A protocol for the analysis of aquatic biodiversity by multiple β diversities

Abstract

Species assemblage can be fairly unstable in aquatic ecosystems because of strong environmental constraints. Measuring β diversity is one of the most useful tools for assessing community dynamics and differentiations among communities. Whereas many β diversity measurements have been proposed for these issues, we present here a unifying framework based on the properties of Hill number, q, to unravel the complex changes occurring in dynamic communities. Using ideal numerical examples of an aquatic community, the sensitivity of β diversity with q = 0 ∼ 2 was examined. Whereas β diversity for q = 0 has a higher sensitivity to rare species drift (rapid exchanges or migration of many rare species) than do others, β diversity for q = 2 adequately responds to the variation or changes of dominant species. A scatterplot based on these two β diversity measures is proposed for the detailed examination of aquatic community dynamics. We show that the scatterplot is able to describe the monthly dynamics of dominant and rare species in the phytoplankton assemblage of a freshwater lake in Japan.