The large Indonesian island of Sulawesi and a few smaller associated islands constitute this EBA, which includes the provinces of Sulawesi Utara, Sulawesi Tengah, Sulawesi Selatan and Sulawesi Tenggara. Sulawesi is a curious shape, with a relatively small central portion from which four long peninsulas radiate. It is mountainous virtually throughout, with extensive montane areas above 1,000 m on all four peninsulas and in the centre of the island, and few extensive low-lying areas. The highest peak, Mt Rantemario, rises to 3,455 m.

Sulawesi experiences high temperatures and rainfall throughout the year, and the natural vegetation in most parts of the island is tropical lowland evergreen or semi-evergreen rain forest below about 1,000 m, tropical lower montane rain forest between about 1,000 and 2,100 m, and tropical upper montane rain forest between about 2,100 and 3,250 m. The boundary between lowland and montane habitats is represented on the map by the 1,000 m contour. There are some extensive areas of forest on ultrabasic soils on the east and south-east peninsulas and forest on limestone in many parts of the island. Monsoon forest is found in a few parts of the EBA, for example near the tip of the south-east peninsula (Whitmore 1984, Whitten et al. 1987c).

Sulawesi has a relatively depauperate avifauna, with about 120 fewer species than the smaller island of Java, but a high degree of endemism, a result of long isolation from continental landmasses (Watling 1983, Andrew 1992). The 42 restricted-range species which are endemic to this EBA include a remarkable total of 12 endemic genera: Macrocephalon, Aramidopsis, Cryptophaps, Meropogon, Cataponera, Geomalia, Heinrichia, Malia, Hylocitrea, Coracornis, Myza and Enodes, plus Cittura which only otherwise occurs on Sangihe (EBA 167). An additional 16 species of birds are endemic to the Sulawesi EBA (see White and Bruce 1986, Andrew 1992), but are not considered to have restricted ranges because they are widely distributed throughout the island and have been recorded in a relatively broad range of habitats, often in both the lowlands and the mountains.

Almost all of the restricted-range species are forest birds, and they are found at all altitudes on the island. Many of these species appear to be patchily distributed on Sulawesi; this is partly a result of uneven coverage by ornithologists, but also a reflection of local variations in forest type related to altitude, climate, soil and landform. Seventeen of the species are apparently restricted to the lowlands, and 23 are restricted to montane forest, which led to Sulawesi formerly being divided into a lowland and a montane EBA (ICBP 1992, Sujatnika et al. 1995). However, for consistency with similar situations elsewhere in the world, Sulawesi is treated in the present global analysis as a single EBA.

Several of the restricted-range species appear to be confined to certain parts of the EBA (see 'Distribution patterns' table). In some cases this may be related to the geological history of Sulawesi, which is believed to be the cause of local endemism within the island among the macaques Macaca spp. and some insect groups (Whitten et al. 1987c). However, it could also be the result of specialized habitat requirements or competitive exclusion (by other closely related species) or might simply reflect gaps in knowledge (as some parts of Sulawesi are very poorly worked by ornithologists, notably the east and south-east peninsulas). Eurostopodus diabolicus is only definitely known by the type-specimen, collected on the Minahassa peninsula, although there is a possible sighting from central Sulawesi (King 1994). Cyornis sanfordi is only recorded from the Minahassa peninsula, Prioniturus flavicans from this peninsula and the nearby islands, Zosterops consobrinorum from the south-east peninsula and Buton (Wardill 1995), Z. anomalus from the south peninsula and Ficedula bonthaina from montane forest on Mt Lompobattang in the south peninsula (which also supports several endemic subspecies of birds: P. Andrew in litt. 1992; see Fraser and Henson 1996). Other species known from only a handful of specimens and sight records are Tyto inexspectata, Aramidopsis plateni and Gymnocrex rosenbergii.

Large tracts of undisturbed forest remain on Sulawesi, and total forest cover is estimated to have been 56.4% in 1988 (RePPProT 1990, Collins et al. 1991), although since then some large areas of lowland forest have been cleared (A. J. Whitten in litt. 1993). The extinct volcanoes of the south peninsula, including Mt Lompobattang, have resulted in rich volcanic soils, so the lowlands in that part of the island are densely populated and largely deforested. Land clearance for transmigration settlements (and further illegal clearance by some of the settlers) and agricultural projects such as sugar-cane plantations, as well as unsustainable logging, have led to deforestation of the lowlands in many other parts of the EBA (Whitten et al. 1987c, Collins et al. 1991), so the group of restricted-range species which are found in lowland forest are under the most immediate pressure. Much of the remaining forest is in the hills and mountains, so the montane avifauna of Sulawesi is currently relatively secure.

Six of the restricted-range bird species are threatened, including three which appear to be rare and confined to the lowlands and are likely to be vulnerable to habitat loss, two montane species with particularly small ranges, and Macrocephalon maleo, which lays communally on beaches and in forest clearings and is vulnerable to disturbance at nesting sites and over-exploitation of its eggs, as well as habitat loss. The particularly poorly known Tyto inexspectata is treated as Data Deficient. A more widespread threatened species (found throughout much of Wallacea) which occurs in the EBA is Yellow-crested Cockatoo Cacatua sulphurea (classified as Endangered), which is declining throughout its range because of a combination of habitat loss and unsustainable levels of trapping for the bird trade (see Cahyadin et al. 1994, Wardill 1995).

There are gazetted protected areas in central Sulawesi and on all four peninsulas, including several large reserves such as Dumoga-Bone, Lore-Lindu and Rawa Aopa Watumohai National Parks and Morowali and Pegunungan Feruhumpenai Nature Reserves. Almost all of the restricted-range species have populations in at least one protected area. However, the following sites, mainly areas of undisturbed forest, have been proposed for protection in order to strengthen the network: Mamaju (which contains lowland and coastal forest), Pegunungan Latimojong, Gunung Lompobattang (the only known locality for Ficedula bonthaina), Pegunungan Buol Toli Toli, Gunung Sojol and Pegunungan Palu dan Sekitarnya. As a result of a PHPA/ICBP/WWF Maleo Conservation Project in 1990–1991, the following sites have been recommended to be gazetted to protect nesting grounds of Macrocephalon maleo: Bakiriang, Buntalo, Sangkup, Molobog, Torosik, Molonggota and Dehua (Tanjung Panjung) (FAO 1982b, Sujatnika and Jepson 1995).

Recommended citation
BirdLife International (2024) Endemic Bird Area factsheet: Sulawesi. Downloaded from https://datazone.birdlife.org/eba/factsheet/167 on 21/11/2024.