The Investigation of Saturation in the Species Richness of Communities: Some Comments on Methodology

A central task for ecologists is to explain the variation in local species diversity or richness. In order to know whether to invoke primarily local ecological or regional biogeographic explanations, it becomes necessary to discover whether communities are saturated. One way to address this question is to examine the relationship between local species richness (LSR) and regional species richness (RSR) in standardised samples taken from comparable habitats from different geographical areas. Here, we suggest a method to remove a possible source of bias in the typical method of analysis and then we make some additional suggestions regarding statistical testing.