This study aims to conduct a comprehensive safety assessment of two novel pesticides—tetraniliprole (SZ) and Metarhizium anisopliae (LJ)—with the goal of providing scientific data to underpin the refinement of current risk assessment frameworks for new pesticides and guiding the optimization of field application strategies. Using the predatory insect A. custos as a model organism, we designed negative control (CK) and concentration-gradient experiment to investigate the effects of these pesticides on the physiological indices and growth performance of A. custos . Additionally, we analyzed their impacts on the structural and functional characteristics of the intestinal fungal community in A. custos , as well as the interaction mechanisms between gut fungi and host physiological-biochemical processes. The results showed that: (1) at 72 h post-pesticide application, the body weight growth rate of A. custos was higher in the SZD and SZG groups than in the control (CK), with the order SZD > SZG > CK; similarly, the LJG and LJD groups also exhibited higher growth rates than CK, following LJG > LJD > CK. (2) By 120 h post-application, the survival rate of CK was higher than that of the SZD and SZG groups (CK > SZG > SZD), and also higher than that of the LJG and LJD groups (CK > LJG > LJD). (3) The abundance of M. anisopliae was positively correlated with the activities of catalase (CAT), carboxylesterase (CarE), superoxide dismutase (SOD), glutathione S-transferase (GST), and acetylcholinesterase (AChE) in A. custos ( p < 0.05). Conversely, tetraniliprole was negatively correlated with CAT and CarE activities ( p < 0.05). (4) Deterministic ecological processes were the dominant drivers shaping the assembly of the intestinal fungal community in A. custos under the LJ and SZ treatments. (5) In the LJ treatment group, M. anisopliae absolutely dominated the intestinal fungal community, suppressing the growth of other fungal taxa. In the SZ group, environmentally widespread species such as Candida parapsilosis and Aspergillus penicillioides became characteristic intestinal fungal groups. In conclusion, M. anisopliae showed higher safety for predatory insects compared to tetraniliprole. These findings facilitate the construction of more robust risk assessment frameworks for novel pesticides and provide theoretical insights for promoting sustainable agricultural practices within the ecological civilization development paradigm.

Understanding the mechanisms that maintain biodiversity is crucial for effective conservation in riverine ecosystems. However, the direct and indirect mechanisms by which land use patterns and water quality parameters influence plankton α- and β-diversity remain poorly elucidated. Here, we undertook a comprehensive survey of plankton communities across the Jialing River basin. Our results showed that Bacillariophyta and Chlorophyta were the dominant phytoplankton groups, whereas Protozoa and Copepoda predominated among zooplankton. Redundancy analysis identified dissolved oxygen and total phosphorus as key environmental factors shaping plankton community structure. Additionally, random forest models indicated that anthropogenic stressors exerted consistent effects on both α- and β-diversity of phytoplankton. Importantly, the decomposition of β-diversity revealed that species turnover constituted the major component, underscoring the importance of basin-scale management approaches. Structural equation modeling further demonstrated that land use practices predominantly affected phytoplankton β-diversity indirectly via water quality alterations, with a relatively weak direct effect. In contrast, neither the direct nor indirect effects of land use were significant for zooplankton communities. These findings suggest that phytoplankton may serve as more reliable bioindicators of anthropogenic disturbance than zooplankton in this freshwater system. Moreover, our findings highlight the central role of water quality in regulating phytoplankton diversity responses to environmental change. Consequently, we recommend that conservation strategies in the Jialing River basin focus on water quality monitoring and the mitigation of its ecological effects.

Anthropogenic activities (represented by dams and land use change) and climate change have disrupted the delicate balance between natural and anthropogenic factors affecting riverine material transport, yet their effects across different river basins remain underexplored. This study investigated multi-decade (1980–2023) variations in sediment and particulate carbon (C), nitrogen (N), and phosphorus (P) exports from the Jinsha (JSR) and Jialing River (JLR) basins, two cascading developmental river systems in Southwestern China, and evaluated the cumulative impacts of land use change and dam construction. The results revealed significant decreases in particulate fluxes from both basins, despite stable water discharge. Particulate material fluxes declined by 90.9–99.6% in the JSR (last decade vs. 1980–1989, with an abrupt change occurring during 2002–2003) and by 54.0–79.3% in the JLR (with an abrupt change occurring in 1994). Over time, the influence of precipitation and water discharge on material transport has diminished, whereas land use change and dams have become increasingly dominant. Key drivers include forest expansion, increased impervious surfaces, reservoir construction, and reductions in grassland and farmland; however, there are spatial differences in the relative importance of these drivers. This study provides crucial insights for decision making on regional ecological conservation and cascading development.

Sand mining activities can significantly impact the microecology of rivers. Scientific studies are needed for the effective protection and restoration of river ecosystems impacted by sand mining activities. In this study, we used high-throughput sequencing technology to analyse the structure and function of sediment bacterial communities in three river habitats of the Jialing River Basin, namely, a natural river channel (no sand mining activities), a channel with continuous large-scale sand mining activities, and a channel in which sand mining had been terminated one year prior, as well as to analyse the main constraints leading to changes in sediment bacterial communities. The results revealed that the dominant bacteria in the different sand mining environments of the Jialing River were Proteobacteria, Chloroflexi, and Acidobacteria, and that total organic carbon (TOC), moisture content (MC) and total nitrogen (TN) were the main limiting factors affecting the structure of the bacterial community. In addition, large-scale sand mining activities caused significant changes (p < 0.05) in major secondary functions, such as energy metabolism, cofactor and vitamin metabolism, and translation. In summary, the persistence of large-scale sand mining activities led to heterogeneous changes in sediment bacterial community structure and function, which had an important impact on the stability of the ecosystem in the Jialing River Basin.

Urbanization imposes multiple environmental stressors on urban rivers. Zooplankton are sensitive to environmental disturbances, making them useful tools for assessing ecological health and revealing river degradation processes. We surveyed the urban reaches of the middle and lower Jialing River and its tributary (Xichong River) during autumn 2022 and spring 2023. Water ecological status was assessed using the water quality index and zooplankton-based Index of Biotic Integrity. Community assembly mechanisms and their driving pathways were analyzed by combining the neutral community model (NCM, MST), random forest (RF), and partial least squares path modeling (PLS-PM). Key results: (1) The zooplankton community in the Jialing River Basin exhibited significant spatiotemporal heterogeneity. (2) The overall water ecological status was better in the mainstream than in the tributary, and better in autumn than in spring. (3) Stochastic processes dominated the Jialing River mainstream in autumn (MST = 0.5388), whereas deterministic processes dominated in all other habitats. (4) Seasonal variation was the key driver of community assembly (R² = 0.253, p < 0.001), and COD_Mn was the primary water quality factor (IncMSE = 25.48%). In summary, multiple models combined quantified the dominant pathways of ecological response, providing theoretical support for the health management of urbanized rivers.