As an important region that stretches across the eastern, central and western regions of China, exploring its temporal and spatial characteristics of high-quality development, which exerts great significance on promoting the high-quality development of the country.Based on the panel data of 108 cities in the Yangtze River Economic Belt from 2005 to 2018,this paper first creates an evaluation index system that includes fundamentals of development, social outcomes of development, ecological outcomes of development,and applys the entropy method to calculate its high-quality development level. Then, the spatial imbalance, regional disparity and dynamic evolution trend of high-quality urban development in the Yangtze River Economic Belt are systematically investigated by GIS visualization, Dagum Gini coefficient, kernel density estimation and spatial Markov chain.The results show that: (1) The high-quality urban development level in the Yangtze River Economic Belt has shown an obvious upward trend, and the spatial distribution pattern of high-level agglomeration has evolved from lower reaches to middle and lower reaches;(2) The spatial difference of high-quality urban development is distinct, of which the internal disparity in the lower reaches is the largest, while the disparity between the middle-lower reaches is the largest. During the study period,the overlapping phenomenon of high-quality urban development between regions is always the main source for regional disparity; (3) Without upper reaches, the absolute disparity in the high-quality urban development in the middle and lower reaches of the Yangtze River Economic Belt is expanding, and polarization phenomena exist steadily within each region; (4) Geographical background has significant effects on the high-quality urban development level in the Yangtze River Economic Belt. High (low) level neighborhoods will increase the probability of the city’s own high-quality development status shifting upwards (downwards).The study suggested that promoting the urban development of low-level and strengthing the radiative driving effect of high-level cities are the key points for high-quality urban development in the Yangtze River Economic Belt.

Green innovation is a new driving force for high-quality development, and the spatial differentiation of green innovation efficiency is related to higher-quality integration in the Yangtze River Delta. This paper selects the data of 41 cities in the Yangtze River Delta from 2006 to 2017, uses the SBM model to measure the efficiency of urban green innovation, using Theil index and Hurst index to describe the temporal and spatial characteristics of green innovation efficiency, and selects the Tobit model from “environment-economy-policy” three dimensions to systematically discuss its influence mechanism. The result showed that: (1) The volatility of urban green innovation efficiency in the Yangtze River Delta region is rising, regional differences are gradually decreasing, and the regional coordinated development trend is obvious. (2) Efficient “depressions” has appeared around some core cities in the Yangtze River Delta, and high-efficiency distribution areas have transformed from regions with superior natural endowments to regions with high technical and industrial structure. (3) The green innovation efficiency of cities in the central part of the Yangtze River Delta is at risk of continuing to decline. The eastern coastal zone and the cities in the outer circle of Jiangsu Province are the main areas of continuous growth, which are distributed in bands and rings. (4) Economic factors and policy factors have a higher degree of explanation for green innovation efficiency than natural factors. Factors such as urban economic strength, industrial structure, and environmental regulations play a particularly significant role, but the effects of each factor show phased differences. This has provided scientific support for formulating innovation-driven green development policies tailored to local conditions and promoting higher-quality integrated development in the Yangtze River Delta.

Based on panel data of 71 counties (cities, districts) in Wuling Mountain Area from 2010 to 2018, the modified gravity model and social network analysis were applied to explore the spatial network structure and its effect of tourism economy. The research results show that: (1) During the research period, the strength of the tourism economic ties between counties and cities in the Wuling Mountain Area has been increasing. Especially, the tourism economic links between Wulingyuan District, Zhangjiajie City, Qianjiang District, Bijiang District and other counties have been significantly strengthened, and the integration from point to line to surface is basically realized. (2) The spatial network structure of the tourism economy in Wuling Mountain Area has obvious characteristics. The number of network connections, network density and network efficiency have shown a slight upward trend, while the level of the network has gradually declined. The effective connection of its tourism economy needs to be strengthened. (3) The difference in node centrality in Wuling Mountain Area is converging significantly. The tourism economic network presents a multi-core model. (4) The analysis of E-I index shows the tourism economic network presents “core-edge” structure and “administrative faction structure”. The tourism economy between the four subgroups (sects) of Hubei Province, Hunan Province, Guizhou Province and Chongqing City has increased steadily, but there is a lot of room for improvement. (5) The density of the network is positively correlated with the strength of tourism economic linkages, and negatively related to the difference in the strength of tourism economic linkages. On the contrary, the degree of network level and network efficiency are opposite. The improvement of various indicators of network centrality can significantly enhance the strength of tourism economic linkages.

In order to explore the scale of urban development and its changes, and solve the problem that a single indicator cannot fully characterize the size of cities and towns, the comprehensive rank-scale law is used to study the characteristics of urban size distribution and its changes in Guizhou Province from 2000 to 2015. The results show that: From 2000 to 2015, the scale of Guizhou cities and towns followed the rank-scale law, the concentration distribution index q value was between 1.072 49-1.137 56, which approached the rank-scale ideal value 1. The order of the towns in the middle has changed drastically, and the order of the towns at both ends has hardly changed, showing a monofractal characteristic as a whole. Spatially, it presents a gradient distribution pattern in which cities and towns in the west, north and northwest are ranked high, while those in the east and south are low.The size of Guiyang which is the capital of Guizhou Province, has always been the first, but the urban primacy index is less than 1.3. The ratio of the size of Guiyang to the last towns has dropped from 32.09 times in 2000 to 6.35 times in 2015. The comprehensive rank-scale law can effectively describe the scale of Guizhou cities and towns.The leading role of the first town in Guizhou needs to be further enhanced.

Mineral resources development intensity is an important index to measure regional mining economy. Scientifically identifying the spatiotemporal evolution characteristics and influence factors of the development intensity of mineral resources is of great significance for the sustainable development of regional economy. This paper combined mining right, output scale, exploitation area to measure the development intensity of mineral resources in the Yangtze River Economic Belt from 2006 to 2017, and discussed the spatiotemporal evolution characteristics and influence factors of the development intensity of its mineral resources. The results show that: (1) Mineral resources development intensity in the Yangtze River Economic Belt is on the rise on the whole, and presents significant spatial distribution with a spatial pattern of being high in the southwest and low in the northwest; (2) The overall gap in the development intensity of mineral resources in the Yangtze River Economic Belt is widening, and intra-regional differences are greater than inter-regional differences, among which the internal differences in the upstream region account for the largest proportion; (3) Mineral resources development intensity in the Yangtze River Economic Belt presents a significantly positive spatial correlation which keeps increasing; (4) Mineral resources development intensity is affected by resource endowment, ecological environment, social economy and other factors, among which the reserves of mineral resources, the importance degree of the ecological environment, GDP per capita and labor input are the main factors affecting the change of mineral resources development intensity in the Yangtze River Economic Belt.

 The service function of water retention is central in the ecosystem service function. The quantitative evaluation of water retention function can provide reference for the evaluation of regional ecological environment quality. Based on InVEST model with localized parameters analyzed the temporal and spatial changes of water retention year by year from 2000 to 2019 in Anhui Province and the differences of influencing factors under different climatic conditions. The results showed that in the past 20 years, Anhui Province water retention service function has enhanced. The spatial distribution pattern of water retention depth is high in the south and low in the north. The depth of water retention in the Qiantang River Basin is greater than that in the Yangtze River Basin, and the depth of water retention in HuaiHe River Basin is the lowest. The average annual water yield depth of Anhui Province was 763.1mm, the average annual water yield was 10.65×1010 m³, the average annual water retention depth was 193.7mm, the total amount was 26.8×109 m³. From the land types, grassland water yield capacity was the strongest, woodland water retention capacity was the strongest. In the dry years of 2001, normal years of 2008, and wet years of 2015, there was no significant difference in the q ranking of the explanatory strength of the water retention function among all factors, and the intervention intensity of human activities on the water retention service function was constantly increasing.

The community structure and influencing factors of macroinvertebrate in the Hongze Lake were systematically studied in April and September 2018. The results showed that 37 species of macroinvertebrate were identified, belonging to 4 families, 8 classes, 13 orders and 19 families. The dominant species were Limnodrilus hoffmeisteri, Gammarus sp., Nephtys oligobranchia, Microchironomus tener, Corbicula fluminea, with dominances were 0.108, 0.068, 0.054, 0.037 and 0.020, respectively. Species richness, Margalef diversity index and Shannon index were significantly higher in April than in September. Non-matric multidimentional scaling ordination (NMDS) and PerMANOVA confirmed the difference of benthic community during the two surveys. Indicator species analysis showed that Harnischia fuscimana, Microchironomus tener, Teneridrilus mastix, Laonome sp., Branchiura sowerbyi were the key species responsible for the difference of macroinvertebrate community between the two surveys. Distance-based redundancy analysis (dbRDA) was used to identify the key factors affecting macroinvertebrate community structure; and the results showed that the community structure was mainly affected by conductance, water temperature, chlorophyll a and silicate in the April; while, the key factors affecting macroinvertebrate community in September were phosphate, water depth and dissolved oxygen. This study lays a data and theoretical foundation for further research on macroinvertebrate ecology of the Hongze Lake and evaluation of the impact of inter-basin water transfer on freshwater ecosystem.

Habitat suitability assessment of the free-ranging Père David’s Deer (Elaphurus davidianus) in Shishou Milu National Nature Reserve is very important for conserving and restoring species diversity. From May to August 2019, presence data of Père David’s Deer in the nature reserve were obtained by aerial photography and field survey. Based on the Google Earth images in May 27th, 2019, the object-based random forest classification method was used to classify the habitat types. Then we utilized Maximum Entropy (MaxEnt) model to assess the suitability of habitat in summer. Results showed that the accuracy of the MaxEnt model was excellent (mean AUC is 0.910). The distance from the bareland, the mudflat, and the forest were the main environmental factors influencing habitat suitability for Père David’s Deer, with contribution rates of 35.2%, 34.5%, and 15.7% respectively. The sensitivity analysis of habitat factors showed that with the increase of the distance from mudflat、bareland and forest, the habitat suitability and the occurrence probability of Père David’s Deer both decreased. The suitable habitat area was 338.84 hm², accounting for 27.41% of the whole core area. Areas with a high suitability for Père David’s Deer were mudflat, grassland and bareland, which located in the central and southern region of the Nature Reserve. Results from our study suggest that the managers need to build a diversified landscape in the reserve and establish new ex-situ conservation area in the middle Yangtze basin.

In order to coordinate the development between water environment carrying capacity and regional economy, the system dynamics method (SD) was used to model the water environment carrying capacity in Baiyangdian Basin which includes 17 refined industrial industries and is constrained by multiple factors of water resources, water pollution and water ecology. Thirty-two sensitive indicators were obtained from sensitivity analysis of SD. Taking local practical development demand into consideration, 6 control scenarios which are applicable to the carrying capacity of water environment in Baiyangdian Basin were set, and the simulation along with the regulation results of water environment carrying capacity from 2017 to 2035 in Baiyangdian Basin were obtained: (1) If the present status is maintained, population and economic growth will arouse increasing demand for water resources and bring more water pollutants. Consequently, there will be a water resource gap which may further increase after 2020 and the water pollution will be worsen after 2021. (2)Compared with the current scenario, industrial structure adjustment or water environment protection could improve the overload of water environment in Baiyangdian Basin by 10.78% or 10.42% and increase the GDP by 0.22% or 0.26% in the future. However, the sustainable development scenario which considers the coordinated development of economy and environment is more favorable. When the GDP increases by 0.22%, the improvement of the water environment overload situation could reach 16.23%, which means the improvement effect is more distinct. If more stringent water environment protection measures are taken, the improvement effect may reach 34.56%, but the GDP will decrease by 5.06%, and the economic development will be greatly restricted. (3)Based on the above analysis, the overall planning must be conducted. High-end, high-tech and service industries should be vigorously developed, the scale of primary and secondary industries should be rationally reduced, and the scale of livestock breeding should be regulated. Meanwhile, the development scale of high water consumption and heavy pollution industry such as textile, paper and paper products should be restrained while cleaner production technology for industry improvement and innovation should be adopted. Multiple water supply mechanism should also be established to guarantee the water level in Baiyangdian and reduce groundwater exploitation. Water pollution treatment facilities and the rate of water resource utilization and sewage reuse should all be improved too. Moreover, forests and wetlands need to be restored and high-standard pollution control should be performed in Baiyangdian Basin so as to coordinate the development of economy, population and environment.

 Effectively identifying the priority pollutants of the water environment is an important aspect of constructing a coordinated water environment monitoring system in the Yangtze River Delta Integration Demonstration Zone. Entrophy Method and TOPSIS method were used to screen the priority pollutants from 80 specific pollutants other than basic monitoring items in “Surface Water Environmental Quality Standard” based on the quarterly 109 full-indicator monitoring data from 2017-2019 of the Taipu River, which is an important transboundary river in the integrated demonstration zone, with four evaluation indicators such as the frequency rate, spatial distribution, maximum occupancy rate and carcinogenicity .The results show that: (1) The risk of antimony is high; the risk of nickel, dichloromethane, and acrylamide is relatively high; the risk of cobalt, titanium, boron, sulfide, atrazine, microcystin-LR, 1,4-dichlorobenzene and chlorobenzene is average. (2) At present, the water administration and data management in Wujiang in Jiangsu, Jiashan in Zhejiang, and Qingpu in Shanghai are significantly different from the water environment co-governance goal of “unified standards, unified monitoring, and unified law enforcement”. (3) Based on the monitoring status of the demonstration area and the identification results of priority pollutants, this study puts forward some water monitoring recommendations for the Yangtze River Delta Integration Demonstration Zone from the perspectives of “improving monitoring indicators and information disclosure”, “improving coordinated monitoring and data sharing”, and “improving the integrated water environment early warning system”.

Delineating the ecological protection red line (EPRL) is of great significance in coordinating development of territorial space and eco-environment protection, which is key to safeguarding national and regional ecological security. This paper applies six indicators from two aspects of ecosystem services and ecological sensitivity to evaluate the current status of the ecological environment in Jiangsu Province. We further establish a niche-fitness model to assess the matching degree between the actual ecological niche and the ideal ecological niche of the EPRL. Then the terrestrial EPRL is spatially delineated in Jiangsu Province. The results show that: (1) The area of extremely important zones of ecosystem services accounts for 18.83% of the total area of Jiangsu Province which are mainly distributed in the low hill in southwest and north of the province, marsh regions among Huai River and the Tai Lake basin. The area of extremely ecological sensitivity zones occupies 6.96% of the total area of the province, showing an obvious spatial distribution pattern of “more in the south and less in the north”. (2) The total area of EPRL on the terrestrial parts covers 17 406.68 km²,and the area of rigid EPRL and elastic EPRL accounts for 57.28% and 42.72%, respectively. (3) The spatial distribution of terrestrial EPRL presents a pattern of “one horizontal, one vertical and three regions”, which primarily includes the Yangtze River, the lake groups of the Chinese Grand Canal, the low hill areas in southwest and north of the province, and marsh regions among Huai River. Niche-fitness model can be used to effectively assess the suitability of ecological space and provide a scientific method to depict the EPRL. Hence, the results of this paper can provide a quantitative reference base for depicting and optimizing the terrestrial EPRL in Jiangsu Province.

To optimizing the environmental policy making and implementing.Logical analysis frame including evaluated multiple dimensions environmental performance,analyzed multiple scenario and multi-agent implement were designed.Taking Nanjing as example,multiple dimensions environmental performance of Nanjing from 2003 to 2018 was evaluated,three different development scenarios were designed, and the policy demand and paths of high quality of ecological environment were analyzed, and based on the stakeholders theory multi-agent implement was structured.The results show that, the quality of atmospheric environment was better than the city of Beijing-Tianjin-Hebei region,and was worse than the city of Pearl River Delta.There is a growing tendency in environment quality of PM2.5 and PM10 ,but they were not up to the second of atmospheric environment standard（GB3095-2012）,and O3 become more and more polluted, There is a growing tendency in environment quality of water environment,and no worse section than V quality.The decoupling condition between industrial economic and waste water and solid waste emission were in the condition of decoupling in general from 2003 to 2018,but exhaust was in the condition of coupling.The environmental performance of power plant is good,and chemical industry and ironworks is worse.Based on the high target of Yangtze Economic Belt with ecological environment high quality in 2025, coordinated development should be accepted,multiple pollutants should be in synergetic treatment,and multi-agent involving government,company and public should be in cooperative governance.

With the acceleration of regional collaborative integration, the shortage of soil and water resources along with the degradation of ecological environment have brought great pressure to the high-quality development of cities. Constructing the regional ecological security pattern is regarded as a effective way to alleviate the contradiction between ecosystem protection and social development. Choosing Southern Jiangsu urban agglomeration as the studying subject, the paper identifies ecological supply source by the combination of MSPA method and landscape connectivity assessment. Besides, the ecological demand source is selected by the ecological scarcity evaluation. Further, extracting the ecological corridors coupling supply and demand space by applying the minimum cumulative resistance model. Finally, setting the strategic points and landscape ecological security pattern was then constructed．The results show that (1)The total area of the ecological supply source is 4 876.76 km², accounting for 17.36% of the study area. The total area of ecological demand sources is 2 099.8 km², accounting for 7.48% of the study area.(2)55 ecological supply corridors and 199 ecological supply-demand corridors are constructed, with a total length of 2 296.95 km.(3) 98 strategic points were obtained as the key spatial nodes of urban ecological construction in the future. The research can offer references for the Yangtze River Delta region, which includs the Southern Jiangsu urban agglomeration, to optimize the territorial space development pattern under the guarantee of ecological security. Also, the research provides a reference for the construction of ecological security pattern of other high-density urban agglomerations in China. 

Based on the InVEST model, Assessment of habitat quality using GlobeLand30 land cover data for the third phase of Qinling-Daba Mountain, Shaanxi Province, The topographic gradient effect is studied by using topographic factors. The results show:(1)2000-2020, Land use change in Qinling-Daba Mountain area of Shaanxi Province is mainly cultivated land to construction land, and the mutual transformation between cultivated land, woodland and grassland; (2) The average habitat quality of Qinling-Daba Mountain area in Shaanxi Province in 2000,2010 and 2020 is 0.868 9,0.867 5 and 0.864 0, A sustained decline; 20 a, The area of high habitat remains stable, Large increases in the area of low habitats, Growth of 945 km²over the period 2000-2020 (3) The high habitat quality areas are mostly located around the Qinling Mountains in the northern part of the study area and the Dababa Mountains in the southern part, The lower habitat is mainly distributed in Xi'an, Hanzhong and Ankang three towns and surrounding areas; 2000-2020, The temporal and spatial evolution of habitat quality in Qinling-Daba Mountain area of Shaanxi Province is stable, The situation of local deterioration; (4) The distribution of habitat quality in Qinling-Daba Mountain area of Shaanxi Province has significant topographic gradient effect, Low habitats have strong distribution advantages over low topographic gradients, Higher habitats dominate the high gradient, The distribution of habitat quality is greatly affected by topography. Therefore, Depending on the topography of different habitat types, Proposing targeted biodiversity conservation measures, The results can provide theoretical reference for habitat protection and planning of Qinling-Daba biodiversity ecological function area in Shaanxi Province.

In February (dry season) and July (wet season) 2018, the spectral absorption and three-dimensional fluorescence spectrometry analysis of chromophoric dissolved organic matter (CDOM) in Lake Fuxian and its inflowing rivers have been performed to clarify the CDOM’s sources, composition and their spatiotemporal characteristics.The values of a(254) ranged from 3.58 to 4.66 m-1, indicatinglow CDOM abundance. The fluorescence index FI (1.51-1.89), biological autochthonous index BIX (0.81-1.24), freshness index β/α (0.76-1.14) and the humification index HIX (all less than 4 except for HD7 and HD13 during thewet season) of Lake Fuxian and its inflowing rivers,indicated that the CDOMwas mainly autochthonous with a low degree of humification.Five CDOM components were identified by using the parallel factor analysis, including two humus-like components (C1, C2), two tyrosine-like components (C3, C4) and one tryptophan-like component (C5). The CDOM of the inflowing rivers, nearshore and offshore areas of Lake Fuxian during the dry season showed tyrosine-like fluorescence characteristics. However, the CDOM of the inflowing rivers during thewet season showed humus-like fluorescence characteristics.During the dry season, the autochthonous components and their proportion (C3+C4) of Lake Fuxian had larger values. However, in wet season, the allochthonous components (C1+C2+C5) and the HIX were larger. These results indicated the sources of CDOM transformed to allochthonous during the wet seasons. River inputs had few direct contributions on the CDOM abundances of the lake. Due to the strong light radiation, large water storage, long hydraulic retention time and its secondary effects (e.g., microbial actions), CDOM autochthonous components of Lake Fuxian was still up to 45% in the wet season. Furthermore, the varies of BIX、β/α、M in different areas of Lake Fuxian implied that the influences of seasonality on CDOM had spatial heterogeneity.

Identifying soil moisture transfer processes in permafrost influenced hillslopes is a key to understanding runoff generation processes in cold region. Isotope technology can obtain the information of hydrological process without destroying the original structure of soil. In this study, precipitation, groundwater, river water, and the soil water were collected during the thawing period of active layer (the thawing depth was about 100 cm) in a typical hillslope of permafrost watershed. The stable isotope characteristics of different water bodies was analyzed to explore the regularity of soil water migration in the source region of the Yangtze River (SRYR). The results indicated that, the variation of soil water δ18O was -14.58‰ ~ -1.58‰ (mean -8.25‰), the δD was -103.88‰ ~ -14.99‰ (mean -59.94‰). The isotopic component of soil water, river water and groundwater were all distributed near the local meteoric water line (LMWL), indicating that precipitation was the main source of these water bodies. The slope and intercept of evaporation lines were lower than that of LMWL, and the slope of groundwater evaporation line (GWEL) was the lowest, and it showed a heavy isotope enrichment, which indicated that the groundwater had experienced a certain degree of evaporation in the process of migration and transformation under the influence of evaporation and mixing effect. The complexity structure system of root layer made the soil water isotope show the most great variation and also had a heavy isotope enrichment phenomenon. The low d-excess value of the root layer indicated that it undergo a strong evaporative fractionation process. Except for river water, other water bodies had a greater temporal changes during the study period. Precipitation had little impact on soil water isotope compositions, while groundwater and soil water at 20~50 cm depth dominated the contribution of river water. This study has a positive significance for understanding the process of runoff generation and concentration in cold regions, and also provide basis for simulation and prediction of runoff process in cold region.

Designing an early warning system for cultivated land ecological security can help us make advance analysis and warnings for the ecological security of cultivated land, which plays an important role in guiding the rational use of regional cultivated land resources and formulating scientific and reasonable agricultural development policies. From the perspective of the PSR model to construct an index system, this paper uses the entropy method and multi-factor comprehensive weighting method to evaluate the ecological security of cultivated land, and then proposes an integrated model of random forest and multi-layer neural network (RF-MLP integrated model) to predict the level of ecological security of cultivated land, and finally the early warning system for cultivated land ecological security was constructed. We used the main grain producing areas in China as an example to verify the system. The system runs smoothly, the accuracy is qualified, and the reliability is high. It has made a useful attempt to realize the commercial operation of cultivated land ecological security monitoring and early warning, and it has strong application value. The results show that: (1) The early warning system built with the RF-MLP integrated model as the key technology uses the random forest model to optimize the input attributes of the multi-layer neural network, which not only optimizes the selection of relevant features to improve the prediction accuracy of the model, but also avoids excessive features leading to over-simulation. It has made a useful attempt to realize the commercial operation of cultivated land ecological security monitoring and early warning. (2) The application results show that the ecological security value of cultivated land from 2006 to 2017 showed an overall upward trend, but the growth rate was not high. the warning level is changed from medium to light, and the spatial pattern of the warning situation shows the distribution pattern of the northern provinces with higher warning level than the southern provinces. From 2018 to 2027, the ecological security of cultivated land in major grain-producing areas has been improved, but the warning level remains at light warning. During the forecast period, the spatial pattern of the warning situation has basically stabilized. In some areas, such as the Northeast and the Huanghuaihai Region, the cultivated land ecology has great potential to develop in a positive direction. However, although the cultivated land ecological security in the middle and lower reaches of the Yangtze River is generally great, the security value has declined somewhat, and the warning level has changed from no warning to light warning.

The ecological environmental protection and high-quality development of the Yellow River Basin have risen to a major national strategy. It is of great practical significance to explore the coupling and coordination between tourism and eco-environment ,which promotes regional high-quality development. The index weights were determined through SEM, and tourism and eco-environment system were established. Combined with coupling coordination and interactive coercion model explored the coupling and coordination spatial-temporal evolution and interactive stress from 2008 to 2017. The results showed that: in timing changes, the coupling level was high（>0.8） and the fluctuation was not obvious, the overall coupling coordination degree showed a “W”-shaped fluctuation in a small range, but the relative lag of the tourism development evaluation index made the degree of coupling coordination in a barely coordinated state; in terms of spatial evolution, there were obvious differences between upstream, middle, and downstream, which is manifested as a spatial pattern of “high in the southeast and low in the northwest”. The degree of coupling coordination transited from downstream intermediate coordination, midstream primary coordination to upstream imbalance. The relative development types had obvious spatial differentiation. The downstream was the lagging type of tourism development, and the middle and upstream was the lagging type of ecological environment; two systems also conformed to the double exponential function model, and there was an interactive stress relationship between them. Provinces can strengthen regional cooperation in tourism environmental protection and optimize the structure of tourism development to promote the coordinated and high-quality development of the tourism industry and ecological environment in the Yellow River Basin.

As the core area of China's economic development and an important agricultural production base, the Yangtze River Economic Belt is confronted with great risks and challenges in the process of rapid urbanization and industrialization, with large load and significant pressure of cultivated land resources. Based on the cultivated land pressure index model modified by the standard cultivated land coefficient, this paper analyzes the cultivated land resources situation of the Yangtze River Economic Belt from 1987 to 2017, reflects the changing trend of the cultivated land pressure with multiple spatial and temporal scales, and calculates the future changing trend of the cultivated land pressure by using the prediction model.The results show that :(1) The time series of cultivated land pressure in the Yangtze River Economic Belt presents an inverted "V" type distribution, and decreases slowly after reaching the peak pressure in 2003; The spatial pattern presents the basic situation of "overall stability and local turbulence", and the pressure center of gravity moves to the east. (2) The regional cultivated land pressure is obviously heterogeneous. The upper reaches of the Yangtze River are mainly affected by poor farming conditions and frequent natural disasters, while the lower reaches of the Yangtze River are mainly affected by rapid urbanization. The distribution pattern shows the situation of "rapid rise in the lower reaches, steady decline in the middle reaches and fluctuation in the upper reaches". (3) During the 14th five-year Plan period, the cultivated land pressure in the Yangtze River Economic Belt has not been alleviated, and has a momentum of increasing year by year, which poses a certain challenge to the great protection strategy and needs to be taken seriously by relevant decision-making departments.

Soil moisture plays a vital role in the hydrological cycle and climate system. It is very important for agricultural drought monitoring and prediction. This paper selects ESA CCI soil moisture data from 1979 to 2019, and uses the Pearson correlation method to verify the correlation of CCI products with in-situ observation data. This paper uses standardized soil moisture index method to classify agricultural drought levels, uses wavelet analysis, Mann-Kendall and Sen slope trend test to study the historical spatio-temporal evolution of agricultural drought in the Yangtze River Basin. The results showed that the area of agricultural drought in the Yangtze River Basin increased first and then decreased. In season, drought is prone to occur in spring and winter. 28, 12, 22, and 32 years are the main periods of drought. The severe drought center had a downward trend at latitude and eastward trend at longitude. The southern part of Jinsha River Basin, the northern part of Min River, Tuo River and Jialing River Basin, the Han River Basin, the upper Yangtze River, the Wu River Basin, and the western part of Dongting Lake Basin have obvious drying trend. The source of the Yangtze River, the eastern part of Dongting Lake Basin, the Poyang Lake Basin, the middle and lower reaches of the Yangtze River, and the Tai Lake Basin have obvious wetting trend. The rest of the Yangtze River Basin remains stable. From the perspective of long-term soil moisture, this article explores the spatio-temporal evolution of agricultural drought in history, and provides a new monitoring method for accurate agricultural drought monitoring and early warning.

It is of great significance to explore the coupling coordination relationship and evolution trend of the agricultural eco-economic system for scientific evaluation of ecological governance benefits and realization coordinated development of agricultural eco-economy in the karst area. Taking Guizhou Province as an example, based on the data of agricultural ecological environment and agricultural economic development, this paper constructs the evaluation index system of agro-ecological system and agro-economic system. Using entropy weight method, coupling coordination degree model and coupling degree model, we quantitatively analyzed the comprehensive evaluation index, state of coupling coordination, and trend of coupling degree evolution of the agro-ecological system and agro-economic system in Guizhou Province from 2000 to 2019. The results showed that the comprehensive evaluation index of agro-ecological system presents a trend of first decreasing and then increasing in Guizhou Province, but the agro-economic system maintains a steady rising trend, and the relationship between the two is gradually evolving from “economic lag type” to “ecological lag type”. The coupling coordination index of agricultural eco-economic system increased from 0.268 0 to 0.660 6, besides the coupling coordination state developed from the moderate imbalance level to the primary coordination level. The coupling degree presents a trend from large to small, and the system has experienced a change from depletion development to coordinated development, which indicates the agricultural eco-economic system of Guizhou Province showing a trend of coordinated development. Our results indicate that Guizhou Province should continue to practice the concept of ecological priority and green development, optimize the relationship between ecological environment and economic development and realize the high-level coordinated development of agricultural eco-economic system.