Abstract:[Objective] The ecology of open-pit coal mine areas is fragile and water resources are scarce. Therefore, the use of microorganisms for mine reclamation has become a research hotspot with regard to ecological reconstruction of mining areas. The effects of soil inoculation with arbuscular mycorrhizal fungi (AMF) on maize root growth and water use charateristics under the conditions of a reconstructed soil sponge ecological structure in an open-pit mine dump were determined in order to provide a scientific basis for the implementation of ecological agriculture in mining areas.[Methods] A soil column simulation experiment was conducted in a laboratory. Three treatments were evaluated:a bare soil column (CK), maize without bacterial inoculation (NM), and maize with bacterial inoculation (AM). The stable hydrogen and oxygen isotope tracer technique was used to study water use characteristics by maize roots.[Results] ① The AMF treatment increased maize root growth and changed maize root distribution. Total root length, total root surface area, total root volume, and number of root tips for the AM treatment were 19.3 %, 14.8 %, 9.1 %, and 34.0 %, respectively, higher than observed for the NM treatment. The proportions of fine roots smaller than 0.3 mm and coarse roots larger than 0.7 mm for the AM treatment were 3.2 % and 3.5 %, respectively, higher than for the NM group. ② AMF changed water use characteristics by maize roots by depth. The proportion of water used by maize for the AM treatment from the 0-20 cm soil layer was 5.5 % higher than for the NM treatment. ③ The moisture content of the 0-20 cm soil layer of the AM treatment was significantly lower than for the NM treatment. The moisture content of saturated clay layer of the CK treatment was higher than for the NM treatment, which was higher than for the AM treatment. AMF improved the ability of maize roots to absorb water, and affected the release of water in the clay layer.[Conclusion] AMF inoculation of a reconstructed soil sponge structure in an open-pit mine dump can promote maize root development, improve maize water utilization strategy, and make full use of the water stored in the water layer in the sponge structure.

Abstract:[Objective] The coastal area of the Yellow River is one of the areas experiencing the most severe soil and water loss. The soil moisture and vegetation community characteristics of riparian-sand-fixing forest belt in sandy areas were studied under different zone spacing, and the belt spacing under the optimal allocation mode was determined in order to provide the basis for the construction of row and belt afforestation of riparian sand-fixing forest belt in sandy areas.[Methods] The study was conducted on sand-fixation forest belts with different band spacings at Xiliugou, Dalat Banner, Ordos City, Inner Mongolia. Soil sampling and vegetation surveys were carried out in the sand-fixation forest sample plots with different band spacings of 8 m, 16 m, 22 m, and 28 m. Soil physical properties and vegetation community characteristics were analyzed. The correlation between soil moisture and vegetation was also determined.[Results] ① The soil moisture and vegetation index of different sand-fixation forest belts increased with increasing band spacing. ② The soil moisture for different soil layers in the 0-100 cm soil layer in various zones of the band spacing also increased with the increasing horizontal spacing, and the change tended to be stable after 11 m. ③ Soil moisture in different zones was positively correlated with vegetation index in general, but the evenness index and richness index were different. The greater the band spacing, the better the vegetation restoration effect, and the peak value of the restoration effect was approximately reached when the band spacing was 22 m.[Conclusion] The vegetation restoration effect increased with increasing sand-fixation forest belt band spacing when sandy land was treated with a low coverage row-type sand-fixation forest, but it is not always that the wider the band spacing, the better the vegetation restoration effect. The 22 m band spacing had the best vegetation restoration effect of all of the row-type sand-fixation forest band spacings, and the near-natural restoration effect on sandy land was the best.

Abstract:[Objective] Vegetation restoration can effectively prevent and control soil and water loss on abandoned dreg field of production and construction projects. The runoff and sediment redution effects of various vegetation restoration patterns in an abandoned dreg field were studied to provide a theoretical basis for subsequent management and supervision of the area.[Methods] An artificial rainfall simulation experiment was set up to obtain the runoff and sediment production characteristics of a slope surface covered with selected waste slags under different planting patterns (broadcast sowing, drill sowing and hole sowing) and vegetation restoration stages (growth, maturity and withering periods) from the production and construction projects in the Dabie Mountains of Western Anhui Province, and the patterns and differences were analyzed by methods such as cumulative average deviation.[Results] Compared with bare slope, vegetation restoration effectively delayed the initial runoff generation time. The most obvious effect was observed for broadcast sowing. Various planting patterns exhibited varying degrees of effectiveness in reducing runoff and sediment, with the overall runoff and sediment output from a slope following the order of bare slope > hole sowing > drill sowing > broadcast sowing, and withering period > maturity period > growth period. The production of sediment and runoff were characterized by distinct processes, and the effect of reducing runoff was weaker than that of reducing sediment.[Conclusion] The runoff and sediment reduction benefits of planting methods were shown to be greater for broadcast sowing than for drill sowing, with hole sowing being the worst. The efficacy of reducing runoff and sediment during the growth period surpassed that of the maturity period, while the withering period yielded the least benefits. Among the various sowing patterns, broadcast sowing exhibited the highest efficiency in reducing runoff and sediment during the growth period, with rates of 49.6 % and 95.5 % respectively.

Abstract:[Objective] The relationship between grassland community and functional group quantity changes under grazing disturbance and soil wind erosion in grasslands was analyzed, and the influence of different functional groups on grassland erosion processes were determined to provide a theoretical basis for the rational use and protection of desert grasslands.[Methods] The study was conducted on desert grasslands of Stipa breviflora in Inner Mongolia. A completely randomized experiment was conducted with three grazing treatments:control (CK), moderate grazing (MG), and heavy grazing (HG). Sand transport and functional group characteristics under different treatments were determined.[Results] ① The height, coverage, and aboveground biomass of each functional group generally declined as grazing intensity increased. Appropriate grazing significantly increased the Simpson dominance index and the Shannon-Wiener diversity index. ② Differences in sand transport among different grazing treatments were significant. Sand transport related to different heights followed the order of HG>MG>CK, and sand transport rate decreased significantly as height increased under the same grazing treatment. ③ There was an exponential negative correlation between height, coverage of each functional group, and sand transport, with the height changes of perennial grasses and perennial forbs having a more significant impact on sand transport. Aboveground biomass of each functional group was negatively correlated with sand transport, with the highest fitting degree observed between the biomass of perennial grasses and sand transport.[Conclusion] Overgrazing significantly affected functional group characteristics and reduced the windbreak and sand-fixing capacity of grasslands. Grazing intensity of desert grasslands in Inner Mongolia should be limited to moderate levels or below.

Abstract:[Objective] The soil water characteristics of the mixture of landslide gravel soil and local sedimentary cohesive soil in different proportions in Jiuzhai Valley after the "8·8" earthquake in 2017, were analyzed, and the best improved gravel soil suitable for plant growth in the study area was selected in order to provide scientific basis for ecological environment restoration after earthquake in Jiuzhai Valley region.[Methods] A local clay soil from Jiuzhai Valley and gravel soil from the Jiuzhai Valley region were mixed at different volume ratios, and soil water characteristics were investigated by soil water characteristic curve test, water constant test, and soil column test to investigate the soil water characteristics under the different mixing ratios in order to select soil mixing ratios suitable for plant growth.[Results] ① The van Genuchten model was able to fit the soil-water characteristic curve of the improved gravel soil well, and the soil air-entry value increased as the proportion of clay soil increased. The parameter α characterized the state of the air-entry value to a certain extent. ② The improved gravel soil increased the water absorption coefficient, wilting coefficient, field water-holding capacity and saturated water content as the proportion of clay soil increased. The water availability and maximum effective water volume of the gravel soil increased by 22.26 %~50.00 % with the addition of clay soil (compared with the gravel soil), and the maximum effective water volume similarly increased by 70.96 %~131.46 %. ③ Of the three models evaluated, the Philip model simulated soil water infiltration the best, and the size of the uptake rate (S) can represent the change trend of the initial infiltration rate to a certain extent.[Conclusion] Comprehensive comparisons of the water characteristics of different ratios of improved gravel soil showed that, when the overlying soil layer is a water storage layer, a gravel soil to clay soil ratio of 7:3 can be selected as the optimal ratio for improved gravel soil. When the overlying soil layer is a non-storage layer that is not capable of storing water, a gravel soil to clay soil ratio of 3:7 can be selected as the optimal ratio for improved gravel soil.

Abstract:[Objective] The effects of soil straw hole injection on soil moisture content and crop growth were studied to provide a theoretical basis for increasing rainwater storage capacity and improving water use efficiency in dry farmland.[Methods] A field trial of a maize-wheat rotation was carried out, with four treatments including conventional tillage (CK), and soil straw hole injection of 2 holes/m² (T₁), 4 holes/m² (T₂), and 8 holes/m² (T₃).[Results] All three hole injection treatments increased the surface soil moisture during the entire experimental period. The T₂ and T₃ treatments increased the deep soil moisture content at harvest time, and the moisture content in the 60-80 cm soil layer increased 29.19 % and 28.18 %, respectively, compared with CK at the end of the experiment. Soil straw hole injection treatments increased plant height, yield, biomass, precipitation use efficiency, and water use efficiency. The T₂ and T₃ treatments had the most obvious effect on soil moisture and crop growth, with no significant difference between them.[Conclusion] Water retention and yield were increased by soil straw hole injection treatments. Considering the cost and effects, soil straw hole injection of 4 holes/m² (T₂) is recommended.

Abstract:[Objective] Lingjiang River is an important river basin in Southern Zhejiang Province, which is typical and representative. The hydrochemical characteristics, evolutionary mechanism and irrigation suitability of surface water at Lingjiang River basin were analyzed in order to provide scientific basis for agricultural irrigation, ecological protection and high-quality development in this region.[Methods] Mathematical statistics, Piper three-line graphs, principal component analysis, and ion ratio were used to analyze the hydrochemical statistics and identify the causes of the surface water in the basin. The suitability of surface water for irrigation was evaluated by constructing Wilcox diagrams and USSL diagrams.[Results] ① The hydrochemical types of surface water at Lingjiang River basin were spatially zoned, and the hydrochemical types from HCO₃-Ca type to Cl-Na type transitioned from the middle and upper reaches (zone Ⅰ) to the lower reaches of the Wenhuang Plain (zone Ⅱ) to the estuary of Taizhou Bay (zone Ⅲ). ② The hydrochemical characteristics of the surface water in zone Ⅰ were mainly affected by the dissolution of silicate rock during rock weathering, and were affected to a lesser extent by the dissolution of carbonate karst. The hydrochemical characteristics of surface water in zone Ⅱ were mainly affected by the dissolution of silicate rock. The hydrochemical characteristics of surface water in zone Ⅲ were mainly affected by the dissolution of evaporative salt rocks. ③ The K⁺ and Na⁺ of the surface water in zones Ⅰ and Ⅱ were mainly from the dissolution of silicate minerals. Ca²⁺, Mg²⁺, HCO^-₃, and SO^2-₄ mainly resulted from the dissolution of silicate rock, and a small amount resulted from the dissolution of carbonate rock, NO^-₃ was mainly derived from human activities. ④ The surface water in zones Ⅰ and Ⅱ was suitable for agricultural irrigation, while the surface water in zone Ⅲ was poorly suited for irrigation, and could easily cause saline-alkali damage.[Conclusion] The hydrochemical components of surface water at Lingjiang River basin were affected by natural dissolution and human activities. The surface water in the river network area of the middle and upper reaches and lower reaches of the Wenhuang Plain is suitable for agricultural irrigation, while the surface water in the estuary of Taizhou Bay is prone to saline-alkali damage. Attention should be paid to the planning of agricultural irrigation and ecological protection and high-quality development.

Abstract:[Objective] The effects of Polyacrylamide (PAM) applicated in separation and sediment yield process of sandy soil developed from granite parent material were determined, and the concentration threshold of PAM to increase erosion resistance of sandy soil was clarified to provide a basis for the control of Benggang erosion.[Method] Sandy soil developed from granite parent materials in Benggang erosion areas was selected. Five levels of PAM application concentrations (0 %, 1 %, 3 %, 5 %, 7 %) were set. Through runoff scouring simulation experiments, the response patterns of sediment yield rate, detachment rate, and rill erodibility of sandy soils to PAM concentration under different hydraulic conditions were studied.[Results] ① PAM significantly reduced sediment yield, detachment rate, and rill erodibility, but dramatically increased critical shear strength (p<0.01). Additionally, the sediment yield reduction effect of PAM showed a decreasing and stabilizing trend with increasing scouring time, but gradually increased with increasing application concentration, with the most pronounced average sediment reduction effect observed when PAM concentration was within 5 %. ② There was a highly significant negative correlation between soil detachment rate and PAM application concentration (p<0.001). However, as PAM application concentration increased, the rate of decrease in soil detachment rate gradually slowed down, and the effect of PAM (F=37.39, p<0.001) on soil detachment and sediment yield processes was greater than the shear strength of runoff (F=15.38, p<0.001). ③ The ratio of rill erodibility between the PAM-treated groups and the control showed a quadratic function relationship with PAM concentration (R²=0.996, p<0.001), and the efficiency of reducing rill erodibility was most significant at 5 % PAM.[Conclusion] The application of PAM effectively reduced the sediment yield rate, detachment rate, and rill erodibility of granite-derived sandy soil and increased its critical shear force. The improvement effect of PAM application showed a continuous increasing trend when the PAM application concentration was below 5 %. However, when the PAM application concentration exceeded 5 %, the improvement effect showed only a slight change. Therefore, 5 % should be considered as the concentration threshold for PAM to improve the erosion resistance of granite-derived sandy soil.

Abstract:[Objective] The variation characteristics of wildfires and determine the correlation between the number of wildfires and soil moisture at different depths were analyzed in order to provide a scientific basis for evaluating the construction of ecological civilization and human production and life.[Methods] We used SNPP/ⅦRS satellite fire monitoring, fire site, and SMAP soil moisture data with statistical methods to analyze the change characteristics of wildfires on the Indo-China Peninsula from 2016 to 2021, and to explore the correlation between number of wildfires and soil moisture at 0-5 cm and 0-100 cm under different dry and wet conditions.[Results] ① Wildfires and burned areas on the Indo-China Peninsula mainly occurred from February to April in a year. The number of wildfires and burned areas had a high consistency in spatial and temporal distribution, mostly being concentrated in the border area between Western Myanmar and India, the area east of Central Myanmar, and Northern Laos. ② From February to April, fires mainly occurred in forest land, shrub land, and cultivated land, and were prone to occur in regions where the normalized difference vegetation indices (NDVI) were as below:0.2

Abstract:[Objective] Developing condition and early warning research was studied with regard to the security of Shaanxi regional innovation ecosystem in order to provide a theoretical basis for the safe development of Shaanxi regional innovation ecosystem. [Methods] A security measurement index system of the regional innovation ecosystem was constructed based on the niche perspective that included the four dimensions of openness, growth, synergy, and sustainability. The security status of the regional innovation ecosystem in Shaanxi Province from 2011 to 2020 was measured and analyzed by using a niche suitability model. The BP neural network model was used to predict the evolution trend of the regional innovation ecosystem security alarm in Shaanxi Province from 2021 to 2024. [Results] ① The security status of the regional innovation ecosystem in Shaanxi Province showed a steady increase during 2011—2020, indicating that regional innovation development had a good foundation and potential. ② The security status of the regional innovation ecosystem in Shaanxi Province would continue to improve from 2021 to 2024, but the status would still be lower in the north and south and higher in the central part of the province. [Conclusion] The security status of regional innovation ecosystem in Shaanxi Province shows a good trend of evolution, but the innovation ecosystem security of prefecture-level cities has obvious polarization. Therefore, it is still necessary to take relevant measures to further narrow the gap between regions so as to promote the healthy development of Shaanxi regional innovation ecosystem.

Abstract:[Objective] The health status of the living community of mountains-rivers-forests-farmlands-lakes-grasslands in source area of Qiantang River of Zhejiang Province were analyzed in order to provide scientific reference for land spatial planning and ecological management.[Methods] Based on life community theory and VOR (vitality-organization-resilience) ecological model theory, a health evaluation index system of life communities was constructed. Using 3S technologies and socioeconomic statistics, the health status of the life community in the Qiantang River source area was evaluated and graded (with the county as the evaluation unit).[Results] ① The life community health index of Chunan County in 2020 was classified as healthy, but the life community health indexes of Jiande City, Kaihua County, and Changshan County were classified as sub-healthy. ② From 2015 to 2020, the overall life community health index of the Qiantang River source area showed an upward trend, and the upward trend decreased in the following order:Jiande>Changshan>Chun'an>Kaihua. ③ Among the four counties (cities) in the Qiantang River source area in 2020, Changshan County had the best health status for the mountains-rivers-forests-farmlands-lakes-grasslands subsystem, while Chun'an County had the worst health status. Chun'an County had the best health status for the ecosystem subsystem, while Changshan County had the worst health status. ④ The structure and ecological service function of the forests and farmlands subsystems in the Qiantang River source area needs to be improved and optimized. ⑤ The ecological restoration pilot project in the Qiantang River source area had played a positive role in improving the health status of the life community to some degree.[Conclusion] The ecological restoration pilot project of mountains-rivers-forests-farmlands-lakes-grasslands in the Qiantang River source area has achieved various stages of results. The four counties (cities) should next carry out relevant restoration work to address the different problems of the mountains, rivers, forests, farmlands, and lakes subsystems. At the same time, governments should carry out comprehensive planning and ecological renovation in order to achieve more scientifically integrated governance, health management, and sustainable management for the mountains-rivers-forests-farmlands-lakes-grasslands community system.

Abstract:[Objective] The prediction accuracy of a regional landslide stability evaluation model was improved to solve the shortcomings of over-prediction caused by over-simplification of the landslide occurrence mechanism and the mechanical mechanism based on the static physical model of the traditional landslide stability analysis, and to determine the typical spatial-temporal variability and uncertainty of model parameters.[Methods] The data assimilation method of ensemble Kalman filtering was used to construct a regional landslide data assimilation scheme based on the TRIGRS model and SBAS-InSAR observation data in the area around the North Ring Road of Lanzhou City, Gansu Province. The coefficients of safety (F_s) in the model were assimilated, and the model parameters for the internal friction angle were updated. Then landslide stability was corrected and root-mean-square deviation (RMSD) was used to test the accuracy of the assimilated values.[Results] After assimilation, the landslide safety coefficient of the study area was significantly greater than the coefficient value predicted by the model, and the percentage of unstable area was reduced from 12 % to 7 %, which was closer to the actual observed value. The test gradually corrected the internal friction angle parameter towards the observed value, and realized the dynamic updating of the model parameters. The root-mean-square deviation decreased from 0.33 to about 0.04.[Conclusion] The data assimilation method based on the ensemble Kalman filter effectively corrected the model stability prediction results so that the actual situation of landslides in the current region was more accurately reflected with greater prediction accuracy.

Abstract:[Objective] The purposes of this study were to provide a scientific foundation for the prevention and control of agricultural non-point source pollution, and to promote coordinated development between agriculture and animal husbandry by calculating and analyzing livestock manure load of farmland and land carrying capacity.[Methods] We considered the comprehensive utilization rate of livestock and poultry waste, and employed the method of the pollution generation and discharge coefficient and the method of the nutrient-balance to separately calculate livestock manure load of farmland and land carrying capacity in different regions of Hunan Province in 2020. The spatial layout of livestock and poultry breeding and the distribution of manure pollution were analyzed by utilizing data regarding livestock manure and crop yield in Hunan Province.[Results] A total of 4.27×10⁷ pigs were bred in Hunan Province in 2020, with significant variation across regions. The loads of livestock and poultry manure, TN, and TP on farmland in Hunan Province were 19.04 t/hm², 94.85 kg/hm², and 24.99 kg/hm², respectively, and the cultivated land load alert levels all exceeded level Ⅱ, posing a slight threat to the farmland environment. At least two farmland load warning levels in Yongzhou, Loudi, Huaihua, and Chenzhou City reached level Ⅲ or above, indicating a heightened environmental risk. The maximum land carrying capacity of livestock and poultry breeding land was 1.23×10⁸ pig equivalents, but the currently raised pig equivalents only accounted for 37.18 % of this value. This result indicated that there was significant potential for increasing the livestock breeding capacity in various cities, with seven cities (Changde, Yiyang, Yueyang, Shaoyang, Changsha, Yongzhou, and Hengyang City) capable of breeding more than 5.00×10⁶ pig equivalents. Given the absence of breeding overload within these regions, crop managers in woodland and orchards in Yongzhou, Loudi, Huaihua, and Chenzhou City were encouraged to increase their application of organic fertilizers and manure absorption to lower the risk of farmland pollution.[Conclusion] Overall, the risk posed by livestock and poultry breeding to the farmland environment in Hunan Province remains relatively low, suggesting substantial potential for future industry expansion. However, certain regions are facing farmland pollution risks, thus necessitating a redirection in manure disposal to lessen the pressure of manure absorption on farmland, thereby promoting sustainable agricultural development.

Abstract:[Objective] Refined survey and mapping data were used to simulate urban rainfall and runoff processes in order to activate land resource data assets and to promote precise urban flood risk management and control.[Methods] The study was conducted in the Panyu District of Guangzhou City. The SCS-CN runoff model and GIS technology were used to simulate the depth of urban flood inundation under different intensity rainstorm situations on the basis of high-precision topographic and architectural data in order to quantitatively analyze the characteristics of inundation risk in the study area. Additionally, a loss experience model of disaster-bearing bodies was used to assess flood loss risk and to identify highly vulnerable areas.[Results] ① The flood inundation risk area in Panyu District was spatially clustered with rivers and low-lying urban areas, and the streets and towns near the Shiqiao-Shawan watershed and the Sanzhixiang-Dashi watershed had higher inundation risks. ② Agricultural land and construction land were expected to be most severely affected as the intensities of rainstorms increased. ③ For the case of a 100-year rainstorm, four planning management units in Panyu District were at high risk of loss, and their losses mainly came from residential buildings, while the units facing medium risk of loss were mainly associated with agricultural land inundation.[Conclusion] Refined survey and mapping data can effectively identify the distribution of high loss areas that are prone to potential inundation. These results are in line with the actual situation. The study results can provide advance research and planning support for urban flood control and sponge city development and construction.

Abstract:[Objective] Based on the ERA5 reanalysis of precipitation data from 1950 to 2022, the spatiotemporal variation characteristics of precipitation in the water source area and water receiving area of the south-to-north water transfer project were explored in order to ensure the feasibility and sustainability of inter-basin water transfer, and provide a scientific reference for water resource scheduling and operation management of the middle route project of south-to-north water diversion project.[Methods] The Mann-Kendall test, wavelet analysis, cloud model, and Copula function were used to analyze the trend of precipitation change and the characteristics of drought-waterlogging encounters in the water source area and the water receiving area.[Results] ① During 1950-2022, annual precipitation in the water source area and the water receiving area of the south-to-north water diversion project has decreased by 34.75 mm/(10 yr) and 39.35 mm/(10 yr), respectively. The annual precipitation in the water source area and the water receiving area exhibited a main cycle of 43 years and 55 years, respectively; ② Precipitation in the subordinate cloud map was unevenly distributed and discretely dispersed in summer, while precipitation distribution was uniform and concentrated in winter; ③ The unfavorable water diversion encounter frequencies for the flood season and the non-flood season were 23.15 % and 25.92 %, respectively.[Conclusion] Annual precipitation in both the water source area and the water receiving area showed a decreasing trend. The alternating change of precipitation between the wet season and the dry season in the source area was significant. The probability of asynchronous drought-waterlogging was greater than that of synchronization, and the frequency of simultaneous drought in the north and the south was relatively low, which increased the safety and reliability of water diversion projects. These research results provide a theoretical basis for the formulation of relevant policies and technical guidance for the middle route project of the south-to-north water diversion project, and will be helpful in project planning and management, thereby improving the efficiency and sustainability of water resource utilization.

Abstract:[Objective] Runoff and sediment characteristics of three rivers in China were compared based on data updated dynamically, in order to provide a basis for basin development and management. [Methods] Runoff and sediment data for the Yellow River (Lijin station), Yangtze River (Datong station), and Pearl River (Gaoyao, Shijiao, Boluo stations) from 1960 to 2020 were used with the moving average method, the Pettitt test method, the double mass curve method, and the wavelet transform method to study the trend, mutagenicity, and periodicity characteristics of runoff and sediment fluxes. Additionally, the cross wavelet transform and wavelet coherence spectrum were used to investigate the resonance period and coherence of runoff and sediment flux. [Results] The runoff and sediment fluxes of the Yellow River, Yangtze River and Pearl River into the sea have changed significantly during the past 60 years. Runoff and sediment discharge of the Yellow River decreased in 1986, and the sediment volume decreased abruptly again in 1997. Runoff of the Yangtze River and Pearl River fluctuated and the sediment discharge decreased abruptly in 1992 and 1999, respectively. The runoff and sediment changes for the three rivers were characterized by significant interannual and interdecadal cycles. Specifically, the interdecadal co-evolution cycles of runoff and sediment in the Yellow River, Yangtze River, and Pearl River were concentrated before 1980, 1990, and 2000, respectively, and the interannual co-evolution cycle was five years, with frequent“abundance-depletion”transitions. The results of the cross wavelet analysis showed that the runoff and sediment of the three rivers exhibited a significant 1—3 year resonance cycle with predominantly positive phase evolution during 1965—1975. [Conclusion] The runoff and sediment fluxes into the sea of the three major rivers of China were characterized by significant trend, mutagenicity and periodicity. Watershed development and management would be more effective in accordance with those characteristics.

Abstract:[Objective] The intensity of spatial conflicts was measured and ways to strengthen the management of territorial space conflicts were determined at county scale, and the utilization of territorial space was optimized in different regions in order to provide new ideas for the sustainable development and utilization of territorial space at the county level.[Methods] Taking Yihuang County in Jiangxi Province for example, the three methods of landscape ecological index model, exploitable intensity analysis, and land use status and suitability evaluation were used in conjunction with guidance provided from the comprehensive perspective of "grasp landscape pattern-clarify development intensity-determine suitability-realize function optimization" to construct a comprehensive spatial conflict measurement model. Impact type areas with significant spatial conflicts coupled with regional bases at the township scale were identified, and functional optimization measures were proposed.[Results] ① At Yihuang County from 2010 to 2020, urbanization expanded and the accommodation degree of ecological space declined. The main change trend was that the agricultural production space and ecological space were transferred to the industrial and mining production space and the urban living space. ② From 2010 to 2020, the intensity of regional conflicts intensified, and there were significant differences in intensity and distribution in different periods and regions. The controllable space was mainly located in the southern part of the study area. The mild and moderate conflicts were evenly distributed in the region. The severe conflicts were mainly located in the northern, central, and eastern areas. ③ According to the analysis of development intensity and the causes of conflict, the towns and villages could be divided into three categories:disadvantaged areas of terrain development, intensive areas of urban development, and concentrated areas of nature protection, which are the key points of spatial function optimization; ④ At the township scale, there were differences in the distribution of spatial conflict types, and the conflict areas followed the order of agricultural space and ecological space conflict > urban space and ecological space conflict > urban space conflict > agricultural space conflict; ⑤ From the comprehensive conflict measurement model, it can be concluded that there were eight kinds of comprehensive conflict combinations within the region, which could be divided into five conflict types after merging:disorderly urban expansion, urban scale expansion, improper urban planning, overall development lag and urban development lag.[Conclusion] The intensity of spatial conflicts in Yihuang County increased during 2010 to 2020, and regional ecological security and food security were constantly challenged. Therefore, regional control of spatial conflicts should be strengthened to optimize the development and utilization of regional territorial space resources.

Abstract:[Objective] The characteristics of the spatial dynamics of wind erosion at Wuwei City, Gansu Province and the controlled area of wind erosion and its prevention countermeasures were determined in order to provide scientific references for implementing measures to prevent wind erosion, conserve soil and water, and use ecological environmental construction practices in the city.[Methods] Multi-source geographic information data, applied remote sensing, a geographic information system (ArcGIS), and other technical means were used with the revised wind erosion equation (RWEQ) to calculate the five-period wind erosion modulus of Wuwei City from 2000 to 2020 to obtain the distribution of the regional wind erosion area, change characteristics, etc. These results were combined with a superposition analysis of spatial elements (such as the distribution of key construction projects) to put forward the principles of the city's wind erosion manageable area delineation and to apply them to delineate the manageable area of wind erosion at Wuwei City.[Results] RWEQ was able to estimate the multi-year wind erosion modulus at Wuwei City[5 788.98 t/(km²·yr)], with a multi-year average soil wind erosion of 1.92×10⁸ t. The model exhibited an overall decreasing and occasionally increasing trend over time, and the wind erosion intensity level was obviously weakened. Wind erosion intensity exhibited obvious spatial heterogeneity that was mainly located in Minqin County, Liangzhou District, and Gulang County. According to the multi-element superimposed wind erosion zoning management program, Wuwei City can manage a total of 2 872.66 km² of wind erosion area, of which 1 468.48 km² was at Minqin County, 708.75 km² was at Liangzhou District, and 695.43 km² was at Gulang County.[Conclusion] Wind erosion sub-area management should be the focus of wind erosion prevention and soil and water conservation in Wuwei City. According to the results of the wind erosion sub-area management division, for different administrative divisions, the flat Gobi desert area with low slope in the northern part of Minqin County is the key area of regional concern. Management measures should be based on the prevention of wind and sand erosion and the restoration of vegetation cover, and attention should be given to controlling the impact of man-made engineering and construction disturbances to make clear the scope of the regional management. Liangzhou District should focus on using a combination of engineering measures and biological measures, combined with governmental management. Gulang County should focus on closure measures and protecting natural vegetation. At the same time, special attention in the Gobi desert area should be given to the implementation of wind and sand erosion prevention and ecological restoration measures for construction activities such as large-scale photovoltaic power plants.

Abstract:[Objective] Different soil remediation treatment needs in the Changchun-Jilin-Tumen region were determined and the characteristics of supply and demand were matched based on the spatio-temporal variations of soil conservation service founction in the region in order to provide a scientific basis for promoting the effective implementation of regional soil ecological protection.[Methods] The InVEST model was used to quantitatively assess the soil conservation service functions of cities and counties in the Changchun-Jilin-Tumen region in 2000, 2010, 2020. The relationship between the supply and demand of soil conservation services and their spatial and temporal changes were analyzed in order to identify the priority areas in need of targeted management and to formulate soil remediation strategies.[Results] From 2000 to 2020, the soil conservation intensity of the Changchun-Jilin-Tumen region ranged from 0.00 to 2 590.42 t/km²; the erosion reduction service function ranged from 0.00 to 1 544.23 t/km², and the sediment retention service function ranged from 0.00 to 2 452.20 t/km², with significant differences in soil conservation service levels between regions and obvious spatial and temporal differentiation characteristics. The supply and demand matching situation in the study area was relatively balanced, and there was no low supply and high demand matching type. There were four matching types between supply and demand of regional soil conservation services:Soil conservation services were sustainable when supply and demand increased simultaneously and when supply increased and demand decreased; Soil conservation services were not sustainable when both supply and demand decreased and demand increased while supply decreased. The proportion of unsustainable areas in need of treatment increased over time, accounting for 68.15 % (erosion reduction) and 72.57 % (sediment retention) by 2020, concentrated in the east and west parts of the study area. In the middle part of the study area, the soil retention service was significantly weakened.[Conclusion] In the study area, the spatio-temporal variations in soil conservation service founction were obvious, and the central-eastern part, eastern tail end, and western part of the Changchun-Jilin-Tumen region were identified as the soil sensitive area, soil fragile area, and soil restoration area, respectively. Soil ecological management work in these areas should focus on soil remediation, soil conservation, and soil restoration, respectively.

Abstract:[Objective] A high-precision geological hazard susceptibility evaluation model was determined for the three districts (counties) of Lishi, Shilou, and Liulin in Lüliang City, Shanxi Province in Luliang mountaionous area in order to provide auxiliary decision-making support for regional planning in the area.[Methods] Based on a geographic information system, a sample of 525 historical hazard points and 500 randomly selected non-hazard points in the region were used, and 19 influencing factors of geological hazard were selected. Geographic detectors (GD) were used to judge the relative importance of each factor. Correlation tests and filtering index factors were determined on the Jupyter Notebook platform. Based on the information method (IM), a method was proposed to calculate the amount of information provided by disaster points combined with the amount of information provided by non-disaster points to obtain the improved information method (IIM), and to calculate the weight with the help of the spatial heterogeneity q value of geographic detectors. Six evaluation systems (GD-IIM, GD-IM, GD-CF, IM, CF, and IIM) were established using the certainty factor (CF). The natural breakpoint classification method was used to divide the susceptibility into five, four, and three levels, and the accuracy of the partition results was verified by the seed cell area index (SCAI). The accuracy of the model results was compared with the ROC curve.[Results] After SCAI testing, the models were divided into four levels (very low, low, high, and very high) that met the rationality requirements. The success rate and prediction rate of disaster susceptibility evaluation by the GD-IIM model reached 90.5 % and 85.5 %, respectively. The IIM model exhibited 2 %~4 % greater accuracy than the traditional IM and CF statistical methods.[Conclusion] The bivariate statistical method coupled with geographic detectors produced more accurate results in constructing the vulnerability evaluation prediction model in the study area. Model construction that considered the non-disaster point information was more accurate than the IM model that considered only the disaster point information model. The improved model was suitable for local model construction.

Abstract:[Objective] The main grain producing areas have an important strategic position in achieving stable grain production and supply. The cultivated land use efficiency and its spatiotemporal evolution characteristics in the main grain producing areas were studied to promoting the efficient use of cultivated land resources in the main grain producing areas, and ensuring food security and realizing sustainable agricultural development.[Methods] The two-stage dynamic network DEA model was innovatively used to measure cultivated land utilization efficiency of 179 prefecture-level cities in the main grain producing area from 2010 to 2020. The spatial and temporal evolution characteristics of cultivated land use efficiency were analyzed by ArcGIS visualization technology and kernel density estimation. The Tobit model was constructed to explore the influencing factors of cultivated land utilization efficiency.[Results] The overall efficiency level of the main grain producing area from 2010 to 2020 was characterized as "small decline-rapid rise-fluctuating growth", and the overall efficiency level was low and still had great capacity for improvement. The efficiency level of the production stage was always higher than that of the consumption stage. The gap between the efficiency levels of the two stages had a tendency to further increase. The increase in cultivated land utilization efficiency in the main grain producing area was influenced by the combined effect of the efficiency levels during the two stages, with the production stage being the main driver of efficiency improvement. Resistance to improvement came from the efficiency during the consumption stage. By region, cultivated land utilization efficiency followed the order of Songhua River basin>Yangtze River basin>Yellow River basin, with significant regional imbalance. From the spatial point of view, the overall efficiency and high value areas of production stage efficiency were spatially distributed from northeast to southwest, and gradually formed a spatial pattern of "high-high" clustering and "low-low" clustering. The high value areas of consumption stage efficiency showed a discrete distribution pattern, and did not show the development trend of convergence in the direction of improvement. The external influencing factors of the overall, production, and consumption stages were different, involving the level of socio-economic development, urban and rural development, science and technology, and agricultural infrastructure construction. There were significant differences in the intensity and direction of different factors on the overall and sub-stage cultivated land use efficiency in different regions.[Conclusion] In the future, the main grain producing areas should not only explore the path of regional differentiated cultivated land use, strengthen cooperation among prefecture-level cities, but also focus on the convergence speed of efficiency improvement in consumption stage and the coordination with the efficiency gap in production stage while improving the efficiency of production stage.

Abstract:[Objective] The status and spatial distribution of soil erosion in hilly areas were determined in order to provide a theoretical basis for limiting local soil erosion and improving soil conservation practices.[Methods] The study was conducted at Zhangjiajie City, Hunan Province in the hilly area of Southeast China. The revised universal soil loss equation (RUSLE) and geoprobe were used to to determine the spatial and temporal changes of soil erosion characteristics and to determine the driving factors of soil erosion.[Results] ① Average soil erosion values at Zhangjiajie City in 2000, 2010, and 2020 were 1.03×10⁷, 2.05×10⁷, and 6.74×10⁶ t/a. Average soil erosion over the 20-yr study period initially increased and then decreased. ② Soil erosion was dominated by forest erosion. Other land feature types showed different degrees of erosion, in which erosion was mainly concentrated in the 8°-35° slope area. Erosion intensity increased with increasing slope. ③ Soil erosion in the study area was affected by vegetation cover, slope, soil properties, and elevation. The most obvious factor affecting erosion was vegetation cover. The strongest interaction factor influencing erosion was found to be between slope and vegetation cover.[Conclusion] The distribution of soil erosion at Zhangjiajie City had obvious spatial and temporal differences. Soil and water conservation should be carried out reasonably on the premise of ensuring ecological security in the future.

Abstract:[Objective] The spatial and temporal evolution of land use in Chongqing City were analyzed, and the relationship between the evolution characteristics of land use transformation and landscape pattern response and urbanization was explored in order to provide data support for ecological-production-living spaces land planning and sustainable development of urbanization in Chongqing City.[Methods] A land use classification criteria was constructed based on the perspective of the functional classification of ecological-productional-living spaces; utilizing land remote sensing images and nighttime lighting data in 2000, 2010, and 2020; and adopting the transfer matrix, correlation analysis, and regression analysis methods.[Results] ① From 2000 to 2020, the productional and ecological space of Chongqing City generally decreased, and the living space continued to expand. From 2000 to 2010, the productional and ecological space decreased by 191.87 km² and 252.95 km², respectively, and the living space increased by 446.03 km². From 2010 to 2020, the productional space decreased by 13.76 km², ecological space decreased by 324.05 km², and living space increased by 314.87 km². ② The shift of productional functions to living functions was more obvious in Chongqing City. As urbanization intensified, ecological space shifted significantly to productional space, and the shift in function was obviously gathered in the central region of Chongqing City. ③ The spatial landscape fragmentation of Chongqing City decreased, the landscape complexity gradually increased, and the forest, grass, and water ecological space dominated. ④ There were differences in the influence of land use area changes on nighttime light in 2000-2010 and in 2010-2020. In 2000, changes in urban living space and rural living space played a dominant role in influencing changes in nighttime light, while changes in industrial production space and urban living space in 2020 had a stronger influence on changes in nighttime light.[Conclusion] Various types of space in Chongqing City have been transformed into each other, and the relationship between changes in different ecological-productional-living spaces types and urbanization has been utilized to promote the coordinated development of land planning and urbanization.

Abstract:[Objective] The impacts of land use on terrestrial ecosystems are important for current global change research. The impacts of land use change on fractional vegetation coverage (FVC) were analyzed scientificaly to improve coordinated development of the social economy and ecological environmental quality while balancing development of the regional economy, in order to provide a reference for government departments to use in protecting and restoring regional ecological management.[Methods] Hubei Province was selected as the research area. Landsat remote sensing images and land use remote sensing data from 2000 and 2020 were obtained, and methods such as spatial processing of remote sensing data, a pixel binary model, and a land use transfer matrix were used. The temporal and spatial changes in FVC, land use type changes, and their effects on FVC in Hubei Province were analyzed.[Results] ① From 2000 to 2020, the area of cultivated land, grassland, and unused land in Hubei Province decreased, the area of water and construction land increased, and the area of forest land remained basically unchanged. The land use area sizes followed the order of forest land > cultivated land > water area > construction land > grassland > unused land; ② The average FVC in Hubei Province increased by 6.50 %. The average FVC of forest land, cultivated land, grassland, and unused land increased, while the average FVC of construction land decreased. ③ FVC in Hubei Province showed an overall increasing trend. The areas with increased FVC were mainly concentrated in the west and southeast parts of Hubei Province. Some areas also experienced vegetation degradation, mainly concentrated in the central and southern parts of Hubei Province and some areas in Northern Xiangyang. ④ During the FVC transfer process resulting from changes in land use types, the transfer process between higher FVC and high FVC areas of cultivated land was the most intense. The FVC transfer amount in forest land accounted for 47.87 % of the total transfer amount, while the FVC transfer amount for grassland accounted for only a small proportion of the total transfer amount (3.40 %).[Conclusion] Land use changes in Hubei Province were great from 2000 to 2020, resulting in an overall increase in FVC over time.

Abstract:[Objective] The ecological product values (EPV) in Hebei Province were evaluated and the driving factors of their spatial change were also explored, in order to provide a scientific foundation for establishing an ecological security barrier in the Beijing-Tianjin-Hebei region while expediting ecological civilization development.[Methods] The EPV were computed for 168 counties in Hebei Province during 2010, 2015, and 2020 by use of the equivalent factor method. Spatial distribution evolution and clustering characteristics were analyzed utilizing the global Moran index, high/low clustering index, and the hotspot analysis method. Geographic detector was employed to identify the primary driving forces.[Results] ① Between 2010 and 2020, Hebei Province's EPV surpassed 3.80×10¹¹ yuan, exhibiting notable overall improvement. EPV exhibited a pattern of gradual increase followed by rapid growth, exceeding 4.20×10¹¹ yuan by 2020. Forest land had the highest EPV, consistently dominating the ecological product types. Water areas had the next highest EPV, and experienced the most substantial changes in both amount and rate. ② During 2010 to 2015, EPV's spatial distribution exhibited a north-south and west-east dichotomy, with high values concentrated in the Northern Yanshan and Bashang Plateau regions, as well as in the Western Taihang Mountain area, while lower values clustered in the Southeastern Hebei Plain. During 2015 to 2020, the north-south divide persisted, with added east-west variation and central low values. ③ From 2010 to 2020, significant high-value clustering was observed spatially, mirroring the distribution pattern of cold and hot spots. ④ Single-factor analysis identified CO surface concentration, O₃ concentration, and average annual temperature as primary influencers of EPV's spatial evolution. Per capita GDP emerged as the secondary vital factor, while the impact of social factors remained comparatively weak. Dual-factor interaction analysis revealed that the leading combinations of factors during the three periods were per capita GDP ∩ NO₂ surface concentration, elevation ∩ O₃ concentration, and per capita GDP ∩ CO surface concentration, with corresponding q values of 0.71, 0.73, and 0.66, respectively.[Conclusion] While forest land and water areas hold pivotal roles in augmenting EPV, significant spatial disparities exist. To drive more positive transformations, it is essential to not only consider robust ecological single-factor drivers, but also to comprehensively grasp the intricate and nonlinear nature of driving force origins.

Abstract:[Objective] While financial proceeds from mining can promote the local economy, mining also has a profound impact on the surrounding ecological environmental quality. The ecological status of mines and their surrounding areas were monitored and quantitatively evaluated based on multi-source and long time-series remote sensing data to serve for green mine construction and sustainable development, and also play a positive demonstration role with regard to ecological restoration and management of mine areas.[Methods] This study was conducted at intelligent mine sites and its surrounding area (within 5 km) in Yongjing County, Gansu Province. Multi-spectral remote sensing images acquired by the Landsat series of satellites for five periods from 2009 to 2022 were used with high-resolution remote sensing images from the high-resolution series satellites and the planet series satellites during the same period to monitor and identify the important surface changes and time nodes of the mine and its surrounding area. The spatial and temporal distribution pattern, variation characteristics, and influencing factors of ecological quality in this region during this time period were also systematically determined.[Results] ① The ecological quality of intelligent mine areas in Yongjing County continuously declined from 2009 to 2019, and the remained stable after 2019. The mining area had little impact on the ecological quality of the surrounding area. ② The spatial-temporal change analysis of the remote sensing ecological index for the mining areas at Yongjing County indicated that changes in greenness and heat indicators were more significant than changes in dryness and humidity indicators. ③ The preliminary work of backfilling, leveling, and trimming slopes for land reclamation at abandoned mine sites can significantly increase the remote sensing ecological index value.[Conclusion] The remote sensing ecological index can objectively reflect the actual state of the ecological quality of a mining area. Actions such as land reclamation of abandoned mines and the transformation of surface operations to underground operations in mining areas can effectively solve the problem of continuously declining ecological quality in mining areas.

Abstract:[Objective] The dynamic changes in grassland habitat quality and its influencing factors in Xilingol League, Inner Mongolia were studied to provide a scientific theoretical basis for the formulation of ecological environmental protection policies and high-quality development in this area.[Methods] The remote sensing ecological index (RSEI) was constructed by using the Google Earth Engine (GEE) platform and MODIS data to evaluate the habitat quality of the study area. Spatial heterogeneity and influencing factors of RSEI were analyzed by using the Moran index and geographic detector.[Results] ① The results demonstrated a temporal change in habitat quality in the study area, with quality initially deteriorating and later improving from 2000 to 2021. The ecological environment significantly improved over time. Habitat quality was better in the typical steppe of central China and the meadow steppe of Eastern China, while it was worse in the desert steppe of Western China. ② The global Moran's I for the five-year study period exceeded 0.935, indicating a strong positive spatial correlation in the distribution of RSEI within the study area, primarily characterized by high-high and low-low cluster patterns. ③ The geodetector results showed that greenness was the main factor affecting RSEI. The most significant influence on ecological environmental quality was the interaction between model factors and natural factors, followed by the coupling of model factors and socio-economic factors.[Conclusion] The areas of high-value habitat quality in the eastern region of the Xilingol League should continue to strengthen protection of the ecological environment, and the areas of low-value habitat quality in the west should focus on restoration and management of desert grasslands and on curbing the eastward expansion of desert.

Abstract:[Objective] The changes of ecological environmental quality were analyzed at Shenmu City of Shaanxi Province, an important area for ecological protection and construction in the Yellow River basin, in order to provide a scientific basis for ecological environmental management, restoration, and green development in this resource-based city.[Methods] Landsat remote sensing images in 2010, 2015, and 2020 were selected, and the remote sensing ecological index (RSEI) was constructed as an ecological environmental evaluation index by using the principal component analysis method to analyze the spatial and temporal evolution pattern of ecological environmental quality in Shenmu City. The ecological environmental driving mechanism in the area was determined by Geodetector.[Results] ① The ecological environmental quality of Shenmu City deteriorated over time, with the decline in RSEI reaching 12.47 %, decreasing the fastest from 2010 to 2015. The area with poor ecological environmental quality in Shenmu City increased by 15.29 %. ② The ecological environmental quality in Shenmu City deteriorated first in the sandy area in the northwest (enhanced by wind), and then shifted to the southeast and northeast where the elevation was lower. Meanwhile, the dominant ecological environmental quality in Shenmu City was categorized as poor and fair. The area of those two categories occupied 67.09 % of the total area of Shenmu City. ③ The four indicator factors of vegetation cover and greenness, humidity, dryness, and heat were identified as significant drivers of ecological environmental quality in Shenmu City. Vegetation cover was the main driver of ecological environmental quality, accounting for 62.40 % of the variation in ecological environmental quality. The multi-factor interactions also all indicated synergistic enhancement, and the interaction between night light, population density, heat, and vegetation coverage was the strongest.[Conclusion] The overall ecological environmental quality in Shenmu City has been deteriorating over time. Although the previous degradation has been contained, the area of deteriorating ecological environmental quality is gradually expanding. Increasing vegetation cover can effectively enhance the ecological environmental quality in Shenmu City. Therefore, ecological protection measures such as vegetation greening should be further implemented to improve the ecological environmental quality in Shenmu City.

Abstract:[Objective] The spatiotemporal evolution characteristics of cultivated land non-agriculturalization in Fujian Province from 1980 to 2020 were systematically studied based on county scale area, and the spatial distribution, migration law, and aggregation characteristics of cultivated land non-agriculturalization in Fujian Province were revealed in order to provide a basis for the protection and sustainable utilization of cultivated land resources in Fujian Province.[Methods] Based on land use data of Fujian Province in 1980, 1990, 2000, 2010, and 2020, a center of gravity model and spatial autocorrelation methods were used to analyze the spatio-temporal evolution characteristics of the non-agriculturalization of cultivated land in Fujian Province.[Results] ① The cultivated land resources in Fujian Province were mainly distributed in a belt-shaped manner along the southeastern coast, and the area of cultivated land decreased year by year over time. ② The spatial distribution of cultivated land non-agriculturalization in Fujian Province exhibited significant geographical differences, and the degree of cultivated land non-agriculturalization has been increasing, gradually expanding from the southeast coastal area to the entire province. The high grade areas of cultivated land non-agriculturalization were mainly distributed in the southeast coastal area and the northwest area, with the conversion of cultivated land mainly into construction land, forest land and grassland. ③ The gravity center of cultivated land non-agriculturalization in Fujian Province deviated from the geometric center, and its distribution was uneven. The center of gravity of cultivated land non-agriculturalization was mainly located to the southeast of the geometric center, shifting first to the southwest, then to the southeast, and then to the northwest. The degree of cultivated land non-agriculturalization in the southeastern part of Fujian Province was still greater than in the northwestern part of the province. The overall trend of the spatial pattern of cultivated land non-agriculturalization shifted over time from the southeastern part to the northwestern part of the province. ④ Cultivated land non-agriculturalization in Fujian Province showed a positive spatial correlation and a deepening spatial clustering. The spatial changes of the "high-high" and "low-low" agglomeration played a dominant role in the evolution of the spatial autocorrelation of cultivated land non-agriculturalization in Fujian Province, with the "high-high" agglomeration shifting from the southeast to the northwest, and the "low-low" agglomeration shifting from the southeast to the northwest. The "high-high" agglomeration shifted from the southeastern region to the northwestern region, and the number of "low-low" agglomeration decreased.[Conclusion] The degree of non-agricultural land in Fujian Province is deepening, the degree of spatial aggregation is strengthening and the center of gravity of non-agricultural land is gradually moving to Northwest China. In order to ensure food security and take into account economic development, reasonable measures should be taken to protect cultivated land and realize sustainable development of cultivated land resources.

Abstract:[Objective] Based on the land use data of five periods in Jiangxi Province from 2000 to 2020, the spatial and temporal evolution characteristics of habitat quality and the main factors of regional habitat quality change were studied, in order to provide references for land use planning and regional ecosystem service optimization in Jiangxi Province.[Methods] The InVEST habitat quality assessment model was used to measure the spatial habitat quality level in Jiangxi Province. The global Moran's I index was used to analyze the spatiotemporal correlation of habitat quality. The Geodetector model was used to capture the dominant factors affecting habitat quality.[Results] ① From 2000 to 2020, the overall habitat quality in Jiangxi Province was at a relatively high level, but showed a slow downward trend. ② The habitat quality in Jiangxi Province had a high spatial positive correlation, and the spatial distribution differences gradually increased. ③ In the natural socio-economic driving system, the proportion of forest land in land use type factors was the main controlling factor affecting habitat quality. The interactions between each driving factor were nonlinear enhancements, with the greatest interaction observed between the distance from construction land and the proportion of cultivated land.[Conclusion] The overall habitat quality level in Jiangxi Province was relatively high, with significant spatial distribution differences. Habitat quality level was mainly influenced by land use types.

Abstract:[Objective] A coupling and coordination model of sustainable intensification and scale of cultivated land was studied to provide scientific basis for formulating policies such as territorial spatial planning, rural revitalization and cultivated land protection.[Methods] Actual land use for a study area in Inner Mongolia was used to construct an evaluation index system of sustainable intensification and scale of cultivated land by the entropy method, and the sustainable intensification and scale of cultivated land were measured by the multi-factor comprehensive analysis method. A coupling and coordination analysis was carried out according to the evaluation results. Based on the evaluation results and regional status reported in the study area, we put forward specific suggestions for the utilization and protection of cultivated land in Inner Mongolia.[Results] The comprehensive level of cultivated land intensification in Inner Mongolia from 2006 to 2021 was between 0.218 and 0.370, showing an overall upward trend. The level of cultivated land intensification was higher in the east and west, and lower in the central region. The differences in cultivated land intensification level among all of the cities were small, and the utilization degree and output effect of cultivated land had a significant influence on the level of cultivated land intensification. The comprehensive level of cultivated land scale fluctuated between 0.433 and 0.532, showing a trend of initially increasing and then decreasing. The spatial distribution characteristics were irregular. There was a large difference in the scale level of cultivated land among the cities, and the shape and area of cultivated land patches had a high contribution to the scale level of cultivated land. During the past 15 years, the coupling degree of cultivated land intensification and scale in Inner Mongolia gradually developed from the run-in stage to the high-level run-in stage, and the coupling degree of cultivated land intensification and scale continued to increase. The coupling degree of cultivated land intensification and scale has advanced from the verge of disharmony and barely coordinated to primary coordination and intermediate coordination. However, 33.33 % of cities were still in the barely coordinated stage, and the spatial distribution pattern was generally higher in the eastern and western regions and lower in the central region.[Conclusion] There is room for optimizing the cultivated land utilization level in Inner Mongolia. More attention should be given to the scientific utilization of cultivated land, improving the planting environment, and attaching equal importance to the utilization and protection of cultivated land to promote sustainable and high-quality agricultural development in Inner Mongolia.

Abstract:[Objective] The characteristics of vegetation dynamic changes and their response relationship with potential impact factors in the Aksu River basin were determined in order to provide a theoretical basis for ecological environmental protection and governance in arid areas.[Methods] Based on MODIS normalized difference vegetation index (NDVI), climate, topography, soil type, and land use data, the dynamics and driving mechanisms of vegetation changes in Aksu River basin from 2000 to 2020 were analyzed using trend analysis and geographical detector methods.[Results] ① The NDVI of the Aksu River basin showed a significant increasing trend from 2000 to 2020, with a growth rate of 0.003 2/yr. The growth rate in the anthropogenic areas was significantly larger than in the non-anthropogenic areas. ② There were temporal and spatial differences in the explanatory power of potential factors for NDVI changes. Land use conversion was an important driving factor for NDVI changes in anthropogenic areas. Elevation, soil type, distance from glacier snowpack, and distance from water bodies were important driving factors for NDVI changes in non-anthropogenic areas. Interaction among factors increased the explanatory power of NDVI changes, and land use conversion interacting with soil type had the strongest explanatory power of NDVI changes in the anthropogenic areas. The interaction among background factors, distance from recharge water sources and other factors was an important combination of factors for NDVI changes in the anthropogenic areas. ③ More than 10 % of the area of the Aksu River basin in 2000-2020 underwent land use conversion, mainly in the form of mutual conversion of bare land and grassland, and a significant increase in the area of cropland, woodland, shrubland, and man-made land surface.[Conclusion] The spatial and temporal characteristics and driving mechanism of NDVI change in human activity area and non-human activity area in Aksu River basin are different. It is necessary to manage the Aksu River basin reasonably according to local conditions to promote the benign development of ecological environment in the basin.

Abstract:[Objective] The changes and impact of regional ecosystem services and ecological risks were studied in order to provide decision-making support for the rational utilization of land resources and ecological restoration of territorial space.[Methods] Landsat remote sensing images were used with the random forest classification method of the GEE (Google Earth Engine) platform to extract land use change information for Kunming City, Yunnan Province from 1990 to 2020. A spatial dynamic change analysis was carried out based on the interpretation results. The equivalent factor method was used to estimate ecosystem service values. An ecological risk model was used to determine the change in ecological risk over time. The correlation between ecosystem service value and ecological risk was calculated with a bivariate spatial autocorrelation model.[Results] ① Among the land use types in Kunming City from 1990 to 2020, forest land and grassland occupied the largest area, the area of construction land increased significantly, and the area of cultivated land, grassland, and forest land decreased. ② The value of ecosystem services in Kunming City showed an overall upward trend over time, with a total increase of 3.08×10⁸ yuan. The effective implementation of ecological protection policies increased the value of ecosystem services. Ecological risks during the study period were mainly classified as medium and low risks, and accounted for 79 % of the total area. The overall average ecosystem service value decreased by 0.12, indicating that urban economic development had developed with little impact on the environment. ③ Ecological risk had a certain impact on the change of ecosystem service value, and with the passage of time, the area of high-value and high-risk areas gradually decreased, and the area of low-value and low-risk areas gradually increased, without obvious extremes.[Conclusion] The combination of regional ecosystem service value and ecological risk can better characterize changes in ecological environment of Kunming City caused by human activities, and provide decision-making and management references for environmental protection and high-quality sustainable development. effectively prevent ecological risks, and make the economic development and environmental protection of Kunming City develop to a benign situation.

Abstract:[Objective] The spatio-temporal variation characteristics of vegetation cover since returning farmland to forest were systematically analyzed. The potential of vegetation restoration were evaluated, in order to provide scientific theoretical basis and implementation suggestions for the sustainable development of ecological environment construction in Shaanxi Province.[Methods] The spatial and temporal variations of fractional vegetation cover (FVC) were investigated from 2000 to 2020 based on MODIS NDVI data, the Sen+Mann-Kendall method and Hurst index. Vegetation restoration potential was assessed by using the 'similar habitat method' in Shaanxi Province, as well as in three subregions of the Loess Plateau, Qinling-Bashan Mountain, and the Guanzhong Plain.[Results] ① The average growth rate of FVC in Shaanxi Province was 0.002 9/a from 2000 to 2020, and 74.58 % of the area had increased in FVC. Areas of significant and slight FVC increase were detected in the Loess Plateau and Qinling-Bashan Mountain where 84.46 % and 74.40 % of the areas, respectively, showed increased FVC. Slight FVC degradation trends were detected in the Guanzhong Plain where 64.56 % of the area, showed decreased FVC. ② The areas showing persistent increase in FVC accounted for 19.80 % of the entire Shaanxi Province, and accounted for 27.83 % and 13.68 % in the Loess Plateau and Qinling-Bashan Mountain, respectively. The area showing persistent decreases in FVC were predominantly in the Guanzhong Plain. ③ For the Loess Plateau region, greater vegetation recovery potential areas were detected in the northern area and the transitional area with the Guanzhong Plain, and the vegetation recovery potential was low in the Ziwuling forest area. Low vegetation recovery potentials were found in the Qinling-Bashan Mountain and Guanzhong Plain areas because of the high vegetation coverage background and the high rate of urbanization, respectively.[Conclusion] Shaanxi Province experienced significant FVC increases during 2000-2020 due to it being a key region of ecological project implementation. However, the heterogeneous spatial-temporal variation of FVC was affected by climate, topography, plant species, and human activities. The growth rate of vegetation restoration in Shaanxi Province tended to slow down, the continuous improvement ability has been lower, and the vegetation cover tended to be stable. However, the northwest region of the Loess Plateau and its border with Guanzhong Plain still has a large potential for vegetation cover restoration.

Abstract:[Objective] Soil erosion is an important environmental problem of globality, which seriously restricts human production and life. Soil maintenance conservation founction was quantitative studied to formulate the regional soil and water conservation measures, and provide scientific basis for the functional partition planning and governance of Harbin City.[Methods] Based on the InVEST model sediment delivery ratio module, this study evaluated the soil erosion and soil conservation in 2000, 2010 and 2020 in Harbin, analyzed the spatial aggregation type of soil conservation with the help of spatial autocorrelation, and used the optimal geographic detector to reveal the driving forces of spatial heterogeneity.[Results] ① In 2000, 2010 and 2020, the soil conservation in Harbin City was 2.18×10⁹, 2.07×10⁹, and 2.77×10⁹ t, respectively, showing a trend of decreasing first and then increasing, and the overall spatial distribution pattern of "low in the west and high in the east". ② The soil conservation amount showed a strong spatial positive correlation, mainly "low-low aggregation" and "high-high aggregation" types, the "low-low aggregation" type area showed a downward trend, while the "high-high aggregation" type showed a decreasing and then rising trend. ③ Elevation, precipitation and slope had the strongest explanatory power on the spatial heterogeneity of soil conservation in Harbin City, with average explanatory forces of 0.225 9, 0.198 9 and 0.180 4, respectively, and the interaction between slope and precipitation and other factors was the strongest explanatory interaction factor in the study area.[Conclusion] Water and soil management in the western part of Harbin City and along the Songhua River should be strengthened, while good water and soil conditions in the north and east of the city should be maintained to avoid large-scale human disturbance activities.

Abstract:[Objective] An ecological compensation model taking into account regional background differences was established to further clarify the spatial and temporal differentiation pattern of ecological compensation and its leading driving factors in the Beijing-Tianjin-Hebei region, in order to provide to a reference for government departments to formulate environmental protection and macroeconomic policies.[Methods] Based on a modified carbon deficit, a reasonable ecological compensation framework was constructed using model construction, spatial correlation analysis, and GeoDetector technology, etc. The spatial and temporal variability pattern, spatial autocorrelation, driver ranking, and interaction of ecological compensation in the Beijing-Tianjin-Hebei region during the period of 2007 to 2020 were analyzed and investigated.[Results] ① Carbon emissions in the Beijing-Tianjin-Hebei region from 2007 to 2020 showed a pattern of "increasing and then decreasing" over time, and carbon sequestration generally showed a trend of continuous increase. ② The carbon deficit in the Beijing-Tianjin-Hebei region before the amendment showed a U-shaped pattern with high carbon deficits in the east, south, and west, and low carbon deficits in the north. After the amendment, the carbon deficits were higher in the east, south, and west due to low carbon deficits in the north. After the amendment, the carbon deficits were more evenly distributed in space and time due to the local differences between regions. ③ The cold spot area of the ecological compensation amount was basically located in the Northeast Beijing-Tianjin-Hebei region, and the hot spot area was located in the Southwest Beijing-Tianjin-Hebei region. There were individual cold and hot spot areas between the two areas. The hot spot area was moving to the northeast, while the cold spot area was moving towards the southwest. ④ The main factors affecting the change of ecological compensation amount were different in different years, and the main factors affecting the change of the ecological compensation amount were different. Compensation amount changed in different years. The main factors affecting the changes in ecological compensation in the Beijing-Tianjin-Hebei region in 2007, 2012, 2017, and 2020 were tertiary industry output, financial revenue, secondary industry output, and per capita gross domestic product, respectively. The interactive influence of the factors leading to the changes in ecological compensation was different in different years. The interaction effect showed the repeated effect of decreasing each other and then increasing each other. The interaction effect was different in different years.[Conclusion] The ecological compensation model that takes into account regional background differences has a certain fairness to the analysis of the spatio-temporal differentiation pattern of ecological compensation and its leading driving factors in the Beijing-Tianjin-Hebei region, and provides more accurate guidance and suggestions for government departments to formulate environmental protection and macroeconomic policies.

Abstract:[Objective] The change characteristics and dynamic evolution trend of carbon neutral effect in 30 provinces (municipalities and regions) in China from 2000 to 2020 were analyzed, and the characteristics and internal motivation mechanism of ecological environment in agriculture and rural area were quantitatively revealed, in order to provide theoretical basis for further promoting the process of "carbon neutral" in agriculture and rural areas of China.[Methods] Based on the perspective of large agricultural production systems, 37 types of carbon sources and 28 types of carbon sinks were selected by the emission coefficient method to calculate the carbon neutrality effect for agriculture and rural areas in 30 provinces (municipalities and regions) in China during 2000-2020. The spatial and temporal distribution characteristics of the carbon neutrality effect were determined, and its dynamic evolution characteristics were observed by the Kernel-Density method.[Results] ① The carbon neutral effect in China's agriculture and rural areas increased steadily over time, with an average annual increase of 2.79 %. The overall growth rate fluctuated, and the growth rate of carbon sinks was significantly faster than the growth rate of carbon emissions. ② The spatial imbalance of the carbon neutral effect in China's agriculture and rural areas increased significantly, showing a distribution pattern of "lower in the middle and higher in the periphery". The difference between provinces was obvious:the top 10 provinces (municipalities and regions) accounted for 66.42 % of the national carbon neutral effect, while the bottom 10 provinces (municipalities and regions) accounted for only 4.72 % of the national carbon neutrality effect. ③ The level of the carbon neutrality effect showed a distribution trend of "central region > eastern region > western region", and there were great differences between different regions. The planting industry was the largest source of emission reduction and sink increase. ④ The center of the carbon neutrality effect density function curve in China's agriculture and rural areas had shifted to the right as a whole, and the spatial gap between provinces (municipalities and regions) has gradually expanded. Unbalanced regional development was observed.[Conclusion] Low-carbon economy and modern agriculture are intertwined. All regions should formulate carbon neutral development plans in agriculture and rural areas according to local conditions, bring about an inter-regional carbon neutral coordination mechanism, and accelerate the process of carbon neutral in agriculture and in rural areas.

Abstract:[Objective] The carbon emission efficiency of grain production was determined for 74 cities in the five provinces of Huang-Huai-Hai region, and spatial differentiation and dynamic evolution were quantified in light of the "double carbon" goals development strategy and goals. The current situation of carbon emission efficiency of grain production in the five provinces of Huang-Huai-Hai region was analyzed in order to promote green and low-carbon grain production in the region.[Methods] The carbon emission coefficient method and the three-stage super-efficiency SBM model were used to measure carbon emissions and carbon emission efficiencies of grain production for 74 cities in the five provinces of Huang-Huai-Hai region from 2011 to 2020. The spatial differentiation and dynamic evolution of carbon emission efficiency of grain production were then determined by means of the Theil index and kernel density estimation.[Results] ① Carbon emissions of grain production in the five provinces and cities of Huang-Huai-Hai region during the study period showed a fluctuating downward trend with an "M" shape, but the decline was slow. The use of chemical fertilizers was the main cause of grain carbon emissions. ② The carbon emission efficiency of grain production in the five provinces and cities of Huang-Huai-Hai region initially decreased and then increased. The average efficiency of the first stage was 0.59. Excluding the influence of environmental variables and random errors on the efficiency value, the average efficiency of the third stage was 0.48, which was 18.6 % lower than the efficiency value of the first stage. Chuzhou, Zhumadian, Dezhou, and other cities had higher efficiency values, while Huangshan, Weihai, and other cities had lower efficiency values. ③ The spatial differences of the carbon emission efficiency of grain production was on the rise, and the differences within the region were the main factor affecting the overall difference, among which the difference between cities in Henan Province was the most significant. ④ During the sample investigation period, the core density curve changed from a "single-peak shape" to a "double-peak shape" where the main peak showed a fluctuating rise and a slight shift to the right, and the secondary peak maximum was smaller, indicating that the overall level of carbon emission efficiency of grain production in the five provinces of Huang-Huai-Hai region had increased, regional differences had increased, and the region showed a multi-polar trend.[Conclusion] The overall level of carbon emission efficiency of grain production in the five provinces of Huang-Huai-Hai region was low, and there were obvious spatial differentiation characteristics. In the future, all regions should reduce the input of materials such as chemical fertilizers, and adopt the strategy of "counterpart assistance" to promote the positive interaction of grain production technology in various regions so as to narrow regional differences in the carbon emission efficiency of grain production among regions.

Abstract:[Objective] The hydraulic characteristics and ¹³C isotopic characteristics of the non-uniform enrichment of light (LF_OC) and heavy (HF_OC) fractions of soil organic carbon in sediments during the sheet erosion process were determined in order to provide theoretical and technical support for a better understanding of the dynamic changes in soil organic carbon stocks under water erosion.[Methods] This study was conducted on Lou soil from Yangling District of Xianyang City, Shannxi Province. An improved "three-zone" mobile steel soil pan was used together with an artificial rainfall simulator to measure runoff hydraulic parameters, organic carbon compositions of each aggregate size in sediments, and their related δ¹³C values. Additionally, these results for Lou soil were verified based on the δ¹³C values of organic carbon in eroded sediments and runoff hydraulic parameters for brown soil.[Results] ① When rainfall intensity and slope were low, both LF_OC and HF_OC were enriched in eroded sediments, and the organic carbon composition of macroaggregates were observed to be more susceptible to the influence of rainfall intensity and slope than observed for clay and silt particles and microaggregates. ② The δ¹³C values of organic carbon in clay and silt particles were negatively correlated with the percentage of LF_OC in SOC (λ), while the δ¹³C values of organic carbon in other size aggregates showed a significant positive correlation with λ values (p<0.05). ③ Flow velocity was positively correlated with λ values of clay and silt particles (p<0.05), while Reynolds number was negatively correlated with δ¹³C values of clay and silt particles, microaggregates, and macroaggregates (p<0.01). Increasing flow velocity during sheet erosion promoted the preferential transport of clay and silt size organic carbon, while turbulence promoted the transport of organic carbon with low δ¹³C values in aggregates; ④ For clay and silt particles, the larger the flow velocity and Reynolds number, the smaller the δ¹³C value of organic carbon and the larger the λ were. For microaggregates and macroaggregates, the smaller of Reynolds number, the larger the δ¹³C values of organic carbon and λ values in microaggregates were.[Conclusion] The loss of LF_OC and HF_OC was closely related to flow velocity and Reynolds number during the sheet erosion process. The effectiveness of using the ¹³C isotope in tracing organic carbon in eroded sediments was verified.

Abstract:[Objective] The land use change and its impact on carbon storage was studied from 2005 to 2020, and the land use pattern and carbon storage in the Pearl River Delta in 2035 were simulated and predicted, in order to provide a scientific basis for the territorial spatial planning and ecological decision-making under the dual carbon goal in the Pearl River delta region.[Methods] Based on land use data for four periods from 2005 to 2020, land use change and carbon storage evolution in the Pearl River delta urban agglomeration were analyzed by using the PLUS model and the InVEST model. The spatial pattern of land use and the carbon storage change trend in 2035 were predicted.[Results] ①From 2005 to 2020, carbon stocks initially increased and then decreased. The increased area of forest land, construction land, and unused land increased carbon stocks by 4.82×10⁷ t, and the decreased area of cultivated land, grassland and water area decreased carbon stocks by 5.10×10⁷ t. ② In 2035, with an expected increase of construction land and forest land, carbon storage will increase by 5.75×10⁷ t compared with 2020, and the ecological environment will improve. ③ Carbon storage showed a spatial distribution pattern of "higher in the surrounding areas and lower in the middle" that was significantly consistent with the spatial distribution of land use, i.e., the high-value carbon storage areas were concentrated in forest land, cultivated land, and grassland, and the low-value carbon storage areas were concentrated in construction land.[Conclusion] With the needs of future urban development, government departments should carry out comprehensive land development and utilization, adopt ecological restoration measures based on biological and engineering technology, and improve regional carbon sequestration capacity so as to achieve carbon neutrality.

Abstract:[Objective] The carbon emission effect on changes of the productional-living-ecological functions was determined in order to provide a reference for territorial and spatial planning meeting the "dual carbon" goals of "carbon peak" and "carbon neutrality".[Methods] The evaluation assignment method, the energy consumption method, and a geographical weighted regression model were used to determine the spatial-temporal evolution characteristics of the productional-living-ecological functions and their effects on carbon emissions in Liaoning Province from 2005 to 2020.[Results] ① The spatial distribution pattern of the productional-living-ecological functions in Liaoning Province did not change much from 2005 to 2020. Most of the areas were dominated by productional and ecological functions, the living function areas expanded significantly, and the spatial differences mainly occurred between the central urban area and the surrounding areas. ② From 2005 to 2013, the carbon emissions of counties in Liaoning Province increased rapidly, and from 2013 to 2020, the growth rate was slower but its spatial differences became more obvious. The high carbon emissions were significantly concentrated in Shenyang and Dalian cities. ③ The overall correlations between the productional-living-ecological functions and carbon emissions were strong. The spatial differences were obvious and the influencing factors were complex.[Conclusion] Under the constraints of natural conditions and guided by their social and economic development needs, counties in Liaoning Province need to clearly define the main functions of the land and promote regional cooperation on the basis of their own advantages and resource endowments so as to realize carbon emission reductions over the entire region.

Abstract:[Objective] Changes in land use and carbon storage in Maowei Sea of Guangxi Zhuang Autonomous Region were analyzed in order to provide a scientific basis for increasing its carbon sink capacity and improving its ecological value.[Methods] The supervised classification method was used to interpret and extract remote sensing image data for Maowei Sea in 2009, 2015, and 2021. ArcGIS and the InVEST model were used to analyze spatiotemporal changes in land use and carbon storage in Maowei Sea.[Results] ① The land use types in Maowei Sea mainly showed the distribution characteristics of "large settlement, small mixed residence". The areas of cultivated land, shallow sea waters, and fishery breeding areas decreased, and the areas of mangrove wetlands, building land, forest grassland, and silty tidal flats increased from 2009 to 2021. ② Carbon storage initially decreased and then increased over time. Changes in net carbon sequestration and its net present value in Maowei Sea were, respectively, -1.10×10⁵ tons and -1.37×10⁸ yuan, 3.77×10⁴ tons and 4.66×10⁷ yuan, and -7.29×10⁴ tons and -9.01×10⁷ yuan in 2009-2015, 2015-2021 and 2009-2021. ③ The conversion from high carbon sequestration land use types (fishery breeding areas and forest and grasslands) to low carbon sequestration land use types (building land) in Maowei Sea in 2009-2021 caused the largest carbon storage loss, reaching 2.85×10⁵ t. The conversion to fishery breeding areas increased carbon storage by 1.81×10⁵ t.[Conclusion] Accelerating the conversion and upgrading of farming methods, increasing the proliferation of mangrove forests in terrestrial and aquatic forested areas, and accelerating the construction of forest cities will promote carbon sequestration and sustainable development in Maowei Sea.

Abstract:[Objective] The impacts of land use/cover changes on carbon storage and ecosystem vulnerability in regional ecosystems were determined in order to provide a reference for regional green low-carbon and sustainable development of ecosystems.[Methods] The ecosystem carbon storage and its spatial distribution pattern were quantitatively analyzed by using land use/cover data for the core economic zone of the Central Guizhou urban agglomeration in 2000, 2010, and 2020 with the InVEST model and a land use transfer matrix. A potential impact index (PI) was used to assess the vulnerability of regional ecosystem services.[Results] ① Land use/cover changes in the core economic zone of the Central Guizhou urban agglomeration showed that cultivated land and forest land continued to decline from 2000 to 2020, and construction land continued to increase. Land use/cover changes in the study area were mainly manifested as the transfer of cultivated land, forest land, and grassland to other land use types, among which 3 339.35 and 3 669.15 km² of land were transferred from 2000 to 2010 and 2010 to 2020, respectively. The conversion of forest land to grassland was the main transfer type during the first period, and the conversion of arable land to construction land was the main transfer type in the second period. ② Regional carbon storage decreased from 2000 to 2020 (from 4.42×10⁷ to 4.33×10⁷ t), with a cumulative decrease of 9.40×10⁵ t. The conversion of forest land to grassland was the main reason for the reduction in carbon storage. The carbon storage density in each year was higher in the west and east, and lower in the middle portion of the study area. There was no significant change in the high density area during the past 20 years, while the low density area spreading from the central area to the periphery. ③ The core economic zone of the Central Guizhou urban agglomeration was the main source of carbon from 2000 to 2020, with the land use degree index increasing by 2.83, and PI index being -0.04 and -0.31, respectively, showing negative potential impact and increasing vulnerability.[Conclusion] Increasing forest land, controlling forest land conversion to other uses, and expanding construction land are important means for promoting regional green, low-carbon, stable, and sustainable development of ecosystems.

Abstract:[Objective] The changes in blue-green space land use were predicted and their impacts on carbon storage in Daxing'an Mountains were analyzed in order provide scientific strategic for realizing the "dual-carbon" goal guidance references.[Methods] Based on land utilization data for Daxing'an Mountains in 2015 and 2020, the driving factors of a binary logistic regression test were introduced into the PLUS model to predict the blue-green space land utilization pattern in 2030. The InVEST model was coupled with the results to analyze the impact of changes in blue-green space on carbon storage. The main driving land types of blue-green space causing changes in carbon storage were quantified and verified.[Results] ① Blue-green space continued to grow from 2015 to 2030. Forest land increased over this time period, accounting for more than 60 % of the blue-green space transfer, indicating that forest land held an absolute advantage. ② From 2015 to 2020, blue-green space accounted for 96.52 % of the total area of carbon storage growth space. Carbon storage for the natural development, blue-green space protection, and rapid urban development scenarios in 2030 were 1.459 4×10⁹ t, 1.483 1×10⁹ t, and 1.464 7×10⁹ t, respectively, mainly due to the transfer of a large amount of non-blue-green space to forest land and grassland. Protection of blue-green spaces had the most obvious effect on the increase of carbon storage. ③ The degree of aggregation of forest land, grassland, and water areas in the blue-green space was significantly and positively correlated with carbon storage. Forest land and grassland were the first and second most dominant types of carbon storage changes.[Conclusion] Excellent ecological policies should be promoted in the future to protect the blue-green space and to improve the structural integrity of forest land and grassland so as to achieve the "dual-carbon" strategic goal in the Daxing'an Mountaions.

Abstract:[Objective] The influence of land use change patterns on the spatial distribution of carbon sinks for the Inner Mongolia section of the Yellow River basin was investigated, and the main driving factors behind the spatial distribution of carbon sinks were identified in order to provide a basis for directing ecological spatial development and for developing sink enhancement policies in the study area.[Methods] The study was conducted for the Inner Mongolia section of the Yellow River basin. InVEST-FLUS model was used to analyze changes in the carbon sink capacity during each period of the study based on land use data from 2000, 2010, and 2020. The patterns of carbon stock changes were simulated in 2040 under three different scenarios (natural development, ecological conservation and agricultural priority), and identified the main driving factors behind the differences in the spatial distribution of carbon sinks with the help of geographic probes.[Results] ① From 2000 to 2020, carbon storage for the Mongolia section of the Yellow River basin initially increased and then decreased, with an overall increase of 8.63×10⁶ t. Subsurface biological carbon storage increased by 3.91×10⁶ t and soil carbon storage increased by 2.28×10⁶ t. ② Carbon storage continued to decrease by 3.92×10⁶ t for the future natural development scenario, but increased by 2.21×10⁷ t for the ecological protection scenario, which was higher than for the agricultural priority scenario (4.99×10⁶ t). Soil carbon storage was the key factor causing the incremental difference. ③ The unbalanced distributions of mean annual rainfall and mean annual temperature were the main factors causing differences in the various carbon pools for the Mongolia section of the Yellow River basin.[Conclusion] Reasonable ecological protection policies are more in line with the future requirements of urban intensification and ecological high-quality development. Future attention should be given to preventing and controlling desertification, and to promoting forest and grassland construction so as to improve the regional ecological security pattern and carbon sink enhancement policies.