| The mechanisms regulating the taxonomic composition and relative abundance of taxa within biological systems are poorly understood. The diatoms of the ancient Malili Lakes (Sulawesi Island, Indonesia), however, provide an ideal system to quantify the relative importance of various mechanisms and selective processes, including geographic isolation, competition, selection, and physical limnology on the physical morphology and community characteristics of living organisms. In a quantitative examination of the floristics of the diatoms of the Malili Lakes, I evaluate the influences of geographic isolation and propagule pressure on the development of the diatom floras of the individual lakes. This floristic examination demonstrates that widely accepted stochastic models of diatom dispersal and colonization do not apply to the Malili Lakes and that the diatom floras of these lakes are regulated by mechanisms operating on the lake-to-lake, or within lake scale. In a subsequent taxonomic review of the genus Surirella, which contains descriptions of 11 taxa new to science, I demonstrate the morphological cohesiveness of the Surirella taxa of the Malili Lakes and evaluate the importance of physical limnology and novel morphological structures in the development and maintenance of highly endemic floras. |
