Abstract:[Objective] The impacts of different plant patterns and configuration proportions on soil and water loss of an artificial slope were analyzed in order to provide reference for artificial slope vegetation restoration.[Methods] Natural rainfall from January to December 2019 was measured and the runoff and sediment yield characteristics for runoff plots was simulated using four different vegetation patterns to determine the runoff and sediment reduction benefits of different vegetation patterns.[Results] ① Total rainfall during the observation period was 1 053 mm, and total rainfall duration was 845.1 hours. Rainfall in July was the largest, and rainfall in February had the longest duration. Rainfall was concentrated in January to July, and classified mainly as moderate rain, heavy rain, and rainstorm. ② The variation in runoff yield per rainfall was large, and the variation in monthly and seasonal runoff yield was also large, mainly occurring in February-April and July, in events classified as moderate, heavy rain, and rainstorm. ③ The sediment yield of field rainfall, monthly rainfall and seasonal rainfall was very different. Sediment yield in March was the highest, and the sediment yield was concentrated in February-April and July, with frequent occurrences of moderate rain, heavy rain, and rainstorm events. ④ Compared with the flower-grass pattern, the shrub-grass pattern had the largest runoff reduction and the tree-grass pattern had the largest sediment reduction rate under each rainfall type. The tree-grass pattern had the largest sediment reduction rate, and the herb pattern had the largest runoff reduction rate under the monthly rainfall accumulation. The tree-grass pattern had the largest runoff and sediment reduction rate under the condition of accumulation of different rainfall classes and annual accumulation.[Conclusion] In the early stage of vegetation restoration, affected by the difference in vegetation coverage, the tree-grass pattern and the herb pattern had a higher rate of flow reduction and sediment reduction, and had better soil conservation benefits.

Abstract:[Objective] The water conservation function of litters of artificial Pinus tabuliformis forests in the Ziwuling forest region of the Loess Plateau was determined in order to provide a theoretical basis for function-oriented stand improvement.[Methods] In August 2021, artificial Pinus tabuliformis forests with six stand densities (2 222, 3 200, 4 802, 6 250, 7 503, 9 286 plants/hm²) were selected in the Lianjiabian Forest Farm in Ziwuling, Heshui County, Gansu Province. The coordinate comprehensive evaluation method was used to evaluate the water conservation function of P. tabuliformis forests.[Results] ① The thickness and volume of litters ranged from 2.78 to 7.30 cm and from 14.97 to 52.41 t/hm², respectively. With the increase of stand density, the thickness and volume of litters showed a "single peak" change, with the peak appeared at 4 802 plants/hm². ② The maximum water-holding rate (192.98%) and effective interception rate (152.04%) of litter for the 3 200 plants/hm² stand were higher, while the maximum water-holding capacity (101.46 t/hm²) and effective interception amount (67.92 t/hm²) of litter for the 4 802 plants/hm² stand were excellent. The semi-decomposed layer played a major role in the precipitation interception process of litters. ③ The water-holding rate/amount, water absorption rate, and soaking time of litters showed logarithmic responses (R²>0.956, 0.962) and a power function response (R²>0.998), respectively. ④ The water conservation function of litters was better when the density of the P. tabuliformis forest was 4 802 plants/hm².[Conclusion] When only considering the water conservation function of litters of an artificial P. tabuliformis forest, the density of the forest should be 4 800 plants/hm². In the future, research on the canopy and soil layer of the P. tabuliformis forest should be strengthened. The soil moisture vegetation bearing capacity and the water utilization law of the forest should be comprehensively considered to determine the stand density of the forest that provides the best water conservation function.

Abstract:[Objective] The distribution characteristics of soil nutrients and soil moisture content (SMC) in the Qilian Mountains were explored in order to provide references for soil and water conservation and ecological vegetation restoration in this area.[Methods] Four alpine vegetation types (alpine meadow, alpine shrub, temperate steppe, and temperate desert) were studied. The distribution characteristics of soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), and SMC at different soil depths and four slope directions under the four vegetation types were analyzed through field investigation, laboratory experiments, and mathematical statistics, and their correlations with air temperature and annual cumulative rainfall were analyzed.[Results] ① SOM in the study area was 1.85~190.31 mg/g; TN was 0.07~7.99 mg/g; TP was 0.24~1.81 mg/g; and SMC was 0.79%~3.21%. ② The differences in SOM, TN, TP, and SMC content were mainly affected by differences in vegetation types. Soil moisture content of different vegetation types followed the order of alpine meadow > alpine shrub > temperate grassland > temperate desert. TN followed the order of alpine shrub > alpine meadow > temperate grassland > temperate desert. TP contents followed the order of temperate grassland > alpine meadow > alpine shrub > temperate desert. Regarding the four slope directions, TP content was the highest on the semi-shady slope and the lowest on the sunny slope. The contents of SOM, TN, and SMC were the highest on the semi-sunny slope. ③ SOM, TN, TP, and SMC were significantly positively correlated with annual cumulative rainfall (p<0.01). SOM and SMC were significantly negatively correlated with annual average temperature (p<0.01). TN was significantly negatively correlated with annual average temperature (p<0.05).[Conclusion] The implementation of soil and water conservation and ecological vegetation restoration measures in the Qilian Mountains can be considered for semi-sunny slope, alpine meadow areas. For alpine shrub and meadow areas, the beneficial cycle of ecosystem materials appropriate to local conditions should be promoted.

Abstract:[Objective] Estimation of the eco-environmental water demand of the Qingshui River channel was carried out in order to provide a basis for ensuring normal ecological functioning and rational allocation of water resources in the basin.[Methods] The eco-environmental water demand of different sections of the main stream of the Qingshui River channel was calculated based on water consumption and an analysis of multi-year hydrological statistics. The seasonal variation characteristics of runoff along with precipitation time and the multi-year hydrological characteristics were considered in the context of ecological water security. With respect to the requirements of different ecological functions of rivers, the Tennant method, area quota method and 90% guarantee rate minimum monthly water demand method were used to calculate the basic ecological water demand, evaporation water demand, sediment transport water demand, and water self-purification water demand.[Results] The eco-environmental water demand of the Qingshui River channel included basic ecological water demand, evaporation water demand, sediment transport water demand, and self-purification water demand. The total annual water demand was 6.29×10⁶ m³ for the upper reaches of the river, 6.57×10⁷ m³ for the middle reaches, and 1.65×10⁸ m³ for the lower reaches.[Conclusion] The eco-environmental water demand of the Qingshui River channel was directly related to sediment content and water quality, and high sediment content was the main factor for the high eco-environmental water demand of Qingshui River channel.

Abstract:[Objective] The potential of check dams to retain silt and utilize water resources were analyzed in order to provide a basis for water resource utilization and management of check dams.[Methods] The current construction status, the quantity and spatial distribution of sediment retention, the utilization benefit, and the potential of water resources for check dams in sandy and coarse sand areas of Gansu Province were analyzed by investigation.[Results] By the end of 2019, 1 600 check dams had been built in Gansu Province, including 559 large dams, 452 medium dams, and 589 small dams. These dams controlled an area of 4 101 km², with a total capacity of 481.95 million m³, of which the designed siltation capacity was 229.08 million m³. The current soil interception capacity of these dams was 142.87 million m³, accounting for 62.37% of the designed interception capacity. The interception amounts of large, medium, and small dams accounted for 80.86%, 13.21% and 5.93%, respectively, of the total interception by check dams. The Jinghe River basin, the main channel of the Yellow River, the Liujiaxia Reservoir area, the Weihe River basin, and the Taohe River basin accounted for 71.46%, 13.91%, 12.72%, 1.91%, respectively of the total interception. Due to a decrease in the soil erosion modulus, the actual mean interception capacity of large dams accounted for 43.88% of their designed capacity after 17 years of siltation (the average designed siltation period was 15 years). The actual mean interception capacity of medium-sized dams accounted for 38.81% of their designed capacity after 13 years of siltation (the average designed siltation period was 10 years). The remaining storage capacity of the check dams in Gansu Province was 86.21 million m³ that can be used to store water for utilization. Currently, water in check dams is mainly used for drought emergencies, efficient water-saving irrigation of farmland and orchards, diversified land management, comprehensive economic development, livestock and poultry breeding, and comprehensive development and utilization of water. In the future, 147 check dams can be used to reserve water for human drinking, irrigation, and aquaculture (fish ponds) in Qingyang, Pingliang, Tianshui, and Anding of Dingxi.[Conclusion] In order to meet the social demand for check dams in the local rural revitalization and high-quality development strategy, for areas with water storage and water needs, the design standards of new dams should be improved, and high-standard check dams that can store water for a long time should be built. The large and medium-sized check dams that have been built will be upgraded reconstruction to ensure the safety of the check dam body, flood control and water resources utilization. More importantly, it is necessary to establish an early warning mechanism for the risk management and control of check dams to effectively resolve the contradiction between water storage and flood control management in check dams in water-deficient areas.

Abstract:[Objective] The effects of natural rainfall on soil erosion characteristics of sloping lateritic soil was analyzed in order to provide a theoretical basis for the comprehensive management of soil and water conservation in a lateritic soil area.[Methods] Based on in-situ observations from runoff plots, runoff amounts and sediment yields under erosive rainfall events from May to October 2020 for sloping farmland (cropped to sugarcane), abandoned land, and bare land in the Guangxi Zhuang Autonomous Region were analyzed, and combined with rainfall characteristics to determine the effects of rainfall characteristics and distribution on soil erosion characteristics of sloping soil.[Results] ① During the observation period, runoff amounts and sediment yields under different treatments followed the order of bare land>sugarcane land>abandoned land. Runoff amounts and sediment yields under all treatments were concentrated in August. Monthly differences for runoff amounts and sediment yields in abandoned land were relatively small. ② Runoff amounts and sediment yields were significantly related to rainfall amounts for all treatments. Only rainfall duration had significant positive correlations to runoff amounts for sugarcane land and abandoned land. Moderate rain and heavy rain accounted for 70.9% of the total erosive rainfall amounts. For the sugarcane land, bare land, and abandoned land treatments, the main sources of runoff were moderate rain and heavy rain, which accounted for 68.2%, 78.6%, and 67.8%, respectively, of the total runoff. Erosion was mainly caused by heavy rain, accounting for 63.8%~83.4% of the total amount of erosion.[Conclusion] For a lateritic red soil slope in the Guangxi Zhuang Autonomous Region, sugarcane land and abandoned land effectively reduced runoff and sediment yield on the slope more than bare land, and the reduction effect was more significant for abandoned land. Rainfall amount was the most important rainfall characteristic affecting runoff and sediment yields. Moderate rain and heavy rain were the mainly sources of runoff sediment yields. The distribution characteristics of runoff and erosion on slopes were influenced by rainfall distribution and rainfall frequency.

Abstract:[Objective] The effects of plant density regulation on soil physical properties and plant diversity of different plant stands in the Yellow River flood plain were analyzed in order to provide a theoretical basis for optimizing stand growth, improving soil physical properties, and increasing understory vegetation diversity.[Methods] Three plantations (Fraxinus chinensis, Salix matsudana, Ulmus pumila) growing under the same site conditions in the Wangzhuang Forest Farm, Lijin County, Dongying City, Shandong Province were selected as the research objects. The soil bulk density, porosity, water-holding capacity, and vegetation growth of different stand densities (3 m×3 m, 3 m×6 m) were investigated.[Results] ① Reducing stand density to 3 m×6 m increased crown width, diameter at breast height, and tree height of each stand, as well as the biomass and diversity of understory plants. The increase of each stand factor index in the U. pumila plantation was significantly greater than observed for the other stands. ② The stand density of 3 m×6 m reduced the non-capillary porosity of the same soil layer, and increased the capillary porosity and total porosity of the same soil layer. ③ The stand density of 3 m×6 m significantly increased the saturated water-holding capacity and capillary water-holding capacity of the 0-20 cm soil layer in F. chinensis, S. matsudana, and U. pumila plantations (p<0.05), and significantly increased the soil moisture content of the 20-40 cm soil layer in the U. pumila plantation (p<0.05).[Conclusion] Decreasing stand density resulted in a significant increase in biomass and diversity of understory plants in the U. pumila plantation, and soil capillary porosity and total porosity in the F. chinensis plantation were also increased significantly. Decreasing stand density also significantly increased soil saturated water-holding capacity and capillary water-holding capacity in the 0-20 cm soil layer of F. mandshurica, U. pumila, and S. matsudana plantations, and soil water content in the 20-40 cm soil layer of the U. pumila plantation was also significantly increased.

Abstract:[Objective] The development characteristics of preferential flow for a vetiver slope and the relationship between vetiver roots and preferential flow were analyzed in order to provide a theoretical basis for further study on the influence of plant roots on slope soil stability under varying rainfall conditions.[Methods] Preferential flow on a vetiver slope was studied by using a dye tracer test with simulated rainfall amounts of 30 mm and 50 mm, and plant spacings of 50 cm and 10 cm.[Results] The hydraulic response of the slope soil was greatly increased when vetiver plant spacing was reduced from 50 cm to 10 cm. Under the action of 50 mm of rainfall, the dyeing area ratio and preferential flow ratio for the 10 cm plant spacing were 1.55 and 1.76 times of those for the 50 cm plant spacing, respectively. There was no obvious change in the number of dyeing paths within the topsoil depth range of 0-10 cm. In the topsoil depth range of 10-35 cm, the number of dyeing paths with the 10 cm plant spacing was more than that of the vetiver slope soil with the 50 cm plant spacing. When rainfall was increased from 30 mm to 50 mm, the water flow migrated more quickly into the sloped soil through the dominant channel. The dyeing area ratio (36.11%) and preferential flow ratio (67.25%) with 30 mm rainfall was less than the dyeing area ratio (49.68%) and preferential flow ratio (79.96%) with 50 mm rainfall. The number of dyed paths increased with increasing rainfall.[Conclusion] The root characteristics of vetiver were closely related to preferential flow. When selecting plant slope protection, reasonable plant spacing should be selected to maximize the mechanical and hydrological effects of root slope protection.

Abstract:[Objective] The temporal and spatial change characteristics of a soil conservation function in Southern Jiangxi Province were analyzed in order to provide a scientific basis for improving soil conservation capacity and maintaining an ecological security barrier in southern hills.[Methods] The InVEST model was used to calculate the soil retention capacity of different land use types, different elevations, different slopes, and different counties in Sourthern Jiangxi Province using data observed during 2000, 2010, and 2018. The spatial correlations between soil conservation capacity and NDVI, and the temporal and spatial characteristics of soil conservation functions in Sourthern Jiangxi Province were analyzed.[Results] ① The areas of cultivated land, irrigated forest land, water, and unused land decreased, while the areas of urban land and rural residential land increased. ② The value of soil retention capacity increased from 189.93 t/(hm²·yr) to 190.50 t/(hm²·yr), and the peak values were observed in forest land, which increased from 259.85 t/(hm²·yr) to 262.03 t/(hm²·yr). ③ The value of soil retention capacity in the boundary region was higher than in the central region. The value increased first and then decreased with increasing altitude, and increased with increasing slope. ④ Soil retention capacity and NDVI were positively correlated (p<0.01). The high-high agglomeration areas were located in the northern, western, and southern regions; the high-low agglomeration area was located in the central region (including Yudu County); and the low-low agglomeration area was located in Zhanggong County, Gan County, and Nankang County.[Conclusion] Soil retention capacity in the Gannan region was highly associated with land use type, elevation, slope, NDVI, and economic development level. To improve the value of soil retention capacity, soil protection measures in low-altitude and low-slope areas should be increased. Additionally, improving soil retention capacity in the middle and low mountainous areas by increasing the spatial variation of land use types in the low and middle mountain areas would reduce soil erosion and ecological risk in mountainous areas.

Abstract:[Objective] The temporal and spatial characteristics of desertification risk were analyzed for the Bortala Mongolian Autonomous Prefecture in order to provide a scientific basis and data support for ecological restoration, including formulation of sand prevention and control measures.[Methods] A desertification risk evaluation index system that included nine natural and socio-economic indicators was constructed by using ENVI and ArcGIS software to evaluate the risk of desertification. The characteristics of temporal and spatial changes were analyzed for the Bortala Mongolian Autonomous Prefecture from 2000 to 2020.[Results] ① The risk of desertification showed strong spatial heterogeneity in the Bortala Mongolian Autonomous Prefecture during 2000-2020. The extremely high risk and high risk areas were concentrated in Jinghe County and Alashankou City, located in the east of the Bortala Mongolian Autonomous Prefecture. The moderate risk and low risk areas were located in Bole City and Wenquan County in the central part of the Bortala Mongolian Autonomous Prefecture. The moderate risk level constituted the largest proportion of the total area (more than 40%). ② From 2000 to 2020, the risk of desertification shifted from extremely high risk to high risk, from high risk to moderate risk, and from moderate risk to low risk, showing a declining trend in risk of desertification. The extremely high risk area decreased by 3 160.3 km², and the low risk area increased by 2 424.76 km² by 2020. ③ From 2000 to 2020, the extremely high risk and the high risk centers of desertification moved eastward. The shift of the extremely high risk center was the most obvious, gradually moving to the east of Jinghe County. The medium risk and low risk centers did not change significantly, and they were located in Bole City and Wenquan County.[Conclusion] During 2000-2020, the desertification risk level was different in each area of the study area. Therefore, in order to prevent and control desertification, ecological restoration projects should be carried out reasonably and effectively according to local conditions.

Abstract:[Objective] The spatio-temporal variations of a typical herbicide (atrazine, ATR) and its degradation products[deethylatrazine (DEA) and deisopropylatrazine (DIA)] during the crop growing season (June to September) was investigated in order to provide scientific supports for management, usage, and protection of herbicides in a small agricultural watershed.[Methods] Eighteen sampling sites were designated along the Baima River, and the spatio-temporal dynamics of pollutants were obtained through the combined methods of field monitoring and lab analysis. Ecological risk was evaluated by the risk of herbicides quotient method.[Results] ① ATR and its metabolites were detected in all of the collected water samples. ATR detection rates in surface water samples in June and July were higher than those in August and September. However, the detection rates of metabolites including DEA and DIA were low in the first two months and increased in the later two months. ② The spatial distribution of herbicide pollution in the Baima River showed that the maximum values of pollutants mainly occurred in the upper and middle reaches of the river. The concentration levels in the lower reaches were relatively low, which may be attributed to the wide river channel, large water flow, and strong dilution effect in the lower reaches of the river. ③ The risk levels of ATR, DEA, and DIA for the entire river were all at the moderate level due to low water load and insufficient dilution capacity of the river.[Conclusion] Compared with larger watersheds, the Baima River, as a small tributary of typical agricultural watersheds, has small water volume and insufficient dilution capacity that results in higher ecological pollution risks than many larger basins.

Abstract:[Objective] The soil erosion status and the relationships between soil erosion intensity and different slope and land use types in a small watershed of an intensive sugarcane-growing area with a typical lateritic soil were investigated in order to provide a theoretical reference for soil erosion control in this area of the Guangxi Zhuang Autonomous Region.[Methods] With the support of GIS spatial analysis technology, the revised universal soil loss equation (RUSLE) was used to quantitatively estimate soil loss.[Results] ① The Nala watershed slope ranged between 0° and 35°, and the slope farmland (sugarcane) and forest land (eucalyptus) accounted for 82.85% and 10.99%, respectively, of the total land use area, while roads and channels accounted for 6.16%. The average soil erosion rate of the Nala watershed in 2020 was 22.97 t/(ha·yr) (classified as mild erosion), and this rate was 4.6 times of the allowable soil loss rate of 5 t/(ha·yr) stipulated by the ministry of Water Resources for the southern red soil hilly region. ② Soil erosion mainly occurred on slopes ranging from 5° to 25°, and areas with slopes in this range were the key areas to target for the prevention and control of soil erosion. ③ Among different land use types, the average erosion rate of forest land (eucalyptus) was 53.59 t/(ha·yr), which was 2.84, 2.12, and 27.91 times of the erosion rate of slope farmland (sugarcane), roads, and channels, respectively.[Conclusion] The RUSLE model can be used to estimate soil erosion and soil erosion intensity distribution characteristics of different slopes and land use types in sugarcane-growing areas by inputting relevant parameters and processing data with software. Land use types such as slope farmland (sugarcane), forest land (eucalyptus), and roads should be properly planned and managed so as to take targeted and effective soil and water conservation measures.

Abstract:[Objective] The distribution and dynamic characteristics of soil and water loss at Wuding River, a typical coarse sediment tributary in the middle reaches of the Yellow River, were analyzed in order to provide a scientific basis for soil and water conservation, ecological environment construction, and high-quality development of the basin in the new period.[Methods] Based on the results of three censuses (1985, 1999, and 2011) and national dynamic monitoring of soil and water loss in 2019, the intensity and area of annual soil and water loss at Wuding River basin were extracted, and the spatial and temporal distribution and dynamic change characteristics were analyzed. The variation characteristics of water and sediment in the basin from 1980 to 2018 were analyzed by the Mann-Kendall test based on hydrologic data.[Results] The soil and water loss area in the basin in 2019 was 1.20×10⁴ km², which was dominated by hydraulic erosion. Wind erosion was mainly observed in the sandstorm area in the northern part of the basin. The sediment transport modulus of the downstream main stream (Baijiachuan-Suide + Dingjiagou section) and the Xiaoheihe River above the Suide was more than three times higher than the average higher than level of the basin, and was the main source of sediment. Compared with 1985, the soil and water loss area decreased by 1.40×10⁴ km², with a decrease rate of 53.87%. Sediment discharge and runoff showed decreasing trends, and the inflection points appeared in 2007 and 1996, respectively. The spatial distribution of wind erosion was changed from concentrated and contiguous in 1985 to scattered in 2019. The intensity of hydraulic erosion was reduced from Zhaoshiyao to the outlet section of the left bank of the main stream.[Conclusion] Soil and water conservation has effectively curbed soil erosion at Wuding River basin, but soil and water loss is still serious. In the future, it is necessary to strengthen the comprehensive control of soil and water loss by combining research results with work experiences obtained from historical soil and water conservation efforts.

Abstract:[Objective] An urban ecological security system with relatively complete regional environmental characteristics and social development level for Beijing City was constructed in order to provide a scientific reference for effectively controlling the ecological security bottom line for urban expansion and development, and thereby protect urban biodiversity.[Methods] The ecological sources for Beijing City were extracted based on water conservation, biodiversity maintenance, wind and sand fixation, soil and water conservation, and various nature reserves in the city. A multi-factor index that considered the whole domain by using a minimum cumulative resistance (MCR) difference model (namely the ecological source expansion resistance and surface resistance difference) was used to divide the national urban sprawl spatial pattern of ecological land, such as high level ecological area, medium level ecological area, low level ecological area, ecological town critical area, low level urban construction area, medium level urban construction area, and high level urban construction area. The ecological corridor and ecological node area were identified in order to construct a land security pattern for Beijing City.[Results] The total area of ecological sources in Beijing City was 3 568.95 km², accounting for 21.7% of the total land area of the entire region, which was concentrated in the northwest part of Beijing City and surrounded the central and western urban areas. There were 11 important ecological corridors and 153 ecological nodes, of which Shijingshan District had the largest ecological network density and Dongcheng District had the smallest ecological network density. The construction area in the center of Beijing City was spreading in the pattern of a "spreading big cake", and the degree of rupture of ecological corridors in the city was high.[Conclusion] The ecological pattern of Beijing City is obviously fragmented. In the future, the spatial layout of ecological nodes should be optimized to obtain ecological benefits by protecting ecological sources, planning ecological corridors, and controlling the construction of critical areas of ecological towns.

Abstract:[Objective] The relationship between ecological spatial network structure and soil conservation was analyzed in order to provide countermeasures and suggestions for improving ecosystem services in the Loess Plateau barrier region.[Methods] Based on the importance of ecosystem services, ecological sensitivity, and landscape stability, the ecological source area was identified, an ecological space network was constructed, and the relationship between the ecological space network topology and the amount of soil conservation was analyzed.[Results] ① Water conservation was high in the Qinling Mountains in Southwest China. The districts and counties on the west side of the Luliang Mountain Range-Huanglong Mountain, and the west side of the Ziwuling Mountains had low soil conservation. The Qinling Mountains and the east side of the main ridge of the Ziwuling Mountains had high biodiversity. The ecological environment in the western region was more sensitive, and the overall landscape pattern of the region was relatively stable. ② The total area of ecological source area was 46 245 km², accounting for 38.8% of the entire area. There were 125 ecological corridors with a total length of 9 071.40 km. ③ There were a total of 142 ecological nodes, and the degree of the source node was positively correlated with the amount of soil conservation.[Conclusion] The ecological space network based on "importance-sensitivity-landscape characteristics" was accurate and feasible. The construction of weak nodes and source nodes with low degree values should be strengthened so that the soil conservation services of ecological land can exert greater ecological benefits.

Abstract:[Objective] The effects of cultivated land fragmentation was evaluated and predicted in order to provide a useful reference to address the problem of cultivated land fragmentation in the Jizhou District of Tianjin City.[Methods] The temporal and spatial evolution characteristics of cultivated land fragmentation from 2000 to 2020 were analyzed by means of evaluation index system construction and factor analysis weighting. The CA-Markov model was used to evaluate the predicted land use pattern in 2025 for cultivated land fragmentation, and to perform spatial autocorrelation analysis of the evaluation results in order to judge the spatial distribution characteristics of cultivated land fragmentation level.[Results] ① Cultivated land fragmentation increased from 2000 to 2005 from the southern plain to the northern mountainous area. ② From 2005 to 2020, the deepening degree of fragmentation in the south was more obvious than in the north. ③ Cultivated land fragmentation of 18 towns in the Jizhou District will decrease to varying degrees by 2025, but the degree of cultivated land fragmentation in the north will still be more severe than in the south. ④ Cultivated land fragmentation from 2000 to 2025 in towns and villages in southwestern Jizhou will maintain the characteristics of low-low agglomeration, and occasionally the high-low agglomeration phenomenon will appear. Except for the characteristics of low-high agglomeration in 2020, the towns and villages around Yuqiao reservoir will show spatial distribution characteristics of high-high agglomeration in other years.[Conclusion] The temporal and spatial evolution characteristics of cultivated land fragmentation were obvious, and the quantitative results of fragmentation were clustered. Based on the above analysis results, improvement measures for north-south division and key guidance recommendations are proposed.

Abstract:[Objective] The spatio-temporal pattern and interrelationship between the value of ecosystem services and ecological risks in river basins were analyzed in order to ensure healthy and sustainable development of ecosystems, maintain regional ecosystem balance, and promote the coordinated development of human-land relationships. The results will provide a scientific reference for policy formulation for the comprehensive management of the Huaihe River basin.[Methods] Based on land use data and socio-economic statistical data for the Huaihe River basin in Anhui Province from 2000 to 2019, a dynamic evaluation model of ecosystem service value was established by using the dynamic equivalence method. The ecosystem service value of the study area was calculated for each year. Combined with spatial exploratory data analysis, the heterogeneity and correlation of the spatial and temporal evolution processes of the ecosystem service value (ESV) and ecological risk (ER) were discussed.[Results] ①Conversion of land types in the research area from 2000 to 2019 occurred frequently, with the greatest transfers occurring for construction land and farmland (1 488, 1 763 km², respectively). ② The total amount of ESV exhibited a fluctuating upward trend, from 3.13×10¹⁰ yuan to 3.58×10¹⁰ yuan. The ecosystem services were mainly regulatory services. Farmland and water contributed more than 70% to the total ESV. The high value ESV area was located mainly in Liu'an City and on both sides of the Huaihe River tributaries. ③ The ER index was stable overall. The average fluctuation of ER in the study area was within the range of 0.01. The spatial distribution showed the characteristics of high in the central part of the region and low in the southwest. The high value ER area was mainly located around urban construction land.[Conclusion] The total number of ESVs in the study area exhibited a dynamic upward trend. ESV and ER exhibited spatial aggregation in the study area, and there were positive spatial association characteristics.

Abstract:[Objective] The spatio-temporal distribution and variation characteristics of soil erosion in the Huangshui River basin in the upstream region of the Yellow River were analyzed in order to provide basic data and a basis for decision-making in relation to soil and water conservation and erosion prevention.[Methods] Based on MODIS and Landsat images, precipitation, population density, and the economy in 2000 and 2018, we used low altitude UAV remote sensing, the RUSLE model, and geostatistics to calculate, validate, and analyze the spatio-temporal variability of a soil erosion model in the Huangshui River basin.[Results] ① The average soil erosion modulus of Huangshui River basin in 2000 was 477.81 t/(km²·yr), and the percentage of the area with slight erosion was 72.06%. The percentage of area with moderate, strong, and severe erosion was 3.46%. Mild and moderate erosion areas were mainly located in the mountains and wastelands in the Northern Qilian Mountains, the Central Daban Mountains, and the Southern Laji Mountains, with high altitude and low vegetation coverage. ② In 2018, the average soil erosion modulus of the Huangshui River basin was 1 625.30 t/(km²·yr). The percentage of area with mild erosion was 55.38%, and the percentage of area with moderate, strong, and severe erosion was 21.26%. The area of moderate erosion was mainly located in the urban agglomeration area and where river beaches were located in the southeast part of the study area. The strong erosion and extra-strong erosion areas were sporadically distributed in bare areas in the Qilian Mountains and the Daban Mountains. ③ From 2000 to 2018, the area of slight erosion decreased by 16.68%, the area of moderate erosion increased by 8.15%, the area of strong erosion increased by 5.60%, and the area of severe erosion increased by 4.05%. The region with increasing erosion was mainly located in the bare mountains and urban areas.[Conclusion] Low-altitude UAV remote sensing technology can effectively validate the calculation results of the regional soil erosion model. Soil erosion in the Huangshui River basin has be accelerated over time, and showed great spatial differences. The spatial pattern of soil erosion intensity has evolved from mild, slight to moderate in the Qilian Mountains and the Daban Mountains. This evolution tendency is related to the warmer-wetter climate and intensified human activity.

Abstract:[Objective] The water quality of Bohai Sea was monitored from 2015 to 2020, and the correlation between the change of ecological environment in the coastal waters of the Yellow River estuary and sediment and runoff into the sea was analyzed, in order to provide a basis for the ecological environment protection in the Yellow River estuary.[Methods] The water quality pollution index and biodiversity index evaluation method were used to analyze and evaluate the Pearson correlation coefficients between marine biodiversity and each monitoring index of seawater using SPSS software.[Results] The main pollutant exceeding the standard in the coastal waters of the Yellow River estuary was inorganic nitrogen, and its single pollution index fluctuated from 0.63 to 1.40, which exceeded the second-class water quality standard. The concentration of inorganic nitrogen was positively correlated with the sediment transport from the Yellow River to the sea, and the correlation coefficient was 0.833 (p<0.01). During the summer survey, 77 species of phytoplankton were collected, mainly located in the northern waters of the Yellow River estuary. Since 2018, the number of phytoplankton species has shown a downward trend, from 67 species in 2015 to 42 species in 2020; 52 species of zooplankton were collected, mainly Located in the offshore waters of the northeast of the estuary, the species of zooplankton have gradually increased since 2015, and the diversity index has risen from the level Ⅳ in 2015 to the level Ⅲ in 2020; 92 species of macrobenthos were collected, mainly located in the east of the estuary In the offshore waters, the species and density of benthic species have increased since 2018. The diversity index has increased from 2.18 in 2018 to 3.01 in 2020.[Conclusion] Since 2015, the water quality in the coastal waters of the Yellow River Estuary meets the water quality requirements for industrial water areas and coastal scenic tourist areas in Sea Water Quality Standard (GB 3097-1997), and the ecological situation has gradually improved. There was a significant positive correlation between the zooplankton diversity index in the coastal waters of the Yellow River estuary and the sediment transport and runoff of the Yellow River, with correlation coefficients of 0.941 (p<0.01) and 0.918 (p<0.01), respectively. There was no significant correlation between phytoplankton and benthic biodiversity indices and sediment runoff.

Abstract:[Objective] The land use conflict in township areas was analyzed from the perspective of "productional-living-ecological" space in order to provide a scientific basis for improving the precision and accuracy of the quantitative and positioning management of land use conflicts, and for exploring integrated and coordinated management paths and strategies.[Methods] Taking Xianyang town, Pucheng County, Nanping City, Fujian Province as the research object, we established an evaluation index system from the aspects of suitability and driving force. We identified the types of land use conflict, and put forward the corresponding conflict management recommendations.[Results] There were 12 types of land use conflicts in Xianyang Town, among which the degree of conflict in high conflict zone and moderate conflict zone was more intense, accounting for 18.00% and 22.41% of the land area respectively.[Conclusion] Land use space conflicts in the study area were large in scope, and high risk. We recommend a strategy of actively developing the competitive advantage area of land use and strictly implementing land use control, and of balancing all kinds of land use conflicts under the premise of protecting ecological land and permanent basic farmland.

Abstract:[Objective] The fuzziness and randomness of highway flood risk indicators, and transform highway flood risk evaluation indicators from qualitative descriptions to quantitative values were analyzed in order to improve highway flood risk prevention and control ability, to provide a scientific basis for decision-making, and to reduce social and economic losses.[Methods] Twelve indicators from three criteria layers (namely, the risk of factors causing disasters, the sensitivity of disaster-pregnant environments, and the exposure of disaster-bearing bodies) were selected to construct a highway flood risk evaluation index system. Then the weight of each index was determined by the AHP-entropy weight method. Finally, a highway flood risk evaluation model was constructed based on an extension cloud model. The flood risk of highways in the central urban area of Chongqing City was divided into risk class Ⅰ to Ⅴ (very low, relatively low, average, relatively high, and very high).[Results] ① 69.62% of highways in the downtown area of Chongqing City had a flood risk of class Ⅰ to Ⅲ, and only 30.38% of highways had a flood risk of class Ⅳ to Ⅴ. Yuzhong District (64%), Banan District (47%), and Jiangbei District (41%) accounted for the highest proportion of high-risk highways, and these region's highways should be targeted for flood prevention and control. ② Yuzhong District (71.06%), Banan District (57.43%), and Jiangbei District (38.76%) had the longest length of high-risk highways, and flood prevention and control measures should be carried out for class Ⅳ and Ⅴ highways in the region.[Conclusion] The "two rivers and four banks" location and the surrounding areas were the most densely populated with high-risk highways, followed by major watersheds, lakes, and reservoirs. The water transportation system of the two rivers and the highway network system in the surrounding areas should be ensured and improved, the construction of hydrological stations and flood-control monitoring and early warning systems in major watersheds should be promoted, and the defense and emergency plans should be prepared.

Abstract:[Objective] The ecological security status of the Gansu section of the main stream of the Weihe River was analyzed in order to provide a theoretical basis for ecological civilization construction of the river basin.[Methods] The DPSIR model was used to construct an ecological security evaluation index system for the Gansu section of the Weihe River. A combined weighting method was used to determine the index weight. An obstacle model was used to diagnose obstacle factors.[Results] ① The ecological safety index of the Gansu section of the main stream of the Weihe River initially decreased and then increased. The level of ecological safety changed from class Ⅳ (more dangerous) to Ⅴ (dangerous) to Ⅳ (more dangerous), and then to Ⅲ (forewarning); ② The project-level index exhibited a small degree of change. Fluctuations in the driving force, pressure, and impact index decreased. Fluctuations in the status and response index increased. The overall ecological security situation improved; ③ Population growth rate, economic growth rate, vegetation coverage rate, urban sewage treatment rate, and agricultural water use efficiency were the main obstacles affecting the ecological security of the Gansu section of the Weihe River.[Conclusion] In the future, greater attention should be focused on the integral unity of economy, politics, culture, and ecological environment, so as to further promote the harmonious development of the economy and ecology.

Abstract:[Objective] The evolution characteristics of land use and landscape patterns from 2000 to 2020 and 2030 at Zhangjiajie City, Hu'nan Province were analyzed in order to propose an optimization strategy for future development of Zhangjiajie City, and to provide references for territorial space planning and eco-tourism development for Zhangjiajie City.[Methods] We analyzed land use change data for Zhangjiajie City from 2000 to 2020 using ArcGIS spatial analysis and Fragstats landscape pattern index. We used GeoSOS-FLUS land use simulation software to predict land use changes and landscape patterns for Zhangjiajie City in 2030.[Results] The land use changes were mainly manifested as a significant decrease in grassland area and a significant increase of construction land from 2000 to 2020. The landscape pattern changed significantly from 2000 to 2020. The overall heterogeneity and fragmentation of the landscape increased first and then decreased, and the shapes of patches tended to be regular. The distribution of landscape types was relatively uniform, and the degree of landscape aggregation degree gradually tended to be stable. In 2030, the land use of Zhangjiajie City was mainly manifested in the concentrated expansion of construction land and the further reduction of grassland. Landscape fragmentation and heterogeneity in Zhangjiajie City showed an increasing trend. The maximum patch area of the dominant landscape increased. The landscape shape became more irregular, and the landscape had a further dispersion trend.[Conclusion] The use of the GeoSOS-FLUS model to simulate future land use had high reliability. In the future, Zhangjiajie City should focus on protecting and optimizing the landscape pattern, and strengthening the management and control of the excellent ecosystem. We recommend the building of a nature reserve system, strengthening the construction of ecological corridors, and improving the integrity of ecosystem and landscape connectivity. We also recommend maintaining the dominant landscape of forest land, optimizing the layout of construction land, reducing the fragmentation of forest land and construction land, and protecting the integrity of the grassland ecosystem.

Abstract:[Objective] The variation characteristics of non-uniformity for the distribution of annual runoff of Chishui River and its response to precipitation was analyzed in order to provide a basis for decision-making regarding the development and utilization of water resources and flood control in the upper and middle reaches of the Chishui River basin.[Methods] We constructed a database for the SWAT model to simulate watershed runoff. The model was calibrated and validated with measured monthly runoff data. Model output data were combined with precipitation/runoff concentration degree (PCD/RCD) and concentration period (PCP/RCP), and the characteristics of annual runoff distribution and its response to precipitation were determined.[Results] The coefficient of determination (R²) and Nash-Sutcliffe efficiency coefficient (Ens) values for two hydrological stations were greater than 0.83 for the calibration period, and greater than 0.69 for the validation period, which meet the accuracy requirements. The annual distributions of precipitation and runoff was significantly uneven, and the change trends for the two were relatively consistent, with precipitation and runoff mainly concentrated in June to August. The temporal and spatial distributions of RCD were significantly affected by PCD. Due to infiltration and evapotranspiration, watershed RCD was usually greater than PCD. But when PCD<0.3, RCD was no longer dominated by PCD. Due to the lag in the response of watershed runoff to precipitation changes, RCP was often greater than PCP, and a small, short-term increase in precipitation had a significant impact on PCP, but a limited effect on RCP.[Conclusion] Precipitation was the leading factor causing changes in RCD and RCP in Chishui River watershed. Changes in the runoff coefficient in different periods were the main reason for the different response characteristics of RCD/RCP compared with PCD/PCP.

Abstract:[Objective] Conducting multi-crop land suitability analysis was carried out in order to provide an accurate and effective method for crop planning, land use planning, and management of agricultural production.[Methods] Based on data mining method, the comprehensive suitability of multi-crop land was quantitatively characterized by a random forest algorithm, a comprehensive index evaluation method, spatially constrained multivariate clustering, and spatial statistics.[Results] ① A random forest algorithm quantitatively and accurately produced the spatial layout of crop planting driven by multi-spatial elements, and identified factors that had a key influence on the selection of suitable planting land for maize and rapeseed. ② The suitable areas for maize and rapeseed planting exhibited significant spatial heterogeneity in the study area. The suitable areas for maize accounted for 91.23% of the total planting land area, but the suitable areas for rapeseed accounted for only 69.64%. The areas suitable for the planting of both crops was 13.08% of the total area, and were mainly located in the central and north parts of Fenggang County, the north part of Meitan County, and the northwest part of Yuqing County.[Conclusion] Data mining provides the possibility of selecting the optimal planting land use pattern. The method used in this study has good potential for evaluating the suitability of land in many locations for the production of various crops.

Abstract:[Objective] The coupling and coordination between water poverty and high-quality economic development was analyzed in order to provide a reference for the efficient use of water resources and high-quality economic development in the Yellow River basin.[Methods] Based on data from nine provinces in the Yellow River basin from 2010 to 2019, The entropy weight method was used with data from nine provinces(or regions) in the Yellow River basin from 2010 to 2019 to determine the water poverty index weight. The coupling coordination degree model and gray correlation degree were used to analyze the coupling coordination degree and mutual influence between water poverty and high-quality economic development in the Yellow River basin.[Results] ① The water poverty index of the provinces in the Yellow River basin generally increased over time, and the level of high-quality economic development was generally low, with obvious regional differences. ② The degree of coupling coordination showed a fluctuating upward trend, with a general spatial distribution pattern of "high in the east and low in the west". ③ The gray correlation coefficients between the indicators of the two systems of water poverty and high-quality economic development were both greater than 0.5, which was in a relatively high level of correlation.[Conclusion] The level of water poverty and the level of high-quality economic development in the Yellow River basin have generally improved over time, and the level of coupling coordination is generally low. Most provinces are in a state of mild imbalance.

Abstract:[Objective] The coordinated development relationship and influencing factors of the two strategic systems of urbanization and rural revitalization in nine Chinese border provinces were analyzed in order to provide a scientific basis for coordinating urban and rural development in border areas and promoting homeland security.[Methods] A comprehensive evaluation system of indicators for urbanization and rural revitalization was constructed, and a coupled coordination degree model and a gray correlation degree model were used to analyze the coupled coordination relationship and influencing factors of two systems in the nine border provinces of China from 2008-2018.[Results] ① The urbanization index of China's border areas from 2008-2018 showed a fluctuating upward trend, and overall land urbanization was higher than population urbanization. ② The overall index of rural revitalization increased from 0.273 in 2008 to 0.756 in 2018. Urban-rural coordination in the border area was vigorously promoted, and the provincial-rural development gap has narrowed over time. ③ The degree of coordination between urbanization and rural revitalization had changed from moderate coordination to high coordination, and the nine border provinces were classified as either optimization and enhancement type, adjustment and progress type, or key breakthrough type according to the degree of coordination of the two systems. ④ The coordinated development of the two systems of urbanization and rural revitalization in the nine border provinces of China was the result of the intertwined and coupled effects of different internal and external forces. Governmental decisions played a key guiding role, interconnection played a "catalyst" role, industrial structure provided an important endogenous "blood-making" role. Government decisions played a key guiding role, connectivity played a "catalyst" role, industrial structure provided an important endogenous "blood" force, and economic development and population migration had an external "blood" role.[Conclusion] The coordinated development of urbanization and rural revitalization in the nine border provinces of China should be promoted by establishing a sound mechanism for urban-rural integration and development, formulating development strategies in terms of zoning and classification, building a new pattern of cross-regional collaborative development, and activating innovation-driven endogenous development momentum.

Abstract:[Objective] The coupling coordination relationship and evolution trend of the agricultural eco-economic system in the loess hilly and gully regions was determined, in order to provide a basis for scientifically evaluating the ecological economic benefits of the region, and for realizing the coordination and sustainable development of agricultural eco-economics.[Methods] Based on agro-ecology and agro-economy data from Wuqi County, Shaanxi Province, an evaluation index system for the agro-ecology and agro-economy system was constructed. The comprehensive evaluation index, coupling coordination state, and coupling degree evolution trends for the agro-ecology and agro-economy systems were analyzed by using the entropy weight method, coupling coordination degree model, and coupling degree model.[Results] From 1990 to 2019, the comprehensive evaluation index of agricultural ecology at Wuqi County initially decreased and then increased. The comprehensive evaluation index of the agricultural economy followed the pattern of relatively rapid rise-stable development-rapid rise. The coupling coordination index increased from 0.29 to 0.63. This increase reflected the coordinated development of agricultural ecology and the agricultural economy in the region that has continuously strengthened over time, and the state of coupling coordination that has evolved from a slight imbalance to a primary level of coordination. The degree of coupling showed a downward trend followed by an upward trend, and the system has transitioned from a depletion development stage to coordinated development, indicating that the agricultural eco-economic system at Wuqi County was constantly developing in a coordinated manner.[Conclusion] We should continue to optimize the industrial structure based on ecological protection and adjust the relationship between ecological and economic development to better coordinate the development of the agricultural ecological environment and the agricultural economy in loess hilly and gully area.

Abstract:[Objective] The water consumption of natural vegetation in the lower reaches of the Tarim River was analyzed in order to provide scientific guidance for ecological restoration.[Methods] Based on Landsat series images and daily meteorological data, the temporal and spatial evolution trend of vegetation water consumption from the Daxihaizi Reservoir to the Alagan section was analyzed by using the improved Penman-Monteith formula method at 30 m spatial resolution.[Results] ① The spatial and temporal distributions of natural vegetation water consumption in the research area had obvious gradient differences. The high water consumption area was mainly located along the main river and the natural overflow area. The water consumption of vegetation was generally low in the lower reaches of the Tarim Rive, and it was mainly concentrated during the middle stage of vegetation growth. ② The average water consumption of natural vegetation was 1.90×10⁸ m³/yr and increased at a rate of 2.44×10⁷ m³/5 yr in 2000-2020. During the same period, the river water consumption between the Daxihaizi Reservoir and the Alagan section was 2.79×10⁸ m³/yr. Vegetation water consumption accounted for 68.23% of the river water consumption, and both increased with the water conveyance process. ③ The natural vegetation area increased at a rate of 12.37%/5 yr, and water consumption increased at a rate of 12.82%/5 yr. The vegetation area matched the growth rate of water consumption. The restoration of natural vegetation responded positively to water conveyance, and continued water conveyance will still promote the rapid restoration of vegetation.[Conclusion] By 2020, after 21 years of ecological water conveyance, the natural vegetation in the lower reaches of the Tarim River has been significantly improved. However, due to the solidification of existing water conveyance methods, water losses by evaporation from the water surface and shallow buried depth areas have increased. The temporal and spatial distribution of ecological water consumption is still feasible and should be optimized.

Abstract:[Objective] Spatial and temporal patterns of intensive urban land use in Guangdong Province were studied in order to promote sustainable and intensive land use to facilitate the goal of ecological civilization construction.[Methods] An index of intensive land use was determined by using the entropy method. Spatial and temporal patterns were then analyzed by kernel density estimation and spatial autocorrelation analysis.[Results] ① In terms of time series, based on the best natural breaking point method, the intensive land use level was divided into four levels:Ⅰ, Ⅱ, Ⅲ, and Ⅳ, respectively, indicating increasing levels of intensive land use during 2012-2019. A definite gap in the level of intensive land use among cities in Guangdong Province was observed, but the gap was narrowing. ② In the spatial aspect, the intensive land use level had the characteristics of agglomeration. The spatial agglomeration situation was respectively low-low, low-high, and high-high type regions. High value areas were mainly located in parts of the Pearl River delta, and low value areas were located in the north of Guangdong Province. ③ The level of intensive urban land use differed over time, but the level of intensive urban land use was improved. In space, the level of intensive urban land use had the characteristics of agglomeration and correlation.[Conclusion] Cities should develop in accordance with local conditions. The Pearl River delta region should continue to optimize its industrial structure, while the Western and Northern Guangdong regions should, with the help of government policies, strengthen inter-regional linkages in order to narrow regional gaps.

Abstract:[Objective] The landscape ecological risk of the Qinling-Daba Mountains was scientifically assessed in order to provide a scientific basis for ecological security construction and for sustainable development in the region.[Methods] The spatial analysis method and the topographic distribution index method were used with land surface cover data for the Qinling-Daba Mountains from 2000 to 2020 to quantitatively analyze the temporal and spatial characteristics of the Qinling-Daba Mountains landscape ecological risk, and its dynamic changes on geographical terrain gradients.[Results] ① The overall ecological risk of the Qinling-Daba Mountains landscape was low, with significant spatial differences. There was an obvious spatial agglomeration effect, presenting a spatial distribution pattern of east and west sides, high in the middle, and low in the north and south. ② From 2000 to 2020, the ecological risk of the Qinling-Daba Mountains landscapes showed a downward trend, with low ecological risk areas expanding significantly, and high ecological risk areas shrinking significantly. ③ High ecological risk values were mostly concentrated in areas with high altitude, complex terrain, or low altitude and flat terrain. Low ecological risk values were predominantly located in areas with medium terrain gradients.[Conclusion] The overall landscape ecological risk in the Qinling-Daba Mountains showed a downward trend, indicating that the quality of the ecological environment in the region had improved. The distribution pattern of landscape ecological risk in the Qinling-Daba Mountains was greatly affected by topography and was relatively stable.

Abstract:[Objective] The productional-living-ecological space conflict was analyzed in order to provide a reference for the management and optimization of land use spatial conflict in small and medium-sized urban agglomerations.[Methods] Land use information was extracted from remote sensing image data for the Xiamen-Zhangzhou-Quanzhou urban agglomeration in 2000, 2010, and 2020. A spatial conflict evaluation index system was constructed to quantify land use conflict from the perspective of landscape ecology, and temporal and spatial evolution characteristics were determined.[Results] ① Ecological production land dominated the Xiamen-Zhangzhou-Quanzhou urban agglomeration, and the area of living and production land increased over time. The increase rate was fastest from 2000 to 2020; ② In general, the Xiamen-Zhangzhou-Quanzhou urban agglomeration exhibited a medium level of spatial conflict during the past 20 years, and spatial conflict had gradually intensified over time. A strong conflict space was evident in the central urban areas and areas surrounding the three major cities; ③ The overall Moran's I index result for land use spatial conflict was highly significant, and the spatial conflict agglomeration effect was enhanced, while the local characteristics of spatial conflict showed obvious high-high agglomeration and low-low spatial agglomeration characteristics. Low-high agglomeration and high-low agglomeration were not obvious, but the internal spatial relationship was basically stable.[Conclusion] The intensity of spatial conflicts has intensified over time. Therefore, people should strengthen regional control and early warning mechanisms of conflict risk.

Abstract:[Objective] The effects of land use transition on ecosystem service values (ESV) in the Wulong District were analyzed in order to provide a basis for decision-making regarding rational land use, optimal allocation of resources, development and protection, and maximization of ESV in the Wuling Mountain region.[Methods] Based on land use data for the Wulong District in 2010, 2015, and 2020, the effects of land use transition on ecosystem service values in the Wulong District were calculated. The spatial-temporal changes of land use transition on ecosystem service values were analyzed by using a land use transfer matrix, a change contribution rate model, and a cross-sensitivity coefficient.[Results] ① In 2020, high values of ESV in the Wulong District were concentrated in Xiannvshan Street and Baima Town in the middle of the Wulong District, while the low-value areas were concentrated on the east and west sides of the Wulong District and Tukan Town in the middle. ② From 2010 to 2020, the ESV in the Wulong District showed an increasing trend; ③ From 2010 to 2020, ESV change and variation contribution rate of different land use types in the Wulong District consistently followed the order of forest>water>cropland>grassland>desert. ④ The sensitivity coefficient of converting grassland to forest land was the highest, while other land use types were not sensitive to the conversion to grassland.[Conclusion] The increase of forest land and water area can greatly increase the total ESV. We suggest increasing the area of garden land and forest land, and strictly controlling the abandonment of cultivated land during the time when adjustments are made to agricultural practices and structure.

Abstract:[Objective] The land use status of the Republic of Rwanda (hereinafter referred to as Rwanda) during 1992-2019 was analyzed in order to provide a reference for land use planning and sustainable use of land resources in Rwanda.[Methods] The spatial and temporal land use change characteristics of Rwanda were analyzed and their key driving factors were determined based on GIS spatial statistical analysis and geographic probes using global land cover data (ESA GlobCover) of European Space Agency from 1992-2019.[Results] ① Rwanda's land use types from 1992-2019 were dominated by agricultural and forest land. The area of urban land increased by 4.5 times, while the area of shrubland and watersheds increased by 0.28% and 2.65%, respectively. The area of agricultural land, forest land, grassland, and wetland decreased by 0.38%, 1.46%, 44.24%, and 0.27% respectively. From 1992-2000 had the largest comprehensive land use movement attitude of 0.19%. The spatial distribution of each land class showed agglomeration. ② The driving effect of each driving factors on each land class varied greatly. The explanatory power of the q-value of each driving factors acting independently was less than the interaction between the two factors.[Conclusion] Socio-economic indicators played a decisive role in land use type changes in the study area over the short term. Therefore, the long-term benefits of land use should be considered in the future to maximise the effective management of land.

Abstract:[Objective] The characteristics of spatial-temporal cultivated land change and its driving forces at county level in Hu'nan Province from 2009 to 2018 were analyzed in order to support the formulation of farmland protection policies.[Methods] The cultivated land dynamic index, landscape indices, and the Geodector model were used to determine the area, spatial distribution, and driving forces of cultivated land changes in Hu'nan Province based on land survey data.[Results] ① The total area of cultivated land increased by 379.02 km² in Hu'nan Province from 2009 to 2018. The newly reclaimed cultivated land was mainly located in the area around Dongting Lake, the Central Hu'nan Basin group, and Northwest Hu'nan Province. ② Due to the implementation of land consolidation projects, the shapes of cultivated land patches became more and more regular over the past ten years. On the other hand, as the mean area of cultivated land patches became smaller and smaller, cultivated land patches in Hu'nan Province showed a significant trend towards fragmentation from 2009 to 2018 that was mainly due to urban-rural development and infrastructure construction. ③ The fiscal revenue and expenditure of local governments, population growth, the output value of agriculture were the main driving forces of cultivated land changes in Hu'nan Province from 2009 to 2018. These driving factors produced a comprehensive impact on the changes of cultivated land through interactions such as dual-factor enhancement and nonlinear enhancement.[Conclusion] The protection of cultivated land in Hu'nan Province has achieved remarkable results in the past 10 years. However, the protection of cultivated land in Hu'nan Province still faces some challenges. Therefore, cultivated land protection in Hu'nan Province during the next decade should give greater attention to the trade-offs between the development and protection of land resources. Development of new cultivated land should focus on reclamation of inefficient construction land in rural areas, rather than on occupying ecological space. Additionally, Hu'nan Province should also optimize policies for the protection and utilization of cultivated land that will promote the productivity of cultivated land so that market factors can play a stabilizing and sustaining role in cultivated land protection.

Abstract:[Objective] The research methods and simulation technology, crucial influencing factors, research focuses, hotspots, and future research directions for rainfall-runoff relationships in China and overseas were analyzed in order to enrich the theoretical basis for the study of land surface hydrological processes and soil erosion mechanisms, and also provide the basis for decision-making regarding regional water resource management practices.[Methods] Based on 828 core journal papers regarding rainfall and runoff in China and abroad during the past 50 years, the CiteSpace visualization software was used for sorting and analyzing the knowledge domain map structure of rainfall-runoff research studies.[Results] ① The study of rainfall-runoff relationships has always focused on the relationship between rainfall, infiltration, surface runoff, and erosion, as well as on the simulation of slope runoff. Research methods have included rainfall simulation, mathematical statistical methods, tracer techniques, etc. In terms of slope runoff simulation, a large number of runoff and confluence models suitable for different environmental conditions have been developed. Although the research methods and simulation techniques have become increasingly advanced, and accurate, follow-up research still needs to be optimized regarding the technical means of simulation testing and the method of applying artificial intelligence (AI) and 3S technology to build a practical regional runoff and confluence coupling model. ② Research studies on the key factors influencing rainfall-runoff relationships, namely surface morphology, rainfall characteristics, and soil properties, have continuously become more in-depth. However, research studies regarding the influence of micro-topographic features and temporal and spatial variations of regional individual rainfall processes on rainfall-runoff relationships, and the comparative studies of surface runoff between different soil types and the same soil types in different natural environments still need to be comprehensively advanced. ③ Most of the domestic research studies have focused on the factors influencing local runoff and confluence under a single soil/vegetation condition through the use of an artificial rainfall simulator. In foreign countries, hydrological models and 3S technology have mostly been combined to study basin scale surface runoff processes, their spatial-temporal variation, and the impact of surface micro-topography. The research scale tends to be comprehensive and in-depth regarding development at both macro-scale and micro-scale. Recently, the research hotspots of rainfall-runoff relationships have focused on karst, runoff plots, forest litter, rainfall characteristics, groundwater recharge, hydrological connectivity, slope, soil physical and chemical properties, water management, etc.[Conclusion] In the future, the advantages of interdisciplinary and technological integration should be further highlighted by strengthening thematic research studies on rainfall-runoff relationships with soil and water conservation, hydrology, and water management in ecologically fragile areas such as karst, arid, and semi-arid areas in order to promote the sustainable utilization of regional water and soil resources and the coordinated development between man and land.

Abstract:[Objective] The temporal and spatial variation characteristics of grassland in the Kherlen River basin were analyzed, and the change laws of grassland in China and Mongolia were compared in order to promote the protection and construction of the local ecological environment and to provide a scientific reference for the sustainable development of cross-border grassland.[Methods] Information was extracted from a series of Landsat images based on object-oriented and random forest classification methods to obtain five-phase land cover data for the Kherlen River basin form 1980 to 2020. Grassland changes and the driving factors of grassland change on both sides of the China-Mongolia border were compared and analyzed by means of a grassland dynamic attitude model, a grassland change transfer matrix and a centroid model.[Results] ① Grassland in the Kherlen River basin declined from 1980 to 2020. A total reduction of 486 km² was found, where grassland on the Chinese side increased by 130 km² (0.88%). The transfer of bare land was the main reason for the increase in the grassland area. The Mongolia side decreased by 616 km² (0.61%), as grassland was mainly converted into bare land and cultivated land. ② The grassland centroid in the Kherlen River basin moved 1.6 km northeast due to the loss of grassland in the middle and lower reaches of the Kherlen River.[Conclusion] The loss of grassland in the Kherlen River basin was the result of the combination of natural and human factors. From the perspective of grassland area transfer, human activity was the direct cause of its grassland loss.

Abstract:[Objective] The research status of watershed ecological compensation was analyzed and mastered in order to provide a basis for improving the compensation system and promoting watershed ecological protection and high-quality development of river basins in China.[Methods] CiteSpace visualization software, Price's law, and the X index were used to analyze 876 studies collected by CNKI for author co-occurrence, high-frequency keywords, and research topic clustering.[Results] Domestic research on watershed ecological compensation mainly began in 2000, and the annual number of publications showed an upward trend. Research hotspots were highly coupled with national policies and watershed development, mainly including quantitative research on watershed ecological compensation standards, research on the behavior of watershed ecological compensation subjects from the perspective of game theory, and research on watershed ecological compensation mechanisms under the background of ecological protection. According to the evolution characteristics of research topics, three stages could be identified:preliminary exploration (before 2007), rapid development (2007-2017), and consolidation and improvement (from 2018 to 2021). During these time periods, research emphasis changed from theoretical analysis to quantitative analysis of compensation standards under the background of water resource governance. The objective of this research focused on the two major water systems of the Yangtze River basin and the Yellow River basin. Researches on the main stream and important tributaries were carried out alternately and gradually deepened. The researches formed multiple basic scientific research platforms, but there were few high-yield authors and little cross sectoral cooperation.[Conclusion] Over the past 20 years, research in the field of watershed ecological compensation in China has formed a certain theoretical system and research framework. The research topics and hot spots have distinctive characteristics, and the research methods have tended to be systematic and diversified. In the future, theory and application should be combined to explore the dynamic and market-oriented compensation mechanisms suitable for regional characteristics.

Abstract:[Objective] The main mechanisms, pathways and characteristics of carbon sinks related to soil and water conservation were explored from the perspective of carbon peak, carbon neutralization goals, and the schedule of Chinese national strategy objectives and goals in order to provide references for comprehensively improving the capacity of soil and water conservation to sequester carbon, and to scientifically promote the high-quality development of comprehensive control of soil and water losses.[Methods] Based on various soil and water conservation measures and their synergistic mechanisms, and referring to relevant research results from home and abroad, the discipline application basis, basic mechanisms, three main pathways, and four kinds of material performance of soil and water conservation related to carbon sinks were systematically discussed and analyzed. Additionally, the main characteristics of soil and water conservation related to carbon sinks were identified.[Results] The role of soil and water conservation related to carbon sinks comes from the joint participation of three types of soil and water conservation measures:plant measures, engineering measures, and farming measures through a variety of pathways that include plants, soil, and water. These measures can reduce CO₂ in the atmosphere and convert it into a variety of carbon compounds for storage in plants and their products, in soil, and in water. The carbon sink pathways related to soil and water conservation include the plant pathway, the soil pathway, and the water pathway. Carbon sinks related to soil and water conservation include biomass, inanimate organic matter, soil organic matter, and water carbon. The main characteristics of soil and water conservation that affect carbon sinks include the joint action of a variety of control measures, the interweaving of a variety of carbon sink pathways, and the locality of carbon sink materials. The characteristics of carbon sinks are obvious over short time periods, and weak carbon sinks are clear over yearly cycles.[Conclusion] Soil and water conservation during this new period of ecological civilization construction should comprehensively promote soil and water conservation as a means of sequestering carbon, implement the monitoring and evaluation of carbon sinks, expand soil and water conservation measures that result in high carbon sinks, construct clean ecological small watersheds, avoid carbon emissions caused by soil erosion and damage control measures, further improve increment in carbon sinks, and consolidate the capacity of carbon sinks.

Abstract:[Objective] The effects of different agroforestry systems on soil physical properties, especially carbon sequestration, in the Yellow River flood plain was determined, in order to provide scientific guidance for optimizing regional agroforestry systems in the future.[Methods] Soil physical properties and carbon sequestration characteristics were analyzed in a Chines ash (Fraxinus chinensis) plantation under different agroforestry systems. Soil samples were collected from an ash plantation located in the Dongming National Forest Farm, Shandong Province, China. The following agroforestry systems were evaluated:ash and chrysanthemum (BJ), ash and peanut (BH), ash and soybean (BD), and ash alone (as the control, CK).[Results] ① The BD system significantly reduced soil bulk density in the 0-20 cm layer (7.4%~13.2% lower than the other systems), with bulk density following the order of CK>BH>BJ>BD. The BD system also increased soil total porosity (2.3%~19.8% higher), improved soil water retention ratio, and improved soil structure; ② The BD system had the strongest soil carbon sequestration capacity (14.54 t/hm² higher than that of CK). Soil carbon sequestration increased with soil depth, and was more conducive to enhancing soil fertility and improving soil quality.[Conclusion] In the carbon neutral mode, the BD agroforestry system should be the focus of agroforestry management in the Yellow River flood plain, because this system not only improves the regional ecological benefit, but also promotes the green development of agriculture and forestry.

Abstract:[Objective] Carbon storage and its spatio-temporal distribution in the Qilian Mountain National Park, and the impact of land use change on terrestrial ecosystem carbon storage were analyzed in order to provide a scientific basis for improving the ecological value of national parks and adjusting ecological engineering and land management policies.[Methods] The land use dynamic index and land use conversion matrix were used to quantitatively analyze land use changes before and after ecological destruction and restoration in the national park. Then, remote sensing image data of land use and carbon density were used as operating data in the carbon module of the InVEST model to calculate the change in carbon storage induced by land use change.[Results] ① The carbon storage values for the Qilian Mountain National Park in 1980, 1990, 2000, 2010, and 2018 were 9.07×10⁸, 9.07×10⁸, 9.07×10⁸, 9.16×10⁸, 9.17×10⁸ t, showing a trend of "decrease first and then increase", with a cumulative increase of 9.86×10⁶ t; ② The spatial distribution of carbon storage was related to land use types. The areas with high carbon storage were mainly located in the east section and east of the middle section of the national park, and corresponded to forest. The areas with low carbon storage were mainly concentrated in the west section and west of the middle section, and corresponded to unused land. ③ Land use changes under the positive ecological evolution that occurred from 1980 to 2018 (i.e., farmland, grassland, and unused land converted to forest; farmland and unused land converted to grassland; and unused land converted to water) were the main reasons for the increase in national park carbon storage.[Conclusion] The positive evolution of ecosystems should be promoted by consolidating ecological engineering, focusing on grassland resource protection, and adjusting land management policies in order to optimize land use structure and to increase terrestrial ecosystem carbon storage for the Qilian Mountain National Park.

Abstract:[Objective] The land-use changes from 2000 to 2020 and in the future (2100) under different development scenarios in the arid region of Northwest China were studied, and the changes in carbon storage and carbon source/sink caused by land-use changes were analyzed, in order to provide a reference for regional land management optimization, carbon sink increase, and environmental protection.[Methods] Based on land use data from 2000 to 2020, the FLUS model was used to simulate the land use situation in 2100. The carbon storage, carbon source/sink, and carbon changes in regional ecosystems in 2000-2020 and in 2100 under different development scenarios were estimated and analyzed by using the carbon submodule of the InVEST model with the revised carbon density and land use data.[Results] ① From 2000 to 2020, the area of cultivated land, grassland, and construction land increased continuously, while the areas of forest land, water, and unused land decreased. The total carbon storage of the region increased by 1.60×10⁸ t during the 21 years, including 2.89×10⁵ t for vegetation and 1.60×10⁸ t for soil. ② Compared with 2020, carbon storage will increase by 6.37×10⁸, 7.78×10⁸ t, and 8.49×10⁸ t, respectively, under the natural development scenario, the cultivated land protection scenario, and the ecological protection scenario in 2100. The carbon storage capacity of the cultivated land protection scenario and the ecological protection scenario will improve significantly, and these will be important ways to increase regional carbon sink. ③ There was obvious heterogeneity in the spatial distribution of carbon storage values in Northwest China. The high-value areas of carbon storage (9 800~14 568 t) were mainly located in mountainous forest areas, while the vast desert and Gobi areas had low carbon storage values (1 600~5 800 t), and the distribution of carbon was closely related to the distribution of regional land use types. ④ From 2000 to 2100, the carbon source/sink area was nested and interlaced. The carbon source area was mainly located over the northern slope of the Tianshan Mountains, the oasis edge of the Tarim Basin, and the Western Kunlun Mountains. The distribution of the carbon sink area was basically consistent with the middle and high value areas of carbon reserves, and concentrated on the mountainous area containing extensive forest land and grassland.[Conclusion] The carbon storage in the arid area of Northwest China showed a continuous upward trend from 2000 to 2020, and the carbon storage in the future under the three scenarios also increased significantly, especially under the ecological protection scenario, which is conducive to the sustainable and benign development of the ecological environment

Abstract:[目的] 探究未来湾区城市群生态空间变化对碳汇的影响，找出变化背后的主要驱动因素，为城市群制定未来生态空间发展方向与策略提供参考，促进陆海新通道的科学开发。[方法] 以北部湾城市群为例，基于2010，2015与2020年土地利用数据，使用GeoSOS-FLUS模型预测生态优先、耕地优先及城镇优先3种不同预设情境下2035年的北部湾城市群生态空间土地利用格局，使用InVEST模型对2020—2035年各情景下生态空间碳汇变化情况进行分析，使用地理加权回归找出影响土地碳汇变化的主要驱动因素。[结果] 生态优先导向下2020—2035年北部湾城市群碳储量有所增加；城镇优先导向下碳储量降低较多，达到3.12×10⁶ t。坡度、人口密度和高程是城市群生态空间碳汇格局最重要的影响因素，城镇空间扩张是变化的主因。生态优先情景下，生态空间的土地将有所增加。[结论] 生态优先导向能兼顾城镇发展与生态空间的环境保护需求，城镇优先导向和农业优先导向会大幅降低碳汇。另外政策措施也需尽早制定以抑制城镇空间扩张。

Abstract:[Objective] The differences in carbon emissions and carbon neutrality due to land use changes were analyzed in order to provide a basis for formulating low-carbon development policies in various regions according to net carbon emissions.[Methods] Based on data for land use and energy consumption in Fujian Province from 2005 to 2020, carbon emissions and carbon neutrality value calculation models were constructed to calculate the carbon emissions and carbon neutrality values for different cities in different periods.[Results] ① The net carbon emissions for land use changes in Fujian Province showed an obvious growth trend, and the growth rate was initially fast and then slowed. Construction land was the main carbon source, and its carbon emissions increased by 34.08 million tons. Forest land was the main carbon sink, and its carbon absorption decreased by nearly 30 000 tons. ② The areas with high net carbon emissions were mainly located in Fuzhou, Quanzhou, and Zhangzhou cities. These areas exhibited high carbon emissions and low carbon neutrality rate. The areas with low net carbon emissions were mainly located in Nanping City where low carbon emissions and high carbon neutrality rate were observed. Except for Xiamen City, the intensity of net carbon emissions in each city was similar to the spatial distribution of net carbon emissions. ③ The carbon neutrality value was highly similar to the spatial distribution of net carbon emissions in each city. The high carbon neutrality areas were mainly in Fuzhou City and Quanzhou City where economic development level was high and net carbon emission was large, while the compensation area was mainly found in Nanping City where economic development level was low and net carbon emission was small.[Conclusion] In order to achieve regional coordination and low-carbon development, it is necessary to constantly improve the carbon neutrality mechanism and to rely on carbon neutrality to promote coordinated development of regional low-carbon policies.

Abstract:[Objective] The relationships between soil carbon and nitrogen in a farmland ecosystem and soil physical and chemical properties were analyzed to provide a theoretical reference for the rational utilization of land resources in an alpine region.[Methods] Nineteen representative farmland sample plots were selected on a southern slope of the middle section of the Qilian Mountains. Total carbon (TC), total nitrogen content (TN), organic carbon content (SOC), and water content (SWC) of soils in the study plots were measured in the laboratory, and soil bulk density (ρ_b), particle size (clay, silt, sand), pH value, and other physical and chemical properties were determined.[Results] ① TC and TN decreased with increasing soil depth, and the average contents of TC and TN were 35.47 g/kg and 2.41 g/kg, respectively. ② The contents of SOC, SWC, clay, and silt also decreased with increasing soil depth, and the contents of soil ρ_b, pH value, and sand increased. ③ Soil physical and chemical properties were related to each other and jointly affected soil carbon and nitrogen content. The direct interaction between soil carbon and nitrogen was significant. Soil ρ_b had a direct effect on soil TC. SWC had an indirect effect on soil TC by affecting soil TN. Soil silt and clay contents had a direct effect on soil TN. Soil pH value had an indirect effect on soil TN by affecting soil silt and clay contents.[Conclusion] Farmland soil on a southern slope of the Qilian Mountains was relatively fertile, and TN and organic matter content were at a high level that could provide sufficient soil nutrients for vegetation growth in the study area. Under the farming practices currently used, the increase in soil TN and SWC was conducive to the accumulation of soil TC content, and the increase of soil TC, clay, and SWC content was conducive to the accumulation of soil TN content.

Abstract:[Objective] The temporal and spatial characteristics and effects of carbon emission changes in the Tacheng area of Xinjiang Uygur Autonomous Region from 1980 to 2020 were analyzed in order to provide the basis for formulating regional carbon emission reduction measures and low carbon regulation policies.[Methods] The spatio-temporal changes of carbon sources, carbon sinks, and carbon emissions based on land use changes from 1980 to 2020 in Tacheng area was analyzed, and the carbon emission effects were evaluated using carbon footprint and ecological carbon carrying capacity.[Results] ① Net carbon emissions in the Tacheng area showed an obvious increase from 1980 to 2020, during which the continuous expansion of cultivated land and construction land area was the main factor leading to the increase in carbon emissions, and the continuous reduction of forest area was the main factor leading to the decrease in carbon absorption; ② In terms of spatial distribution, Shawan County and Wusu City were the main carbon sources, accounting for 67.02% of the total net carbon emissions in the Tacheng area. Hefeng County and Emin County accounted for 20.89% of the total net carbon emissions in the Tacheng area. Tuoli County was the carbon sink in the Tacheng area; ③ For the carbon emission effects, most areas in the Tacheng area showed ecological abundance before 2000, but ecological deficit appeared after 2000.[Conclusion] Shawan County, Wusu City and Hefeng County showed an obvious ecological deficit, and these will be the key control areas for carbon emission reduction in the Tacheng area in the future.

Abstract:[Objective] The spatiotemporal evolution pattern and driving factors of carbon emissions at the county level were determined in order to provide a scientific basis for the practical application of a regional planning strategy that would meet the "dual carbon" goal.[Methods] Based on carbon emission data from the Dongrong development area in the Guangxi Zhuang Autonomous Region in 2005, 2010, 2015, and 2020, spatial autocorrelation analysis was used to calculate the spatio-temporal heterogeneity of carbon emissions among different regions. An index system was constructed, and geographic detectors were used to calculate the driving factors of the spatio-temporal evolution of carbon emissions.[Results] ① There was spatial heterogeneity in carbon emissions among the counties and districts in the Dongrong development area of the Eastern Guangxi Zhuang Autonomous Region. From 2005 to 2020, the carbon emissions in the space were characterized as being "high in the southwest and low in the northeast", and the carbon emissions of the economically developed districts and counties grew rapidly; ② The carbon emissions of the districts and counties showed a steady upward trend in general. The carbon emissions gap between districts and counties with different economic development levels gradually widened; ③ An analysis on the driving forces of spatial and temporal differences of carbon emissions showed that the influence of energy consumption structure and urban economic density was the strongest.[Conclusion] The spatial and temporal characteristics of carbon emissions in the Dongrong development area of the Eastern Guangxi Zhuang Autonomous Region were closely related to human activities. In order to meet the "dual carbon" goal, carbon emissions will need to be regulated.

Abstract:[Objective] The impacts of thermokarst lakes formed by rapid thawing and collapsing of permafrost on soil carbon and microorganisms were studied in order to provide a reference for the study of ecological environment and greenhouse gas emissions in such landform types.[Methods] This paper comprehensively analyzed the research progress of domestic and foreign scholars on the formation and distribution of thermokarst lakes and its effects on soil carbon cycle and microorganisms in recent years using 418 literatures on carbon and microorganisms of thermokarst lakes from 1990 to 2021 in the Web of Science core database.[Results] The main issues currently facing in this field were insufficient identification of small thermokarst lakes, lack of long-term monitoring data of thermokarst lakes, and the need to fully consider the methane cycle process (methane generation and methane oxidation).[Conclusion] In the future, we should use multiple models and additional control variables to assess and predict changes in thermokarst lakes and greenhouse gas emissions, supplement the missing data by high-precision remote sensing images and drone images and a large number of field measurements, and strengthen the study about the effects of the formation and evolution of thermokarst lakes on microbial communities and their ecological functions.