Central Asia is characterized by an arid climate and widespread desert distribution, with its sustainable development severely constrained by dust events. An objective understanding of the spatiotemporal patterns and driving forces of dust weather is highly important in this area. Based on the meteorological observations from 2000 to 2020, we examined the spatiotemporal characteristics of dust weather in the five Central Asian countries (Kazakhstan, Uzbekistan, Kyrgyzstan, Turkmenistan, and Tajikistan) via Theil-Sen trend analysis and Geodetector modeling method, quantitatively revealing the influence of environmental factors, such as temperature, precipitation, and vegetation, on the frequency of dust weather. The results showed that: (1) dust weather in Central Asia was mainly distributed in a large ''dust belt'' extending from west to east from northern part of the Caspian lowland desert, and concentrated in basins, plains, and other low-altitude areas. Strong dust weather mainly occurred in northern areas of the Aral Sea and southern edge of Central Asia, with a maximum annual frequency of 21.9%; (2) strong dust weather in Central Asia has fluctuated and slightly decreased since 2001. The highest frequency (1.1%) occurred in spring (from March to June); (3) from 2000 to 2020, changes such as spot shifting and shrinking occurred in the four main source areas (north of the Aral Sea, Kyzylkum Desert, Karakum Desert, and Garabogazköl Bay region), where sandstorms occurred in Central Asia, and northern Caspian lowland desert became the most important low-emission dust source in Central Asia; and (4) the combined effect of soil moisture and air temperature has the most significant influence on dust weather in Central Asia. This study provides a theoretical basis for sand prevention and sand control in Central Asia. In the future, Central Asia should focus on the rational utilization of land and water resources, and implement human interventions such as vegetation restoration and optimization of irrigation methods to curb further desertification in this area.

Land use in arid and semi-arid regions has a substantial effect on climate, environment, and biodiversity, thereby projecting the spatiotemporal changes in land use and the subsequent effects. This study employed the locally calibrated Future Land Use Simulation (FLUS) model, which coupled system dynamics with cellular automata and integrated an artificial neural network algorithm and a roulette wheel selection mechanism. We projected future land use (2020-2100) dynamics of Lanzhou, a typical river valley city in Northwest China, under three different Shared Socioeconomic Pathway (SSP) scenarios (SSP1-2.6, SSP2-4.5, and SSP5-8.5). The simulation results were validated and subsequently reclassified using the International Geosphere Biosphere Programme (IGBP) system to produce a dataset suitable for driving climatic and environmental models. Under the SSP1-2.6 scenario, urban and built-up land expanded consistently, whereas irrigated cropland and pasture as well as grassland contracted continuously. Conversely, the SSP5-8.5 scenario was characterized by a contraction of urban and built-up land, and relative stability of irrigated cropland and pasture as well as grassland. The SSP2-4.5 scenario presented a more complex trade-off, where urban and built-up land and grassland increased first and then decreased, whereas irrigated cropland and pasture followed an opposite trajectory. A significant inverse relationship between urban and built-up land and irrigated cropland and pasture was observed under all scenarios, underscoring the fundamental spatial competition that prevailed in this land-constrained valley city. Furthermore, the negative correlation of grassland with urban and built-up land, coupled with the positive correlation of grassland with irrigated cropland and pasture under both the SSP1-2.6 and SSP5-8.5 scenarios, indicated an evolution from broad confrontation to intricate internal trade-offs within the urban-agricultural-ecological system. This study underscored the critical influence of regional topographic and hydrological constraints on land-use evolution in arid regions, providing guidance for water resource management and ecosystem protection in Lanzhou, with applications for sustainable land-use planning in other arid and semi-arid river valley cities.

Vegetation in terrestrial ecosystems as a carbon sink is a crucial factor in mitigating global warming and reaching carbon neutrality targets, although the drivers of net ecosystem productivity (NEP) under combined human and environmental pressures remain poorly understood. In this study, we analyzed the spatiotemporal evolution of NEP in the Horqin Sandy Land, China from 2000 to 2020, and observed the variation in NEP across different land use types. We further identified and quantified the effects of human activities, topographical features, climatic conditions, and soil properties on NEP through the application of structural equation modeling (SEM) and boosted regression trees (BRT). The results showed that the multi-year average NEP ranged from -137.79 to 461.96 g C/m² in the Horqin Sandy Land, with 88.21% of the area showing a significant increasing trend. Among different land use types, forestland exhibited the highest NEP values, followed by cropland, grassland, impervious land, and unused land. The NEP in carbon sink areas was primarily regulated by potential evapotranspiration (negatively correlated) and precipitation (positively correlated). Slope was identified as the most significant positive determinant in carbon source areas. Forestland exhibited climate-topography interactions driving NEP, whereas cropland and grassland relied on temperature; unused land and impervious land were susceptible to land use/cover change and human footprint. This study has significant implications for maintaining the carbon sink function and promoting ecological engineering programs that aim to enhance the capacity of terrestrial carbon sinks in the semi-arid agro-pastoral ecotone.

Arid mountain ecosystems are highly sensitive to hydrothermal stress and land use intensification, yet where net primary productivity (NPP) degradation is likely to persist and what drives it remain unclear in the Tianshan Mountains of Northwest China. We integrated multi-source remote sensing with the Carnegie-Ames-Stanford Approach (CASA) model to estimate NPP during 2000-2020, assessed trend persistence using the Hurst exponent, and identified key drivers and nonlinear thresholds with Extreme Gradient Boosting (XGBoost) and SHapley Additive exPlanations (SHAP). Total NPP averaged 55.74 Tg C/a and ranged from 48.07 to 65.91 Tg C/a from 2000 to 2020, while regional mean NPP rose from 138.97 to 160.69 g C/(m²•a). Land use transfer analysis showed that grassland expanded mainly at the expense of unutilized land and that cropland increased overall. Although NPP increased across 64.11% of the region during 2000-2020, persistence analysis suggested that 53.93% of the Tianshan Mountains was prone to continued NPP decline, including 36.41% with significant projected decline and 17.52% with weak projected decline; these areas formed degradation hotspots concentrated in the central and northern Tianshan Mountains. In contrast, potential improvement was limited (strong persistent improvement: 4.97%; strong anti-persistent improvement: 0.36%). Driver attribution indicated that land use dominated NPP variability (mean absolute SHAP value=29.54%), followed by precipitation (16.03%) and temperature (11.05%). SHAP dependence analyses showed that precipitation effects stabilized at 300.00-400.00 mm, and temperature exhibited an inverted U-shaped response with a peak near 0.00°C. These findings indicated that persistent degradation risk arose from hydrothermal constraints interacting with land use conversion, highlighting the need for threshold-informed, spatially targeted management to sustain carbon sequestration in arid mountain ecosystems.

The connection between climatic factors and grazing is essential for maintaining ecosystem function and vegetation productivity. This study examined the impact of grazing intensity on vegetation across a broad climatic gradient spanning the Espinal, Argentine Low Monte, and Patagonian Steppe ecoregions of Argentina. The research was carried out at eight sampling sites with radial grazing gradients generated around artificial water sources (piospheres), exhibiting two contrasting response patterns of vegetation to grazing pressure. One of the response patterns shows a typical vegetation response to grazing that the vegetation productivity increases with the distance to the water sources (decreasing grazing intensity). The second pattern is found in drier regions, where vegetation presents an inverse productivity response that vegetation productivity is higher near water sources (high grazing intensity) due to increased shrub cover. Vegetation productivity was measured using the Normalized Difference Vegetation Index (NDVI). Vegetation patch structure and cover were determined for each site with high, medium, and low grazing intensities. Results indicated that shrub cover is the primary driver of vegetation productivity, showing contrasting responses to grazing intensity between the two identified patterns. While NDVI proved to be a reliable proxy for shrub cover and total vegetation cover (R²>0.70), it failed to reflect grass cover dynamics. Furthermore, mean annual temperature was more strongly correlated with vegetation cover changes, while grazing intensity significantly altered vegetation patch structure and soil cover distribution. Specifically, in drier regions, high grazing intensity led to larger patches while, in wetter regions, it led to smaller patches (fragmentation). Shrubs, with their deeper roots and drought tolerance, were less preferred and more resistant to grazing in arid environments and thrived under grazing pressure in these arid conditions. Our results underscored the need for adaptive management strategies in grazing systems. Traditional approaches may require significant adjustments, as the efficacy of management hinges on the interplay of specific climatic conditions and the varied responses of vegetation. Furthermore, effective conservation efforts should prioritize the recognition and protection of shrubs given their critical contribution to ecosystem function and biodiversity. Ultimately, this research provides a valuable framework to understand the complex dynamics between grazing and vegetation in arid and semi-arid environments, highlighting that sustainable grazing practices should be tailored to account for both climatic variables and the unique characteristics of different plant communities.

Sand dust belts span approximately one-fifth of the global land surface. In these regions, dust tends to settle on vegetation surfaces, altering the observed reflectance and affecting remote sensing detections. To enhance the accuracy of maize growth monitoring in dust-affected regions, this study aims to quantify the effect of sand dust retention on maize during the tasseling stage in the Kashgar Prefecture, Xinjiang Uygur Autonomous Region, China, by analyzing changes in canopy reflectance and vegetation indices. First, field sampling was conducted to measure the key canopy structure parameters and dust retention levels of maize, and laboratory spectral measurements were performed on leaf spectral properties under gradient dust retention. The measured data were then used to drive the LargE-Scale remote sensing data and image Simulation framework (LESS) model for simulating realistic maize canopy spectra across different dust levels, with validation against Sentinel-2 imagery. Second, on the basis of the simulated and satellite-derived spectra, the dust resistance of 36 common vegetation indices was systematically evaluated, and new robust dust-resistant indices were developed. The results showed that compared with dust-free maize, the canopy reflectance of dust-retained maize followed an increase-decrease-increase pattern, with critical turning points at 735 and 1325 nm. The maximum reflectance difference of -0.11755 (change rate: 29.002%) occurred within the 735-1325 nm range at 24 g/m² dust retention, and the minimum reflectance difference of 0.04285 (change rate: 148.950%) was observed in the 350-735 nm range under the same dust retention level. Among the 36 vegetation indices, only the global environment monitoring index (GEMI) and the ratio of transformed chlorophyll absorption in reflectance index to optimized soil-adjusted vegetation index (TCARI/OSAVI) exhibited dust resistance, with GEMI being effective below 6 g/m² and TCARI/OSAVI remaining stable across all levels (average ratio: 0.970). The newly developed indices in this study, (RE3-RE2)/(NIR-RE2), (RE3-RE2)/(RE4-RE2), and (NIR-RE2)/(RE4-RE2), retained values within the predefined dust-resistant range over the full dust retention levels of 0-24 g/m², thus showing a more stable dust resistance compared with the commonly used 36 vegetation indices. Specially, (RE3-RE2)/(RE4-RE2) performed the most robustly in Sentinel-2 imagery, that is, 58.020% of pixels were within the dust-resistant range, and an average ratio of 0.937 was obtained for the original-spectra index. This study provides a scientific basis for crop monitoring and management in dust-affected regions.

Rising temperatures and increased droughts caused by climate change significantly reduce crop yields. Halophytes with different photosynthetic metabolism types have specific mechanisms for resistance to climatic factors. This study analyzed the morphophysiological, biochemical, and molecular-genetic mechanisms of tolerance and adaptation in halophytes, promising candidates for the restoration of salt affected lands in arid and semi-arid areas. Experiments under drought (D) and elevated temperature (eT), as well as their combined action (eT+D), were performed on Atriplex verrucifera M. Bied. (C₃ plant) and Climacoptera crassa (M. Bieb.) Botsch. (C₄-NAD-ME plant) with different types of photosynthesis. The activity of photosystem I (PSI) and the efficiency of photosystem II (PSII) were measured, along with the expression of genes involved in the light (psaA, psaB, psbA, CAB, Fd1, PGR5, and ndhH) and dark (rbcL, Ppc2, and PPDK) reactions of photosynthesis. The content of key carboxylating enzymes ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and phosphoenolpyruvate carboxylase (PEPC), as well as the photorespiration enzyme glycine decarboxylase (GDC), were assessed. Plant growth and water-salt balance parameters, and activity of enzymes in the malate dehydrogenase (MDH) system nicotinamide adenine dinucleotide (phosphate) (NAD(P))-MDH and NAD(P)-malic enzyme (ME) were also examined. A multivariate analysis of the experimental results revealed that A. verrucifera and C. crassa were both resistant to the effects of these climatic stressors. The tolerance mechanisms of both species were significantly influenced by a high level of photosynthetic plasticity. Nevertheless, differences were observed in the protective mechanisms underlying tolerance. In the C₃ species, dissipative processes associated with non-photochemical quenching (NPQ) of PSII and MDH system enzymes (malate valves) were activated, particularly under osmotic stress. The negative effects in the C₃ plants were caused by the combined action of eT+D, which was compensated by an increased expression of rbcL, psaA, CAB, and especially PGR5, i.e., genes encoding Rubisco large subunit and PSI components: apoproteins A, chlorophyll a/b-associated protein (CAB) of light-harvesting complex, and proton gradient regulation 5 (PGR5) protein of the main pathway of cyclic electron transport (CET) around PSI. In C₄ species, the protective MDH complex was expressed to a lesser extent, but activation of the C₄ carbon-concentrating mechanism (CCM) and upregulation of PGR5 expression were observed, particularly under the individual action of the factors. Under the combined stress of eT+D, C. crassa exhibited a synergistic effect, where the increase in NPQ level and NAD-ME activity, as well as decrease in NADP-ME activity was less pronounced compared with the effect of singular factors. Comparative physiological, biochemical, and molecular analyses of how C₃ and C₄ species response to individual and combined climatic factors provide new insights into sustainable plant adaptation strategies in the face of global climate change. Considering the high nutritional value of these two fodder species, a technological approach could be developed to improve the productivity of salt affected lands.

Belowground bud banks are essential for the regeneration of plant population in arid desert areas, and their response to environmental changes could reflect adaptive strategies of plants to desert habitats. However, the size and composition of belowground bud banks and their response to environmental factors in the desert steppe zone remain poorly understood, challenging desertification control efforts in arid desert areas. This study examined the density and vertical distribution of horizontal and vertical rhizome buds of a rhizomatous legume herb Sophora alopecuroides L., its population characteristics, and soil physical-chemical properties in three habitats (interdune lowland (IL), flat sandy land (FSL), and desert steppe (DS)) in a desert steppe zone, northern China. Our findings revealed that: (1) total and horizontal rhizome bud densities of S. alopecuroides differed significantly among the three habitats (P<0.05), with the largest total rhizome bud density (177 buds/m²) in IL and the smallest (63 buds/m²) in DS; (2) horizontal rhizome buds distributed in the deep soil layer were dominant in IL, while vertical rhizome buds in the top soil layer were predominant in DS; and (3) soil coarse sand, nutrient content, and population density were the primary factors affecting bud bank density of S. alopecuroides. Specifically, horizontal rhizome buds were dependent largely on soil coarse sand content, and vertical rhizome buds tended to be more related to soil organic matter content and population density. Our results indicated that horizontal rhizome buds were more important in IL with frequent aeolian disturbance, whereas vertical rhizome buds were more important in DS with abundant water and nutrient resources. The plastic responses and survival strategies of S. alopecuroides bud bank to different habitats provide valuable information for the effective implementation of desertification control measures and the management of desert steppe ecosystems.

Soil bacteria are integral to ecosystem functioning, significantly contributing to nutrients cycling and organic matter decomposition, and enhancing soil structure. This research considered the composition and dynamics of soil bacterial communities under different vegetation types (native Quercus brantii Lindl. and Amygdalus scoparia Spach, and non-native Pinus eldarica Medw. and Cupressus arizonica Greene.) in Zagros mountain area of Iran. This study involved a comparative analysis of soil culturable heterotrophic bacterial communities in spring (wet season) and summer (dry season) to clarify the effects of seasonal changes and vegetation on the dynamics of soil microorganisms. Soil samples were randomly collected under the canopies of various tree species and a control area, yielding a total of 48 composite samples analyzed for bacterial composition. Results indicated that 11 Gram-negative (e.g., Citrobacter freundii, Enterobacter cloacae, Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae, etc.) and 2 Gram-positive (Staphylococcus epidermidis and Staphylococcus aureus) bacteria were identified, showing significant seasonal variation. Specifically, 53.85% of bacterial species were common to both seasons, with notable shifts in community composition observed between spring and summer, highlighting a higher abundance of Gram-negative species in spring. Bacterial community structure was significantly influenced by vegetation type, with various tree species shaping distinct microbial assemblages. Moreover, Pearson's correlations revealed that soil properties, particularly pH, phosphorus, and moisture content, were critical drivers of bacterial diversity and abundance. Our findings underscore the dynamic nature of soil bacterial communities in response to seasonal and vegetation changes, emphasizing the importance of repeated temporal sampling for accurate assessments of microbial diversity. Understanding these microbial dynamics is essential for improving soil management strategies and enhancing ecosystem resilience, particularly in arid and semi-arid areas where environmental fluctuations play a pivotal role. This research not only confirms our hypotheses but also enhances our understanding of soil biogeochemical processes and informs future vegetation management practices.