Search Results (1,981)

As an effective biological control agent, Propylea japonica (Coleoptera: Coccinellidae) preys on aphids, whiteflies, planthoppers, and small caterpillars, playing a crucial role in pest management within agro-ecological systems. However, the lack of population genomic data has hindered efforts to optimize its use in biological control. We anayzed resequencing data from 166 genomes across 29 populations spanning P. japonica’s distribution in China. This study reconstructed the species’ evolutionary history, assessed population genetic diversity and demographic structure and identified the key environmental factors driving adaptive evolution. Meanwhile, we predicted its suitable habitats across different periods using ecological niche modelling methods. The results indicated that North China (G1, Yellow River Basin) was the likely geographic origin of P. japonica. Northern and southern populations show significant genetic differentiation, with adaptive evolution in the south being the major driver. We identified genomic signatures of selection in adaptive genes associated with increased pesticide resistance and thermal tolerance. Over the past 20,000 years, effective population size of P. japonica experienced an early bottleneck during the Last Glacial Maximum period, and a subsequent rapid expansion. These insights are critical for improving the conservation and application of natural enemies, ultimately enhancing biological control in agricultural systems. Full article

At the current stage, water resource shortages and significant regional disparities in resource distribution severely restrict China’s food security. Existing research primarily focuses on resource use efficiency, while lacking a systematic framework to distinguish between equality and equity in the coupled distribution of irrigation water, grain production, and nitrogen pollution across major river basins. The core objective of this study is to utilize the Concentration Index (CI) to construct a unified equity assessment framework, quantify the evolution of equality and equity in irrigation water use, grain production, and nitrogen loss to surface water in different river basins in China from 1992 to 2017, and determine the key influencing factors. For positive production resources, a distribution that benefits low-income groups is equity, while for pollution burdens, this distribution pattern is inequity. The results show that water shortages in Northern China have intensified, and higher income groups have obtained excessive benefits. The distribution of grain production has shifted from favoring higher income groups to favoring low-income groups, with the Concentration Index changing from 0.214 to −0.052, indicating an enhancement in equity. Irrigation water use has shown a certain degree of improvement, with the CI dropping from 0.023 to 0.017. However, nitrogen loss to surface water has exacerbated environmental inequality, with the CI dropping from 0.10 to 0.03, indicating that pollution burdens have shifted to low-income groups. Changes in equity across the country are driven by a small number of high-intensity grain production areas, and the key influencing factors include food security policies, urbanization, population size, and nitrogen fertilizer application. An asymmetric coupling relationship exists between water resource shortages and equity, and the regional economic foundation determines the formation of synergy or trade-offs. The findings underscore the necessity of transitioning from efficiency-focused to equity-focused agricultural governance in China. Targeted policies should include cross-basin ecological compensation mechanisms, differentiated technology promotion strategies, and integrated water–food-pollution management systems to balance food security, environmental protection, and social justice. Full article

This paper focuses on the Pinghu Formation in the K region of the Xihu Depression, conducting a systematic study on the channel types, migration patterns, and the coupling mechanisms of tectonics, paleogeomorphology, and tidal dynamics in the tidal-controlled and river-controlled composite delta system of the region. By integrating core, well logging, and 3D seismic data, and addressing the challenges of channel identification under the influence of coal seams, methods such as PCA, K-means clustering, and fuzzy c-means clustering were employed for multi-attribute fusion analysis. An indicator system for channel identification and type classification was established, revealing the sedimentary characteristics of tidal-modified delta channels and their planar distribution and migration evolution process. The results of the study indicate that: (1) The early stage of the Pinghu Formation developed a tidal-controlled delta, with channels in network, linear, and dendritic shapes, where individual channels were small and fragmented; in the later stage, it transformed into a river-controlled delta, with sandbodies more concentrated; (2) In areas with weak tectonic constraints, the control of geomorphic boundaries became more prominent, and the barrier islands’ shielding effect on tides led to river-controlled migration of the channels, with limited tidal channels and tidal-modified sandbodies developed only in local areas; (3) The planar distribution and evolution of channels in the study area showed significant differences at different times due to the influences of geomorphology and tectonics. The findings of this paper provide new insights into the sedimentary evolution of tidal-modified delta channels. Full article

Microplastic (MP) pollution in freshwater is an important global issue affecting an increasing number of areas. MP is ingested by aquatic organisms and transferred through food chains, causing impacts on both aquatic life and human health. While studies on MP uptake in the gastrointestinal tract (GIT) of fish are numerous globally, in Romania, there are extremely few. As a result, we conducted research on this phenomenon in fish species from the Crișul Repede River (CR) in two river sectors with different levels of anthropogenic impact. We found out that 100% of the collected fish had MPs in their GIT, with most of the particles being small-sized fragments (0.025–0.1 mm). Upstream, benthopelagic species ingested more MPs than downstream, whereas for benthic species, the amount of MPs in the GIT was greater downstream. Larger individuals contained more MPs than smaller ones. The presence of MPs in fish bodies can pose a problem if these particles enter internal organs and trigger adverse physiological effects. Full article

The Hulukou-Xiangbiling section of the Jinsha River is located in a typical high-mountain gorge area characterized by a complex geological environment, rendering it highly susceptible to landslide disasters. To reveal the deformation mechanisms of typical landslides in this region under hydrological effects, this study employed the Small Baseline Subset InSAR (SBAS-InSAR) technique to process multi-track Sentinel-1 SAR images acquired between 2021 and 2024. Long-term deformation time series were extracted for the Xiaxiaomidi and Chenjiatian landslides. On this basis, a systematic multi-scale coupling analysis of the deformation characteristics was conducted using trend-cycle decomposition, Continuous Wavelet Transform (CWT), Cross Wavelet Transform (XWT), and Wavelet Coherence (WTC). The results indicate that although the two landslides are located in the same river section, their deformation mechanisms and hydrological response patterns differ significantly. The deformation of the Xiaomidi landslide is mainly concentrated in the lower part of the slope, exhibiting a characteristic of continuous acceleration. The analysis demonstrates that the evolution of this landslide is primarily controlled by hydrodynamic processes such as toe unloading, water body erosion, and water level fluctuations. In contrast, the Chenjiatian landslide displays a distinct dominant cycle of 365 days, manifesting as a composite mode of long-term creep superimposed with seasonal acceleration. Its deformation shows a high correlation with rainfall (correlation coefficient > 0.9), with a lag effect of approximately 1 to 2 months. This reflects the dominant role of rainfall infiltration and pore pressure transfer in the landslide dynamics. Full article

Agricultural rivers are often silent receivers of microplastics (MPs) from diffuse, non-point sources; however, their pollution dynamics during rainfall events remain poorly understood. In this study, MP transport was investigated at three sampling points in an agricultural river catchment, where mulching films are used, and sewage sludge is not applied. Sampling was conducted in the Umeda River and its tributaries during six sampling events. MP flux exhibited a strong positive correlation with river discharge (L–Q relationship; n = 1.49–1.61, R² = 0.67–0.87). The L–Q model indicates that a tenfold increase in discharge results in approximately a 600-fold increase in MP flux and a 1000-fold increase in total suspended solid flux. MP abundance during rainfall was up to four times higher than that during baseflow, ranging from 73 ± 64 to 200 ± 111 particles/m³, while peak flux reached 6736 particles/s, with an MP mass of 811 mg/s. Regarding particle characteristics, rainfall enhanced the heterogeneity of MPs, although fragments and polyethylene/polypropylene polymers remained consistently dominant across all hydrological stages. First-flush behavior was observed at HU, with more than half of the total MP mass exported within the initial 50% of the event flow volume. These findings help to inform mitigation strategies that should prioritize a reduction in upstream plastic inputs in order to effectively manage MP transport in agricultural rivers. Full article

The advancement of large-scale marine infrastructure demands increasingly accurate prediction of settlement in deep-water foundations. The caisson is an important type of deep-water foundation whose additional settlement induced by superstructure construction directly impacts the overall safety of the project. This study focuses on the main tower foundation of the Changtai Yangtze River Bridge, recognized as the world’s largest deep-water caisson foundation. A three-dimensional finite element model was developed using the hardening soil model with small-strain stiffness (HSS) constitutive model to simulate the settlement response of the caisson foundation throughout the entire superstructure construction process. The model’s reliability was verified through systematic comparison with field monitoring data. Furthermore, an inversion analysis was conducted on the initial shear modulus ($G_0^{\mathrm{ref}}$), the most sensitive parameter of the HSS model, based on the measured data. The results reveal that its optimal value exhibits significant load dependency, varying according to the construction stage. Accordingly, practical strategies for parameter determination are proposed: a fixed-value method ($G_0^{\mathrm{ref}}$ = 2$E_{\mathrm{ur}}^{\mathrm{ref}}$) suitable for conventional design and a more precise stage-specific value method. Both approaches markedly enhance the settlement prediction accuracy, particularly under high-load conditions. The findings offer valuable insights for the refined design and safety assessment of similar deep-water mega-foundation projects. Full article

The sustainable use of freshwater resources includes balancing between human demand for water and the long-term health of river systems. Although dams and reservoirs are essential for water supply, flood control and energy generation, they can induce significant hydrological alterations, affecting water quality, sediment transport, downstream water availability, and aquatic and riparian ecosystems. In this study, we employed multifractal analysis to investigate hydrological changes in the São Francisco River basin, Brazil, resulting from the construction of a cascade of dams and reservoirs. We applied multifractal detrended fluctuation analysis (MFDFA) to daily streamflow time-series spanning the period from 1929 to 2016, at locations both upstream and downstream of cascade dams, and for periods before and after dam construction. We calculated multifractal spectra f(α) and analyzed key complexity parameters: the position of the spectrum maximum α_0, representing the overall Hurst exponent H; the spectrum width W indicating the degree of multifractality; and the asymmetry parameter r, which reflects the dominance of small (r > 1) and large (r < 1) fluctuations. We found that after the construction of Sobradinho dam, located in the Sub-Middle São Francisco region, streamflow dynamics shifted towards a regime characterized by uncorrelated increments (H~0.5) and stronger multifractality (larger W), with the dominance of small fluctuations (r > 1). In contrast, the cumulative effect of all cascade dams downstream, in the Lower São Francisco region, led to streamflow regime with similarly uncorrelated increments (H~0.5), but with weaker multifractality (smaller W) and a dominance of large fluctuations (r < 1). The novelty of this work is the use of a sliding-window MFDFA approach to explore the temporal evolution of streamflow multifractality. This method uncovered otherwise hidden aspects of hydrological alterations, such as increasing tendency in spectrum width, indicating stronger multifractality and higher complexity of streamflow dynamics after the dam construction. These results demonstrate that multifractal analysis is a powerful tool for assessing the complexity of hydrological changes induced by human activities. Full article

This paper presents a comprehensive real-time forecasting and mapping cycle of a regional flood event, encompassing quantitative precipitation forecasting, runoff production and routing, and inundation mapping. The objective of this study is to highlight the significant uncertainties inherent in each step of the fully automated cycle, despite the utilization of state-of-the-art models and remote sensing technologies. The case study focuses on a significant flood event that occurred in the Turkey River and Upper Iowa River, in rural Iowa, United States, resulting in localized damage and disruption to several small communities. The novelty of this study is that it demonstrates the limited utility of satellite-based remote sensing in the absence of other forecasting and mapping system elements, emphasizing the need for the timely integration of information from diverse sources to accurately forecast and map floods. To achieve this, we assembled and analyzed precipitation data from weather radars, streamflow estimates derived from river stages and rating curves, and cross-sectional data from river channels to characterize the movement of the flood wave. These data were integrated into hydrologic and hydraulic models to generate flood inundation estimates for the more severely affected areas. Remote sensing imagery was obtained and used as reference to assess the accuracy of the modeled inundated areas. Our findings illustrate that, despite the increasing availability of satellite data sources, there are still significant limitations to tracking inundation using satellite remote sensing, particularly for medium-sized basins. Flood modeling processes are not merely complementary to satellite-based flood estimation, but essential for comprehensive flood risk assessment. Full article

Robust visual perception of Aids to Navigation (AtoN) is essential for Maritime Autonomous Surface Ships (MASS) operating in restricted navigational waters, where estuarine clutter, fog, glare, and dense traffic can severely degrade detection reliability. Existing maritime vision datasets largely emphasize open-sea targets or coarse AtoN categories, leaving a granularity gap for IALA-compliant fine-grained understanding in river–sea transition and port-approach channels. The River–Sea AtoN Navigation Dataset (RSAND) is introduced, a large-scale benchmark collected along the Yangtze River Deepwater Channel from inland corridors to open estuarine waters. RSAND contains 39,926 images with expert-verified bounding-box annotations and a hierarchical taxonomy that jointly captures AtoN location, shape, and functional semantics across 29 categories. To support both realistic long-tailed evaluation and standardized model comparison, two protocols are provided: RSAND-Full (29 categories) and RSAND-Balanced (10 critical categories). All quantitative benchmarking results in this paper are reported on RSAND-Balanced, while RSAND-Full is released for future large-scale long-tailed robustness studies. Benchmarking experiments on 14 state-of-the-art detectors demonstrate that YOLOv12x achieves superior performance with an mAP50-95 of 80.7%, significantly outperforming previous baselines. However, the analysis reveals persistent challenges in detecting small, distant targets and distinguishing visually similar functional markers. RSAND and the accompanying evaluation toolkit are released to facilitate reproducible research toward safer and smarter marine and coastal navigation. Full article

Southwest China’s karst region has developed a dam- and reservoir-dense pattern in which cascaded hydropower on mainstem rivers coexists with small hydropower on tributaries, forming a foundation for the region’s low-carbon energy supply. Under China’s “dual-carbon” targets and a strengthening ecological civilization agenda, it is urgent to clarify the mechanisms driving habitat quality (HQ) change under compound disturbances from cascaded hydropower, urbanization, and related pressures—especially the nonlinear pathway through which engineering disturbance propagates to ecological responses via land-use restructuring. To address this need, we develop a Cascade disturbance–Land restructuring–Habitat response chain framework and integrate an InVEST–IntPLUS–OPGD modeling approach to capture HQ dynamics in the Wujiang River Basin (1980–2020), attribute the interactive effects of coupled natural–social drivers, and project ecological responses under alternative 2035 scenarios. Results show that: (1) The basin maintained a stable ecological matrix, with forest land and cropland consistently >82.5% and forest cover near 50%, while construction land increased by 972.15 km² and water bodies by 354.23 km² (2) Mean HQ stayed high and declined by only 1.42%, with high and medium–high HQ dominating (>65%). HQ degradation is concentrated in urban expansion areas and reservoir shorelines, whereas most mountainous/forested regions remain stable; and (3) HQ spatial differentiation is mainly shaped by the synergy between forest structure and NDVI, while nonlinear urbanization edge effects impose stronger stress than hydropower development itself. Scenario simulations further indicate that a water protection pathway can enhance HQ by building integrated “water–forest” corridors that promote blue–green synergy. Overall, this study supports improved trade-off design between energy supply and ecological protection in vulnerable karst regions. Full article

The small towns influenced by the long-term impact of the industrial and mining industries have formed distinctive spatial morphology. A systematic exploration of their spatial form characteristics can make up for the deficiencies of the existing research on spatial form, enrich the theory of urban spatial form, and provide theoretical support for the planning practice of such special towns. Therefore, this paper constructs a theoretical framework of structure–region–boundary and uses methods such as space syntax, shape index, and compactness to comprehensively analyze the spatial morphology gene types of 28 small industrial and mining towns in terms of structure, region, and boundary, and draw the corresponding gene maps. The research results show that in terms of structural genes, the transportation structure of small towns can be classified into grid, branch-shaped, and hybrid types; the relationship between mountains and towns can be categorized as mountain-encircled, mountain-fringed, mountain-adjacent, and no-mountain types; and the relationship between water and towns can be divided into simple intersection, intersection along the short side, intersection along the long side, compound intersection, and no-river types. The common types are grid, mountain-encircled, and no rivers. In terms of regional genes, the texture of small towns can be classified as self-organized, planned, and hybrid types; the public space of streets can be divided into high, medium, and low according to accessibility; the form of industrial and mining processing areas can be classified as terminal, marginal, independent, and central types. Among these, the hybrid, low-accessibility, and terminal types are the most common. In terms of boundary genes, the boundary morphology of most industrial and mining small towns is finger-shaped and uniform. Full article

Freshwater ecosystems in arid and semi-arid zones of the East European Plain are characterized by severe habitat degradation, which negatively impacts their biodiversity. This study attempts to comprehensively examine the species richness of molluscs and determine the influence of abiotic factors on their spatial distribution using the example of one of the river basins in southern Eastern Europe—the Yeruslan River basin (a tributary of the Volga River). Fifteen watercourses in the Yeruslan basin were surveyed, with 72 samples collected from the littoral and deepwater zones. A total of 28 mollusc species were identified in the samples, predominantly those with broad ranges (Holarctic, Palearctic, and Euro-Siberian). Estimating true species richness using nonparametric methods revealed that the collected samples contained at least 90% of the expected number of species. In the small tributaries of the Yeruslan River, the dominant species were the lymnaeids Lymnaea stagnalis (Linnaeus, 1758) and Radix auricularia (Linnaeus, 1758). The Yeruslan River is dominated by the non-native species Dreissena polymorpha (Pallas, 1771). The low values of the Shannon diversity index recorded in the rivers of the Yeruslan basin are typical of desert and semi-desert riverine ecosystems with low stability and productivity, caused by the constant reduction in habitats due to periodic and/or permanent drying. It was established that the most significant abiotic factors determining the distribution of molluscs are the bottom substrate and the concentrations of nitrites and phosphates. Moreover, non-critical concentrations of the latter in the water likely had a beneficial effect on the productivity of streams in an arid climate. Full article

Addressing the issues of the complex mechanical responses and significant spatial effects of asymmetric large-span cable-stayed steel box girder bridges with shared public-rail traffic under operational loads (live load, static wind, and structural temperature differences), this paper uses the Lijiatuo Yangtze River Double-Line Bridge on Chongqing Metro Line 18 as the engineering background to construct multi-scale finite element models for the entire bridge and the closure segment, and validates them against GNSS displacement and strain monitoring data from the actual bridge. The study shows that the spatiotemporal asymmetry of operational live loads induces significant lateral bias effects in the main bridge, resulting in reverse displacements in the mid-span section, and with stress distributions characterized by “oscillation in the side spans and concentration in the mid-span.” The study also shows that, under static wind loads, the bridge’s lateral displacement approximately increases linearly with wind speed, and the mid-span response is higher than that of the side spans, showing significant spatial sensitivity to wind loads. Finally, the study shows that, although the system temperature difference causes small overall displacements, it still induces symmetrical lateral deformations and local stress concentrations near the closure segment. Local refined analyses further reveal the displacement distribution mechanism of the closure segment under operational loads. The health monitoring data agree well with the simulation results, validating the reliability of the numerical model. The research systematically reveals the spatial mechanical behavior of such bridges under operational loads, providing theoretical basis and engineering references for the design optimization and safety monitoring of similar asymmetric cable-stayed bridges. Full article

Soil quality assessment represents the essential step to achieve sustainable agriculture. This study introduces SUITED, a GIS-based approach that overcomes limitations of traditional soil quality indices by using open data, a remote sensing-derived salinity index, and a customized Water Quality Index (WQI) to evaluate soil quality, irrigation water quality, and treated wastewater use. The index was constructed by combining the selected factors across different soil depths and subsequently merging them using a weighted linear combination to produce the result map. Each parameter has been classified using geometrical criteria allowing a site-specific assessment. SUITED was applied to small sub-watersheds of the Volturno and Po rivers plains (southern and northern Italy, respectively). The index maps (0–30 cm depth) show that over 90% of both areas fall into medium to very low sustainability classes. In the Volturno river plain, soil quality is primarily driven by soil type distribution and their inherent heterogeneity, while in the Po river plain, soil texture and shallow saline groundwater mainly control sustainability. Furthermore, the integration of WQI and SUITED maps provided a reliable evaluation of irrigation water impacts, supporting informed decision making for water use and drainage management. Full article