Grazing exclusion via fencing is widely acknowledged as an effective strategy for restoring soil organic carbon (SOC) levels in degraded grasslands worldwide. However, the contribution of microbial necromass to SOC dynamics following grazing exclusion remains inadequately addressed, particularly in alpine grasslands. In this study, we quantified soil microbial necromass C (MNC) and its proportional contribution to SOC across three alpine grasslands subjected to 0, 4, and 12 years of grazing exclusion on the eastern Tibetan Plateau. Four amino sugars, including glucosamine (GluN), galactosamine (GalN), muramic acid (MurA), and mannosamine (ManN) were employed as biomarkers to estimate MNC. The results showed that soil total organic C (TOC) increased by 58%-82% following grazing exclusion, with significantly higher TOC content in grassland restored for 12 years (GE12) than in unrestored grassland (GE0). Grazing exclusion did not alter the contents of GluN, GalN, or ManN. In contrast, MurA content in GE12 was significantly higher than that in grassland restored for 4 years (GE4). Across all three grasslands, fungal necromass C (FNC) represented an average of 84% of MNC, indicating that fungi represent the dominant source of microbially derived C. Although grazing exclusion induced increases of 21%-51% in MNC and 25%-49% in FNC, these shifts were not statistically significant. Bacterial necromass C (BNC) remained unchanged during the first 4 years of exclusion but increased significantly with continued exclusion. Soil physical properties and microbial biomass C were identified as key factors modulating MNC dynamics during grazing exclusion. The proportions of MNC, FNC, and BNC relative to TOC in GE4 and GE12 were generally lower compared to those in GE0, suggesting that grazing exclusion diminished the role of microbial necromass in SOC sequestration. The negative correlation between MNC/TOC and plant biomass further implied that plant-derived C may be more crucial for SOC accumulation than microbially derived C during grazing exclusion. In conclusion, our findings demonstrate a limited role of microbial necromass in SOC sequestration over the 12-year grazing exclusion period in Tibetan alpine grasslands.

The landscape ecotones at the edge of Poyang Lake Sandy Land are of critical for ecological conservation and restoration, and the spatiotemporal evolution of their location and structure indicating regional sand advancement and retreat. However, rapid changes in regional surface landscapes and complex environmental disturbances have hindered dynamic and quantitative assessments of ecotone positions and widths. This study aimed to precisely identify landscape ecotone widths and analyze their spatiotemporal variation characteristics. We focused on the ecotones between sandy land and adjacent landscapes (croplands, wetlands, and forests) at the landward edges of the Xingzi and Duobao Sandy Lands in the Poyang Lake region. An advanced remote sensing ecological index (ARSEI) was constructed, and five phases of imagery from 2000 to 2024 were applied to precisely identify the landscape ecotone width through piecewise linear fitting and habitat gradient change validation. We found that Xingzi Sandy Land's northern edge ecotone width ranged from 421 to 826 m, exhibiting a decreasing-increasing-decreasing trend. The central and southern edge ecotones were approximately twice as wide, with annual growth centrally and slow decrease southward. Duobao Sandy Land ecotone widths (279-746 m) were significantly smaller, showing initial decrease then later increase. Field investigations of vegetation and soil property factors confirmed that spatial positions and widths closely aligned with ARSEI-derived measurements. Pronounced sand retreat phenomena occurred in Xingzi's northern area and Duobao's southern area, suitable for natural restoration. The Xingzi's central and southern areas of ecotones require priority ecological restoration due to significant width fluctuations. Human activities (sand mining, industrial construction, tourism) must be strictly regulated in these areas.

Aerodynamic roughness (z0) reflects the extent to which surface roughness elements reduce wind erosivity, and accurate monitoring of z0 is crucial for soil wind erosion models. Spring is a period of high soil wind erosion risk in arid and semi-arid steppes in China. However, current z0 estimation models are mostly based on surface roughness features in summer and cannot represent actual spring surface conditions. Using four machine learning methods: eXtreme Gradient Boosting (XGBoost), K-Nearest Neighbors (KNN), Random Forest (RF), and Partial Least Squares Regression (PLSR), we evaluated the accuracy of z0 estimation models constructed based on photosynthetic vegetation (PV) and non-photosynthetic vegetation (NPV) parameters in spring (April-May). The NPV-based z0 model outperformed the PV-based z0 model, with the XGBoost_NPV-based z0 achieving the highest accuracy (R2 = 0.790, RMSECV = 0.113, rRMSECV = 0.452). From 2010 to 2022, daily spring z0 of Xilingol Steppe exhibited a decreasing trend, with a multi-year average of 0.38 cm. Spatially, z0 increased from southwest to northeast, and its stability ranked from high to low as: desert steppe, meadow steppe, typical steppe, and sandy steppe. These findings demonstrate the applicability of NPV parameters for estimating spring z0 and support long-term, large-scale monitoring of soil wind erosion.

Numerous woody plants regenerate shoots from roots and stumps after aboveground damage. Frequent disturbances (herbivory, cutting) in desert ecosystems make resprouting critical for plant survival and ecosystem sustainability, yet the adaptive mechanism of new shoots remains unclear. We measured leaf water potential, photosynthesis, and quantified water sources of four desert shrubs. The results showed that resprouting plants did not shift the root water uptake sources. Calligonum mongolicum, Hedysarum scoparium, and Tamarix chinensis mainly relied on deep soil water and groundwater, with a conservative water-use strategy. While Zygophyllum xanthoxylum displayed remarkable plasticity, switching between shallow and deep sources in response to seasonal changes and precipitation events. Specifically, following precipitation, its shallow use proportion increased sharply from 12%∼14% to approximately 50%. Compared with control plants, resprouting plants exhibited significantly higher leaf water potential (p < 0.05), photosynthetic rate, and transpiration rate. These findings suggest that resprouting shrubs adopt a prioritized recovery strategy in water transport and utilization, which confers a competitive advantage and promotes rapid regeneration. The change in water sources regulated stomatal conductance to coordinate the balance between carbon assimilation and water consumption, thereby affecting the water use efficiency of plants and overall water adaptability. Finally, the findings revealed that desert plants can rapidly regrow by competing for limited resources such as water and nutrients following external disturbances. This effectively enhanced the self-repairing potential of the damaged desert communities, maintained the stability of species diversity, and provided a scientific basis for the vegetation restoration and ecological restoration in arid areas.

In desert regions, precipitation is one of the significant water sources and a key driver of ecohydrological processes over a range of spatiotemporal scales. When precipitation infiltration was combined with the original soil water, the soil water and plant water use will experience significant dynamic changes, which play an important role in the stability and sustainability of the artificial vegetation. Therefore, soil water dynamics and water use strategies of Haloxylon ammodendron were studied by the hydrogen and oxygen stable isotope technique in this study. The results showed that precipitation in the desert soil was mainly in the form of piston flow, and the precipitation that led to the significant increase of infiltration and recharge was different in different precipitation events. The precipitation of 12.8 and 19.6 mm can make the surface soil water sufficient and continue to penetrate into the deep soil, and the duration of soil water response and the recharge depth were much longer and deeper than those for 4.4 and 7.8 mm events. In addition, the H. ammodendron mainly relied on stable and abundant deep soil water and groundwater. The water use source of H. ammodendron showed no significant response to 4.4 and 7.8 mm precipitation. However, a significant difference in water source proportion occurred before and after 19.6 mm of precipitation. The use proportion of shallow soil water increased from 10.7% to 24.2%, while that of groundwater decreased from 48.8% to 23.2%. Therefore, we concluded that precipitation levels have a major impact on soil water at various depths; in particular, heavy precipitation has a significant impact on deep soil water that deeply controlled the survival of the H. ammodendron plantation. These results offer an essential theoretical foundation for vegetation restoration and sustainability in arid regions.

Study region: At the southern edge of Badain Jaran Desert, China. Study focus: The mixed shrubs of Calligonum mongolicum and Nitraria sphaerocarpa are the common species in extreme arid areas. There are few studies on the water use and coexistence mechanisms of the two species. So we examined the water use strategies of these two species based on hydrogen and oxygen stable isotope technology, and the coexistence mechanism of the two desert plants was explored from the perspective of hydrological niche separation (HNS). New hydrological insights for the region: The N. sphaerocarpa had more root biomass in shallow soil than C. mongolicum, whereas the opposite was true in deep soil, indicating a root niche separation. Additionally, the C. mongolicum exhibited a significant dependence on deep soil water (about 26 %) and groundwater (over 30 %); while N. sphaerocarpa has a significant response to precipitation, its proportion of shallow soil water is more than 40 % after heavy precipitation events, in seasons with less precipitation, it relied on groundwater for survival. Both species had a dynamic HNS, the hydrological niche overlap index exhibited a decreasing and then increasing trend; but HNS was low during the dry season, indicating that HNS was affected by precipitation. We conclude that the main reason why the two species can coexist in arid regions is their HNS, which avoid competition for limited water resources.

Desertification is acknowledged as a significant global ecological challenge. In the current context of advancing ecological governance and sustainable development, it is imperative to explore optimal solutions that reconcile economic and ecological interests. This study examined the economically viable crop Jerusalem artichoke (Helianthus tuberosus L.) by selecting four varieties (Qingyu Nos. 1 to 4) for cultivation in the semi-arid sandy region of the Qinghai Plateau. This research analyzes and discusses the growth and development as well as the ecological adaptability of the various varieties, evaluating their feasibility for ecological restoration in high-altitude, semi-arid, sandy environments. The findings suggest that, under high-altitude and semi-arid conditions, these varieties demonstrate a spectrum of physiological and ecological adaptations, including alterations in organ allocation, limited vegetative growth, and modifications in root distribution. Notably, Qingyu Nos. 1 and 2 are more adept at thriving under cold and dry conditions, whereas Qingyu Nos. 3 and 4 are more suitable for cultivation in warmer and humid environments. This study offers valuable insights into crop cultivation in high-altitude, semi-arid, desert regions and proposes innovative strategies for the advancement of the local sand industry. The ecological restoration approach that employs these crops for sand stabilization enhances the transformation of ecological benefits.

Grazing removal is a globally implemented strategy for rehabilitating degraded grasslands. However, its effect on soil organic carbon (SOC) fractions remains inadequately understood. Herein, the SOC pool was divided into coarse particulate OC (cPOC), free fine POC (fPOC), intra-microaggregate fine POC (iPOC), and mineral-associated OC (MAOC) by a physical fractionation scheme to quantify the changes in SOC after 4 and 12 years of grazing removal in Tibetan alpine meadows. The results demonstrated that OC associated with macroaggregates (MA) was more sensitive to grazing removal than that within microaggregates (MI). Grazing removal enhanced the contents of fPOC-MA (27–42

Abstract. Understanding river water age and its controlling factors are fundamental for comprehending catchment hydrological and biogeochemical processes. However, how do landscape characteristics and climate properties control the spatiotemporal heterogeneity of riverine water age remain to be further clarified in subtropical headwater catchments. This study used stable isotopic ratios (δD and δ18O) from five contrasting headwater catchments. The study explored time-variable young (Fyw) and new (Fnew) water fraction among five contrasting headwater catchments from the upper reaches of Xiu River, located within the Poyang Lake catchment of South-Central China using stable isotopes (δD and δ18O) from 2021 to 2023. The isotopic compositions of precipitation exhibited greater fluctuations than those of river water from five sub-catchments. The lower slopes (3.78 to 6.63) and intercepts (-13.12 to 2.65) of linear regression correlations between δD and δ18O were observed in river water compared to the global and local meteoric water lines, indicating significant evaporation effects on river water. The young water fraction (Fyw) showed considerable spatial variability ranging from 0.07 to 0.21 among five sub-catchments, suggesting the dominant recharge of groundwater to the river. The pronounced temporal variations of Fyw highlighted its susceptibility to short-term hydroclimatic change. Random forest models revealed that precipitation (25.48±5.41 %) and potential evapotranspiration (27.84±6.62 %) were the primary drivers for young and new water generation. Furthermore, Fyw was significantly influenced by upstream inflows (24.21±0.71 %), whereas Fnew was more susceptible to the influence of percentage of forest (22.63 %) and cropland (29.85 %). Shapley Additive Explanations reveal a significant negative correlation between river area and Fyw, and a significant positive correlation between agricultural area proportion and Fnew. Combined with the dynamic variations in the Fyw and Fnew, these results indicated that the regulatory function of riparian zones played a crucial role in young water generation, while land use changes significantly altered the process of new water generation. Our findings suggest that intensified evapotranspiration and increased precipitation will significantly impact the generation of riverine young and new water in the context of global warming and land use type changes.

Water is the most critical limiting factor for plant survival,and the study of water utilization in desert plants has become the key to ecological protection and vegetation restoration programs.This study focused on three typical sand-fixing plants:Pinus sylvestris,Populus simonii,and Hippophae rhamnoides,in the sandy land on the east shore of Qinghai Lake,as the research material.The potential water source(varying levels of soil water)and the primary water sources for plants under the influence of micro-topography were analyzed by hydrogen and oxygen stable isotope technology(δ18O and δD)and the IsoSource isotope mixing model.The results show that:(1)the soil water content demonstrated micro-topography-based differences,which manifested as the soil water content on the windward slope being higher than that on the top of the sand dunes and the middle of the windward slope and the soil water content was at its highest in September.(2)the δ18O value of the xylem water varied in the tree species under different micro-topographic conditions.The δ18O values of P.sylvestris in the lowland of the windward slope were the lowest,while those of H.rhamnoides and P.simonii were the least in the middle of the windward slope.(3)marked seasonal variations were observed in the primary sources of water for different plants.In June,P.sylvestris and H.rhamnoides used deep soil water as the major source under varied micro-topographic conditions,while P.simonii mainly used deep soil water at the top of sand dunes.The soil water of the middle-layer was utilized more in the middle and lowlands of the windward slope.Still,with the increase of precipitation,various tree species turned to mainly using the shallow and middle soil water in September.In summary,the water use patterns of sand-fixing plants in the alpine sandy land were influenced by micro-topographic conditions,and varying species showed different degrees of response to precipitation.

In the context of increasing global carbon emissions and relative water scarcity, it is of great significance to study the relationship between climate change and carbon-water coupling. This study aims to investigate the carbon-water process of at alpine desert at the east shore of the Qinghai Lake in the northeastern of Qinghai-Tibet Plateau. The results indicated that (1) the annual average values of net ecosystem exchange (NEE), evapotranspiration (ET), and water use efficiency (WUE) in study area were -696.9 g C·m-2, 834.07mm, and 0.84 g C·kg-1·H2O , respectively. (2) At the annual scale, NEE is mainly influenced by air temperature (Ta) and precipitation (P), while ET and WUE are dominated by Ta and soil temperature (Ts), and Soil water content (SWC) has relatively little influence on NEE, ET and WUE. (3) On the seasonal scale, NEE and ET showed the strongest performance in summer, followed by fall, spring, and winter, and Ta and vapor pressure deficit (VPD) were the main factors affecting the seasonal variation of NEE, ET, and WUE. (4) On the diurnal scale, Ta and VPD are the main influences on NEE and ET, and Ta and SWC are the main influences on WUE. P has a significant increase in its contribution to NEE, ET and WUE. Above all, the findings demonstrated that the alpine desert exhibits a strong carbon sink pool. We concluded that thermal conditions (Ta, Ts20, Ts40) were more crucial than moisture conditions (VPD, SWC20, SWC40) for carbon and water processes in alpine desert ecosystem. Given changeable of climate variability and localized thermal and hydrological conditions in future, reducing ET would be an approach that works well to improve WUE, meanwhile, the selection of appropriate species for water and carbon sequestration would be an effective way to maintain the ecological balance of alpine desert ecosystems.

Different types of dunes cause habitat differences, which can affect vegetation growth. In turn, water utilized by vegetation leads to the differential distribution of soil moisture in different dunes. However, vegetation–soil dynamics in the alpine desert of the Qinghai–Tibet Plateau remain poorly understood. We chose the largest section of desert along the eastern shore of Qinghai Lake as a study area to test the hypotheses that plant community characteristics and soil physicochemical properties show differences in different sand-binding communities, in addition to soil moisture content, based on methods of field investigations and in situ observations. The main results were as follows:1) Plant community species diversity and herb coverage increased with the stabilization status of dunes; meanwhile, coverage increased with the age of the added artificial semi-fixed dunes. 2) Surface deposits were mainly composed of medium sand, leading to low organic matter and nutrient content in the study area; this being different from other deserts in northern China. 3) Soil moisture’s seasonal variation was consistent with rainfall seasonality and lacked significant interannual differences, while its vertical distribution was influenced by precipitation infiltration. 4) Soil crust forms beneath specific species, such as leguminous plants in the study area, which should be effective at preventing wind erosion. Our findings will facilitate a mechanistic understanding of plant–soil–water relationships in alpine deserts and provide timely information for screening introduced species for enhancing sand-fixation effectiveness.

The processes of species obtaining water resources are crucial to evaluate the adaptability of plantations, which can affect the establishment and survival of restored ecosystems and functions of water-limited ecosystems. However, there are still limitations in understanding water use patterns of different four plantations (Populus sylvestris, Salix cheliophe, Hippophae rhamnoides and Artemisia ordosica) in the Qinghai Lake basin. Stable isotopes of xylem water of four individual species were analysed at different dunes located at the eastern shore of Qinghai Lake in 2018 and 2019. The purpose of this study was to explore potential water sources used by different life form plants, to identify whether the soil moisture content and root distribution determined the plants water use patterns. Results from the MixSIAR models showed that all species mainly uses three levels of soil water, but they extracted soil water from different layers in different growing seasons among species. All species primarily depended on water from upper soil layers at the early growing stage, but P. sylvestris and S. cheliophe also absorbed much proportion middle and deep soil layers’ water in dry year of 2019. All four species shift to use middle or deep soil layer water rather than shallow water in July with the most rainfall and soil water content. However, it was only used by P. sylvestris and H. rhamnoides in 2018. In all, seasonal water use pattern of different species was affected by soil water content, soil texture and root distribution. Compared with moratorium plantations such as S. cheliophe, mixed afforestation of P. sylvestris and H. rhamnoides maximized of soil water sources absorbed by the plants. The study can shed light on plant-water relationships to facilitate the woody species for afforestation and desertification restoration management in the semi-arid desert ecosystem.

[Objective] The temporal-spatial variation of soil moisture and its influencing factors for semi-arid alpine desert communities of Hippophae rhamnoides were studied in order to provide a scientific basis for the restoration of ecosystems of Qinghai Lake and semi-arid deserts. [Methods] H. rhamnoides plantations were taken as the research object. In the growing seasons of 2020 and 2021, vegetation investigation and soil sampling was carried out on the H. rhamnoides communities in the Ketu sandy land on the eastern shore of Qinghai Lake. Through the use of classical statistical methods, the vegetation characteristics of H. rhamnoides and the temporal-spatial changes of soil moisture in different dune geomorphic parts were comprehensively analyzed. [Results] ① In terms of vegetation growth, plant height of H. rhamnoides planted in 2008 (08SJ) was the tallest, followed by plant height in 1987 (87SJ). Plant height in 2015 (15SJ) was the shortest. Vegetation coverage followed the order of 87SJ>15SJ>08SJ. ② Soil moisture content of H. rhamnoides communities followed the order of 87SJ>08SJ>15SJ. Among these communities, the soil moisture contents of the H. rhamnoides planted in 1987 (87SJ) and the H. rhamnoides planted in 2015 (15SJ) were the highest on the windward slope, while the soil moisture content of the H. rhamnoides planted in 2008 (08SJ) reached the maximum value on the leeward slope; ③ Soil moisture content showed obvious seasonal variation, and the soil moisture content was the lowest in the vigorous growth period, and highest at the end of the growing season. ④ Soil moisture content was highest in the 0—20 cm soil layer, and changed little below a depth of 60 cm. [Conclusion] Vegetation distribution pattern, precipitation, and its seasonal changes were the main factors affecting the temporal-spatial variation of soil moisture under H. rhamnoides communities in a semi-arid alpine desert ecosystem.

土地沙化是青海高原面临的最严重的生态问题之一.沙化土地主要分布在柴达木盆地、共和盆地、青海湖环湖地区、黄河源区和长江源区.其中青海湖周边地区沙漠化土地是生态建设的重点和难点.因此,在此区域开展治沙造林模式示范,人工植被与气候、土壤环境的相互作用机制等研究,不仅对青海湖周生态环境保护和建设有重要意义,而且对青海湖区社会经济发展的影响深远,同时可以为高寒沙区的防沙治沙提供技术支撑和科学依据,并为沙漠化防治规划提供理论支持.

Numerous crucial paleoclimate records in monsoon regions depend on past precipitation isotopes as proxies for hydroclimate; however, the relationship between climatic variability and precipitation isotopes remains poorly understood. In this study, we investigated key climatic drivers from local to regional scales using 7-year-long daily summer precipitation isotopes in the Qinghai Lake watershed of the northeast Tibetan Plateau, located in the margin of summer monsoon extent. Results showed that daily precipitation δ 18 O and δ 2 H exhibited intra-seasonal fluctuation from 2012 to 2018 characterized by low isotopic values in July (e.g., δ 18 O = − 10‰) and high values in June (e.g., δ 18 O = − 6.7‰). Moisture source analysis via Hybrid Sing-Particle Lagrangian Trajectory indicated that the primary moisture of Qinghai Lake was mainly derived from northwestern inland regions, North China, and South China across seasons with high specific humidity and trajectory frequency, having a great influence on the isotopic patterns in precipitation across seasons. Moreover, convective activities in the primary moisture source regions, shown by outgoing longwave radiation and specific humidity along back trajectory, played a crucial role in controlling the seasonal variability of precipitation isotopes. These effects could be closely associated with the upstream convective intensity over the moisture sources or the changes of moisture sources during the observation periods. Interannual precipitation δ 18 O variation was significantly correlated with the indices of the El Niňo Southern Oscillation ( r = 0.63, p < 0.1), with high precipitation δ 18 O value in the dry El Niňo year of 2015. Our findings suggested that precipitation isotopes in the Qinghai Lake watershed represented a spatial–temporal integrative indicator of precipitating processes and convection activity, providing the interpretation of paleo-isotope data in the regional hydroclimate variability across monsoon-affected regions.

Alpine revegetated dunes have been barely researched in terms of morphological change and migration within its regional aeolian environments. To reveal the sand-fixing and land-reforming mechanisms of artificial vegetation, we observed the morphology and migration of four dunes with four revegetated types (Hippophae rhamnoides Linn., Salix cheilophila Schneid., Populus simonii Carr., and Artemisia desertorum Spreng.) using unpiloted aerial vehicle images and GPS (global positioning system) mapping in 2009 and 2018. Spatial analysis of GIS (geographic information system) revealed that the revegetated dunes exhibited a steady progression from barchan dune shapes to dome or ribbons shapes mainly through knap planation, wing amplification, and slope symmetrization. Generally, conditions of northern aspects, smaller slope degree, and larger altitude of unvegetated dunes would suffer more serious wind erosion. The southward movement of dune wings with a migration speed of 2.0–5.0 m/a and the alternating motion of sand ridges in eastwestern directions led greater stability in revegetated dunes. The moving distances of revegetated dunes remarkably changed in patterns of quadratic or linear function with depositional depth. Compared with unvegetated dunes, the near-surface wind velocity of revegetated dunes decreased by 20%–30%, which led to heavy accumulation in low-flat dunes and erosion in high-steep dunes, but all vegetation species produced obvious sand-fixing benefits (100%–450% and 3%–140% in the lower and higher dune scales of revegetated dunes, respectively) with decreasing sand transport rates and increasing coverages. In practice, the four vegetation species effectively anchored mobile dunes by adapting to regional aeolian environment. However, future revegetation efforts should consider optimizing dune morphology by utilizing H. rhamnoides as a pioneer plant, S. cheilophila and P. microphylla in windward and northward dune positions, and A. desertorum in a sand accumulative southward position. Also, we should adjust afforestation structure and replant some shrub or herbs in the higher revegetated dunes to prevent fixed dune activation and southward expansion.

Afforestation is an effective measure for ecological restoration in the desert ecosystem. The long-term water use efficiency (WUE) of leaves is an important indicator for evaluating the water adaptation strategy of sand-fixing species. However, the WUE of typical sand-fixing plants in the alpine desert and its responses to local climatic, micro-geomorphology, environmental conditions and nutrient limitations are still unclear. In this study, sand-fixing vegetation community along a revegetation chronosequence (Hippophae rhammoides planted on dunes in 1987, 2008, and 2015, respectively. H. rhammoides with the longest recovery period were defined as mature plantations, and the shortest recovery period were defined as juveniles.) at the alpine desert at the eastern shore of the Qinghai Lake were used as the research plots. Stable carbon isotope was used to evaluate species WUE. The results showed that: (1) the δ13C values of H. rhammoides showed a decreasing trend as plants grew. The seasonal δ13C variation was mainly affected by average relative humidity (MRH). (2) The δ13C in the dunes revegetated in 2008 and 2015 were significantly higher than that in 1987 at the windward slope (P < 0.05). The values of δ13C had various responses to the available soil water under the influence of topography, and soil water content was the key factor for the WUE of individuals in communities. There was a significant negative correlation between the ratio of carbon and nitrogen content in H. rhammoides leaves and WUE. The research indicated that mature plantations had adopted a more stable water use pattern than the juveniles, which provide an effective insight for ecological restoration in fragile ecological regions.

生态保护和建设是青海的立省之本,而防沙治沙是青海生态保护建设的重要内容.为提升青海湖周边地区防沙治沙能力,青海大学农林科学院承担的"青海湖流域沙化土地综合治理技术集成示范"项目,在青海高寒沙区首次建立了"生物沙障+乔木+灌木+草本+中草药植物"综合防沙治沙试验示范区,流动、半固定沙丘区域面积缩小,固定沙地得到了快速、有效的恢复,生物多样性指数提高.