Introduction: Microbial communities and their associated carbon, nitrogen, and phosphorus metabolic processes play a role in maintaining ecological functions and nutrient cycling in riparian zones. However, systematic research on the coupling mechanisms of carbon, nitrogen, and phosphorus biogeochemical processes in soil profiles of semi-arid riparian soil is still limited. Methods: This study focused on the riparian zone of the Tuwei River, a typical semi-arid river. Metagenomic sequencing was used to analyze the composition of microbial communities and their carbon, nitrogen, and phosphorus metabolic functions across different soil depths along the river. Results: The dominant taxa across all depths and river sections were Proteobacteria (average relative abundance 49.85%) and Serratia (11.23%). Results from ANOVA and Tukey–Kramer post-hoc multiple comparison tests showed that microbial diversity significantly decreased with increasing soil depth ( p < 0.05). Gene families associated with carbon fixation ( accC, pccB ), denitrification ( nosZ, nirK ), and phosphorus metabolism ( purC, guaB, pyrG ) were significantly enriched in surface soils and showed clear depth-dependent declines ( p < 0.05). Partial Mantel tests revealed that microbial metabolic functions were significantly correlated with porosity ( p < 0.05), soil organic carbon, total nitrogen, and total phosphorus, confirming that nutrient availability and soil structure are key regulators of microbial biogeochemical functions. Conclusion: Our findings reveal that nutrient availability and soil structure jointly regulate the vertical distribution of microbial metabolic functions. These insights provide a scientific basis for ecological restoration and soil management in semi-arid riparian zones, where optimizing surface structure and nutrient inputs can stimulate microbial-driven biogeochemical cycling. Key functional taxa and genes may also serve as sensitive indicators for evaluating restoration effectiveness under climate-induced stress.

Landscapes in semiarid regions are highly sensitive to climate change and anthropogenic activities, and their evolution directly influences ecosystem services and regional ecological security. Although previous research has examined land use changes, systematic quantitative analyses of long-term evolutionary trends and driving mechanisms, particularly the comprehensive relationships between key hydrological elements and landscape pattern evolution in water-scarce, semiarid watersheds, remain limited. To address the research gap in long-term, multifactor, and hydro–landscape integrated analysis, China’s Tuwei River watershed was selected as the study area in this study, and methods such as landscape pattern indices and gray relational analysis were employed to quantitatively reveal the spatiotemporal evolution of watershed landscape fragmentation from 1980 to 2020 and identify its dominant driving forces. The results revealed that (1) over the 40-year period, the land use structure of the watershed underwent significant restructuring, with developed land expanding by 1282%, cropland and bare land areas decreasing by 14.2% and 32.01%, respectively, and grassland and forestland areas increasing by 24.5% and 14.9%, respectively; (2) land-scape fragmentation continued to intensify, with the landscape fragmentation composite index (FCI) increasing by 37.6%, patch density (PD) continuously increasing, edge density (ED) and landscape shape index (LSI) increasing significantly, and landscape connectivity weakening; (3) natural and socioeconomic factors jointly drove landscape evolution, with temperature and mean annual flow contributing the most among natural factors and the urbanization rate and secondary industry output value serving as the core drivers among socioeconomic factors; and (4) the trend of landscape fragmentation was synchronized with changes in annual rainfall and runoff and exhibited a significant negative correlation with the groundwater level. In summary, through long-term, multifactor comprehensive analysis, the evolution characteristics and driving mechanisms of landscape patterns in the Tuwei River watershed were systematically revealed in this study. These findings not only deepen the understanding of landscape fragmentation processes under the dual pressures of climate change and anthropogenic activities but also provide scientific evidence for the sustainable management of landscapes and associated ecosystems in semiarid watersheds.

As a critical aquatic–terrestrial ecological transition zone, the lake littoral zone exhibits steep biogeochemical gradients and plays a vital role in regulating submerged microbial communities and their functions. This study aims to reveal how multi-scale environmental gradients influence microbial succession processes along desert lake littoral zones, as well as the distribution patterns of functional genes involved in carbon (C), nitrogen (N), and sulfur (S) cycling. The results demonstrated that microbial alpha-diversity in the vadose zone exhibited significant individual variability horizontally, while showing pronounced inter-group differences vertically. Horizontally, a distinct functional succession was observed from the shore to the water’s edge, with microbial potential shifting progressively from aerobic oxidative types toward anaerobic reductive types. Vertically, the root-intensive layer fostered more complex co-occurrence networks through enhanced interspecific interactions, suggesting higher functional resilience compared to other layers. Further analysis identified soil moisture as the primary environmental filter driving microbial composition, explaining 27.7% of the variation. Structural equation modeling (SEM) further elucidated that pH and Total Organic Carbon (TOC) were the key regulators of carbon fixation and sulfur oxidation genes, while Total Nitrogen (TN) dominated the distribution patterns of nitrogen cycling genes. These findings deepen the mechanistic understanding of microbial-mediated element cycling in desert lakeshore zones and provide a theoretical basis and data support for maintaining the functions of these fragile ecosystems.

In arid inland watersheds, the compounding impacts of climate change and intensive human activities have severely altered hydrological regimes and accelerated landscape degradation. However, conventional spatial planning often overlooks the critical coupling between subsurface hydrological processes and surface landscape dynamics. Taking the Manas River Watershed in northwestern China as a representative case, this research investigates the multi-scale dynamics of landscape patterns and their underlying spatial determinants. Integrating multi-period land-use data (2000–2020), landscape metrics, and the GeoDetector model, we diverge from conventional uniform buffer approaches by redefining riparian boundaries utilizing four distinct River–Groundwater Transformation (RGT) patterns. This methodological shift reveals critical eco-hydrological heterogeneities previously masked by fixed-width approaches. Our multi-scale analyses demonstrate that watershed-level landscapes exhibited a trajectory of declining diversity, transient recovery, and ultimately, intensified fragmentation, while riparian patches concurrently expanded and became increasingly homogenized. GeoDetector assessments indicate a fundamental shift in driving forces: early-stage variations were constrained by natural factors, whereas post-2010 dynamics became overwhelmingly dominated by socio-economic determinants, particularly agricultural expansion and GDP growth. Crucially, our RGT-coupled spatial analysis reveals a strong spatial association between agricultural sprawl and landscape risk hotspots concentrated within groundwater overflow zones—a pattern consistent with, but not directly demonstrating, disrupted vertical hydrological connectivity. Direct verification of subsurface mechanisms would require continuous piezometric monitoring beyond the scope of this study. Consequently, rather than generic zoning, we propose a multi-scale “hydro-spatial” governance framework featuring targeted interventions. By establishing strict agricultural redlines in vulnerable overflow zones and implementing eco-hydrological restoration tailored to specific RGT regimes, this paradigm delivers robust methodological insights for advancing precision spatial planning in fragile arid ecosystems.