Exploring the spatial spillover effect of the multidimensional industrial structure on the carrying capacity of resources and the environment is an important way to promote regional coordination and high-quality development in the Yangtze River Economic Belt. Taking the panel data of 108 cities in the Yangtze River Economic Belt from 2003 to 2019 as a sample, based on the entropy method to evaluate the level of resource and environmental carrying capacity from three aspects: resource carrying capacity, environmental carrying capacity, and social and economic support, using Theil index and spatial autocorrelation and other methods to explore the characteristics of its temporal and spatial evolution, and use the spatial econometric model to analyze the spatial spillover effect of the multidimensional industrial structure on the carrying capacity of resources and the environment. The results show that: (1) The overall resource and environmental carrying capacity of the Yangtze River Economic Belt maintains an upward trend, with the characteristics of downstream>overall>midstream>upstream. It mainly comes from the intra-regional differences between the upper, middle and lower reaches. (2) The carrying capacity of resources and environment presents a spatial trend of increasing step by step from northwest to southeast, with significant spatial agglomeration and correlation characteristics. (3) There are differences in the spatial spillover effects of the rationalization of the industrial structure, the service-oriented industrial structure, and the advanced industrial structure on the carrying capacity of resources and the environment. There is a positive spatial spillover effect, but it is not significant. The spatial and temporal heterogeneity of resources and environmental carrying capacity in the Yangtze River Economic Belt is formed under the interaction and accumulation of many factors, including industrial agglomeration, technological innovation, opening to the outside world, and government intervention. In order to realize the first demonstration belt of economic and ecological civilization construction in the Yangtze River, we should pay attention to the spatial spillover effect of resource and environmental carrying capacity between cities, give play to the role of regional synergy and interaction, and promote the spatial adaptation of resource elements.

Urban agglomerations in Yangtze River Economic Zone (YREZ) provide major contribution to urbanization in the region, and assessing the development disparity of the urban agglomerations in this area helps to understand the urbanization in this region. Using NASA’s new generation of night-time light remote sensing product (e.g. Black Marble product), this paper used night-time light growth rate, coefficient of variation (CV), Rank-Size Law and night-time light Gini Coefficient to evaluate the development disparity of the urban agglomerations in this region during 2012-2020. Comparing the urban agglomerations, Yangtze River Delta Urban Agglomeration persists the first position of size in the Yangtze River Economic Zone, and Middle Reaches of Yangtze River Urban Agglomeration has the fastest growth rate, and the Central Guizhou Urban Agglomeration develops apparently faster than the Central Yunnan Urban Agglomeration, while the overall disparity of the urban agglomerations decreased and then returned. For the disparity inside the urban agglomerations, Yangtze River Economic Zone has a clear trend of increased balance, while the trend of the other four urban agglomerations are not obvious. For the inequality among the spatial grids inside the urban agglomerations, Yangtze River Economic Zone has a decreased inequality, while Chengdu-Chongqing Urban Agglomeration, Central Guizhou Urban Agglomeration and Central Yunnan Urban Agglomeration are becoming less equal and the Yangtze River Delta Urban Agglomeration does not have clear trend. It is concluded that the core cities in the Yangtze River Delta Urban Agglomeration has obvious spillover effect, while the effect is not very significant for the other four urban agglomerations although their developments are also rapid. In sum, some possible reasons behind the development disparity of different urban agglomeration have been summarized, and transportation construction and proper development strategy which matches the advantages of the urban agglomeration can help to promote the regional coordinated development of Yangtze River Economic Zone.

Flow space has become an important content in the study of urban agglomeration spatial structure, and how to identify the characteristics of urban agglomeration flow space structure and reveal its impact on the physical space of urban agglomerations is the focus and difficulty of current urban agglomeration spatial structure research. This paper uses the data of enterprises’ off-site investment in 1992, 2001, 2010, and 2019 to construct a city connection network in the Yangtze River Delta. With the help of complex network analysis, K-means clustering and other analysis methods, it explores the evolution of the overall characteristics of the regional economic network and analyzes the evolution law of the network spatial organization structure. The results show that: (1)From 1992 to 2019, the intensity of urban connection in the Yangtze River Delta has increased significantly, and the degree of dispersion and imbalance in the importance and influence of urban nodes has been shrinking. The urban economic networks features small-world network properties more prominently, and the scale-free characteristics are gradually weakening. (2)The urban economic network in the Yangtze River Delta has changed from “V-shaped” structure to the polygonal network structure of interconnected core cities; the network connection has expanded from the interconnection among core cities to the connection among the core city and its surrounding neighboring cities. Spatial proximity network connection features begin to emerge; the participating cities in the network system gradually expanded from core cities to the whole region, and core cities such as Nanjing, Hangzhou, and Hefei formed a relatively independent external radiation network system. (3)The urban hierarchy in the Yangtze River Delta has formed a pyramid structure, with Shanghai as the core city being the most prominent; Hangzhou and Nanjing are the second; Ningbo, Hefei, Shaoxing, Suzhou, Wuxi, Jiaxing and other cities are the third. (4)The development and evolution of the urban economic network in the Yangtze River Delta has gradually moved from the initial development stage and the hierarchical stage to the network stage.

The spatial function division of urban agglomeration is an advanced form of regional division of labor, and exploring its impact mechanism on haze pollution is of great significance for promoting the sustainable and healthy development of urban agglomerations. On the basis of expounding the mechanism of the spatial function division of urban agglomeration affecting haze pollution, an empirical analysis based on panel data of the Yangtze River Delta urban agglomeration. The study found that the enhancement of urban function specialization caused by the spatial function division of urban agglomeration has a significant inhibitory effect on regional haze pollution. Improving the degree of specialization of urban functions will not only help to reduce the level of haze pollution in the region, but also inhibit the haze pollution in adjacent areas. The haze reduction effects of the spatial function division of urban agglomeration is established in the test of central city group, the non-central city group and the non-G60 science and innovation corridor city group; Compared with the central city, the functional specialization of the non-central city group is improved, which has a greater inhibitory effect on haze pollution. The spatial function division of urban agglomeration mainly reduces regional haze pollution through the effect of industrial structure upgrading and labor endowment effect. Finally, the policy enlightenment is expounded from the aspects of constructing the development pattern of complementary functions.

Urban green space is an important components of ecosystem, therefore, studying the evolution of urban green space and its ecological benefits, revealing the mechanism between them can provide a theoretical basis for improving the ecological environment and assisting urban sustainable development. With the help of envi, ArcGIS, ArcView and other relevant softwares, the remote sensing image maps of Hefei Municipal Area is interpreted and classified using the supervised classification. and the evolution of green space and its ecological benefits in carbon sequestration, air purification, soil and water conservation, heat island effect and so on are analyzed. The results show that: (1) the area of green space in Hefei Municipal Area is reduced by 516.59 km² while most of them have been converted to the construction land, which accounts for 74.9% of the construction land area in 2020. At the same time, unvegetated areas and low vegetated areas have increased by 255.5 km² while the urban landscape pattern varies with different functional zoning, and is constantly developing towards fragmentation and heterogeneity. (2) The total ecological benefits of green space in Hefei Municipal Area decreased by 420 million yuan, whil carbon sequestration, air pollutant removal and storm runoff reduction decreased by 177 million yuan, 5.489 million yuan and 261 million yuan respectively. In the meantime, the demand for ecosystem services have increased to 700 times; (3) With the expansion of urban space, the original high-temperature areas around the central urban area and Changjiang West Road spread unevenly to most parts of Hefei Municipal Area Meanwhile, the surface temperature in the study area increased with the decrease of regional vegetation coverage, showing an obvious negative correlation. The area of urban green space in Hefei urban area decreases with the advancement of urbanization, and its ecological benefits also decrease, resulting in problems such as the reduction of ecosystem service capacity, the imbalance between ecological supply and demand, and the strengthening of heat island effect.

Coordinating the trade-offs between ecosystem services is the key for effective ecosystem management and sustainable development. The present study used the ecosystem service evaluation models and monetary evaluation method to evaluate the spatial distribution of five key ecosystem services of Tianmu Lake catchment in 2019, i.e., water conservation, water purification, soil retention, carbon sequestration and product supply services. Then, the synergism and tradeoffs among different ecosystem services were assessed. In addition, a multi objective genetic algorithm (NSGA-Ⅱ) was used for the spatial optimization of water purification service and supply service. The results showed that: (1) water conservation, water purification, soil conservation and carbon sequestration services showed high values in the southern and low values in the northern part of the Tianmu Lake catchment, and exhibited obvious positive correlation with the vegetation coverage. Whereas high values of product supply service were mainly found in the middle part of the catchment and along the river, where tea gardens and cultivated land were densely distributed. (2) synergistic relationships were found for water conservation, water purification, soil conservation, and carbon sequestration services, whereas product supply service showed trade-off relationship with all other services, among which the trade-off relationship with water purification is the strongest and showed as the most prominent contradiction in the catchment. (3) The NSGA-Ⅱ algorithm provided four schemes for the multi-objective optimization of ecosystem services in the study area. All proposed optimization schemes could resolve the conflicting relationship between water quality purification and economic output for a certain extent. The present study could provide new insights and methods for the sustainable management and space layout optimization in Tianmu Lake catchment and other headwater catchments.

Ecological well-being, as the material product and utility provided by ecosystem, is closely related to human survival and development, and its scientific calculation is of great significance to regional sustainable development and the improvement of human well-being. In this study, ecosystem contribution rate was used to study regional ecological well-being of Jiangsu province and analyze its spatio-temporal evolution characteristics which was supported by the ecosystem service theory, and then, GeoSOS-FLUS model was used to predict the land use status of Jiangsu province in 2025, while, ecological well-being circulation and spatial autocorrelation were analyzed based on the change of land use from 1995 to 2025. The results show that: (1) From 1995 to 2020, the total ecological well-being and per capita ecological well-being in Jiangsu province decreased with fluctuation, and the eco-economic output efficiency increased by 540.24%. (2) It was predicted that the total ecological well-being of Jiangsu province will increase slightly, with an improvement of 1.05% compared with 2020. Among the 13 study units, only the total ecological well-being of the three cities in northern Jiangsu decreased slightly. (3) During the study period, the profit of ecological well-being in Jiangsu province was generally lower than the loss caused by the change of land use, which can be explained by the results that water ecosystem was an important contribution type to maintain ecological well-being, and the conversion of cultivated land to construction land was the main reason for the spatial loss of ecological well-being in Jiangsu Province. (4) There was a significant spatial negative correlation between eco-economic output efficiency and per capita ecological well-being in Jiangsu province from 1995 to 2025, but the local spatial correlation was not significantly obvious, which was mainly characterized by low-high cluster and high-low cluster, and mainly concentrated in north and south of Jiangsu province. This study can provide theoretical and methodological references for refined management of regional ecosystem and ecological civilization construction.

The objective calculation of the ecological footprint of water resources in the urban agglomeration in the middle reaches of the Yangtze River was of great significance for assessing the profit and loss of regional water resources and measuring the sustainable use of water resources. In this study, the equivalence factor of the water ecological footprint model was revised according to the “province hectares”. Then, this parameter was applied to the urban agglomeration in the Middle Reaches of the Yangtze River to calculate the water resource ecological footprint and its Spatio-temporal evolution patterns from 2000 to 2019. Finally, based on the Geodetector, the driving factors of the evolution of the ecological footprint of water resources in the urban agglomeration in the middle reaches of the Yangtze River from the four aspects of natural resources, social economy, technological level, and water resources environment was analyzed. The results indicated that:(1) The water resources ecological footprint of the urban agglomeration in the middle reaches of the Yangtze River showed a fluctuating growth trend from 2000 to 2019, with a growth rate of 34.63%. (2) There were significant spatial differences in the ecological footprint of water resources in the urban agglomeration in the middle reaches of the Yangtze River. The water resources ecological footprint in the Wuhan City Group was higher in the north than in the south, and the Poyang Lake City Group showed a distribution trend of “high in the west and low in the east.” The northern and southeastern regions of the water resources ecological footprint in the Chang-Zhu-Tan City Group were higher in the north and southeast than in the central part. (3) The intensity of the ecological footprint of water resources was the main driving factors, and the interaction factors with the highest explanatory power were the intensity of water ecological footprint and GDP. The results could provide a scientific theoretical basis for decision-makers to formulate water resources management policies according to local conditions.

From March to November in 2021, a deep research focuses on the rural settlement plant was carried on in the low mountain and hilly area of the middle reaches of the Yangtze River (Yidu City). The research identified 171 species, 69 families and 147 genera of plants in total. The characteristics of plant community composition in this area were analyzed by flora and frequency index; the research also analyzed and summarized 12 allocation modes based on the investigation of different habitat types in rural settlements. The result shows that the family level flora is mainly distributed in the tropics, of which 35 families are distributed in the pantropic, accounting for 20.7% of the total families; The distribution areas of genus are mainly pantropic(29 genera) and north temperate(28 genera), accounting for 19.7% and 19% of the total genera in this area; The floristic composition of families and genera has the nature of transition from tropical zone to temperate zone; The composite family, Compositae，Rosaceae and Gramineae are the dominant families; The frequently appeared local tree species are Koelreuteria bipinnata， Broussonetia papyrifera，Liquidambar formosana and so on. On the basis of the above research, reasonable suggestions aiming at the selection of plant species and community construction of rural settlements are putting forward from the aspects of species protection, habitat maintenance and ecological restoration for the ecological environment construction in this area. The suggestion also provides reference for the improvement of rural ecological environment in low mountain and hilly areas in the middle reaches of the Yangtze River.

Macrobenthos is usually used to indicate the ecological health of rivers and lakes. The Benthic Index of Biological Integrity (B-IBI) was established based on sampling macroinvertebrates communities at 43 sampling sites (including 8 reference sites and 35 impaired sites) in the river and lake system in Tongling City in August and November, 2020. We have analyzed the distribution range, discriminant ability and correlation of 46 candidate parameters, and selected the number of taxonomic units, the number of gastropoda units, the Margalef richness index, and the number of shredder units as the core parameters of B-IBI index system, in which the ratio method is used to calculate the score value and evaluation standard of each index. The results showed that the average score of the B-IBI is 1.47 in the river and lake system of Tongling City, and the whole river is in the Sub-optimal health. Among the 43 sites, 9 sites were in good health, 14 sites were in Sub-health, 5 sites were in fair condition, 7 sites were in poor condition, and 8 sites were in extremely poor condition. The study can provide scientific basis for ecological health assessment and river-lake management in cities along the Yangtze River.

To better protect Lindera megaphylla and understand its community characteristics and population structure, we investigated the community of L. megaphylla in Zhuxi, Hubei, China. We studied the species composition and diversity of the community, drew the population structure map. We used static life table and population survival analysis to explore the survival status of the population, and used dynamic index and time series analysis to predict its future development trends. Results showed that, the species number and diversity index of the community were low. The species diversity index followed the rank of shrub layer > herb layer > tree layer, and L. megaphylla is the only species in the tree layer . The diameter class structure of the population was irregular pyramid type, and the height class structure was pyramid type. The population was a growing population, but there were fewer young individuals and more middle and old-aged individuals, which showed its high sensitivity to external disturbance. The static life table showed that the number and the life expectancy of individuals decreased with age. The population curves tended to be a Deevey-II type, and the mortality was stable in the early period, but increased in the late period. Survival analysis showed that the population entered the decline stage relatively late, and the hazard rate curve increased sharply at the age class of V and VIII. Time series analysis predicted that the population will continue to decline over time, as the number of older individuals increase over time and young and middle-aged individuals are not replenished. We suggest that, in the future conservation, measures such as replanting or artificial bud promotion should be adopted to increase the number of seedlings. Meanwhile, take measures to reduce destructive disturbances and to strengthen the protection of its germplasm resources.

Landscape ecological pattern is the foundation of regional ecological security and sustainable development. The article takes the shale gas development zone along Wujiang River as an example. Based on data of remote sensing images and shale gas development scale in 2010 and 2020, the mobile window is used to obtain the landscape pattern index, calculate the landscape ecological risk index, and build an ecological network. Explore the direct impact of shale gas development on the regional landscape pattern and the indirect impact of the ecological pattern. The results show that: (1) The forest, cultivated land in the shale gas development zone along Wujiang River have decreased by 52.78 km², 43.78 km² respectively, the construction land grew by 92.04 km². and the grassland and water land remained unchanged. The landscape aggregation index and the largest patch index in the shale gas mining area fell by 9.36%-30.61% and 14.36%-57.69% respectively. The patch density and separation index rise by 25.29%-55.39% and 2.57%-5.11% respectively. The landscape ecological risk index went up by 0.2%-0.52%, from 2010 to 2020. (2) The land damage caused by infrastructure construction such as well sites, pipelines and roads affect the surrounding landscape ecology. Among them, the patch density index and landscape ecological risk index along the road have the largest increase of 50.95%-54.28%, 0.59%-0.62%, the impact on the ecological environment is obvious. (3) In the past decade, the area of ecological sources along Wujiang River has reduced by 250 km², the number of ecological nodes has risen by 10, the length of corridors has increased by 55 km. The obstacles of biological flows, and the instability factors have increased. Shale gas development has enhanced the surface disturbance along Wujiang River with a cumulative effect. As the scale of the well site expands, the landscape and ecological pattern respond significantly. The research provides a new perspective for in-depth understanding of the impact of regional shale gas development on the landscape and ecological pattern, and the development of targeted ecological protection and restoration.

Global climate change mainly characterized by global warming has a great impact on the natural environment and socioeconomic development.As the largest basin in China, the Yangtze River Basin very sensitive to the impact of climate change. Prediction of future climate change can provide important scientific basis to deal with the future uncertainty. In order to make more accurate prediction of temperature and precipitation in the Yangtze River basin in the future, this paper assesses the performance of historical rainfall data and temperature data from the Coupled Model Intercomparison Project phase 6 (CMIP6) over the Yangtze River Basin. The better performed models are selected and corrected. In addition, the future temperature and precipitation in the Yangtze River Basin are discussed. The main conclusions were as follows: (1) The performance of climate models on temperature is better than that of precipitation, and on the time scale is monthly scale > daily scale > annual scale. There is a certain degree of underestimation for temperature simulation and a certain degree of overestimation for precipitation simulation. (2) Regional scale research using climate models is necessary to conduct evaluation and calibration. After evaluating optimization and corrected by seasonal scale, correction of the data accuracy has been significantly improved, witch proves quantile mapping method can be applied to climate model correction of the data, but for extreme precipitation and temperature calibration still exist some shortcomings. In the SSP1-2.6 scenario, future temperature and precipitation changes will continue to increase instably for a period of time, and then tend to stabilize over time. In the other three scenarios, the rate of change accelerated over time. In the future, the precipitation and temperature in the Yangtze River Basin will be higher than that in the historical period under all scenarios, and the performance is SSP5-8.5> SSP3-7.0> SSP2-4.5> SSP1-2.6. Seasonally, the temperature changes greatly in spring and winter, while the precipitation changes little in autumn. Spatially, the regions with higher precipitation increase are mainly located in the headwaters and northeast of the Yangtze River, while the regions with higher temperature increase are mainly located in the upper reaches and headwaters of the Yangtze River. 

The littoral zone is an ecological transition zone between land ecosystem and lake ecosystem, which has great environmental heterogeneity and high productivity, and is also vulnerable to human activities. The littoral zone of Lake Hongze is seriously exploited and utilized. In order to explore the spatial differentiation characteristics of water quality, an extensive sampling survey was conducted at 52 sites in the littoral zone in August 2020, and the driving factors of water quality spatial differentiation were explored by stepwise linear regression. The results showed that nitrogen and phosphorus, permanganate index (CODMn) and chlorophyll a (Chla) were the main parameters affecting the water quality of the littoral zone of Lake Hongze. The total nitrogen (TN) concentrations ranged from 0.66 to 4.25 mg·L^-1, with an average of 1.88 mg·L-1, belonging to grade V according GB3838. Total phosphorus (TP) concentrations ranged from 0.02 to 0.24 mg·L^-1, with an average of 0.12 mg·L^-1, which belonged to grade V. CODMn concentration was between 5.24 mg·L^-1 and 14.16 mg·L^-1, with an average value of 7.21 mg·L^-1, belonging to grade IV; Chla concentration ranged from 4.55 to 158.31 ug·L^-1, with an average of 49.30 ug·L^-1. The spatial differentiation of water quality in the littoral zone were large, with CODMn, Chla and dissolved organic carbon (DOC) were higher in Chengzi area and Western area, but lower in Southern area and East area. There was no significant difference in TN and TP concentrations among different areas owning to great variation within a region. The spatial differentiation of water quality in the littoral zone of Lake Hongze is mainly affected by the buffer utilization type, aquatic vegetation coverage and wind wave disturbance, with the buffer utilization type is the most critical factor.

Agricultural non-point source pollution in Dongting Lake is becoming increasingly serious. It is a scientific issue to understand the spatial and temporal distribution characteristics of nitrogen and phosphorus pollution in Dongting Lake basin.The improved output coefficient model and equal-standard pollution load method were used to calculate the TN and TP pollution load of 25 counties (cities and districts) in Dongting Lake Basin. The spatial distribution map of TN and TP pollution load was drawn with GIS to analyze the temporal and spatial variation characteristics of TN and TP pollution load in the basin. The results show that：（1）From the perspective of spatial scale, TN and TP pollution load on dimensional emissions has obvious regional differences in characteristics, and counties and districts such as Anhua, Taoyuan, Shimen, Pingjiang and Taojiang counties are the key prevention and control areas of agricultural surface source pollution in the Dongting Lake basin, and the areas with higher pollution load are concentrated in the upper reaches of the basin. （2）From the perspective of time scale, the TN pollution load was 11.95, 10.90 and 6.95 ×104 t/a and TP pollution load was 7.60, 7.00 and 4.21 ×104 t/a in 2010, 2015 and 2019, respectively. The TN and TP pollutant loads in the Dongting Lake Basin showed a significant reduction trend, and the TN pollution load was always larger than the TP pollution load. （3）TN and TP pollution load also showed a decreasing law from livestock and poultry breeding, land use and residents' life. （4）Cluster analysis method was used to classify the basin into four types: compound pollution, livestock and poultry breeding pollution, land use pollution and residential life pollution. Finally, in order to promote the comprehensive control of nitrogen and phosphorus pollution in Dongting Lake Basin, combined with the temporal and spatial characteristics of TN and TP pollution loads, some measures were put forward, such as scientific fertilization for planting industry, rational planning of livestock and poultry breeding scale and zoning, improvement of rural living environment, and development of ecological agriculture in accordance with the reality.

In order to deal with the possible water pollution emergency such as ship oil spill in downstream of Xiangjiaba Dam, Yibin river section was taken as a study area, based on the measured topographic and hydrological data, a two-dimensional model of oil spill diffusion was established to simulate the drift path and diffusion area of the oil film after a 20 t oil spill accident occurred on a ship 1 km downstream the dam. Results showed that: (1) During the navigation period, when the outflow from Xiangjiaba Reservoir increased, the time that the oil spill reached different area and pass through different locations was significantly shortened. The time that the oil spill reached to the Pu’an water plant was between 1.58 and 3.05 h, the time that passed through Pu′an water plant was between 0.28 and 0.78 h, the time that reached the Yibin hydrological station was between 3.45 and 8.62 h, and the time that passed through the Yibin hydrological station was between 0.33 and 1.62 h. (2) The diffusion area of the oil spill decreased and the thickness increased with the increase of outflow from reservoir in the process of oil film drift. The oil spill diffusion area that arrived at Pu′an water plant was between 0.141 and 0.224 km², and the average thickness was between 0.351 and 0.491 mm, the oil spill diffusion area that arrived at Yibin hydrological station was between 0.229 and 0.423 km², and the average thickness was between 0.205 and 0.328 mm. (3) The water surface area was small in the dry season, in which the oil film was easy to adhere to the shoals and wetlands on both sides of the curved river during the drift to the downstream. The total area of the oil film adhered to both sides of the river was 0.137 km² when the outflow from reservoir was 1 650 m³/s. As the outflow increased, the area of oil film adhered to both sides of the river became smaller. The research results could provide a scientific basis for the optimization of the emergency rescue plan for the water pollution emergency and oil spill accident in the Yibin river section.

Based on the samples of river water, groundwater, precipitation, and glacier meltwater collected from Lhasa River basin during the dry and wet seasons, the characteristics of sub-basins, such as area, topography, lithology, and glacier coverage for the sampling sites, were extracted. The Piper diagram and Gibbs diagram were used to analyze the controls of river hydro-chemical characteristics by rock chemical weathering, and methods of principal component analysis and correlation analysis were used to reveal the relationship between the main chemical components of river water and the landscape factors of sub-basins. The results show that the hydro-chemical type of river water is mostly HCO₃-Ca, which is mainly affected by the weathering of carbonate rock and the dissolution of evaporative rock. During the wet season, the hydro-chemical characteristics of the river water are also affected by precipitation and glacial meltwater. Generally, the contents of chemical compositions of the river water change with landscape characteristics. With the increase of sub-basin area and the decrease of altitude, the water-rock interaction and carbonate weathering are enhanced, while the dissolution of the evaporative rock is weakened. During the dry period and in glacierized sub-basins, the influence of evaporite on the chemical compositions of the river water is of great significance due to the large areas of sub-basins and the strong groundwater recharge. The study provides a scientific basis for revealing the controlling factors and regional patterns of the chemical characteristics of river water in cold and high-altitude areas.

Land is the resource carrier supporting rural development. The transformation of land use function oriented by sustainable rural development is the necessary requirement to realize sustainable rural land resources utilization. The process of rural development is closely linked to the transformation of land use functions. Based on the survey data of fixed observation points in rural areas of China from 1995 to 2015, this paper quantitatively analyzed the spatio-temporal evolution characteristics and spatial differences of rural land use function transformation in China, and eastern, middle, and western region of China, and discussed the path of sustainable rural development harmonized in China in the future. The results showed that: In terms of time, the social and ecological functions of rural land use decreased from 1995 to 2015, in which the social function was due to the continuous weakening of spatial carrying capacity and employment support, and the environmental function was due to the continuous weakening of environmental purification function. Spatially, the economic, social, and ecological functions of rural land use in eastern and western show obvious spatial differences of advantages and disadvantages. Specifically, employment support and environmental purification in eastern of China, economic output and spatial carrying capacity in central and food supply in western are relatively weak compared with the same spatial functions in other regions. There is a trade-off between economic and social functions, and between economic and ecological functions. There is an intra-group coordination and inter-group trade-off between the two secondary function groups (food supply, economic output, livelihood security and ecological maintenance) and (spatial carrying capacity, employment support and environmental purification). At present, the coupling coordination degree between economic, social and ecological functions of rural land use is mainly in the primary coordination stage and presents a progressive change law from low level to high level coupling. By adopting the multi-functional coordinated transformation and upgrading mode, we can choose the paths of endogenous power and environmental friendliness to comprehensively develop China’s rural areas. Rural regions may be comprehensively developed by selecting multi-functional coordinated transformation and upgrading modes such as endogenous dynamic and environment-friendly.

Rural Industrial Integration Development Demonstration Parks is an important carrier to promote industrial integration, and has the function of cohesion and integration. This paper selects 316 demonstration parks of China’s rural industrial integration development as research units, and uses spatial analysis methods and geographic detector models to explore their spatial distribution characteristics and influencing factors. The results show that: (1) China’s rural industrial integration development demonstration parks are mostly located in East China, and they are spatially cohesive and distributed; on the whole, they show the density distribution characteristics of “small agglomeration and large dispersion” and fractal features of “significant differences in grid dimensions and complex spatial structure”. (2) Seven factors, including the total output value of agriculture, forestry, animal husbandry and fishery, the number of cooperatives integrating production, processing and marketing, and the main business income of the agricultural product processing industry, have a significant positive impact on the number of demonstration parks for the integrated development of rural industries in China. (3) The influence of seven factors, including the total output value of agriculture, forestry, animal husbandry and fishery, and the number of integrated production, processing and marketing cooperatives, on the distribution of demonstration parks for the integrated development of rural industries has spatial differences and there is a two-factor enhanced interaction. Among them, the number of leisure agriculture and rural tourism demonstration counties has the most obvious enhancement effect on other factors.

Tourism use of rural land is one of the important phenomena of land use transformation in suburban rural areas under the background of rural revitalization, and it is an important way to alleviate the contradiction of tourism land and improve the efficiency of land use in rural revitalization. The tourism behavior of rural households is the internal driving force to promote the tourism use of land.Based on the integrated analysis framework of Planned Behavior Theory and Inter-personal Behavior Theory, this research takes 451 rural household survey samples from typical tourist villages in Hangzhou and Changsha as data, and applies structural equation model to empirically test the driving mechanism of rural land tourism use behavior from the perspective of rural transition, so as to reveal the deep law of rural land use transition in the new era. The results indicates:(1) there are five internal logical relationships in farmers’ land tourism use behavior: independent drive of “willing-behavior”, guidance drive of “willing-organizational support-behavior”, economic drive of “behavioral attitude-behavior”, constraint drive of “perceptual behavior control - behavior” and emotional drive of “emotion-behavior”. Among them, the “willing-behavior” autonomous drive plays a dominant role, and the guidance drive of organizational support is the key driving force connecting the will and actual behavior of farmers.(2)Rural tourism economic and social benefit expectation is an important driving force for farmers' behavior and attitude of land tourism utilization, which accords with the dual logic of economic incentive and value pursuit. Normative belief is an important factor of farmers' subjective norms, among which prescriptive norms play a larger role. Farmers' perceived behavior control pays more attention to the consideration of risk assessment and resistance mechanism, resource acquisition and allocation ability and professional skill level. The function cognition of land tourism value and land attachment are the important factors of individual emotional dimension of farmers. The supporting effect of relevant organizations in the level of guidance, implementation, standardization and service is beneficial to promote the transformation of farmers' willingness to behavior.(3) Farmers' land tourism use action has the complex characteristics of rationality and sensibility intermingled, conservative and risky coexistence.Finally, relevant suggestions are put forward in order to provide research reference for strengthening farmers' land tourism utilization behavior and promoting rural tourism sustainable development and transformation development.