ABSTRACT
Southeast Asia is not a homogeneous biogeographical area. Situated at the contact between several tectonic plates, its paleogeographical history is probably the most complex and the least known among the large land masses of the world (Whitmore, 1987). Limestone rocks of various geological ages and extent are present up to the highest altitudes (Sulawesi: Mt Mekongga, 2800 m), representing all the classical karst types, from coral limestone to immense plateaux and cone karsts. An important feature controlling the diversification of cave fauna’ is habitat fragmentation. Southeast Asian karsts are extremely fragmented. Thousands of limestone islands are scattered from the Philippines to Indonesia, and a huge number of limestone outcrops exist inland in Java, Sumatra, Sulawesi, and Peninsular Malaysia. Climate is another influential factor for subterranean biodiversity. The region is mostly under an hyperhumid tropical climate, which is thought to hamper the evolutionary shift towards obligate subterranean life, but some parts of the region (in Laos, central and eastern Thailand, and parts of Java, Sulawesi, and Eastern Maluku) experience a relatively dry or seasonal climate.
