Search Results (58)

The development of arid-oasis agriculture and territorial spatial restructuring strongly influence regional eco-environmental quality. Clarifying production–living–ecological space (PLES) transitions and the nonlinear mechanisms driving eco-environmental quality is important for sustainable agricultural land use and ecological governance. Northern Xinjiang combines economic agglomeration with ecological sensitivity, making it a representative region for examining changes in eco-environmental quality and their underlying drivers. Land-use data for 1990, 2000, 2010, and 2020 were analyzed using land-use transition matrices, the eco-environmental quality index (EEQI), spatial autocorrelation, and hotspot analysis to characterize spatiotemporal changes under PLES transitions. XGBoost–SHAP was applied to identify the dominant factors, nonlinear responses, and interactions. The results showed that: (1) ecological space remained dominant from 1990 to 2020, but its share declined from 91.72% to 87.36%. Production and living spaces increased from 7.78% and 0.50% to 11.72% and 0.92%, respectively. Agricultural production space expanded most markedly, and spatial restructuring was most intense during 2000–2010. (2) EEQI decreased from 0.3100 to 0.2922 and showed an overall fluctuating decline. Significant spatial clustering was observed, with Moran’s I values consistently above 0.81 (p < 0.001). High-value areas were mainly distributed in the Ili River Valley and along the northern slope of the Tianshan Mountains, whereas low-value areas were concentrated in the Junggar Basin interior and the arid areas along its eastern margin. (3) During 2000–2020, LAI and NPP in agricultural production space increased by 45.7% and 48.2%, respectively. These increases indicated overall improvements in canopy condition and productivity. After 2010, NPP growth slowed markedly while LAI remained relatively stable, indicating a stage-specific divergence. (4) XGBoost–SHAP showed good robustness and spatial generalizability, with R² values of 0.868–0.918 and RMSE values of 0.059–0.075. NDVI remained the primary driver, while Elev contributed consistently. The dominant interaction shifted from NDVI ∩ PopDen in 1990 and 2000 to NDVI ∩ Elev in 2010 and NDVI ∩ GDP in 2020. This shift indicated fundamental natural constraints and stronger joint effects of population and economic activities during the later stages. These findings provide a scientific basis for optimizing PLES, regulating arid-oasis agriculture, and safeguarding regional ecological security. Full article

The propagation of meteorological drought into agricultural drought is a critical stage in drought hazard development and risk accumulation. Characterizing its spatiotemporal evolution, propagation processes, and triggering conditions is therefore essential for agricultural drought mitigation and water-resource regulation in arid regions. Taking the northern slope of the Tianshan Mountains in Xinjiang, China, as the study area, this study used monthly ERA5-Land reanalysis data from the European Centre for Medium-Range Weather Forecasts for 1980–2022 to derive the Standardized Precipitation Evapotranspiration Index and Standardized Soil Moisture Index. Three-dimensional drought-event identification, the Mann–Kendall trend test, cross-wavelet transform, wavelet coherence analysis, and Copula analysis were integrated to investigate drought dynamics, multiscale propagation, and triggering thresholds. This event–process–threshold framework links individual drought-event evolution with lagged propagation characteristics and probabilistic triggering conditions, extending previous studies that focused primarily on correlation or propagation time. The results showed that a total of 92 meteorological drought events and 65 agricultural drought events were identified, with agricultural droughts generally exhibiting greater persistence and cumulative severity. Meteorological droughts were concentrated mainly in the central-eastern region, whereas agricultural droughts occurred predominantly across the western-to-central agro-pastoral ecotone. The two drought types exhibited predominantly in-phase coupling, with dominant propagation periods of 2–8 months, particularly 3–6 months, and agricultural drought generally lagging meteorological drought by 1–3 months. Propagation was fastest in summer, most persistent in autumn, and comparatively weak in winter. Propagation probability increased markedly with meteorological-drought severity, while the triggering threshold ranged from −0.81 to −0.71 and exhibited pronounced seasonal and spatial heterogeneity. These findings provide quantitative criteria for tiered drought early warning. The identified propagation periods and thresholds can support timely soil-moisture monitoring, irrigation preparation, and seasonal water allocation before meteorological drought develops into severe agricultural drought, particularly during sensitive crop-growth stages and in vulnerable oasis-agricultural areas. Full article

The Temperature-Vegetation-Precipitation Drought Index (TVPDI) performs poorly in complex terrain due to Normalized Difference Vegetation Index (NDVI) saturation and land surface temperature (LST) retrieval inaccuracies. To address this, we adopted an improved TVPDI (ITVPDI) by incorporating Leaf Area Index (LAI) and the land surface–air temperature difference (LST−T). By using multi-source data from 2000 to 2022 in Xinjiang, China, we validated ITVPDI and analyzed drought dynamics. Results show: (1) ITVPDI correlates better with solar-induced chlorophyll fluorescence (SIF) (r = 0.17) and the moisture index (MI) (r = 0.22) than the traditional TVPDI, demonstrating superior performance in densely vegetated and topographically complex areas. (2) Drought frequency ranked as follows: severe (31.55%) > moderate (29.04%) > extreme (23.44%) > mild (15.94%). Mild and moderate droughts occurred in Northern Xinjiang and the Tianshan Mountains, while severe and extreme droughts clustered around the Tarim Basin and Eastern Xinjiang desert margins. As drought intensity increases, its center of gravity shifts “from north to south” and “from mountains to basins.” (3) ITVPDI showed a slight upward trend over the 23-year period, with autumn experiencing the most severe drought (mean ITVPDI = 0.293). (4) A mean Hurst index of 0.468 indicates weak anti-persistence, suggesting the current wetting trend may reverse, and increasing future drought risk. The ITVPDI proves to be a robust tool for drought monitoring in arid and semi-arid regions with complex terrain. This study provides crucial scientific support for regional water resource allocation, precision irrigation, and collaborative drought resistance and disaster mitigation in Northwest China. Full article

Dasyhippus barbipes (Fischer von Waldheim, 1846) is an early dominant grasshopper in Chinese grasslands, and understanding its climatic niche is important for monitoring and early warning. Based on nationwide field surveys conducted from 2019 to 2024, 732 filtered occurrence records were used with an optimized MaxEnt model parameters (rm = 1.5, fc = LQ) to predict the current and future suitable habitat of D. barbipes in China. The model performed well (mean AUC = 0.962, mean TSS = 0.924). The mean temperature of the coldest quarter and precipitation seasonality were the most important limiting variables, while elevation and human footprint also contributed to habitat suitability. Under current climate conditions, suitable habitat is concentrated mainly in central and eastern Inner Mongolia, with additional suitable areas in the eastern Tianshan Mountains of Xinjiang and the central Qilian Mountains of Gansu; the highly suitable habitat covers 6.57 × 10⁴ km². Under all future climate scenarios, suitable habitat is projected to shift northward, and stable areas are mainly located in eastern Inner Mongolia. Habitat changes become more pronounced by the 2090s. These results improve understanding of the spatiotemporal dynamics of D. barbipes under climate change and provide a basis for future monitoring and management. Full article

Trees in arid mountainous forests adapt to seasonal water variability through dynamic eco-physiological adjustments. This study investigated the spatiotemporal dynamics and environmental drivers of such adaptations in Picea schrenkiana Fisch. et Mey, a keystone conifer in China’s Tianshan Mountains. We monitored key indicators—including osmoregulatory substances, antioxidant enzyme activities, and stoichiometric traits—across three regions (eastern, central, western) and three seasons (spring, summer, autumn) during the 2023 growing season. The results revealed significant seasonal shifts in all the measured traits (p < 0.05). Spring was characterized by high carbon allocation toward soluble sugars and starch, supporting growth; summer triggered elevated antioxidant enzyme activities to mitigate oxidative stress; and autumn favored nitrogen accumulation and proline synthesis, indicating preparatory storage for winter. Soil factors were primarily positively associated with antioxidant enzyme activity (path coefficient = 0.51; p < 0.001), whereas microenvironmental factors were more complex and often negatively correlated. The partial least squares path model confirmed that osmoregulatory substances centrally link stoichiometric adjustments with antioxidant defense, revealing an integrated physiological strategy. These findings elucidate the mechanism underlying the resilience of P. schrenkiana in arid highlands and provide a framework for its conservation under environmental change. Full article

Saussurea involucrata is a rare perennial herb endemic to the alpine zone of the Tianshan Mountains, possessing significant medicinal value yet facing severe threats from overharvesting and habitat fragmentation. The core distribution area and recognized genetic differentiation center of this species are located in the Bayinbuluke region of the Western Tianshan Mountains. In contrast, the genetic distinctiveness and conservation status of populations in the Eastern Tianshan Mountains have remained unclear. To clarify the genetic relationships, we conducted an integrated analysis using nuclear microsatellite (SSR) markers as well as chloroplast (cpDNA) and nuclear ribosomal DNA (nrDNA) sequences on 16 populations (5 from the Eastern Tianshan Mountains and 11 from the Bayinbuluke region). The results showed that the Eastern Tianshan Mountains populations exhibited higher genetic diversity (mean He = 0.5568). Bayesian clustering and principal coordinate analysis (PCoA) clearly separated all populations into two genetic groups corresponding to the two geographical regions. Notably, private haplotypes (cpDNA H1 and nrDNA H7) were identified exclusively in the Eastern Tianshan populations, and no recent genetic bottleneck was detected, indicating historical demographic stability. These findings demonstrate significant genetic differentiation and a unique evolutionary trajectory in the Eastern Tianshan Mountains populations, likely resulting from long-term geographical isolation and local adaptation to arid environments. Therefore, we propose that these populations be managed as an independent Management Unit (MU) to preserve their unique genetic legacy. This study provides critical genetic evidence for refining conservation strategies and promoting the sustainable use of this endangered species, while the established molecular marker system also offers a reliable framework for its geographical traceability. Full article

Net Primary Productivity (NPP) stands as a crucial metric for evaluating the condition and performance of terrestrial ecosystems. This study focuses on northern Xinjiang, China, as the research site. By employing the Carnegie Ames Stanford Approach (CASA) model alongside meteorological data, we examined the spatiotemporal variations in vegetation NPP from 2001 to 2022. The model utilized monthly NDVI, climate drivers, and vegetation type raster data as inputs, while the Mann–Kendall test, We utilized Theil–Sen trend analysis and residual analysis to investigate how climatic factors and human activities drove NPP changes. Results show that from 2001 to 2022, vegetation NPP in northern Xinjiang generally rose with fluctuations, averaging 127.96 gC·m⁻²·a⁻¹ annually and growing linearly at 0.58 gC·m⁻²·a⁻¹. Spatially, NPP displayed a pattern of “high in the west and low in the east, high in mountainous areas and low in deserts.” High NPP areas are mainly clustered in the Ili River Valley and adjacent mountainous regions, encompassing eastern and southwestern Ili Prefecture, northern Tianshan slopes, Balq Mountains, and southern Borokunu foothills, where hydrothermal conditions are relatively advantageous. In the last 22 years, the mean temperature in northern Xinjiang showed a fluctuating upward trend, precipitation exhibited a fluctuating downward trend, and solar radiation demonstrated a significant declining trend. Partial correlation analysis revealed that, compared with temperature and solar radiation, precipitation had a stronger positive correlation with NPP. Residual analysis showed that in areas where vegetation NPP exhibited recovery, human activities were the dominant driving factor, accounting for 23.58% of the total area, whereas the influence of climate change was relatively minor. Conversely, in regions where vegetation NPP degraded, climate change exerted a greater impact than human activities. This research clarifies the combined impacts of climate and human actions on ecosystem productivity in arid areas, offering a scientific foundation and reference for ecological protection and regional carbon control in such regions. This provides a scientific basis for formulating rational response strategies to restore vegetation and enhance the quality of ecosystems in arid regions. Full article

As direct geomorphic evidence and records of earthquakes on the surface, coseismic surface ruptures have long been a key focus in earthquake research. However, compared with strike-slip and normal faults, studies on reverse-fault surface ruptures remain relatively scarce. In this study, surface rupture characteristics of the most recent earthquake on the Kumysh thrust fault in eastern Tianshan were investigated using high-resolution topographic data, including 0.5 m- and 5 cm-resolution Digital Elevation Models (DEMs) generated from the WorldView-2 satellite stereo image pairs and Unmanned Aerial Vehicle (UAV) images, respectively. We carefully mapped the spatial geometry of the surface rupture and measured 120 vertical displacements along the rupture strike. Using the moving-window method and statistical analysis, both moving-mean and moving-maximum coseismic displacement curves were obtained for the entire rupture zone. Results show that the most recent rupture on the Kumysh Fault extends ~25 km with an overall NWW strike, exhibits complex spatial geometry, and can be subdivided into five secondary segments, which are discontinuously distributed in arcuate shapes across both piedmont alluvial fans and mountain fronts. Reverse fault scarps dominate the rupture pattern. The along-strike coseismic displacements generally form three asymmetric triangles, with an average displacement of 0.9–1.1 m and a maximum displacement of 2.8–3.2 m, yielding an estimated earthquake magnitude of M_w 6.6–6.7. This study not only highlights the strong potential of high-resolution remote sensing data for investigating surface earthquake ruptures, but also provides an additional example to the relatively underexplored reverse-fault surface ruptures. Full article

Investigating the diurnal variation characteristics of precipitation (DVCP) in Xinjiang, an arid region of Northwest China, is essential for improving water resource management and disaster mitigation strategies. This study examines the DVCP associated with diverse underlying surfaces in Eastern Xinjiang (EX)—one of the most arid regions in China—during summer (June–August) from 2015 to 2019, using hourly simulation data from the real-time forecasting system of Nanjing University (WRF_NJU). Evaluation against automatic weather station (AWS) observations indicates that WRF_NJU outperforms reanalysis (ERA5), satellite (CMORPH), and MESWEP datasets, demonstrating its reliability for regional precipitation analysis. Further investigation reveals that in the Turpan-Hami Basin (THB), below 1000 m above sea level (ASL), peaks in precipitation amount (PA), intensity (PI), and frequency (PF) occur at 06 local solar time (LST), whereas in mountainous areas above 3000 m ASL, these peaks are delayed until 13 LST. Analysis of the coefficient of variation (CV) shows that the most pronounced differences in DVCP between mountainous and basin regions are associated with PF and PI. Specifically, regions with high CV for PF are concentrated in the central to northern parts of the THB, while high CV for PI is found in the eastern Mid-Tianshan Mountains (MTM) and East Tianshan Mountains (ETM). Moreover, significant differences in DVCP are observed across land surface types: PA peaks over grasslands, forests, and water bodies occur around noon, whereas over impervious surfaces, croplands, and barren areas, they occur during the early morning hours. Full article

Glaciers, often regarded as “frozen reservoirs”, play a crucial role in replenishing numerous rivers in arid regions, contributing to ecological balance and managing river flow. Recently, the rapid shrinkage of the glaciers in the East Tianshan Mountains has affected the water quantity in the Karez system. However, studies on glacier changes in this region are limited, and recent data are scarce. This study utilizes annual Landsat composite images from 1990 to 2022 obtained via the Google Earth Engine (GEE). It utilizes a ratio threshold approach in conjunction with visual analysis to gather the glacier dataset specific to the Turpan–Hami region. The Open Global Glacier Model (OGGM) is used to model the flowlines and mass balance of around 300 glaciers. The study analyzes the glacier change trends, distribution characteristics, and responses to climate factors in the Turpan–Hami region over the past 30 years. Additionally, future glacier changes through the end of the century are projected using CMIP6 climate data. The findings indicate that the following: (1) From 1990 to 2022, glaciers in the research area underwent considerable retreat. The total glacier area decreased from 204.04 ± 0.887 km² to 133.52 ± 0.742 km², a reduction of 70.52 km², representing a retreat rate of 34.56%. The number of glaciers also decreased from 304 in 1990 to 236 in 2022. The glacier length decreased by an average of 7.54 m·a⁻¹, with the average mass balance at −0.34 m w.e.·a⁻¹, indicating a long-term loss of glacier mass. (2) Future projections to 2100 indicate that under three climate scenarios, the area covered by glaciers could diminish by 89%, or 99%, or even vanish entirely. In the SSP585 scenario, glaciers are projected to nearly disappear by 2057. (3) Rising temperatures and solar radiation are the primary factors driving glacier retreat in the Turpan–Hami area. Especially under high emission scenarios, climate warming will accelerate the glacier retreat process. Full article

The flood–drought severity in arid regions such as Xinjiang is increasingly influenced by climate extremes. While prior studies have explored the relationship between climate extremes and flood–drought dynamics, few have analyzed these interactions at different time and spatial scales using different method combinations. This study addresses that gap by utilizing a gridded dataset (CN05.1) during 1961–2020, examining the China Z index (flood–drought index) and climate extremes. The analysis reveals significant increases in precipitation and heat extremes, while cold extremes have decreased. In addition to overall periodic changes with 2.5 and 8 years in the flood–drought severity, our results demonstrate a significant spatial shift between 1981 and 2000 and between 2001 and 2020. Previously flood-dominant regions, including portions of the Junggar Basin, Eastern Tianshan Mountains, and Tarim River Basin, transitioned to drought-dominant in 2001–2020. Conversely, drought-dominant regions became flood-dominant. Strong positive correlations (0.65–0.84) were found between the Z index and precipitation extremes, while temperature extremes showed weaker correlations. Furthermore, we applied six variable selection regression methods, with Random Forest variable selection + Random Forest regression (RF+RF) performing the best (mean R² = 0.71), highlighting their ability to manage non-linear relationships and multicollinearity between climate indices. RF+RF proved more effective at handling correlated variables, which were crucial in capturing the region’s flood–drought dynamics. The quantified spatial reversals and non-linear climate-flood/drought relationships provide actionable metrics for early warning systems, enabling targeted infrastructure upgrades and water allocation policies in arid regions. These findings establish a transferable framework linking climate extremes to hydrological risks, directly informing adaptive land management and disaster preparedness strategies for Xinjiang and analogous regions under intensifying climate variability. Full article

“Production–Living–Ecological” spatial conflicts (PLECs) are critical issues arising from regional land development, affecting economic, social, and ecological security. Identifying and analyzing these conflicts’ spatiotemporal characteristics is essential for sustainable development. This study focuses on the Tuha region, which experiences an extremely arid climate, classifying the region’s “Production–Living–Ecological” (PLE) spaces into four types: living–production, ecological–production, production–ecological, and ecological spaces. A spatial conflict measurement model based on landscape patterns was developed to analyze the evolution of PLECs from 2000 to 2020. Additionally, the PLUS model was used to simulate PLEC patterns in 2030 under different development scenarios. The results indicate that between 2000 and 2020, the area proportions in the Tuha region ranked from largest to smallest as follows: ecological space, ecological–production space, production–ecological space, and living–production space. The area of living–production space increased, while production–ecological space first increased and then stabilized, and the areas of ecological and ecological–production spaces decreased. From 2000 to 2020, spatial conflicts in the region were predominantly characterized by mild weak conflicts. High–high PLEC clusters were concentrated in urban and surrounding areas of Gaochang District, Toksun County, Shanshan County, and Yizhou District, while low–low clusters were found in the Eastern Tianshan Mountains and northern Barkol Kazakh Autonomous County. NDVI, GDP, population, and proximity to roads positively influenced PLECs, while elevation, slope, aspect, and precipitation had inhibitory effects. Under different development scenarios, the natural development scenario leads to the most severe spatial conflicts, while the cropland protection scenario reduces PLECs and enhances regional welfare, making it the optimal pathway for future development. Full article

Awulale Mountain is one of the most important Fe-Cu concentration areas situated in the eastern part of Western Tianshan. The Cu deposits in the belt are genetically associated with the Permian intermediate and felsic intrusions. However, the precise age and magma source of the causative intrusions are currently not confirmed, constraining our understanding of regional mineralization. The Cahanwusu porphyry Cu deposit is located in the western part of Awulale Mountain. Field investigations have shown that the mineralization in the deposit is genetically associated with granitic porphyry and diorite porphyry. In this paper, we provide detailed zircon U-Pb ages and in-situ Hf isotopic compositions of the granitic porphyry and diorite porphyry. The granitic porphyry and diorite porphyry have zircon U-Pb ages of 328.6 ± 2.6 Ma (MSWD = 0.52; n = 23) and 331 ± 2.8 Ma (MSWD = 0.95; n = 21), respectively. This indicates that the Cahanwusu deposit was formed in the Carboniferous in a subduction setting. This is distinguishable from other porphyry Cu deposits in the belt, which were generally formed in the Permian in the post-collision extensional setting. The granitic porphyry and diorite porphyry exhibit positive ε_Hf(t) values varying from +2.8 to +5.4 (average of +4.1) and +2.0 to +5.1 (average of +4.1), respectively. The magmas of these causative intrusions were interpreted to be derived from the partial melting of the juvenile lower crust which originated from cooling of mantle-derived magmas related to the subduction process. Our new results highlight that the Cahanwusu deposit represents a new episode of Cu mineralization in the belt and the Carboniferous granitoids in Awulale Mountain are potential candidates for Cu exploration. Full article

The Tianshan Mountains are located in the hinterland of the Eurasian continent, spanning east to west across China, Kazakhstan, Kyrgyzstan, and Uzbekistan. As the primary water source for Central Asia’s arid regions, the Tianshan mountain system is pivotal for regional water security and is highly sensitive to the nuances of climate change. Utilizing ERA5 precipitation datasets alongside 24 atmospheric circulation indices, this study delves into the variances in Tianshan’s precipitation patterns and their correlation with large-scale atmospheric circulation within the timeframe of 1981 to 2020. We observe a seasonally driven dichotomy, with the mountains exhibiting increasing moisture during the spring, summer, and autumn months, contrasted by drier conditions in winter. There is a pronounced spatial variability; the western and northern reaches exhibit more pronounced increases in precipitation compared to their eastern and southern counterparts. Influences on Tianshan’s precipitation patterns are multifaceted, with significant factors including the North Pacific Pattern (NP), Trans-Niño Index (TNI), Tropical Northern Atlantic Index (TNA*), Extreme Eastern Tropical Pacific SST (Niño 1+2*), North Tropical Atlantic SST Index (NTA), Central Tropical Pacific SST (Niño 4*), Tripole Index for the Interdecadal Pacific Oscillation [TPI(IPO)], and the Western Hemisphere Warm Pool (WHWP*). Notably, NP and TNI emerge as the predominant factors driving the upsurge in precipitation. The study further reveals a lagged response of precipitation to atmospheric circulatory patterns, underpinning complex correlations and resonance cycles of varying magnitudes. Our findings offer valuable insights for forecasting precipitation trends in mountainous terrains amidst the ongoing shifts in global climate conditions. Full article

Revealing the relationship between intensive land use (ILU) and land ecological security (LES) is crucial for achieving high-quality land resource development and ensuring the sustainability of land ecosystems, especially in arid regions with fragile human–land relationships. In this study, we evaluated ILU and LES in the urban agglomeration on the northern slope of the Tianshan Mountains (UANSTM) and analyzed the evolution of ILU and LES using Pearson correlation analysis, four-quadrant model, and coupling coordination degree model. The results indicated that from 2012 to 2022, ILU and its three subsystems generally showed an upward trend in the UANSTM, with an average annual growth rate of 2.96%, 2.50%, 3.32%, and 0.289%, respectively, and with ILU levels significantly higher in the eastern and central counties compared to other areas. LES and its three subsystems also exhibited a general increase, with average annual growth rates of 1.63%, 0.86%, 3.10%, and 1.51%, respectively, although high-level areas displayed distinct spatial variations. The Pearson correlation analysis showed that the land input level had a significant negative effect on the pressure, but the positive effects of state and response enhanced the LES. The number of double-high cities increased significantly from 1 to 6, and the number of double-low cities decreased from 6 to 0. Compared with other cities and counties, the LES-lagging counties and cities faced the challenge of coordinating urban development and ecological conservation. While coupling coordination levels across all counties improved to varying degrees, none reached the optimal coordination stage. The findings and methodologies of this study provide helpful insights into human–land relationships in arid regions, supporting the goals of high-quality urban development and sustainability. Full article