Understanding the drivers of gross primary production (GPP) is essential for assessing vegetation productivity dynamics under climate change, particularly across regions with strong climatic heterogeneity. China spans diverse climate zones and ecosystems, yet the relative importance of climatic, environmental, and anthropogenic factors regulating GPP has remained poorly resolved. In this study, we investigated the spatiotemporal patterns of GPP across China from 2001 to 2020 and quantified the contributions of multiple driving factors across different climate zones. We combined ridge regression with an interpretable machine learning framework based on Extreme Gradient Boosting (XGBoost) and SHapley Additive exPlanations (SHAP) to disentangle the long-term linear controls on and short-term nonlinear responses driving GPP. Ridge regression was employed to address multicollinearity among predictors and to quantify their interannual contributions, while SHAP analysis was used to quantify feature contributions in nonlinear model predictions. Our results indicated that leaf area index (LAI) and human footprint dominated the long-term variability of GPP in most climate zones, whereas temperature and solar radiation exerted stronger influences on instantaneous GPP responses. The relative importance of drivers varied markedly among climate zones, reflecting region-specific climatic constraints and vegetation physiological characteristics. In addition, the contribution of atmospheric CO₂ to GPP variability was notably limited in the alpine climate zone and showed a declining fertilization effect nationally, suggesting increasing constraints imposed by water availability and nutrient limitations. By integrating linear attribution and nonlinear interpretability, this study provides a comprehensive assessment of the controls on GPP dynamics across China and highlights the importance of accounting for climatic heterogeneity and temporal scales when evaluating vegetation productivity responses to environmental change.

The Shaanxi-Gansu-Ningxia (SGN) border region, as a typical transitional zone between the East Asian monsoon and the westerlies, features a fragile ecological environment. In this study, the spatiotemporal evolution and multiscale driving mechanisms of surface winds in this ecologically fragile transition zone were investigated by integrating trend analysis, empirical orthogonal function (EOF) decomposition, and geographic detector method. The results indicated that from 1980 to 2022, the annual mean surface wind speeds in the SGN border region significantly increased, with a linear growth rate of 0.003 m/(s•a). However, the anomaly series revealed a clear interdecadal transition: surface wind speed anomalies were predominantly negative from 1980 to 1999 and shifted to persistently positive and increasing anomalies after 2000. Consistent strengthening was observed in summer, autumn, and winter, with the most pronounced increase occurring in autumn. The spatial distribution generally followed a pattern of higher values in the northwest and lower values in the southeast. Spring presented the strongest surface wind speeds and the most extensive areas with high values. EOF analysis revealed two dominant spatial modes: the first mode (variance contribution>73.40%) reflected regionally consistent changes, and its temporal coefficients increased continuously, corresponding to the overall strengthening trend of surface wind speed; and the second mode exhibited an east-west dipole oscillation pattern, dominated by interannual fluctuations. The geographic detector results revealed that fractional vegetation cover (FVC), temperature, and topographic elevation were key factors influencing the spatial differentiation of surface wind speeds, with all the factors exhibiting enhanced interactive effects—especially the synergistic effect between vegetation cover and temperature. Background circulation analysis indicated that enhanced westerlies and decreased geopotential height in the mid- to upper-troposphere provided favourable dynamic conditions for increased surface wind speeds. This study advances the understanding of surface wind speed changes in climate transition zones, providing a scientific basis for regional wind energy planning, ecological protection, and wind erosion control.

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.

Accelerated global climate change and intensified human activities profoundly alter landscape patterns and ecosystem services (ESs), making the quantitative evaluation of their dynamic interactions essential for advancing regional sustainable development. This study focused on Qilian Mountain National Park and employed FRAGSTATS 4.2 to analyze the landscape pattern evolution from 2000 to 2020. The Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model was used to assess five key ESs: water yield (WY), carbon storage (CS), water quality purification (ND), soil retention (SR), and habitat quality (HQ). Ecosystem service bundles (ESBs) were identified using a self-organizing map (SOM) approach, and nonlinear relationships between landscape pattern indices and ESs were examined using the Boosted Regression Tree (BRT) model combined with spearman correlation and clustered heatmap analyses. The results indicated that the landscape pattern of Qilian Mountain National Park exhibits a clear east to west gradient. The spatiotemporal dynamics of ESs showed divergent trends, with CS and ND consistently improving, whereas WY exhibited pronounced nonlinear fluctuations. ESBs were classified into four types: ESB I (ecosystem transition bundle), ESB II (ecosystem regulation and protection bundle), ESB III (ecosystem degradation and protection bundle), and ESB IV (ecosystem restoration bundle), reflecting a shift from single function dominance toward multifunctional synergies. A nonlinear coupling relationship existed between landscape pattern indices and total ecosystem services (TES), characterized by a notable decline in TES and continued degradation of ES performance and stability. Together, this study provides a robust scientific foundation for developing differentiated zoning management strategies. The findings deliver valuable scientific insights for the management of ESs in the Qilian Mountain National Park and similar mountain ecosystems, while offering a reference for promoting sustainable development in fragile ecological regions worldwide.

Blowouts are important aeolian landforms in the Horqin Sandy Land, China and their development and evolution are crucial for understanding regional environmental changes. However, relevant studies remain scarce, and those that exist have primarily focused on dune dynamics rather than blowout-specific processes. Based on multi-temporal high-resolution satellite remote sensing images and field measurement data from 2017 to 2024, this study analyzed the distribution pattern, dynamic evolution, developmental models, and driving factors of blowouts in the Horqin Sandy Land. We used the space-for-time substitution method to classify developmental stages according to morphological parameters and employed spatial interpolation (kriging) to construct high-precision digital elevation models (DEMs) from Real-Time Kinematic-Global Positioning System (RTK-GPS) survey data. The results showed that the main types of blowouts in the Horqin Sandy Land are trough, saucer, and composite blowouts, located between 119°19′26′′-119°26′15′′E and 43°05′20′′-43°12′13′′N, mostly distributed in linear or beaded patterns that are closely related to regional wind regimes and gentle terrain. From 2017 to 2024, the areas of saucer, trough, and composite blowouts in the study area increased by 49.20%, 34.88%, and 30.64%, respectively. The evolutionary process of blowouts can be divided into three developmental stages: initial stage (IS), mature stage (MS), and stable stage (SS). The IS can be further subdivided into three subtypes: IS-I (morphological initiation), IS-II (morphological expansion), and IS-III (morphological stabilization). As blowouts evolved from the IS to the SS, their morphology continuously enlarged. The growth rate of the length-to-width ratio gradually decreased, whereas the growth rates of both area and volume showed an increasing trend. These changes were driven by airflow erosion and modulated by vegetation cover and soil texture. Notably, blowouts in the SS exhibited the most significant changes during the study period, with their area and volume changing by 684.74 m² and 2284.39 m³, respectively, while their length-to-width ratio and height slightly decreased. Erosion-deposition patterns differed among blowout components: in contrast to the erosion-dominated sidewalls and upwind entrance, the erosion pit area was predominantly characterized by deposition, resulting from airflow deceleration and additional sediment input from livestock trampling and sidewall collapse. This study provides a scientific basis for establishing a developmental model of blowouts and promoting the sustainable development of the Horqin Sandy Land.

Slopes in arid and semi-arid areas typically have low vegetation cover and are highly susceptible to extreme precipitation-induced hazards such as landslides and debris flows. Although ecological slope protection can regulate soil water dynamics through canopy interception, transpiration, and root water uptake, the specific moisture-regulation roles of different vegetation types remain unclear. In this study, Festuca arundinacea Schreb. (tall fescue) and Medicago sativa L. (alfalfa) were selected as representative slope-protecting species. Long-term field monitoring combined with HYDRUS 2D/3D numerical simulations was employed to analyze soil moisture dynamics under precipitation events. The results indicated that the dense canopy of tall fescue effectively delayd surface runoff and enhanced infiltration, increasing shallow soil moisture to 33.400%; however, its strong transpiration caused rapid post-precipitation depletion, with moisture decreasing by approximately 1.500%. In contrast, the sparse canopy of alfalfa leads to lower surface soil moisture (32.800%), while its deep taproot system facilitated downward water migration, gradually increasing deep soil moisture and maintaining post-precipitation stability. Numerical simulations further revealed distinct interspecific differences in precipitation response, soil moisture evolution, and vertical water redistribution. Shallow-rooted tall fescue exhibited rapid, short-term responses in the shallow layer, whereas deep-rooted alfalfa demonstrated deep-layer water storage and long-term stability. The findings demonstrate that vegetation type exerts distinct regulatory effects on overall slope moisture dynamics, offering a scientific foundation for optimizing slope-protection plant selection and enhancing hydrological regulation under extreme climatic conditions in arid and semi-arid areas.

In arid regions, saline subgrades are highly susceptible to deterioration caused by evaporation-driven water-salt migration, which can induce salt accumulation, cracking, and long-term loss of stability. To investigate the role of sand replacement layers in regulating thermo-hydro-saline (THS) migration under evaporation, we conducted indoor soil-column experiments in combination with microstructural observations. The effects of sand type (coarse, medium, and fine sand) and replacement ratio (0.00%, 20.00%, 35.00%, and 50.00%) were systematically examined under simulated high-temperature and strong-evaporation conditions typical of northwestern China, with continuous monitoring of temperature, relative humidity (RH), and electrical conductivity (EC). The results show that sand replacement effectively inhibited capillary rise, reduced surface salt accumulation, and alleviated shrinkage cracking. Among the tested sand types, coarse sand exhibited the strongest inhibitory effect on upward water-salt migration, whereas fine sand showed the weakest effect because its smaller pores and stronger capillary continuity facilitated upward water-salt migration. Under the medium sand condition, increasing the replacement ratio was associated with stronger suppression of surface salt accumulation, with the 50.00% replacement ratio showing the strongest effect. However, the influence of replacement ratio was not monotonic across all response indicators. A replacement ratio of approximately 35.00% maintained relatively continuous pathways for heat and moisture transfer, whereas higher replacement ratios produced a looser soil skeleton and weaker capillary continuity. Microstructural observations further revealed that salt crystals mainly accumulated near the evaporation front and the lower replenishment zone, while coarse sand tended to form larger pores and reduce matric suction, thereby disrupting upward migration pathways. These findings provide a theoretical basis and technical support for optimizing saline subgrade design and mitigating salt-related damage in arid regions.

Soil salinization is a critical factor influencing nitrogen dynamics and crop productivity in arid irrigated areas. In salt-affected areas, a significant mismatch exists between high nitrogen fertilizer input and low nitrogen use efficiency (NUE). This research quantitatively evaluates the influence of soil salinity on the fate and distribution pathways of nitrogen, as well as the total nitrogen balance and NUE in maize (Zea mays L.) fields. A two-year field experiment was conducted in the Hetao Irrigation District, located in the upper reaches of the Yellow River basin, China, to monitor nitrogen loss pathways (N₂O emissions, NH₃ volatilization, and nitrogen leaching) and crop physiological responses under three salinity gradients (non-saline, slightly saline, and moderately saline). The results demonstrated that salinity stress significantly intensified the loss of reactive nitrogen, increasing the cumulative N₂O emissions by 55.61%-283.05% and NH₃ volatilization by up to 80.61%. Notably, nitrate leaching increased by 97.44%-248.93% in slightly saline fields, posing a higher environmental risk than in moderately saline fields. The accelerated loss of reactive nitrogen, coupled with suppressed maize growth and grain yield, led to a substantial decline in the partial factor productivity of nitrogen fertilizer. Therefore, tailored water and fertilizer practices (e.g., precision irrigation, split fertilization or urease inhibitor application) are required in a salt-affected field to reduce reactive nitrogen losses and enhance NUE.

Desert steppe ecosystems are highly sensitive to variations in water and nitrogen (N) levels. Soil microarthropods serve as crucial indicators of belowground ecological processes, yet their responses to long-term water-N interactions remain unclear. This study investigated the combined effects of long-term N deposition and rainfall variation on the microarthropod community in the desert steppe soil, as well as their potential driving mechanisms. Utilizing a field control experimental platform for global change in the desert steppe of Inner Mongolia Autonomous Region, China, researchers had established a multigradient two-factor (water-N) experiment since 2015. The experiment employed a split-plot design with three water levels (natural rainfall (NR), 30.00% rainfall enhancement (RE), and 30.00% rainfall reduction (RR)) and four N addition levels (0 (N0), 30 (N30), 50 (N50), and 100 (N100) kg N/(hm²•a)), resulting in 12 treatment combinations. After the experimental treatments had been conducted for 5 a and treatment effects had reached a long-term steady state, we collected the soil samples to analyze the variations of soil microarthropod communities. The results revealed that at varying water conditions, N addition increased the abundance, number of taxa, and diversity of soil microarthropods. In the RE treatment, the total abundance and total number of taxa of soil microarthropods were significantly greater than those in the NR and RR treatments. Water-N interactions had a significant effect on soil microarthropod community structure, with the N30 treatment coupled with water variation having the strongest effect. Moreover, the influence of N addition on soil microarthropod communities depended on water changes; both the RR and RE treatments amplified the effect of N addition, with the RR treatment resulting in the greatest amplification. N deposition and changes in rainfall shape the soil microarthropod community by altering key environmental factors. N addition and water variation positively affect the abundance of soil microarthropods by increasing the ammonium nitrogen (NH₄⁺-N) content, litter fall (LF), and soil moisture (SM) content. The interaction between water and N primarily promotes soil microarthropod abundance by reducing the NH₄⁺-N content and increasing the biomass of perennial grass. In summary, this study not only reveals the key pathways through which water and N drive changes in the soil microarthropod community in desert steppes but also provides a scientific basis for understanding soil biodiversity maintenance and ecosystem management in arid regions under global change.