In the last decade, the phylogenetic relationships within the genus Triplophysa have become controversial, due to a lack of molecular data. The mitochondrial genome plays a vital role in the reconstruction of phylogenetic relationships and in revealing the molecular evolution of bony fishes. Herein, we obtained the complete mitogenome of Triplophysa bombifrons via HiFi reads of the Pacbio Sequel II system and DNBSEQ short-reads. We compared all available mitogenomes of the Triplophysa genus and reconstructed the phylogeny of Nemacheilidae, based on the mitogenomes, using maximum likelihood (ML) methods. The results show that the complete mitogenome sequence of T. bombifrons was circular and 16,568 bp in length, including 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA), 2 ribosomal RNA (rRNA), and a typical control region (D-loop). The most common start codons were ATG, except for cox1, and TAA/TAG were the stop codons for all PCGs. In total, 677 SNPs and 9 INDELs have been found by comparing the sequence divergence between this study and previous reports. Purity selection was found in all PCGs. Phylogeny was inferred by analyzing the 13 PCGs and the concatenated nucleotide sequences of 30 mitogenomes. The phylogenetic analyses based on the nucleotides of the 13 PCGs supported the assumption that the Triplophysa genus can be divided into 4 main clades and demonstrated that T. bombifrons and T. tenuis are closely related species for the first time. This study laid the foundation for further study on the mitogenome and phylogeny of Nemacheilidae fishes.

Environmental DNA (eDNA) metabarcoding is a powerful method for monitoring aquatic biodiversity and evaluating ecosystem health. In this study, we applied eDNA metabarcoding and a multi-species biotic integrity index (Mt-IBI), constructed by selecting and screening core metrics to capture key ecological responses, to assess the Irtysh River Basin in Xinjiang, China, analyzing samples from 52 sites. The community structure showed high sensitivity to environmental stressors, with dissolved oxygen (DO), total nitrogen (TN), and elevation being key factors, while alien fish richness negatively impacted ecosystem health. These findings highlight the importance of maintaining environmental parameters and controlling invasive species, demonstrating the potential of the Mt-IBI for early detection of ecological degradation and guiding freshwater conservation.

Little is known about how changes in the biodiversity and functional traits of macroinvertebrates in rivers respond to the responses of anthropic pressures and their driving factors. Macroinvertebrates were sampled at 17 sites in the Irtysh River Basin and classified macroinvertebrates into 10 traits and 38 categories between May and August 2022. Then, we performed R-mode linked to Q-mode (RLQ) analysis and calculated functional richness, evenness, divergence, and Rao’s quadratic entropy (RaoQ) for each site and community-weighted means for each trait category. Our results indicated that there were pronounced alterations in species variability in the urban region. Functional divergence indicated fierce competition among species and considerable niche overlap in the urban region. Functional evenness indicated that species abundance distribution and interspecific functional distance were not uniform in the urban region. Functional richness indicated that the urban region was the strongest region in terms of niche occupation, resource utilization, and buffering capacity for environmental fluctuations. Rao’s quadratic entropy showed that the trait difference of macroinvertebrates was the largest in all regions, which was caused by the gradient environmental difference. Research has revealed that urbanization significantly influences the evolutionary trajectory of macroinvertebrate fauna, culminating in an upsurge in pollution-tolerant species and a convergence of functional traits. We recommend strengthening the control of urban and industrial pollution and wise planning and management of land and water resources to mitigate the impact of anthropogenic destruction on habitat fragmentation in the Irtysh River Basin.

This study investigated the spatial and temporal variations of macrobenthos community structure in the Yuqu River Basin during the dry and wet seasons due to environmental factors. This study quantified the independent and interactive contributions of hydrophysical, hydrochemical, and climatic factors to the community structure through a variance decomposition analysis (VPA). The study findings indicate that during May (the dry season), factors such as water depth, flow velocity, dissolved oxygen, and air temperature exhibit relatively minor fluctuations, rendering the aquatic environment more stable than in the rainy season. This stability is particularly conducive to the maintenance of the macrobenthic community structure and species diversity, which is especially evident in aquatic insects with nesting habits, such as those belonging to the Trichoptera order (including genera like Glossosoma, Glossosomatidae, and Georodes). In contrast, during August (the rainy season), substantial precipitation alters the thermal conditions of the river, increases flow velocity, raises water levels, and introduces a significant influx of organic matter through sedimentation. This distinctive ecological environment fosters unique adaptive strategies among macrobenthic organisms. Notwithstanding a notable decline in species diversity during this particular phase, there is a concurrent increase in the abundance of individual organisms, which is indicative of the populations’ remarkable capacity to swiftly adapt to environmental heterogeneity. Research has demonstrated that macrobenthic communities within the Yuqu River Basin adopt pronounced adaptive tactics that vary significantly between seasons. During the dry season, these macrobenthic fauna rely heavily on the stability of their physical habitat. In stark contrast, they are compelled to navigate and cope with the more intricate and dynamic changes in hydrological and chemical conditions that characterize the rainy season. The presented results uncover the sensitive responsiveness of the macrobenthic fauna to seasonal hydrological and environmental fluctuations in high-altitude river systems and their adaptive strategies under diverse ecological stressors. Arthropods, in particular, exhibit a marked sensitivity to seasonal hydrological and environmental changes. This study delves into the biodiversity of high-altitude river ecosystems, analyzing the ecological environment and the distribution patterns and seasonal variation characteristics of macrobenthic communities. This study aims to examine how diverse seasons and hydroclimatic conditions modulate the composition of macrobenthic assemblages within the tributaries and principal channels of high-altitude river systems, thereby establishing a foundational reference for future water ecosystem assessments in such regions.

To study the morphological differences between and the evolutionary mechanisms driving the differentiation of geographically distinct populations of Gymnodiptychus dybowskii, 158 fish were collected from the Turks River and the Manas River in Xinjiang from 2020 to 2021 with the approval of the Academic Ethics Committee. The morphological characteristics of the fish were assessed using classical fish ecology methods such as traditional morphometric measurements and the framework approach. The results showed that the morphological characteristics of the populations in the Turks River and Manas River were significantly different; a one-way ANOVA revealed 22 highly significant differences (p < 0.01) and 1 significant difference (p < 0.05) among the 33 morphological traits of the observed populations, and a principal component analysis revealed that there was no overlap between the two populations of G. dybowskii. The main characteristics associated with principle component 1 were the terminus of the dorsal fin to the ventral origin of the caudal fin (D—F), the dorsal origin of the caudal fin to the origin of the anal fin (E—H), and the insertion of the pectoral fin to the terminus of the pectoral fin (J—K); the main factors associated with principal component 2 were the body height (BD), the terminus of the dorsal fin to the insertion of the pelvic fin (D—I), the caudal peduncle height (CPH), and the tip of the snout to the last end of the frontal maxilla (A—B); and the main traits associated with principle component 3 were the terminus of the anal fin to the origin of the anal fin (G—H), the body width (BW), the insertion of the pelvic fin to the terminus of the pelvic (I—L), the insertion of the pectoral fin to the terminus of the pectoral fin (J—K), and the insertion of the pelvic fin to the insertion of the pectoral fin (I—J). An OPLS-DA revealed that the two populations could be wholly separated and that the intergroup growth traits of the Manas River population were different and significantly greater than those of the Turks River population. The discriminant functions of the Turks River and Manas River populations of G. dybowskii were as follows: Y_T = −432.033 + 1787.748X₁ + 826.517X₂ + 249.002X₃ + 1183.050X₄ + 554.934X₅ + 999.296X₆ + 627.428X₇; Y_M = −569.819 + 2041.044X₁ + 344.942X₂ + 333.737X₃ + 940.512X₄ + 348.222X₅ + 1167.770X₆ + 1015.904X₇. According to a coefficient of variation analysis, a total of nine traits, namely, EI/BL, C-D/BL, E-F/BL, F-H/BL, H-I/BL, C-J/BL, D-I/BL, D-H/BL, and D-F/BL, had a CD > 1.28, indicating that the differences in these nine traits had reached the subspecies level. The results showed that G. dybowskii significantly differed between the two geographically distinct populations in the Turks River and the Manas River and have differentiated to the subspecies level. This study provides a basis for a better investigation of the population structure of highland endemic fishes and the mechanisms by which they diverged and lays a foundation for developing and utilizing germplasm resources from endemic fishes in Xinjiang.

This study investigates the mechanisms of zooplankton community assembly and their relationship to environmental factors in high-latitude arid regions. We conducted seasonal sampling at four reservoirs in the upper Tarim River Basin from 2023 to 2024: Shangyou Reservoir (SY), Shengli Reservoir (SL), Duolang Reservoir (DL) and Xinjingzi Reservoir (XJZ). The zooplankton community was categorized into five functional groups based on the predominant species, with small crustacean filter feeders (SCF) in all reservoirs except XJZ, where a seasonal shift between rotifer collectors (RC) in the wet season and SCF in the dry season was observed. Pearson correlation and canonical correspondence analysis (CCA) revealed that interspecific competition, pH, conductivity (COND), and salinity (SALIN) were the main determinants of zooplankton community composition. Significant correlations (p < 0.05) were detected among functional groups RC (rotifers carnivora), RF (rotifers filter feeders), SCF (small copepods and claocera filter feeders), and MCC (middle copepods and claocera carnivora). Environmental factors showed significant spatial heterogeneity, while zooplankton biomass was positively correlated with pH and COND. Cluster similarity analyses indicated complex interactions between 29 zooplankton species, with RF identified as an important positive predictor for larger groups. The network of co-occurrences showed predominantly positive relationships, emphasizing the mutual facilitation between the species. Our results suggest that interspecific interactions have stronger effects on community structuring than environmental factors, with mutual facilitation emerging as an important survival strategy. This study provides important insights into the dynamics of zooplankton communities in dry reservoirs and establishes a framework for understanding ecological patterns and assembly mechanisms under drought conditions.