Ecology of Sulawesi. Tony Whitten
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More recent geological history is reflected in the distribution of species within a particular genus. The most striking example of this allopatry (non-overlapping distribution of related species or subspecies) is perhaps the distribution of macaques. The number of species living on Sulawesi is the subject of some debate but four species and seven subspecies seems to be agreed by many (Groves 1980b). These macaques may have evolved from an ancestor of the pig-tailed macaque Macaca nemestrina (found now in Sumatra and Borneo), which crossed to Sulawesi, by rafting or by island hopping from Borneo or Java, possibly in the Middle Pleistocene (Fooden 1969; Takenaka 1982), but their origins and relationships have yet to be determined with certainty (Takenaka 1982; Takenaka and Brotoisworo 1982; Takenaka et al. 1985). It is interesting that M. maura in the southwest has the most primitive characteristics, and M. nigra living furthest away in Minahasa, is the most specialized (Albrecht 1977; Groves 1980b). The original condition was probably a single species but with 'clines' or gradients of character variations existing throughout the range. Disruptions to this continuous distribution would have caused populations to evolve in isolation such that when the disruption was removed the populations were reproductively incompatible (Fooden 1969).
During periods when the sea-level increased by only 4 m (p. 18) the mountainous region south of Lake Tempe would have been cut off by a narrow straits running northwest-southeast, and a narrow isthmus would have been formed between Gorontalo/Limboto and Kwandang. These inundations would help to explain the separation of M. maura and M. tonkeana, and of M. tonkeana and M. nigra. The junction of the two subspecies of M. tonkeana may have arisen from the formation of a narrow isthmus between Tamba and Labuhanbajo (near the prominent Tanjung Manimbaya), and the two subspecies of M. ochreata would have arisen because of the narrow straits between northern Buton and the southeast peninsula. It is not clear, however, how subspeciation arose between the two M. nigra subspecies, or speciation between M. tonkeana and M. ochreata, although unproductive forests on the ultrabasic soils (p. 457) may have formed a biological barrier in the latter case.
Other examples of allopatry are the distribution of subspecies of the large carpenter bee Xylocopa nobilis and of species of the large pond skater/water strider Ptilonera (fig. 1.33) although not enough specimens are known to be able to determine species boundaries.
Another example of closely-related species replacing each other geographically on Sulawesi is sometimes quoted, that concerning the white-eyes of lowland forests: Zosterops anomala in the southwest peninsula, Z. atrifrons in the north peninsula, the central block and Banggai Islands and Z. consobrinorum in the southeast peninsula (Stresemann 1939-41; Lack 1971). This distribution has now been shown to be rather less well-defined than was previously thought (Holmes and Holmes 1985).
Within a well-known group such as the birds, a number of interesting distribution patterns can be seen within those species endemic to the main island. For example, some species are known from only a single peninsula (table 1.14). Half of the 88 endemic birds are found in all regions of Sulawesi and half have partially-restricted distributions. Thus five species are known from only the north peninsula, central area and southeast peninsula, two from only the central area and southwest and southeast peninsulas, two from only the central area and southwest peninsula, etc. As a result the number of endemic species is different between the main areas (table 1.15). Some of these totals may change as more field data become available, particularly from the east peninsula, but they serve to illustrate the apparent paucity of the birds in the southwestern peninsula.
The Sula Islands, to the east of the Banggai Islands, are administratively part of the Moluccas but biogeographically they are part of Sulawesi. Of the birds, there are twice as many species with Sulawesi affinities as with Moluccan affinities (Wallace 1862) and the birds of the Banggai Islands seem to be derived almost equally from Sula and the mainland (Eck 1976). The reptile fauna of the Sula Islands is essentially a poor Sulawesi fauna (Kopstein 1927), and the flying lizards Draco of the Banggai Islands are more similar to those of the Sula Islands than to the mainland (Musters 1983).
From Holmes and Wood 1979; K.D. Bishop pers. comm.
From Holmes and Wood 1979
Figure 1.33. Distributions of the five known species of large pond skater/water strider Ptilonera on Sulawesi. Side views of terminal segments of females' abdomen illustrate the considerable morphological variation. Note the single zone of overlap, in Lore Lindu National Park, a - Ptilonera laelaps, b - P. sumizome, c - P. oribasus, d - P. pamphagus, e - P. dorceus.
After Polhemus and Polhemus 1986
PEOPLE OF SULAWESI
Prehistory
Remains of proto humans Homo erectus from about 500,000 to 1 million years ago have been found in Java but nothing similar has been found in eastern Indonesia. The first traces of modern man Homo sapiens in the latter area have been dated to about 30,000 years B.P.28 These were populations of hunter-gatherer people who were present throughout Indonesia and who successfully crossed the sea between New Guinea and Australia before 35,000 years B.P. They were the direct ancestors of the Australoids, found today in Australia and the New Guinea highlands, and relatives of some of the inland forest tribes of Peninsular Malaysia and the Philippines (Bellwood 1980a).
Between 4000 and 2000 B.C., Austronesian-speaking people on Taiwan and mainland eastern Asia, with an economy based on plant cultivation, began to spread through the Philippines into eastern Indonesia and western Melanesia (the islands of the Bismark, Solomon and New Caledonia groups). This expansion was perhaps initiated by agricultural developments in southern China and Taiwan, and had, by 1500A.D., reached over half the circumference of the globe from Madagascar (colonized from Indonesia) to Easter Island (Bellwood 1980a). The people had taken with them domestic pigs Sus scrofa and dogs, pottery, bows and arrows, a tradition of thatched community houses, fishing and canoe transport with sails. They cultivated taro, bananas, breadfruit, sugarcane,29 sago and possibly coconuts. These people did not replace indigenous inhabitants but rather blended with them (Jacob 1967; Bellwood 1985), and their technological and cultural novelties were adopted. Tracing the migration is extremely difficult because racial history is very complex and some human physical characteristics are easily changed.30
The early setters of South Sulawesi are known from remains excavated in many caves in the southern half of the province (Sarasin and Sarasin 1905; Mulvaney and Soejono 1970; Heekeren 1972) and the most detailed records, indeed among the most detailed in Southeast Asia, come from three caves near Maros (fig. 1.34) (Glover 1976, 1977, 1978, 1979a, b, 1981; Burleigh 1981; Frank 1981; Glover, E. 1981; Mook 1981; Vita-Finzi 1981). The caves, in order of artefact age are Leang Burung 2, Ulu Leang and Leang Burung 1 and represent the period between about 30,000 and 8000 years B.P.. although there is a gap of 10,000 years between Leang Burung 2 and Ulu Leang and overlap between Ulu Leang and Leang Burung 1 (Glover 1977). The culture whose remains are found is sometimes termed 'Toalean' after a tribe of hunter-gatherer and occasionally cave-dwelling people encountered by the Sarasins in the hills half-way between Maros and Watampone. Photos of these people were printed in their book (Sarasin and Sarasin 1905). To-ala means