The South Aral Seabed is an extreme dryland ecosystem undergoing rapid transformation yet remains misrepresented or absent in global land cover datasets. Conventional vegetation indices, specifically the Normalized Difference Vegetation Index (NDVI), perform poorly in such environments due to their limited ability to distinguish sparse vegetation from highly reflective saline and sandy soils. This study evaluated the effectiveness of the Modified Soil Adjusted Vegetation Index (MSAVI) for improving land cover classification in the South Aral Seabed and conducted a decadal analysis of land cover change between 2013 and 2023 using Landsat 8 imagery (30 m resolution). A spectral index-based classification framework was developed, combining MSAVI with the Normalized Difference Water Index (NDWI) and Salinity Index 1 (SI1) to reduce spectral confusion between vegetation, saline soils, and surface water. The MSAVI-based classification achieved an overall accuracy of 77.96% (Kappa coefficient=0.71), supported by 313 field-collected validation points from 2023. While the multi-index approach enabled finer discrimination of ecologically important classes, particularly separating salt pans from solonchak soils, it resulted in a lower overall accuracy (73.80%), highlighting a trade-off between class separability and classification performance. Land cover change analysis revealed a highly dynamic landscape, with 52.96% of the study area transitioning between classes over the decade. Transformed areas (16,893 km²) exceeded stable zones (15,004 km²), driven primarily by rapid desiccation and salinization. Solonchak soils increased at an annual rate of 5.58%, while surface water bodies declined by 4.83% per year. Concurrently, sparse or distressed vegetation increased by 1.43% annually, reflecting ongoing afforestation efforts. This study provides the first MSAVI-based and medium-resolution land cover baseline for the South Aral Seabed and demonstrates that soil-adjusted vegetation indices are essential for reliable dryland classification where conventional indices fail. The proposed spectral index framework offers a replicable methodology applicable to other global drylands facing similar land degradation and restoration challenges.

Fire is a fundamental ecological driver shaping natural vegetation patterns. In the semi-arid southern Espinal-Monte ecotone of Argentina, the spatiotemporal patterns of fire occurrence related to and modulated by climatic gradients and antecedent conditions are not well researched. This study examined fire occurrence in the semi-arid southern Espinal-Monte ecotone (southeastern La Pampa, northeastern Río Negro, and southwestern Buenos Aires with an area of 68×10³ km²) of Argentina, a key environmental transition zone with pronounced climatic and vegetation gradients. The objective was to identify the spatiotemporal patterns of fire occurrence and their relationship with climatic variables. Thermal anomaly (TA) data from the MODIS (Moderate Resolution Imaging Spectrometer; MOD14) sensor (November 2000-March 2020) with confidence levels >65.0% were analyzed. Climatic variables (rainfall isohyets and aridity indices) were obtained from the WorldClim datasets, and annual meteorological conditions (rainfall and potential evapotranspiration) were calculated using the climatic research unit (CRU) database. Monthly data and moving averages of rainfall and aridity indices from distinct periods (two and three years preceding fire events) were integrated. Spatial analysis was conducted using kernel density estimation on a 10 km×10 km grid to correlate TA with climatic gradients, while linear regression examined relationships between summer TA and meteorological variables over different periods. Results showed that the highest fire occurrence was recorded in summer, with peaks in December and January. Spatially, 55.0% of TA occurred in areas with annual rainfall of 300-400 mm, and 64.5% in areas with an aridity index of 0.3-0.4, forming an arc-like distribution in the center of the ecotone. The highest TA densities were observed in southeastern La Pampa and northeastern Río Negro, decreasing toward southwestern Buenos Aires. Significant correlations (R²>0.700) were found among TA accumulation, aridity index values, and cumulative rainfall from previous two and three years, at both vegetation unit and provincial levels. Summer was the critical season for fire occurrence, with spatial distribution primarily determined by the interaction between climatic conditions and woody biomass availability. The lower fire incidence in southwestern Buenos Aires was linked to sparse woody vegetation and agricultural expansion, which reduced fuel load. These findings reinforce that fuel availability, modulated by climatic conditions from previous years, is a key limiting factor for fire dynamics in this area, and that human activities such as agriculture and grazing alter fire regimes by affecting fuel structure and continuity.

Glacial meltwater constitutes a vital component of the water supply in arid and semi-arid areas. However, the influence of glacial melting on runoff and evapotranspiration under global warming remains insufficiently understood. Previous studies coupling the Soil and Water Assessment Tool (SWAT) model with glacier modules often failed to consider the spatial heterogeneity of temperature during glacial melting, potentially leading to biased estimates of meltwater volume. In this study, we developed a glacier-coupled SWAT (SWAT-glacier) model considering the digital elevation model (DEM) based temperature-driven glacial melt processes to elucidate the impact of glacial melting on hydrological processes across four river basins (Dongda, Xiying, Jinta, and Zamu) of the upper Shiyang River Basin (SYRB) in northwestern China from 1986 to 2021. Compared with the standard SWAT model, the proposed SWAT-glacier model significantly improved the simulation accuracy for both runoff and evapotranspiration. Specifically, in comparison with the standard SWAT model, the Nash-Sutcliffe efficiency of the SWAT-glacier model showed a relative improvement of approximately 0.42%-9.16% and 1.50%-10.15% for runoff and evapotranspiration, respectively, in the four river basins during the validation period. Annual glacial runoff occurred predominantly from May to October, whereas glacial melt-induced evapotranspiration peaked between June and August. From 1986 to 2021, the average contributions of glacial melt to runoff were 6.97% for Dongda, 3.06% for Xiying, 2.70% for Jinta, and 0.67% for Zamu, whereas its contributions to evapotranspiration were 9.06%, 5.14%, 3.21%, and 1.59%, respectively. This study presents a SWAT-glacier modeling framework that enhances the simulation of hydrological processes in cold regions. The proposed methodology can be extended to other glacierized basins to provide valuable insights into water resource management under climate change.

In the northern Tarim River Basin, the Weigan River Basin is a critical endorheic system characterized by extreme aridity, where drought poses a major natural hazard to agricultural production and ecological stability. This study assessed the future evolution of drought under climate change by employing the standardized moisture anomaly index (SZI) on the basis of multi-model the Coupled Model Intercomparison Project Phase 6 (CMIP6) simulations under historical conditions (1970-2014) and future scenarios (shared socioeconomic pathway (SSP)1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5 for 2015-2100). The results show that precipitation-evapotranspiration anomalies are projected to first decline but then increase over time, with increased fluctuations and uncertainty under high-emission scenarios (SSP5-8.5). These trends indicate intensifying drought risks and reveal a strong influence of emission pathways on regional water cycling. Temporal analysis of SZI indicates a transition from wetting to drying under low- and medium-emission pathways (SSP1-2.6 and SSP2-4.5), whereas high-emission scenarios are characterized by persistent drying and increased variability. The significant lower-tail dependence (0.271) observed under SSP2-4.5 and SSP5-8.5 suggests that extreme droughts may be subject to nonlinear co-amplification across scenarios. The frequency of moderate and more severe drought events is expected to increase substantially, especially under SSP5-8.5, where drought occurrence is predicted to extend into spring and autumn and become more evenly distributed throughout the year. Spatially, drought duration shows significant positive autocorrelation across all scenarios, with hot spots consistently concentrated in the southern and southeastern regions of the basin. Random forest analysis, interpreted as association-based pattern attribution, indicates that meteorological variables (precipitation and potential evapotranspiration (PET)) make the greatest contributions to the hot spot pattern, followed by topography and soil moisture. Among land use categories, farmland generally shows higher drought sensitivity than other land use types, as reflected by its relative contribution patterns across scenarios. The spatial pattern of drought is statistically structured by climatic forcing, surface conditions, and soil moisture status, reflecting their coupled associations with hot spot occurrence. In addition, a drought spatial uncertainty index was constructed from multi-scenario hot spot maps, revealing spatially heterogeneous structural variability throughout the basin. Correlation analysis further highlights strong internal couplings among environmental variables (e.g., elevation-linked hydroclimatic gradients and grassland-bare soil contrasts). These findings offer a scientific basis for developing region-specific drought monitoring and adaptation strategies under future climate change conditions.

Cyperus esculentus (C. esculentus), a desert-adapted plant species with both ecological and economic value, has been widely cultivated in northern China's sandy regions. However, limited studies have investigated the performance of composite shelterbelts that integrate C. esculentus. This study systematically evaluated five shelterbelt models—Populus euphratica (P. euphratica), P. euphratica-C. esculentus composite, P. euphratica-nylon net-C. esculentus composite, Tamarix chinensis (T. chinensis), and T. chinensis-C. esculentus composite—using wind tunnel experiments and field observations. Sediment flux was measured at a normalized downwind distance (x/h) of 5, where x refers to the distance from the front edge (upwind side) of the shelterbelt for upwind measurements, and the distance from the rear edge (downwind side) for downwind measurements, and h represents the canopy height. Wind velocity was measured at x/h of -2, -1, 1, 2, 3, 5, and 7, and sand flux was measured at x/h=5, under initial wind velocities of 8.0 and 12.0 m/s. The results indicated that the P. euphratica-nylon net-C. esculentus composite was the most effective in reducing wind velocity, followed by the P. euphratica-C. esculentus composite. In contrast, the P. euphratica and T. chinensis exhibited relatively weaker wind reduction capabilities. Regarding sand flux, under moderate wind velocity (8.0 m/s), both the P. euphratica-C. esculentus composite and P. euphratica-nylon net-C. esculentus composite demonstrated the lowest sand flux values. However, under high wind velocity (12.0 m/s), the P. euphratica-nylon net-C. esculentus composite significantly outperformed the other shelterbelt models in sand retention, highlighting its superior windbreak and sand fixation efficacy. Field observations further validated the windbreak and sand fixation effects of C. esculentus. Comparisons between the bare sand plot and C. esculentus plot within protective forests demonstrated that planting C. esculentus can provide substantial ecological benefits in windbreak and sand-fixation. These findings, reinforced by field observations, strengthen the wind tunnel experiment results and highlight the critical role of C. esculentus in enhancing the performance of composite shelterbelts for desert ecological restoration.

The banks in the middle and lower reaches of the Tarim River in China are weak in erosion resistance and prone to collapse. Vegetation, as a natural reinforcement material, can effectively improve slope stability and curb soil erosion. In March and July 2023, a field survey was conducted on the types and distribution characteristics of vegetation along both banks of a certain section in the lower reaches of the Tarim River. Taking COMSOL Multiphysics as the finite element numerical simulation platform, we investigated the variation law of bank slope stability in the middle and lower reaches of the Tarim River under different root morphologies, considering changes in transpiration time, rainfall, and water level under the action of hydro-mechanical reinforcement. The findings showed that vegetation transpiration has a significant effect on soil pore water pressure. Given the same transpiration rate, shorter root systems produced greater pore water pressure. For equal root lengths, the pore water pressures generated by roots in exponential and triangular morphologies were significantly greater than those generated by roots in uniformly distributed and parabolic morphologies. The water absorption capacity of the root system increased with transpiration rate. After 7 d of transpiration, the maximum safety factor of the bank slope reinforced by exponential roots was 1.568, which was a 9.88% improvement over that of the bare slope. After 24 h of rainfall, the effect of vegetation transpiration on soil pore water pressure weakened rapidly; the pore water pressure of the surface soil generated by transpiration from vegetation with different root morphologies was concentrated near -10.00 kPa. After rainfall, the displacement of the exponential root reinforced slope was minimized to 0.137 m. The effect of transpiration-induced changes in substrate suction on slope stability was negligible during the rainfall period. Compared with that of the bare slope, the displacements of bank slopes reinforced by root systems significantly increased. The maximum displacement occurred when the water level changed by 1.5 m/d; the displacement of the bare slope was 0.554 m, whereas the displacements of bank slopes reinforced by roots in different morphologies were 0.260-0.273 m. The impact of vegetation transpiration on the safety factor of riverbanks under sudden water level drops was relatively minor, but it can enhance the stability of riverbanks to a certain extent. Among these, riverbanks reinforced by roots in triangular and exponential morphologies exhibited superior stability compared with those reinforced by uniformly distributed or parabolic root systems. The findings offer a theoretical basis and practical guidance for designing vegetation slope protection in the middle and lower reaches of the Tarim River.

Arid and semi-arid ecosystems are prone to extensive fires due to specific climatic conditions, sparse vegetation cover, and high density of fine fuels. Understanding the flammability characteristics of land covers is essential for fire management and designing land restoration programs in arid and semi-arid ecosystems. This study provided a new approach to evaluate the flammability of shrublands and woodlands using flammability indices (FIs) including time to ignition (TI), duration of combustion (DC), and flame height (FH) of plant species and their relative frequencies in the Dalfard Basin of southeastern Iran. The results showed that there was a significant difference in FIs between land covers. Shrublands had higher flammability potential compared with woodlands. Plant moisture content had a negative relationship with TI (P<0.010) and no significant relationship with DC and FH (P>0.050). Artemisia spp., Astragalus gossypinus Fischer, Amygdalus scoparia Spach, and Cymbopogon jwarancusa (Jones) Schult. had the highest FI. Tree species such as Rhazya stricta Decne., and Pistacia atlantica Desf. showed greater resistance to fire. Using principal component analysis, the relationship between species and FIs was examined, and TI of wet fuel was the most important FI in relation to species. Structural equation model showed that life form (P<0.001) was the most important flammability driver. Precipitation (P<0.010) and legume species (P<0.010) were significantly related to the flammability in arid land. This study emphasizes the importance of managing high-risk species and using resistant species in vegetation restoration and shows that combining species FIs with their abundance is an effective tool for assessing fire risk and fuel management at the plant community scale.

Global grassland degradation necessitates the identification of sustainable grazing management strategies. In semi-arid regions, grazing exclusion (GE), cold-season grazing (CG), and free grazing (FG) represent common practices in grassland ecosystems, yet the long-term ecological consequences of these patterns on plant community structure and soil aggregate stability remain inadequately elucidated. In this study, we evaluated the effects of GE, CG, and FG on soil organic carbon, soil water content, soil bulk density, soil aggregates, and vegetation indicators in Xilamuren steppe, a semi-arid grassland in northern China through field sampling and laboratory analyses in 2024. Our findings revealed that, compared to CG and FG, GE significantly enhanced aboveground and belowground biomass, species diversity, and soil physical-chemical properties in the 0-30 cm layer. The dominant plant species in GE and CG sites were Stipa krylovii, Leymus chinensis, and Agropyron cristatum, whereas Stipa krylovii, Artemisia frigida, and Leymus chinensis were predominant in FG site. Different grazing patterns led to distinct soil aggregate distributions, with >2.00 and <0.25 mm aggregates exhibiting the highest content in different soil layers depending on the grazing patterns. All grazing management strategies significantly improved soil aggregate stability, with the overall stability following the order: GE>CG>FG. Furthermore, random forest modeling identified plant species diversity, plant growth traits, and grazing patterns as the primary determinants of soil aggregate stability. Collectively, these results offer valuable insights into the sustainable management and ecological restoration of semi-arid grasslands under different grazing pressures.

The escalating global demand for sustainable agriculture necessitates the development of effective biological alternatives to conventional chemical fertilizers, particularly those addressing phosphorus (P) use efficiency. This study focused on the isolation and detailed characterization of phosphate-solubilizing fungi from soil or compost to evaluate their impact and potential for use as biofertilizers. Fungal isolation was performed using serial dilution from various sources, followed by molecular and morphological characterization to identify promising strains. Four strains were ultimately selected and identified using morphological, biochemical, and molecular techniques: Aspergillus flavus (CM1), Penicillium crustosum (C3), Penicillium fellutanum (C4), and Metarhizium robertsii (J1). The most active strain was initially tested in liquid and solid media supplemented with synthetic P (Ca₃(PO₄)₂) and was evaluated by measuring fungal biomass and P titration. This strain demonstrated good growth and activity, supporting an optimal temperature of 25°C, a pH of 3, an ammonium concentration of 1.5 g/L, and a glucose addition of 25.0 g/L. The biofertilization potential of the selected strains was then comprehensively evaluated through controlled experiments, including the optimization of growing conditions, quanti fication of soluble P under hermetic storage in soil, and measurement of soil fungal populations to assess their impact. P transformation experiments conducted in hermetic jars showed that CM1 had the highest CO₂ release (approximately 7115.30 mg CO₂/100 g soil) and the highest soluble P levels at the final sampling time (78.85 mg/L), thus outperforming the other strains. Furthermore, in soil hermetic jars, CM1 (reaching up to 26×10⁴ CFU (colony forming units)/g soil) and C4 significantly enhanced soil microbial activity and P bioavailability. These results clearly highlight the potential of the selected fungal strains as biofertilizers to improve P availability and boost crop productivity in P-deficient soils.