SPECIATION IN THE MALAY PENINSULA IN RELATION TO DIPTEROCARP FOREST HEIGHT, STRUCTURE, TURNOVER, AND REPRODUCTIVE BIOLOGY

The Malay Archipelago, also known as Malesia, is customarily divided into nine ecogeographical regions. In any comparison between these regions, Borneo usually stands out with the highest number of species, but if the number of species is divided by land area to obtain a regional species intensity index, the Malay Peninsula stands out prominently, not only for plants but also for mammals, reptiles, amphibians and fish. This striking pattern across the taxonomic spectrum suggests that the forces driving speciation have been more intense in the Malay Peninsula than in other regions of the Archipelago. The Malay Peninsula also stands out in comparison with countries in continental South- East Asia. Possible contributory factors to the intensity of speciation may be the height and structure of dipterocarp forests, the rate of tree turnover and the phenomenon of mass flowering.