Aim The mechanisms underlying the maintenance of biodiversity remain to be elucidated. Taxonomic diversity alone remains an unresolved issue, especially in terms of the mechanisms of species co‐existence. We hypothesized that phylogenetic information could help to elucidate the mechanism of community assembly and the services and functions of ecosystems. The aim of this study was to explore the mechanisms driving floral diversity in subtropical forests and evaluate the relative effects of these mechanisms on diversity variation, by combining taxonomic and phylogenetic information. Location We examined 35 1‐ha tree stem‐mapped plots across eight national nature reserves in Guangxi Zhuang Autonomous Region, China. Taxon Trees. Methods We quantified the taxonomic and phylogenetic β‐diversity between each pair of plots using the (abundance‐based) Rao's quadratic entropy and the (incidence‐based) Sørensen dissimilarity indices. Using a null model approach, we compared the observed β‐diversity with the expected diversity at random and calculated the standard effect size of the observed β‐diversity deviation. Furthermore, we used distance‐based redundancy analysis (dbRDA) to partition the variations in taxonomic and phylogenetic observed β‐diversity and β‐deviation into four parts to assess the environmental and spatial effects. Results The taxonomic β‐deviation was related to and higher than the phylogenetic β‐deviation ( r = .74). This indicated that the species turnover between pairwise plots was mainly the turnover of closely related species. Higher taxonomic and phylogenetic β‐deviation were mainly concentrated in the pairwise karst and nonkarst forest plots, indicating that the species in karst forests and nonkarst forests were predominantly from distantly related clades. A large proportions of the variation in taxonomic and phylogenetic β‐deviation were explained by the joint effect of environmental and spatial variables, while the contribution of environmental variables was greater than that of spatial variables, probably owing to the influence of the sampling scale dependence, integrality of sampling size and species pool, and the unique climatic and geomorphic characteristics. Main conclusions Our study highlights the importance of phylogeny in biodiversity research. The incorporation of taxonomic and phylogenetic information provides a perspective to explore potential underlying mechanisms that have shaped species assemblages and phylogenetic patterns in biodiversity hotspots.

Spiders are a functionally important taxon in forest ecosystems, but the determinants of arboreal spider beta diversity are poorly understood at the local scale. We examined spider assemblages in 324 European beech (Fagus sylvatica) trees of varying sizes across three forest stands in Würzburg (Germany) to disentangle the roles of tree architecture, spatial distance, and dispersal capacity on spider turnover across individual trees. A large proportion of tree pairs (66%) showed higher compositional dissimilarity in spider assemblages than expected by chance, suggesting prominent roles of habitat specialization and/or dispersal limitation. Trees with higher dissimilarity in DBH and canopy volume, and to a lesser extent in foliage cover, supported more dissimilar spider assemblages, suggesting that tree architecture comprised a relevant environmental gradient of sorting spider species. Variation partitioning revealed that 28.4% of the variation in beta diversity was jointly explained by tree architecture, spatial distance (measured by principal coordinates of neighbor matrices) and dispersal capacity (quantified by ballooning propensity). Among these, dispersal capacity accounted for a comparable proportion as spatial distance did (6.8% vs. 5.9%). Beta diversity did not significantly differ between high- and low-vagility groups, but beta diversity in species with high vagility was more strongly determined by spatially structured environmental variation. Altogether, both niche specialization, along the environmental gradient defined by tree architecture, and dispersal limitation are responsible for structuring arboreal spider assemblages. High dispersal capacity of spiders appears to reinforce the role of niche-related processes.

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Directly separating minor actinides (MA: Am, Cm, etc.) from high level liquid waste (HLLW) containing lanthanides and other fission products is of great significance for the whole nuclear fuel cycle, especially in the aspects of reducing long-term radioactivity and simplifying the post-processing separation process. Herein, a novel silica-based adsorbent Me2-CA-BTP/SiO2-P was prepared by impregnating Me2-CA-BTP (2,6-bis(5,6,7,8-tetrahydro-5,8,9,9-tetramethyl-5,8-methano-1,2,4-benzotriazin-3-yl)pyridine) into porous silica/polymer support particles (SiO2-P) under reduced pressure. It was found Me2-CA-BTP/SiO2-P exhibited good adsorption selectivity towards 241Am(III) over 152Eu(III) in a wide nitric acid range, acceptable adsorption kinetic, adequate stability against γ irradiation in 1 and 3 M HNO3 solutions, and successfully separated 241Am(III) from simulated 3 M HNO3 HLLW. In sum, considering the good overall performance of Me2-CA-BTP/SiO2-P adsorbent, it has great application potential for directly separating MA from HLLW, and is expected to establish an advanced simplified MA separation process, which is very meaningful for the development of nuclear energy.

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