The issue of the spatial consistency between tourism resource environmental carrying capacity and land space function is the focus of attention in tourism geography and regional land planning under the background of the construction of ecological civilization. Taking urban agglomeration in the middle reaches of the Yangtze River as an example， the integrated index system for tourism resource environmental carrying capacity and land space function evaluation are constructed. The comprehensive evaluation method，niche breadth model and spatial analysis method are used to analyze the consistency problems between the two. Through empirical analysis，the results show：(1) The spatial distribution of hot spots and cold spots is a far-ranging concentration with local dispersion. Compared with the spatial polarization characteristics of the geographical distribution of socio-economic environmental capacity， the spatial pattern of tourism resource environmental  carrying capacity and tourism resource capacity is more balanced and similar. (2) The six superiority regions of tourism function are combined with industrial development function or ecological service function to form composite functional areas， which cannot be a single leading function in a certain area， that also proves the reliability of the decomposition dimension of tourism resources environmental  carrying capacity. (3) The standard deviation ellipse of tourism resources environment carrying capacity and tourism leisure function is flat and distributed in the southeast-northwest direction， also the shape is more consistent. The geographical contact rate between them is the highest 78.54%， showing a high degree of spatial consistency. Due to the weak of socio-economic environmental capacity or the national ecological protection and other restrictive conditions， the tourism function of some tourism resources and environment carrying capacity with high gradient are not prominent.

Promoting narrowing the urban-rural income gap, is an important part of achieving high-quality development. In the context of the regional integration of the Yangtze River Delta as a national strategy, this article uses the coefficient of variation, Markov chain and spatial analysis to explore the spatial-temporal evolution characteristics of urban and rural income as well as urban-rural income gap between 2000-2018 in the Yangtze River Delta. As well, based on the spatial econometric models, this article explores the driving factors of urban-rural income gap. The results showed that: （1)The coefficient of variation of urban and rural income in the Yangtze River Delta all show a trend of rising first and then declining, urban income is higher than rural but the coefficient of variation of rural income is higher than urban income. The “core-edge” pattern of urban and rural income in space are strong stability. In particular, high-income clubs have a strong steady state. （2)On the whole, the urban-rural income gap also presents a significant “core-edge” pattern. From the perspective of the evolution of urban-rural income gap, the narrowing of the high-value area and the expansion of the low-value area, indicate that the overall income gap of urban-rural income gap in the Yangtze River Delta has narrowed. The difference evolution in different cities indicates that, the policy of narrowing the urban-rural income gap should be tailored to local conditions. (3）For the driving factors, economic development, population mobility, government influence and opening up are important factors of urban-rural income gap. However, the differences of driving factors in different periods indicate that, the formulation of relevant policies in the future should be random and dynamic. In the process of integration and deepening, the significant increase in spatial spillover effects also indicates that, the formulation of relevant policies should strengthen the interaction among cities. The research in this paper not only enriches the theoretical research on the urban-rural income gap, but also provides an experience to formulate relevant policies to promote coordinated development of urban and rural areas for the Yangtze River Delta and other urban agglomerations.

Clarifying the spatial pattern of the distribution of intangible cultural heritage in karst areas is conducive to make an inventory of the current situation of resources and objectively understand the production process of regional culture, so as to improve the management, protection and development level of intangible cultural heritage. Based on the geographical spatial perspective, using GIS spatial analysis method, this paper discusses the type structure, spatial pattern and influencing factors of 1 023 intangible cultural heritages in nine prefectures and cities of Guizhou Province. The research finds that: (1) The types of intangible cultural heritage in Guizhou Province are well-organized, with the largest number of folklore, while Quyi, traditional medicine and traditional art are relatively scarce;(2) The spatial distribution of intangible cultural heritage in Guizhou Province is unbalanced, Guiyang city and Qiandongnan Miao and Dong autonomous prefecture are the dual core, the central and eastern regions are clustered obviously, while the western regions are less distributed;(3) Nearly 90 percent of the intangible cultural heritage in Guizhou Province is concentrated in the low and low-middle karst mountain areas with the altitude below 1 400 m, the proportion of Quyi is the highest. While the distribution of traditional sports, recreation and acrobatics and traditional skills fits well with the main river basins, folk literature has a high correlation with the spatial distribution of main traffic arteries in the Ming and Qing Dynasties;(4) Natural and humanistic factors, such as topography, water system, culture, transportation and economy, have an important impact on the spatial pattern of intangible cultural heritage in karst areas.

The river system plays an important role in the water supply, flood discharge and water purification process of the Taihu Lake Plain. Recently, the urbanization of the Taihu Lake Plain had developed rapidly. A series of human activities such as land-use change and over-exploitation of water resources had resulted in changes in rivers and lakes, and hydrological connectivity had been affected. Furthermore, all these lead to a series of flood and water environment problems. Taking Wu-cheng-xi-yu Region of Taihu Lake Plain as an example, this paper discussed the changes of water system structure and hydrological connectivity in the 1960s-2010s by constructing river system structure and connectivity indicators. The results show that: 11960s-2010s ,With the continuous attenuation of river system, the development coefficient of the river network density and surface rate in Wu-Cheng-Xi-Yu Region decreased by 22.94% and 25.09% and 22.35% respectively, and the complexity of the river network decreased sharply. Among them, the attenuation degree of the river network in Wu-Cheng- Xi region was greater than that in Cheng-Xi-Yu Region. From 1960 to 1980, average hydrological connectivity of the region was 0.89. Average hydrological connectivity of 1980-2000 period fell to 0.82. Average hydrological connectivity returned 0.91 in 2000-2016, which showed a trend of increasing first and then decreasing. Hydrological connectivity between water stations has increased since the 1990s. 3The attenuation of the river structure and the artificial hydraulic regulation artificial hydraulic regulation made the hydrological connectivity decline. And this study will provide support and reference for the utilization and protection of river system in the plain area.

Using the ecological footprint theory and calculation methods, the ecological footprint and ecological carrying capacity of the water resources in the Huaihe River Basin were measured, and five indicators including the ecological footprint of the ecological footprint were introduced. The spatial and temporal changes of water resources in five provinces including Shandong and Hubei were systematically analyzed. The BP neural network with the ability to transform and self-learn can accurately predict the ecological footprint and carrying capacity of water resources in the Huaihe River Basin in 2017-2025. Studies show that: (1) The ecological footprint and bearing capacity of water resources in the Huaihe River Basin are generally on the rise, the ecological deficits and pressures on water resources are too large, and water resources security is threatened. (2) The water resources of all five provinces are in deficit, the ecological pressure index is greater than 1, and the development and utilization of water resources is unsustainable. Among them, Jiangsu has a large load index and small potential for water resources development, and the other four provinces are relatively easy. Development. (3) The forecast results indicate that the ecological pressure of water resources is relatively large, and water resources are in an overexploitation and utilization state most of the time. The supply of water resources is less than the demand for economic development within the basin. In some years, external water needs to be supplemented. The rate is low, and water resources security is in a critical state.

The Su-Xi-Chang region, which is an important grain production base, and is one of China’s fast-growing economic regions. In the context of rapid urbanization, human activities considerably threaten local ecological environments and the land space allocation must be optimized. Based on the data obtained from multiple sources, this study presents the spatial and temporal patterns as well as evolution features of three ecosystem services in the Su-Xi-Chang region from 2000 to 2018, including the carbon storage (CS), food supply (FS), and biodiversity (BD) services, and identifies the interrelations between various ecosystem services using the bivariate spatial autocorrelation method. Results indicate the following trends. （1) CS grew slightly, whereas FS and BD were in the fluctuant downward in the Su-Xi-Chang region from 2000 to 2018.( 2) The spatial distribution of ecosystem services was considerably unbalanced, indicating low and high value distributions in the central built-up area and the surrounding natural land, respectively. Considerably serious degradation can be observed in case of various types of ecosystem services in urban expansion areas.（3) Through tradeoff and synergy analyses, a synergy can be observed between CS and FS as well as CS and BD, whereas a tradeoff can be observed between FS and BD.(4) Spatial differences can be observed with respect to the tradeoffs and synergies associated with ecosystem services. The low-value synergistic zone was concentrated in the city center, whereas the high-value synergistic zone was mainly concentrated in the west and south of the woodland range, with the low-high and high-low value tradeoff areas being spatially distributed around each other. In future, attention must be devoted to the low-value synergistic and tradeoff areas with respect to the ecosystem services in the Su-Xi-Chang region. Furthermore, targeted ecological protection and restoration measures must be developed, and socioeconomic development must be rationally regulated to achieve synergy in case of ecosystem services.

Using MODIS NDVI datasets from 2000 to 2018 as the main data sources, the spatiotemporal variation characteristics of NDVI in Hunan province and its change trend in the future were analyzed, as well as the relationship between NDVI and temperature, precipitation and sunshine duration. The results are as follows: (1) The NDVI of Hunan Province was relatively high with the annual average NDVI of 0.535, and high values of NDVI were mainly distributed in forest-dominated mountainous and hilly lands. The seasonal change of NDVI was significant, it peaked in August (0.674) and reached the lowest in Fabruary (0.363). (2) Generally, the NDVI of Hunan Province revealed a significant increase with the rate of 8.6%/10a during 2000-2018. The areas with significant increasing trend for NDVI accounted for 76.09% of the total study area, mainly distributed in the forest, cultivated land and grassland of central and northwestern Hunan province; And the area with significant decrease trend for NDVI accounted for only 1.46%, mainly distributed in the construction land of Chang-Zhu-Tan area and some field land in Dongting Lake Plain. (3) The NDVI in 76.59% of the study area was predicted to decrease in future, and particularly 23.25% of the area will follow a significant NDVI degradation trend. (4) There was a obvious positive correlation between NDVI, sunshine duration and temperature in winter of the study area.

The Jialing River is the largest tributary of the Yangtze River Basin. In recent years, serious soil erosion has occurred in the Jialing River Basin. The vegetation in the Jialing River Basin has had a relatively large variance in spatial and temporal patterns, affected by the implementation of ecological protection projects and changes in climate. Studying the spatial-temporal change of vegetation coverage and its driving factors in the Jialing River Basin can provide reference for the ecological environment management. This study, based on MODIS-NDVI and climate data, aims to analyze the spatial-temporal change of vegetation coverage and its driving factors in the Jialing River Basin between 2000 and 2019 from multiple angles. Linear regression, Hurst index, coefficient of variation and were employed. AND Mann-Kendall test with partial correlation are both used to investigate the spatiotemporal change of vegetation coverage and its relationship with climate change. The results show that: (1) In the past 20 years, the NDVI of the study area are increased, with a linear tendency being 2.9%/10a, and there is a significant difference in the spatial distribution, showing that the upper and middle reaches are higher and the lower reaches are lower; (2) The vegetation coverage improved area was larger than the degraded area, being 88.68% and 11.32% respectively in the 20 years, The specific manifestation is a significant increase in the southern part of Longnan and southern Shanxi and the eastern part of the middle and lower reaches, and a decrease in the northwest and southern cities, counties and urban areas of the basin; (3) The fluctuation of vegetation coverage in the northern part of the basin is stronger than that in the southern part, and the fluctuation in the central and eastern part is the smallest; (4) The reverse characteristic of vegetation coverage change is significant. In future, the vegetation change showed a continuous degradation trend mainly in southern Luqu County and the southern cities of the basin, and the continuous improvement trend was mainly in Jiange County and Cangxi County of Guangyuan City. The rest of the area showed a trend from degradation to improvement; (5) Temperature has the greatest impact on the change of vegetation coverage in the Jialing River Basin, and there is a time lag effect on the response of vegetation NDVI to temperature and precipitation. The impact of human activities on the change of vegetation coverage is two-sided.

The aquatic plants in Changhu Lake were investigated on January, April, and July and October 2015, the seasonal changes of dominant species, species diversity, and niche width and overlap value of aquatic plants in Changhu Lake were analyzed. The first three important species in winter and spring were Potamogeton crispus (the submerged plant), P. maackianus (the submerged plant) and Typha angustifolia (the water plant). The relatively important value of Nymphoides peltatum (the floating leaf plant) and Eichhornia crassipes (the floating plant) were increased in summer and autumn. The Shannon-Wiener index (H’) and Simpson index (D) were used to evaluate the diversity of aquatic plant in Changhu Lake. The results showed the highest diversity index (H’=2.946 and D=0.940) in summer and the lowest diversity index (H’=0.931 and D=0.428) in winter. The niche widths of the dominant species P. crispus were 0.523 in winter, 0.363 in spring and 0.273 in summer, respectively. The niche widths of other species were less than 0.2. The aquatic plants in Changhu Lake tended to specialized species. In addition, there were also a few species with niche overlap, with 7 pairs in winter, 19 pairs in spring, 23 pairs in summer and 17 pairs in autumn. The species with similar ecological habit and ecological requirements showed the higher niche overlap index, such as between the submerged plants of Hydrilla verticillata and P.malaianus, the floating plants of Azolla imbricate and Salvinia natans, the water plants of Polygonum orientale and P. hydropiper, Myriophyllum spicatum (the submerged plant) and Trapa bispinosa (the floating leaf plant). There was more niche overlap between the dominant specie P. crispus and the other species, 4 pairs in winter and 9 pairs in spring and 7 pairs in summer and only 1 pair in autumn. The ecological niche could better explain the species composition, distribution characteristics and diversity changes of aquatic plants in Changhu Lake. The results showed that the composition of aquatic plant species was simple and the stability of population structure was poor in Changhu Lake.

The plant community survey was conducted on the 1-ha forest dynamics plot established by the Castanopsis eyrei community in Jiugongshan National Nature Reserve, Hubei.The species composition, flora, diameter class structure and point pattern analysis of woody plant in the sample plot were analyzed.The results showed that: (1) A total of 132 species of woody plants（DBH≥1 cm）, belonging to 42 families and 78 genera were found in the community.Among them, Ericaceae, Fagaceae, Lauraceae, Rosaceae and Aquifoliaceae are the dominant families, with Quercus serrata, Rhododendron latoucheae, Cyclobalanopsis glauca, Lithocarpus henryi and Castanopsis eyrei are dominant species; (2) Pantropical distribution of plant families, genera in the communication accounted for the most, respectively with 30.95% and 20.51% ; (3) The diameter class structure of all woody plants in community was an inverted-J shape, the number of small-size individuals is large, and the forest community is in strong renewal status; (4) The spatial distribution pattern of individual woody plants in the plot is mainly aggregated distribution, and some dominant species are aggregated distribution at small spatial scales and random distribution at larger scales.

In order to reveal the spatial variation of soil organic matter and its influencing factors in the arable layer (0~20cm) in mountain areas of Northwestern Hubei Province, Shiyan City was used as the study area to analyze the spatial variation of SOM based on geostatistical methods. And we used Geodetector to explore the influencing factors of the spatial variation of SOM and their interactions. The results showed that the average content of SOM was 17.48 g/kg, which was in a deficient state; the coefficient of variation was 45.59%, which was a medium variation intensity; the Nugget coefficient was 0.496, which was moderate autocorrelation; the anisotropy of the spatial autocorrelation was significant, with the most significant variation in the 45° direction. SOM showed a decreasing trend with decreasing elevation. Annual precipitation, cropping system and elevation were the strongest explanatory and dominant factors determining the spatial distribution pattern of SOM in Shiyan City, while the explanation of parent materials and land use was relatively weak. Two different kinds of factors showed the function of nonlinear enhancement or double factor enhancement. The spatial variability of SOM was the results of the combination of all the factors, which showed the diversity and complexity of the influencing factors of the spatial heterogeneity of SOM in the arable layer. The results can provide theoretical basis for precise management of SOM, improvement of soil quality, and promotion of agricultural production in the study area.

Habitat quality is an important index to measure the habitat function of Yancheng coastal wetland. Under the dual influence of human activities and the expansion of Spartina alterniflora, the habitat quality is threatened. This study took the core area of Yancheng National Nature Reserve as an example, using the InVEST model combined with linear regression equation and the Redundancy Analysis (RDA) to analyze the impacts of human activities and the expansion of Spartina alterniflora on the habitat quality. The results showed that: (1) The human activity intensity index (HAILS) showed a trend of first rising and then declining, with the highest value of 0107 3 in 2006 and the lowest value of 0007 8 in 1992. The area of Spartina alterniflora (ASE) continued to expand, and area percentage increased from 1.673% to 24.930%. In general, habitat quality (HQ) showed a downward trend, from 0.863 to 0.875 in 1983-1992, from 0.739 7 in 2014 to 0.774 8 in 2017. (2) HQ had a significant negative correlation with HAILS and ASE, and the correlation coefficients were -0.940 2 and -0.923 7 respectively. ASE had more influence on HQ than HAILS. (3) RDA ranking can reflect the relationship between HQ, HAILS and ASE. HQ in 10 periods were divided into four quadrants by the variables of HAILS and ASE. The results of RDA ranking were divided into three categories: the first category was in 1983 and 1992 (the first quadrant). The impacts of HAILS and ASE on habitat were relatively weak, and the intensity of their effects was similar. The results in 1997, 2000, 2002, 2006 and 2009 were classified as the second category (the third and fourth quadrants). The influence of HAILS on HQ was greater than that of ASE. The results in 2011, 2014 and 2017 were the third category (the second quadrant). ASE has a greater impact on HQ than HAILS. The results of RDA ranking were with obvious stage characteristics. In 10 periods, the correlation between HQ and HAILS was 1983 ≈ 1992 ＜ 1997 ≈ 2017 ＜ 2000 ≈ 2002 ≈ 2014 ＜ 2011 ＜ 2006 ＜ 2009; the correlation between HQ and ASE was 1997 ＜ 1983 ≈ 1992 ＜ 2000 ≈ 2002 ＜ 2006 ＜ 2017 ＜ 2009 ＜ 2011 ＜ 2014. The results can provide reference for the construction and management of world natural heritage site of Yancheng costal wetland.

The assessment of wetland importance is a basic work of effective management of wetland ecosystem functions. The identification of wetland functional elements is a prerequisite for scientific and objective assessment of the protection value and the importance of wetlands. At the same time, it is an important basis for identifying wetland protection sites and strengthening the effective management of wetland protection sites. Combined with the characteristics of the wetland in Anhui Province, the entropy weight method was used to select 22 indicators from 9 aspects, which including the necessity, rarity, and their regulatory functions and resource functions of the wetland, constructed an index system for the evaluation of the importance of the wetland in Anhui Province. According to the natural fracture method, the wetland in Anhui Province were divided into extremely important, highly important, important and generally important wetlands. At the same time, the principal component analysis method was used to analyze the factors affecting the importance of wetlands. The results show as fellows: The evaluation score of the importance of wetlands in Anhui Province ranges from 0.974 1 to 6.558 8, of which the extremely important wetlands (4.027 1 to 6.558 8) are mostly distributed mainly in the Yangtze River and Huaihe River basins, with an area of about 503 thousand hm ², accounting for the wetlands in the study area 48.29% of the area, highly important wetlands (2.404 9~4.027 0) is about 132 500 hm ², more important wetlands (1.435 1~2.404 8) are about 181 700 hm ², and generally important wetlands (0.974 1~1.435 0) are about 224 000 hm ², scattered sporadically throughout the province; Wetland bird resources, the number of key national protected species, water resources, water quality, and the nature of wetlands are the main influencing factors of the importance of wetlands in Anhui Province. The established evaluation index system and evaluation results could provide a theoretical basis for the protection of wetland protection value, priority establishment of construction and management of grade division in Anhui Province.

In order to explore the influence of the development of navigation junction on Min River in the upper Yangtze River, Tangba navigation junction was selected as the research object which is one of the second order of Min River navigation junction. Analyzing the inflow load in channelized river sections of the reservoir area in accordance with the monitoring data in 2016. Numerical simulation of changes in water quality under three scenarios including before and after the completion of Tangba and in the case of Class III incoming water were performed using MIKE21 model. Then the changes of the pollution zone after the tributary merges was analyzed and the water environmental capacity was also calculated. The results showed that the current source pollution load of the canalized river section in the reservoir area mainly came from the mainstream of the Min River. After completion of construction of Tangba, the CODcr and NH₃-N concentrations meet the Class III water quality standards, and the TP concentration is worse than Class V in front of the dam. In the case of Class III incoming water, the TP concentration becomes Class V. The areas of the polluted zone formed by the tributary flowing into the channelized river section have changed: NH₃-N in Zhenjiang River and Tongche River not form a pollution zone, and the area of NH₃-N pollution in Taihe River decreases, while others have increased. In front of the dam, water environmental capacity of CODcr was reduced by 3 280 t/a, NH₃-N was reduced by 368 t/a, and TP had no remaining water environmental capacity. In the case of Class III incoming water, the water environment of CODcr and NH3-N was decreased. However, the TP had no remaining water environmental capacity. Water environmental capacity of the three types of water quality factors of Tongche River was increased, while Zhenjiang River decreased. There is no remaining water environment in the Taihe River before and after the dam was constructed. This study can provide a scientific basis for the reduction of pollution sources and the designation of countermeasures in Min River.

In order to study the changes of microbial diversity and the correlation between microbial community structure and environmental properties in different periods of time, Fuling County, Zhongxian County and Wanzhou County, the middle section of the Three Gorges Reservoir area, were chosen as the research area. The water quality analysis and 16S rRNA high-throughput sequencing was used to study the microbial diversity of the sampling points during the high water period (January, March) and the low water period (May, July, September) in 2018, and the correlation between microbial community structure and environmental factors in different periods was analyzed. Results showed that the microbial diversity of Fuling in the upper reaches of the middle section of the Three Gorges Reservoir was higher than that of Zhongxian and Wanzhou in the middle and lower reaches. According to the analysis of community composition, the dominant bacteria in the middle section of the reservoir area did not differ significantly at the phylum level. The main dominant bacteria were Proteobacteria(80.50%～21.51%),Actinobacteria(32.60%～9.98%),Bacteroidetes(6.89%～3.50%),Cyanobacteria(9.65%～0.08%), etc. The composition of the microbial community has significant temporal variability, for example, the relative abundance of Actinobacteria, Firmicutes, Planctomycetes and Cyanobacteria was higher in the high water period than in the low water period, while the relative abundance of Proteobacteria was lower in the high water period than in the low water period. Redundancy analysis indicated that total nitrogen, dissolved oxygen and water level were the main environmental factors affecting microbial community structure in the middle section of the Three Gorges Reservoir.

Duliujiang river basin was selected as the research object which was seriously affected by antimony mining activities. The samples of river water and suspended particles in the main and tributaries during the wet and dry periods were collected respectively. Based on the field hydrogeology survey and experimental data, the distribution, migration and transformation of antimony (Sb) in the river was studied, and its speciation and purification mechanism were also revealed. The results showed that the Sb contents ranged from 0.00 to 86.30 μg·L^-1 in wet season and from 5.10 to 487.26 μg·L^-1 in dry season. The dillution effect was stronger in wet season. Because the Sb was mainly from the Sb₂S₃, it had a significant positive correlation with sulfate. The weak alkaline water environment in carbonate area is helpful to the oxidation and dissolution of stibnite (Sb₂S₃) in slag. The dissolved Sb has the main form of SbO^3- which has a strong mobility, and its content decreases along the flow direction and varies with the impact of polluted tributary and secondary release of reservoir sediment. The suspended particle has a purification effect on dissolved antimony. The ratio of dissolved and particulate antimony is between 28-1 180. The concentration of Sb in the exit section decrease to 5.34 μg·L^-1 in wet season and to 9.75 μg·L^-1 in dry season under the dilution of tributary and the regulation of the water control project. Therefore, the Sb content and transmission flux could be decreased through the treatment of contaminated tributaries and with the regulation effect of water control project, and prevent its ecological hazards.

Surface water samples were collected from 22 sampling sites in the main tributaries of Chishui river basin for dissolved trace elements analysis (Al, Fe, Sr, Mn, Cd, Li, and As). The spatial variations and source identification were determined using various multivariate statistical techniques, including correlation analysis, principal component analysis (PCA) and cluster analysis (CA). The results showed that the median concentrations of these elements were in the order of Sr>Fe>Al>Li>As>Cr>Cd>Mn. And the median concentrations of trace elements in study area were match well with the background values of Yangtze River, without significant trace elements pollution in Chishui River. Compared with other trace elements, the relatively high concentrations could be observed on Sr with a median concentration of 540.2 ug/L. Spatial structure analysis showed the high content of trace elements were mainly in the upper and middle reaches of Chishui River basin. The results of factor analysis illustrated that As and Li were mainly from domestic sewage. Mn and Cd were attributed to the cultivation. The source of Al, Cr, Sr and Fe were associated with the rock weathering and domestic sewage. Based on the clustering analysis, four spatial regions were identified: C1 (lower reaches of Chishui River Basin), C2 (middle and upper reaches of Chishui River Basin), C3 (Chishui Heyuan River Basin and Weihe River Basin), C4 (Yanjin River Basin), The trace element concentration of four regions followed by C4>C2>C3>C1. The highest concentrations of Sr, Fe, As and Li occurred in C4; while Mn and Cd in C3, Al and Cr in C2.

Heavy metals in the sediments is not only a huge potential threat to the ecological environment and drinking water reservoirs, also a hot issue in the field of water resources protection. To explore the source of heavy metals in surface sediments and their hazard to the environment on water source reservoirs in Linyi City (Bashan Reservoir, Yunmeng Lake and Xujiaya Reservoir), Shandong Province, the contents of 8 heavy metals (Cr, Cu, Pb, Zn, Cd, Ni As and Tl) were investigated. The spatial distribution characteristics of 8 heavy metals were analyzed, then risks of these heavy metals were evaluated by geo-accumulation index (Igeo) and potential ecological risk index (RI) and the sources were investigated by using principal component analysis and correlation analysis. The results showed that the heavy metals Cr, Zn and Pb in the sediment of Bashan Reservoir exceeded the background value of soil environment in Shandong Province, the heavy metals Cr, Pb and Zn in the sediment of the three reservoirs were all exceeded the standard seriously, Cd slightly exceeded the standard in Yunmeng Lake, and the heavy metals Cu in Xujiaya Reservoir exceeded the standard seriously. According to the evaluation results of Geo-accumulation index and Nemerow comprehensive index, Zn in the three reservoirs was moderately polluted, Pb was moderately polluted in Yunmeng Lake and Cu in Xujiaya Reservoir was slightly polluted, but the other heavy metals were not polluted or lightly polluted. The results of ecological risk index method showed that the average RI of Bashan Reservoir, Yunmeng Lake and Xujiaya Reservoir were 52.05, 59.75 and 61.92 respectively, was less than 150, showing a low ecological risk. Source apportionment results of PCA and correlation analysis indicated that heavy metals in surface sediments from the three reservoirs were mainly affected by three sources. Natural sources, agricultural sources and agricultural activities were identified as the main anthropogenic sources for sediment heavy in this study area, accounting for 36.5%,26.1% and 13.7% of the total contribution, respectively.

Watershed models are cost-effective and powerful tools for evaluating and controlling non-point source pollution, while there is great uncertainty depending on single model simulation which makes multi-model ensemble simulation become inevitable trend. In this study, three nonpoint source pollution models with different structures, named HSPF, SWAT and GWLF, were selected to conduct watershed monthly non-point pollution source ensemble simulation based on Bayesian model averaging (BMA) method, and the expectation maximum algorithm was used to estimate the parameters of the BMA in order to obtain BMA simulation and 90% uncertainty interval. The result using the observed data of the Yixunhe watershed revealed that the Coefficient of Determination and Nash-Sutcliffe Coefficient of the BMA model simulate monthly ammonia nitrogen load and nitrate nitrogen load were higher than that of the single model. The higher the efficiency of a single model is, the greater the weight during the BMA ensemble simulation is. The 90% confidence interval of BMA has a high coverage of measured values in this study. This indicates that the BMA method can not only provide simulation with higher precision through ensemble simulation, but also provide quantitative evaluation of the model structure through confidence interval, which could offer rich information of the non-point source pollution simulation.

Taking the Quasi-natural Experiment of the Farmland Protection Fund in Chengdu as an example, based on the 2005-2018 LUCC remote sensing monitoring data and socio-economic data, the paper estimates the inhibitory effectiveness of the financial compensation policy for farmland protection on the non-agriculture conversion of cultivated land by using PSM-DID method. The results show that: the implementation of the financial compensation policy can significantly restrain the non-agriculture conversion of cultivated land, and this conclusion is still valid after a series of robustness tests; Moreover, with the continuous implementation of the policy, the inhibitory effectiveness of the non-agriculture conversion of cultivated land has gradually become apparent; The financial compensation policy for farmland protection plays an important role in restraining the conversion of cultivated land to urban land, while the conversion of cultivated land to rural residential land has also been avoided. However, it’s not effective for the financial compensation policy to restrain the conversion of cultivated land to traffic roads, airports and other construction land. It is suggested to summarize the experience of pilots for the implementation of financial compensation policy and speed up the construction of compensation mechanism for farmland protection, and as well as to improve the status of farmland protection in the performance assessment of local government to stimulate the inherent incentives for farmland protection.

Based on the survey data of 1 152 farmers in Shaanxi, Gansu and Ningxia, this paper uses the hierarchical regression model and takes ecological knowledge and ecological risk perception as mediation variables, to empirically analyze the impact and its path of media use on farmers' soil and water conservation technology adoption behavior. The results show that: (1) Farmers not only get ecological information through the media, but also acquire ecological knowledge, forming a certain ecological risk perception; (2) Media use not only has a direct impact on farmers' adoption behavior of soil and water conservation technology, but also indirectly affects farmers' adoption behavior of soil and water conservation technology through ecological knowledge and ecological risk perception. (3) Among them, both traditional media and new media have positive impact on farmers' soil and water conservation technology adoption behavior, and ecological knowledge and ecological risk perception play a partial mediating role. The role of new media is greater than that of traditional media. Therefore, we need to pay attention to the education function of the media to the farmers' ecological knowledge and ecological risk perception, so as to promote farmers to adopt soil and water conservation technology.

The recorded microscopic survey data of 979 farmers in Anhui, Jiangxi, Hunan and Hubei provinces is empirically analyzed using Semi-logarithm multiple regression and ordered probit models on the basis of theoretical analysis. The results are shown as following: (1) The eco-production behavior of farmers can be divided into input-reduction and technology-adoption types. (2) A U-shaped correlation is found to exist between the land scale and the input-reduction type eco-production behavior, while a proportional correlation between the land scale and the technology adoption type eco-production behavior. (3) The influencing factors of farmers' input-reduction eco-production behavior are different between small and scale farmers, but there are few differences in the influencing factors of farmers' eco-production behavior of technology adoption between small farmers and scale farmers. Thus, the public knowledge and skills training of farmers should be enhanced. In terms of object selection of public training, the type of business entity and the scale of farmers must be considered. On the basis of content, it is necessary not only to strengthen farmers’ scientific and technical application of pesticides and fertilizer technology, but also to popularize the knowledge of negative externalities of excessive application of pesticides and fertilizers.

Based on the daily precipitation data of 131 meteorological stations in the middle and lower reaches of the Yangtze River Basin between 1961 and 2017. A total of nine indices were selected to represent extreme precipitation characteristics in this area. We studied the temporal and spatial distribution of extreme precipitation in the middle and lower reaches of the Yangtze River Basin and its relationship with the large-scale atmospheric circulation and sunspot by using trend analysis and cross-wavelet transform. This results showed: (1) Between 1961 and 2017, the extreme precipitation indexes increased in the middle and lower reaches of the Yangtze River Basin except for the consecutive dry days (CDD) and consecutive wet days (CWD); (2) Except for CDD and CWD, the extreme precipitation indexes showed semi-circular trends that decreased from the southeast of the basin to three sides, there were significant increases of the most extreme precipitation indexes at Doting Lake Basin, the lower Yangtze River Basin and Taihu Basin during 1961-2017; (3) While the design return period was set up at 50 years, the spatial distribution of all the extreme precipitation indices (except the CDD and CWD) presented the decreasing from the southeast to the northwest, the two anomalous distributions parts may be related to topographical factors; (4) Sunspot was shown as the most significant effect on the extreme precipitation, followed by ENSO, and PDO has the weakest effect. The results of this study can be the foundation for the investigation of extreme climate event driving forces and climate prediction, and provide support for disaster prevention and reduction.

The encounter of main stream and tributary floods has made the river's flood control situation more severe. It is of great significance to analyze the encounter situation of main and tributary floods in order to make full use of the flood control capacity of the cascade reservoirs in the river basin and reduce the flood loss in the downstream. At present, most of the flood encounter analysis is based on the measured data, and copula function has been applied to it because of its flexibility and effectiveness. The purpose of this study is to rationally formulate joint flood control dispatching methods in the various river basins of the Yangtze River and reduce the pressure of flood control in the Chuanjiang River In this paper, we used the multi-year actual measured data of Zhutuo Station, Cuntan Station on the main stream of Chuangjiang River, Beibei Station on the Jialing River and Wulong Station on the Wujiang River. Through Von Mises mixture distribution and P-Ⅲ distribution, this article aims to fit the annual maximum flood occurrence time and flood magnitude. In addition, this paper introduces Archimedean copula function to build joint distribution between main stream and tributary and between tributaries to analyze the possibility of flood encounter in the main and tributaries of the Yangtze River. The results show that: the probability of occurrence of once-in-a-thousand floods encounter in the main stream and tributaries of the Chuanjiang River is low, the probability of the occurrence of the floods encounter between the main stream of the Chuanjiang River and the Jialing River is relatively high and the magnitude is large, while the probability of the occurrence of the encounter between the Wujiang River, the main stream of the Chuanjiang River and the Jialing River is relatively low and the magnitude is small.