Search Results (820)

Using panel data from 182 county-level cotton-growing regions in the Middle and Lower Reaches of the Yangtze River (2000–2022), this study investigates the drivers of cotton planting area contraction, focusing on the synergistic impacts of non-farm employment, agricultural policies, and their synergies, while verifying mechanisms via rural labor outflow and cotton economic returns. From a sustainability perspective, cotton planting area and output were relatively stable with fluctuations in 2000–2010, but plummeted by 80.6% and 82.8%, respectively, by 2022 (a “cliff-like” decline). Empirical results from the Spatial Durbin Model (SDM) show: (1) Non-farm employment significantly reduces local cotton cultivation and exhibits spatial spillover effects—counties neighboring or economically similar to regions with higher non-farm employment experience greater pressure for contraction; (2) This contraction is more pronounced in counties with smaller rural populations and lower cotton returns, confirming that labor scarcity and low profitability are key channels; (3) Agricultural policies exacerbate the decline: the 2005 Reward Policy for Major Grain-Producing Counties triggers cotton-to-grain substitution, while the 2014 shift from cotton temporary stockpiling to target price subsidies further accelerated the contraction of cotton cultivation in inland regions. This study contributes to understanding agricultural system transitions in the Yangtze River Basin, offering insights for optimizing sustainable planting structure adjustment and balancing food security with cash crop development under rural economic transformation. Full article

This study investigated the effects of vitamin E supplementation on growth performance, antioxidant capacity, and hepatic lipid metabolism in one-year-old juvenile Chinese sturgeon (Acipenser sinensis). A total of 270 fish (initial weight 1.37 ± 0.04 kg) were allocated into 9 fiberglass tanks and fed isonitrogenous and isolipidic diets with graded concentrations of vitamin E (DL-α-tocopherol acetate) including, 0, 1000, and 2000 mg/kg, respectively, for 2 months. Results showed that 1000 mg/kg vitamin E significantly improved growth performance and decreased hepatosomatic index. Dietary vitamin E supplementation significantly reduced the hepatic crude protein and crude lipid levels, withnot significantly affecting moisture and crude ash. Dietary vitamin E led to significant increases in plasma high-density lipoprotein cholesterol and vitamin E levels, while decreasing plasma low-density lipoprotein cholesterol. Additionally, it raised liver vitamin E content and reduced hepatic triglycerides, total cholesterol, crude protein, and crude lipid levels. Vitamin E also significantly downregulated mRNA levels of lipogenesis-related genes (ACC1, acetyl-CoA carboxylase 1; FASN, fatty acid synthase; and PPARγ, peroxisome proliferator activated receptor γ) and inhibited the enzyme activities of ACC1 and FASN, while upregulating lipolysis-related genes (HSL, hormone-sensitive lipase; CPT1, carnitine palmitoyltransferase 1α, and PPARα, peroxisome proliferator activated receptor α) and enhancing the activities of HSL and CPT1α. Furthermore, vitamin E supplementation significantly improved plasma reduced glutathione and superoxide dismutase activities, lowered plasma reactive oxygen species, malondialdehyde levels, and hepatic malondialdehyde contents, and upregulated mRNA levels of hepatic Nrf2 (nuclear factor-erythroid 2 related factor 2), Keap1 (Kelch-like epichlorohydrin associating protein 1), and CuZnSOD (copper/zinc superoxide dismutase). In conclusion, dietary 1000 mg/kg vitamin E supplementation could improve growth performance, enhance antioxidant capacity, and reduce liver fat deposition, indicating its potential as a beneficial dietary additive for promoting health and lipid regulation in juvenile Chinese sturgeon. Full article

The Wushan Loess, situated in the Yangtze Three Gorges region of China, represents the southernmost aeolian loess deposit in China and provides critical insights into Late Pleistocene paleoenvironmental conditions and East Asian monsoon dynamics. Despite its significance, the genesis and provenance of this unique loess deposit remain controversial. This study employs an integrated multi-proxy approach combining detrital zircon U-Pb geochronology, optically stimulated luminescence (OSL) dating, and detailed grain size analysis to systematically investigate the provenance and depositional mechanisms of the Wushan Loess. Three representative loess–paleosol profiles (Gaotang-GT, Badong-BD, and Zigui-ZG) were analyzed, yielding 17 OSL ages, 729 grain size measurements, and approximately 420 analyses per profile were conducted, yielding 1189 valid ages (GT 406, BD 391, ZG 402). OSL chronology constrains the deposition period to 18–103 ka (Marine Isotope Stages 2–5), coinciding with enhanced East Asian winter monsoon activity during the Last Glacial period. Grain size analysis reveals a dominant silt fraction (modal size: 20–25 μm) characteristic of aeolian transport, with coarse silt (20–63 μm) averaging 47.1% and fine silt (<20 μm) averaging 44.2% of the sediments. Detrital zircon U-Pb age spectra exhibit consistent major peaks at 200–220 Ma, 450–500 Ma, 720–780 Ma, and 1800–1850 Ma across all profiles. Kernel Density Estimation (KDE) and Multi-Dimensional Scaling (MDS) analyses indicate a mixed provenance model. Non-negative least squares (NNLS) unmixing confirms this quantitative source apportionment., dominated by proximal contributions from the upper Yangtze River basin (including the Three Gorges area and Sichuan Basin, ~65%–70%), supplemented by distal dust input from the Loess Plateau and northern Chinese deserts (~30%–35%). This study establishes for the first time a proximal-dominated provenance model for the Wushan Loess, providing new evidence for understanding southern Chinese loess formation mechanisms and Late Pleistocene East Asian monsoon evolution. Full article

The Energy–Economy–Environment (3E) nexus within basin economic zones has received significant scholarly attention. As a major river basin economic belt in China, the Yangtze River Economic Belt (YREB) serves as an important case for examining the status and drivers of coordinated 3E development. The findings of this study may also offer valuable insights for promoting sustainable development in river basin economies globally. Encompassing 11 provinces and municipalities, the YREB represents not only a vital socioeconomic region in China but also one of the nation’s largest energy consumers, facing considerable environmental pressures. Using panel data spanning 2009–2019, this study applies the coupling coordination degree (CCD) model, spatial Durbin model, and Moran’s I to assess the coordination level of the 3E system in the YREB. The main findings are as follows: (1) The CCD demonstrated a trend that was fluctuating but generally on the rise throughout the study period. Higher values were observed in eastern provinces and lower ones in western provinces, which reveals a distinct east–west spatial gradient. (2) A significantly positive spatial correlation was observed in provincial 3E coordination, although this correlation fluctuated and showed a slowly weakening trend over time. Local spatial clustering patterns also shifted, marked by the persistence of high-high clusters, an increase in low-low clusters, and the emergence of low-high outliers. (3) Estimates from the spatial Durbin model indicate that urbanization, automobile consumption, and foreign trade exert positive overall effects on the CCD, whereas industrial structure exerts a negative overall effect. Environmental policy is not statistically significant in the static model but shows a negative overall effect when the CCD is lagged by one period. Full article

The environmental persistence of sucralose (SUC), a recalcitrant artificial sweetener, has raised significant ecological concerns owing to its notable resistance to both thermal and biological degradation. This study focused on the eight major river basins in Zhejiang Province and used the LC-MS/MS external standard method to systematically detect the environmental occurrence of SUC. Significant spatial variations were observed. The highest concentration recorded in the river was 6.60 μg/L in the Beijing-Hangzhou Grand Canal. In contrast, the Ou River showed almost no detectable concentration. Higher contamination levels were consistently found in urban-adjacent areas, particularly near Hangzhou metropolitan region. Distinct seasonal patterns were also identified, with peak concentrations occurring during summer months. Through the application of the seasonal Kendall trend analysis, an increasing trend was projected for seven of the eight river systems studied, with the Ou River being the sole exception. Furthermore, the accuracy of the model’s prediction results was verified by comparing the data from the 2024 experimental tests with the model’s predicted results. By comparing the data from the experimental tests in 2024 with the model’s predictions, the results showed that, except for the Beijing-Hangzhou Grand Canal, the relative deviations of the other rivers were all less than 5.00%. This indicates that the model had a high accuracy in predicting the changing trend of concentrations. This study provided fundamental data for understanding sucralose’s environmental behavior in the Yangtze River Delta watersheds, serving as a critical baseline data for ecological risk assessments and contributing to water resource sustainability. And the ecological or toxicological implications of SUC pollution require further study. Furthermore, this study developed a transferable methodological framework for monitoring artificial sweetener contamination across diverse aquatic ecosystems. Full article

River–lake systems in the middle and lower reaches of the Yangtze River Basin function as critical ecological interfaces for maintaining regional water security and biodiversity. However, the complex interplay between environmental factors and biological communities in these systems remains poorly understood, limiting evidence-based management strategies essential for achieving sustainable development goals. This study investigated the spatiotemporal heterogeneity of environmental variables and their relationships with biological communities across 36 sampling sites (4 rivers, 5 lakes) from January to November 2022. Significant spatial differences were observed between river and lake systems, with lakes exhibiting higher concentrations of biochemical oxygen demand (BOD₅), chlorophyll-a, permanganate index (CODMn), loss on ignition (LOI), sediment total nitrogen (STN), total organic carbon (TOC), and turbidity, while rivers showed elevated total nitrogen levels. These patterns reflected fundamental differences in hydrodynamic mechanisms, particularly water retention time and sedimentation processes. Environmental parameters displayed distinct seasonal variations, with BOD₅ increasing markedly in autumn, and chlorophyll-a showing system-specific peaks in lakes (May) and rivers (September). Multivariate analyses revealed that water temperature, organic matter, and nutrients (particularly phosphorus) were key drivers shaping both phytoplankton and benthic communities. The structural equation model identified a strong cascade pathway from turbidity through phosphorus to phytoplankton richness, and uncovered a “phosphorus paradox” wherein total phosphorus exhibited contrasting effects on different biological components—positive for phytoplankton richness but negative for benthic richness. The positive relationship between phytoplankton and benthic macroinvertebrate richness provided evidence for benthic–pelagic coupling in this river–lake system. These findings advance our understanding of the complex mechanisms linking physical factors, nutrient dynamics, and biological communities across river–lake continuums, providing a quantitative framework for ecosystem-based management that supports sustainable development in the Yangtze River Basin and similar freshwater systems globally. Full article

The analysis of changing trends of river runoff and sediment discharge and the exploration of their causes are of great significance for formulating sustainable development measures for river basin systems. Based on methods such as trend test, mutation detection, and regression analysis, this study conducts a systematic comparative research on the water–sediment processes in the river reach where large-scale cascaded reservoirs connected end to end are located in the upper Yangtze River, and obtains the following key research progress: For the study reach (between Sanduizi and Xiangjiaba Stations), during the period of 1966–2023, the change rates of annual incoming and outgoing runoff were 2.88 × 10⁸ m³·yr⁻¹ and −0.186 × 10⁸ m³·yr⁻¹, respectively, accounting for 0.017% and 0.013% of the annual average runoff. The changing trends were not significant. During the same period, the change rates of Suspended Sediment Load (SSL) at the inlet and outlet of this river reach were −8.0 × 10⁵ t·yr⁻¹ and −46 × 10⁵ t·yr⁻¹, respectively, accounting for 1.25% and 2.45% of their respective annual average sediment discharge. The SSL showed a significant decreasing trend, which was particularly characterized by a sharp reduction at the outlet. The massive sediment retention and multi-mode operation of cascaded reservoirs are the fundamental reasons for the variation in the water–sediment relationship and the sharp decrease in annual SSL in this reach, and they also lead to an obvious adjustment of water and sediment in the river basin that “cuts peaks and fills valleys” within a year. Climate change and other human activities have reduced the sediment input in the study reach. Looking forward to the next few decades, climate factors will remain the dominant factor affecting the inter-annual variation in runoff in the study area. In contrast, human activities such as reservoir operation will continue to fully control the sediment output of the river reach and also restrict the annual distribution of water and sediment. The results of this study can provide a reference for predicting the changing trends of water and sediment in similar river reaches with cascaded reservoir groups and formulating effective river management measures. Full article

The Yangtze River Basin serves as the socioeconomic core of China, and rapid development in recent years has intensified the conflict in the area between economic growth and ecological conservation. This study evaluated the spatiotemporal evolution of the land ecological security (LES) across 11 provinces and municipalities in the Yangtze River Basin from 2008 to 2023 by using the framework of the drivers, pressures, state, impact, and response model of intervention. We forecasted the trends of LES (2024–2033) by using a grey prediction model and identified the key obstacles to it through an obstacle degree model. The findings revealed the following: (1) Economic density (D3) and per capita water resources (S4) had significantly high weights, disproportionately impacting LES. Shanghai scored highest for Drivers, Impact, and Response subsystems, while Tibet led in Pressures and State. (2) Basin-wide LES scores improved from “less safe” to “critical safe” but saw no fundamental breakthrough. LES exhibited a three-tier spatial pattern: higher in the middle-lower reaches (e.g., Shanghai, Jiangsu) and lower in the upper reaches (e.g., Qinghai). Tibet remained “critical safe” with minor fluctuations; other regions improved gradually yet mostly remained “less safe” or “critical safe”. (3) Forecasts (2024–2033) indicate continued overall LES improvement. Shanghai and Jiangsu are projected to reach “safe” status, Qinghai will remain “unsafe”, while most others persist as “critical safe”. Basin LES remains fragile, requiring intervention. (4) The Drivers (D) and State (S) subsystems were the primary constraints on LES. Critical obstacle indicators included economic pressure (per capita GDP (D2), D3), resource availability (S4, ratio of effectively irrigated area (I1)), land productivity (agricultural/forestry output per unit area (I3)), and forest coverage rate (R6). Enhancing LES necessitates implementing regionally tailored policies addressing spatial variations, prioritizing urban economic optimization, strengthening water resource management, and ensuring effective cross-regional governance. Full article

Direct seeding of winter rapeseed in the Yangtze River Basin often coincides with low temperatures during establishment. The aim of this study was to test whether low-temperature (LT) germination performance predicts overwintering survival and yield under delayed sowing. Thirty accessions were evaluated in controlled germination at 20/14 °C (CK) and 12/6 °C (LT) and in two field seasons (2020–2021 and 2021–2022), with six sowing dates from 15 October to 4 December. Mean germination rate was 97.6% in CK and 88.0% in LT. Germination potential (GP) averaged 95.7% in CK and 41.9% in LT. Root and shoot length decreased from 7.63 and 5.02 cm in CK to 1.47 and 0.48 cm in LT. Overwintering survival declined with later sowing. In the colder season (2020–2021), survival for sowings after November fell below 20% for most accessions, whereas S1–S2 averaged above 80%. Yield decreased with delay. In 2021–2022, yield under S1 exceeded S2–S6 by 5.5%, 8.5%, 13.9%, 14.0%, and 23.3%. In 2020–2021, S1 was similar to S2, but 6.3–22.8% higher than S3–S6. Thousand-seed weight followed the same trend. LT GP and LT root length were positively correlated with yield at several sowing dates in the colder season, indicating that LT germination traits are predictive of late-sown performance under harsher winters. Seven accessions (3409, M417, Zheza0903, 86155, 3445, Zheyou50, and 3462) showed superior LT germination and comparatively better field performance. For the lower Yangtze site, a practical latest safe sowing window is late October, based on two seasons; November sowing substantially increases winter mortality and yield risk. Selecting genotypes with strong LT germination and managing for rapid autumn establishment can stabilize 1000-seed weight and yield when sowing is delayed. Full article

Odontobutis potamophila, a small benthic carnivorous fish endemic to the Yangtze River basin, holds considerable ecological and commercial value. However, overfishing and habitat degradation have led to a severe decline in its wild population. A lack of quantitative reproductive data has further hampered effective conservation and resource management. To address this, we conducted monthly sampling, collecting a total of 894 individuals from Nansi Lake between August 2017 and July 2018. By integrating gonadal histological staging, gonadosomatic index (GSI) analysis, logistic regression, and fecundity assessments, we provide a foundational understanding of the species’ reproductive biology. The annual sex ratio was 1.06:1, with a temporary female bias in April (2.14:1) shifting due to male nest-guarding behavior. Both sexes reached maturity at one year and approximately 73.6 mm in length. Spawning occurred from March to June, peaking in May (GSI = 28.92%). Absolute fecundity ranged 2306 ± 1430 eggs and correlated positively with body size and age, while relative fecundity stabilized after age two. Individuals aged two years and older contributed over 80% of total egg production, reflecting a strategy of early maturation with high reproductive output at older ages. This study aims to systematically understand the reproductive biology of O. potamophila. These results support science-based measures such as Covering the entire window from gonadal maturation to fry dispersal, an annual fish ban established from March to June, a minimum catch size of 80 mm, and improved broodstock management for aquaculture and conservation efforts aimed at this and related benthic fishes in shallow lake ecosystems. Full article

The impact of climate change on watershed hydrological processes has become increasingly significant, with the frequent occurrence of extreme flood events posing a severe challenge to the water resource security of the upper Yangtze River and the Three Gorges Reservoir. To enhance the understanding of runoff evolution under future climate scenarios, this study focuses on the upper Yangtze River Basin, integrating CMIP6 climate model data with the WRF-Hydro model to systematically assess the effects of climate change on runoff projections. Firstly, using CMFD data as a benchmark, the systematic biases in CMIP6 simulation results were evaluated and corrected. Precipitation and temperature data accuracy were improved through Local Intensity Correction (LOCI) and Daily Bias Correction (DBC). Secondly, a large-scale WRF-Hydro model suitable for the upper Yangtze River was developed and calibrated. Finally, based on the corrected CMIP6 data, the climate and runoff changes under the SSP2-4.5 and SSP5-8.5 scenarios for the period 2021–2050 were projected. The results show that: (1) the corrected CMIP6 data significantly improved issues of overestimated precipitation and underestimated temperature, providing a more realistic reflection of regional climate characteristics; (2) the sub-basin calibration strategy outperformed the overall calibration strategy at key control sites, with high runoff simulation accuracy during the validation period; (3) future temperatures exhibit a continuous rising trend, while precipitation changes are not significant—however, the magnitude and uncertainty of extreme events increase—and (4) under the SSP5-8.5 scenario, the inflow to the Three Gorges Reservoir during the wet season significantly increases, raising flood risk. The findings provide a scientific basis for understanding the hydrological response mechanisms in the upper Yangtze River Basin under climate change and offer decision-making support for flood control scheduling and water resource management at the Three Gorges Reservoir. Full article

The sediment yield resulting from storm erosion has become a focal point of research and a significant area of interest in the upper reaches of the Yangtze River amid changing environmental conditions. The issue of numerous types of erosivity factors (R) in storm erosion sediment yield models, with unclear applicability. This study examines two classical types of erosivity factors: the rainfall erosivity factor (EI₃₀, Zhang Wenbo empirical formula, etc.) and runoff erosivity power. Four combinatorial forms of erosion dynamic factors, encompassing rainfall and runoff elements, were developed. Based on the rainfall, runoff and sediment data of four stations along the Fu River basin–Pingwu station, Jiangyou station, Shehong station and Xiaoheba station from 2008 to 2018, the correlation between different R factors and sediment transport in different watershed areas was studied, and the semi-monthly sediment transport model of heavy rainfall in the Fu River basin was constructed and verified. The results revealed a weak correlation between the rainfall erosivity factor and the sediment transport modulus, making it unsuitable for developing a sediment transport model. In smaller basin areas, the correlation between the combined erosivity factor and sediment transport modulus was strongest; conversely, in larger basins, the relationship between runoff erosivity power and the sediment transport model was most pronounced. The power function relationship between the erosivity factor and sediment transport modulus yielded a more accurate simulation of sediment transport during the verification period, particularly during rainstorms, surpassing that of SWAT. These findings provide a scientific basis for predicting sediment transport during storms and floods in small mountainous basins. Full article

The Yangtze River fishing ban policy is a central measure in China’s watershed governance, and the adaptability of its policy tools and collaborative mechanisms directly influences the sustainability and effectiveness of basin management. This study systematically examines the evolution of policy themes, the characteristics of policy tool combinations, and their alignment with intergovernmental collaborative governance needs, drawing on 120 central government policy texts issued between 2002 and 2024. Using frequency analysis and policy tool coding, the findings reveal that (1) policy themes have shifted from fishery resource control to comprehensive ecological protection and, more recently, to integrated watershed management, thereby driving progressively higher demands for intergovernmental collaboration. (2) The policy tool structure has long been dominated by environmental tools, supplemented by supply-side tools, while demand-side tools remain underdeveloped. Imbalances persist, such as excessive emphasis on resource inputs over capacity building in supply-side tools, rigid constraints with limited flexibility in environmental tools, and a reliance on publicity while underutilizing market incentives in demand-side tools. (3) Tool combinations have adapted to changing collaboration needs, evolving from rigid constraints and fiscal subsidies to institutional frameworks and cross-regional cooperation, ultimately forming a governance model characterized by systemic guarantees and diversified collaboration. Based on these findings, this study recommends strengthening long-term governance mechanisms, improving cross-regional collaborative structures, authorizing local governments to design context-specific implementation details, enhancing fishermen’s livelihood security and social development, expanding public participation and oversight, and exploring market mechanisms for realizing ecological product value. These measures aim to advance collaborative governance in the Yangtze River Basin and foster a balanced integration of ecological protection and social development. Full article

China’s Yangtze and Yellow River Basins exhibit divergent drought patterns, yet the underlying mechanisms driving these differences remain underexplored. This study compares their drought characteristics from 1961 to 2022 using the Standardized Precipitation Index, Standardized Precipitation Evapotranspiration Index, and Palmer Drought Severity Index, and identifies their drivers through attribution models and interpretable machine learning. Our results reveal two distinct paradigms: the Yangtze Basin is characterized by high-frequency, over 14% in all seasons, short-duration droughts, reflecting a rapid hydrological response, while the Yellow River Basin experiences low-frequency, long-duration events indicative of strong soil moisture memory. Quantitative attribution demonstrates that atmospheric evaporative demand (VPD) plays a significantly greater role in the Yellow River Basin, contributing over 20% to soil drought, far exceeding its 14.4% contribution in the Yangtze Basin. Furthermore, their large-scale drivers differ fundamentally: the Yangtze Basin responds primarily to the Atlantic Multidecadal Oscillation (AMO) and Arctic Oscillation (AO), whereas the Yellow River Basin is mainly influenced by solar activity and the El Niño-Southern Oscillation (ENSO). These findings reveal that Yangtze drought is primarily driven by precipitation deficits, while Yellow River drought is a composite phenomenon amplified by evaporative demand. This distinction underscores the need for basin-specific water management strategies. Full article

This study evaluates the pollution status, ecological risks, health risks, and sources of heavy metals from farmland in a mining city located in the Yangtze River basin, East China. A total of 2361 samples of topsoil were collected and analyzed for the concentration of five heavy metals and pH. The Nemerow index was used to assess integrated pollution, while absolute principal component scores-multiple linear regression (APCS-MLR) was used to identify the sources of heavy metals. The results revealed that, excluding Hg and Cr, the concentrations of Cd, As, and Pb in some samples exceeded intervention values, with Cd concentrations in 19.7% of samples surpassing this threshold. Based on the Nemerow index, 68.8% of sites were contaminated, with 27.4% classified as heavily polluted, indicating significant pollution in this area. Cd posed the primary ecological risk, with 19.8% of sites at high risk or above, also presenting carcinogenic risks to adults. Additionally, As exceeded safety thresholds for hazard quotient (HQ = 1) and carcinogenic risk (CR = 1 × 10⁻⁴). APCS-MLR revealed that heavy metals in farmland were mainly influenced by mining, agricultural activities, and natural soil-forming processes. This study offers insights into farmland heavy metal management and highlights industrial pollution sources in mining areas. Full article