 years) has revealed that forest reserves comprising only 0.25% of Singapore's 540 km² of original vegetation now harbor over 50% of the residual native biodiversity (Brook et al. 2003). Of the remaining forest, only about 100 000 km² can be considered more or less pristine. This accounts for only 6.7% of the original extent of this hotspot, with the bulk of this pristine forest being found in the interior portions of Borneo and in key protected areas in Sumatra and Peninsular Malaysia, although many of these comprise montane rather than lowland forests.

Currently, the World Database on Protected Areas reveals that protected areas cover about 12% of the land area of the hotspot. However, throughout Sundaland, the tendency is for the least threatened, least utilized, and least valuable habitats (such as upper montane forest) to be the best protected. Furthermore, protection of parks and reserves is highly variable, with some such as Taman Negara in Peninsular Malaysia, Kinabalu in Sabah, and Ujung Kulon and Gunung Gede Pangrango in Java being well protected, while others are still subjected to a variety of pressures including legal and illegal timber extraction. Indeed, less than half of the protected areas (representing a coverage of 5% of the hotspot) are classified in IUCN categories I to IV.

Given the pressures, special efforts and new approaches are needed for long-term and effective conservation in this hotspot. An interesting development on Borneo is the implementation of transboundary conservation areas or “peace parks.” For example, the Lanjak-Entimau Wildlife Sanctuary in Sarawak (168 758 ha) is contiguous with Batang Ai National Park (24 040 ha), also in Sarawak, and Betung Kerihun National Park (800 000 ha) in West Kalimantan. This is one of the largest contiguous areas of forest remaining in Indonesian Borneo, but it is under threat of illegal logging, while hunting for protected species is common. Other important clusters are Ulu Muda Forest Reserve, Hala-Bala Wildlife Sanctuary, Belum National Park, and Temengor Forest Reserve between Malaysia and Thailand. Initiatives are also under way to expand existing incountry protected area networks; for example, in the Tesso Nilo/Bukit Tigapuluh landscape in central Sumatra, the Critical Ecosystem Partnership Fund is supporting acorridor-level initiative to link four existing protected areas and one new protected area into a 3-million-ha haven of lowland forest. Such collaborative conservation efforts increase the effective size of protected areas to a great extent, but can only be effective in the long term if management strategies deal with the socio-economic and political drivers of land-use change.

In Indonesia, a new and encouraging policy initiative by the central government aims to reduce the number of existing logging forest concessions to half. Some cancelled or abandoned concessions have been converted to protected areas (for example, the Sebangau area in Central Kalimantan) while others will be designed for sustainable forest harvesting programs. In addition, a new policy framework allows for declaration of a protected area by local government officials, rather than by a process initiated by the national government. This model, being used to create new protected areas such as the Batang Gadis National Park in Sumatra, is particularly important because the impetus comes from local stakeholders who already support the Park's establishment and who feel a sense of ownership in the process, rather than a protected status imposed by the national government without consultation.

BirdLife Indonesia and other members of the Bird-Life International network are pursuing another novel initiative to acquire the rights to manage a logging concession in central Sumatra for conservation and rehabilitation. The approach is an important test of the effectiveness and cost-efficiency of an alternative to conventional protected areas, and will produce important lessons for management of the large areas of lowland forest in the hotspot, which are under logging licenses that will expire over the next decade.

Although this hotspot, one of the richest on Earth, still faces many serious problems, recent changes in the region, and especially in Indonesia, which has most of this hotspot within its borders, may bode well for the future. If biodiversity can be identified as a top priority and integrated into the policies of the government, much could be accomplished. However, making this possible will require a far greater effort on the part of everyone, from civil societies in these countries of Sundaland to the military and new political leadership that is taking hold under decentralization, with simultaneous increases in commitment and involvement from international donor agencies and conservation organizations alike. An indication of the changing interests in conservation in the region comes from Kerinci-Seblat National Park, which receives more than 200 requests from people interested in serving as volunteer rangers/interpreters every year– something that was unheard of only a few decades ago.

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