Urban-rural inequality has become a major challenge to sustainable regional development, yet ecosystem services (ES) have rarely been examined from the perspective of the urban-rural gradient. Using the Loess Plateau (LP) as a study area, this research developed an urban-rural classification system at the township scale based on administrative codes and assessed habitat quality (HQ), water yield (WY), carbon sequestration (CS), and soil conservation (SC) under three future scenarios (SSP126, SSP245, and SSP585) for 2030, 2050, and 2070 based on the InVEST model. Trade-offs and synergies among ES were further analyzed using the geographically weighted regression and the production possibility frontier framework. The results show that: (1) Cropland declined and urban land expanded under all scenarios, with the largest expansion occurring in mixed rural towns under SSP585. (2) The HQ and CS generally decreased, whereas WY was the most climate-sensitive service and SC showed strong scenario dependence. (3) Along the urban-rural gradient, urban towns consistently exhibited the lowest ES levels and the greatest ecological decline, with the proportion of declining HQ reaching 51.05% under SSP585. (4) Most ES pairs were dominated by synergies, especially HQ-CS, HQ-SC, WY-SC, and CS-SC, while trade-offs were mainly concentrated in HQ-WY and WY-CS. These findings show that urbanization intensifies ecological inequality along the urban-rural gradient, with urban towns and mixed transitional areas facing the greatest pressure. This study provides a spatially explicit basis for differentiated ecological protection and land-use management in ecologically fragile regions.

The Qaidam Basin, a typical alpine arid inland basin on the northern Qinghai-Xizang Plateau, China, hosts wetland ecosystems that are strongly constrained by topography and extreme climate. These ecosystems exhibit pronounced spatiotemporal heterogeneity and fragmented distribution patterns, rendering them highly sensitive to environmental change. This study integrated Sentinel-2 remote sensing imagery with the SedInConnect model to delineate wetland patch distributions and calculate the Index of Connectivity (IC) values across the basin. Based on IC values, we stratified field sampling sites into high-, moderate-, and low- connectivity gradient groups to analyze the relationships among plant community characteristics, vegetation spatial patterns, and wetland connectivity in the Qaidam Basin. Partial Least Squares Path Modeling (PLS-PM) was further employed to quantify the driving mechanisms underlying wetland vegetation characteristics. The results revealed that wetland connectivity across the basin was generally low, with IC values up to 1.32 and displaying a west-to-east decreasing gradient. The west and northwest were characterized by relatively continuous high-connectivity wetland networks, while fragmented and low-connectivity wetlands predominated in the east and southeast. Connectivity regulated wetland vegetation patterns primarily by affecting patch size, fragmentation, and internal adjacency. High-connectivity areas had higher class area (CA), largest patch index (LPI), and area-weighted mean patch size (AREA_AM) than low-connectivity areas. Connectivity had the strongest effect on vegetation coverage, which declined sharply from 87.577% in high-connectivity areas to 12.152% in low-connectivity areas. Meanwhile, species diversity showed a moderately negative response to connectivity changes, whereas species evenness remained relatively unaffected. PLS-PM explained 78.300% and 67.500% of the variance in vegetation community and vegetation pattern, respectively. Climate played a dominant role in shaping vegetation characteristics, with significant negative effects on both vegetation community and pattern. Topography influenced vegetation indirectly through climate, and connectivity was influenced by both drivers and exerted positive effects on vegetation community and pattern. This study reveals the multi-pathway driving mechanisms underlying vegetation pattern formation in alpine wetlands, providing a theoretical foundation and decision-support framework for the scientific conservation and adaptive management of wetlands in the Qaidam Basin.

Meteorological factors are the key drivers of ecosystem structure and function in arid regions.In the context of global climate change,rising temperatures,altered precipitation patterns,and frequent extreme events may further threaten the ecological security of arid regions.Enhanced meteorological monitoring serves as a fundamental prerequisite for sustainable management in arid areas.This dataset encompasses long-term observation data spanning from April 1,2018,to December 31,2023,collected from the national desertification land enclosure and protection area in the northern part of Linze County,Gansu Province.It provides a systematic analysis of the temporal dynamics of microclimate variables and soil temperature and moisture content at daily,monthly,and annual scales.Using the HOBO U30 automatic weather station and multi-parameter sensors,high-resolution data were obtained for air temperature,precipitation,relative moisture content,as well as surface soil temperature and moisture content in the microhabitats of Nitraria sphaerocarpa,Reaumuria songarica shrubs,and in bare land,were obtained.The dataset applies a three-tier quality control system,including instrument calibration,real-time threshold monitoring,and manual cross-checking,ensuring the accuracy and continuity of key variables such as air temperature,precipitation,and soil temperature and moisture content.This dataset reveals the dynamic patterns of microclimate variables in the grazing-prohibited wind-blown sand protection area,quantifies the impact of shrub presence and species differences on ground soil temperature and moisture content,and provides a scientific basis for evaluating the effectiveness of desertified land protection measures.The establishment and public release of this dataset aim to offer long-term,high-quality data for characterizing meteorological conditions in typical desert ecosystems of arid and semi-arid regions.

Ecosystem management in hyper-arid endorheic basins often faces challenges in achieving sustainable development goals, as restoration efforts tend to prioritize spatial expansion over ecohydrological boundaries. A key challenge is that without ecohydrological boundaries to guide spatial decisions, restoration efforts risk over-stressing groundwater resources in some areas while missing recovery opportunities where most needed. This study introduces an innovative method that integrates ecohydrological limits into the restoration of groundwater-dependent vegetation (GDV) in the middle and lower reaches of the hyper-arid Shule River Basin (SRB) in northwestern China. By applying Eagleson's ecohydrological model and the ordered weighted averaging methods, we estimated the vegetation-water relationship in the region. The results reveal that 9.64% of the entire main area has actual vegetation coverage (Ma) exceeding the optimal threshold (M0), i.e., surpassing the ecohydrological boundary, while less than 1.69% of the total area falls below optimal levels. These results challenge the assumption that GDV restoration opportunities are widespread; instead, most areas are near equilibrium. Groundwater is shallower (3.79 m) in above-optimal areas, yet GDV coverage in these areas is more sensitive to groundwater decline, showing a steeper decrease with falling water table than in below-optimal areas. Priority zones for restoration or conservation vary with decision scenarios, but consistently concentrate in the western and southeastern basin. Our findings suggest that restoration approaches may need to shift from extensive expansion to precision-based, adaptive strategies, with model-informed, scenario-dependent prioritization of targeted interventions in high-priority areas and protective measures in vulnerable low-priority regions for sustainable GDV restoration.

Understanding how irrigation practices interact with soil texture and influence microbiomes and nutrient cycling is critical for improving soil fertility and ecosystem sustainability in arid regions. The aim of this two-year field study was to investigate the effects of different modes of irrigation, namely flood, combined, and mulched drip irrigation, on microbial ecological adaptations and nutrient sequestration in sandy, sandy loam, and loam soils. Mulched drip irrigation significantly enriched soil carbon (17.78 %-23.58 %), nitrogen (30.32 %-57.89 %), and phosphorus (23.07 %-26.59 %) compared to flood irrigation, with peak levels found in loam. The most pronounced increases in microbial alpha-diversity induced by mulched drip irrigation occurred in loam, exceeding those in sandy soils by 9.54 %. Microbial beta-diversity was significantly affected by irrigation solely in sandy soils. Compared to loam, sandy soils exhibited a 4.70% higher enrichment of copiotrophic taxa and a 13.46% smaller reduction in oligotrophs under mulched drip irrigation. Mulched drip irrigation increased the complexity of the microbial network but decreased its stability. An elevated clay content enhanced complexity without reducing stability. Furthermore, mulched drip irrigation with loam maximally enriched carbon-assimilating microbes (69.11 %) and nitrogen-cycle genes (51.72 %), but minimally enriched metabolism-related bacterial functions (6.71 %). We revealed that irrigation, soil texture, and their interactions explained 55.59 %-68.96 % of the microbial assembly and functional variation. The results demonstrated that microbial assembly and functions driven by the irrigation-texture interactions serve as the key mediators of carbon, nitrogen, and phosphorus sequestration. Our findings extend insights into the microbiological driving mechanism of soil nutrient sequestration in arid agricultural ecosystem.

Defining precise ecological boundaries and setting clear hydrological benchmarks are critical for achieving sustainable management of groundwater-dependent vegetation (GDV), which plays a vital role in both ecologically significant and highly fragile ecosystems. However, accurately identifying these thresholds remains a complex task. This study applied a space-for-time substitution approach to investigate the eco-hydrological thresholds governing vegetation transitions from GDV to non-GDV states in the hyper-arid Shule River Basin of northwestern China. Extensive vegetation surveys were conducted across approximately 30,000 km2, encompassing diverse environmental gradients within the study region. The survey included 256 systematically sampled plots to ensure robust data representation. Using a combination of diversity indices (species, functional, and phylogenetic), cluster analysis delineated five distinct vegetation communities, with altitude and water table depth (WTD) emerging as the strongest drivers of community composition. Threshold Indicator Taxon Analysis (TITAN) identified twelve plant species—five responding negatively and seven positively to WTD gradients—as effective indicators for distinguishing between GDVs, non-GDVs, and their transitional states along hydrological gradients. The study revealed critical transition zones at WTD ranges of 9.16 to 11.04 m, with a 90% confidence interval extending from 3.79 to 15.41 m. These thresholds are intricately linked with the varying adaptive capabilities of the indicator plant species to WTD gradients, marking the hydrological boundaries between GDVs and non-GDVs. The shallower and deeper zones indicate the niche optima WTD for the GDVs and non-GDVs, respectively. Thus, for practical groundwater regulation, managers should interpret the thresholds by incorporating both the biotic indicators and their associated WTD intervals into adaptive management strategies. This study presents a reproducible TITAN-based methodology for determining dryland vegetation thresholds, with the identified eco-hydrological thresholds offering valuable scientific insights for regime-shift warning systems and conservation planning, and informing sustainable groundwater management strategies in arid regions globally.

Long-term desert reclamation in oasis agroecosystems profoundly alters soil conditions and microbial processes; however, its impacts on the microbial drivers of nitrous oxide (N2O) production remain unclear. Here, we investigated the effects of different durations of desert reclamation (0, 24, and 54 years since conversion from native desert to irrigated cropland) on N2O production and its pathways by combining a dual-isotope (15N-18O) labeling technique with molecular approaches. Continuous reclamation decreased soil bulk density and pH, but increased soil moisture, ammonium nitrogen (NH4+-N), nitrate nitrogen (NO3--N) and soil organic matter (SOM). Microbial biomass and enzyme activities (ammonia monooxygenase (AMO); hydroxylamine reductase (HyR); nitrate reductase (NR) and nitrite reductase (NiR)) were enhanced, accompanied by higher potential nitrification and denitrification rates (PNR and PDR). Gene abundances of amoA-AOA, amoA-AOB, nirK and nirS increased with reclamation age, with amoA-AOA and nirK remaining dominant within their respective guilds. Cumulative N2O production increasing from 5.1 μg kg-1 in unreclaimed soil (Till0) to 73.0 μg kg-1 after 54 years of reclamation (Till54). Pathway partitioning further showed a shift from nitrifier nitrification (NN; 41.31-61.48% in Till0) to greater contributions of nitrifier denitrification (ND; up to 53.10%), heterotrophic denitrification (HD; 28.72-32.38%), and nitrification-coupled denitrification (NCD; up to 30.21%) in reclaimed soils. Partial least squares path modeling revealed that soil properties and nitrifier gene abundance exerted the strongest direct and total effects on N2O production, with NH4+-N, microbial biomass carbon (MBC), soil moisture content, and AMO activity being the strongest predictors. Together, these results indicate that reclamation age links to N2O production pathways through a soil-development cascade: reduced compaction and pH, greater moisture and SOM accumulation, increased mineral N and microbial biomass, and expansion of amoA- and nir-bearing functional guilds. This cascade shifts N2O production from NH4+-driven nitrifier nitrification in native desert soil toward denitrification-dominated and coupled pathways in reclaimed oasis agroecosystems.

Microhabitat heterogeneity plays a crucial role in shaping plant water use strategies and ecophysiological processes in arid ecosystems, yet little is known about the coupled response of leaf water isotopes and photosynthetic physiology to such fine-scale environmental variation. This study employed stable isotope tracing (δ2H and δ18O) and photosynthetic gas exchange measurements to investigate water sources, leaf water isotope dynamics, and photosynthetic traits of the dominant desert plant Haloxylon ammodendron across different microhabitats (flats and dunes) within the oasis-desert transition zone of the Hexi Corridor. In both microhabitats, H. ammodendron relies on groundwater as its primary stable water source, but the depth of soil moisture uptake shows significant differentiation. This differentiation is tightly coupled with seasonal trajectories of leaf water isotope enrichment (Δ2H, Δ18O): the flat habitat exhibits a “high in spring, low in summer” pattern, while the dune habitat shows a “low in spring, high in summer” pattern, accompanied by opposed photosynthetic physiological responses. Notably, the rate of leaf water isotope enrichment peaks at noon when stomatal conductance is at its lowest, confirming the nonlinear regulation of transpiration fractionation by stomatal behavior. Air temperature is the dominant meteorological driver of Δ18O variation, yet habitat specificity is pronounced—a positive correlation exists in flat habitats, while a negative correlation prevails in dune habitats. Hydrogen isotope enrichment, however, is not directly regulated by meteorological factors. Structural equation modeling quantified that xylem water isotopes directly govern leaf water isotopes (path coefficients 0.35–0.58), while soil water isotopes exert indirect regulation. Environmental factors primarily influence leaf isotopes by modulating soil moisture. This study elucidates the coupled regulatory mechanism by which microhabitat heterogeneity drives plant water uptake, leaf isotope enrichment, and photosynthetic physiology, providing important insights into how plants adapt to heterogeneous arid environments.

Arachnids constitute the primary predatory arthropod taxa in desert ecosystems, and as predators, they play a crucial role in maintaining and facilitating the coexistence of arthropod diversity within these ecosystems. In light of this, this study utilises dynamic monitoring data from 72 uniform 8 m × 8 m grids in the Gobi Desert spanning from 2012 to 2020. The aims are to analyse the spatiotemporal patterns of composition and diversity in arachnid arthropod communities, and to ascertain the impact and regulatory mechanisms of precipitation, temperature, and shrub interactions on arachnid arthropod assemblage. The key findings are as follows: (1) Karschiidae, Phalangiidae, and Gnaphosidae constitute the main arachnid family in the Gobi Desert, with accounting for 17.78%, 27.29%, and 27.35%. (2) There is significant annual variation in the composition of the arachnid community, and increases in precipitation boost the population of Karschiidae and Phalangiidae, thereby enhancing the abundance and diversity of arachnids. (3) The spatial autocorrelation distance between arachnids and major families varies seasonally and annually, with significant positive correlations observed between arachnid communities and the abundance of dominant families captured within the ranges of 9.0–30.0 m and 5.1–48.9 m. (4) There is a significant positive correlation between annual precipitation and the activity density of Karschiidae, Gnaphosidae, and Lycosidae; in contrast, the annual average temperature is only significantly positively correlated with the activity density of Gnaphosidae. The coverage of Nitraria sphaerocarpa demonstrates a stable positive correlation with the number of individuals in the arachnid community during wet years (2012–2015, 2020), whereas the influence of Reaumuria songarica exhibits interannual specificity, showing a significant positive correlation only in 2013 and 2016. In summary, changes in climate, vegetation, shrubs, and soil environment strongly affect the spatiotemporal distribution pattern of arachnids in the Gobi Desert.

The exploration of sustainable water resource development is pivotal for ensuring regional economic and social advancement,as well as maintaining ecological balance.However,scant research has holistically evaluated ecological,living,and production water uses through the"community of life"lens.This study developed a sustainable water resource utilization(SWRU)evaluation index system for water resources in the Gansu region of Qilian Mountains from 2000 to 2023.We adopted the"three-life"water use approach within the"community of life"and conducted a complete evaluation of the existing state of SWRU in the study area.We further developed a simulation model using system dynamics(SD)approaches for status quo,economic,and comprehensive multi-scenario forecasting,and employed the obstacle degree model to determine the parameters influencing SWRU.The findings revealed that the SWRU in the Gansu section of Qilian Mountains has advanced from a basic phase(0.438)to a commendable level(0.614),with a spatial distribution of"high in the west and low in the east".The SD simulation results indicated that the comprehensive scenario achieves the highest SWRU value(0.638),outperforming the economic(0.636)and status quo(0.630)scenarios.In the short term,a comprehensive scenario can support regional sustainable development;however,it has the potential to exacerbate the supply-demand conflict in the long term,necessitating additional refinement of the water resource allocation system.Proportion of ecological water consumption(obstacle degree of 14.388%),gross domestic product(GDP;12.475%),and total water resources(12.019%)have been highlighted as the primary obstacle factors on SWRU.Future strategies should focus on optimizing resource allocation to provide a high-quality ecological product supply,as well as merging ecological preservation with industrial advancement to support the long-term synergistic development of the living community.

Groundwater-dependent vegetation (GDV) plays a critical role as a natural barrier against aeolian erosion in dryland ecosystems. Despite its ecological significance, the full extent of GDV's functions remains not yet fully understood due to limitations in field data availability, spatial variability, and intricate groundwater-vegetation dynamics. This study employs machine learning techniques to distinguish GDVs from non-GDVs in the middle to lower reaches of the hyper-arid Shule River Basin (China), generating a comprehensive GDV map. Additionally, using the revised wind erosion equation model, we quantified their sand fixation capacity (represented by sand fixation amount and rate) over the period 2011-2022. Our findings reveal that GDVs, occupying a larger area than non-GDVs, play a stabilizing and pivotal role in sand fixation by contributing over 65% of the region's vegetation total sand fixation amount. Specifically, GDVs' average annual fixation amount (418.18 t) and rate (5.10%) both substantially outperform those of non-GDVs (207.93 t and 2.66%, respectively). Groundwater availability exerts a substantial influence on GDVs' sand fixation amount, as indicated by the significant negative correlation between groundwater depth and sand fixation amount (r = -0.37, p < 0.05). Certain deep-rooted species (e.g., Tamarix ramosissima, Populus euphratica) demonstrate exceptional sand-fixation ability, as evidenced by the abundant fine sediments trapped under their canopies. The study underscores the importance of prioritizing the identification and preservation of large, high-functioning GDV units. By strategically leveraging GDV's inherent ecological advantages, this approach provides a sustainable pathway to effectively combat desertification and enhance ecosystem resilience in hyper-arid regions.

Understanding soil nitrogen cycle processes and their responses to climate change under human influence represents a significant knowledge gap in refining land management and enhancing ecosystem functionality. This study aimed to investigate how soil temperature and moisture fluctuations affect soil nitrification, ammonification, and mineralization processes across different land-use types, and to explore the regulatory roles of human activity intensity and soil properties. Through field sampling and laboratory incubation experiments, we examined the responses and mechanisms of nitrogen nitrification, ammonification, and mineralization to soil temperature-moisture changes across four land-use types (Gobi desert grasslands, artificial sand-fixing shrubs, poplar shelterbelt forests, and reclaimed farmlands) in a typical arid region of northwest China. Increased soil temperature and moisture synergistically enhanced net nitrification and mineralization rates while concurrently suppressed net ammonification. Land-use type is the dominant factor regulating nitrogen cycle processes and their response to soil temperature and moisture. Nitrogen mineralization was primarily driven by nitrification and decoupled from ammonification. Moderate human activity intensity enhanced temperature-moisture sensitivity of nitrogen nitrification and mineralization. Importantly, land-use types and soil microclimate changes influence nitrogen mineralization processes and their climatic sensitivity through direct effect and, predominantly, through the mediation of key soil attributes such as texture and nutrient availability. Our findings conclude that optimizing land management and soil temperature-moisture regulation based on land-use types is crucial for enhancing nitrogen mineralization processes in arid ecosystems, and that high-intensity human activities should be avoided to prevent negative impacts on nitrogen mineralization.

Green manure coverage not only improves soil conditions and enhances soil fertility but also exerts significant effects on soil fauna diversity and ecosystem service functions. However, studies on the effects of manure-maize intercropping systems during both mulching and non-mulching periods on the trophic structure and functional roles of soil fauna remain limited, particularly in desert agricultural ecosystems. Accordingly, this study was conducted in the Zhangye Oasis, located in the arid region of northwestern China, using trap methods to systematically examine the effects of maize and green manure intercropping on soil fauna communities during both the green manure mulching and non-mulching periods. The results showed that: (1) During the green manure mulching period, the activity densities of macrofauna and mesofauna in maize and green manure intercropping fields were significantly higher than those in monoculture maize fields (P < 0.05). However, during the non-mulching period, the activity density, species richness, and Shannon-Wiener index of mesofauna in monoculture maize fields were significantly higher than in intercropping fields; (2) During the green manure mulching period, the activity density of spiders, predatory insects, herbivorous insects, ants, and springtails in maize and green manure intercropping fields were significantly higher than in monoculture maize fields; (3) During the green manure mulching period, the ratios of spiders to herbivorous insects (S/H), and spiders to other feeding types (S/O) was significantly higher in maize and green manure intercropping fields than in monoculture maize fields. In summary, intercropping maize with green manure significantly enhances soil fauna diversity during the mulching period, particularly enhancing predatory groups and their pest control functions, thus supporting the sustainable development of ecological agriculture in desert regions.

Understanding the dynamics of soil organic carbon (SOC) in the topsoil, the most sensitive part of soil profile to climate change, under future climate trajectories is vital for achieving carbon neutrality in China. However, large uncertainties and controversies exist in Earth System Model (ESM) simulations. We used a data-driven model to assess the responses of SOC to future climate change and quantified the critical biomass carbon input (i.e., net primary production, NPP) to preserve the current SOC level. Our results suggest that future warming alone may reduce the national topsoil organic carbon stock by 605.3 Tg C (1.72 %) by the end of the 21st century under the representative concentration pathway 8.5 (RCP8.5). However, the projected increase in precipitation cannot offset the negative impact of warming under all climate trajectories. We estimate that 18.5 %, 38.0 %, and 46.5 % of additional NPP are required in the 2030s, 2060s, and 2090s to offset the national SOC loss under RCP8.5, respectively. Further simulations driven by the NPP projections of ESMs suggest that the increasing NPP can confine warming-induced SOC loss within a small range and even slightly increase SOC in the 2090s under RCP4.5 and 8.5. Nevertheless, SOC dynamics show large spatial discrepancy, and regions with high SOC levels, especially Northeast and Southwest of China, have a high potential of losing carbon and deserve more attention. This work extends our knowledge about the future dynamics of topsoil organic carbon in China and can be a reference for current ESMs to produce more robust regional predictions.

Our previous researches showed that reed silicon (Si) accumulation positively responded to the groundwater depth (GD) changes, which was likely closely related to the involvement of Si in the nitrogen (N) metabolism. This study investigated the response relationship of reed Si and N accumulation with GD changes, the characteristics of photosynthetic parameters, and the indicators related to N metabolism, and explored the correlation between reed Si accumulation and indexes related to N metabolism under the changes of GD. The characteristics of photosynthetic parameters (PPs), Si, N accumulation and the indicators related to N metabolism were studied through field sampling analysis. Results indicated that reed Si and N accumulation positively responded to GD changes, the correlation of reed Si accumulation with N accumulation was significant positive, and reed accumulated Si and N as physiological regulators and maintained relative stability of Si: N ratio (0.37–1.57) to cope with the changes of GD. The PPs, and the indicators related to N metabolism of reed were significantly affected by GD changes, and the correlation of these indicators ( key enzymes in N metabolism, chlorophyll and N-containing organic solutes, etc.) with reed Si accumulation and water use efficiency (WUE) were significant positive, indicating that reed Si accumulation indirectly regulated the N metabolism by improving WUE to alleviate water stress under the changes of GD. These results indicate that Si and N accumulation play crucial roles in the drought resistance of reed, and the coupling effect of reed Si and N can provide theoretical reference for exploring effective technical measures for damaged ecosystems in desert oasis areas.

Hydrological niche segregation (HNS) is widely recognized as a key factor in species coexistence, but experimental evidence on water resource allocation among coexisting shrubs in desert ecosystems remains limited. We investigated the dynamics of hydrological niche segregation between two dominant desert shrubs (Nitraria sphaerocarpa and Reaumuria songarica) by analyzing stable isotope compositions (delta 2H, delta 18O) and soil water availability. The results showed that coexisting species exhibit distinct and flexible water use strategies. N. sphaerocarpa primarily utilizes shallow soil moisture during average precipitation periods but shifts to deeper water sources under arid conditions, with its distribution range spatially overlapping with that of R. songarica. Both coexisting species responded only to larger precipitation pulses, but N. sphaerocarpa exhibited higher uptake intensity and longer reliance duration on shallow water sources post-precipitation. As interannual precipitation decreases, the niche overlap between coexisting species significantly increases, while the niche width of R. songarica expands by 1.11 % and that of N. sphaerocarpa contracts by 3.24 %. These results highlight HNS as a dynamic mechanism that promotes coexistence through flexible resource partitioning. Under climate change scenarios, the plasticity of HNS is crucial for maintaining biodiversity in arid regions.

In desert regions, water availability for plants is extremely limited, making certain dominant species highly dependent on relatively abundant groundwater. To investigate the water distribution and relationships among coexisting xerophytic shrubs in arid habitats, we analyze the water consumption patterns of various species through stable isotope analysis (delta 18O and delta 2H). This analysis examines various water sources within the ecosystem, including soil water, rainfall, and groundwater, collected from six drought-tolerant shrub species. Our investigation revealed that evaporation in the upper layer of soil, which has low moisture content, occurs while deeper soil water, primarily recharged by groundwater, remains relatively abundant. Additionally, insufficient rainfall complicates the full recovery from prolonged soil water deficits. The vertical differentiation of soil moisture leads to varying water usage patterns among plants along the soil water gradient. The small shrubs, such as Reaumuria soongorica and A. sphaerocephala, obtained roughly 50 % of their water from shallow and mid soil layers, about 25 % from deep soil layers and about 25 % from groundwater, showing variable water source preferences according to soil water availability. As for large shrubs like Haloxylon ammodendron, Caragana microphylla, and Calligonum mongolicum, over 60 % of water was taken up from groundwater to meet the canopy water usage. Consequently, the differing water use patterns of coexisting plants stem from the vertical spatial variation of soil moisture, which allows for differentiated utilization of water resources and is essential for species coexistence in desert regions.

Background and aims Topography-induced changes in soil properties significantly influence vegetation distribution in desert ecosystems. While gravel deserts are generally flat, short gentle slopes are common. However, the effects of these slopes on soil properties and vegetation distribution under arid conditions remain unclear. Methods Utilizing field surveys and UAV technology, this study investigated the effects of short gentle slopes positions and depths on soil properties and vegetation distribution in the Linze gravel desert, Northwest China. ResultsSoil properties varied with both slope position and depth, even on slope less than 2 degrees. The 0-10 cm soil laye r showed greater variability than the 10-20 cm layer. At the 0-10 cm layer, the lower slope position had significantly higher saturated hydraulic conductivity (Ks) but lower silt, gravel content, and soil water repellency compared to the upper and middle positions (P < 0.05). The mean Ks across all slope positions was relatively low, averaging only 0.39 mm min-1. Considering gravel content significantly improved Ks prediction accuracy (P < 0.05). Variations in surface Ks were key to vegetation distribution. Vegetation distribution exhibited a significant downslope orientation pattern, with lower slopes having 2.2 to 3.7 times more coverage than middle and upper slopes (P < 0.001). Conclusions Limited infiltration capacity in gravel deserts led to the redistribution of precipitation across slope positions, even on short gentle slopes, resulting in distinct variation patterns. These findings suggest that lower slope positions are more favorable for native vegetation restoration, offering insights for managing gravel desert ecosystems.

Transforming arid and semi-arid deserts into farmlands significantly alters soil moisture and fertility, affecting the trophic structure and functionality of soil fauna. Diversity and function of soil macrofaunal community can accurately reflect changes in soil quality and health during the succession of oasis farmlands. In this study, the assemblage of soil macrofauna and soil environmental factors in cultivated and abandoned croplands in the Zhangye Oasis of Gansu Province, were investigated using a hand-sorting method, and we analyzed the relationship between the trophic structure of soil macrofauna and the soil environment. Our results showed that: 1) Farmland cultivation increased the soil water content, soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP), while reducing pH. 2) The density, taxon richness, and Shannon-Wiener index of soil macrofauna in cultivated croplands were higher than in abandoned croplands, increasing with cultivation duration. The density of soil macrofauna in 100-year-old farmlands was 2.5, 1.5 and 1.4 times of that in 10-year-old, 30year-old and 50-year-old farmlands; 3) the density and taxon richness of predatory, phytophagous, and other feeding types of soil macrofauna in cultivated croplands were higher than those of abandoned croplands. The observed increases in density and taxon richness are likely due to the improved soil conditions resulting from cultivation practices. The density-based ratio of predatory to phytophagous and other feeding types of soil macrofauna initially increases then decreases, inversely related to cultivation age. 4) changes in soil environment had little effect on the predatory soil macrofaunal community, and the explained variance by SOC, TP, and pH indicates the significant influence of these soil properties on the composition of the phytophagous soil macrofaunal community. SOC, TP, and pH explained 7.3 % of the variation in phytophagous soil macrofaunal community, while TN, TP, and pH explained 15.4 % of the variation in other feeding types of soil macrofauna. In conclusion, our findings highlight the positive impact of oasis farmland cultivation on soil quality and the enhancement of soil macrofauna diversity, which in turn could contribute to the resilience and productivity of these agricultural ecosystems.