Particle size characterization and sources of sediments in the Uzhumqin sand dunes

Sediment constitutes the fundamental basis for forming and evolving aeolian geomorphology.The characteristics of sediment particle size offer insights into the development and evolution of sandy terrain,making their study critical to understanding aeolian geomorphology and sand control.In this study,we combined high-density collection of surface sediments in the Uzhumqin sand dunes and GIS spatial analysis to analyze the particle size parameters and changes in the spatial distribution of surface sediments in this region.In addition,we used an end-member analysis to identify the potential sources of the sediments.The results showed that surface sediments in the Uzhumqin sand dunes had distinct spatial distributions.Medium and coarse grain sands dominated the sediments in the dunes,and the mean grain size and the sorting coefficient generally increased along the prevailing wind direction,with high values in individual areas related to factors such as material sources and vegetation cover.Skewness was strongly influenced by factors such as landform change and human activity,and spatial variability became more complex.Kurtosis and the soil fractal dimension showed generally decreasing trends along the prevailing wind direction.With dune fixation,the contents of clay and powder particles in the soil increased;the mean particle size,the sorting coefficient,and the fractal dimension of the soil gradually increased,and the skewness and kurtosis gradually decreased.The end-member analysis results indicated the existence of five end-members(EM)in the dune sediments.EM 1 was a mixed component of wind-deposited fine sands and nearby fluvial sediments.EM 2 was the main component of sediments in the study area and was the result of sorting lake sediments by wind action and by the local topography.EM 3 may be a product of river flood deposition.EM 4 and EM 5 had coarser grain sizes.EM 4 was a lake-phase sediment product influenced by topographic and vegetation cover factors,and EM 5 was primarily a river and lake sediment product modified by weathering.The sediment particle size results from the study area indicate that the sediment in the sandy region is generally coarse due to multiple factors,including topography,climate,hydrology,and human activity.Sandy material in the study area originated from nearby,with very little sand being transported from long distances.

Effect of sand-fixing vegetation on the hydrological regulation function of sand dunes and its practical significance

Soil water content is a key controlling factor for vegetation restoration in sand dunes.The deep seepage and lateral migration of water in dunes affect the recharge process of deep soil water and groundwater in sand dune ecosystems.To determine the influence of vegetation on the hydrological regulation function of sand dunes,we examined the deep seepage and lateral migration of dune water with different vegetation coverages during the growing season in the Horqin Sandy Land,China.The results showed that the deep seepage and lateral migration of water decreased with the increase in vegetation coverage on the dunes.The accumulated deep seepage water of mobile dunes(vegetation coverage<5%)and dunes with vegetation coverage of 18.03%,27.12%,and 50.65%accounted for 56.53%,51.82%,18.98%,and 0.26%,respectively,of the rainfall in the same period.The accumulated lateral migration of water in these dunes accounted for 12.39%,6.33%,2.23%,and 7.61%of the rainfall in the same period.The direction and position of the dune slope affected the soil water deep seepage and lateral migration process.The amounts of deep seepage and lateral migration of water on the windward slope were lower than those on the leeward slope.The amounts of deep seepage and lateral migration of water showed a decreasing trend from the bottom to the middle and to the top of the dune slope.According to the above results,during the construction of sand-control projects in sandy regions,we suggest that a certain area of mobile dunes(>13.75%)should be retained as a water resource reservoir to maintain the water balance of artificial fixed dune ecosystems.These findings provide reliable evidence for the accurate assessment of water resources within the sand dune ecosystem and guide the construction of desertification control projects.

Contribution of groundwater to the formation of sand dunes in the Badain Jaran Desert, China

The tallest sand dune worldwide is located in the Badain Jaran Desert(BJD),China,and has been standing for thousands of years.Previous studies have conducted limited physical exploration and excavation on the formation of sand dunes and have proposed three viewpoints,that is,bedrock control,wind dominance,and groundwater maintenance with no unified conclusion.Therefore,this study analyzed the underlying bedding structure of sand dunes in the BJD.Although the bedrock of sand dunes is uplifted and wind controls the shape of dunes,the main cause of dune formation is groundwater that maintains the deposition of calcareous sandstone and accumulation of aeolian sand.According to water transport model and vapor transports in the unsaturated zone of sand dunes,capillary water transport height is limited with film water constituting the main form of water in dunes.Chemical properties and temperature of groundwater showed that aquifers in different basins receive relatively independent recharge from deep sources in the crater.Result of dune formation mechanism is of considerable importance in understanding groundwater circulation and provides a new perspective on water management in arid desert areas.

Characteristics of soil seed banks at different geomorphic positions within the longitudinal sand dunes of the Gurbantunggut Desert, China

Understanding the characteristics of soil seed banks in sand dunes is crucial to stabilize the dune systems and maintain the plant populations in deserts. In this study, we conducted a survey investigation in the field and a seed germination experiment in the laboratory to explore the characteristics of soil seed banks at various geomorphic positions of longitudinal sand dunes in the Gurbantunggut Desert, China. Totally, 17 plant species belonging to 17 genera and 9 families were identified in soil seed banks, and 35 plant species belonging to 34 genera and 17 families were identified in aboveground vegetation. Plant species richness in soil seed banks decreased with increasing soil depth. The highest species richness was presented in the upper slope of the windward slope and the lowest species richness was presented in the base of the windward slope. There was no significant difference in seed density of soil seed banks among the examined seven geomorphic positions. The highest seed density occurred in the lower slope of the leeward slope while the lowest occurred in the crest. Moreover, seed density decreased with increasing soil depth, being the highest in the upper soil layer （0-2 cm）. For both soil seed banks and aboveground vegetation, there was no significant difference in Simpson＇s diversity index among the seven geomorphic positions; however, Shannon-Wiener diversity index and Pielou＇s evenness index showed significant differences among the seven geomorphic positions. Those results showed that although there was no significant difference in seed density of soil seed banks among the seven geomorphic positions, the geomorphic positions significantly affected the species richness, diversity and distribution of soil seed banks. Therefore, understanding the characteristics of soil seed banks at different geomorphic positions of sand dunes is essential to vegetation restoration or reestablishment. Furthermore, the Jaccard＇s similarity coefficients of plant species between soil seed banks and aboveground vegetation at the seven geomorphic positions were low, suggesting that vegetation restoration or reestablishment processes should be promoted through adding seeds to surface layers.

Study of Sand Dunes and Their Effect on Desertification of Cultivated Lands in Shaanxi Province, China Using Remote Sensing Techniques

About half of the arid and semi-arid lands in the world are deserts thatcomprise various types of aeolian sand dunes deposits. In Shaanxi Province, aeolian sand dunes coverconsiderable areas of the Yulin desert and northern Jinbian. Sand dunes are moving in the main winddirection and converting some agricultural area to wasteland. Remote sensing of sand dunes helps inthe understanding of aeolian process and desertification. Remote sensing data combined with fieldstudies are valuable in studying sand dunes, regional aeolian depositional history. In particular,active and inactive sand dunes of the north Shaanxi Province were studied using remote sensing andgeographic information system. In this study, we describe the Landsat thematic mapper (TM) images,covering north Shaanxi Province, which were used to study the distribution, shape, size, trends,density and movement of sand dunes and their effect on desertification of cultivated lands.Estimation was made depending on soil erodibility factor (Ⅰ) and local climatic factor (C) duringthe period (June to September). The result indicates that soil erosion caused sand drift of 8.957 5,7. 03 ton for Yulin and Jinbian, respectively. The mean sand dunes movement rate were 4.37, 3.11 m,whereas, monthly sand dune advance rate were 1. 092 5, 0. 777 5m, for the two locations,respectively. The study reveals that cultivated lands extended obliquely to the direction of sanddune movement are extremely affected, while other segments that extend parallel to the direction ofthe movement are not affected. Accordingly the north Shaanxi Province was divided into areas ofdifferent classes of potential risk. Moreover, blown sands and sand movement from neighboringhighlands also affect the area of western desert.

Endophytic fungi of wild legume Sesbania bispinosa in coastal sand dunes and mangroves of the Southwest coast of India

Evaluation of 450 surface sterilized tissue segments of a seasonal wild legume, Sesbania bispinosa （Jacq.）, of coastal sand dunes and mangroves of southwest India yielded 546 isolates comprising 39 endophytic fungi with six dominant taxa （Aspergillus flavus, Aspergillus niger, Cladosporium tenuissimum, Fusarium moniliforme, Penicillium chrysogenum and morpho sp. 1）. A consortium of saprophytic, pathogenic and toxigenic fungi exists as endophytes in S. bispinosa. Number of segments colonized, number of isolates obtained, species richness and diversity were higher in S. bispinosa in mangroves compared to coastal sand dunes. Seeds yielded more fungal isolates, but species richness and diversity were low. In spite of low fungal colonization in root segments, the diversity was high. Up to 30-40 % endophytic fungi of S. bispinosa differed between coastal sand dunes and mangroves revealing partial host- and habitat-specificity. As S. bispi- nosa is extensively used as green manure and forage in southwest India, further studies especially on the bioactive compounds of its endophytic fungi might broaden its range of uses. In addition to conventional morphologicaltechniques, molecular tools would provide precise insight on the endophytic fungi of coastal sand dunes and mangroves.

Determination of actual evapotranspiration and transpiration in desert sand dunes (Negev Desert) using different approaches

In an arid environment, especially in sandy areas where surface runoff is of no practical importance in the hydrological budget, it is rainfall, dewfall and evapotranspiration that become the most important variables. To assess actual evapotranspiration, several methods （flux-gradient, BREB, eddy correlation） were applied to data from the Nizzana experimental site in the northwestern Negev Desert. Additionally, a model specifically designed for arid environments is introduced in this paper. This zero plane model shows the most reasonable results compared with the other methods, which overestimate evapotranspiration to a large degree. It is shown that plant transpiration is the dominant process in total evapotranspiration while advective processes do not play a major role in the near-ground boundary layer, although the study area is influenced by a sea breeze. Actual transpiration ofArtemisia monosperma was measured in a field experiment to validate the calculated evapotranspiration. The vegetation contributed 41% of the calculated total evapotranspiration in a single month.

Evaluation of Sand Dunes Stabilization Techniques in Baiji District,Iraq

This research was conducted at the sand dunes stabilization research s tation in Baiji district, Iraq. Three techniques for sand dunes stabilization ar e selected: the first method is stabilization by clayey block barriers; the seco nd method is stabilization by dry planting of tamarix (tamarix articulata) cutti ngs and the third is stabilization by using cane branch barriers. Randomized sam ples were taken from the surface and subsurface layers of the stabilized and shi fting sand dunes to evaluate the effect of the three techniques on wind erosion parameters. The results indicate high significant differences between the wind e rosion parameters in the surface and subsurface layers in the stabilized sand du nes, while there are insignificant differences between the subsurface layer of t he stabilized dunes and the surface and subsurface layers in the active sand dun es. The results clarify the fact that there is an increase in the percentage of clay, silt, organic matter, mean weight diameter and the percentage of the dry a ggregates (>0.84 mm). A decrease is found in the rate of disaggregation for the dry aggregates in the samples of the surface layer of stabilized dunes when comp ared with the subsurface layer of stabilized dunes and the surface layer of the shifting sand dunes. There is a positive high significant correlation among the aggregate stability parameters and the percentage of clay and silt, and the cont ent of organic matter in the studied layers.

Sand Dunes Fixation in Baiji District, Iraq

This study was carried out at Sand Dunes Stabilization Researches Station in Baiji district (230 km north of Baghdad, Iraq) to evaluate the effects of local soil conditioners manufactured from oil derivatives and plant residuals on sand dunes fixation as the first step for sand dunes stabilization. The results indicate that the fuel oil has the first place in improving wind erosion parameters in the study area, such as increasing mean weight diameter, dry aggregates percentage, the needed time for complete disaggregation by dry sieving, and decreasing the disaggregation rates. Bitumen emulsion occupies the second place, while the plant residuals occupies the third place and has slight effects on the studied parameters. Effects of conditioners on natural vegetation cover are negative in oil derivatives treatments, while positive in plants residuals treatments.

Morphological Profiles of Sand Dunes from ICESat-2 Geolocated Photons

Aeolian process leads to the transportation and accumulation of sand particles that result in sand dune landforms. The structure and shape of the sand dunes are driven by the parameters of interacting wind force and the material composition of sand within. Cross-section profiles over the sand dunes will essay the geomorphological parameters through which the steady state and rate of sand transport can be computed. National Aeronautics and Space Administration’s novel satellite namely Ice, Cloud and land Elevation Satellite-2 (ICESat-2) hosts a solo sensor namely Advanced Topographic Laser Altimeter System (ATLAS) which is a photon counting instrument that measures the round-trip time of the light pulse being emitted and reflected back from the surface determines the true height of the topographic feature on the Earth. In this article, cross-section profiles generated from the beams of ICESat-2 ground-tracks acquired over sand dunes of the Thar Desert region were analysed for detecting the geomorphological parameters. Observations from the cross-section profiles have resulted in giving unprecedented details about the shapes and morphological settings of various types of sand dunes like barchanoids, parabolic, longitudinal, and transverse dunes. Morphological parameters of sand dunes like the length of the stoss slope, crest height, slip face details, inter-arms spacing, height of the trailing arms, length of the depositional lobes, and sinuosity of the recurring crest lines were retrieved with ease from the Level-2A data product namely ATL03 of ICESat-2/ATLAS.

Cold events of Holocene indicated by primary elements distribution of the high-resolution sand dunes in the Salawusu River Valley

The components of the primary elements in the dune sands for the MGS1 subsection of the Milanggouwan section in the Salawusu River valley, compared with those of modern dune sands, show that they were caused by East Asian winter monsoon in the Mu Us desert during Holocene. The examined ages for the 11 layers of dune sands, based on the average sedimentary rate, are： 0 to 960, 1350-2240, 2470 to 3530, 4000 to 4180, 4290 to 4350, 4380 to 4760, 5040 to 5920, 6570 to 8270, 9020 to 9700, 9880 to 10160 and 10580 to 11080 a BP, respectively. The climatic events indicated by these dune sands are consistent with those records in the Huguangyan volcanic lake, Zoige peat bog, Hulu cave and Dunde ice core, particularly with the climatic fluctuations of the North Atlantic since 11 000 a BP. Among them, patterns from B0 to B8 correspond to the peak values of 0MD, 2D, 4D, 6D＋8D＋10D, 12D, 14D, 16D, 18D and 20D respectively. It might be caused by the North Atlantic ice age induced by the heat circulation, which strengthened the polar high pressure and Siberian-Mongolian high pressure and further led to the dominance of the winter monsoon over China＇s desert area.

The return and loss of litter phosphorus in different types of sand dunes in Horqin Sandy Land,northeastern China

Litter phosphorus （P） return is important to maintain the P cycle and balance in the sandy land of arid areas. In this study, we determined the loss and return of litter P in sand dune areas and elucidated their relation- ship. We investigated litter production and litter P amount, and simulated leaf litter moving dynamics to understand the relationships between the loss of litter P and the total litter P, and between the return of litter P and the total litter P in active （AD）, semi-stabilized （SSD） and stabilized （SD） dunes in Inner Mongolia, northeastern China. The vegetation litter P was 12.6, 94.5, and 201.6 mg P/m2 in AD, SSD, and SD, respectively. A significant movement and loss of leaf litter P with time occurred on the three types of sand dunes. As a result, the loss of P was 7.4, 46.9, and 69.8 mg P/m2 and the return of P was 5.5, 47.6, and 131.8 mg P/m2 in AD, SSD, and SD, respectively. The rela- tionship between both loss and return of P and total litter P in AD, SSD, and SD was revealed by linear regression. The slope of the regression line indicated the rate of loss or return of litter P. From AD to SD, the loss rate showed a declining slope （0.52, 0.32, and 0.17 for AD, SSD, and SD, respectively）, and the return rate showed a rising slope （0.48, 0.67, and 0.83 for AD, SSD, and SD, respectively）. The loss of litter P should be regarded in the local man- agement of vegetation and land in sand dune areas. Improved vegetation restoration measures are necessary to decrease litter P loss to maintain the stability of ecosystems in sand dune areas.

Stabilization of sand dunes with oil residue: Application to civil engineering construction and environmental implications

The present work ascertains the feasibility of oil residue treatment for stabilizing wind-blown sand dunes. Various combinations of natural collapsible saline from the Jandaq desert of Iran and oil residue from distillation towers of Iranian refineries were tested in laboratory experiments. Stabilized sands were evaluated in terms of geotechnical properties, permeability, and oil retention characteristics(i.e. bonding mechanisms, leaching and migrating behaviour of oil residue from the stabilized sands). Since the presence of oil residue in soils can pose an environmental threat, the optimum retention capacity of the stabilized sands is of critical concern. Relative to sand that was not augmented with oil residue, specimens made of 7% oil residues had the highest compressive strength, significantly higher cohesion and load bearing capacity, and considerably lower permeability. The effect of distilled water, saline water and municipal sewage on prepared specimens were also evaluated.

Discussion on wind factor influencing the distribution of biological soil crusts on surface of sand dunes

Biological soil crusts are widely distributed in arid and semi-arid regions, whose formation and development have an important impact on the restoration process of the desert ecosystem. In order to explore the relationship between surface airflow and development characteristics of biological soil crusts, we studied surface airflow pattern and development characteristics of biological soil crusts on the fixed dune profile through field observation. Results indicate that the speed of near-surface airflow is the lowest at the foot of windward slope and the highest at the crest, showing an increasing trend from the foot to the crest. At the leeward side, although near-surface airflow increases slightly at the lower part of the slope after an initial sudden decrease at upper part of the slope, its overall trend decreases from the crest. Wind velocity variation coefficient varied at different heights over each observation site. The thickness, shear strength of biological soil crusts and percentage of fine particles at crusts layer decreased from the slope foot to the upper part, showing that biological soil crusts are less developed in high wind speed areas and well developed in low wind speed areas. It can be seen that there is a close relationship between the distribution of biological soil crusts in different parts of the dunes and changes in airflow due to geomorphologic variation.

TURBULENT FLOWS AROUND SAND DUNES IN ALLUVIAL RIVERS

The sand dunes are typical bed forms of natural alluvial rivers. In this article, a vertical 2-D Reynolds stress model is established for the simulation of turbulent flows around sand dunes, and water-sand boundary conditions are set with particular attention. By numerical simulations, the following conclusions can be drawn. （1） The flow resistance in rivers with sand dunes could be divided into the sand-grain resistance and the sand dune resistance, and the sand-grain resistance coefficient mainly depends on Reynolds number, relative sand grain roughness and sand dune steepness. This coefficient in rivers with sand dunes would be larger than that calculated in a flat riverbed, and the steeper the sand dunes, the larger the sand-grain resistance coefficient. （2） The sand dune resistance coefficient mainly depends on the relative sand dune height and sand dune steepness, the steeper the sand dunes, the larger the sand dune resistance coefficient. （3） For the flat riverbed, the turbulent eddy viscosity coefficient and the sediment diffusion coefficient are approximately identical, but for the sand dune riverbed, in the vertical position, where the sediment diffusion coefficient reaches its maximum, it would be higher than the turbulent eddy viscosity coefficient.

Morphology and formation mechanism of sand shadow dunes on the Qinghai-Tibet Plateau

The formation and development of dunes depend on wind-blown sand movement which is affected by the characteristics of sand material, topography, wind regimes and other factors. In this paper, we investigated two sand shadow dune groups in Shigatse and Za＇gya Zangbo of Tibet and an individual dune in Da Qaidam of Qinghai, and analyzed their topographies and morphologies, and the physical characteristics of the sand, wind regime and sand transport. Formed under harsh conditions behind hills, these mature sand shadow dunes are hundreds of meters long, have significant ridges and crescent dunes downwind, and have a hill pass on one or both sides. Wind tunnel experiments revealed that the hill gap and wind velocity are important factors in the formation of these dunes Sand shadow dunes formed only when the gap spacing is two-thirds of the hill height. When wind velocities are 20 m/s, the sand body is divided into two parts. The hill pass allows the transport of sand by wind, creating a ＂nar- row-pipe effect＂, which causes the transported material to gradually accumulate in the center of the shadow zone. We observed that the following are needed for sand shadow dunes to form： （1） strong winds, sufficient sand, suitable obstacles and a dry climate; （2） one or both sides of the obstacle forming the shadow zone must have a hill pass; and （3） the windward side of the obstacle must have a wide, flat area, providing adequate spacing for wind flow and transport of material and the leeward side must have a sufficiently broad, flat area to allow the release of the transported material. Research results on these newly discovered dunes on the Qinghai-Tibet Plateau could contribute to the understanding of dune geomorphology.

Effects of forest cover types and environmental factors on soil respiration dynamics in a coastal sand dune of subtropical China

Trees on sand dunes are more sensitive to environmental changes because sandy soils have extremely low water holding capacity and nutrient availability. We investigated the dynamics of soil respiration(Rs) for secondary natural Litsea forest and plantations of casuarina,pine, acacia and eucalyptus. Results show that significant diurnal variations of Rsoccurred in autumn for the eucalyptus species and in summer for the pine species, with higher mean soil respiration at night. However, significant seasonal variations of Rswere found in all five forest stands. Rschanged exponentially with soil temperatures at the 10-cm depth; the models explain 43.3–77.0% of Rs variations. Positive relationships between seasonal Rsand soil moisture varied with stands. The correlations were significant only in the secondary forest, and the eucalyptus and pine plantations. The temperature sensitivity parameter(Q10 value) of Rsranged from 1.64 in casuarina plantation to 2.32 the in secondary forest; annual Rswas highest in the secondary forest and lowest in the pine plantation. The results indicate that soil temperatures and moisture are the primary environmental controls of soil respiration and mainly act through a direct influence on roots and microbial activity. Differences in root biomass, quality of litter,and soil properties(pH, total N, available P, and exchangeable Mg) were also significant factors.

Vertical distribution of soil moisture and surface sandy soil wind erosion for different types of sand dune on the southeastern margin of the Mu Us Sandy Land,China

Soil moisture is a critical state affecting a variety of land surface and subsurface processes. We report investigation results of the factors controlling vertical variation of soil moisture and sand transport rate of three types of dunes on the south- eastern margin of the Mu Us Sandy Land. Samples were taken from holes drilled to a depth of 4 m at different topographic sites on the dunes, and were analyzed for soil moisture, grain-size distribution and surface sediment discharge. The results show that： （1） The average soil moisture varies in different types of dunes, with the following sequences ordered from highest to lowest： in the shrubs-covered dunes and the trees-covered dunes the sequence is from inter-dunes lowland to windward slope to leeward slope. The average moisture in the bare-migratory sand dunes is sequenced from inter-dunes lowland to leeward slope to windward slope. （2） Vegetation form and surface coverage affect the range of soil moisture of different types of dunes in the same topographic position. The coefficient of variation of soil moisture for shrubs-covered dunes is higher than that of other types of dune. （3） The effect of shrubs on dune soil moisture is explained in terms of the greater ability of shrubs to trap fine-grained atmospheric dust and hold moisture. （4） The estimated sand transport rates over sand dunes with sparse shrubs are less than those over bare-migratory dunes or sand dunes with sparse trees, indicating that shrubs are more effective in inhibiting wind erosion in the sandy land area.

Limitations on the recruitment of the rare sand shrubby legume Eremosparton songoricum(Fabaceae) in Gurbantunggut Desert,China

Eremosparton songoricum,a rare and endemic sand dune plant,appears to be experiencing recruitment failure.The structure of five populations from the Gurbantunggut Desert,China,was investigated for recruitment patterns,and two of them were examined for flowering,pollination and seed germination limits on regeneration.The results showed that total 150 seedlings only occurred on line transects in riverside Dure population,but they all died half a month later;no seedlings occurred in other four hinterland desert populations indicating recruitment was a failure at all populations although flowers were plentiful.Reproductive success depends on pollinators.Nectar is ＇reward＇ for pollinators,with 0.06 μL-0.12 μL and 0.15 μL-0.35 μL per flower in Dure and Kabu populations,respectively,in continuously two secreting days.Spontaneous self pollination is rare with nearly zero fruit production.Geitonogamous self pollination is predominant with 14.47% fruit set.Seed mass in the riverside Dure population was significantly greater than that in other hinterland desert populations.Consequently,the Dure population exhibited a significantly higher germination rate（about 90%） than those in other populations（about 30%）.Results suggested that recruitment failure of E.songoricum is not due to flower shortage,pollination limitation,or poor seed germination but environmental pressure and/or human disturbance.

Species composition and diversity,and carbon stock in a dune ecosystem in the Horqin Sandy Land of northern China

In this study, we determined carbon allocation and carbon stocks in the plant-soil system of different dune ecosystems in northeastern China. We quantified the species composition, above and below-ground bio masses, and carbon stocks of three dune types （i.e. active dunes, semi-stabilized dunes and stabilized dunes） and their corresponding inter-dune lowlands （i.e. interdune lowlands of active dunes, interdune lowlands of semi-stabilized dunes and interdune lowlands of stabilized dunes） in the Horqin Sandy Land. The results showed that the succession series on interdune lowlands of the Horqin Sandy Land confirmed differences in species composition of the various dune types. Aboveground carbon （AGC） on the interdune lowlands of semi-stabilized dunes （33.04 g C/m2） was greater （P〈0.05） than that on the interdune lowlands of active dunes （10.73 g C/m2）. At the same time, the different dune types did not show any significant differences （/：〉〉0.05） in belowground plant carbon （BGC）. However, the percentage of plant BGC in interdune lowlands of active dunes （81.5%） was significantly higher （P〈0.05） than that in the interdune lowlands of semi-stabilized dunes （58.9%）. The predominant carbon pool in the study dune ecosystem was in the soil. It accounted for 95% to 99% of total carbon storage. Soil organic carbon （SOC） was at least 55% greater （P〈0.05） in the interdunes than in the dunes. Stabilized dunes showed at least a 37% greater （P〈0.05） SOC content than active dunes up to a 1-m soil depth. Meanwhile, SOC content of interdune lowlands of semi-stabilized dunes was greater （P〈0.05） than that of interdune lowlands of active dunes only up to a 20-cm soil depth. The dune ecosystem showed a great potential to store carbon when interdune lowlands of active dunes were conversed to interdune lowlands of semi-stabilized dunes, which stored up to twice as much carbon per unit volume as interdune lowlands of active dunes.