Yangcheng Lake is the third largest freshwater lake on the Taihu Plain.Based on the monthly monitoring data of water quality of Yangcheng Lake from 2019 to 2023 and the field survey data of water environment in flood seasons in 2023, this paper analyzed the temporal and spatial variation of water quality in flood seasons.The causes of pollution was also analyzed from the perspectives of exogenous input, endogenous release and pollution reduction of aquatic vegetation.The results showed that the water quality of the Lake in the flood seasons from 2019 to 2023 was mainly characterized by Class IV.The change of water quality index concentration in a year demonstrated a certain periodicity, and the water pollution degree in the flood season was increased year-on-year.Total phosphorus was the main over-standard factor of water quality.The total phosphorus in the lake was mainly composed of dissolved inorganic phosphorus.From the perspective of spatial distribution, the water quality of East Lake was better than that of West Lake and Middle Lake.The water quality of non-restoration aquaculture area and aquatic vegetation restoration area was better than that of enclosure aquaculture area.The pollutant concentration at the estuary point had a significant impact on the water quality of Yangcheng Lake.The contents of permanganate index, total phosphorus, total nitrogen and other indicators at the estuary point were significantly higher than those in the lake area, which was the key factor affecting the water quality of the Lake.The results showed that the phosphorus content in sediments of the purse seine culture area was higher.During flood seasons, the increase in temperature resulted a decrease in the dissolved oxygen of water, and consequently a high risk of release of the total phosphorus from the sediments.In addition, aquatic vegetation planting may have a strong correlation with transparency improvement, permanganate index reduction and chlorophyll a reduction.The reduction of phosphorus by aquatic vegetation may be mainly related to the content of total dissolved phosphorus.

Hubei Province is located in the middle reaches of the Yangtze River, which possesses many lakes.In recent years, some lakes faced increasingly ecological environment problems, such as water quality decline and aquatic ecosystem degradation.In this study, the four largest lakes (Honghu, Liangzi Lake, Futou Lake, and Changhu) were selected for investigation.The results showed that the water quality of all four lakes showed different degrees of deterioration from 2016 to 2023.Among them, the water quality of Honghu Lake experienced the most significant deterioration, and the classification of surface water environmental quality standard dropped from Class III in 2016 to Class V.The total phosphorus and permanganate index were the main parameters that exceeded the standards.The survey conducted in the spring and summer in 2023 showed that Honghu Lake was in a moderate eutrophication state.Changhu Lake was in a mild eutrophication state, and Liangzi Lake and Futou Lake were in a moderate to mild eutrophication state.The biodiversity of phytoplankton, zooplankton, and benthic animals in the four lakes was at a relatively low level.This assessment showed that the water ecological environment quality of Honghu Lake was poor, Liangzi Lake and Futou Lake were in average level, and Changhu Lake was poor in spring and in average in summer.

The construction of ecological civilization and low-carbon transformation in the Yangtze River Economic Belt (YREB) are the key tasks of high-quality economic development in China. Based on the data of carbon emission intensity of 1 069 counties in the YREB from 2005 to 2019, the development trend and spatial characteristics of carbon emission intensity were investigated using statistical methods of nuclear density estimation, Dagum Gini coefficient, standard deviation ellipse and exploratory spatial data analysis. The results showed that: (1) The carbon emission intensity of the counties under the jurisdiction of the YREB generally showed a steady downward trend. The  dispersion degree and absolute difference had also decreased, and the absolute difference had narrowed. The carbon emission intensity of the YREB as a whole and the counties under the jurisdiction of the upper, middle and lower reaches demonstrated multipolar polarization, but tended to weaken. (2) The overall difference of carbon emission intensity in counties under the jurisdiction of the YREB showed a downward trend, and the degree of regional imbalance was generally at a high level. The main contribution source of the overall difference is the hypervariable density, with an average contribution rate of nearly 40%, followed by the intra-regional difference, with an average contribution rate of about 33%, and finally the inter-regional difference. (3) The regional distribution of carbon emission intensity at county levels showed a spatial pattern of northeast-southwest trend, and its distribution center of gravity showed a trend of first towards southwest and then turning back to northwest. The mode of local spatial agglomeration was mainly "low-low" agglomeration, with more districts and counties mainly distributed in eastern Sichuan and southwestern Chongqing in the upper reaches of the YREB, majority of Hunan and Jiangxi in the middle reaches and majority of Hubei. Based on this, efforts should be made to promote emission and carbon reduction according to local conditions and urban policies. This aims to enhance the spatial linkage and coordination between districts and counties, and to optimize the government assessment and supervision and accountability mechanism to jointly help the high-quality development of the YREB.

The achievement of harmonious advancement in high-standard ecological conservation and high-quality economic development within the Yangtze River Economic Belt (YREB) is of paramount significance for the comprehensive construction of a modern socialist strong country in China. This study concentrated on the 11 provinces and cities within China’s Yangtze River Economic Belt. A comprehensive index evaluation system was constructed. By employing the coupling coordination measurement model, grey relational model, and Panel Vector Autoregression (PVAR) model, this study measured and analyzed the coupling coordination degree and interactive relationship between the ecological environment and high-quality economic development of the Yangtze River Economic Belt from 2012 to 2022. The results indicated that: (1) the coordinated development level between the ecological environment and high-quality economic development in the YREB had undergone a phased evolution from "moderate maladjustment-basic coordination-moderate coordination," exhibiting an overall spatial differentiation pattern of "lower reaches of the Yangtze River > middle reaches of the Yangtze River > upper reaches of the Yangtze River." (1) By the year 2022, only Shanghai, Zhejiang, and Jiangsu had achieved a moderate coordination, while the remaining provinces and cities were all in a state of basic coordination. (3) The correlation between regional subsystems within the YREB and the coupling coordination degree of the two systems showed a relatively balanced degree of association, with the correlation degree of each subsystem indicator generally exceeding 0.8, indicating a robust interactive relationship. (4) In the early development stage of the YREB, the ecological environment was significantly impacted, but subsequently recovered and stabilized over time. The short-term negative impact of the economy on the ecological environment gradually diminished. Accordingly, it was essential to implement measures such as targeted policies, environmental regulation improvements, and enhanced intra-regional cooperation to further promote the coordinated development of the ecological environment and economy in the YREB, to achieve the sustainability of regional development.

Comparing the characteristics of industrial spatial organization of mature and growing metropolitan areas and identifying their formation mechanisms can help summarize the universal laws of industrial spatial organization in metropolitan areas, and provide a basis for optimizing industrial spatial organization in growing metropolitan areas. Taking the Shanghai metropolitan area and the Wuhan metropolitan area as examples, this study adopted the logic of comparative study to identify the common patterns and differences of industrial spatial organization in spatial agglomeration, functional collaboration and formation mechanisms of the two metropolitan areas. The results showed that in terms of spatial agglomeration characteristics, the Shanghai metropolitan area presented a gradient configuration of industrial chain division pattern; The Wuhan metropolitan area presented a near-regional organization, with a strong manufacturing links, a weak R&D and service link, and links in the industry chain were synergistically clustered in the near-region circle; It was found that a distance of 10 km was the key distance node for the combination of production and innovation factors of the two metropolitan areas, but the outer circle of Wuhan metropolitan area lacked the support of innovation factors. In terms of functional collaboration characteristics, the Shanghai metropolitan area were much stronger than the Wuhan metropolitan area in terms of network capacity, density and cooperation efficiency. The Shanghai metropolitan area was a polycentric network with both neighboring organizations and leapfrog organizations t, while the Wuhan metropolitan area was a single-center network with neighboring organizations; The near-circle organization of supply chain was a common feature of the two metropolitan areas, but the supplier self-sufficiency rate of the Wuhan metropolitan area was low. Finally, based on the comparative results and mechanism analysis of the characteristics of industrial spatial organization, this study put forward corresponding suggestions for the optimization organization of industrial space in growing metropolitan area from the perspective of core strengthening, functional collaboration innovation-driven and strengthening the sub-nucleus.

To grasp the spatial-temporal distribution characteristics of fish resources in the Jianli and Hukou reaches of the middle Yangtze River, a synchronous fishery resources survey was conducted in June (wet season) and November (dry season) of 2023 using a combination of acoustic and fish catch methods. The results indicated that in terms of temporal distribution, the fish densities in the Jianli reach during the two periods were 47.66 and 25.27 individuals per 1 000m3, with average target strengths of -59.04 and -62.24 dB, respectively. Meanwhile, the fish densities in Hukou section were 43.50 and 23.08 individuals per 1 000 m3, with average target strengths of -55.01 and -59.28 dB, respectively. Significant differences (**P<0.01) were observed in fish density and target strength between the two periods in both Jianli and Hukou sections. In terms of spatial distribution, the fish density was unevenly distributed. The Jianli section demonstrated a higher concentration in the areas with winding river channels, while the Hukou section had a higher concentration in areas with dense sandbars. Both Jianli and Hukou sections exhibited the highest fish density in the bottom layer, followed by the middle layer, and the lowest in the surface layer during the high-water period. In contrast, during the dry season, the highest fish density was observed in the middle layer, followed by the bottom layer, and the lowest in the surface layer. However, differences in fish density and target strength among these layers during the dry and flood seasons were not statistically significant (P>0.05).Combined with the fishing catch survey data, it was found that the fish composition in both Jianli and Hukou sections was dominated by Cyprinidae, with a majority of small-sized fish species distributed mainly in the middle and lower water layers. The temporal and spatial distribution characteristics of fish in Jianli and Hukou sections were closely related to their ecological habits, such as reproduction, feeding, and overwintering behaviors. These findings provided data support for assessing the restoration and protection of fish resources in the middle Yangtze River after the implementation of the fishing ban policy.

Under the concept of green and low-carbon development, it is of great significance to explore the spatial-temporal characteristics and the influencing factors of the efficiency of “cutting carbon, reducing pollution, expanding green” for urban land. Based on a panel dataset covering 108 cities from 2003 to 2021 in the Yangtze River Economic Belt, the undesirable output super-efficiency SBM model, kernel density estimation, spatial autocorrelation analysis, and spatial panel econometric models were used in this study. Findings found that: (1) The efficiency values showed an overall upward trend, with values rising from 0.338 in 2003 to 0.677 in 2021. These valuesshowed stage-specific characteristics in regional disparities and widening intercity differences, along with polarization phenomena. (2) Positive spatial autocorrelation was evident at the global level, whereas at the local scale, four types of agglomeration patterns were identified, i.e. high-high, low-low, low-high, and high-low. (3) A significant positive spatial spillover effect was confirmed, where a 1% increase in efficiency of “cutting carbon, reducing pollution, expanding green” induced a 0.155% rise in neighboring cities. (4) Spatial effect decomposition disclosed varying direct and indirect effects of influencing factors on the efficiency. Therefore, it was necessary to consider the spatial correlations and spillover effects among cities to enhance the efficiency of urban land changes in the Yangtze River Economic Belt.

Based on the land use data of the Yangtze River Delta (YRD) urban agglomeration in 2000, 2010, and 2020, this article analyzed the growth and decline of the " Production-Living-Ecological" (PLE) space in the past 20 years.Using 2020 as the benchmark, a patch generated land use change simulation (PLUS) model was used to simulate and analyze the different evolutionary characteristics and ecological environmental effects of the "PLE" space in the region in 2030 under three scenarios: natural development, economic priority, and ecological protection.The results showed that: (1) From 2000 to 2020, the production space of the YRD urban agglomeration would continue to shrink.The living space would continue to expand, and the ecological space would first increase and then decrease.(2) From 2000 to 2020, the ecological environment quality index would continue to decrease from 0.4837 to 0.4765, and the low-quality areas would continue to expand.The continuous reduction of agricultural production land and the occupation of forest and water ecological land were the main factors leading to the decline in ecological environment quality.(3) The living space would expand and the production space would shrink in all the three scenarios.The production land would decrease the least in the ecological protection scenario.(4) Under the ecological protection scenario, the ecological environment quality index of the study area was the highest, and the ecological environment quality level showed a trend of continuous improvement.It was suggested that strengthening the protection of cultivated land and forest land, rational planning and layout, and improving urban green space would promote the sustainable development of social economy under the ecological protection scenario.

The study on the changing trends and driving factors of the Normalized Difference Vegetation Index (NDVI), an important indicator to reflect vegetation growth, is of great significance for maintaining regional ecological security. Taking Danjiangkou Reservoir area as the research object, this paper constructed a 1 km resolution NDVI series from 1982 to 2022, by using GIMMS NDVI and MODIS NDVI data based on pixel-level linear regression analysis. These data were used further to analyze the temporal and spatial characteristics of NDVI in the study area. The spatial heterogeneity of vegetation and the driving factors were explored using the geographical detector. The results showed that: (1) The annual mean NDVI increased at a rate of 0.002 6 per year. The spatial distribution of NDVI was characterized by higher values in the northwest and lower ones in the southeast. The areas of low-value were concentrated in low-altitude areas such as Hanzhong, Ankang and Shiyan. (2) NDVI within the reservoir area generally showed an improvement, but with a local degradation. The area with a significant improvement accounted for 98.23% of the total area, which was widely distributed in the whole research area. The degraded area accounted for less than 1%. (3) Annual potential evapotranspiration, elevation and geomorphology were the dominant factor influencing the spatial distribution of local vegetation. The interaction between sunshine hours and elevation had the greatest influence on the spatial distribution of NDVI. The interactions between the influencing factors showed either a two-factor enhancement or nonlinear enhancement.

In the context of rapid urbanisation, building an urban-rural ecological security pattern is an important way for China to narrow the gap between urban and rural ecological security levels and to promote integrated urban-rural ecological development.The urban-rural ecological differences lead to the slow process of urban-rural ecological integration development.Taking Wuhan city as an example and urban-rural ecological integration as an orientation, this paper analyzed the current level of urban-rural ecological integration and its influencing factors.A comprehensive ecological resistance surface based on the measurement of the comprehensive impact degree of ecological integration was constructed.The ecological sources at meso-scale and theimportant ecological corridors based on the least cumulative resistance and gravity model were identified.The corridors were optimized by using a hydrological analysis model, and an overall urban-rural ecological safety pattern in Wuhan was constructed.This study showed that: (1) There was obvious spatial differentiation in the level of urban-rural ecological integration in Wuhan, and urban-rural ecology was in an unbalanced state of development; (2) The main driving force for the development of urban-rural ecological integration was the ecological environment and anthropogenic activity factors, with less socio-economic impacts; (3) A ‘three horizontal and two vertical’ network of ecological security patterns were constructed, which included 51 urban and rural ecological sources, 115 important ecological corridors, 220 radial corridors and 129 ecological nodes; (4) The ecological resistance surface corrected by the urban-rural ecological integration influence index was more in line with the urban-rural reality, and the ecological security pattern demonstrated the effect of promoting the development of urban-rural ecological integration.The ecological security pattern of urban and rural areas in Wuhan was constructed to provide a more microscopic theoretical reference for the optimization of ecological space in urban and rural areas, as well as to provide a scientific reference for the promotion of ecological integration between urban and rural areas, for the safeguarding of ecological security in urban and rural areas, and for the promotion of sustainable development in the region.

The increasingly frequent seasonal droughts in the Poyang Lake Basin have caused a series of ecological and environmental problems. One solution is to timely improve the humid conditions in the lake area through water level regulation measures. In order to determine the impact of regulation on the net water consumption of wetlands, this paper firstly defined the regulation scheme using three parameters: ‘regulation water level- start time- duration’ based on different wetting objectives. Then, the entire lake area was divided into different wet zones according to the water surface and different groundwater depths, and the corresponding wetland area and net water consumption changes were calculated for different zones. The regulation schemes included three controlled water levels (13, 11, and 15 m) for different humid years (average, dry, humid), three start times (from the 1st, 280 th, and 320 th day of each year), and three duration times (90, 40, and 40 days). The results showed that, compared with the unregulated background situation, net water consumption increments of wetlands in average, dry, and humid years under different schemes were 1.48-4.12, 1.49-3.04, and 1.46-3.15 ×108 m3, respectively. Although the water consumption increment was very low (0.10%-0.27%, 0.10%-0.20%, and 0.10%-0.21%) compared with the total wetland inflow (150 billion m3), they were significant compared to the current net inflow consumption of the wetland (2 billion m3), which was in the range of 7.42%-20.59%, 7.42%-15.17%, and 7.30%-15.73%. This study indicated that considering the changes in net water consumption was essential in proposing the proper ecological water level of Poyang Lake. Outcomes of this study provide technical support for a more rational water resource allocation.

The achievement of green total factor productivity (TFP) growth is an important way for the Yangtze River Economic Belt (YREB) to practice green and low-carbon development and achieve high-quality development. This study took the measured green TFP of the YREB from 2005 to 2020 as the research object, and used the methods of spatial distribution map and standard deviation ellipse to explore the temporal and spatial evolution and agglomeration characteristics from the perspective of urban agglomeration. The driving factors of the spatial differentiation of green TFP were studied by means of geodetector. The results showed that: (1) From 2005 to 2020, the green TFP of the whole YREB, the middle reaches of the Yangtze River city cluster and the Chengdu-Chongqing city cluster showed a development trend of a first decline and then an increase. The Yangtze River Delta city cluster showed a development trend of a first growth and then a decline and then an increase. (2) The green TFP of the YREB showed a spatial pattern of "Yangtze River Delta urban Agglomeration > Chengdu-chongqing urban Agglomeration > Urban agglomeration in the middle reaches of the Yangtze River "and" Central City > Non-central city; (3) The green TFP of the Yangtze River Delta urban agglomerations and the middle reaches of the Yangtze River experienced an evolutionary process of "first decentralization, then agglomeration". The agglomeration development characteristics of the green TFP of the Chengdu-Chongqing urban agglomerations were not obvious, but there was an obvious trend of migration to the east, and the central cities had a greater impact on the distribution pattern of green TFP. (4) The single factor detection results showed that urban development level, technological innovation and environmental regulation level were the core driving factors of the spatial differentiation of green TFP. The interactive detection results showed that the interaction of driving factors was greater than that of single factors, and the interaction of digitalization level and environmental regulation level in 2020 had the strongest interpretation of green TFP.

The measurement of high-quality economic development level in the Yangtze River Economic Belt, along with an examination of its distribution dynamics, transfer characteristics, regional disparities, spatial agglomeration and obstacle factors, holds significant practical implications for establishing exemplary models of regional economic development and constructing a pilot demonstration zone for high-quality economic development in China. Based on fundamental data from 102 cities in the Yangtze River Economic Belt spanning from 2011 to 2020, this study constructs an evaluation index system for high-quality economic development. The level of high-quality economic development is measured through a comprehensive utilization of vertical and horizontal scatter degree method, fixed base efficiency coefficient method, and linear weighting method. Building upon this foundation, systematic analysis is conducted employing kernel density estimation, Markov chain estimation, Dagum Gini coefficient, Arcgis mapping technique, spatial Moran’s index, Moran scatter plot as well as obstacle factor diagnosis. The findings are as follows: (1) The level of high-quality economic development in the Yangtze River Economic Belt has steadily improved during the study period, with significant variations observed among provinces and cities. The regional development gap underwent an initial expansion followed by a subsequent narrowing, leading to a transformation from a pattern of multi-level differentiated gradient development to one of polarization, while also witnessing the emergence of a trend towards balanced development. (2)There is a high probability that each city will maintain its current level of development, confirming the phenomenon of solidification at high-level cities. (3)The regional gap primarily stems from inter-regional disparities and has shown a decreasing trend over the years. (4)High-quality development exhibits both high agglomeration and low agglomeration spatial characteristics, with significant radiation effects from higher-level cities. (5)The per capita utilization of foreign capital, residents' living standards, the level of marketization, and the rationalization of industrial structure are key determinants influencing the high-quality economic development in the Yangtze River Economic Belt. Additionally, factors such as unemployment rate, per capita participation in pension insurance, and energy efficiency also pose significant challenges to enhancing the level of high-quality economic development in certain provinces and cities.

While China is entering a new stage of development, the green value of digital intelligence is increasingly prominent. Improving green total factor productivity is an inevitable requirement for accelerating the development of new quality productivity and promoting high-quality economic development. Taking 105 prefecture-level cities in the Yangtze River Economic Belt from 2011 to 2019 as samples, the SBM-GML index, fixed effect model and moderating effect model were used to empirically test the influence of digital intelligence on green total factor productivity. This study found that: (1) Digital Intelligence contributed significantly to green total factor productivity, mainly through green technological advances. (2) Science and technology innovation played a positive moderating role in digital intelligence to drive green total factor productivity. (3) The promotion effect of digital intelligence on green total factor productivity was significant in the upper, middle and lower reaches of the Yangtze River Economic Belt The promotion effect was ranked as “upstream, downstream, and middle reaches” at the regional level, and “resource-based cities, non-resource-based cities” at the resource endowment level. (4) The moderating effect of science and technology innovation was significant in the upstream and downstream of the Yangtze River Economic Belt, as well as in large cities of type I and above and non-resource cities. Policy recommendations were put forward to improve the new quality productivity of the Yangtze River Economic Belt, in terms of building a digital intelligent China, promoting scientific and technological innovation, and fostering greening.

The frequent occurrence of pollution disputes between inter provincial river basins reflects the long-standing game problem of "competition over cooperation" among local governments in river basin governance, and reflects the importance and urgency of strengthening collaborative governance to promote ecological environment protection in river basins. For this reason, China has implemented a major policy reform - Inter Provincial Watershed Ecological Compensation. Therefore, it is urgent to answer how the Inter Provincial Watershed Ecological Compensation achieves collaborative governance of watersheds and its policy effects. Inter Provincial Watershed Ecological Compensation was taken as a quasi experiment, and the logical approach to achieving coordinated watershed governance was explored. Based on balanced panel data from 30 provincial-level administrative regions in China from 2007 to 2020, the effect of inter provincial watershed ecological compensation were empirically examined using a multi period double difference method. The research results indicate that: (1) Inter Provincial Watershed Ecological Compensation can effectively balance the cost-benefit issues of different local governments in basin governance in the upstream, downstream, left and right banks, and are an effective strategic institutional arrangement for achieving coordinated basin governance. (2) The implementation of inter provincial watershed ecological compensation can significantly improve the resilience level of water ecology in the basin, and has become a new path for achieving mutual benefit and win-win in current basin collaborative governance. Based on research findings, corresponding policy recommendations are proposed from three aspects: constructing a comprehensive ecological compensation mechanism for the entire watershed in China, improving a market-oriented and diversified compensation system for the watershed, and improving the construction of a legal system for ecological compensation in the watershed.

Rapid expansion of urbanization has led to the formation of urban heat islands, which further exacerbates ecological and environmental problems. Clarifying the variation characteristics of urban surface temperature and exploring their main driving factors are critical for regulating urban thermal environments. Based on the MOD11A2 and MYD11A2 surface temperature products, this paper analyzed the spatial-temporal evolution and the driving factors of the local surface temperature on Hefei metropolitan area from 2003 to 2022. The statistics, trend analysis and geospatial correlation modeling, combined with the Geo-detector model were used. The results showed that: (1) The annual average LST in the study area fluctuated upward from 2003 to 2022 (0.08 °C/year), with daytime warming rates (0.11 °C/year) significantly higher than those at night (0.06 °C/year). (2) The significant warming areas during all-day were mainly distributed in the central-northern and southeastern parts of the area. The daytime zone of significant warming spread outward from the all-day zone, but most of the region showed insignificant warming during the night. (3) Over the past 20 years, the area of the cold-hot spots region changed dramatically. The LST hot spots spread to the northeast while the LST cold spot area clustered to the southwest corner during the day. The LST hot spots clustered to the south while the LST cold spot area spread to the center during the night. (4) The potential evapotranspiration, air temperature, and vegetation index were the major factors affecting the daytime LST in the study area, with air temperature and land use type being the dominant factors causing changes in surface temperature over the years. At night, the vegetation index, precipitation, and air temperature were the major driving factors affecting the nighttime LST, and the interpretability of LST had been significantly enhanced by the nighttime light index. This study provided a scientific basis for the coordinated development of urban ecological protection.

The evaluation of water resources utilization in the source area before and after the operation of the inter-basin water transfer project is of great significance for optimizing water resource allocation, promoting the coordinated development of water resources and economy, and improving the sustainable level of water resources. The water footprint of the water source area of the middle route of the South-to-North Water Diversion project from 2005 to 2019 was calculated in this paper. The evaluation index system incorporating regional water resources sustainability, ecological security, economic coordination and social coordination was constructed to evaluate and analyze the overall water consumption and water resource utilization status of the water source area. The results showed that: （1） By 2019, the overall total water footprint of the water source area had decreased to 7.316 billion m3, while the green water footprint had accounted for a relatively high proportion. The blue water footprint grew by 52.48% between 2005 and 2019. The grey water footprint showed a fluctuation during 2005-2013, but a significant decrease trend from 2014 to 2019; （2） The overall water resources ecological security level and the coordination level between water resources and society in the water source area were relatively good. The unsustainable state of resources was more severe. The coordination between water resources and economy was gradually weakened. This study provided comprehensive theoretical and data support for the formulation of decision-making plans and management methods for sustainable utilization of water resources in the source area of the middle route of the South-to-North Water Diversion Project. Analysis and assessment of water resources use and water footprint were conducive to obtaining efficient methods of water resources utilization, enhancing water resources protection, and providing reliable basis for effective allocation of water resources.

Waves are one of the primary external forces causing soil erosion in the riparian zone of the Three Gorges Reservoir. Studying the characteristics of nearshore wave forces is crucial for understanding soil erosion processes in this area. However, the spatial and temporal variations of nearshore wave forces in the Three Gorges Reservoir remain unclear. This paper employed in-situ observation methods and relevant recommended formulas to quantitatively calculate and analyze the spatiotemporal variations of nearshore wave forces in the Three Gorges Reservoir, main and tributary streams. The results indicated that: (1) Nearshore wave forces in the Three Gorges Reservoir exhibited significant spatial and temporal heterogeneity (P<0.01), with values ranging from 0.02 to 12.14 kPa, showing a reservoir impounding cycle. The frequency distribution of nearshore wave forces could be fitted using the Lorentz distribution curve. (2) Nearshore wave forces increased with rising water levels. At a water level of 175 m, the average nearshore wave force was 1.7 times and 1.2 times that at 150 m and 165 m water levels, respectively. At 150 m water level, nearshore wave forces primarily ranged from 0 to 1.5 kPa, with a cumulative frequency of 91.4%. (3) There were significant differences (P<0.01) in nearshore wave forces between the main and tributary streams. The average nearshore wave force in the mainstream was three times that of the tributaries. (4) The variation in nearshore wave forces across different reservoir sections was irregular. However, at the same water level, the average nearshore wave forces in the Zigu, Badong mainstreams, which were closer to the Three Gorges Dam, were significantly higher than those in the Zhongxian mainstream, that was farther away from the dam. (5) The peak values of nearshore wave forces during typical days coincided with shipping activities, indicating that the intensity of shipping activities was a key factor causing significant differences in nearshore wave forces between the main and tributary streams. These research findings provided scientific references for studying the hydrodynamic characteristics of nearshore areas and the soil erosion environment in the riparian zone of the Three Gorges Reservoir.

A systematic analysis of the spatiotemporal evolution characteristics of carbon emissions in urban agglomerations in the middle reaches of the Yangtze River is of great significance for promoting the coordinated peak of carbon emissions and achieving green integrated development. This article used the coefficient method to calculate carbon emissions, and further explored the spatiotemporal evolution characteristics and influencing factors of carbon emissions in urban agglomerations in the middle reaches of the Yangtze River from 2005 to 2020. The results showed that: （1） The overall carbon emissions showed a fluctuating growth trend, but the carbon emission intensity showed a decreasing marginal trend. （2） Carbon emissions exhibited a clear positive agglomeration layout of high-high and low-low modes. （3） Carbon emissions exhibited absolute club convergence with velocity heterogeneity, rather than σ- convergence and absolute β-convergence. （4） The scale of fiscal expenditure was the most important factor driving the growth of carbon emissions in the study area, followed by the level of economic development and urbanization. Energy structure and intensity certainly suppressed the growth of carbon emissions and were the main driving factors for promoting carbon reduction.

As a strategic emerging industry, digital industry is an important driving force to promote the high-quality development of the Yangtze River Economic Belt (YREB) and construct a new advantage in regional competition. Exploring the evolution of the spatio-temporal pattern and driving factors of digital industry in the YREB is of great practical significance for optimizing the layout of digital industry. Based on the data of more than 300 000 digital enterprises from 2000 to 2020, this study used the descriptive statistics, standard deviational ellipse and multi-scale geographically weighted regression modelling methods to conduct a research. The results showed that: (1) The number of digital enterprises increased significantly during. The spatial distribution of the digital industry showed that “the core of the downstream cities was prominent, and the middle and upper reaches of the cities were gradually expanding”. （2）In terms of sub-industry, the digital product production industry showed a trend of “prominent downstream agglomeration core, and gradual expansion of the middle and upper reaches with the provincial capital city as the core”. The digital product service industry showed the characteristics of “close connection between the middle and lower reaches of the city, and continuous agglomeration in the lower reaches”. The digital factor support and technology emerging industry showed a trend of “the provincial capital city being the core, and a multi-core piecewise distribution”.（3）The spatial distribution of digital industries was generally affected by a variety of factors such as location, market, technology and institutions. The role of each driver was spatially heterogeneous. In addition, there existed differences in the impact of different types of digital industry drivers, i.e. digital production enterprises focused more on location factors and were path-dependent. The digital product service industries relied mainly on consumers and markets and were more path-creative. The digital support and technology emerging industries were found to be both path-dependent and path-creative in the location selection.

Small wetlands are distributed widely. However, the soil carbon stock and ecological stoichiometric characteristics of the wetlands have received little attention, which may restrict the accurate calculation of the budget of wetland carbon stock. In this study, six types of wetlands in the Tangma Reservoir watershed in southern Jiangsu Province were selected, which included river, water-level-fluctuating zone of reservoir, open-water zone of reservoir, freshwater farm, agricultural pond, and paddy field. Specifically, soil profiles of 1 m depth were collected and analyzed for soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), and the ecological stoichiometric ratio. Soil SOC, C/N, C/P and N/P were measured as 3.65±3.60~8.17±6.26 mg/g, 7.7±4.6~10.8±2.5, 18.0±6.2~34.4±16.4 and 1.9±0.5~3.1±1.4, respectively. Significant differences of soil SOC, TN, TP, C/N, C/P, and N/P among different wetlands were identified (p < 0.01). These elements were generally higher in the water-level-fluctuating zone of reservoir and paddy field, and lower in the open-water zone of reservoir, river, and freshwater farm. The soil carbon density of the six types of wetlands ranged 4.41±3.94~9.37±5.81 kg/m2, which was lower than the average of national wetlands, but at a close level to the results of coastal wetlands and eastern lake wetlands in China. The relatively higher TN and TP indicated that the wetlands had a great potential for carbon sinks.

Building an environmental collaborative governance system involving multiple subjects is a significant measure to promote Chinese-style modernization. This paper constructed a dynamic evolutionary game model of "government-enterprise-public", based on perspective of prospect theory. This study analyzed the strategy selection and decision-making mechanisms of multi-subjects in environmental governance. Through numerical simulation experiments using MATLAB software, this paper revealed how factors such as the initial intentions of the players, the intensity of rewards and punishments, risk preference coefficients, and loss aversion coefficients affected the effectiveness of environmental collaborative governance. These findings indicated that:（1）The decision-making behavior of game players was influenced by their own and others' strategy selection and reached an equilibrium state under certain conditions.（2）Although the initial intentions of game players and the strength of governmental rewards and punishments affected the speed of system evolution, these factors did not change the final strategy selection, and the system evolved stably towards an ideal state.（3）The coefficients of risk preference and loss aversion in the perceived utility function significantly affected stable strategies in system evolution, which enhanced game players' perception of the value of rewards. Punishments were crucial for achieving optimal equilibrium.

Understanding the spatial distribution characteristics and its influencing factors of cropland topsoil available potassium contents is essential for field nutrient management and soil resource conservation.Based on 4409 surface (0~20 cm) soil sample points collected during 2017-2019, the spatial distribution pattern and the influencing factors were analyzed in this study, using geostatistical methods, correlation analysis, analysis of variance and random forest model.The results showed that the available potassium contents in the study area ranged from 10.00 to 373.00 mg/kg, with a mean value of 110.48 mg/kg, which was lower than that of the national average (139 mg/kg); The coefficient of variation was 50.12%, which indicated a moderate spatial variability.The results of the semi-analysis of variance (ANOVA) showed that the best theoretical model was the exponential model.The model indicated a coefficient of determination of 0.975, the nugget effect of 62.9%, and the variability range of 23.5 km, which implied that the spatial distribution was determined by both structural factors and stochastic factors.The interpolation results showed that the cropland topsoil available potassium contents in the Sichuan Basin demonstrated a patchy spatial distribution pattern.Random forest model analysis showed that soil texture and pH were the most important factors affecting the cropland topsoil available potassium contents in the study area, followed by temperature and rainfall, while the effects of straw return, potash fertilizer application, topographic factors and soil type were relatively weak.The above results indicated that soil properties were the primary controlling factors for the spatial distribution of cropland topsoil available potassium contents.Under cultivation conditions, regulating soil texture and soil pH was the key to increase the cropland topsoil available potassium content.The formation of measurements such as straw return and fertilizer application should fully consider the effects of climate, topography and soil type.

Under global warming, the Yangtze River Basin has experienced significant warming and an increased frequency of extreme precipitation events. This study systematically evaluated the performance of climate models and quantified the evolution of extreme precipitation under various warming levels (1.5°C, 2°C, 3°C, and 4°C) using the NEX-GDDP-CMIP6 (N-CMIP6) dataset and a multi-model ensemble (MME). The results showed that, from 1961 to 2023, annual precipitation (PRCPTOT) and extreme precipitation intensity indices (R95p, Rx1day, Rx5day) exhibited no statistically significant long-term trends but demonstrated substantial spatial divergence (p>0.05). Specifically, short-duration heavy precipitation increased in the lower basin, while it attenuated in the middle basin. Concurrently, consecutive dry days (CDD) significantly decreased at a rate of -0.89 days per decade (p<0.05). As warming intensified, extreme precipitation amplified nonlinearly. The growth rates in the 3°C-4°C phase exceeded those by 3-6 times in the 1.5°C-2°C phase. At 4°C of warming, the increase in short-duration precipitation (Rx1day, 23.3%) was 1.5 times higher than that of prolonged events (Rx5day, 15.7%), and precipitation concentration in parts of the middle-lower basin exceeded 50%. The spatial divergence of hydroclimatic risks intensified: the upper and middle regions faced concurrent heavy precipitation and shortened drought duration, while the lower basin was exposed to compounded risks of amplified extreme precipitation and prolonged droughts. Limiting global warming to 1.5°C-2°C could reduce extreme precipitation amplification by 46%-84%, and might significantly mitigate associated risks. These findings provided a scientific foundation for water resource management and climate adaptation strategies in the Yangtze River Basin, and highlighted the critical importance of controlling global temperature rise for sustainable regional development.

To understand the overall status of early stage fish resources in the Songzi River in the middle reaches of the Yangtze River and to explore the impact of hydrological processes on these resources, a survey of early stage fish resources was conducted from May to July 2022 in the Songzi River section. The results showed that fish populations concentrated their spawning activity by the end of June, with a decrease in egg numbers in July and a significant increase in fry numbers. Cross-analysis of the impact of hydrological processes on fish spawning revealed that changes in egg numbers preceded changes in flow by 0 to 2 days; fry numbers, on the other hand, showed a significant lagged correlation with flow (3 to 7 days). During the survey period, changes in egg numbers exhibited no significant lagged correlation with water temperature, whereas fry numbers displayed a significant lagged correlation with temperature. Using Granger causality analysis to investigate the causal relationship between hydrological processes and fish spawning, it was found that flow and water temperature had no significant causal relationship with changes in egg numbers, but did show a significant causal relationship with changes in fry numbers. Specifically, flow levels at 3 to 7 days prior had a stronger correlation with changes in fry numbers, and water temperature at 2 days prior exhibited a significant causal relationship with fry numbers. Further analysis, considering the concurrent operation of the Three Gorges Reservoir (TGR) in the upper Yangtze River, indicated that the ecological regulation of the TGR was an important factor affecting changes in early stage fish resources in the Songzi River. This regulation not only supported fish spawning in the Yangtze River, but also played a positive role in supplementing fish resources in Dongting Lake connected to the Songzi River.

To understand the fish community structure and its variation in the Four Major Chinese Carps Aquatic Germplasm Resources Reserve in Chongqing section of the upper reaches of the Yangtze River (after this referred to as the protected area) at the beginning of the "Ten-Year Fishing Ban",this study investigated the fishery resources and collection of environmental factors in the protected area from May to June and from October to November 2023. A total of 56 fish species were collected,which belonged to 6 orders,16 families,and 43 genera. Among the species,9 were endemic to the upper reaches of the Yangtze River (16.07%).In addition,there were 8 alien fish species (14.29%). The community composition was mainly composed of bottom fish,quiet and slow-flowing fish,sink-laying fish,and omnivorous fish. The small fish such as Pseudobrama simoni,Hemifilter leucisculus,and Squalidus argentatus was the dominant species in the protected area. The Shannon-Wiener index,Margalef index,Pielou index,and Simpson index ranged from 1.49 to 2.80,4.14 to 5.69,0.43 to 0.79,and 0.53 to 0.90,respectively. The species diversity index was significantly correlated with permanganate index,flow velocity,transparency,and substrate type (P<0.05). Cluster analysis and non-metric multidimensional scaling analysis (NMDS) showed that the fish community types in the river section of the protected area were divided into three groups,i.e.,group one: Luoqi and Mudong,group two: Xiamenkou,Linshi,and Wujianghekou,group three: Zhenxi. Redundancy analysis (RDA) showed that flow velocity and water depth were the key environmental factors that significantly affected the spatiotemporal distribution of fish communities in the protected area (P<0.01). The abundance biomass comparison curve (ABC curve) analysis showed that the fish community structure in the Xiamenkou section was relatively stable,while in other sections was moderately to severely disturbed. Compared with the historical data,the fish community in the protected area had undergone significant changes. This study systematically analyzed the characteristics of fish community structure,spatio-temporal changes and the relationship with environmental factors in the protected area. This study supplemented the existing data on the current status of fish resources and provided a scientific basis for fishery resources management and initial ecological assessment of the "Ten-Year Fishing Ban" in the study area. 

Eco-environmental protection in China will enter the key stage of coordinated management of pollution and carbon reduction. The in-depth integration and development of digital and intelligent technologies (DIT) will provide new major opportunities and technical support for coordinated management of pollution and carbon reduction (PCR). In this paper, an index system was constructed for the development level of DIT integration and the level of coordinated governance for PCR. The entropy weight method was used for hierarchical assignment and calculation. The panel data of 27 cities in Yangtze River Delta region of China from 2011 to 2022 were adopted as the research object. A spatial-temporal analysis of the development level of DIT integration and the level of coordinated governance for PCR was conducted. The bidirectional fixed effects model and the mediation effect model were employed to study the influence and mechanism of the development of DIT integration on the coordinated governance of PCR. The results showed that: (1) the level of numerical intelligence integration development (NID) and the level of collaborative governance for PCR in the Yangtze River Delta (YRD) region significantly increased from 2011 to 2022, accompanied by the occurrence of spatial diffusion phenomena; (2) NID significantly contributed to the improvement of collaborative governance for PCR in the YRD region; (3) The integration of DIT development could promote the coordinated management of PCR in the YRD region by improving the technological innovation capability and optimizing the energy production structure.

The flow and allocation efficiency of elements in urban-rural integration are the key factors affecting carbon emission performance.There is a need to systematically reveal the impact of urban-rural integration on carbon emission performance, which can provide support for building a beautiful China.Based on China's inter-provincial panel data from 2001 to 2021, the two-way fixed effects model, mediation effect model and spatial Durbin model were applied in this study.The results showed that: (1) China's urban-rural integration was dominated by medium-low and low-level zones, and the spatial differences were  expanding and then gradually narrowing; the regional differences in China's carbon emission performance were narrowing, and there was convergence and low-level equilibrium convergence.(2) Urban-rural integration significantly improved carbon emission performance, and urban-rural integration significantly promoted carbon emission performance in the period from 2012 to 2021 and in the eastern and central regions.Spatial integration, economic integration, social integration and ecological environment integration significantly improved carbon emission performance.(3) Urban-rural integration significantly improved carbon emission performance by stimulating technological innovation, narrowing the urban-rural consumption gap, and improving the element allocation efficiency.(4) Urban-rural integration was conducive to the improvement of local carbon emission performance, and had significant spatial spillover effects, which also promoted the improvement of carbon emission performance in neighboring regions

Abstract：Urban decarbonization is a crucial strategy for achieving the "dual-carbon" goal and fostering sustainable development.Concurrently, the integration of financial technology and green finance constitutes a significant approach to advancing urban decarbonization.Based on established mechanism for the synergistic promotion of urban decarbonization by fintech and green finance, this study conducted a research by selecting 108 prefecture-level cities in the Yangtze River Economic Belt from 2010 to 2021.Utilizing a comprehensive application of the coupled coordination model, kernel density estimation, spatial autocorrelation analysis, and econometric model, we empirically analyzed the spatiotemporal evolution characteristics of the synergistic development of fintech and green finance and examined the mechanism of the impact on urban decarbonization.The results showed that: (1) The synergistic evolution of fintech and green finance within the study area progressed from minimal to moderate coordination, exhibiting "high-high" and "low-high" spatial clustering, and demonstrating a pronounced positive spatial autocorrelation.(2) The integrated advancement of fintech and green finance substantially enhanced urban decarbonization.This effect exhibited regional heterogeneity, which showed the most pronounced in the lower reaches, followed by the middle reaches, and least evident in the upper reaches.(3) Urban industrialization and green technological innovation exhibited both first-order and second-order threshold effects on the synergistic promotion of urban decarbonization, indicating an increasing marginal effect.Drawing on the aforementioned conclusions, we propose certain policy recommendations aiming at establishing a novel green financial system, creating a synergistic framework for urban decarbonization, fostering the advancement of new industrialization, and bolstering green technological innovation.

The Yangtze River Delta (YRD) has the industrial endowment to give full play to the kinetic energy of strategic emerging industries and high-tech industries, and has industrial, technological and market foundations for accelerating the formation of new productive forces. Relevant data of YRD cities were selected from 2016-2022, and the new productive forces of YRD cities were evaluated and analysed by CRITIC-Mutation Level Method-TOPSIS, Dagum Gini Coefficient and Obstacle Degree Model. The findings were as follows: (1) The average annual growth rate of new productive forces in the YRD region was 3.05%. The rate was ordered as Shanghai>Jiangsu> Zhejiang>Anhui, with Nanjing, Suzhou, Wuxi, Changzhou, Hangzhou and Hefei at the forefront of the region; (2) The Gini coefficient between provinces ranged from 0.14 to 0.18, which was at the absolute average level. There was a tendency of expanding for the contribution rate of intra-group differences and hyperintensity; (3) Among the system-level obstacle factors, human capital structure, material and intangible means of production had a greater influence on the new productive forces in the YRD as a whole and in each region. Based on the results of the study, relevant recommendations on intercity linkages and human capital structure were proposed to provide a basis for regional development.

The hydraulic microhabitat of spawning ground of Schizothorax Prenantihabitat is a multi-indicator set.What type of ecological spur dike angle is reasonable in the downstream water-reducing reach after the construction of Jiangshe dam? How to measure whether the water area after the restoration of ecological spur dikes still has the hydraulic characteristics of spawning ground? These issues involve the measurement and representation of more fuzzy concepts.Up to date, the engineers only rely on the accumulation of practical experience or model test to guide the ecological spur dikes angle of different rivers.In this paper, the similarity model of hydraulic microhabitat in habitat spawning ground was established by vague set after restoration, and the similarity standard for microhabitats in spawning grounds after restoration of the habitat of Schizothorax Prenantiwas constructed with reference to foreign spawning ground restoration cases.Based on the two-dimensional hydrodynamic model of average water depth, hydraulic microhabitat of habitat spawning ground of Schizothorax Prenanti in the repaired river section of Jiangshe dam were simulated in terms of water depth, flow velocity, vorticity,and other factors.The effects of different angles and types of ecological spur dikes were studied on the hydraulic microhabitats of habitat spawning ground of Schizothorax Prenanti.Then, the improved vague set was used to verify the repair effect of ecological spur dikes.The research results indicated that the orthogonal L-shaped ecological spur dikes had the best repaired effect when there was a small flow and a certain distance between ecological spur dikes.The results also demonstrated that a larger ratio of the effective length of ecological spur dikes to the effective width of the river facilitated a higher similarity of hydraulic microhabitats after restoration.

In the context of global climate warming, the contribution of agricultural carbon emissions cannot be ignored.Improving the carbon emission efficiency of cultivated land use from the perspective of farmers is the key entry points to achieve the reduction in cultivated land use carbon emission.Based on the micro survey data of farmers in Changde City of Hunan Province, the evaluation index system of farmers' livelihood capital was constructed with reference to the sustainable livelihood analysis framework.The impact of farmers' livelihood capital on carbon emission efficiency of cultivated land use was analyzed by using the stochastic frontier production function model.The results showed that: (1) The overall livelihood capital level of farmers in the study area was not high with obvious differences.The average livelihood capital was only 0.102, which was superior in material capital, human capital and social capital, while there was a need for the natural capital and financial capital to be strengthened; The degree of non-agricultural farmers was high, whose livelihood strategies were mainly part-time and non-agricultural.The structure of livelihood capital of farmers with different livelihood strategies was different.The order of livelihood capital level was: part-time farmers (0.111)> agricultural leading farmers (0.107)> non-agricultural leading farmers (0.093).(2) Livelihood capital had an impact on the cultivated land use carbon emission efficiency.Different livelihood capital structure of different livelihood strategies types had different impacts on the cultivated land use carbon emission efficiency: For agricultural leading farmers, the cultivated land use carbon emission efficiency was mainly positively affected by five livelihood capital; For part-time farmers, it was mainly positively affected by material capital and financial capital; For non-agricultural leading farmers, it was mainly positively affected by material capital and social capital and was negatively affected by human capital.(3)The impact of specific indicators of livelihood capital of different livelihood strategies types was also different.In conclusion, the targeted policies for different types of farmers based on their livelihood capital should be encouraged to improve the carbon emission efficiency of cultivated land use, which included the enhancement of the livelihood capital of agricultural dominant farmers, the encouragement of the livelihood diversification of part-time farmers, and the promotion of the return of non-farmer labor.

Water quality is sensitive to the changes in land use and landscape patterns. To explore the relationship between landscape patterns and water quality at different scales, Changtan Reservoir watershed was chosen as the research object. Based on 2021 water quality monitoring data, buffer zones were divided at intervals of 100m for each inlet tributary. The landscape characteristics of seven strip-shaped buffer zones ranging from 50 to 650m were calculated. Pearman correlation analysis and redundancy analysis were used to study the response relationship between water quality and landscape patterns. The results showed that: (1) The watershed of the reservoir was primarily composed of forest land, followed by arable land and water bodies. The proportion of forest land area increased with the buffer radius, while the proportion of arable land and construction land areas decreased. (2) Arable land, construction land, Contagion Index (CONTAG), and Shannon Diversity Index (SHDI) were positively correlated with water quality indicators, with arable land being a significant source of water pollution in the reservoir area. (3) The explanatory power of landscape pattern on water quality was highest at a 250m radius. Within this range, the landscape fragmentation was high, and the human activities were intense. It is recommended to strictly control farming practices within 250 meters of each tributary. Approaches including the establishment of riparian buffers and the construction of pre-reservoirs should be implemented to enhance the interception of pollutants, and to protect the water environment safety of the Changtan Reservoir watershed. 

In order to further understand the current status of fish diversity in the National Aquatic Germplasm Resources Reserve of Procypris rabaudi and Spinibarbus sinensis in the Jialing River, a field study was carried out in June (summer) and November (winter) 2022.The fish resources in the core area and experimental area of the reserve were comprehensively investigated by combining the traditional fishery resources survey method and eDNA technology.A total of 63 fish species belonging to 44 genera, 9 families and 3 orders were investigated by the two monitoring methods.The Cypriniformes had the largest number of species, accounting for 73.02% of the total species.Analyzed from three ecological types of feeding habits, spawning types and habitat water layers, the fish in the reserve were mainly omnivorous fish (49.21%), fish spawning adhesive eggs (50.79%), and bottom-dwelling fish (46.03%).In terms of diversity indices, the average values of the Shannon -wiener diversity index, Simpson dominance index, Delta + index and Lambda + index of the traditional fishery resources survey method were 2.63, 0.86, 58.89 and 402.8 respectively.The average values of the corresponding indices of the eDNA method were 1.57, 0.60, 59.89 and 348.93, respectively.Both survey methods showed that the diversity index of the core area was higher than that of the experimental area, and the diversity index in summer was higher than that in winter.The T-test results showed that there was no significant difference in the diversity indices of the two survey methods (p > 0.05).One-way analysis of similarity (Anosim) and Jaccard similarity coefficient indicated that there were significant differences in the fish species composition between different habitats (core area and experimental area) and different seasons (summer and winter) in the reserve (p < 0.01) The fish communities were moderately dissimilar.The above results showed that the fish diversity in the reserve was at a general level to a rich level.The similarity of fish species composition between different habitats and seasons was low.In addition, the eDNA technology could be combined with the traditional survey method to complement each other, and it demonstrated a good applicability in the study of fish diversity.

The channel-sandbar system (CSS) is a common geomorphic combination of rivers, and its development and evolution may pose a threat to safety of navigation, water-related engineering, and flood control. The evolution of CSS involves both subaerial and subaqueous parts. Accurately calculating the amount of topographic change remains a challenge in geomorphology. This study took the CSS of Zhangjiazhou reach of the Yangtze River as an example. The joint changes in the volume of subaerial sandbars and subaqueous channel-sandbars were considered. Based on navigation reference plane and the measured water level at hydrological stations, remote sensing images and navigation maps were corrected to a unified elevation reference. An integrated digital elevation model (DEM) for the evolution of CSS volume was developed. The results indicated that this method could efficiently calculate the volume changes of the CSS. From 1993 to 2019, the changes of CSS in the study area was indicated as erosion (12.85 × 106m3 in 1993-2008), siltation (8.14 × 106m3 in 2008-2013), and siltation (15.72 × 106m3 in 2013-2019). Overall, the volume of the CSS in the study area increased by 11.77 × 106m3 during 1993-2019, which was equivalent to 14.12 × 106 t of sediment deposition, using a sediment bulk density of 1.2 t/m3.

Jiangxi Province, recognized as a pivotal demonstration zone in the nation’s ecological civilization construction, plays a crucial role in the ecosystem water production services within the Yangtze River Economic Belt. The ecological services have a profound impact on not only its own development but also on the ecological progress of the downstream regions of the belt. The pattern of ecosystem services is changing under the influence of climate change. To further recognize and understand the impacts of climate change on water production services in Jiangxi Province, the climate change scenario SSPs were coupled with the InVEST model to explore the spatial and temporal changes in ecosystem water production services from 2000 to 2060. A quantitative impact assessment model was constructed to analyze the impact mechanisms. The results showed that: (i) The multi-year average water yield from 2000 to 2020 was 1 234.91 mm, while the projected average yields for the four future SSPs scenarios were estimated to range between 1 386.04 mm and 1 472.99 mm for the period of 2021 to 2060. (ii) Among the four climate change scenarios, the SSPs1-2.6 scenario exhibited the most significant enhancement in water production services, followed by the SSPs5-8.5, SSPs3-7.0, and SSPs2-4.5 scenarios. (iii) The spatial distribution of the water production service in Jiangxi Province due to climate change showed a pattern of high values in the south and low values in the north, with significant spatial variability. (iv) In the four scenarios, the comprehensive index K* of water production services in various cities of Jiangxi Province ranged from 0.04 to 0.28, indicating that climate change was conducive to the water supply services. (v) The impact evaluation model established in this study offered valuable scientific support for ecosystem restoration, biodiversity conservation, and the optimization of water resource management in Jiangxi Province. 

This research focuses on the manufacturing industry and its sub-sectors in 11 provinces within the Yangtze River Economic Belt from 2003 to 2019.The paper utilizes the Super Efficiency SBM model to calculate the carbon emission efficiency.It comprehensively analyzes the dynamic evolution, spatial differentiation, and industry distribution characteristics.Finally, a spatial econometric model is introduced to systematically analyze the convergence characteristics of carbon emission efficiency in various regions.The research reveals the following findings: (1) The carbon emission efficiency of the manufacturing industry continued to improve, and the regional differences in carbon emission efficiency in the upper and middle reaches showed a decreasing trend, and the carbon emission efficiency of the overall Yangtze River Economic Belt and the downstream regions showed a significant polarization; (2) The carbon emission efficiency of the manufacturing industry showed a decreasing distribution of "downstream, midstream and upstream", and the distribution of carbon emission efficiency of the high-carbon manufacturing industry showed spatial heterogeneity.(3) Convergence characteristics are observed in the overall and downstream regions of the Yangtze River Economic Belt.The upstream and midstream regions show no σ-convergence but exhibit absolute β-convergence and conditional β-convergence.The impact of economic level, industrial structure, foreign direct investment level, urbanization rate, and green technological innovation on the change rate of urban carbon emission efficiency has significant heterogeneity. The main paths to enhance carbon emission efficiency in the manufacturing industry include optimizing regional collaboration and productivity layout; promoting the high-end transformation of industrial structure; improving the level of green and low-carbon technology.

Abstract：Green development is crucial for the high-quality development of resource-based cities. This study proposed an evaluation system for green development efficiency（GDE）, using the Theil index, panel quantile regression model, Geodetector to measure GDE in the Yangtze River Economic Belt（YREB）from 2001 to 2021. The spatiotemporal heterogeneity characteristics and associated driving factors as well as their interaction effect were analyzed. We concluded that:(1) The 38 resource-based cities in the YREB all exhibited an M-shaped trend; The upstream resource cities' GDE was marginally higher than that of the middle and downstream resource cities; The growing resource cities' GDE was lower than that of the other three types of cities; (2) The GDE of resource-based cities in YREB tended to have the normal distribution in quantity, resulting in a severe imbalance. The primary cause for the disparity in GDE was the alteration of upstream resource-based cities; (3) The degree of openness to the outside world, the amount of scientific and technological inputs, population density, and the amount of educational inputs contributed largely to the increasing GDE. We concluded that the two driving mechanisms were the “population-economic outward orientation-education” and “population-economic outward orientation-education-technology”, and the two restricting mechanisms were the “economy-transportation-pollution” and “economy-transportation-resources”; (4) Population density had the best interaction effect with the degree of opening to the outside world and the intensity of scientific and technological input. We should focus on the coordinated development of multi-factors, and strengthen the synergistic inter-regional governance to provide a scientific basis for improving the GDE of various resource-based cities in the YREB.

With the transition from the governance of "one lake" to "systemic governance," it is of significant importance to accurately assess the status of household livelihood capital among the farmers in the Erhai Lake basin, in an attempt to propose the optimization strategies for enhancing ecological governance effectiveness in China's plateau lake basin. This is also essential to ensure the livelihood security of households surrounding Erhai Lake basin. This study focused on 369 households across seven towns in the Erhai Lake basin. Based on the Sustainable Livelihoods Approach (SLA) framework, we constructed an evaluation index system for household livelihood capital using the entropy method. The obstacle degree model was applied to investigate the primary influencing factors on different types of household livelihood capital. The findings indicated that: (1) Among the indicators of household livelihood capital in the study area, the material capital index had the highest value, followed by social capital, human capital, and natural capital, while financial capital had the lowest index value; (2) Under the compounded effects of ecological governance of Erhai Lake and natural disease risks, mixed farming households had the highest livelihood capital index and the most stable livelihood channels among the four types of households; (3) The areas where protection policies were applied, household production activities were subject to more stringent restrictions, leading to lower reserves of livelihood capital; (4) The influencing factors of livelihood capital for different types of households were consistent, which included primarily agricultural income, agricultural production equipment, non-agricultural income, arable land area, and household asset value. Thus, the current state of household livelihood capital in the Erhai Lake basin was a result of the combined effect of financial capital, material capital, and natural capital. Household livelihood capital in various types of households within the study area exhibited varying degrees influenced by environmental protection policies, land resources, and other aspects, with a notable spatial heterogeneity. The continuous optimization of various types of household livelihood capital should consider the joint driving effect of multiple elements in conjunction with actual local conditions.

Extreme climate change has a significant impact on the hydrological rhythm of lakes, which further affects the spatial and temporal characteristics of wetland hydrological connectivity (HC), and may promote or inhibit the functional services of wetland ecosystems. The modified nearest water source distance method was used to characterize the HC of Poyang Lake. This method was defined as the nearest distance from any point of land and water to the water-land boundary. The spatial and temporal characteristics of HC and the influence of water level in Poyang Lake wetland were studied using remote sensing images during 2020 to 2022. The spatial differences of HC in the dish-shaped sub-lakes wetland and its impact on the protection of migratory birds were further revealed. The results found that the change of HC was controlled by the lake water level, and the seasonal characteristics of HC in Poyang Lake wetland were obvious. It was indicated that the HC followed a pattern of changing from weak to strong and then to weak, in response to the seasonal transition of lake water level of rising-flooding-falling. The interannual variation of HC was closely related to the lake water regime. Moreover, the interannual variation of HC in the rising and dry seasons was small, while the interannual variation of HC in the flooding and falling seasons was significant. The HC of Poyang Lake wetland demonstrated a spatial pattern of the strongest value in the northern lake area, followed by the value in the northeastern lake area. A larger variability was shown in the southern lake area. Affected by geographical location, topographic characteristics, human activities and lake water conditions, the clustering characteristics of HC for the dish-shaped sub-lakes wetland were obvious. The results confirmed that a moderate HC and large sub-lake area were conducive to the habitat of wintering migratory birds. The three types of dish-shaped lakes represented by Dahuchi Lake, Shahu Lake and Banghu Lake were the hot spots for wintering migratory birds. This study demonstrated that the modified nearest water source distance method was suitable for HC analysis of lake wetlands, based on remote sensing. The research results provided an important reference for the protection of wintering migratory birds in Poyang Lake and the approaches of assessing HC in floodplain wetlands in other areas.

Analyzing the spatial differences and influencing factors of synergistic effects in pollution reduction and carbon mitigation within the ecological construction domain is a prerequisite for guiding regional collaborative governance. It is also a crucial component in achieving the "dual carbon" goals and advancing the construction of a beautiful China. This study employed a comprehensive analysis using the CRITIC weight method，an adjusted coupling coordination model，standard deviational ellipse，Theil index，and a two-way fixed effects model to examine the temporal and spatial evolution characteristics，regional disparities，and the influencing factors from 2010 to 2022. The results indicated that: (1) The overall level of synergy in pollution reduction and carbon mitigation showed an upward trend，with the coordination level gradually shifting from mildly uncoordinated to well-coordinated. (2) The synergy level in pollution reduction and carbon mitigation exhibited significant spatial heterogeneity，with an overall "northeast-southwest" spatial distribution pattern. The distribution center showed a trend of reciprocating migration from southwest to northeast. (3) The overall regional difference in the synergy level first decreased，then increased，and subsequently decreased again. The inter-regional differences were smaller than intra-regional differences，with the overall inter-regional differences manifesting as "midstream > downstream > upstream". (4) The degree of impact on the synergy level was in the order of energy consumption intensity，economic development，technological innovation，industrial structure，and government environmental protection efforts. Among these factors，energy consumption intensity and economic development exerted a negative constraining effect on the improvement of the synergy level，while technological innovation，industrial structure，and government environmental protection efforts had a positive promoting effect.

Taking red culture as the guide to realize the high-quality development of cultural and tourism integration is an important channel for the old revolutionary base areas to actively cultivate and develop new productive forces. This is also of great significance to the revitalization and development of the old revolutionary base areas in the new era. Taking 108 administrative units at county level in the Central Soviet Area of Jiangxi, Fujian and Guangdong as the research units, this study analyzed the spatial and temporal development pattern and future evolution trend of high-quality development of red cultural tourism from 2018 to 2022. The mathematical models such as kernel density, Markov matrix, NICH index and Hurst index were used. The obstacle degree model was further adopted to identify the shortcomings of integration development. The research showed that :①The high-quality development of the integration of red culture and tourism in the study area was stable and. The trend of club convergence and integration was significant, with significant internal circulation dependence and self-adaptability; ②The fusion level presented a semi-enclosed structure of ' core-periphery ' and an increasing trend of ' northwest-southeast ' in space. Based on the core growth point, an extended and radiant growth mechanism was formed, which had strong spatial stability and continuity. ③During the study period, the comprehensive sound quantity heat of the network and the total factor productivity of economic development were the most important shortcomings that restricted the development of high-quality integration, followed by supporting supply, passenger source abundance and environmental regulation, and the short-board factors.

Leveraging the first-mover advantage of the green finance pilots in the Yangtze River Economic Belt is of positive significance for promoting green innovation and high-quality development. Based on the panel data of 108 cities from 2006 to 2022, this study found that green finance had a significant and continuous role in promoting the quality of green innovation in the Yangtze River Economic Belt. The role was more prominent in the upstream basin, non-innovative pilot cities, low-carbon pilot cities and digital economic development pilot areas. Optimizing capital allocation, leveraging environmental subsidies and diversifying innovation risks were the potential mechanisms of affecting the quality of green innovation. Further analysis showed that financial technology, government environmental attention and intellectual property protection played a positive regulatory role. Moreover, under the conditions of moderate environmental regulation and higher education investment, green finance played a greater role in improving the quality of green innovation. These findings were helpful to further understand the unique value and function process of green finance. This study provided objective evidence and policy basis for promoting the quality of green innovation in the Yangtze River Economic Belt.

As a primary national development strategy in the new era, the Yangtze River Economic Belt (YREB) still faces the problem of unbalanced regional development in the current stage.It is of great significance to study the comprehensive carrying capacity of the old industrial cities in the YREB to revitalize them and promote the coordinated and sustainable development.Based on the panel data of 32 old industrial cities from 2012 to 2022, the comprehensive carrying capacity index evaluation system of old industrial cities was constructed.Five dimensions were included, such as society, economy, infrastructure, resources and environment.The Dagum Gini coefficient, optimal parameter geographic detector and spatiotemporal weighted regression (GTWR) model were used.The results showed that: (1) The comprehensive carrying capacity of the old industrial cities increased significantly during the study period, and its mean value showed a trapezoidal distribution of "high in the east and low in the west".(2) There existed development differences in the comprehensive carrying capacity, among which regional differences were the main one that affected the overall differences.(3) It was found that urbanization level, science and technology expenditure, economic development, foreign investment, consumption level, green innovation, and digital infrastructure had apparent driving effects on the comprehensive carrying capacity of the old industrial cities, and the driving interpretation would be significantly improved after the dual effects.(4) The urbanization level had the most significant effect of an increasing trend on the comprehensive carrying capacity.The catalytic role of green innovation and digital infrastructure continued to wane over time.This research provided a reference value for promoting the comprehensive carrying capacity of the old industrial cities in the Yangtze River Economic Belt.

Cross-basin water transfer solves the spatial imbalance of water resources between river basins. However, water transfer may introduce water bodies of different properties into the receiving area, which has an impact on the water quality and water ecology of the local water bodies. The existing studies mostly focused on the impact of water diversion on the upstream ecological environment, but little attention was paid to the impact on the nutrient and organic comprehensive indicators of downstream lake-type reservoirs. Miyun Reservoir, as a lake-type reservoir, is Beijing's surface drinking water source and strategic water reserve base. The impact of the South-to-North Water Diversion Project on its water quality is of particular concern. Based on the primary water quality monitoring data, this study took September 2012 (before water transfer), September 2015 (the start of water transfer), and September 2018 (after water transfer) as the time nodes, and analyzed the quantitative impact of cross basin water transfer on the nutrient and organic comprehensive indicators in Miyun Reservoir. The comparative analysis method was used in this paper. The results showed that the influence of cross basin water transfer on Miyun Reservoir was related to the local water depth. After the operation of the South Water Diversion, the total phosphorus in the deep water area increased by 8.2%, compared to the previous one, which was higher than that in shallow water areas; The total nitrogen showed a downward trend, and the decrease in deep water area was lower than that in the shallow water area. Water transfer enhanced the physical, chemical, and biological activities of water bodies in shallow water areas, and aggravated the pollution trend of reducing organic and inorganic substances in shallow water areas. The concentration of pollutants was found to increase by 34.9%, compared to that in the previous year. After the operation of the Southern Water Transfer, the concentration of chlorophyll in shallow water areas increased by 18.9%, compared to the previous month, and consequently resulted in an increased trend of eutrophication, which was more significant than that in deep water areas.

Maintaining a high quality of water environment is an inevitable requirement for regional integration. The Yangtze River Delta (YRD), one of China's most populous and economically vibrant areas, has raised the bar for aquatic environment management in order to meet the demands of high-quality growth and regional integration. Green finance is an important tool to promote environmental governance. Based on the panel data of 41 cities in China's YRD region from 2011 to 2020, this paper applied the fixed-effects model and the spatial Durbin model to examine the water and environmental governance effects of green finance. It is found that: (1) the development of green finance had a significant positive effect on water environment governance in the region. The relationship between the two remained significant according to the endogeneity exploration and multiple robustness tests. (2) The governance effect of green finance on the water environment was characterized by significant heterogeneity. Cities with high levels of science and technology, economic development, and urbanization had more significant water environment and governance effects from green finance. (3) Green finance can promote water environment management through the mechanisms of industrial structure upgrading, green science and technology innovation, and government environmental governance.(4) Green finance was not always effective in the management of water pollution, and green finance did not show significant beneficial effects on the management of the water environment outside the region, and even the spatial spillover effect was negative and significant. Accordingly, policy recommendations were proposed in terms of encouraging the development of green finance, promoting cross-regional linkages between green finance and water pollution control, and encouraging technological innovation and the development of green industries.

Controlling ozone pollution is a crucial component of the pollution prevention initiatives outlined in China's 14th Five-Year Plan. This study utilized monitoring data (2015 to 2022) of near-surface nighttime O3during the warm seasons, and explored the spatial-temporal variations of the O3 concentrations across the Yangtze River Economic Belt (YREB), with a particular focus on the areas of the Yangtze River Delta, the middle reaches of the Yangtze River, and the Chengdu-Chongqing urban agglomerations. Furthermore, the exposure-response model was applied to evaluate the health risks associated with nighttime O3 exposure from 2015 to 2021. The results showed that: (1) The concentration of nighttime O3 during the warm seasons in the YREB exhibited a fluctuating upward trend, with an annual increasing rate of 0.81 μg簚(m3簚a)-1. Notably, the Yangtze River Delta urban agglomeration experienced the most significant annual increase in nighttime O3 concentration, at a rate of 17.6%. In contrast, the Chengdu-Chongqing and middle reaches of the Yangtze River urban agglomerations demonstrated more modest growth rates, with an increase of 8.3% and 7.8%, respectively. (2) The spatial distribution of nighttime O3 concentration in the YREB revealed a distinct pattern, with elevated levels observed in the northeast and reduced levels in the southwest. Additionally, the number of cities experiencing high nighttime O3 concentrations increased from 33 in 2015 to 44 in 2022. (3) The number of premature deaths that was attributed to nighttime O3 exposure peaked in 2018, and the number subsequently declined, and then experienced a rebound in 2021. By 2021, the mortality rate due to nighttime O3 exposure had decreased by 5% compared to that in 2015. Among the three urban agglomerations, the Yangtze River Delta exhibited the highest number of premature deaths from nighttime O3 exposure, followed by the Yangtze River Midstream city cluster, of which the Chengdu-Chongqing city cluster demonstrated the fewest. Deaths attributed to nighttime O3 exposure in the three urban agglomerations showed a downward trend. This study provided important references for future ozone pollution prevention and control, which was related to policy formulation and public health protection in the Yangtze River Economic Zone.