Xiongjun Liu

Aim: Growing evidence suggests that, in addition to taxonomic diversity, examining functional and phylogenetic diversity offers distinct yet complementary insights into the spatial and temporal patterns of biodiversity and their driving mechanisms. Here, using a data set comprising 40 years (comparisons of 1984–1995 vs. 2010–2024), we examined spatial and temporal patterns of taxonomic, functional and phylogenetic alpha and beta diversity in fish assemblages in the Pearl River Basin (PRB), China. Location: Pearl River Basin, China. Methods: We used multi‐faceted diversity, principal coordinate analysis and non‐metric multidimensional scaling to analyse the spatial and temporal changes in fish biodiversity; Mantel tests and variation partitioning analysis were used to analyse the role of environmental and spatial variables on the multi‐faceted diversity indices. Results: Fish assemblages exhibited significant spatial and temporal differences. Taxonomic alpha diversity of the PRB declined, but functional and phylogenetic alpha diversity increased over the analysed time period. Taxonomic and phylogenetic beta diversity showed an increased trend, but functional beta diversity declined over time. The nestedness component towards taxonomic and phylogenetic beta diversity was higher and lower than the spatial turnover component in the analysed time periods, respectively. In addition, the nestedness component towards functional beta diversity was higher than the spatial turnover component in the historical time period, and was lower in the current time period. Environmental variables were more important than spatial variables in explaining the taxonomic diversity, and spatial variables were more important in explaining functional and phylogenetic diversity in the two analysed time periods. Main Conclusions: These results highlight the importance of evaluating taxonomic, functional and phylogenetic alpha and beta diversity to better understand biodiversity patterns and their driving mechanisms. Overall, the information provided by the three types of diversity is more comprehensive and offers valuable insights for biodiversity conservation, as well as monitoring and management of the PRB or other subtropical rivers experiencing similar anthropogenic disturbances.

Biodiversity loss has increased interest in understanding biodiversity patterns and their driving mechanisms in global. A growing of empirical evidence suggests that, in addition to purely species diversity, studies of phylogenetic diversity can provide distinct but complementary information about biodiversity patterns and their driving mechanisms. However, there was still a lack of research on integrating species and phylogenetic diversity to analyse the spatial patterns and driving mechanisms of fish diversity. Here, we evaluated the response of species diversity and phylogenetic diversity of fish assemblages to environmental factors in Jiangxi Province. The results showed that 243 fish species were recorded in Jiangxi province, including 14 invasive species. There were 126 species native to China and 33 species endemic to the Yangtze River Basin. The Red List of China and IUCN assessments showed that 31 (12.8%) and 16 (6.6%) species were Threatened or Near Threatened (1 Extinct; 6 and 1 Critically Endangered; 3 and 3 Endangered, 8 and 5 Vulnerable, 14 and 6 Near Threatened), respectively. The number of species in carnivorous (111), demersal (143) and resident (153) fish were higher than other functional taxa. Fish species diversity was not significantly spatial differences (p = 0.521), and phylogenetic diversity exhibited significantly spatial differences (p = 0.001). The species spatial turnover (0.53) was higher than the nestedness (0.17), a larger number of protected areas would be necessary to conserve the regional biodiversity. Environmental and geographic factors generally had no significant effect on the species and phylogenetic diversity, and only nitrate nitrogen was significantly correlated with the species diversity and phylogenetic diversity. The results highlight the importance of evaluating both species and phylogenetic diversity when identifying biodiversity patterns and their driving mechanisms and provide useful implications and guidance for biodiversity conservation in the Yangtze River and in other regions facing human disturbances.

The Yangtze River is one of the largest riverine ecosystems in the world and is a biodiversity hotspot. In recent years, this river ecosystem has undergone rapid habitat deterioration due to anthropogenic disturbances, leading to a decrease in freshwater biodiversity. Owing to these anthropogenic impacts, the Chinese government imposed a “Ten‐year fishing ban” (TYFB) in the Yangtze River and its tributaries. Ecological changes associated with this decision have not been documented to evaluate the level of success. This study evaluates the success of the TYFB by analyzing the changes in phytoplankton communities and comparing them to periods before the TYFB was imposed. A total of 325 phytoplankton species belonging to 7 phyla and 103 genera dominated by Chlorophyceae and Bacillariophyceae were identified. Species diversity according to the Shannon–Wiener ranged between 1.19 and 3.00. The results indicated that phytoplankton diversity increased, while both density and biomass decreased after the TYFB. The health of the aquatic ecosystem appeared to have improved after the TYFB, as indicated by the phytoplankton‐based index of biotic integrity. Significant seasonal and spatial differences were found among the number of species, density, and biomass of phytoplankton, where these differences were correlated with pH, water depth, chlorophyll‐a, permanganate index, transparency, copper, ammonia nitrogen, and total phosphorus based on redundancy analysis. Results from this study indicate that the TYFB played an important role in the restoration of freshwater ecosystem in the Yangtze River and its tributaries.

The loss of lateral hydrological connectivity (LLHC) in freshwater ecosystems is increasingly threatening biodiversity; however, studies reporting this situation are limited, especially those assessing multi‐measure biodiversity features at large spatial scales. Here, and using one the most threatened taxonomic groups in freshwater ecosystems, we examined the possible influence of LLHC on the species diversity, density, and biomass of mussel assemblages and the genetic diversity and structure of Nodularia douglasiae (a common and widespread native species) in the Yangtze River floodplain. Results showed that the species diversity of freshwater mussels (α and β diversity) significantly differed between the connected and the disconnected areas, with higher α diversity and lower β diversity in the connected areas. At the same time, relative abundance, density, biomass, and genetic diversity of freshwater mussels were higher in the connected areas. High genetic differentiation and low gene flow were found among the 18 analysed N. douglasiae populations, indicating that LLHC is affecting genetic structure of this particular freshwater mussel species. Overall, results indicated that river–lake connectivity is affecting freshwater mussel biodiversity. In addition, this study highlights that multi‐measure biodiversity features provide distinct information about biodiversity dynamics, and are essential to evaluate the effects of floodplain disconnection. We advocate that an integrative approach to floodplain management embracing species and genetic diversity is needed for effective biodiversity conservation in large river ecosystems.

Accurate identification and precise classification of freshwater mussel species that are among the most threatened freshwater taxa in the world, play a crucial role in informing conservation and management efforts for these organisms. However, due to the variability in shell morphology, relying solely on shell characteristics for species taxonomy poses significant challenges, thereby impeding effective conservation planning and management. The freshwater mussel genus Ptychorhynchus Simpson, 1900 is one such group in need of study. We integrate molecular phylogeny, shell morphology and soft-body anatomy to examine the classification of Ptychorhynchus denserugata (Haas, 1910) and Ptychorhynchus resupinatus (von Martens, 1902). The COI barcoding data support the clustering of P. denserugata and Nodularia douglasiae within a single clade, and P. denserugata shares the diagnostic feature of the genus Nodularia, i.e. knobs or bumps on the inner mantle surface in the excurrent aperture. Therefore, by integrating molecular data and anatomical characteristics, we confirm that the nominal species P. denserugata syn. nov. is a new synonym for N. douglasiae. The multi-locus (COI + ND1 + 16S rRNA + 18S rRNA + 28S rRNA) phylogeny and mitochondrial phylogenomics support the transfer of P. resupinatus from Ptychorhynchus to the newly elevated genus Cosmopseudodon stat. rev., as Cosmopseudodon resupinatus stat. rev. that is still considered the designated type species. We also describe a new species based on integrative taxonomy, i.e. Cosmopseudodon wenshanensis sp. nov. The comprehensive understanding of the taxonomy and diversity of the revised Cosmopseudodon species, and shell heteromorphism of N. douglasiae (=P. denserugata syn. nov.), will serve as a crucial foundation for further scientific assessment and conservation strategies pertaining to these taxa. ZooBank: urn:lsid:zoobank.org:pub:E48968B1-DF0F-42AD-8F31-B8C95F23CE57

Freshwater bivalves (Bivalvia, Unionida) are one of the most threatened groups of animals in the world. Defining species boundaries and understanding the phylogeny and genetic diversity of these species is key to guiding their conservation and management. However, the presence of significant phenotypic plasticity and convergence within this group complicates species delimitation. This includes the freshwater mussel genus Nodularia, endemic to East Asia, for which a comprehensive understanding of species diversity and phylogenetic relationships remains elusive due to inadequate sampling in previous studies, particularly in China, a widely recognized biodiversity hotspot for freshwater mussels. Here, we conduct comprehensive taxonomic and phylogenetic analyses of Nodularia species based on extensive sampling across 23 provinces in China and multiple data sources, including shell morphology, soft body anatomy, six‐gene (COI + ND1 + 16S + 18S + 28S + histone H3) and mitogenome datasets. The integrative systematics approach used here reveals 10 distinct species in this genus, four of which are new to science, i.e. Nodularia hanensis sp. nov., Nodularia huana sp. nov., Nodularia fusiformans sp. nov., Nodularia dualobtusus sp. nov. and two of which are new records for China, i.e. Nodularia dorri (Wattebled [Journal de Conchyliologie, 34, 1886, 54]) and Nodularia micheloti (Morlet [Journal de Conchyliologie, 34, 1886, 75]). We also propose that the nominal species Nodularia jourdyi (Morlet [Journal de Conchyliologie, 34, 1886, 75]) syn. nov. is a new synonym for Nodularia douglasiae (Griffith & Pidgeon, 1833) based on molecular data. BI, ML, and BEAST analyses based on the six‐gene dataset and mitochondrial phylogenomics consistently support the following phylogenetic relationships: (N. dorri + (N. hanensis sp. nov. + N. micheloti)) + (N. breviconcha + (N. huana sp. nov. + (N. fusiformans sp. nov. + ((N. nuxpersicae + N. nipponensis) + (N. dualobtusus sp. nov. + N. douglasiae))))). The molecular clock with fossil calibration indicates that Nodularia originated in the Late Cretaceous period (ca. 73.78 Mya). It then diverged into two independent clades during the Middle Paleogene (ca. 45.01 Mya), followed by a rapid burst of extant speciation during the Neogene (mean age 28.28 to 4.79 Mya). Nodularia breviconcha is the earliest differentiated taxon among the 10 Nodularia taxa, appearing during the Paleogene‐Neogene transition (28.28 Mya; 95% HPD = 14.35–48.44 Mya). Taken together, we provide a robust systematic framework for Nodularia species, addressing phylogenetic relationships, taxonomy, and evolutionary history of this group.

Accurate phylogenetic reconstructions are crucial for comprehending the evolutionary histories, reproductive traits, and ecological habits of organisms. The subfamily Gonideinae of freshwater mussels is currently thought to include eight tribes. However, due to inadequate taxon sampling and molecular data, the assignment of the freshwater mussel genus Inversidens at the tribe level has been unstable. Additionally, the lack of phylogenetic data has hindered efforts to understand the basic biology and implementation of conservation efforts of Inversidens rentianensis, an endemic species to China. Here, we first present the complete mitochondrial genome of Inversidens rentianensis and offer a detailed description of its anatomical morphology. Based on DNA sequence data from five genes (COI, ND1, 16S rRNA, 18S rRNA, and 28S rRNA) and complete mitochondrial genomes, we investigated the phylogenetic position of Inversidens using various analytical methods. Both the concatenated five-gene and mitogenome datasets strongly supported that Inversidens classified to the tribe Gonideini in Gonideinae and formed a basal clade within the tribe Gonideini. Molecular dating analysis suggested that Inversidens originated during the mid-Cretaceous era (102.73 Mya, 95% highest posterior density Mya) and underwent diversification in the Late Paleogene era (37.92 Mya, 95% Mya). Moreover, based on the Quantitative Assessment of Species for Conservation (QASCP), Inversidens rentianensis is ranked as second priority, providing valuable insights for its management and conservation efforts. Taken together, this study provides a comprehensive understanding of the systematic position and evolutionary history of Inversidens within the currently accepted subfamily Gonideinae classification framework. These findings establish a solid foundation for future investigations on the ecology, reproductive behavior patterns, and conservation biology of this taxonomic group.

Peroxidation during organism growth and development might have catastrophic implications. It is critical to further investigate the antioxidant potential of plant anthocyanins. In this study, anthocyanins from Eleutherococcus brachypus fruits (EBF) were extracted by an ultrasonic-assisted method. The anthocyanins were then tested for stability under various storage conditions. Based on single-factor combination with response surface optimization, the best ethanol concentration for anthocyanin extraction was 75, the ideal ultrasonic irradiation power was 160W, the liquid-to-solid ratio was 10.18mL/g, and the maximum anthocyanin yield was 1.86mg/g. Anthocyanins are readily degraded by bright light and remain stable under acidic storage conditions (pH 3.0) and at temperatures below 60°C. The inhibition rates of anthocyanins against ABTS and DPPH radicals were 54.59 and 48.70, respectively, using vitamin C (Vc) as a positive control. The data cited above make it clear that anthocyanins may act as natural antioxidants. In addition, this research provides a sound theoretical foundation for the creation of natural green antioxidants.

Invasive species are one of the most serious threats to biodiversity. Pomacea canaliculata is considered one of the world’s 100 worst invasive species. Major determinants of invasive species distribution are their environmental tolerances, and an understanding of correlations between local environmental variables (e.g., pH, concentration of dissolved oxygen) and genetic diversity is necessary to better prevent and manage the spread of invasive species. However, while such studies have demonstrated associations between the distribution and density of P. canaliculata and water quality correlates, the principal mechanisms relating genetic and these environmental correlates have not been fully articulated. Here, the correlation between physicochemical parameters and genetics of P. canaliculata were analyzed. The results showed that P. canaliculata among the six collection locations had robust genetic diversity, significant genetic differentiation, limited gene flow, and stable population dynamics. RDA analysis showed that genetic variation in P. canaliculata was significantly correlated with concentration of dissolved oxygen and pH. These results will provide a basis for effectively preventing and managing the spread of invasive species and identifying which habitats may be more at risk of invasion.