This BioProvince (as defined by Armen Takhtajan) comprises the island of Sulawesi (Celebes) and its neighbouring islands. The physical history of eastern Indonesia has made it one of the most geologically complex regions of the World. A widely accepted view is that this zone represents the main point of ‘collision’ between the northern supercontinent of Laurasia and the southern supercontinent of Gondwanaland and that western Sulawesi had been part of Laurasia and eastern Sulawesi part of Gondwanaland. The geological history of the island, however, is now thought to be more complex than this and, in fact, Sulawesi can be divided into three distinct geological zones. East Sulawesi mainly consists of basic and ultrabasic igneous rocks associated with Mesozoic limestones in places. West Sulawesi has a basement of schists (metamorphic rocks of continental origin) and ultrabasic rocks overlain by marine sediments including limestone and sandstone, while the Bangyai-Sula island compex to the west consists of Palaeozoic metamorphic rocks intruded by granites. In addition, Sulawesi has eleven active volcanoes associated with a subduction zone north of Tolitoli. The most devastating eruption of recent times was that of the Colo Volcano on Una-una Island in Tomini Bay in 1983. Most of the island was blown apart destroying most of the vegetation but fortunately all of the inhabitants had been evacuated. Straddling the equator this BioProvince has a more or less constant temperature throughout the year but other climatic variables such as wind velocity, evaporation and humidity show considerable variation from place to place. The southeasterly winds from the dry Australian landmass causes a distinct dry season in the southwest peninsula and also causes a degree of seasonality in other parts. The flora comprises over 4200 species covering some 540 genera. There are many endemic species and a number of endemic genera such as Kalappia (Fabaceae). There is no clear affinity with the floras of islands east or west of Sulawesi although the lowland flora and the flora associated with ultrabasic rocks has some similarity with New Guinea but the montane flora seems to be closer to the flora of Borneo.
The following accounts for this BioProvince have been written or will be written with particular reference to endemic and locally important species. Accounts available are displayed in green or yellow. Those displayed in red are either in the pipeline or awaiting expert contributions.
|Endemic Vascular Plant Flora|