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This ecoregion represents these montane forests above 1,000 m, whereas the lowlands constitute a separate ecoregion. Most of Sulawesi lies above 500 m, and about 20 percent of the total land area-mostly the central region-is above 1,000 m (Whitten et al. 1987). Based on the Köppen climate zone system, this ecoregion falls in the tropical wet climate zone (National Geographic Society 1999). As might be surmised from its shape, Sulawesi has a complex geologic history and is composed of three geologic provinces based on that history. West and East Sulawesi form two of the geologic provinces, separated by the Palu-Koro fault, which runs from the town of Palu to the Gulf of Bone. The third geologic province consists of the Tokala region on the northeast peninsula, the Banggai Islands, Butung Island, and the Sula Islands. East and West Sulawesi collided approximately 13-19 million years ago, and ultrabasic rocks were exposed as East Sulawesi overrode the western portion. The forces that caused the collision are still at work, and Sulawesi is being torn apart today. The surface geology of Sulawesi is a diverse patchwork of ophiolites, Mesozoic sedimentary rocks, Tertiary sedimentary and igneous rocks, and Quaternary volcanics and sediments. Active volcanoes are located on the northern arm of Sulawesi (Whitten et al. 1987). Above 1,000 m, forest trees become shorter and less massive, and epiphytes such as orchids become more common. Whereas the forests of Sulawesi's lowlands are not dominated by any particular tree family, the forests in the lower montane region are dominated by oaks (four species of Lithocarpus) and chestnut (two species of Castanopsis). An example association includes Phyllocladus, Agathis dammara, and Eugenia dominated by Castanopsis. Upper montane forest contains conifers (pines and related Gymnosperms such as Podocarpus spp., Dacrycarpus spp., Dacrydium spp., Phyllocladus spp.) and the magnificent and commercially important Agathis spp. (Whitten et al. 1987). The highest peaks have sub-alpine forests with yet smaller trees whose branches bear epiphytic lichens and a ground cover of shrubs, colorful herbs, and grasses (Whitten et al. 1987).
Wallace's Line, running from between Bali and Lombok and between Sulawesia and Borneo, marks the location of a deep oceanic trench and the point over which land animals and plants could not cross easily. Similarly, Lydekker's Line, running from between Timor and the Australian shelf to between Halmahera, Seram, and New Guinea, marks the point where Australasian flora and fauna could not easily pass. Sulawesi lies between these two lines. Sulawesi's location, geologic history, and long geographic isolation have created Sulawesi's distinctive fauna. There is variability, different among various animal and plant groups, in the amount of interchange between other biogeographic areas in the region, which led to the evolution of a large number of species endemic to the island. Although not species-rich relative to Borneo or Java, Sulawesi is high in endemicity because of its long isolation from Asia and Australia in Wallacea. This ecoregion exhibits high plant endemism, and the several distinct forest types provide habitat for the highest number of endemic mammals in Asia and several endemic birds (Whitten et al. 1987). The ecoregion harbors 102 mammal species, of which 33 species are endemic or near endemic (table 1). Together with the lowland forests, the montane forests of Sulawesi have the highest recorded number of endemic mammals among the Indo-Pacific ecoregions. These endemic species include the endangered mountain anoa (Bubalus quarlesi) and crested macaque (Macaca nigra) and the vulnerable babirusa (Babyrousa babyrussa) and Sulawesi montane long-nosed squirrel (Hyosciurus heinrichi) (Flannery 1995; IUCN 2000). Table 1. Endemic and Near-Endemic Mammal Species.
There are approximately 168 bird species listed as resident in the ecoregion, of which 44 species are endemic or near endemic (table 2). The ecoregion also overlaps the montane portions of the Sulawesi EBA (Stattersfield et al. 1998). Of the fifty-four restricted-range bird species found in the EBA, fourteen species are found in both lowland and montane Sulawesi, and twenty-two species are only found in the uplands of Sulawesi. Nineteen of these montane species are found nowhere else on Earth. Two montane bird species are classified as threatened: the endangered Lompobattang flycatcher (Ficedula bonthaina) and the vulnerable Matinan flycatcher (Cyornis sanfordi) (Stattersfield et al. 1998). Table 2. Endemic and Near-Endemic Bird Species.
Two Centres of Plant Diversity are found in the uplands of Sulwesi: Dumoga-Bone National Park and Pegunungan Latimojong. The montane forests of Dumoga-Bone National Park contain a rich gene pool of timber trees and rattans and are dominated by Eugenia, Shorea, and Agathis, with an abundance of rattans in the understory. The lower montane forests of Pegunungan Latimojong and contain Lithocarpus, Phyllocladus hypophyllus, Podocarpus steupi, and Taxus sumatrana, whereas the upper montane areas contain Vaccinium and Rhododendron vanvuurenii, Hypericum leschenaultii, and Drimys piperata. The area extends to 3,455 m and contains extensive sub-alpine vegetation above 3,200 m (Davis et al. 1995).  Current Status
This ecoregion is still largely intact, with about three-quarters of the original habitat remaining. Most of the habitat destruction has occurred in the southwestern portion, and large blocks of forest remain in the northern and eastern montane areas of the island. The twenty-nine protected areas cover 23 percent of the ecoregion (table 3). The average size of a protected area in this ecoregion is 602 km2, and there are five protected areas that exceed 1,000 km2. Table 3. WCMC (1997) Protected Areas That Overlap with the Ecoregion.
The steep slopes and the relative lack of commercially valuable tree species help to discourage logging activity. However, the logging that has occurred has had devastating effects on the landscape and the ecosystems; for instance, extensive erosion on surrounding deforested slopes has clogged the irrigation systems of the once fertile rice fields of Palu Valley (Whitten et al. 1987). Hunting and anthropogenic fires are also serious threats to the wildlife assemblages and habitat. Hunters set fires to facilitate hunting of anoa, creating montane meadows. Upper montane and sub-alpine forests are subject to periods of drought, during which the oil-rich leaves of Rhododendron, Vaccinium, and Gaultheria easily catch fire. With repeated burning, alang-alang grass (Imperata cylindrica) may become dominant. Other threats include transmigration and local clearance (Whitten et al. 1987).
There have been several attempts to divide the bioregion into biogeographic units (MacKinnon 1997; Stattersfield et al. 1998; van Balgooy 1971, cited in Monk et al. 1997; MacKinnon and Artha 1981; MacKinnon and MacKinnon 1986; MacKinnon et al. 1982; van Steenis 1950; Udvardy 1975). Because many of the islands have distinct natural faunal communities and a high degree of endemism (Monk et al. 1997), the more recent attempts have used faunal dissimilarities-especially birds-to identify distinct biogeographic units (MacKinnon 1997; Stattersfield et al. 1998; MacKinnon and Artha 1981; MacKinnon and MacKinnon 1986). Because detailed floral data are largely unavailable across most of the bioregion, we followed these authors in delineating ecoregions based on distribution of biomes and vertebrate communities. On Sulawesi island we delineated two ecoregions: the Sulawesi Lowland Rain Forests [AA0123] and Sulawesi Montane Rain Forests [AA0124]. These represent the tropical lowland and montane tropical moist forests, respectively. The small patches of monsoon forests on the southwest peninsula of Sulawesi and on Butung Island (Whitmore 1984) were included in the Sulawesi Lowland Rain Forests [AA0123] but should be considered a distinct habitat type in an ecoregion-based conservation assessment to ensure representation.
References for this ecoregion are currently consolidated in one document for the entire Indo-Pacific realm. Reviewed by: This text was originally published in the book Terrestrial ecoregions of the Indo-Pacific: a conservation assessment from Island Press. This assessment offers an in-depth analysis of the biodiversity and conservation status of the Indo-Pacific's ecoregions. For more general information on this ecoregion, go to the WildWorld version of this description. All text by World Wildlife Fund © 2001 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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