Search Results (170)

In the past two decades, little information has been updated to understand the resource status of the crab species Ovalipes punctatus in the East China Sea Region. In this study, we conducted surveys in 2018 and 2019 to identify the seasonal spatial distribution patterns of the economically important sand crab Ovalipes punctatus (De Haan 1833) in the southern Yellow and East China Seas. In the study area, the largest biomass of crabs was observed in the fishing grounds of Dasha and the Yangtze River mouth, and the second largest biomass was detected in the Jiangwai-Zhouwai area. Seasonally, the total biomass order in these areas was summer > autumn & winter > spring, and the mean average individual weight order was spring & summer > winter > autumn. These findings provided maps of the seasonal spatial distribution pattern of the species across seasons, which were then used in climate-change scenario models. Model predictions suggested that O. punctatus might migrate northward and offshore under climate warming conditions, and that the climate scenario SSP585-2100 might be the most negative case, respectively, for the habitat area of gain% minus loss%. These data can be used to develop robust and systematic regional fisheries resource management policies that consider adaptation measures to address the impact of environmental and climate change along China’s coasts and other areas in the world. Full article

As the world’s third-longest river supporting 40% of China’s population, the Yangtze River Basin exemplifies the critical challenges of balancing riparian development and ecological resilience for major fluvial systems globally. This study analyzed the spatiotemporal evolution, proximity dynamics to the Yangtze River, and driving mechanisms of the “three types of spaces” (urban, agricultural, and ecological) in 130 counties along the Yangtze River mainstem from 2000 to 2020, utilizing an integrated approach incorporating land use transfer matrices, centroid-based distance metrics and GeoDetector models. Key findings reveal: (1) Urban space exhibited significant irreversible expansion while agricultural space continued to shrink, with ecological space maintaining overall stability but showing high-frequency bidirectional conversion with agricultural areas in localized zones. (2) Spatial proximity analysis demonstrated contrasting patterns—eastern riparian counties showed urban spatial agglomeration towards the river, whereas most mid-western regions experienced urban expansion away from the watercourse, with marked regional disparities in agricultural and ecological spatial changes. (3) Driving mechanism analysis identified topography as the dominant natural factor influencing ecological space evolution, while socioeconomic factors exerted stronger impacts on proximity variations of agricultural and urban spaces, with natural–socioeconomic interactive effects showing the most significant explanatory power. These spatial dynamics reflect universal trade-offs between economic development and ecosystem conservation in large river basins worldwide. We advocate differentiated spatial governance strategies, including rigorous riparian ecological redlines, eco-agricultural models in agricultural retreat zones, and proximity-based real-time monitoring for ecological early warning. The integrated methodology and spatial governance framework offer transferable solutions for sustainable management of major fluvial systems under rapid urbanization pressure. These findings provide scientific evidence and implementable pathways for coordinating socioeconomic development with ecosystem resilience in the Yangtze River Economic Belt. Full article

Camellia oleifera Abel (C. oleifera) is an evergreen shrub classified under the Camellia genus. It is an important oil species and has great economic benefits. At present, C. oleifera is widely cultivated in the Yangtze River Basin in South China, and its wild species are mainly distributed in the native forests of Hainan Province. Therefore, in the current study, we used the MaxEnt model to predict the suitable habitat for C. oleifera and different environmental factors affecting its current and future distribution. The AUC values exceeded 0.98, showing that the simulation of the model was good, and the TSS values were all above 0.96, indicating that the model was feasible. The results showed that C. oleifera was mainly distributed in Southern China, with a total area of 56.68 × 10⁴ km². The suitable habitats of Camellia oleifera are affected by the precipitation of the warmest quarter (bio18), human activity, soil available water content (awc_class), and minimum temperature of the coldest month and seasonal temperature (bio04). Furthermore, rainfall in the warmest quarter (bio18) was recognized as a crucial factor impacting its distribution. Under future climate conditions, the suitable habitat area of C. oleifera is projected to expand with a slight northward shift in its distribution center. Therefore, in addition to maintaining the current planting area of C. oleifera, the planting area can be appropriately expanded upward along the current area and along the Yangtze River Basin. Full article

In this study, we investigate the impact of soil moisture at varying depths on the stability of Chinese ecosystems, with ecosystem stability assessed using the Enhanced Vegetation Index (EVI) and Gross Primary Productivity (GPP). A multi-perspective analysis is conducted across different climatic zones and land cover types. Sen’s Slope Estimation and the Mann–Kendall trend test, combined with linear regression and correlation analyses, are employed to analyze the long-term trends of EVI and GPP in different climatic zones and land cover types and to assess the effects of soil moisture changes on ecosystem stability. The research reveals the following findings: (1) On a national scale, both EVI and GPP exhibit positive growth trends, with more significant increases in humid areas and relatively slower growth in arid areas. In addition, EVI and GPP of different land cover types exhibit positive inter-annual variation trends, reflecting a gradual enhancement in ecosystem productivity. (2) Cluster analysis shows that EVI has strong spatial correlation, with a distribution pattern of low–low (L-L) clusters in the north and high–high (H-H) clusters in the south. L-H clusters are concentrated in the Huaihai, Southwest Rivers, and Pearl River basins, while H-L clusters are scattered along the eastern coast. The spatial correlation of GPP is mainly concentrated in the south and the northeast, with a distribution pattern of L-L in the northeast, L-H in the Yangtze River basin, and H-H in the south. H-L clusters are dispersed in the downstream area of the Yangtze River. Both EVI and GPP show a tendency for high-value aggregation in space, with high-value areas of EVI located in the south and low-value areas in the central and western regions. High-value areas of GPP are in the south, while low-value areas are in the northeast, particularly in the Yangtze River Delta. (3) The correlation between EVI, GPP, and soil moisture varies significantly across different climatic regions. Arid and semi-humid regions show significant correlations between specific soil moisture depths and EVI and GPP, while such correlations are not significant in humid regions. The EVI and GPP values of croplands and grasslands are significantly and negatively correlated with soil moisture at depths of 150–200 cm (SM4). Conversely, wetland GPP values increase significantly with increasing soil moisture. Other vegetation types do not show significant correlations with soil moisture. The results of this study provide an important basis for understanding the impact of climate change on ecosystem stability and offer scientific guidance for ecological protection and water resource management. Full article

When the shield machines are constructed in soft soil, excavation may be impeded by the accumulation of cutter head mud. Geological conditions and shield construction are identified as the main factors for cutter head mud formation, based on analysis of its mechanism. In addition to traditional metrics, the imperforation area in the cutter head center is incorporated into the analysis of shield construction factors. The Analytic Hierarchy Process (AHP) is utilized to establish a risk assessment model for shield cutter head mud cake, determining the weight of each sub-factor and enabling a preliminary risk assessment of mud cake occurrence. This study applies Analytic Hierarchy Process (AHP) to classify the factors affecting shield mud by using the Mawan cross-sea channel construction project (Moon Bay Avenue along the Yangtze River) as a case study. Each factor is scored and weighted according to established scoring criteria and evaluation formulas, and then the results of the risk of shield mud cake in the Mawan tunnel are obtained. Moreover, field observations validate the proposed risk model, with the derived risk index demonstrating strong alignment with actual data. Full article

Reducing fertilizer and pesticide use is a crucial path for the green transformation of agricultural production, which has garnered sustained attention in research on sustainable agricultural development. Based on the theoretical analysis, this article analyzes the spatiotemporal evolution characteristics of fertilizer and pesticide usage intensity (FUI and PUI) in the Yangtze River Delta (YRD) over the past 20 years and uses a Two-Way Fixed Effects Model to test their impacts and mechanisms. Findings show that agricultural development in the YRD shows a pattern of specialization and intensification with a significant north–south divide, with zero growth and reduction in fertilizer and pesticide use across the region from 2010 to 2015, but the current FUI and PUI are still nearly three and five times higher than the global average. Over the past 20 years, the FUI is high in the north and low in the south, high in the plains and low in mountainous-hilly areas, and high in suburban areas and low in remote counties. Adversely, the PUI is high in the south and low in the north, high in mountainous-hilly areas and low in plains, and high in suburban areas and low in remote counties. The FUI and PUI of characteristic agricultural areas of fruit, tea, and forestry in southern Anhui and southwestern Zhejiang, as well as the agroecological and facility agriculture clusters in southern Jiangsu and the suburbs of Shanghai, have approached the peak and successfully moved into the new green development stage earlier compared to other areas. In contrast, the grain and oil production plains areas along the Yangtze River, the coast, in northern Anhui, and in northern Jiangsu are relatively lagging behind. The combination of soil, water, light, and heat resource conditions and modes of agriculture production shape the absolute figures of FUI and PUI, and factors such as the level of local economic development and public fiscal expenditure significantly influence the trajectories of spatiotemporal differentiation in the progress of reducing fertilizer and pesticide in the YRD. Full article

Under increasingly stringent global policies aimed at reducing emissions from shipping, the impact of maritime activities on air quality has garnered significant attention. However, the absence of comprehensive macro-evaluation methods and a limited understanding of regional-scale pollutant emissions introduce substantial uncertainties in assessing emission reduction effectiveness and identifying pollution sources. In this study, we utilized Sentinel-5P satellite data from 2019 to 2024 to examine the spatiotemporal characteristics of six air pollutants (SO₂, NO₂, HCHO, O₃, CO, and CH₄) in China’s coastal areas. We further investigated the correlation between ship density and pollutant concentrations and analyzed the distribution of pollutant concentrations in major coastal ports across China. The results indicate the following: (1) The concentrations of SO₂, HCHO, and CH₄ exhibited a continuous increasing trend, whereas NO₂, CO, and O₃ remained relatively stable or showed a slight decline. All six pollutants demonstrated obvious seasonal variations, with NO₂ and HCHO following a double-peak pattern and O₃, SO₂, CH₄, and CO exhibiting a single-peak pattern. (2) Pollutant concentrations were higher along the northern coast (Yellow Sea and Bohai Sea) and relatively lower in the South China Sea region. Specifically, NO₂, SO₂, and O₃ were higher in the Bohai Sea region; HCHO and CO were more concentrated in the northern coastal area; and CH₄ was elevated in the north and certain ports of the Yangtze River Delta. (3) Ship density displayed a significant positive correlation with NO₂, SO₂, HCHO, CO, and CH₄, indicating that ship emissions are an important source of these pollutants. Although O₃ is not directly emitted by ships, a positive correlation was observed in certain ship-dense areas, primarily due to photochemical reactions involving NO₂ and volatile organic compounds (VOCs). (4) Higher concentrations of NO₂, SO₂, HCHO, CO, and CH₄ were observed in northern ports (e.g., Tianjin Xingang, Qinhuangdao, Tangshan, and Dalian), whereas southern Chinese ports (e.g., Shenzhen, Xiamen, and Haikou) exhibited lower pollution levels. These findings provide a scientific foundation for coastal air pollution control and highlight the necessity of ship emission regulation and integrated multi-pollutant management. Full article

As an important ecological barrier in the upper reaches of the Yangtze River, the Jialing River Basin has complex and sensitive hydrochemical evolutionary mechanisms due to its geological structures and human activities. This study focuses on the groundwater in the Wusheng section of the Jialing River Basin, combining field investigations and Entropy-Weighted Water Quality Index (EWQI) calculations to analyze its hydrochemical characteristics and influencing factors and conduct a water quality assessment. The results show that this regional water body has a pH of 7.05–8.36, presenting weakly alkaline and low-mineralization characteristics, with differences in hydrochemical components between groundwater and surface water. The ions are predominantly controlled by rock weathering, with reactions such as halite and gypsum dissolution occurring during groundwater runoff. Groundwater in the tectonic influence zone exhibits abnormal chemical compositions due to lateral recharge from different strata along fracture channels and long-distance runoff reactions with the surrounding rocks. EWQI values for groundwater range from 6.07 to 104.02, with an average value of 37.46, generally exhibiting a trend of increasing EWQI values near the Jialing Riverbank. In this area, 96.15% of groundwater meets excellent or good quality standards and is suitable for direct drinking. The influence of the intensity of different indicators on groundwater quality decreases in the order of Ca²⁺ > Cl⁻ > Mg²⁺ > SO₄²⁻ > HCO₃⁻ > NO₃⁻. Water quality is primarily influenced by the primary geological background, while agricultural practices may also lead to its deterioration. Full article

In the urgent context of global climate change and carbon neutrality goals, effective carbon balance regulation is critical for achieving temperature control targets. Metropolitan areas encounter significant challenges in carbon emission reduction, energy transition advancement, and enhancement of sequestration capabilities. However, traditional carbon balance analysis methods have limitations in capturing dynamic changes and guiding precise regulation. Therefore, this study developed a dynamic–static classification system for carbon balance based on the Ecological Support Coefficient (ESC) and the Economic Contributive Coefficient (ECC). This system examined carbon emissions and carbon sequestration in China’s 14 national-level metropolitan areas from 2000 to 2020. The results showed that: (1) Carbon emissions showed an increasing trend, exhibiting a spatial distribution with higher levels in the north, moderate levels in the central region, and the lowest levels in the southeast. In contrast, carbon sequestration exhibited a spatial pattern with higher levels in the east, moderate levels in the central region, and lower levels in the west. (2) Static classification revealed that the ECC and ESC of metropolitan areas in the central and northern regions were relatively weaker than those in other regions. Dynamic classification further showed an upward trend in the economic and ecological capabilities of these central and northern metropolitan areas. In contrast, metropolitan areas along the coast and within the Yangtze River Economic Belt needed to optimize their economic–ecological coordination efficiency. Although southern coastal metropolitan areas demonstrated robust economic vitality, they encountered significant ecological support pressures. (3) Economic development level and ecological environmental quality were the predominant factors in metropolitan area classification. Regions with a higher ECC tended to exhibit an enhanced ESC, while regions with a stronger ESC prioritized economic growth. This classification system provided a solid scientific basis for formulating differentiated low-carbon transformation strategies, thereby supporting high-quality development in China’s metropolitan areas while maintaining a dynamic balance between economic and ecologic objectives. Moreover, it offered both theoretical foundations and practical guidance for optimizing sustainable development pathways in similar metropolitan areas globally. Full article

Large reservoir-induced landslides pose a persistent threat to the safety of the Three Gorges Project and the Yangtze River shipping channel. A comprehensive multi-field monitoring system has been established to observe potential landslide areas within the Three Gorges Reservoir Area. The tasks of effectively utilizing these extensive datasets and exploring the underlying correlation among various monitoring objects have become critical for understanding landslide movement patterns, assessing stability, and informing disaster prevention measures. This study focuses on the No. 1 riverside sliding mass of the Huangtupo landslide, a representative large-scale landslide in the Three Gorges Area. We specifically analyze the deformation characteristics at multiple monitoring points on the landslide surface and within underground tunnels. The analysis reveals a progressive increase in deformation rates from the rear to the front and from west to east. Representative monitoring points were selected from the front, middle, and rear sections of the landslide, along with four hydrological factors, including two reservoir water factors and two rainfall factors. These datasets were classified using the K-means clustering algorithm, while the FP-Growth algorithm was employed to uncover correlations between landslide deformation and hydrological factors. The results indicate significant spatial variability in the impacts of reservoir water levels and rainfall on the sliding mass. Specifically, reservoir water levels influence the overall deformation of the landslide, with medium-to-low water levels (146.32 to 163.23 m) or drawdowns (−18.70 to −2.16 m/month) accelerating deformation, whereas high water levels (165.37 to 175.10 m) or rising water levels (4.45 to 17.33 m/month) tend to mitigate it. In contrast, rainfall has minimal effects on the front of the landslide but significantly impacts the middle and rear areas. Given that landslide deformation is primarily driven by periodic fluctuations in reservoir water levels at the front, the movement pattern of the landslide is identified as retrogressive. The association rules derived from this study were validated using field monitoring data, demonstrating that the data mining method, in contrast to traditional statistical methods, enables the faster and more intuitive identification of reservoir-induced landslide deformation patterns and underlying mechanisms within extensive datasets. Full article

Spanning China’s eastern, central, and western regions, the Yangtze River Economic Belt (YREB) is a pivotal area for economic growth and carbon emissions, with its three major urban agglomerations serving as key hubs along the upper, middle, and lower reaches of the Yangtze River. Understanding the driving factors of carbon emissions and simulating carbon peak scenarios in these regions are critical for informing low-carbon development strategies across China’s diverse geographical zones. This study employs Grey Relational Analysis to identify key drivers and applies the Logarithmic Mean Divisia Index (LMDI) decomposition method to quantify the contributions of various factors to carbon emissions from 2005 to 2021. Furthermore, the STIRPAT (Stochastic Impacts by Regression on Population, Affluence, and Technology) model is utilized to project future emission trends under multiple scenarios. The results indicate that (1) the growth rate of carbon emissions in the three urban agglomerations has generally decelerated during the study period; (2) the influence of driving factors varies significantly across regions, with economic development, urbanization, and population size positively correlating with carbon emissions, while energy structure and energy intensity exhibit mitigating effects; and (3) tailored emission reduction strategies for each urban agglomeration—namely, the Yangtze River Delta Urban Agglomeration (YRD), the Middle Reaches of the Yangtze River Urban Agglomeration (TCC), and the Chengdu-Chongqing Urban Agglomeration (CCA)—can enable all three to achieve carbon peaking by 2030. These findings provide a robust foundation for region-specific policy-making to support China’s carbon neutrality goals. Full article

As global climate change intensifies, its impact on the ecological environment is becoming increasingly pronounced. Among these, land surface temperature (LST) and vegetation cover status, as key ecological indicators, have garnered widespread attention. This study analyzes the spatiotemporal dynamics of LST and the Kernel Normalized Difference Vegetation Index (KNDVI) in 11 provinces along the Yangtze River and their response to climate change based on MODIS Terra satellite data from 2000 to 2020. The linear regression showed a significant KNDVI increase of 0.003/year (p < 0.05) and a LST rise of 0.065 °C/year (p < 0.01). The Principal Component Analysis (PCA) explained 74.5% of the variance, highlighting the dominant influence of vegetation cover and urbanization. The K-means clustering identified three regional patterns, with Shanghai forming a distinct group due to low KNDVI variability. The Generalized Additive Model (GAM) analysis revealed a nonlinear LST–KNDVI relationship, most evident in Hunan, where cooling effects weakened beyond a KNDVI threshold of 0.25. Despite a 0.07 KNDVI increase, high-temperature areas in Chongqing and Jiangsu expanded by over 2500 km², indicating limited LST mitigation. This study reveals the complex interaction between LST and the KNDVI, which may provide scientific basis for the development of regional ecological management and climate adaptation strategies. Full article

The coordination between poverty alleviation and ecological protection is both a crucial requirement and a long-standing challenge for sustainable development. China’s implementation of a targeted poverty alleviation strategy has completed the task of eliminating extreme poverty. However, the evaluation of the corresponding ecosystem changes in the entire poverty-alleviated areas is still insufficient. This study investigated the spatiotemporal changes in ecosystem vulnerability across China’s 832 national poverty-stricken counties from 2005 to 2020. A habitat–structure–function framework was applied to develop an evaluation index, along with a factor analysis of environmental and socio-economic indicators conducted through the Geodetector model. Finally, the implications of China’s practices to balance poverty alleviation and ecological protection were explored. The results show that ecosystem vulnerability decreased from 2005 to 2020, with an even greater decrease observed after 2013, which was twice the amount of the decrease seen before 2013. The post-2013 changes were mainly brought about by the enhancement of the ecosystem function in critical zones such as the Qinghai–Tibet Plateau Ecoregion, Yangtze River and Sichuan–Yunnan Key Ecoregion, and Yellow River Key Ecoregion. From 2013 to 2020, the influence of the gross domestic product (GDP) surpassed that of other factors, playing a significant positive role in diminishing ecosystem vulnerability in the three regions mentioned. The results suggest that China’s poverty-alleviated areas have found a “win–win” solution for poverty alleviation and ecological protection, that is, they have built a synergistic mechanism that combines government financial support with strict protection policies (e.g., more ecological compensation, eco-jobs, and ecological public welfare positions for poor areas or the poor). These findings elucidate the mechanisms behind China’s targeted poverty alleviation outcomes and their ecological implications, establishing a practical framework for coordinated development and environmental stewardship in comparable regions. Full article

The frequent occurrence of flooding disasters threatens urban public safety and sustainable development, making enhancing urban ecological resilience crucial for flood prevention and disaster reduction. This study, focusing on the Yangtze River Delta urban agglomeration (YRD) in China, constructs an evaluation framework based on three subsystems: the hazard, disaster-formative environment, and exposure. Using the entropy weight method, Geographic Information Systems (GIS), along with spatial autocorrelation analysis, the spatial distribution and trend of resilience indices are obtained. Based on stepwise regression analysis, the factors influencing the resilience distribution are discussed. The results show an overall increase in resilience levels in the YRD urban agglomeration, reflecting improvements in the urban emergency response and recovery capabilities. However, significant differences exist between cities, with a trend of decreasing resilience from first-tier cities to surrounding areas. Among these, indicators such as per capita disposable income and the number of people covered by social insurance have a significant positive impact on resilience clustering, highlighting the key role of socioeconomic vitality in urban resilience. This study is of great significance for differentiated and scientific flood disaster management in urban agglomerations. Full article

The contradiction between ecological environment protection and economic development in the Yangtze River Basin has become increasingly prominent in recent years, which seriously limits the sustainable development of the basin. Research on water environment changes of the main tributaries of the Yangtze River helps explore measures to improve the ecological environment of the Yangtze River Basin. In this study, based on the theory of behavioral science in modern management, water quality data in the field were collected, and the farmers’ garbage stacking behavior was also investigated in the water source area of the Dabie Mountains. The results showed that ammonia nitrogen (AN), chemical oxygen demand (COD), total organic carbon (TOC), and total dissolved solids (TDS) in the water bodies showed an overall negative correlation with the distance of water quality collection sites from the garbage stacking point. AN was the most important pollution element affecting the rural water quality in the water source area of the Dabie Mountains. The unsuitable garbage stacking locations and the farmers’ behavior of dumping garbage along the riverbanks were the important causes of water pollution. The garbage stacking locations were optimized and designed by using a GIS spatial analysis tool and a developed suitability evaluation model for the garbage stacking points. The optimized garbage stacking locations were more suitable for improving the local water environment, and their average suitability values increased to 2.01 times and 2.94 times that of the original stacking locations in Kanxiawan and Lengshuigou, respectively. This study can be used as a scientific and methodological reference for improving the rural water environment in the water source area of the Dabie Mountains and in other similar regions in the world. Full article