ConclusionsWe present here one of the first phytosociological surveys ofaquatic communities in the semiarid region of Brazil. We use thisdata as a model to apply a critical evaluation of the sampling frame-work that will help aquatic botanists to analyze their samplingefforts. After a review of the species richness recorded in floris-tic studies performed in the semiarid region of Brazil, we foundthat most studies seem to have strongly under sampled the localplant communities, which, we believe, offers a very limited view ofthe plant diversity in their study sites. If rarefaction, richness esti-mators and extrapolation curves had been applied in these papers,they would have had a tool to allow them to judge the amount ofsampling needed to collect a satisfactory dataset. Our work appliesa framework that will help researchers determine the adequatesampling effort needed to collect a sufficient amount data, not onlyin the semiarid region of Brazil, but, more importantly, it can beused by aquatic botanists in any geographical region. Furthermore,this framework allows researchers to understand and clearly assessthe limitations of their species sampling.