Search Results (8)

Soil salinization threatens agricultural sustainability in arid zones, yet quantitative attribution of its spatiotemporal dynamics to multi-source drivers remains scarce at regional scales. To address this, we developed an explainable framework merging Sentinel-1/2, ERA5-Land, and topographic-hydrological indices with XGBoost, trained under weak supervision with proxy labels and independently validated using field-measured ECe. A 7-group, 44-feature ensemble with spatial block 5-fold cross-validation ensured robust assessment. SHapley Additive exPlanations (SHAP) quantified driver contributions and enabled a novel dominant driver zoning (DDZ) framework. Monitoring the Hexi Corridor and Tarim Basin (2017–2024) revealed contrasting trajectories: Hexi’s dynamics were primarily climate-driven (Aridity Index), whereas 19.2% of Tarim showed significant salinization along oasis–desert margins co-dominated by elevation, soil indices, and temperature. The model achieved spatial cross-validation R² values around 0.65. DDZ mapping showed climate dominance in 98.2% of Hexi compared to 76.5% in Tarim, where terrain and optical factors were more influential. The weak supervision strategy overcomes scarce in-situ measurements, while the DDZ maps identified that Land-use-dominated zones recorded the highest salinity, offering clear directives for targeted salinity control in arid basins. Full article

Rural black-odorous waterbodies (RBOWBs) represent a critical environmental challenge in China, yet the vertical stratification of sedimentary bacterial communities and its underlying drivers remain poorly understood. This study combined 16S rRNA gene amplicon sequencing across five sediment depths (0–125 cm) with shotgun metagenomic analysis of surface sediments to investigate bacterial diversity, composition, and functional potential in typical rural black-odorous systems of Dongming County, Shandong Province. Results showed a clear decline in bacterial richness with increasing sediment depth, with the surface layer (0–25 cm) exhibiting 1.2–1.9 times higher diversity than deeper strata. Community composition displayed distinct vertical zonation: Chloroflexi and Thiobacillus dominated surface layers and were linked to carbon hydrolysis and desulfurization, whereas Bacillus and nitrifying bacteria prevailed in deeper anoxic layers. Metagenomic analysis revealed high genetic potential for carbohydrate metabolism, amino acid biosynthesis, and sulfur-nitrogen cycling, with glycoside hydrolases (GHs) and glycosyl transferases (GTs) being particularly abundant. Statistical correlations identified total phosphorus (TP₁), dissolved oxygen (DO), and pH of the overlying water—rather than sediment intrinsic nutrients—as the primary environmental factors associated with microbial functional stratification. These findings provide a mechanistic understanding of vertical microbial zonation in rural black-odorous sediment and offer a microbiological basis for developing depth-resolved sustainable remediation strategies. Full article

Despite the ecological sensitivity of the Yangtze River Source Region (YRSR), the current research critically lacks a quantified assessment of the spatial occurrence probability of Retrogressive Thaw Slumps (RTSs) in this specific high-altitude terrain. This study aims to bridge this knowledge gap by establishing a robust susceptibility assessment framework to accurately model the spatial distribution and risk levels of RTSs. The innovations of this research include (i) the construction of a complete and up-to-date 2024 RTS inventory for the entire YRSR based on high-resolution optical remote sensing; (ii) the integration of time-series spectral features (e.g., vegetation and moisture trends) alongside static topographic variables to enhance the physical interpretability of machine learning models; and (iii) the application of advanced ensemble learning algorithms combined with SHAP analysis to establish a comprehensive RTS susceptibility zonation. The results reveal a rapid intensification of instability, evidenced by an 83.5% surge in RTS abundance, with the CatBoost model achieving exceptional accuracy (AUC = 0.994), and identifying that specific static topographic factors (particularly elevations between 4693 and 4812 m and north-to-east aspect) and dynamic spectral anomalies (indicated by declining vegetation vigor and increasing surface wetness) are the dominant drivers controlling RTS distribution. This study provides essential baseline data and spatial guidance for ecological conservation and engineering maintenance in the Asian Water Tower, demonstrating a highly effective paradigm for monitoring permafrost hazards under climate warming. Full article

This study investigated the structure of vegetation communities in Yongneup, a representative montane peatland on Mt. Daeamsan, Korea. It also identified key microenvironmental drivers shaping their distribution. We surveyed 200 quadrats, analyzing herbaceous plant composition alongside peat depth, water level, and soil chemical properties. Multivariate analyses, including cluster analysis and classification tree analysis (CHAID), identified nine distinct vegetation communities. Each community was correlated with specific environmental gradients. Dominant species included Sanguisorba tenuifolia and Carex thunbergii var. appendiculata, with rare species such as Carex chordorrhiza and Drosera rotundifolia present in localized habitats. Peat depth emerged as the primary determinant of vegetation distribution, followed by hydrology and nutrient levels, including phosphorus and cations (Mg²⁺, Na⁺, K⁺). Our results underscored continuous ecological gradients rather than discrete zonation, aligning with ecological continuum theory. These findings provide a robust scientific framework for ecological monitoring and restoration. They also support Korea’s national wetland conservation policies and international commitments such as the Ramsar Convention. Full article

Bumblebees are among the most important wild pollinators; however, their populations are declining worldwide due to factors such as climate change, habitat loss, and pesticide use. For their conservation, it is important to understand the community structure at the local scale and the drivers responsible for their assemblages. However, little is known about bumblebee community assemblages and their drivers in Yunnan Province, China. In this study, we mapped bumblebee community assemblages across 125 counties in Yunnan Province using field-collected and published data. We also quantified the climatic and land use/land cover (LULC) drivers shaping these assemblages. The climatic habitat suitability for 21 bumblebee species was assessed at the county level across Yunnan using species distribution modeling. The biogeographic zones (groups of counties) were identified using Ward’s agglomerative cluster analysis, and the impacts of 12 bioclimatic and LULC drivers on the zonation pattern were assessed using Canonical Correspondence Analysis (CCA). Results indicated that more than 70% of bumblebee species showed their highest environmental suitability in the northern region of Yunnan. Among climatic factors, temperature-related bioclimatic variables were identified as dominant drivers influencing the spatial distribution of 15 out of 21 bumblebee species within the counties of Yunnan. In contrast, five species, B. grahami, B. impetuosus, B. lepidus, B. picipies, and B. securus, showed the highest contribution from precipitation-related factors. Six biogeographic zones (I, II, III, IV, V, and VI) were identified using Ward’s agglomerative cluster analysis. All 12 drivers were found to play critical roles in shaping the community assemblages of bumblebee species. This study provides essential insights for devising targeted conservation strategies at a local scale to maintain bumblebee populations in Yunnan. Full article

The Hengduan Mountains, a global biodiversity hotspot, harbor numerous endemic plant species shaped by complex topography and microclimatic variation. However, increasing habitat fragmentation due to human activities threatens narrowly distributed species such as Cycas panzhihuaensis. To investigate its habitat suitability and inform conservation, we applied the MaxEnt model, Geodetector, and Zonation to predict potential distribution, identify key environmental drivers, and delineate priority conservation areas. Our results show that only 18.36% of the region constitutes suitable and highly fragmented habitat, primarily concentrated along the dry–hot valleys of the Jinsha and Yalong Rivers, and it is shrinking while shifting southward and southeastward under climate change. Elevation emerged as the dominant driver (q = 0.45), with strong interaction effects among topographic, climatic, soil, and anthropogenic factors, highlighting the role of environmental synergies in shaping habitat heterogeneity. Priority conservation areas covered 32% of suitable habitat and overlapped only 6.17% with existing protected areas, indicating a spatial conservation gap. These findings emphasize the need to incorporate microhabitat heterogeneity and environmental interactions in conservation planning and support the adoption of micro-reserve strategies to complement existing reserves. Our study provides a practical framework for protecting vulnerable montane species and offers insights into plant distribution dynamics in topographically complex regions. Full article

Understanding how elevation influences forest structure and species composition is crucial for effective conservation in mountainous regions like Nepal, where ecosystems change dramatically over short distances. This study assessed forest dynamics along an elevational gradient (600–3200 m) in Nepal’s mid-hills, incorporating elevational zonation (Tropical, Subtropical, Lower Temperate, and Upper Temperate) and aspect-driven variations. We established 27 square plots (20 × 20 m) at 100 m elevation intervals along a trekking route from Tallo Dungeshwor near the Karnali River to Mahabu Lek, recording all tree species with a diameter at breast height (DBH) ≥ 5 cm. Tree density across the elevational gradient ranged from 250 to 800 trees/ha. Basal area varied between 7.46 and 82.43 m²/ha, while mean tree height ranged from 6.89 to 16.62 m. Species diversity was assessed using the Shannon diversity index, and species dominance was evaluated through the Importance Value Index (IVI). Diversity peaked at mid-elevations, with Shorea robusta and Quercus semicarpifolia identified as dominant species. While minor variations occurred across topographic aspects, statistical analysis confirmed elevation as the dominant driver of forest structure and composition. Correlation analysis revealed a significant positive relationship between elevation and Simpson’s diversity index (r = 0.45, p < 0.05), indicating increased dominance diversity at higher elevations. These findings highlight the critical role of elevation and aspect in shaping forest ecosystems and offer valuable baseline data for climate-resilient management. We recommend conservation planning that is sensitive to topographic gradients, integrates long-term, climate-adaptive monitoring, and engages local communities to anticipate ecological shifts and address mounting anthropogenic pressures in vulnerable montane zones. Full article

The Siberian Arctic Shelf is an area of increasing anthropogenic activity and is predicted to be significantly impacted by climate change. Accordingly, there is an increased demand for baseline knowledge on the scales of natural spatiotemporal variation of different ecosystem components. The study aimed to investigate the spatial variability of macrobenthic communities and associated abiotic forcing in the Ob Bay, a major Arctic estuary. Four main zones of macrobenthic communities were identified: a brackish-water zone in the upper part of the estuary, which was divided into two subzones according to the dominant species; a transition zone at the mouth of the Ob Bay; and a marine zone. This zonation remained stable during the study period (2013–2019) and corresponded well with previous studies in the area. The large-scale variation in macrobenthic communities was related mainly to two independent drivers: salinity and sediment type. The within-zone variation increased with the number of coexisting species, but no temporal trends could be assessed. The study highlights the need to account for the small-scale heterogeneity of benthic communities to understand ecosystem functioning and long-term dynamics, particularly in areas where environmental conditions vary markedly. Full article