We recorded 49 species using phytosociological plots and 65 species in the floristic compilation. Richness estimators calculated the local Alfa diversity to be between 68 and 85 species. We show that sampling 80% of the total local richness would require 100plots, which is a reasonable sampling effort, but to sample 99% of the species, an extremely large amount of sampling would be needed (580 plots). This is not practical during fieldwork. We show here how rarefaction and extrapolation can be used as a framework to gauge the amount of field effort needed in aquatic ecosystems.