Processes regulating the community composition and relative abundance of taxa in the diatom communities of the Malili Lakes, Sulawesi Island, Indonesia

Although high levels of endemism have been reported on Sulawesi Island for almost 150 years, the aquatic systems of the island have received little attention until recently. The diatoms of the ancient Malili Lakes, located on central Sulawesi, exhibit levels of endemism unequaled elsewhere in the world. Interestingly, the diatom community of the lakes is taxonomically impoverished, and the entire order Centrales is conspicuous by its absence. In this article we review the mechanisms contributing to the development and maintenance of community composition and relative abundance of taxa within the system, at within-lake and system-wide scales. Our findings demonstrate that stochastic processes related to biogeography and colonization have had little influence on the diatom flora of the lakes, and deterministic processes related to competition, selection, speciation, and adaptive radiation, functioning on very small spatial scales, have contributed greatly to the diversity, community structure, and endemism of the system.