Soil carbon and nitrogen storage are of great significance to carbon and nitrogen cycles and global change researches. We use correlation analysis， random forest and SHAP interpretation methods to elucidate the distribution and variation patterns of soil surface carbon and nitrogen storages and determine the key influencing factors in the Urat National Nature Reserve of Haloxylon ammodendron. In this study， 61 plots were set up in the protection zone using the grid layout method， and the surface soil （0-20 cm） was collected to determine the soil carbon and nitrogen storage and analyze their main influencing factors. The carbon storage in the core area （1 429.91 g·m^-2） was significantly higher than those in the buffer area （1 194.09 g·m^-2） and the experimental area （986.36 g·m^-2）. The soil nitrogen storage in different areas did not differ significantly （P>0.05）， with 76.79 g·m^-2， 62.39 g·m^-2 and 51.28 g·m^-2 in the core， buffer and experimental area， respectively. Soil pH， electrical conductivity， the height of H. ammodendron， species richness， vegetation cover and herbaceous biomass differed significantly （P<0.05） among the three areas based on ANOVA. The key factors affecting soil carbon storage were soil carbon content， soil nitrogen content， soil water content， electrical conductivity， soil bulk density， the height of H. ammodendron， plant density and pH. SHAP analysis showed that soil bulk density and pH were negatively correlated with soil carbon storage， while the other significant factors were positively correlated with soil carbon storage. The key factors affecting soil nitrogen storage were soil nitrogen content， soil carbon content， electrical conductivity， soil bulk density， soil water content， the height of H. ammodendron， vegetation cover， C/N and plant density， and SHAP analysis showed that soil bulk density and C/N were negatively correlated with soil nitrogen storage， while the other significant factors were positively correlated with soil nitrogen storage. It was also found that the contribution to soil carbon and nitrogen storage was significantly increased for the average plant height of H. ammodendron higher than 2 m. Therefore， the sustainable management of H. ammodendron is beneficial on soil quality improvement in the Urat National Nature Reserve of H. ammodendron forest.

The oasis desert transition zone at the northern foot of Tianshan Mountain has a fragile habitat. By revealing the ecological characteristics of vegetation in this area， we can then speculate on its succession trends， hoping to provide a theoretical basis or reference suggestions for ecological protection. Based on the investigation of 39 typical sites in research area， the dominant plant niche and interspecies connection are analyzed by important values， niche width， niche overlap， χ² test， Pearson correlation test and Spearman rank correlation test. The results show that：（1） There are 28 dominant species in the study area， and the niche breadth was significantly different. There was no significant correlation between the niche breadth measurement results and the change trend of important values. The ecological width index of Alhagi camelorum， Ceratocarpus arenarius，Haloxylon ammodendron is large. The B_L and B_S of Alhagi camelorum are 12.11 and 2.77， are the largest. （2） The niche overlap index of dominant plants in the study area is generally small， the demand for environmental resources is not similar， and the interspecific competition is weak. Competitive relationshipbetween Cerastium fontanum and Trifolium repens， Poa annua and Cerastium fontanum is obvious， and it is weak between Ceratocarpus arenarius and Poa annua， Poa annua and Alhagi camelorum. （3） The plant communities in the study area show no significant positive association. The three tests show that most species pairs had no significant relationship， and the species show an independent distribution pattern. The stability is relatively poor， and the correlation is relatively weak. It is in the early stage of succession， and the structure and function are not perfect. （4） The Pearson correlation coefficient and Spearman rank correlation coefficient between species are significantly positively correlated with the degree of niche overlap， which show that the stronger the positive （negative） association between species， the greater （ smaller ） the degree of niche overlap.

The sandy region to the east of the Yellow River in Ningxia is a transitional region in the agro-pastoral ecumenical zone in northern China. Understanding the law of the development of desertification in this region is helpful to coordinate the local man-land relationship and guide the implementation of ecological construction project. The Landsat data were used to extract the information of desertification land for five periods of 2000， 2005， 2010， 2015 and 2020 in the sandy region to the east of the Yellow River in Ningxia， then the temporal and spatial characteristics of desertification land were analyzed by combining the barycenter transfer model， and the effects of climate change and human activities on regional desertification evolution were stripped and recombined by multiple regression residual analysis method. The results show that the overall area of desertification land in the sandy region to the east of the Yellow River in Ningxia decreased， the degree of desertification was reduced， and the desertification was reversed from 2000 to 2020. The degree of desertification in the northern part of the region was more serious than that in the southern part. The barycenter of all kinds of desertification land moved northward， and the degree of desertification reversal was more significant in the south than in the north. Regional desertification reversal is mainly influenced by climate change and human activities.

The soil erosion in China was characterized by various types and complicated processes. It is of great significance to accurately quantify the temporal variation and spatial patterns of soil wind erosion and water erosion intensity in watersheds， to identify regional dominant erosion types for reasonable arrangement of soil and water conservation measures. This study quantified the temporal and spatial patterns and evolution of soil wind erosion and water erosion intensity in the Yellow River Basin from 2000 to 2020 combined remote sensing monitoring， field survey， and model simulation， revealed soil erosion type area， and its significance to zoning control of soil erosion. The results showed that： （1） The intensity of soil wind erosion and water erosion in the region showed a downward trend as a whole， while the wind erosion and water erosion showed a fluctuation and continuous decrease， respectively. In the past 20 years， the modulus of soil wind erosion and soil water erosion have respectively decreased at a rate of 18.88 t·km^-2·a^-1 and 34.98 t·km^-2·a^-1. （2） The type zones dominated by soil wind erosion and soil water erosion accounted for 16.35% and 83.65% of the total land area of the region， respectively， and the overall performance of soil erosion type zoning from north to south was the transition from soil wind erosion to water erosion. The areas dominated by soil wind erosion were distributed in the upper reaches of the main stream of the Yellow River and the Ordos inland flow area， accounting for 41.53% and 28.57% of the area of soil wind erosion area， respectively. Moderate erosion intensity of soil wind erosion accounted for the largest proportion， 24.72%. The areas dominated by soil water erosion were distributed in the middle reaches of the Yellow River （25.04%）， the Wei River-Yiluo River system （22.06%）， the source water system of the Yellow River （18.60%）， the upper reaches of the Yellow River （15.49%）， Huangshui-Taohe River System （13.35%）. Soil water erosion was mainly micro-erosion intensity， accounting for 49.30% of the soil water erosion area， and light （17.28%）， moderate （14.98%） and strong erosion intensity （11.95%） were widely staggered. （3） Desertification control project and soil and water conservation engineering made soil erosion modulus and erosion intensity decrease significantly in areas with strong wind and water erosion. According to the zoning characteristics of soil erosion types， the measures of vegetation restoration and agricultural oases in the soil wind erosion area were discussed. Agricultural cultivation measures， forest and grass measures and engineering measures are used to protect and control soil water erosion areas， in order to provide scientific guidance for the high-quality development of the ecosystem in the Yellow River Basin.

Compared to other terrestrial ecosystems， desert steppe transition zone ecosystems are highly vulnerable and exhibit heightened sensitivity to climate change. Therefore， long-term protection and attention is important. In this study， Hanggin Banner at the edge of Hobq Desert in Inner Mongolia was selected as the research area. Utilizing the Google Earth Engine （GEE） remote sensing cloud computing platform， we analyzed the vegetation change trends in Hanggin Banner by employing the Normalized Difference Vegetation Index （NDVI） from the MOD13Q1 series dataset during 2000-2020. Additionally， we monitored the vegetation evolution pattern using Fraction Vegetation Coverage （FVC） derived from a binary the study period. This analysis was supplemented by spatial transfer matrix and barycentric migration models to elucidate changes in NDVI characteristics within Hanggin Banner. Furthermore， annual precipitation average annual temperature data were utilized to investigate correlations with vegetation normalization index trends in Hanggin Banner. The results indicated the following： （1） Overall， there was a gradual increase in vegetation in the region， with an average annual change rate of 0.0021， demonstrating significant improvement. The vegetation cover was higher in the southeast and lower in the northwest. （2） From 2000 to 2020， Hanggin Banner witnessed considerable enhancement in vegetation coverage， with medium vegetation covering more than 50% of the total area. While low vegetation coverage decreased significantly by 62.35%， there was a slight decrease of 36.39% in high vegetation coverage. However， other grades experienced an increase in their respective coverages， particularly high vegetation which saw a remarkable rise of 150.12%. Moreover， areas with high and medium vegetative coverage tended to expand from north to south while those with medium and low vegetative coverage expanded. （3） There were distinct regional variations observed regarding the partial correlation between NDVI and climate factors. At an inter-annual scale， precipitation had a more pronounced impact on vegetation changes， and the correlation coefficient R reach 0.8 with NDVI， thus indicating that precipitation serves as the primary driving force behind changes in NDVI.

The management of soil salinization along the Yellow River section of Ulan Buh Desert is of great significance to guarantee the ecological security of the Yellow River Basin and realize high-quality development. Based on the traditional and geostatistical analysis methods， this paper analyzed the spatial differentiation characteristics of soil water and salinity， as well as the causes of soil salinization along the Yellow River section of Ulan Buh Desert based on the results of soil water and salinity surveys at 45 sampling sites along the Yellow River section of Ulan Buh Desert. The results showed that the soil water salt content along the Yellow River section of Ulan Buh Desert showed a trend of increasing gradually from west to east and from south to north， with non-saline soils accounting for 41.37% of the total area of the area， lightly， moderately， and severely saline soils accounting for 34.11%， 10.56%， and 8.74% of the total area of the area， respectively. Extremely saline soils appeared near Bayanmuren Sumu， which accounted for 5.22% of the total area of the area. Saline soils were dominated by sulfate saline soils （46.67%） and chloride saline soils （53.33%）. Soil texture had the most significant effects on soil salinity， followed by soil total carbon content and water content. Climatic drought， sparse precipitation， Yellow River diversion for irrigation and groundwater table elevation were the main reasons of soil salinization along the Yellow River section of the Ulaanbuhe Desert.

Quantitative assessment the impacts of climate change and human activities on wind erosion is a prerequisite for scientific prevention and mitigation of wind erosion. By using the National Wind Erosion Survey Model of China （NWESMC）， the controlling variables method and the residual trend analysis method， this paper improved the assessment method for the driving force of wind erosion， and quantitatively evaluated the impact of climate change and human activities on wind erosion in Inner Mongolia Autonomous Region. The results showed that the annual average wind erosion in Inner Mongolia Autonomous Region was 2.59×10¹¹ t， the wind erosion modulus was 2 260.94 t·km^-2·a^-1， mild and light eroded areas accounted for about 78.30% of the total area. The wind erosion modulus showed a significant decreasing trend， and the decreasing rate of wind erosion modulus was 55.95 t·km^-2·a^-2. Climate change is the main driving factor for wind erosion variation， occupy 63.98% of the total area. Human activities is an important factor for wind erosion variation， contributing 36.02% to the total area. Further analysis showed that land use type is an important factor for the spatial distribution of wind erosion. Wind speed and vegetation coverage are the main factor for the temporal variation of wind erosion. The variation of vegetation coverage affects by climate change and human activities. Splitting the roles of climate change and human activities in vegetation factor is helpful for accurately assessing the driving forces of wind erosion.

The northern agro-pastoral ecotone is the second largest ecological security barrie， which is a typical ecological fragile zone in northern China. In this study， based on field investigation and indoor analysis， the spatial distribution pattern of soil physicochemical properties in the planted forest in the northern agro-pastoral ecotone was discussed. Combined with climatic factors and tree species identities， the differences of soil physicochemical properties between trees and shrubs and thevariations of soil physicochemical properties in the planted forest with climate gradient were analysed. The results show that： （1） The overall soil of the plantation in the agro-pastoral ecotone was weakly alkaline， the electrical conductivity was 153.55±3.02 μS·cm^-1， the soil bulk density ranged from 0.53 to 2.28 g·cm^-3， the soil water content was 12.54%±0.62%， and the soil total carbon and nitrogen contents were 13.74±0.61 g·kg^-1 and 0.88±0.05 g·kg^-1， respectively. （2） From west to east， soil acidity increased， soil bulk density decreased， soil water content increased， total carbon content decreased， and total nitrogen content increased. （3） On the climate gradient， soil pH， conductivity and bulk density were negatively correlated with precipitation， while soil water content， total carbon and total nitrogen were positively correlated with precipitation. The soil total carbon and total nitrogen contents were negatively correlated with temperature and aridity index. （4） On the regional scale， soil pH of tree soil was significantly lower than that of shrub soil， and soil total carbon and nitrogen contents of shrub soil were higher than those of treesoil.

The Horqin Sandy Land is the largest semi-fixed sandy land in northern China. Tracing its material sources is of great importance to understand the formation and evolution of deserts and reconstruct the migration paths of fragments. Therefore， the composition of fine particles （<63 μm and <11 μm） of eolian sand in the Horqin Sandy Land was analyzed by petrology， elemental geochemistry， Sr-Nd isotope， TIMA automatic mineral identification and U-Pb dating of detrite zircon. The material composition of the Horqin Sandy Land was characterized and its provenance was quantitatively constrained. The geochemical indicators show that the Horqin Sandy land has experienced low chemical weathering and fractional recycling degree. The heavy mineral assemblages are mainly ilmenite， epidote， zircon， garnet， magnetite + hematite limonite， which together with the discriminant diagram of geochemical motherrock indicate that the sediments in the Horqin Sandy Land are mainly derived from medium acid magmatic mother rocks. Further constrained by Sr-Nd isotopes， the main source areas are the southern margin of the Central Asian orogenic belt and the northern margin of the North China Craton， and a small amount of dust originates from the northern border desert of China. The U-Pb ages of detrital zircons in sandy land are mainly from Mesozoic to Late Paleozoic （200-600 Ma） and Paleoproterozoic （1 518-2 000 Ma and 2 200-2 600 Ma）. The comparison with the zircon age spectrum of the potential source area shows that the fine particles in the Horqin Sandy Land contain both near-source material from the Greater Khingan Mountains in the southern margin of the Central Asian orogenic belt by wind and river transport， and ancient bedrock from the Yanshan Mountains in the northern margin of the North China Craton by river transport. Quantitative provenance results of inverse Monte Carlo model show that the Central Asian orogenic belt contributes 53.7% and the North China Craton contributes 46.3%. The synergistic effect of wind and river explains the formation of fine particles of wind-sand in the Horqin Sandy Land.

Focused on the variation of particle size characteristics of surface sand before and after sandstorms in the Taklamakan Desert hinterland， we conducted a systematic particle size analysis of surface sand， including parameter calculation， particle size component separation and function fitting. The results show that： （1） The average particle size of the surface sand sample is 143 μm， dominated by fine and very fine sand， which together accounted for 87.02%； after the sandstorm， dominated by very fine sand and fine sand， which together accounted for 79.44%. （2） The average particle size of the sandstorm sample is 82 μm， dominated by powdery sand and very fine sand， which together accounted for 80.89%. （3） After the sandstorm， the average particle size of the surface sand decreased by 46 μm， and the content of clay， powder and very fine sand increased， indicating that the large amount of fine-grained material carried by the dust storm had an important influence on the particle size characteristics of the surface sand. （4） The variation of sand particle size with height is mainly controlled by wind speed， with wind speed thresholds ranging from 7.7 m·s^-1 to 8.4 m·s^-1. In three-dimensional space， the second-order polynomial surface model can well fit the function relationship between the average sand particle size and the average wind speed.

Aeolian sand activities threaten highway safety operation in Wuhai-Maqen Highway （G1816） in Tengger Desert. The characteristics of wind conditions， grain size and near-surface（0-2 m）horizontal dust flux in typical section of protection system were investigated. The results show that the average annual wind speed is 3.13 m·s^-1， the average annual sand driving wind speed is 7.66 m·s^-1， the frequency of sand driving wind is 17.6%， and the direction of sand driving wind is mainly W-NNW， E and S. The annual sand drift potential is 187.57 VU， the resultant sand drift potential is 78.6 VU， the direction of resultant sand drift potential is 135°， and the RDP/DP is 0.419， which belongs to the low wind energy environment and blunt bimodal wind condition with moderate wind direction variability. The spatial difference of horizontal sand and dust flux in the protection system is significant， and the horizontal sand and dust flux decreased by 99% from moving dune observation point to straw checkerboard barriers observation point near the road upwind， and it also decreased by 93.6% from moving dune observation point to checkerboard barriers observation point near road downwind. The surface sediment in the protection system is mainly consist of medium sand and fine sand， and the particle size of sand and dust at different heights gradually becomes finer from the outside to the inside of the protection system.

The operational agricultural drought monitoring system is a powerful tool for monitoring and predicting agricultural drought， as well as agricultural risk assessment and prevention. In order to better promote the development of the operationalization of agricultural drought monitoring， we systematically reviewed four types of commonly used drought indices based on meteorological variables， soil moisture， vegetation status and multivariate， and analyzed the characteristics of operational agricultural drought monitoring systems in the United States， China， Europe and the United Nations Food and Agriculture Organization， etc. in detail， and discussed the problems existing in operational agricultural drought monitoring systems. For example， the quality and fusion of data are unstable， the construction of the comprehensive drought index is uncertain， the temporal resolution of monitoring needs to be improved， and the hydrological conditions and the growth process of crops are not considered. Looking forward to the future， the operational agricultural drought monitoring system should develop further from using multi-source data to monitor drought， considering regional spatial and temporal differences and the accumulation and lag between different indicators when constructing comprehensive indicators， strengthening the role of machine and deep learning in the construction of comprehensive indices， developing daily time-scale monitoring of drought to deal with the occurrence of flash drought events， strengthening the role of crop growth process models and advanced technical means in drought monitoring.

Grassland is a crucial part of terrestrial ecosystem and plays an important role in maintaining regional ecological security. Soil multifunctionality （SMF） is a comprehensive index to measure the provided soil multiple functions， which has imperative significance for assessing grassland ecosystem function and regional sustainable development. However， the current SMF studies are still in the initial stage， and the objects in studies are mostly farmland ecosystems， while there are relatively few studies on grassland and other natural ecosystems. In addition， there is few ecolgoists to elucidate the relationship among SMF of grassland ecosystems， plant and soil microorganisms， as well as the effect of global change on SMF in grassland ecosystems. Therefore， this paper discusses the study progress of SMF from five aspects： the concept of SMF， quantitative indicators and methods， the relationship among plants and soil microorganisms and SMF， the impact of global changes on SMF and the spatial variability of SMF， and reviews the change and mechanisms of SMF in grassland ecosystems. Based on the existing problems in the existing studies， the following topics should be focused on： （1） Unified SMF quantitative methods； （2） The transformation mechanism of SMF at different spatial scales； （3） SMF driving mechanism of different grassland ecosystems； （4） Impacts of global changes such as precipitation increase， climate warming and nitrogen deposition， and land use change on SMF； （5） The relationships and interactions between above-ground ecological functions and SMF； （6） Effects of root functional traits on SMF and contributions of plants to SMF at different scale levels； （7） The contribution of rare species of microorganisms and plant-soil animal-soil microbial multitrophic linkage on SMF.

In recent years， various counties in the Zoige Basin have taken measures such as setting checkerboard sand barriers and planting shrubs to control desertification， and many wandering dunes have been fixed. To explore the changes of grain size characteristics of sand dune surface sediments under the influence of sand-fixing vegetation， surface samples were collected before and after sand dune control on the left bank of the Yellow River in Maqu County， Zoige Basin， and the relevant data were compared and analyzed. The results show： （1） After vegetation fixation， the proportion of silt and clay components increased from 1.3% to 9.9%， and the mean particle size decreased from 181.9 μm to 162.0 μm. The grain size components of surface sediments became finer， the sorting of dunes became worse， the skewness changed from near symmetry to very positive skewness， and the kurtosis changed from medium to very narrow. （2） The frequency distribution curve has a secondary peak， and the probability accumulation curve has a sub-component in the suspension section. The overall change from two-stage to three-stage， the particle size of the suspension component becomes finer， and the proportion of the saltation component content decreases from 99% to 87%-88%. （3） Under the combined action of wheat straw grid and sand-fixing vegetation， the effect of desertification control is remarkable， but the local environment of desertification land will also affect the effect of sand control. Therefore， it is necessary to carry out sand control work according to local conditions， pay attention to the dynamic changes of the control area， and timely take measures to adjust.

Clarifying the coupling relationship between urbanization and water ecological environment and its influencing factors has great significance for promoting the ecological protection and high-quality development of the Yellow River Basin. Based on the analysis of the coupling mechanism between new urbanization and water ecological environment， this paper analyses the spatial and temporal pattern of the coupling between the two systems and its driving factors by using the coupling coordination degree and spatial econometric model. The main conclusions are as follows： （1） From 2006 to 2021， the coupling coordination degree between new urbanization and water ecological environment in the Yellow River Basin had improved steadily but were overall low， which had risen from the stage of near imbalance to the stage of primary coordinated in general. Meanwhile， the coupling coordination degree of the downstream is greater than that of the middle reaches and upstream. （2） The coupling coordination degree has a significant spatial spillover effect， and the influence strength of the spatial spillover effect from high to low is the lower， middle and upper reaches of the Yellow River respectively. （3） Local government capacity has a positive promotion on the local coupling coordination but a negative spillover effect on that of neighboring cities； Local population agglomeration and environmental regulation negatively affect its own coupling coordination； Capital accumulation positively influences the coupling coordination of the whole study area through positive spillover effect， while with a negative influence in the downstream； The level of industrialization hinders the coupling coordination development in the whole basin through negative spillover effect； The open and innovative economy has positive impact and spillover effect only on the middle reaches. Differentiated strategies should be adopted to promote the coupling coordination development of new urbanization and water ecological environment across the Yellow River Basin.

The Gurbantunggut Desert is the largest fixed and semi-fixed desert in China which is affected by the westerly circulation most obviously. However， the spatio-temporal characteristics and causes of desert aeolian sand activities since the Holocene are still controversial. Therefore， we selected two sand dunes （sand ridges） profiles at the southern edge of the desert， sampled and measured optically stimulated luminescence （OSL） age and grain size composition of sand samples. Based on the probability density analysis of OSL ages and the end-member analysis of aeolian grain size， the information of aeolian climate changes recorded by OSL ages and grain size parameters was extracted comprehensively. The results show that： （1） The sensitive components extracted from the grain size end-member components of aeolian deposits are important climatic proxies for regional sand activity information. The coarse components transported from near sources reflect the aeolian activities signal at the dune scale， and the fine components transported from far sources reflect the aeolian activities signal at the desert scale. （2） The aeolian sand activity signals at dune scale were mostly recorded by the sand deposition in the upwind edge area with high sand drift potential， while the aeolian sand activity signals at desert scale were mostly recorded by the sand deposition in the downwind area with low sand drift potential. （3） Since the middle and late Holocene， the intensity of aeolian sand activity in the study area can be divided into three stages： 5.0-3.5 ka， 3.5-1.8 ka BP and 1.8 ka BP. The regional and periodic characteristics of aeolian sand activity were the results of the combined effects of westerly circulation changes in the Northern Hemisphere， arid and humid changes of climate， local-scale wind power， sand source， vegetation coverage and other factors.

Dusty weather is an extreme weather phenomenon that occurs frequently in the northern China. It leads to a turbidity of the air and a sharp decline in visibility， causing adverse effects on various aspects of human society. Dust aerosols transported into the atmosphere by strong winds also have a significant impact on weather and climate by modulating atmospheric radiation budget and cloud microphysics. Accurate identification and forecasting of dusty weather are of great significance in ecological protection and climate change mitigation. This paper provides a comprehensive review of recent research on methods for identifying and forecasting dust events. Important methods are described in detail， and their advantages and disadvantages are analyzed and compared. Finally， this paper summarizes the research achievements related to the identification and forecasting of dusty weather and proposes valuable future research directions.

The quantitative effects of vegetation coverage and wind speed on the initiation， transport and sand size distribution of a dust process was studied by WRF-Chem in Inner Mongolia. At the same time， based on the dust data of 119 national stations in Inner Mongolia during 1991-2020 and the global atmospheric reanalysis data of China， the temporal changes and spatial distribution of total dust weather frequency， wind speed and vegetation coverage were counted. It is found that the frequency of total dust weather had decreased， the vegetation coverage had increased， and the zonal （radial） wind had significantly decreased in the areas with high dust rates of Inner Mongolia during 1991-2020. The effect of increasing vegetation cover on dust weather was significantly stronger than that of wind speed： the 5% increase in vegetation cover was comparable to the 30% decrease in wind speed that reduces sand emission. Both vegetation and wind speed have a stronger effect on the reduction of small particle size dust in the dust source. Therefore， desertification control projects such as afforestation should first be carried out in semi-desertification areas with fine particles， and on the basis of protecting native vegetation and rational use of water resources， the final vegetation coverage of afforestation can be increased by 10%-15%.

Aeolian-fluvial interaction is an important geomorphic process in arid and semi-arid areas. The interaction between wind and water power is causal and promoting and has significant spatio-temporal variation characteristics. Under its action， a unique landform landscape， riparian dune， is formed， which is different from the dune landform formed by a single wind accumulation. Taking Wudinghe River Basin in Mu Us Sandy Land as a research area， based on remote sensing image interpretation and other methods， the dynamic geomorphological changes of the interaction between river channels and dunes are studied. The results show that： （1） The vegetation coverage in the Wudinghe River Basin in the Mu Us Sandy Land has recovered well during 1990-2020， and the riparian dunes have gradually solidified， showing the transformation from mobile dunes to semi-fixed dunes and from semi-fixed dunes to fixed dunes. （2） The river channel affects the continuity of the distribution of sand dunes， which makes them fragmented， and also blocks the movement of sand dunes and the transmission of some coarse particle size sand. （3） The geomorphologic pattern of riparian dunes in typical reaches is distributed in a band centered on the river channel， and moving dunes， semi-fixed dunes and fixed dunes are successively distributed along the distance from the river channel. The angle between wind direction and river direction affects the form and distribution of riparian dunes by influencing the mode and intensity of aeolian-fluvial interaction. （4） Riparian dune geomorphic system and river hydrological system maintain a dynamic equilibrium state through the water supply relationship， but excessive human activities may break their thresholds， resulting in increased desertification degree and deterioration of river hydrological conditions.

The Hexi inland river basin is located in arid and semi-arid regions with fragile ecosystems， and there is significant importance in studying the dynamic changes in vegetation cover and its driving factors for understanding the interaction between vegetation and ecosystems. This study uses the mean NDVI during the growing season as the vegetation cover index， employs slope trend analysis and coefficient of variation to analyze the changes in vegetation cover in the Hexi inland river basin from 2000 to 2020， and explores the effects of natural and anthropogenic factors on the spatial differentiation of vegetation using the Geodetector model. The results indicate that： （1） During 2000-2020， the vegetation cover in the Hexi inland river basin exhibited a generally rising trend with fluctuations， having a growth rate of 0.001·a^-1， characterized by a spatial distribution of lower in the northwest and higher in the southeast， decreasing from east to west. （2） Between 2000 and 2020， in most parts of the basin， the vegetation cover remained relatively constant. The areas with increased vegetation cover constituted 35.27% and those with decreased cover constituted 10.91%. （3） The Hexi inland river basin exhibits strong spatiotemporal variability in vegetation cover， with the coefficient of variation ranging from 0.011 to 1.530. The majority of regions demonstrate high stability， with low stability areas primarily focused in the middle and upper reaches of the basin. （4） Natural factors play a leading role， with substantial impacts from evapotranspiration， vegetation types， precipitation， and soil types. Among human factors， land use type emerges as a primary influencer. Revealing the long-term vegetation evolution patterns and characteristics in the Hexi inland river basin offers valuable insights for ecological preservation and soil and water conservation in the region.

Horqin Sandy Land is one of the four sandy lands in China. It is also an important part of the sandstorm source in Beijing-Tianjin-Hebei. The intensification of desertification directly affects the climate environment in Beijing-Tianjin-Hebei. Based on the MEDALUS model， remote sensing and geographic information system technology are used to evaluate the desertification risk of Horqin Sandy Land. The desertification sensitivity index map of Horqin Sandy Land was constructed using soil quality， vegetation quality， climate quality and management quality indices. The results showed that the area with extremely high desertification sensitivity in Horqin Sandy Land was about 2 986.60 km²， accounting for 2.02% of the total area of the study area. The area with high desertification sensitivity was about 6 678.00 km²， accounting for 4.52%； The middle area was about 89 633.18 km²， accounting for 60.71%； The low area was about 48 352.20 km²， accounting for 32.75%. The result showed： （1） MEDALUS model is applicable in the evaluation of desertification sensitivity of Horqin Sandy Land. The assessed areas with extremely high desertification sensitivity index are concentrated in the hinterland of Horqin Sandy Land， both sides of Laoha River， the central and eastern part of Wengniute Banner， northwest of Naiman Banner and the middle part of Kulun Banner. （2） The influence of soil quality index on desertification sensitivity is higher than that of vegetation quality index， climate quality index， and management quality index. Therefore， improving the soil quality is likely to be an effect way to reduce the risk of land desertification in Horqin Sandy Land. （3） With the land use type as the main driving force， the desertification risk has increased in Tongliao City， northwest of Changling County， Horqin Left-wing Middle Banner， Shuangliao city and northern Zhangwu County. In addition， slope has little effect on desertification sensitivity in Horqin Sandy Land.

Sugar transporter （SWEET） plays an important role in plant growth and development and stress response. The purpose of this study is to clone and analyze the expression characteristics of Stipagrosis pennata sugar transporter SpSWEET3 gene， and lay a foundation for further exploring the mechanism and function of its influence on the development of S. pennata root sand trap. The full-length open reading frame sequence of S. pennata SpSWEET3 gene was cloned by molecular cloning technology； The physical and chemical properties of SpSWEET3 gene were analyzed by bioinformatics； The gene expression characteristics were analyzed by qRT-PCR； The subcellular localization was observed and analyzed by laser confocal microscope. SpSWEET3was cloned from the desert plant S. pennata， which includes a 576-bp full-length open reading frame and encodes a basic strongly hydrophobic protein containing 191 amino acids with a relative molecular mass of 21.619 kD. SpSWEET3 belongs to the PQ-loop superfamily and contains the typical MtN3_slv transmembrane domain that catalyzes intracellular sugar efflux. Subcellular localization analysis revealed localization of the gene to the plasma membrane， implying that it may function as a transmembrane protein. qRT-PCR results showed that the SpSWEET3 gene had a higher cumulative expression in S. pennata root tissues， indicating its important role for sand rhizosheath development. Expression of the gene SpSWEET3 was significantly induced by drought stress with PEG， indicating its importance for drought adaptation. Protein interaction analysis showed that SpSWEET3 may transport sugar by interacting with proteins involved in the maintenance of nucleic acid structural stability， transcription factors， and transmembrane transport. The results of this study provide a foundation for in-depth investigation of the functions of SWEET genes and the mechanisms by which they regulate plant tissue development and adaptation to stress.

Microorganisms are an important part of the desert ecosystem and are of great significance to the function and stability of the ecosystem. The current research on desert microorganisms in our country basically covers the main desert areas. This paper summarizes the progress of microbiology research methods， the composition and diversity of desert microbial communities， the distribution characteristics and influencing factors of desert microbial communities， functional diversity of desert microbial communities， and microbial resources based on the existing research results of sandy areas in our country. It is expected to provide an important basis for the development and utilization of microbial resources in sandy areas.

Dust emission in soil wind erosion is one of the core topics in international aeolian research， which develops rapidly in recent years， but the introduction of its research progress is not systematic and comprehensive. This paper combs the research history of dust emission in soil wind erosion at home and abroad， divides the research stages for the first time， refines the main research results of each stage， and introduces some new understandings of the dust emission mechanism. Based on the reclassification of dust emission models， the model establishing process， advantages and disadvantages of various models and their applications in global and regional dust models are introduced. This paper puts forward some hot and difficult issues in the current dust emission research， hoping to provide some reference for relevant scholars to carry out research work in this field.

The grain size composition of dunes is mainly determined by wind regimes， sand sources， and the interaction between dune morphology and airflows. The grain-size composition of sand dunes can reflect the formation process of different types of dunes. Samples were collected from 0-5 cm of the surface layers at the foot of the windward slopes， the dune crests， and the foot of the leeward slopes of 20 barchan or dune chains and 25 parabola dunes in the Mu Us Desert. The grain-size composition of the samples was tested and analyzed to explore their grain size characteristics. The results show that： （1） There are no significant differences in grain-size composition and parameters between barchan dunes and parabola dunes， and the grain -size frequency distribution curves are typical single-peak shapes， but compared with barchan dunes， the parabolic dunes have worse sorting and higher suspended components； The windward slope of parabola dunes has worse sorting and higher coarse sand content than barchan dune. （2） In the statistics of grain-size distribution patterns of sand dunes， the barchan dunes tend to have the finest grain-size on the windward slope， accounting for 65%， whereas the parabolic dunes tend to have the finest grain-size on the leeward slope， accounting for 56%；The grain-size frequency distribution curve also indicated the biased results of the grain-size distribution patterns. （3） Vegetation， the opposite morphology of barchan dunes and parabola dunes and their interaction with airflows are the main factors that cause the differences in grain-size characteristics between the two types of dunes.

The Gobi Desert is a region known for its frequent sandstorms， and is one of the key sources of sandstorms in East Asia. The Tibet Plateau is adjacent to the two major sand source regions of East Asia and South Asia， and is one of the most sensitive regions to climate change in the world. However， the transmission path and mechanism of the Gobi Desert dust to the Tibet Plateau are still unclear. Based on the regional air quality mode WRF-Chem， FNL reanalysis data and the HYSPLIT backward trajectory model， a strong dust event in April of 2020 was used to explore the dust transmission path and transmission mechanism from the Gobi Desert to the Tibet Plateau. The results showed that during this dust event， the east and north slopes of the Tibet Plateau were important channels for dust transmission from the Gobi Desert to the Tibet Plateau. Affected by the circulation situation and the high terrain， the dust transmission efficiency on the north slope of the Tibet Plateau is greater than that on the east slope， while the vertical movement of dust on the east slope is stronger than that on the north slope. The 500 hPa cyclone system east of the Ural Mountains and the Mongolian cyclone jointly control the middle and high latitudes and affect the dust transport process. With the eastward movement of the mid-high latitude cyclone systems， the 500 hPa Xinjiang ridge was destroyed， and the short-wave trough over the Tibet Plateau began to be established. The low layer convergent circulation in front of the short-wave trough is conducive to the maintenance of the 700 hPa closed low pressure， which promotes the northerly wind on the northern slope of the Tibet Plateau， and is conducive to the transport of dust from the northern slope to the plateau. The downward transmission of the 200 hPa upper-level jet stream caused the near-ground easterly wind to prevail in the Hexi Corridor， which was conducive to the transport of the Gobi Desert dust to the plateau. This circulation situation constitutes a favorable wind field for dust transmission from the Gobi Desert from the eastern slope to the Tibet Plateau. The research results further improve the transmission path of the Gobi Desert dust， and provide scientific support for the study of the weather and climate change of the dust influence on the Qinghai-Tibet Plateau and its surrounding areas.

Dryland area is substantial， and the drylands exhibit great sensitivity to global climate change. Nitrogen， which composed of various nitrogen forms， is generally considered the second most limiting resource in desert ecosystems. However， it remains unclear how different levels of aridity affect the spatial distribution of soil nitrogen. Based on data of inorganic nitrogen， organic nitrogen， and total nitrogen from 54 sampling points in the northwest desert region of China， and coupled with climate and environmental data， we explored the spatial variations in nitrogen components under different levels of aridity and the driving factors. Our results indicated a distinct aridity threshold （0.87） for the spatial variations in soil nitrogen along the aridity gradient， meaning an abrupt change in response to aridity. Near the threshold， soil total nitrogen， organic nitrogen content， and the ratio of organic to inorganic nitrogen exhibited rapid increases， while nitrate nitrogen content showed a rapid decrease. Before and after the aridity threshold， both total nitrogen and organic nitrogen content significantly decreased with increasing aridity. In the 0-10 cm soil layer， soil total nitrogen and organic nitrogen content gradually increased with soil depth. The increase in aridity directly or indirectly affected the spatial variation oin nitrogen components through soil water content （SWC）， electrical conductivity （EC）， and pH. The study revealed the impacts of aridity on soil nitrogen balance， which are beneficial for prediction on the response of soil nutrients to environmental changes in drylands， and provide crucial support for making scientifically effective environmental decisions.

To investigate the characteristics and transport rules of cold air in different routes on heavy dust pollution weather in Ningxia， we summarize the circulation characteristics that are easy to cause heavy dust pollution weather in Ningxia on the basis of objective classification of daily ground circulation by using environmental and meteorological data and NCEP reanalysis data. Further， the weather characteristics， pollution sources and contribution rates of heavy dust pollution under the influence of cold air in different routes were analyzed by using the backward trajectory model. The results show that： （1） The cold air routes and circulation pattern that are easy to cause heavy dust pollution weather in the whole region are westward path （A， AN， ANW）， northwest path （AE， ANE， N， NE） and northward path （CE， CSE， E）. （2） Affected by the cold air along the westward route， Zhongwei was the first city to experience heavy dust pollution； Affected by the cold air along the northwest route， Zhongwei and Shizuishan first experienced heavy dust pollution； Affected by the cold air along the northward route， Shizuishan was the first city to experience heavy dust pollution. （3） Under the influence of cold air along the westward route and the northwest route， the transport track of dust in Ningxia was mainly west and northwest， and the dust sources were mainly from the gobi around Ejin Banner， Badain Jaran Desert and Tengger Desert， the contribution of sand source to the PM₁₀ mass concentration was 80-160 μg·m^-3 and above 160 μg·m^-3， respectively； Under the influence of cold air along the northward route， the transport track of dust in Ningxia was mainly northwest and northeast， and the contribution of Tengger Desert， Ulanbh Desert and Mu Us Sandy Land to the PM₁₀ mass concentration was above 140 μg·m^-3， among which， the contribution of the Mu Us Sandy Land in the easterly direction was above 160 μg·m^-3.

Desertification constitutes the primary catalyst for land degradation in the Horqin Sandy Land. Implementing scientifically sound measures to mitigate sand erosion can effectively curb wind-borne sand encroachment， thereby facilitating the restoration and rehabilitation of the vegetation-soil system. This study， focusing on the high and flat mobile dunes in the Horqin Sandy Land， investigates the vegetation community characteristics and soil physical and chemical properties under three sand-fixation measures， namely natural restoration， Artemisia halodendron planting， and grass checkerboard sand barriers. The findings aim to provide scientific guidance for selecting appropriate sand-fixation measures for this specific type of dunes. The results showed that： （1） Under different sand-fixation measures， the plant species richness of flat sand dunes was grass checkerboard （20 species） > planting A. halodendron （18 species） > natural restoration （15 species）； the plant species richness of high mobile dunes was grass checkerboard （14 species） > planting A. halodendron （8 species） > natural restoration （5 species）. （2） There was no significant difference in soil physical and chemical properties between the high and flat moblie dunes. Setting grass checkerboard sand barriers significantly increased soil organic carbon and total nitrogen contents （P <0.05）； with the extension of restoration years， soil nutrient content increased significantly （P <0.05）. （3） There was a significant positive correlation between soil organic carbon and total nitrogen contents and species richness in the high and flat sand dunes （P <0.05）. Establishing straw checkerboard sand barriers could significantly improve the species richness of plant communities and increase soil nutrients to improve soil quality， which was one of the most beneficial measures for the ecological restoration of mobile dunes in the study area. Ecological restoration is a relatively long process. With the extension of sand fixation years， natural restoration， planting A. halodendron and establishing straw checkerboard sand barriers were all beneficial to the ecological restoration of mobile dunes in Horqin Sandy Land.

The arid and semi-arid regions cover more than half of China's land area， which are sensitive to global climate change and human activities with fragile ecological environment. Extreme climate events are frequent and strong in those regions， where the climate anomalies are not only modulated by the internal atmospheric variability， but also affected by the underlying surfaces such as sea surface temperature， sea ice and snow cover. These physical factors play a key role in the climate anomalies in arid and semi-arid regions. This article systematically reviews and sorts out the effects of these physical factors on climate anomalies in arid and semi-arid regions of China. Studies have shown that atmospheric teleconnection is an internal influencing factor of climate anomalies， and the circulation anomalies caused by its phase transition will cause climate anomalies in arid and semi-arid regions by regulating the position of jet stream， planetary wave activity， blocking intensity， and the location of trough-ridge. Sea surface temperature affects the climate anomalies in arid and semi-arid regions by influencing the intensity of monsoon and Walker circulation and the location of western Pacific subtropical high， in the meantime stimulating the response of atmospheric Rossby waves. Moreover， snow cover changes the thermal conditions of the underlying surfaces such as surface radiation and soil temperature and humidity through the albedo effect and hydrological effect， and then has a significant effect on the temperature and precipitation in arid and semi-arid regions by diabatic heating or changing atmospheric baroclinicity. On the basis of summarizing the existing research progresses and achievements， the paper points out that the synergistic mechanism among different factors and the contribution of each factor to the climate anomalies in the arid and semi-arid regions of China still need further research.

The ecological restoration of mine sites is an important measure to promote the harmonious coexistence between humans and nature， and achieve green and low-carbon development. Mining remnants in arid area are characterized by poor site conditions， low vegetation coverage， and strong soil erosion caused by mining activities. The determination of a scientifically rational restoration model is crucial for the success of ecological restoration. In this study， the typical arid limestone mining remnants in Zhongwei City， Ningxia， were selected as the research object. By comparing the soil temperature， humidity， organic matter， plant survival rate， and relative growth rate of new shoots （RGRs） of seven kinds of ecological restoration plants under different soil matrix reconstruction measures， it aims to screen out the optimal mode for ecological restoration of arid limestone mining wastelands and construct an eco-restoration plan combining soil improvement and vegetation reconstruction. The results show that： （1） Soil matrix reconstruction measures are the prerequisite for ecological restoration of limestone mines， which can effectively improve plant colonization environment. The plant survival rates of different soil matrix reconstruction measures are： soil + organic fertilizer > sand + soil + organic fertilizer > sand + soil + compound fertilizer. （2） The range of soil organic matter was 0.56-2.84 g·kg^-1. Plant species and soil matrix and their interaction had a significant effect on soil organic matter content （P<0.001）. （3） The range of RGRs was 1.51-1.87 mm·cm^-1·month^-1， and there were significant differences in RGRs among different plant species. （4） Through Hierarchical clustering analysis， the most suitable ecological restoration mode for the study area was found to be sand + soil + organic fertilizer （with Calligonum mongolicum or Tamarix ramosissima as the selected plants）. This study proposes a joint ecological restoration scheme from the perspective of soil improvement-vegetation reconstruction， which can provide theoretical basis and practical reference for mine ecological restoration in arid areas.

The purpose of this study was to explore the response and age class differences of desert plant of twig and leaf functional traits to drought stress， and to provide theoretical basis for understanding the adaptability of desert plants under extreme drought caused by changes in precipitation patterns and predicting the succession trend of desert plant. In this study， Artemisia ordosica， a typical sand plant in desert areas， was selected as the research object. There were four rainfall gradients， including a control and rainfall reductions of 30%， 50% and 70%， each with three replications. The growth environment of mild， moderate and extreme drought was simulated. On the basis of morphological characteristics， the main twig and leaf functional trait in different age class were studied. Results showed that： （1） A. ordosica could respond to drought stress by increasing leaf thickness， reducing the leaf number， increasing the twig cross-sectional area， reducing the twig length and increasing huber value. （2） Plants of different ages had natural differences in functional traits of twig and leaf. The leaf thickness， total leaf area， leaf number， twig cross-sectional area and twig length were significantly higher in older plants than in younger class. （3） A. ordosica has different responses to precipitation changes in different age class， and low-age A. ordosica mainly regulates specific leaf area， total leaf area， and leafing intensity under adversity. With the increase of age grade， the main regulating functional trait of A. ordosica was the huber value， and the drought resistance of A. ordosica was increased by increasing the potential of water supply from twigs to leaves.

In order to clarify the characteristics and driving factors of oasisization in inland river basin， this paper took the oasis in the Zhangye Basin of Heihe River Basin as the research object， obtained the continuous oasis scale data in the Zhangye Basin from 2000 to 2020 based on land use and NDVI data inversion， and analyzed the law of change of oasis scale and internal structure in the Zhangye Basin. The key factors affecting oasis change were clarified based on the data of economic， cultural and hydrological resources in the basin in the past 20 years. The results show that the oasis scale in the Zhangye Basin has expanded by 485.78 km² in the recent 20 years， showing a trend of the desert to oasis transformation on the whole. In oasis， the proportion of cultivated land and unused land was the largest， and the cultivated land area increased the most in the past 20 years， increasing 19.00% compared with 2000， while the forest land area decreased 25.38% compared with 2000. The changes of oasis scale and internal structure are influenced by natural factors and human activities. Economic development and population play a direct role in oasis scale expansion， and irrigation water consumption plays a decisive role in oasis scale expansion. The results can provide a basis for the rational development of soil and water resources in the inland river basin and the future layout of the oasis structure.

Soil wind erosion is an important threat to the global ecological and environmental security of arid and semi-arid area. Vegetation can effectively reduce the risk of soil wind erosion by reducing wind speed and capturing soil particles. At present， people's understanding of the optimal pattern and coverage of vegetation controlling soil wind erosion still needs to be deepened. With the help of a mobile wind tunnel in the field， this article measured the response of surface sediment transport rate and wind sand flow structure to the coverage of herbaceous plants （Astragalus adsurgens）. The results show that： （1） When the vegetation coverage is small， the distribution curve of wind sand flow structure follows the exponential function distribution law. With the increase of vegetation coverage， the curve shape appears differentiation. （2） Vegetation coverage can effectively reduce the intensity of soil wind erosion and raise the height of sand transport. （3） The surface aerodynamic roughness and vegetation coverage follow a logarithmic function variation law， and their growth rate gradually decreases and eventually approaches zero with the increase of vegetation coverage. There is a threshold phenomenon in the aerodynamic roughness of the underlying surface. （4） The optimal coverage of Astragalus adsurgens for controlling soil wind erosion is about 30%， which can effectively suppress about 90% of wind erosion below a height of 20 cm.

Helan Mountain is the boundary between deserts and desert grasslands in China. Desert grasslands are distributed on the alluvial fan at its eastern foot， playing a positive role in maintaining ecosystem stability. Research is conducted on the spatiotemporal changes in fraction vegetation coverage （FVC）， and the main factors affecting vegetation coverage changes are analyzed. This study utilized Landsat satellite remote sensing data and inverted the vegetation coverage of desert grasslands in the alluvial fan area of the eastern foothills of Helan Mountains from 2001 to 2020 based on a pixel binary model. The spatial pattern and spatiotemporal variation characteristics were analyzed， and the driving factors were analyzed using Sen+Mann Kendall trend analysis， Hurst index， and parameter optimal geographic detector model. The results indicate that： （1） FVC shows a trend of "higher in the northwest and lower in the southeast" in space， mainly characterized by extremely low vegetation coverage and low vegetation coverage. The average annual FVC is 33.38%， and the overall vegetation coverage is at a relatively low level. （2） From 2001 to 2020， FVC showed a significant increase trend （P<0.01）， with an average annual growth rate of 0.25%. Overall， the northwest and southeast showed an improvement trend， with the improved area accounting for 93.24% of the total vegetation coverage area； The average coefficient of variation of vegetation coverage is 0.394， which is relatively stable overall. The eastern and central regions show the most drastic changes in space， with significant spatial differences. （3） The anti sustainability of vegetation coverage in the study area is strong， with an average Hurst index of 0.495， and 44.77% of the areas are greater than 0.5； From a spatial distribution perspective， the Hurst index is higher in the southern and western parts of the study area， indicating a higher sustainability of vegetation change， while the Hurst index is lower in the eastern and northern parts， indicating a lower sustainability of vegetation change. （4） The annual precipitation and land use type are the main factors affecting the spatial distribution of vegetation coverage in desert grasslands in the alluvial fan area of the eastern foothills of Helan Mountain. The interaction detection table shows that the impact of next year's precipitation on vegetation coverage is enhanced after the superposition of other factors， while the impact of topography and slope orientation on vegetation coverage is significantly enhanced； Risk detection indicates that each driving factor has an appropriate range of impacts on vegetation growth in the study area. This study helps to reveal the driving mechanisms of different factors on vegetation changes in desert grasslands in the alluvial fan area of the eastern foothills of Helan Mountains.

The "14th Five-Year Plan" of China proposed to include the Loess Plateau as a key area in the ecological protection and restoration of the Yellow River， implementing integrated watershed management on an appropriate basis. As a typical vulnerable basin in the Loess Plateau， the study of its spatial and temporal changes in habitat quality is of great significance for promoting the improvement of regional ecological environment quality. This study evaluated and predicted the spatiotemporal evolution characteristics of habitat quality in the Wuding River basin at both the whole basin and sub-basin scales， and explored the driving factors of spatial differentiation in habitat quality. The results showed that： （1） During 2000-2020， the proportion of forests and grasslands in the Wuding River basin increased by 11.73%， the area of construction land more than doubled compared to 2000， and the proportion of unused land decreased by 8.46%. During 2020-2050， the land use change situation is expected to remain consistent with the period from 2000 to 2020， but the intensity of change will gradually decrease. （2） During 2000-2020， the habitat quality in the Wuding River basin increased over time， showing a small upward trend overall. During 2020-2050， the growth rate of habitat quality will slow down， and the intensity of change will also weaken， indicating a generally positive development. （3） Land use is the dominant factor driving habitat quality， followed by NDVI and soil type. The study results can provide reference for biodiversity conservation， natural environment protection， and sustainable development in the basin.

To clarify the laws and evolution characteristics of territorial spatial differentiation is the basis and premise for improving governance capacity and building a balanced development pattern of territorial spatial pattern. Based on the theory of production-living-ecological spaces， the land use data from 1995 to 2020 are used to analyze the characteristics of the territorial spatial evolution characteristics of Lanzhou-Xining urban agglomeration by using the methods of land spatial transfer matrix， standard deviation ellipse， nuclear density analysis， comparative advantage index. The results show that： （1） The horizontal regional difference and vertical gradient differentiation of territorial space are obvious in the Lanzhou-Xining urban agglomeration. The ecological space occupied the absolute dominant position， and the production and living spaces are together in the medium altitude of Lanzhou-Xining urban agglomeration； （2） The territorial spatial conversion speed of Lanzhou-Xining urban agglomeration is accelerated， and the largest conversion proportion comes from the production space to living space， which indicates that the interaction between the two types of spaces is obvious. The downtown areas of Lanzhou and Xining， Lanzhou New Area and Linxia city are the conversion hotspot； （3） The production space and living space are distributed from northwest to southeast， and the ecological space is evenly distributed from east to west. The distribution patterns and expansion mode of production-living-ecological spaces are quite different. The shift distance of the gravity center of the living space is the largest， the production space is multi-core diffusion， and the fragmentation trend of the ecological space is enhanced. From the scale of towns， six types of optimal zoning of territorial space are identified， and zoning guidance strategies are proposed to promote the balanced and coordinated development of territorial space in Lanzhou-Xining urban agglomeration.

In this paper， the wind-sand environment wind tunnel simulation was used to measure the sand transport volume， wind-sand flow structure and particle size characteristics of the near-surface wind-sand flow in the gobi under different wind speeds and different gravel coverages. The variation law of gravel coverage on the bed surface under different wind speeds was analyzed to reveal the wind-sand movement on the gobi surface and its influence on the change of gravel coverage on the underlying surface. The results show that： （1） The bed gravel coverage is divided into low and high coverage with 12% as the boundary. Under low gravel coverage and high wind speed （18-24 m·s^-1）， the surface sediment transport volume of gobi changes obviously with wind speed， and the inflection point of sediment transport curve appears as " elephant trunk " effect. With the increase of wind speed， the inflection point moves up， and the smaller the gravel coverage， the greater the curvature of sediment transport profile. Compared with high wind speed， the change of surface sediment transport volume of gobi under low wind speed （6-18 m·s^-1） is not obvious， indicating that the change of sediment transport volume under low gravel coverage is mainly controlled by wind speed， and high gravel coverage has an inhibitory effect on wind sand flow. （2） With the increase of gravel coverage on the bed surface， the frequency distribution curve of sediment transport particle size has a downward trend. The gravel coverage has little effect on the frequency distribution of sediment transport particles， which shows a single peak distribution and only affects the mass percentage of the peak value of the curve. It shows that when the wind speed is constant， the particle size distribution of sediment transport particles in wind-blown sand flow is less affected by gravel coverage. （3） In the process of wind-sand movement， the gravel coverage of gobi bed increases linearly with the increase of wind speed， and there is a strong linear correlation between them. The variation of different coverage under high wind speed is greater than that under low wind speed.

Morphological evolution features can reflect the adaptive strategy of plants to environmental changes. To understand the morphological variations of mosses in adapting to arid sandy area environment， we select three moss species （Bryum argenteum，Didymodon vinealis and Syntrichia caninervis） in the artificial stabilized sand vegetation area on the southestern edge of the Tengger Desert. Using the method of “space replacing time”， we analyzed the morphological and quantitative characteristics of mosses at for levels： leaf， individual， population， and community， in different vegetation age zones （35， 41 and 66 years）. The result revealed certain differences in the morphological traits of the three moss species at the study levels as the vegetation age increased. Specifically， D. vinealis exhibiteda continuous decrease in leaf area， awns， and plant height， while S. caninervis and B. argenteum showed non-continuous variations. The patterns of variation may be to resource competition within and between species. Nevertheless， considering the overall morphological traits， mosses in the artificially stabilized sand vegetation area of the Tengger Desert generally undergo an evolutionary trend from smaller stem-leaf shoots with higher density to larger stem-leaf shoots with low density during the process of ecosystem restoration. This study provides insights into the morphological adaptation strategies of mosses during ecosystem restoration and serves as a scientific basis for species selection of mosses in ecosystem restoration.

The production of oasis thematic data with both oasis uniqueness and structural characteristics is a key basic problem to be solved in oasis research at present. In this paper， a secondary classification system of oasis ecosystem was constructed according to the characteristics of oasis. Then， taking the Hexi inland river basin （HIRB） as the study area， the object-oriented random forest classification and superposition analysis method was used to complete the land structure data mapping of oases in the HIRB from 1975 to 2020 in seven periods， combining with ChinaCover data and Landsat NDVI images. The results show that： （1） the oasis structure data mapping method based on ChinaCover data set can produce oasis thematic data quickly and accurately. （2） the overall accuracy of the primary type of the oasis ecosystem is 96.17%， and the accuracy of the secondary type is 82.64%-92.99%， which is significantly higher than that of the existing land cover products. （3） the proportion of oases in HIRB accounted for 8.97% of the study area in 2020， the primary type was mainly artificial oasis， and the secondary type was mainly cultivated land and grassland. （4） the artificial oasis in the HIRB showed a continuous expansion trend， the desert-oasis ecotone showed a shrinking trend， and the natural oasis shrank at first and then expanded in the past 45 years. The expansion of artificial oasis is mainly due to the increase of cultivated land and construction land， while the shrinkage of ecotone and natural oasis is mainly due to the decrease of grassland. This study can provide a simple and accurate data method for oasis mapping in arid areas.