Search Results (437)

Ensuring the long-term sustainable utilisation of supplemented cropland has become a critical challenge for implementing China’s requisition–compensation balance of farmland (RCBF) policy, particularly in the fragmented hilly and mountainous regions of Southwest China. Existing studies generally evaluate land suitability and utilisation performance separately, making it difficult to identify mismatches between theoretical suitability and actual utilisation and thereby limiting targeted regulation. To address this limitation, this study proposes a suitability–utilisation deviation identification (SUDI) framework, which integrates four sequential analytical components: three-dimensional suitability assessment, suitability–utilisation deviation identification, driving mechanism analysis, and sustainable regulation. Taking Beibei District of Chongqing as a case study, supplemented cropland parcels were identified using the 2020–2024 land change survey data. A three-dimensional suitability evaluation system incorporating production, ecological, and utilisation attributes was established to quantify theoretical land suitability. Actual utilisation performance was characterised using the land economic utilisation coefficient, and suitability–utilisation deviation was identified through residual analysis between theoretical suitability and utilisation intensity. A Bayesian-optimised Extreme Gradient Boosting-SHAP (XGBoost-SHAP) model was subsequently employed to reveal the nonlinear effects and interaction mechanisms of the driving factors. The results indicate the following: (1) supplemented cropland in Beibei District is predominantly characterised by medium-to-high suitability, with high-suitability patches exhibiting a mosaic spatial pattern of local aggregation and overall dispersion; (2) suitability–utilisation deviation is dominated by under-utilised plots, whereas well-matched and over-intensified plots account for substantially smaller proportions, indicating that insufficient realisation of land suitability is the prevailing utilisation pattern; and (3) the land economic utilisation coefficient is the dominant factor driving suitability–utilisation deviation, while high-standard farmland construction and plot area exhibit significant mitigating effects. Moreover, significant interaction effects between utilisation intensity and location-related variables reveal that unfavourable spatial conditions amplify deviation risk under intensive land use. The proposed SUDI framework extends conventional suitability assessment by explicitly linking suitability evaluation with utilisation performance, driving mechanism analysis, and differentiated regulation. It provides a transferable analytical framework for diagnosing suitability–utilisation mismatch and supports dynamic management and sustainable utilisation of supplemented cropland in fragmented hilly and mountainous regions. Full article

Nitrogen dioxide (NO₂) drives ozone and secondary aerosol formation and harms human health. Chongqing, a mountainous megacity of 32 million people, lacks a fine-scale satellite assessment of its NO₂ evolution. We analyzed tropospheric NO₂ vertical column density (VCD) over Chongqing for 2019–2024. The analysis used Sentinel-5P TROPOMI observations. We computed monthly, seasonal, and annual composites at 5.5 km resolution. Trends were quantified with the Theil–Sen slope and, at the pixel level, the Seasonal Mann–Kendall (SMK) test applied to the full 72-month series. A MODIS land-cover mask separated urban built-up from non-urban pixels. NO₂ concentrated in the central districts and along the Yangtze valley. The core exceeded the mountainous counties by a factor of 3 to 4. TROPOMI resolved the Wanzhou and Yongchuan–Jiangjin hotspots as separate features. The record was divided into three phases. The 2020 lockdown produced the minimum, 31% below the prior February. Rebound emissions produced the 2021 maximum of 5.6 × 10¹⁵ molecules cm⁻² under near-normal dispersion conditions, with ERA5 (the European Centre of Medium-range Weather Forecasts Reanalysis v.5) showing the January 2021 boundary layer 4.3% deeper than its climatological norm. Thereafter the regional mean stabilized: the area-weighted SMK slope was +0.042 × 10¹⁵ molecules cm⁻² yr⁻¹ and not significant (p = 0.14), because emission controls in the core and rising county emissions canceled in the average. Trends diverged sharply in space. The nine core districts declined (median urban Sen slope −0.11 × 10¹⁵ molecules cm⁻² yr⁻¹), whereas 41% of peripheral pixels rose significantly (p < 0.05). The urban-to-rural ratio narrowed from 3.0 in 2019 to 2.3 in 2024 (annual means). This convergence was robust to the built-up threshold (30–50%). Industrial relocation and county urbanization explain the peripheral rise. The results support extending vehicle and industrial emission standards from the core to the receiving counties. Full article

Surface albedo is crucial for the polar energy balance. Blowing snow (BLSN) frequently perturbs coastal Antarctic albedo, yet its specific radiative effects and observability by medium-resolution satellites remain poorly understood. This study combines multi-source ground observations at Zhongshan Station with Sentinel-2 and MODIS imagery to evaluate the multi-scale albedo response to BLSN. The results show that when snowfall and BLSN occur simultaneously, they generally lead to spatially uniform surface brightening. Conversely, when BLSN occurs after snowfall has ended, strong winds drive snow erosion and redistribution, producing highly dispersed, interleaved patches of local positive and negative albedo changes. Scale-bridging analysis reveals that spatially uniform brightening is reliably captured by medium-resolution satellites. However, these highly dispersed local signals extensively cancel each other out during spatial averaging. In the evaluated events, this cancellation drives the net regional signal toward zero, masking a substantial local surface shortwave radiative forcing that, at solar noon, can reach tens to over a hundred W m⁻². This study suggests that the observability of dynamic surface perturbations depends on their sub-pixel spatial structure. Consequently, a near-zero signal at medium resolutions does not guarantee an unchanged surface, highlighting a hidden cancellation effect that obscures critical local energy redistributions. Full article

This study presents a multivariate spatio-temporal clustering framework to characterise joint wind–wave regimes across European seas using the fifth-generation atmospheric reanalysis produced by the European Centre for Medium-Range Weather Forecasts (ERA5; 1979–2014). Seasonal and annual statistics of significant wave height, mean wave period, wind speed, and wave/wind direction were computed at 0.5° resolution. Principal component analysis was used to reduce dimensionality, retaining 30 components that captured 99% of the variance. K-means clustering was then used to identify nine coherent dynamical regimes with persistent spatio-temporal signatures. These regimes were grouped into open-ocean, transitional, and enclosed/semi-enclosed categories based on internal variability, directional spread, and geographic exposure. Open-Atlantic regimes are found to be energy-rich, exhibiting clear December–February maxima in significant wave height ($H_s$), mean wave period ($T_{02}$), and 10 m wind speed ($W_{s10}$); enclosed and semi-enclosed basins show lower amplitudes and reduced variability, while transitional shelves and the southern Mediterranean display intermediate conditions, characterised by moderate $T_{02}$ levels and seasonal rotation of wave and wind directions, reflecting a mixed influence of locally generated seas and remotely forced swell. Dispersion analysis highlights a clear Atlantic–Mediterranean partition, with transitional shelves forming a dynamical bridge between open-ocean and enclosed basins. Teleconnection analysis shows that the North Atlantic Oscillation and Arctic Oscillation dominate Atlantic regimes, while the Scandinavia, East Atlantic, and Polar/Eurasia patterns modulate variability and directional persistence in transitional and enclosed seas. The classification defines a climatological framework of European wind–wave conditions and establishes a practical basis for renewable energy assessment, engineering design, and long-term change analysis, with methods transferable to other basins. Full article

This study aimed to synthesize copper(I) iodide nanoparticles (CuI NPs) through a green route using taxo (banana passion fruit) extract as a natural capping and stabilizing agent, and to evaluate their antimicrobial performance against microorganisms isolated from concrete, together with a preliminary cytotoxicity screening. The obtained nanoparticles were characterized by ultraviolet–visible spectroscopy (UV–Vis), Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDS), dynamic light scattering (DLS), and X-ray diffraction (XRD). UV–Vis spectra recorded in the 200–704 nm range showed a strong absorption band at 224 nm, consistent with electronic transitions associated with nanostructured CuI. FTIR analysis revealed extract-derived biomolecules adsorbed on the nanoparticle surface, with bands assigned to aliphatic C–H, aromatic moieties, and C–O/C–O–C vibrations, supporting the formation of an organic capping layer. DLS analysis showed a mean hydrodynamic diameter of approximately 32 nm in aqueous suspension, whereas TEM revealed particle sizes ranging from 13 to 42 nm. XRD confirmed a predominantly cubic CuI phase, while SEM–EDS identified Cu and I as the main elements, with minor signals attributed to residual organic coating and/or trace species from the synthesis medium. The CuI NPs exhibited antimicrobial activity against microorganisms isolated from medium-strength concrete, producing inhibitory effects at all tested concentrations (0.014, 0.0087, and 0.0035 mol/L). Preliminary cytotoxicity screening using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in human foreskin fibroblast (HFF), human breast adenocarcinoma (MCF7), and human glioblastoma (U251) cell lines showed dose- and time-dependent reductions in metabolic viability. The 1.0 mol/L formulations, particularly the precipitated fraction, produced stronger cytotoxic effects, whereas the 0.1 mol/L formulations, especially the residual fraction, preserved comparatively higher metabolic viability. Overall, these findings suggest that taxo-mediated CuI NPs are promising antimicrobial candidates for concrete biodeterioration control, while further colloidal and biological studies are required to better define their behavior under cell-culture conditions and optimize their safe application. Full article

Hydrophilic osmium(Os)-based redox polymers were designed as electron-transfer mediators for fungal flavin adenine dinucleotide-dependent glucose dehydrogenase (FAD-GDH)-based glucose sensors. Poly(vinylimidazole-co-hydroxyethyl acrylate) (PVI-HEA) copolymers with different HEA compositions were synthesized and coordinated with Os(dmo-bpy)₂Cl₂ to prepare PVI-HEA-Os(dmo-bpy)₂Cl₂ redox mediators. The synthesized mediator systems were characterized using ¹H-nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, field emission scanning electron microscopy/energy dispersive spectroscopy, zeta potential analysis, cyclic voltammetry, and electrochemical impedance spectroscopy. The results confirmed the successful formation of Os redox polymer structures and their immobilization on the electrode surface. The electrochemical behavior and glucose sensing performance strongly depended on the PVI-HEA composition. Among the compositions tested, PVI-HEA(3.5:1)-Os(dmo-bpy)₂Cl₂ showed the strongest redox current response, stable aqueous dispersion behavior, and relatively low interfacial charge-transfer resistance. Glucose-sensing measurements using FAD-GDH/mediator-modified electrodes showed linear current responses over the glucose concentration range of 1.25–20 mM. The PVI-HEA(3.5:1)-Os(dmo-bpy)₂Cl₂-based electrode showed the highest sensitivity of 16.18 μA cm⁻² mM⁻¹, which was significantly higher than those observed at lower-HEA compositions. The optimized mediator system also showed selective glucose responses against representative biological interferents, including ascorbic acid, uric acid, dopamine, and serotonin. Stable catalytic current responses were maintained under Human Plasma-Like Medium conditions, suggesting improved matrix tolerance compared to conventional PVI-based Os redox polymers. The improved sensing performance was attributed to the hydrophilic polymer environment introduced by the HEA units, which may facilitate favorable interfacial charge-transfer behavior within the enzyme–mediator layer. The results show that the hydrophilic copolymer composition plays an important role in the electrochemical behavior and glucose sensing performance of Os redox polymer mediators. The proposed PVI-HEA-Os(dmo-bpy)₂Cl₂ system may be a promising candidate for future enzymatic glucose sensing and continuous glucose monitoring-related applications. Full article

In this work, we report the synthesis of a photocatalytic system based on impregnating g-C₃N₄ quantum dots (CNQDs) onto the surface of exfoliated graphitic carbon nitride (CN). The CNQDs were prepared using a top-down strategy via a hydrothermal route and then grafted onto exfoliated g-C₃N₄ under solvothermal conditions. The prepared CNQDs/CN composites were characterized using several techniques, including X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), and nitrogen physisorption. According to XPS analysis, a slight increase in the O 1s signal in the 1-CNQDs/CN sample could indicate a higher amount of adsorbed hydroxyl groups, which would favor the dispersion of the powder material in the aqueous medium. The photocatalytic degradation of the antibiotic levofloxacin (LEVO) was assessed using the CNQDs/CN samples, with the sample impregnated with 1 wt.% of CNQDs demonstrating the highest photocatalytic performance under UV-vis radiation conditions. Likewise, the 1-CNQDs/CN sample also exhibited the lowest photoluminescence emission (λ_exc = 315 nm), indicating that the presence of g- C₃N₄ quantum dots contributed to the decrease in the recombination rate of the photogenerated electron–hole pairs in the photoexcited graphitic carbon nitride. The stability tests revealed a modest performance reduction of 21% over three cycles. From the photocatalytic tests using scavenger agents, it was determined that hydroxyl (·OH) and superoxide (·O₂⁻) radicals are the reactive species that govern the levofloxacin photodegradation under experimental conditions. Consequently, we determined a photocatalytic mechanism consistent with the results. Full article

The pore system of coal reservoirs is the fundamental structural basis controlling coalbed methane adsorption, storage, diffusion, migration, and production performance. Its development characteristics are influenced not only by thermal maturity but also by maceral composition. To clarify the differences in mesopore structure and fractal characteristics of coal samples with different maceral compositions, this study focuses on the Xishanyao Formation coals in the Nileke Depression, northeastern Yili Basin. Ten coal samples were collected and analyzed using coal petrology and coal quality tests, low-temperature nitrogen adsorption experiments, and mono-fractal and multifractal characterization. The results show that the samples have R_o,max values ranging from 0.70% to 1.31%, indicating broadly comparable thermal maturity, whereas vitrinite and inertinite contents vary significantly. Accordingly, the samples can be classified into vitrinite-rich Type I and relatively low-vitrinite Type II. Low-temperature nitrogen adsorption results indicate that both types contain mesopores within the 2–100 nm range, but they differ markedly in pore-size distribution and hysteresis-loop characteristics. Type I is mainly controlled by the 10–50 nm pore-size interval and is characterized by a relatively concentrated distribution of medium-scale mesopores, whereas Type II is more strongly influenced by the 50–100 nm interval and shows a more dispersed pore distribution. Fractal analysis further reveals systematic differences between the two types in pore-surface roughness, structural complexity, and scale-dependent heterogeneity. Type I is mainly characterized by enhanced pore-structure complexity governed by medium-scale mesopores, whereas Type II is more strongly characterized by enhanced heterogeneity controlled by variations in larger-scale mesopores. Overall, differences in maceral composition influence the complexity and multiscale heterogeneity of the mesopore system by controlling the dominant pore-size intervals and pore-organization patterns. These findings provide a geological basis for reservoir evaluation of the Xishanyao Formation coals and for understanding the mechanisms of coalbed methane occurrence and migration. Full article

This study investigates the propagation characteristics of Rayleigh waves in partially saturated poroviscoelastic half-spaces based on fundamental theories of elastic wave propagation. Firstly, a poroviscoelastic model tailored to unsaturated porous media is developed, integrating constitutive relations and dynamic equilibrium equations with fractional derivatives to effectively capture the complex, history-dependent viscoelastic behavior of materials. Secondly, the potential function method is employed to derive the dispersion equation for Rayleigh waves in the proposed medium. Lastly, numerical simulations are conducted to analyze the effects of liquid saturation and fractional order parameters on Rayleigh wave velocity, with results presented through graphical illustrations. The analysis reveals that both liquid saturation and fractional order significantly influence the propagation features of Rayleigh waves. This work provides valuable theoretical support for seismic exploration and related engineering applications involving unsaturated porous formations. Full article

To address the major safety hazard that heat released from mining polyurethane (PU) reinforcement materials may induce spontaneous combustion of residual coal in goaf, this study selected No. 3 coal from Wangzhuang Coal Mine, Shanxi Lu’an, as the research object. A self-developed large-capacity, large-scale experimental system was used to conduct programmed heating experiments on 2.0 kg multi-particle-size coal-PU mixed samples. The effects of PU content on characteristic gas release, crossing point temperature (CPT), residue morphology, and TGA-DSC characteristic temperatures were systematically investigated, and the reaction-kinetic evolution was further analyzed using the distributed activation energy model (DAEM). The results show that coal and PU exhibit a significant synergistic enhancement effect during co-heating. As the PU content increased, the release concentrations of CO, C₂H₄, and C₂H₆ increased markedly, and their initial release temperatures decreased, whereas CH₄ generation was inhibited by hydrogen-radical competition; no C₂H₂ was produced below 400 °C. The CPT decreased linearly with an increasing PU content, with an average decrease of approximately 8.5 °C for every 10% increase in PU content. Residue morphology showed clear critical features: glassy agglomerates appeared when the PU content exceeded 16.67%, and dense bulk coking occurred when the PU/coal mass ratio was greater than 1:10. TGA-DSC analysis showed that when the PU/coal ratio was lower than 1:10, the ignition temperature of the mixed sample was higher than that of pure coal, indicating an inhibitory synergistic effect. When the ratio exceeded 1:10, the ignition temperature decreased significantly, and the synergy shifted to promotion; increasing the heating rate shifted the characteristic temperatures to higher values and increased the reaction intensity. DAEM analysis further confirmed that when the PU ratio exceeded 1:10, the apparent activation energy of the mixed samples was lower than that of pure coal. Coal powder also acted as a physical skeleton that effectively dispersed molten PU, eliminated the activation-energy peaks of pure PU in the conversion ranges of 30–50% and 70–90%, and substantially improved combustion stability. Mechanistically, low-temperature PU melting and coating optimized heat and mass transfer, medium-temperature pyrolysis released active radicals and combustible gases that altered coal pyrolysis pathways and the radical reaction environment, and high-temperature hydrogen-radical competition reshaped the gas-product distribution. Together, these processes form a complete chain of synergistic spontaneous combustion. This study identifies key safety threshold parameters for PU reinforcement materials, recommends a PU content of ≤9.10%, and identifies CO and C₂H₄ as priority early-warning gases, providing direct experimental evidence for characteristic-gas-based early warning and mine fire prevention. Full article

This study poses the following research question: Where and how can low- to medium-enthalpy geothermal resources in Northern México be harnessed to promote a territorially anchored, socially inclusive energy transition? Hence, the potential contribution of geothermal direct uses to sustainable local development in Sonora—one of México’s largest and most economically diverse states—is examined in this article. In Sonora, a semi-arid region with dispersed populations and underutilized geothermal resources, the research integrates spatial analysis and socio-territorial indicators to identify areas where geothermal direct uses can deliver inclusive development benefits. Thermal data of 88 thermal springs and 36 wellbores were examined, in which in situ temperatures and geothermal gradients were found from 30 to 80 °C and 20–200 °C/km, respectively. This resulted in a catalog of 28 direct uses based on the energy needs and demands of the population near the sites. Then, a composite methodological framework was developed that combined the Geothermal Suitability Index (GSI), the Socio-Productive Energy Demand Index (SPEDI), and the Territorial Vulnerability Index (TVI). These indices and the catalog were overlaid to detect municipalities where high geothermal potential, energy needs, and social vulnerability intersect. Results show that sites such as Bacadehuachi, Cajeme, and Fronteras offer high-priority opportunities for agri-food processing, aquaculture, and heating/cooling applications. The findings contribute to broader debates on rural energy access, energy justice, and decentralized planning, providing evidence-based guidance for policy design that aligns renewable energy deployment with regional equity and resilience goals. Full article

In this study, Prunus dulcis hull (PDH) has been used to develop a cost-effective and eco-friendly adsorbent material for the removal of Pb²⁺ ions from polluted waters. The PDH particles were characterized using various techniques, including ATR-FTIR spectroscopy, ion-selective electrode ISE-H⁺ potentiometric titrations, pH of point of zero charge (pH_pzc) analysis, thermogravimetric analysis (TGA), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). Single-batch adsorption experiments were conducted at different pH values, with pH 5.0 identified as the optimal initial pH in terms of Pb²⁺ adsorption performance of PDH. The study also evaluated the effects of temperature, ionic medium, and several organic ligands with different functional groups on the adsorption capacity of PDH. The results showed that PDH is an effective adsorbent for lead ions, with adsorption capacities (q_m) ranging from 43 to 101 mg g⁻¹ and an adsorption equilibrium time of approximately 750 min at room temperature. Additionally, column adsorption experiments demonstrated that PDH can be reused at least four times with minimal loss in performance. The adsorption behavior of PDH was comparable under both equilibrium (batch) and non-equilibrium (column) conditions, with the breakthrough time (BT_0.5) values significantly affected by the background salts present in the toxic metal ion solution. Full article

This study employs a multiscale theoretical approach to systematically investigate the thermal stability, phase transition characteristics, and pyrolysis product distributions of four long-chain n-alkanes ranging from n-dodecane to n-pentadecane (C12–C15). At the electronic structure level, density functional theory calculations reveal that with increasing chain length, the HOMO–LUMO gap narrows monotonically from 8.87 eV to 8.77 eV and global softness increases, indicating enhanced electronic responsiveness to thermal perturbation. Molecular electrostatic potential analysis shows decreasing surface potential variance and 100% nonpolar surface area across all species, confirming that intermolecular interactions are exclusively governed by London dispersion forces. At the condensed-phase level, semiempirical quantum-based molecular dynamics (xTB-MD) simulations at 3500 K over 6 ps trajectories reveal qualitative chain-length-dependent initial bond-breaking patterns: C2 species appear prominently among early fragments for C12–C15 systems, with medium-sized fragments (C3, C4) becoming increasingly prevalent and C1 species relatively less prominent as chain length grows. This work provides an integrated “electronic structure-condensed phase transition-pyrolysis kinetics” perspective, offering precise theoretical insights and critical benchmark data for the pyrolysis mechanisms of long-chain n-alkanes. Full article

Cellulose nanofibers (CNFs) have significant potential in composites as additives to improve mechanical properties, melt rheology, and more. However, agglomeration of CNFs is a key challenge in composite melt processing as obtaining nano-level dispersion of CNFs often requires cost- and energy-intensive processes (e.g., solvent exchange or freeze drying) due to the strong hornification tendencies of CNF. Herein, we avoid these challenges by using a natural fiber carrier method to integrate CNF into thermoplastic composites. Fibers are co-dried to create a hybrid fiber feedstock for compounding in which natural fibers are decorated with dispersed nanofibers. The hybridized fibers result in up to a 24% increase in tensile strength and up to a 35% increase in Young’s modulus compared to composites only containing natural fibers. The lignocellulosic nanofibers are found to outperform their purely cellulosic counterpart, which is theorized to be due to either an increased propensity for fibrillation of the lignocellulosic fibers or the increased hydrophobicity of the fibers due to the presence of lignin. Surface analysis of fiber feedstocks, via streaming potential measurements and dynamic light scattering (DLS), confirmed a significant change in the feedstock hydrophobicity before and after hybridization. While mild additions of CNF (1 wt.% on the macroscale fiber) do not impact the composite melt viscosity, the viscosity is found to increase at higher CNF loadings (5 wt.% on the macroscale fiber), indicating its utility as a rheology modifier. Lastly, use of these materials as novel feedstocks for medium-scale additive manufacturing in high-fidelity part production was demonstrated. Full article

Revealing scale effects and the mechanisms underlying the relationships between plant species and functional diversity is crucial for understanding the stability of desert ecosystems and formulating multiscale conservation strategies. In this study, the spatial patterns of plant species and functional diversity in the Gurbantunggut Desert were analysed via multiscale grid sampling. The results indicated that (1) both species diversity and functional diversity indices exhibited high spatial heterogeneity. At the small scale (10 m × 10 m), the values of the Shannon–Wiener and Pielou indices for fixed dunes were higher in the south than in the north. At the medium and large scales (20 m × 20 m and 50 m × 50 m, respectively), the index values were highest in the southwest, with generally greater values in the south than in the north. For semifixed and mobile dunes, the Shannon–Wiener and Pielou index values exhibited an east-high–west-low pattern at the 10 m × 10 m scale. This differentiation decreased with increasing scale, with the highest values observed in the northeast and southwest at the 50 m × 50 m scale. The spatial differentiation in functional diversity indices (Rao’s second-order entropy index and functional evenness index) exhibited distinct characteristics across the different dune types. (2) The spatial variation in all the diversity indices monotonically decreased with increasing scale, with the variance in the species diversity indices indicating the following order: Shannon–Wiener index > Pielou index > Simpson index. (3) The relationships between species richness and diversity indices exhibited significant scale dependence. At the small and medium scales, species richness was significantly positively correlated with the Shannon–Wiener index, Simpson index, and Rao’s quadratic entropy index and significantly negatively correlated with the Pielou evenness index and functional evenness index. However, at the large scale, none of these correlations were significant. (4) The species diversity indices and Rao’s quadratic entropy index were significantly positively correlated at the small and medium scales (p < 0.01), whereas a significant positive correlation with the functional evenness index was observed only at the 10 m × 10 m scale (p < 0.01). At the larger scale, these correlations became insignificant. In fixed dunes, areas of high Simpson index values exhibited a spatially complementary distribution with areas of high Shannon–Wiener index and Pielou index values, providing evidence for the combined effect of local processes such as competitive exclusion and dispersal limitation. Through comprehensive multiscale analysis, this study revealed the mechanisms underlying the scale-dependent relationships between plant species and functional diversity, thereby providing a theoretical basis for protecting and restoring desert biodiversity. Full article