The Horqin Sandy Land is a typical area of land desertification evolution in the semi-arid grassland region of northern China. It is a core area for national efforts to control desertification and studying the terrestrial ecosystem's carbon cycle in response to global changes. The Naiman Desertification Research Station， located in the southwestern part of the Horqin Sandy Land and established by the Chinese Academy of Sciences， is a long-term observation and research platform. It is dedicated to preventing and controlling land desertification in the northern agro-pastoral transition zone. This paper reviews four decades of the station's research on carbon cycling in the Horqin Sandy Land， with a focus on the following four areas： ①the carbon content and storage dynamics in the plant-soil systems， ②the soil respiration characteristics， ③the ecosystem carbon flux evolution， and ④the carbon sequestration effects of ecological restoration. This research reveals changes in vegetation and soil carbon pools during both desertification progression and reversal， clarifies the spatiotemporal patterns of regional-scale soil organic carbon and its driving mechanisms， and determines the response thresholds of soil respiration to temperature and moisture alongside shifts in the contribution ratios of its components across different habitats. It also identifies the dominant factors controlling the variability of the carbon sink function in diverse ecosystems over time， based on long-term flux observations， and quantifies the carbon sequestration rates and potential of various ecological restoration measures， elucidating their underlying mechanisms. These findings are profoundly significant in deepening our understanding of the pathways， processes， and mechanisms involved in carbon sequestration and sink enhancement through ecological restoration in semi-arid sandy regions. They also provide crucial scientific support and practical guidance for the precise implementation of China's dual-carbon strategy （carbon peaking and carbon neutrality） in ecologically fragile areas.

Understanding the spatial pattern of soil and microbial carbon， nitrogen and phosphorus （C∶N∶P） stoichiometry and its drivers are important for regulating ecosystem function and responding to global climate change. In this study， we applied geostatistical methods and constructed a random forest model to quantify the drivers of the spatial distribution of soil and microbial C∶N∶P stoichiometry in the Horqin Sandy Land through a regional field survey. The results showed that low-value zones for soil microbial carbon （MBC）， nitrogen （MBN） and phosphorus （MBP） were primarily located in the central part of the Horqin Sandy Land. In contrast， high-value zones were mainly found in the northern part of the Horqin Sandy Land， specifically in the foothills of the Greater Khingan Mountains. The ratios of MBC∶MBP and MBN∶MBP gradually increased from south to north. In the Horqin Sandy Land， the MBC∶MBN ratio ranged from 0.63 to 28.29 （average： 7.3）， the MBC∶MBP ratio from 0.35 to 91.27 （average： 11.26）， and the MBN∶MBP ratio from 0.07 to 10.16 （average： 1.56）. These values were all lower than the global and Chinese stoichiometric ratios. Overall， the region exhibited limitations in C， N and P， with MBC and MBN content primarily influencing the spatial variation of soil microbial biomass C∶N∶P in the Horqin Sandy Land.

Naiman Banner， a crucial grain production base in the semi-arid agro-pastoral ecotone of northern China， has been facing increasingly severe water resource shortages. With continuous expansion of agricultural land， the groundwater depth in this region has shown a persistent increasing trend. Based on long-term monitoring data from 25 groundwater observation wells， this study divided the study area into three subregions： Zone I （northern farmland）， Zone II （central sandy area）， and Zone III （southern mountainous area）， according to land use and elevation characteristics. The spatiotemporal evolution of groundwater depth from 1985 to 2020 was analyzed using the Kriging interpolation method. The results indicate that： （1） Groundwater depth exhibited an overall increasing trend， with a temporary rise during 1995-1999 due to increased precipitation. （2） Seasonal variations in groundwater depth differed among subregions due to distinct dynamic patterns. Interannually， Zone I showed the fastest annual increase （0.22 m）， significantly higher than Zone II and Zone III （both 0.09 m）， with Daqintala Town experiencing the most pronounced rise. （3） Land use conversion among cropland， grassland， bare land， and built-up areas was most significant， particularly cropland expansion in Zone I and urban development in Zone II， which exerted decisive impacts on groundwater depth changes. （4） Before 2000， meteorological factors dominated groundwater depth variations across all subregions， whereas after 2000， interactions between irrigation area and other driving factors intensified in Zone I， while Zone II remained primarily influenced by temperature and evaporation， and Zone III showed increasing interactions between precipitation and irrigation area. This study provides a scientific basis for understanding groundwater dynamics in Naiman Banner and offers critical insights for regional water resource management and sustainable development.

The Horqin Sandy Land suffers from severe land desertification. Research into the spatiotemporal evolution patterns of the wind erosion prevention and sand fixation service holds significant importance for regional ecological security and sustainable development. This study systematically analyzed the spatiotemporal dynamics， driving mechanisms of wind erosion prevention and sand fixation service in the Horqin Sandy Land from 2000 to 2020 using the Revised Wind Erosion Equation （RWEQ） model， the XGBoost-SHAP algorithm， and HYSPLIT trajectory simulations. The results indicate： （1） The wind erosion prevention and sand fixation service exhibited significant spatiotemporal heterogeneity. The sand fixation per unit area showed a trend of initial decrease followed by increase， with a spatial pattern characterized by a higher in the central-southern regions and lower in the northern areas. （2） The XGBoost-SHAP model quantified vegetation coverage as the core driving factor， while interactions among wind days， precipitation， and temperature nonlinearly influenced wind erosion processes. （3） HYSPLIT simulations identified 3 559 sand transport trajectories over the 20-year period， with an overall decline in trajectory frequency， indicating enhanced sand fixation capacity. Cluster analysis revealed four dominant pathways： 31.67% of trajectories moved eastward into the Pacific Ocean， 29.92% influenced northeastern regions （Jilin and Heilongjiang）， 20.46% crossed borders to areas such as North Korea and Japan， and 17.95% migrated southward to China’s southeastern coast. These findings provide a scientific basis for optimizing desertification control strategies and coordinating regional ecological compensation mechanisms， while offering methodological references for studying ecosystem service flows in arid and semi-arid regions.

With the clear proposal and in-depth implementation of the national strategic goal of carbon neutrality and carbon peak， China's desertification areas have ushered in the climax of photovoltaic power plant construction. This initiative not only promotes the development of green energy， but also has a series of complex and far-reaching impacts on the natural environment in the desert area. This paper aims to comprehensively sort out the specific impact of photovoltaic power plant construction on desert ecological environment， and summarize the typical problems and challenges existing in the current model through in-depth analysis of the practical cases of "photovoltaic + ecological governance" model adopted by photovoltaic power plants in some deserts at home and abroad. On this basis， this paper puts forward a series of improvement suggestions and strategies， aiming at providing scientific and systematic guidance for the current and future ecological management work of photovoltaic power stations in desert areas， and providing strong scientific and technological support and theoretical basis for promoting ecological restoration and sustainable development of desertification areas.

Studying the characteristics of land use change and exploring pathways for its rational utilization are of great significance for regional sustainable development. Taking the changes in farmland area of the Horqin Sandy Land as an entry point， this paper reviews the historical evolution and current status of farmland area in this region， focusing on the impacts of farmland area changes on regional groundwater and farmland wind erosion. Effective approaches and methods for controlling farmland dust sources are proposed. It is recommended that farmland management in the Horqin Sandy Land include： enhancing the monitor and early warning systems for farmland in dust source areas； strengthening the construction of farmland windbreak systems through comprehensive development and management of shelterbelts to fully leverage their critical windbreak functions； reducing wind erosion and enhancing soil conservation capacity by implementing conservation tillage and winter cover cropping； improving integrated management of soil moisture and nutrients by vigorously promoting water-saving irrigation techniques and soil organic fertilization measures to achieve efficient utilization of water-fertilizer resources and comprehensive enhancement of soil quality. Implement classified treatment and adjusted management for different rainfed and irrigated farmlands to enhance comprehensive governance efficiency.

Vegetation constitutes a critical nexus among the atmosphere， soil， water， and biosphere. Investigating its spatiotemporal dynamics and driving mechanisms is critical for understanding ecosystem evolution. This study leverages 22-year MOD13Q1 NDVI remote sensing data （2000-2022） and integrates natural factors （digital elevation models， soil types， precipitation， temperature， evapotranspiration） and socioeconomic parameters （land use types， population， GDP）. Analytical techniques including pixel binning models， trend analysis， and geographic detectors were applied to systematically evaluate vegetation coverage patterns and their drivers in the Kubuqi Desert. Results demonstrate a sustained upward trend in vegetation coverage， with an annual growth rate of 0.387% （R²≈0.832）. Seasonal variations reveal peak coverage during June-August and minimal levels in November-January. Notably， 73.62% of the study area exhibited vegetation improvement： the desert core transitioned from extremely low to low coverage grades， the southwest shifted from low-medium to medium-high grades， and the southeast achieved widespread high-grade coverage. Single-factor analysis identified land use types （0.493）， precipitation （0.461）， and population density （0.443） as dominant individual drivers. Multi-factor interaction detection highlights precipitation-elevation synergy （interaction q=0.731） as the most significant combined influence on vegetation dynamics.

The potential of carbon sequestration in typical sandy regions of China has long been overlooked，with a lack of systematic analysis over long time series and quantitative assessments of the driving mechanisms of climate change and human activities. In this study，we employed the CASA and Thornthwaite Memorial models to analyze the spatiotemporal variations in net ecosystem productivity （NEP） across typical sandy areas，including the Mu Us Sandy Land，the Hunshandake Sandy Land，the Horqin Sandy Land，the Hulun Buir Sandy Land，and the Songnen Sandy Land，from 1982 to 2024. We also explored the driving mechanisms of meteorological and human factors on the evolution of NEP. The results show that，by 2024，the average annual NEP of the typical sandy regions was 166.67 g·m^-2·a^-1，with significant spatial differentiation. The carbon sequestration capacity in the eastern regions was notably higher than in the western regions. Among these areas，the Songnen Sandy Land exhibited the strongest carbon sequestration capacity，with an annual NEP of 211.08 g·m^-2·a^-1，while the Mu Us Sandy Land had a weaker carbon sequestration capacity，with an annual NEP of only 122.68 g·m^-2·a^-1. From 1982 to 2024，the overall NEP of these regions showed a decline followed by a recovery，reaching a minimum of 130.68 g·m^-2·a^-1 in 2000 and subsequently rising to 166.67 g·m^-2·a^-1 by 2024. In terms of spatial changes，the areas with increased carbon sequestration accounted for 59.96% （10.03×10⁴ km²） of the total study area，with significant increases covering 57.79% （96 682.67 km²），primarily distributed in the Hulun Buir Sandy Land and the Songnen Sandy Land. In contrast，areas with significant decreases accounted for 35.85% （59 977.05 km²），mostly in the Mu Us Sandy Land and the Hunshandake Sandy Land. Human activities were the dominant factor contributing to the improvement of carbon sequestration，with a relative contribution rate of 49.33%. This study provides scientific evidence for carbon neutrality and ecological conservation in sandy regions.

The Beijing-Tianjin Sandstorm Source Control Project area （BTSSCPA） serves as a crucial ecological barrier in northern China， which has long been subjected to ecological pressures including sandstorms， desertification， and vegetation degradation. There is an urgent need to conduct scientific assessments of the spatiotemporal evolution patterns and driving mechanisms of ecological environment quality in the BTSSCPA. This study monitored and analyzed the ecological environment quality in the BTSSCPA based on the remote sensing ecological index （RSEI）. Leveraging the Google Earth Engine （GEE） platform， we constructed four indicators-heat， greenness， wetness， and dryness-using MODIS datasets to characterize the spatiotemporal patterns of ecological environment quality from 2000 to 2020. The Optimal Parameters-based Geographical Detector （OPGD） was employed to identify key influencing factors. Results were showed on the following： （1） The ecological environment quality of the BTSSCPA demonstrated a significant upward trend from 2000 to 2020. Analysis of ecological environment quality grading revealed a notable reduction in areas classified as "poor" and "relatively poor"， accompanied by a simultaneous expansion of regions categorized as "moderate"， "good"， and "excellent". Distinct spatial heterogeneity was observed in environmental quality distribution， manifesting a clear geographical pattern： superior ecological conditions predominated in southeastern sectors， while northwestern regions exhibited comparatively inferior environmental status. （2） Different factors， classification methods （e.g.， natural breaks vs. quantile） and the number of classification strata critically impacted the explanatory power of ecological environment quality assessments. （3） The influence of factors varied substantially， with annual precipitation and vegetation net primary productivity （NPP） demonstrating the most significant effects on ecological environment quality.

During the large-scale construction of photovoltaic （PV） power stations in desert regions， the areas beneath the panels often experience secondary wind erosion and sand accumulation due to ground surface disturbance and altered wind flow patterns. These issues seriously threaten ecological recovery and the safety of operational maintenance. To evaluate the windbreak and sand-stabilizing effects of different types of mechanical sand barriers in PV fields， this study selected three typical sand barriers， straw checkerboard， degradable polylactic acid （PLA）， and high-density polyethylene （mesh）， within a PV power station located in the Hobq Desert as the experimental site. The wind speed profile near the surface， surface roughness， and friction velocity under varying wind conditions were analyzed to systematically examine the influence of sand barrier type on wind speed modulation and surface stability. The results indicated that： （1） All three types of sand barriers significantly reduced wind speed within the 0-20 cm near-surface layer， with the mesh barrier showing the highest wind reduction efficiency up to 50% at the 10 cm height. （2） The installation of sand barriers markedly increased surface roughness and enhanced wind speed shear resistance， with the straw checkerboard demonstrating particularly notable effects. （3） All sand barriers effectively increased the friction velocity， with an average improvement ranging from 30% to 68% under wind speeds between 7.85 m·s^-1 and 12.03 m·s^-1. （4） Implementing sand barrier measures in the 200 MW PV power station reduced the average annual power generation loss rate to 2.9%. Furthermore， the annual panel cleaning costs were reduced by an average of ¥97 300 with the installation of the three types of sand barriers. Economic evaluation revealed that straw checkerboard barriers offer advantages such as low cost and wide material availability， whereas mesh barriers combine high wind reduction efficiency with durability. PLA barriers exhibited exceptional sand-fixing performance owing to their superior ground conformity. The findings provide a theoretical basis and technical support for controlling secondary wind-sand hazards in PV power stations situated in sandy areas.

The middle reaches of the Yellow River Basin are an important economic core area and growth pole in China. However， the safe boundaries for the sustainable development of key elements of its nature-social system remain unclear. The application of the Safe and Just Operating Space （SJOS） theory is expected to provide a novel assessment perspective for the sustainable development of this region. This study is based on the SJOS theory， taking the four provinces and autonomous region in the middle reaches of the Yellow River Basin （Inner Mongolia Autonomous Region， Shaanxi Province， Shanxi Province， and Henan Province） as the research objects. Using environmental monitoring and socio-economic data available from 1990 to 2023， an indicator system for measuring the natural social systems in the region was constructed to assess the SJOS for sustainable development in the study area. The grey prediction model was used to judge its development trend. The results showed that the SJOS of the four provinces and autonomous region in the middle reaches of the Yellow River Basin showed an overall positive trend in time series， and the current ranking of sustainability in the four provinces and autonomous region from best to worst is： Inner Mongolia Autonomous Region>Shanxi Province>Shaanxi Province>Henan Province. However， currently there are still 29 indicators in the four provinces and autonomous region that have exceeded the threshold. The correlation analysis and prediction results show that there are a total of 6 key factors affecting SJOS in the region. Two natural systems， namely fertilizer usage and freshwater utilization； Four social systems， namely industrial innovation， gender equality， sustainable cities， and decent work and economic growth. In short， the natural-social systems in the middle reaches of the Yellow River Basin are currently facing many challenges， but it still has great potential for sustainable development.

Enclosure is an important way to restore desertified grasslands， which has a significant impact on the structure and function of plant communities. Through the time-space substitution method， the plant communities after 22 and 41 years of enclosure of severely desertified grassland for natural recovery in Horqin Sandy Land were studied， to explore the driving mechanisms of long-term enclosure on vegetation restoration in severely desertified grasslands. The results showed that： （1） Compared with mobile sand dunes （severe desertification and the beginning of restoration）， long-term enclosure significantly increased vegetation coverage， height， and aboveground biomass， while vegetation density increased first and then decreased. （2） With the increasing enclosure years， the plant community evolved from annual grasses （with an important value of 0.75 after 22 years of enclosure） dominated by Setaria viridis to perennial herbaceous plants （with an important value of 0.78 after 41 years of enclosure） dominated by Pennisetum centrasiaticuma， Artemisia scoparia， etc. （3） With the increasing enclosure years， species diversity significantly increased and co-occurrence network relationships become more complex （with average degree increased from 1.47 to 1.60）. （4） Soil chemical and physical properties explained 55.5% of the variation in plant communities. Among them， soil organic carbon， bulk density， and soil moisture content， are the main driving factors. Although enclosure is an effective measure for vegetation restoration in severely desertified grasslands， the community structure， dominant species composition， and species co-occurrence network relationships after 41 years of enclosure differed significantly from sparse forest grasslands （reference for climatic climax community）. The results can provide data support and theoretical basis for the development of adaptive management strategies for vegetation restoration in desertified grasslands.

We conducted a comprehensive analysis of the litter decomposition characteristics of 6 dominant plant species and their impacts on soil microbial community structure in the Horqin Sandy Land. We used field-based litter decomposition experiments and microbial high-throughput sequencing technology. The results indicated that the decomposition rate of litter followed the order： Chenopodium acuminatum>Caragana microphylla>Setarria viridis>Artemisia halodendron>Cleistogenes squarrosa>Lespedeza bicolor. The initial nitrogen （N） content， lignin content， C∶N ratio， and lignin∶N ratio of the litter were identified as the critical factors influencing the rate of decomposition. After 15 months of decomposition， Actinobacteria， Proteobacteria， Chloroflexi， and Acidobacteria emerged as the predominant phyla within the bacterial community， while Ascomycota dominated the fungal community. The species diversity and richness of the bacterial community increased significantly， whereas the species diversity of the fungal community decreased markedly. The richness of the fungal community was positively correlated with the initial litter C∶N and lignin∶N ratios， but negatively correlated with the initial N content. Furthermore， the relative abundances of Actinobacteria， and Acidobacteria in the bacterial community， as well as Basidiomycota， Mucormycota， and Zoopagomycota， in the fungal community， were positively associated with the initial cellulose and hemicellulose contents， C∶N ratio， and lignin∶N ratio of the litter.

Plant adaptability refers to the characteristics optimization and survival ability nourishment of plants on multiple spatial-temporal scales through the processes of water and nutrient elements acquisition， regulation， growth and function maintenance. The sandy land plants in northern China have the characteristics of cold， drought and salt tolerance， wind and sand process resistance， and photophily， which are major basis for species selection， density allocation and management of biological control of desertification， and the theoretical basis for vegetation restoration and land degradation control in sandy land. However， studies on the relationship between sediment， plant water consumption， groundwater depth change and plant community on sandy dune land need to be further strengthened. The results show that the sediment depth of the Horqin Sandy Land gradually increases along the rivers west-eastwards from the mountain to the plain， and the depth of the sandy land in the middle part of the Horqin Sandy Land is the largest， about 200 m. There were significant differences in plant community characteristics among different types of dunes， and the changes in plant composition of mobile dunes were the most obvious. With the increase of land use pressure， groundwater depth increased， which affected the distribution pattern and composition characteristics of plants in Horqin sandy land. Dune fluctuation affects the relationship between plants and groundwater depth change.Water consumption of main plants in sandy land is between 300 mm and 450 mm， which is close to the average annual precipitation. Based on the water consumption of plants and the results of field investigation， the reasonable afforestation density in Horqin Sandy Land was between 225-375 plants per hectare. The restoration rate of desertified land in Horqin Sandy Land has entered a bottleneck period. After 1987， the effect of desertification control was not obvious. This study can provide scientific reference for the protection， control and utilization of desertified land in Horqin Sandy Land and the regions alike.

The indicator system of residents' well-being in the Yellow River Basin was constructed based on the human needs theory in this paper， and then the spatio-temporal pattern of residents' well-being in 2000-2023 was analyzed. The spatial relationship between the demand dimension of residents'well-being was explored through coupling coordination degree and relative development degree. Meanwhile， the influencing factors of coupling coordination of demand dimension and residents' well-being were revealed based on geographical detectors. Finally， we summarized the driving mechanism of the spatial and temporal pattern of residents' well-being. The conclusion as follows： （1） During the study period， the growth of basic demand in the Yellow River Basin was slow， and the change of spatial distribution was stable. The development of the remaining dimensions of well-being improved significantly，and the level of demand reached a higher state by the end of the study in most regions. The residents' well-being index in each region continues to rise and the growth rate was different， and the residents' well-being varies greatly among regions. （2） During the study period， the coupling coordination degree of sub-demand in the Yellow River Basin gradually improved. Most regions evolve from low coupling and low coupling to high coupling and high coupling.The whole basin has achieved a high level of well-being development. （3） The temporal and spatial differences of residents' well-being are the result of multiple factors. The main body initiative and government initiative had strong explanatory power to the temporal and spatial differences of residents' well-being，and they were the leading influencing factors. The explanatory power of geographical location and new tourism demand was medium， while the explanatory power of natural background was relatively weak.

This study explores the impact of the digital economy on the transformation and upgrading of the industrial structure in the Yellow River Basin. Using panel data from 118 prefecture-level cities in China's Yellow River Basin from 2000 to 2022， we empirically examine the effects of the digital economy on the transformation and upgrading of the region’s industrial structure， based on an analysis of the spatial evolution characteristics of the digital economy. Our findings indicate that the digital economy exerts a significant positive impact on the overall transformation and upgrading of the industrial structure in the Yellow River Basin， particularly on industrial upgrading， thus contributing effectively to the region's industrial advancement. However， the digital economy does not show a significant effect on the rationalization of the industrial structure， nor does it significantly influence the structural transformation. The mediation effect analysis suggests that the digital economy promotes the overall upgrading of the industrial structure in the Yellow River Basin through the improvement of the consumption structure and the enhancement of technological innovation. The results of the moderation effect test reveal that environmental regulation negatively moderates the overall transformation and upgrading process of the digital economy and industrial structure. The heterogeneity analysis further demonstrates that the effect of the digital economy on the transformation and upgrading of the industrial structure is more pronounced in regions with advanced digital economic development. Finally， the economic consequence analysis reveals that the digital economy has significantly enhanced the green economic efficiency of the Yellow River Basin， following the transformation and upgrading of its industrial structure. These findings not only enrich the literature on the digital economy and its economic implications but also provide theoretical insights and policy recommendations for regional industrial transformation and high-quality development.

As a major ecologically fragile area， the landscape pattern changes in the typical dune alternated with meadow area in Horqin sand directly reflect the interaction between human activities and climate change. Based on the 2000-2020 land use dataset， this study extracted and analyzed the spatial and temporal dynamic characteristics and driving factors of the landscape pattern in the study area from 2000 to 2020， using rainfall， evapotranspiration， soil moisture， Water body area and population size as the driving factors， and using the ArcGIS and Fragstats software. The results show that grassland， unused or other land and cropland were the main landscape types（>93%）in the interspersed areas of dune alternated with meadow area in Horqin sand， the area of grassland and water area gradually decrease， landscape fragmentation increases， connectivity decreases， shape is relatively complex， and landscape heterogeneity shows a decreasing trend. climate change can change the spatial configuration of vegetation cover in the study area， which can lead to the transition of sandy landscapes from a continuous matrix to a fragmentation pattern； and demographic changes can increase the richness of landscape types through land-use diversification. Therefore， climate change and population change can jointly drive the transformation of the landscape pattern， clarify the spatial and temporal differences in the study area， optimize the landscape pattern， and provide technical support for the ecological strategy of sand control and prevention in the region.

The changes in landscape patterns in the Loess Plateau gully region reflect the variations in regional ecological functions and processes. Their spatial differentiation reveals the spatial disparities in landscape processes and their driving forces， aiding in the spatial understanding of the dynamic changes and characteristics of regional landscape patterns. Taking Qingyang City， Gansu Province， as an example， this study systematically analyzed the spatiotemporal dynamics of regional land use changes and landscape patterns， as well as their ecological responses， based on land use data from 2000 to 2020， using ArcGIS and Fragstats software. The aim was to uncover the spatial differentiation characteristics of land use and landscape pattern changes in a typical Loess Plateau gully region. The results indicate： （1） From 2000 to 2020， the land use structure in the study area underwent significant transformations， showing an overall trend of "continuous decrease in cropland， initial increase followed by stabilization in forest and grassland， and expansion of construction land." The primary transitions of reduced cropland were to grassland， forest， and construction land. （2） The landscape pattern indices did not exhibit a clear temporal trend， but the study area displayed distinct spatial differentiation in landscape patterns. Specifically， patches in the northwestern region showed relatively higher ecological dominance， the central area exhibited greater fragmentation in patch size distribution， and the southeastern edge had relatively homogeneous landscape types with more regular patch shapes. （3） Changes in cropland and grassland areas correlated with landscape pattern indices， while gross domestic product（GDP） and total population were the main drivers of changes in landscape indices. This suggests that over time， the integration of ecological and socio-economic spaces in the study area has been deepening.

Promoting deep coordination between culture-tourism integration and ecological resilience in the Yellow River Basin is of great practical value to stimulate the kinetic energy of cultural and tourism industry， promote the construction of ecological civilization， and accelerate the basin to a new green path of sustainable development. This study takes nine provinces in the Yellow River Basin from 2011 to 2022 as the research object， and integrates the two composite systems of culture-tourism integration and ecological resilience into the same framework. On the basis of measuring the comprehensive level of the two systems， the Haken model is used to reveal the synergistic effect of the two systems and describe their spatio-temporal evolution. The main conclusions are as follows： （1） During the study period， the level of culture-tourism integration and ecological resilience in the Yellow River Basin was significantly improved， but the level of culture-tourism integration showed a "polarization" pattern， with obvious advantages of culture-tourism integration in the downstream region and prominent ecological resilience in the upstream region. （2） The integration of culture and tourism is the order parameter that dominates the collaborative evolution of the Yellow River Basin system. The overall collaborative level of the basin has an evolutionary trend of rapid improvement - stable operation， and the regional level presents a collaborative pattern of downstream > middle reaches > upstream. （3） The number of high-quality and medium synergistic provinces in the Yellow River Basin increased steadily， and the synergistic level showed a dynamic evolutionary pattern of "gradual decline from east to west" to "central catch-up" and then to "contiguous peak". （4） The public service supply of cultural tourism industry and ecosystem is the main obstacle in the early stage， and the negative impact of pollutant emission and ecological environment governance is gradually emerging. The upstream region needs to improve the basic input and performance output of cultural tourism， while the middle and downstream regions need to focus on the lack of ecological resilience supporting factors and ecological environment issues.

In order to understand soil bacterial community structure characteristics and potential ecological function changes of different afforestation restoration strategies in Hunshandake Sandy land. The enclosed sample plots of Pinus sylvestris， Populus， Salix gordejevii and Hedysarum leave were studied which have been planted in Hunshandak Sandy Land for 20 years. The mobile dune enclosed plots that have been restored naturally for 20 years were used as the control. Through the combination of 16S rRNA gene high-throughput sequencing， PICRUSt function prediction and soil nutrient content determination， the soil restoration of different vegetation restoration strategies in sandy land was investigated. The results showed that： （1） The relative abundances of Proteobacteria and Bacteroidota in the Hedysarum laeve forest were significantly increased by 41.16% and 52.94% respectively， compared with those in the Salix gordejevii forest. The relative abundances of Acidobacteria and Chloroflexi in the Salix gordejevii forest were significantly increased by 64.59% and 55.16% respectively， compared with those in the Hedysarum laeve forest. The relative abundance of Bradyrhizobium， Rhizobium and Mesorhizobium accounted for 3.59%， 0.97% and 0.80% in the Hedysarum laeve forest and 3.50%， 0.82% and 0.83% in the Populus forest， respectively. γ-proteobacteria were the marker bacteria of Pinus sylvestris forest. （2） Through PICRUSt function prediction， the abundance of genes involved in stress resistance was significantly increased. The abundance of membrane transport genes in Populus forest was significantly increased， the abundance of membrane transport and signal transduction genes in Hedysarum laeve forest were significantly increased. The abundance of genes involved in self-growth of Pinus sylvestris forest and Salix gordejevii forest were significantly increased. The abundance of amino acid metabolism and lipid metabolism genes was significantly increased in Pinus sylvestris forest. The abundance of gene in energy metabolism and carbohydrate metabolism of Salix gordejevii forest were significantly increased. These results indicated that the potential ecological function of the sand-fixing forest of Populus forest and Hedysarum laeve forest were more stable than that of Pinus sylvestris forest and Salix gordejevii forest. In conclusion， there were significant differences in soil bacterial communities in different vegetation restoration areas of Hunshandake Sandy Land， which led to different potential functions. Hedysarum laeve forest played an important role in nitrogen fixation and soil nitrogen accumulation in collaboration with soil nitrogen fixing bacteria compared with Pinus sylvestris forest， Populus forest and Salix gordejevii forest.

The northern arid regions of China， as a core area for global desertification control， have significant scientific importance and practical demand for exploring an efficient and stable sand control mode to advance the sustainable management of desertified land in arid areas. This study， focusing on the Horqin Sandy Land， constructs a composite system of two types of sand barriers （1 m×1 m crop straw sand barriers and 2 m×2 m shrub live sand barriers） and three vegetation establishment models （herbaceous monoculture， shrub monoculture， and herbaceous + shrub mixed planting）， and inoculates them with algal crusts， moss crusts， and mixed algal + moss crusts， aiming to clarify the impact of different sand control mode on the vegetation characteristics and the development of biological soil crusts in the Horqin Sandy Land. The results show that in 2022， there were no significant differences in plant height among herbaceous， shrub， and herbaceous + shrub planting methods under different types of sand barriers； however， in 2023， the average height of herbaceous communities significantly exceeded that of shrub and herbaceous + shrub mixed planting communities under no sand barrier， crop straw sand barrier， and shrub live sand barrier configurations. This indicates that the duration of vegetation restoration and the type of vegetation planting significantly affect community height. The vegetation coverage under each type of sand barrier control （bare sand） was about 10%， while the average coverage of herbaceous， shrub， and their mixed plantings reached over 50%. Further analysis revealed that the Shannon-Wiener index， Simpson's diversity index， and Pielou's evenness index of the herbaceous + shrub mixed planting treatment were significantly higher than those of the single planting treatments， indicating that compared to single-species communities， multi-species combinations can more effectively enhance ecosystem diversity. The root biomass of herbaceous， shrub， and herbaceous + shrub under crop straw sand barriers was significantly higher than that under no sand barrier and shrub live sand barriers， with the lowest underground biomass under shrub live sand barriers， possibly due to the competition for soil nutrients between shrub live bodies and planted vegetation， affecting the growth of plant roots. Therefore， in terms of sand barrier setting， crop straw sand barriers are relatively ideal types of sand barriers in the process of desertified land restoration. The addition of exogenous crusts in the control plots significantly increased the coverage of biological crusts， while all treatments had no significant effect on crust thickness. This study proposes a herbaceous + shrub mixed planting model based on 1 m×1 m crop straw sand barriers， supplemented with biological soil crust inoculation technology， which can provide an optimized plan for the short-term ecological restoration of the Horqin Sandy Land.

Understanding ecosystem service （ES） supply-demand relationships is crucial for scientifically evaluating human-ecosystem interdependencies and regional sustainability， thereby informing resource management and ecological conservation strategies. As a representative agro-pastoral ecotone in northern China， Horqin Sandy Land faces severe ecological challenges， yet comprehensive assessments of ES flows and human-earth system sustainability remain scarce. This study developed Ecosystem Service Supply （ESSI） and Human Demand （HMDI） indices to quantify ES evolution and spatial matching patterns （2000-2023）， evaluating sustainability through supply-demand balance diagnostics. Key findings reveal： （1） Grasslands contributed most significantly to ES provision， with supply services and regulation services stabilizing post-2005 after earlier fluctuations； （2） Spatially consistent patterns featured accelerated demand growth along functional zone peripheries， contrasting with declining internal supply； （3） Pronounced spatial mismatches emerged， particularly low-supply/high-demand zones （29%） concentrated in southern-eastern sectors； （4） Limited sustainability transitions occurred （2.55% significant degradation vs. 2.96% improvement）； （5） Synergistic areas dominated （79.94%）， characterized predominantly by negative synergies （concurrent ES-demand declines）， while trade-offs were minimized within functional zones.

The Liuyuan-Golmud Expressway is built in the Hexi Corridor and the inland extreme arid area of Qaidam Basin. Along the route， alpine wind-sand is the main environmental feature. Currently， there is limited research on the sand processes and prevention along the Liuyuan-Golmud Expressway. Therefore， through field observations and particle size analysis， this study investigated the wind-sand environment along the highway and found that the prevailing winds are from the northwest （NNW、WNW、W）， with frequency of sand-driving wind， sand transport potential， and maximal possible sand transport higher occurring in the summer months （May to July）. In contrast， these factors are lower in the winter months （November to January of the following year）. The sand transport direction along the highway primarily trends towards SE、SSE、ESE and E. From north to south along the highway， the surface sediment particles transition from fine sand to coarse sand， with the average particle size gradually becoming coarser. The particle distribution is relatively uniform， with fewer coarse particles.

Soil organic carbon （SOC） and nitrogen （N） are core elements for the functioning of soil systems. Investigating the effects of different plant communities and soil depths on SOC and total nitrogen （TN） is essential for understanding the variation patterns of soil carbon and nitrogen density in the Horqin Sandy Land. This study chose three plant communities in the Horqin Sandy Land： dominant species of Artemisia scoparia + Gramineae （ASP）， Caragana microphylla + Forbs （CMF）， and Agriophyllum squarrosum + Setaria viridis （ASGB） to investigate the characteristics of soil carbon and nitrogen density and their influencing factors. The results showed that： （1） In the 0-100 cm soil layer， SOC， TN， and total phosphorus （TP） followed the order： ASP community > CMF community > ASGB community. SOC and TN decreased with increasing soil depth， while TP and total potassium （TK） remained relatively stable. （2） The ASP community exhibited the highest soil stoichiometric ratios （C∶P， C∶K， N∶P， N∶K， P∶K）， whereas the ASGB community showed significantly higher C∶N in the 20-40 cm layer compared to ASP. Soil C∶P， C∶K， N∶K， and P∶K ratios generally decreased with depth. （3） Soil organic carbon density （SCD） and soil nitrogen density （SND） in the 0-10， 10-20 cm and 20-40 cm layers followed the order： ASP > CMF > ASGB. SCD in all three communities initially decreased and then increased with depth， while the ASP community displayed an opposite trend for SND. （4） The contribution rates of soil C∶N and clay to SCD were 15.5% and 11.7%， respectively； the contribution rates of soil N∶P， N∶K and clay to SND were 23.7%，22.3% and 8.4%， respectively.

The study of water resources and vegetation dynamics in groundwater-dependent ecosystems on the Mongolian Plateau is of great scientific significance for the sustainable utilization of water resources on the Mongolian Plateau. In this study， we used the Mongolian Plateau as the study area， calculated the changes of groundwater reserves on the Mongolian Plateau based on the GRACE gravity satellite， and analyzed the trends of groundwater reserves and their relationships with NDVI， precipitation， and evapotranspiration from 2002 to 2021 by using the Sen slope estimation， the M-K trend test， and Pearson's correlation coefficient calculation method. The results show that：（1） the groundwater storage in the Mongolian Plateau shows an overall decreasing trend in time， and the rate of decrease gradually accelerates； spatially， the groundwater storage in the north and the central part of the Plateau slightly decreases， while in the west and the south it decreases more， and the rate of change of the groundwater storage is -347.38 mm·a^-1， and the rate of decrease of the groundwater in Inner Mongolia is larger than that in Mongolia. （2） The changes in NDVI and groundwater reserves on the Mongolian Plateau are correlated. In the northern and southeastern parts of the Plateau， NDVI and groundwater reserves are negatively correlated， with a significant negative correlation accounting for only 1.39% of the total； in the central part of the Plateau， there is a positive correlation， with a significant positive correlation accounting for 9.33% of the total. （3） Precipitation and groundwater storage changes are correlated on the Mongolian Plateau. In the southwestern part of the Plateau， there is a positive correlation between precipitation and groundwater storage changes， with a significant positive correlation accounting for 5.41% of the area； in the eastern and northwestern parts of the Plateau， there is a negative correlation， with a significant negative correlation accounting for 3.36% of the area. （4） The evapotranspiration on the Mongolian Plateau is a key factor affecting the change of groundwater storage， and the evapotranspiration has a significant effect on the change of groundwater storage. In the northeast of the Mongolian Plateau， the significant positive correlation accounts for 2.87% of the area， and the negative correlation between the northwest and the southeast， and the significant negative correlation accounts for 3.95% of the area. In the future， the area covered by vegetation in Mongolia should be increased and the rate of vegetation increase in Inner Mongolia should be reduced moderately. The study reveals the spatial and temporal variations of groundwater storage on the Mongolian Plateau， and its correlation with the influencing factors. It provides data support for ecological restoration of the Mongolian Plateau.

Horqin Sandy Land is one of the four great sandy lands in northern China. Due to the relatively high level of precipitation and temperature conditions and the unique characteristics of civilization evolution， nomadic and farming civilization alternate development of history. In modern times， the rapid development of agricultural and husbandry production activities derived from the social change and population surge led to the continuous land degradation of Horqin Sandy Land in the past hundred years. The resulting phenomena such as low vegetation coverage and increased wind and sand activities， on the one hand， limit the development of regional agricultural and husbandry economy and the improvement of the living standards of farmers and herdsmen， on the other hand， lead to the deterioration of environmental quality， thus contradicting the demand for high-quality life. Under this background， the state and local governments have implemented a series of major projects， policies and regulations related to ecological restoration in Horqin Sandy land， and relevant institutions have carried out a series of fundamental studies and technology research and development demonstrations related to soil desertification process and ecological restoration in Horqin Sandy Land. In the past 3 decades， the desertified land in Horqin area has achieved effective reversal and sustainable recovery under the joint promotion of scientific theories， policies， regulations and major projects. This paper systematically reviews the research progress related to ecological restoration in Horqin Sandy Land in recent years， and makes a preliminary outlook based on the existing research basis and the major needs of national ecological civilization construction， combined with the current situation and trend of regional development， aiming to provide information support for the effective management and high-quality regional development of Horqin Sandy Land.

To investigate the impact of the digital economy on energy utilization efficiency and its underlying mechanisms， thereby enhancing energy utilization efficiency in the Yellow River Basin， this study is based on panel data from 78 cities during the period from 2014 to 2023. The non-desired output super-efficiency SBM model and entropy-weighted TOPSIS method are utilized to measure energy utilization efficiency and the digital economy development index， respectively. Furthermore， a bidirectional fixed effects model， mediating effect model， and moderating effect model are employed to analyze the relationship between the digital economy and energy utilization efficiency. The findings indicate that： （1）The energy utilization efficiency in the Yellow River Basin has been continuously improving over the study period； however， and the overall level remains low， with significant spatial disparities characterized by a distribution pattern of "higher in the east and lower in the west". （2） The digital economy exerts a significant positive impact on energy utilization efficiency， particularly pronounced in the downstream regions of the Yellow River. （3） The digital economy enhances energy utilization efficiency by improving industrial structure and technological innovation levels. Additionally， the degree of government intervention significantly moderates the positive relationship between the advancement of industrial structure， technological innovation levels， and energy utilization efficiency.

In arid and semi-arid terrestrial ecosystems， the dynamics of key plant populations constitute a central driver of vegetation structural reorganization， and serve as the ecological foundation for vegetation responses to precipitation changes. This study focuses on the Horqin Sandy Grassland vegetation of northern China's semi-arid area. Through controlled experiments manipulating precipitation regimes， we investigated the response pathways of diverse key populations to precipitation changes and their characteristics of ecological functional differentiation， thereby identifying the population-level configuration patterns of vegetation structure. Results demonstrated that： precipitation reduction drove the replacement of perennial dominant species （e.g.， Cleistogenes squarrosa， with its importance value and ecological niche breadth declining from 0.21 and 5.06 to near zero， respectively） by annual plants， while precipitation increase only moderately adjusted the dominance hierarchy among species. Indicator species exhibited distinct functional differentiation under precipitation changes： perennials （e.g.， Cleistogenes squarrosa with an indicator value of 0.25） dominated under increased precipitation， semi-shrubs （e.g.， Lespedeza davurica with an indicator value of 0.23） prevailed under decreased precipitation， and annuals （e.g.， Salsola collina with an indicator value of 0.39） proliferated under seasonal droughts. Generalist species showed heightened sensitivity to seasonal droughts， whereas specialists responded markedly to extreme precipitation fluctuations. Niche contraction in both groups triggered an species percentage increase in neutral taxa to fill ecological vacancies. Key populations characterized by high-importance values， strong indicator properties， broad ecological niches， or specialized niches can significantly contributed to inter-treatment differences. Notably， these key populations showed higher sensitivity to extreme precipitation changes， negative precipitation anomalies， and spring-season precipitation changes. This work underscores the feasibility of optimizing vegetation configurations by integrating precipitation regimes with their corresponding buffering species， providing theoretical foundations for adaptive management of sandy grassland ecosystems in semi-arid regions.

To explore the effect of fertilization on high and stable yields in sandy corn farmland in semi-arid areas and optimize the fertilization regime， six treatments， namely no fertilization （CK）， straw returning to the field （ST）， chemical fertilizer （CH）， farmyard manure （FA）， decrease 50% of chemical fertilizer and farmyard manure （CF_2）， and decrease 50% of chemical fertilizer （CH_2）， were positioned and set up in the sandy farmland ecosystem. The results showed that： （1） Chemical fertilizer， farmyard manure and combination of chemical fertilizer and farmyard manure increased the plant height， stem diameter， ear height， ear length， ear diameter， row number of grains and 100 grains weight of corn. The combination of chemical fertilizer and farmyard manure had a stronger promoting effect on plant height and ear height， while the single application of chemical fertilizer had a more obvious promoting effect on ear length and 100 grains weight. （2） Chemical fertilizer， farmyard manure and their combination increased the aboveground biomass and total biomass by 68.2%-196.3% and 54.9%-163.0%， respectively， compared with CK and ST. Chemical fertilizer， farmyard manure and their combination increased the root biomass by 108.0%-126.9% compared with CK. The chemical fertilizer only and the combination of chemical fertilizer and farmyard manure increased the grain yield by 29.9%-292.6% compared with CK， ST and FA. Fertilization has a significant impact on the temporal stability of aboveground biomass and total biomass. （3） Plant traits， ear characteristics have a strong positive correlation with biomass/grain yield and their stability. Comprehensive analysis suggests that halving the application of chemical fertilizer and farmyard manure can significantly enhance the productivity of corn in sandy farmland.

As one of the regions in China most severely impacted by land desertification， the habitat quality of the Horqin Sandy Land is closely tied to the regional ecological environment and ecological security. This study used the Integrated Valuation of Ecosystem Services and Tradeoffs （InVEST） model to assess habitat quality in the Horqin Sandy Land from 1990 to 2022. Methods such as the dynamic degree model， Theil-Sen median trend analysis， Mann-Kendall test， Hurst index， and geographic detector were employed to analyze the spatiotemporal changes in habitat quality and its influencing factors. Additionally， the study coupled the Grey Multi-Objective Programming （GMOP） model with the Patch-generating Land Use Simulation （PLUS） model to forecast habitat quality under four scenarios： ecological， natural， economic， and comprehensive development. The results show a general improvement in habitat quality from 1990 to 2022， with sustainable characteristics. Spatially， the habitat quality follows a west-high， east-low distribution pattern， with 14.73% of the area showing significant improvements. The geographic detector analysis reveals that vegetation factors are the primary drivers of habitat quality changes， with the interaction of terrain， climate， and human activities providing a strong explanation for spatial heterogeneity. Predictions indicate that by 2035， habitat quality will continue to improve， particularly under the ecological protection scenario， where the greatest enhancement is expected. Areas of low habitat quality will gradually decrease， while medium- and high-quality habitats will expand.

The ecological construction of the Alxa Desert is of significance to the ecological security of China's Three-North Region. The area surrounding the Yabulai Mountains serves as a critical section for controlling the wind-sand convergence where two major deserts meet of Badain Jaran Desert and Tengger Desert. The establishment of windbreak and sand-fixation forest and grass belts， as well as the stable maintenance of their ecological functions， are vital for ensuring the smooth operation of regional transportation arteries and the safety of human settlements within oasis environments. Based on an assessment of current sand hazards and sand control systems in the region， this paper classifies the area into three types： engineering-biological sand control zones in strong wind-sand corridors， near-natural restoration zones along the desert edges on both sides of the Yabulai Mountains， and engineering-biological sand control zones at the edges of industrial-mining towns and oases. It also proposes corresponding windbreak and sand-fixation forest-grass belt construction technologies and comprehensive management plans for each zone， aiming to provide decision-making support for regional ecological construction.

Artificial sand-fixing vegetation serves as a critical ecological barrier in desert-oasis ecotone， and its stability is closely linked to the effectiveness of regional ecological protection.As a representative type of sand-fixing vegetation， Haloxylon ammodendron plantations undergo distinct developmental phases over time， which markedly influence the soil environment and related ecological functions. To evaluate these effects， Haloxylon ammodendron plantations aged 5， 10， 20， and 30 years at the northern edge of the Zhangye Oasis were selected as study sites， with mobile and fixed sand dunes serving as controls. This study systematically investigated the physicochemical properties， nutrient contents， and ecological stoichiometry of topsoil， assessed the long-term impacts of plantation age on the carbon， nitrogen， and phosphorus stoichiometry and their stocks， and further examined the coupled interactions between biotic and abiotic factors， along with the feedback mechanisms that drive the restoration dynamics of artificial sand-fixing ecosystems. The study found that surface soil C∶N ratios were significantly higher in fixed duns than in mobile dunes， while the N∶P ratios exhibited the opposite trend. The establishment of H. ammodendron plantation gradually decreased surface soil C∶N ratios and increased N∶P ratios， with a distinct pattern observed in the 30-year-old H. ammodendron plantation， where C∶N ratios increased and N∶P ratios decreased. H. ammodendron plantations significantly increased topsoil organic carbon and inorganic nitrogen stocks 10 years after establishment. Meanwhile， total nitrogen and total phosphorus stocks increased with planting age， with the highest total nitrogen stock observed in the 20-year-old H. ammodendron plantation. Shrub cover， herbaceous cover， macro-arthropods， and soil silt and clay content explained 67.89% of the variation in surface soil carbon， nitrogen， and phosphorus stoichiometry. Shrub cover， herbaceous cover， macro-arthropods， soil silt and clay content， soil pH， and soil salt content explained 70.70% of the variation in surface soil carbon， nitrogen， and phosphorus stock. In summary， the establishment of H. ammodendron plantations led to a continuous decline in herbaceous cover and soil pH over time， while shrub cover， soil silt and clay， the macro-arthropods activity density， and soil salt content increased primarily during the pre- and mid-establishment stages. Together， these changes played a key role in driving variations in surface soil carbon， nitrogen， and phosphorus stoichiometry and stock.

Desert steppe degradation is one of the most concerning ecological issues. Therefore， selecting scientifically restoration measure is key to achieving ecological restoration and sustainable development of degraded desert steppe. Due to the limited effectiveness of single measure， the integration of multiple approaches has become an important strategy for restoring degraded desert steppe. We conducted a 5-year study in a typical degraded desert steppe of northern China. We set four treatments （control， sand-fixing barrier， sand-fixing barrier + litter addition， and sand-fixing barrier + litter addition + organic fertilizer） to quantify and compare the specific effects of different measures on desert steppe restoration by monitoring vegetation coverage， soil environmental factors， and soil nutrients. The results showed that： （1） sand-fixing barriers significantly enhanced vegetation coverage but did not substantially alter soil nutrient content or microbial abundance； （2） sand-fixing barrier + litter addition improved soil physicochemical properties through organic matter input， and demonstrated greater enhancement in vegetation coverage compared to control and using sand-fixing barrier alone；（3） sand-fixing barrier + litter addition + organic fertilizer had the most pronounced improvements in vegetation and soil characteristics at the beginning of the experiment. However， the effects of fertilizer lasted shortly， and with no difference from the sand-fixing barrier + litter addition over time （except for soil microbial abundance）. Considering restoration effectiveness， economical cost and practicality， sand-fixing barrier + litter addition represents the optimal restoration measure for degraded desert steppe ecosystems.

Ecological sensitivity is a critical indicator for evaluating the response and self-regulation capacity of ecosystems under external disturbances. It plays an essential role in ecological redline delineation， spatial planning， and the construction of regional ecological security patterns. This study takes Qingyang City， a typical gully region on the Loess Plateau， as the research area. Based on multi-period remote sensing and land use data from 2000 to 2020， four key ecological indicators—elevation， aspect， NDVI， and land use type—were selected to build an ecological sensitivity evaluation system. The Analytic Hierarchy Process （AHP） was employed to determine index weights， and GIS-based overlay analysis was used to map spatial distribution patterns of ecological sensitivity and explore their coupling mechanisms with land use and vegetation cover changes. The results show that： （1） Land use in Qingyang has significantly improved over the past two decades， with continuous expansion of forest and grassland and a notable reduction in unused land.（2） NDVI exhibited a trend of “low values increasing and high values remaining stable，” indicating significant vegetation restoration driven by ecological projects.（3） Ecological sensitivity displayed clear spatial differentiation， with lower sensitivity in the northwest and central areas and higher sensitivity in the southeast. Medium and high sensitivity zones dominated the region， while highly sensitive zones were mainly distributed in key ecological barrier areas such as the Ziwuling forest and the headwaters of the Jing River. This study provides a practical and replicable approach for ecological sensitivity evaluation in loess hill and gully regions， offering scientific support for ecological zoning， land management， and environmental policy development.

Rainfall variation and nitrogen addition significantly influenced the structure and function of grassland ecosystems in semi-arid regions. To elucidate their effects on vegetation community characteristics， soil physicochemical properties， and the regulatory mechanisms underlying biomass formation， a field-controlled experiment was conducted in the sandy grassland of the Horqin Sandy Land during 2021 and 2022. Four rainfall treatments were applied during the growing season （May to September）： a 60% reduction （-60%） and a 60% increase （+60%） in precipitation. To further assess the effects of early-season extreme drought， two additional treatments were established： a 100% reduction for 60 days （-60d） and a 100% increase for 60 days （+60d） from May to June. A nitrogen addition treatment （20 g·m^-2 per year） was also included. The results revealed that changes in precipitation and nitrogen addition had significant but temporally inconsistent impacts on community structure， biodiversity indices， and soil physicochemical attributes. Rainfall reduction notably decreased vegetation cover and increased species density. Among the drought treatments， early-season extreme drought （-60d） imposed a stronger suppressive effect on aboveground biomass than whole-season rainfall reduction （-60%）. Nitrogen addition significantly enhanced vegetation cover and both above- and belowground biomass. However， it also reduced species richness， intensified interspecific competition， and facilitated the dominance of competitive species， resulting in decreased community diversity， lower evenness， and increased dominance. With respect to soil responses， nitrogen addition induced soil acidification， leading to a reduction in clay particle content. Under drought conditions， species with drought-tolerant or drought-avoiding traits and larger individuals became dominant， thereby enhancing community biomass. Nitrogen addition further promoted biomass accumulation by increasing vegetation cover and plant height. Overall， rainfall variability and nitrogen enrichment jointly reshaped vegetation structure， altered resource competition dynamics， and modified soil physicochemical processes， thereby exerting profound effects on the biomass formation mechanisms in semi-arid sandy grasslands.

In arid desert areas， some natural vegetation mainly depends on groundwater for survival， which is known as groundwater-dependent vegetation. Protecting groundwater-dependent vegetation is an important task in ecological construction in arid areas， and using remote sensing products to rapidly identify groundwater-dependent vegetation has important practical significance for ecological protection in arid areas. We selected six sample areas dependent on different sources of moisture in the Hexi Corridor， analysed the correlation between vegetation NDVI changes and precipitation from 2001 to 2020 in each sample area， and explored the feasibility of applying NDVI products to identify groundwater-dependent vegetation. The result shows that the average NDVI value of the six sample areas from 2001 to 2020 was between 0.11-0.29， and the coefficient of variation was between 0.07-0.59； the maximum value was between 0.20-0.32， and the minimum value was between 0.07-0.26. Pearson's correlation results showed that the correlation coefficients between the average NDVI and growing season precipitation in the six sampling areas ranged from 0.16 to 0.55， the correlation coefficients between the maximum NDVI and growing season precipitation ranged from 0.24 to 0.65， and the correlation coefficients between the minimum NDVI and growing season precipitation ranged from 0.10 to 0.30； the correlation coefficients between the variability of NDVI and the growing season precipitation ranged from 0.21 to 0.70. The correlation coefficients between NDVI variability and growing season precipitation ranged from 0.21 to 0.70. In general， the correlation of desert vegetation NDVI variability with growing season precipitation was greater than that with annual precipitation， and the correlation between groundwater-dependent vegetation NDVI and precipitation was smaller than that of precipitation-dependent vegetation； the correlation of NDVI growing season variability with growing season precipitation was higher than that with the correlation of the mean growing season NDVI with growing season precipitation. Therefore， the growing season NDVI variability can better infer the dependence of vegetation on groundwater through the dependence of vegetation on precipitation.

This article takes the Mu Su Sandy Land as the research object， based on 8 periods of remote sensing data， constructs a landscape ecological risk index， integrates landscape pattern index and geographic detector model， and reveals the spatiotemporal evolution law of desert landscape ecological risk， as well as the impact process of the interaction between natural and human factors on ecological risk. The results showed that from 1990 to 2023， there were significant changes in sandy landscape， with an increase of 5.70×10³ km² in grassland area and a decrease of 8.01×10³ km² in unused land area； With the launch of national ecological projects such as the "Three North" project and the return of farmland to forests and grasslands， low-risk areas of sandy land are concentrated in Shenmu City， Wushen Banner and other places， with an increase of 2.04×10⁴ km² in area. High risk areas are concentrated in Etuoke Banner and Etuoke Front Banner where the sandy land is located， with a decrease of 0.05×10³ km² in area； NDVI （with a contribution rate of over 30%） and annual precipitation dominate the risk evolution in natural factors， while the impact of population density in socio-economic factors continues to increase. The interaction between the two significantly enhances the explanatory power of risk； Ecological projects such as the Three-North Shelterbelt Program have reduced the medium and high ecological risk areas by 57.3%， verified the long-term effectiveness of policy intervention on ecological restoration in vulnerable areas， and provided theoretical and data support for sand control and ecological security barrier construction.

Soil respiration is a crucial component of the terrestrial ecosystem carbon cycle. This study investigated the dynamic changes in soil respiration and environmental factors under extreme drought conditions in the Horqin Sandy Land， aiming to reveal the impacts of precipitation pattern alterations on soil respiration in Caragana microphylla. Based on field control experiments conducted in 2024 in the hinterland of Horqin Sandy Land， five treatments were established： natural precipitation， 50% rainfall reduction， June drought， July drought， and August drought. The results showed that： The soil respiration rate during the growing season initially increased and then decreased； Continuous drought lasting over one month during the growing season significantly reduced soil respiration， while 50% rainfall reduction had non-significant effects； The soil respiration rate exhibited a significant exponential relationship with soil temperature， but showed no significant linear correlation with soil moisture content； Soil hydrothermal factors， plant characteristics， and enzyme activities collectively explained 48% of the variation in soil respiration rates， with soil hydrothermal factors demonstrating the highest independent explanatory power （37%）. This study provides important scientific references for accurately estimating carbon emissions in Horqin Sandy Land under future precipitation change scenarios.

The construction of a nature reserve system with national parks as its core is a major breakthrough in the institutional system of ecological civilization， and a key area for promoting the construction of a beautiful China and realizing the modernization of harmonious coexistence between human beings and nature. Qilian Mountain National Park is in the early stage of development， and it is necessary to refer to the international experience and combine with the construction practice， to further inspire the working idea and strengthen the management policy and legal system construction， and constantly improve the construction and development path. Through comparative research， literature checking， policy and law analysis and other methods and means， the research is carried out from the aspects of practice and research progress of national parks， management system and law， existing problems. The suggestions are put forward， such as optimizing the management mode， perfecting the coordinating mechanism， improving the law and regulation system， and strengthening the scientific and technological support and safeguard measures.

The relative height of dunes serves as a pivotal parameter in understanding the formation and evolutionary dynamics of aeolian landforms. Accurate determination of the base point for dune height measurement is crucial for this parameter's quantification. Traditional manual measurement techniques are not feasible for extensive studies due to their limitations in scalability and subjectivity involved in selecting base points. Furthermore， existing digital terrain analysis algorithms have not adequately addressed the criteria for base point selection. This study introduces the concept of contribution efficiency to quantify the significance of local terrain minima in contributing to the relative height of dunes. Utilizing this concept， the most appropriate base point is identified from among numerous local minima adjacent to the dune crest. An analysis comparing two deserts with three distinct types of terrain data demonstrates that： （1） The proposed method for base point selection outperforms previous techniques in terms of both spatial distribution and height value accuracy； （2） The error associated with horizontal data resolution exceeds that of elevation accuracy， with dunes less than 50 meters in height being particularly susceptible to such errors； （3） The maximum dune height as determined by this method aligns closely with field measurements. This research facilitates large-scale， objective， and fully automated dune height measurement， which holds potential for global application. It represents an innovative approach to the morphometric analysis of dunes and offers a valuable reference for base point selection in field surveys.