Spatial and local environmental factors outweigh geo‐climatic gradients in structuring taxonomically and trait‐based β‐diversity of benthic algae

Abstract

AbstractAimUnderstanding the variation in biodiversity and its underlying drivers and mechanisms is a core task in biogeography and ecology. We examined (a) the relative contributions of species replacement (i.e., turnover) and richness difference (i.e., nestedness) to taxonomically and trait‐based β‐diversity of stream benthic algae; (b) whether these two facets of β‐diversity are correlated with each other; and (c) the relative contributions of local environmental, geo‐climatic and spatial factors to the two facets of β‐diversity and their components.LocationHun‐Tai River Basin, northeastern China.TaxonStream benthic algae.MethodsA total of 157 sites were sampled. Mantel tests were used to examine the complementarities between the two facets of β‐diversity and their components. Distance‐based redundancy analysis and variation partitioning were utilized to investigate the relative contributions of local environmental, geo‐climatic and spatial factors to each facet of β‐diversity and their components.ResultsWeak correlations between taxonomically and trait‐based β‐diversity and their components were detected, which indicated complementarity of ecological information. Taxonomically based total β‐diversity was largely driven by turnover, whereas trait‐based total β‐diversity was more driven by nestedness. Variation partitioning results indicated that local environmental and spatial factors contributed more than geo‐climatic variables to the total explained variation in taxonomically and trait‐based β‐diversity.Main conclusionsDifferent facets of β‐diversity and their decomposition are important for understanding diversity patterns of benthic algae relative to abiotic factors. A high level of trait‐based convergence among benthic algae communities, despite high taxonomic divergence, demonstrated turnover of species with similar biological traits across our study region. Our study provides a trait‐based insight into stream benthic algae communities, which was less documented by previous freshwater studies that focused on regions undergoing recovery following human disturbances.