Testing the higher-taxon approach: a case study of aquatic marcophytes in China’s northwest arid zone and its implications for conservation

Abstract

Assessments of biodiversity are time-consuming and require a high level of expert knowledge. A reduced set of taxonomic ranks other than species has been proved to be useful for rapid and cost-effective assessment of biodiversity. However, few studies have examined how well this method performs for aquatic plant group that of enormous ecological importance. We studied the aquatic plant flora in the arid zone of China and examined whether the distribution of species α- and β-diversity could be predicted well from genus-, and family-levels. Analyses of 3 years field data showed that significant and positive relations exist between α-diversity of species and α-diversity of genera and family in both entire arid zone and five sub-zones. In contrast, β-diversity at species level is difficult to predict from β-diversity indexes at higher taxonomic level. The results indicate that higher-taxon α-diversity, especially at the generic level in our research, can be useful surrogates of species α-diversity for aquatic plants conservation.