The coupled effects of climate change and Land Use/Land Cover (LULC) change increasingly influence soil erosion. While numerous prior studies have examined these factors in isolation or within single regions, a thorough understanding of how erosion responses to LULC change vary across diverse climatic contexts is still lacking. This study addresses this gap by employing a globally comparative framework that combines the Revised Universal Soil Loss Equation (RUSLE) with six complementary statistical approaches, including fixed-effects panel regression, distributed lag analysis, class-specific dynamic models and Granger causality testing. Six major climatic zones throughout five countries (Brazil, China, the USA, India, and Australia) were examined from 2004 to 2023. The results revealed considerable variability in RUSLE-estimated erosion rates across different climate-region contexts. The relationships between LULC change and erosion differ substantially among climate zones, with agricultural expansion showing stronger positive associations in humid climates and weaker associations in arid regions. Forests exhibit variable protective effects depending on climatic conditions, with lagged associations persisting for up to eight years in some regions. Causality analysis further indicated that changes in forest cover can predict erosion dynamics in specific climate contexts, though this should be interpreted as predictive association rather than physical causation. Overall, our findings demonstrate that identical LULC transitions can produce markedly different erosion outcomes depending on climatic context, highlighting the need for climate-specific soil conservation strategies and the importance of integrating climate-land interactions into global land management frameworks.
Soil phosphorus (P) availability sustains nutrient supply, plant growth, and community persistence in alpine treeline ecosystems. Most studies emphasize spatial gradients, leaving within-season reorganization of individual P fractions and functional pools poorly resolved. We sampled 0–10 and 10–20 cm soils across three mountains and four vegetation belts in June, August, and October 2021 on the southeastern Qinghai-Tibet Plateau. Hedley fractionation separated six P fractions, which we grouped into Labile P, Moderately labile P, and Stable P. Fixed-effects models, partial η2, and sequential sums-of-squares shares compared monthly and spatial effects. The fractions changed asynchronously through the growing season. Labile P increased from June to October but retained stronger mountain and vegetation signals; Moderately labile P increased late in the growing season; and Stable P declined in October. The decline in Stable P was driven mainly by Residual P, even though HCl-P increased. The first two principal components explained 83.9% of the variation and separated samples mainly by month. Month had strong effects on Moderately labile P (partial η2 = 0.322) and Stable P (0.512), whereas mountain had a stronger effect on Labile P (0.141). Month SS shares were 73.2% for NaOH-Pi, 44.4% for NaOH-Po, 45.8% for Residual P, 27.7% for Moderately labile P, and 42.5% for Stable P, whereas mountain and vegetation effects were more pronounced for NaHCO₃-Po and Labile P. Month × vegetation significantly affected several fractions. Redundancy and relative-importance analyses further showed that the dominant soil correlates changed among months. These results reveal rapid within-season redistribution among alpine treeline ecotone soil P pools and show that temporal and spatial controls differ among fractions.
Climate warming is expected to alter dissolved organic matter (DOM) dynamics in peatlands, but responses remain unclear among peatland types and soil depths. We conducted a ground-warming field experiment in a Sphagnum-dominated fen (~ + 4.5 °C) and a Carex-dominated fen (~ + 3.8 °C) in northern Ontario, Canada. Results showed that warming significantly increased shallow porewater dissolved organic carbon (DOC), with a stronger effect in the Sphagnum fen (+59.8% vs. +12.5%). In the Sphagnum fen, warming increased shallow humification (HIX) and enriched medium- to high-aromatic humic-like components (C2, C3; especially C2) in both layers, indicating that warming preferentially converts fulvic-acid-like C1 into moderately humified DOM. In contrast, in the Carex fen, warming reduced soil moisture and aromaticity (SUVA254), increased deep BIX and fluorescence index (FI), and shifted components toward higher C2 and lower C3 in both layers, with fulvic-acid-like C1 increasing in shallow but decreasing in deep. These depth-specific shifts imply that drying interacts with warming to enhance oxidative degradation and microbial activities, producing less aromatic, more microbially influenced DOM, especially at depth. Structural equation modeling confirmed warming as the dominant driver in the Sphagnum fen, whereas in the Carex fen, warming acted synergistically with soil moisture and water table. Our results demonstrate that predicting the direction and magnitude of DOM quantity and quality changes under future warming requires considering warming magnitude, fen type, soil depth, and hydrological conditions.
Soil microbial interactions are crucial in maintaining ecosystem functions and the carbon (C) cycle. However, the regulatory mechanism of microbial cross-kingdom interactions on soil organic C (SOC) fractions remains unclear. Here, we collected soil samples along two independent elevation gradients in Zhongtiao Mountain (ZT) and Wutai Mountain (WT) in China. We used co-occurrence networks to investigate how cross-kingdom microbial interaction patterns are potentially linked to microbial metabolism and the distribution of particulate organic C (POC) and mineral-associated organic C (MAOC). We found that cross-kingdom interactions, particularly bacterial-fungal (competition) and protistan-bacterial (predation) networks, showed stronger associations with microbial metabolism than intra-kingdom interactions. Intensified cross-kingdom interactions were associated with reduced POC and MAOC by decreasing the microbial necromass accumulation coefficient (NAC) and increasing the microbial metabolic quotient (qCO2) in both mountains. Further analysis showed that cross-kingdom interactions were linked to clay content, with a decrease in clay content providing more favorable habitats for fungi and protists, potentially intensifying competition and predation among microorganisms. The decrease in clay content along elevations in the ZT and its increase in the WT corresponded to contrasting elevation distributions in microbial cross-kingdom interactions, microbial metabolism (NAC and qCO2), POC, and MAOC. Thus, these findings suggest a link between microbial community interactions and SOC, emphasizing that microbial cross-kingdom networks, which vary with soil texture and ecosystems, may play a key role in soil C dynamics through regulating microbial metabolism.
The middle–lower Yangtze River region hosts extensive aeolian deposits, among which the Poyang Lake sandy land (PYSL) constitutes a prominent and geomorphologically distinctive example. However, the relative contributions and synergistic interactions between aeolian and fluvial processes in shaping these landscapes remain insufficiently quantified, primarily due to methodological limitations and spatially fragmented research efforts. This knowledge gap impedes both robust paleoenvironmental reconstructions and the development of effective strategies for mitigating sand-related hazards. Here, an integrated provenance study of the PYSLs was conducted, combining detrital zircon UPb geochronology, heavy mineral analysis, and grain-size distribution. The multidimensional scaling (MDS) diagrams and inverse Monte Carlo models (IMCM) of detrital zircon ages indicate major provenance areas are the eastern Cathaysia Block (mainly the south and central Jiangxi ranges; 16.2–85.5%) and the Jiangnan Orogenic Belt (primarily the Jiuling Mountains; 14.5–83.8%). The results demonstrate pronounced spatial heterogeneity in sediment direct sources. The central PYSLs are primarily supplied by the Ganjiang and Xiushui rivers, whereas the northern PYSL is dominated by the Yangtze and Ganjiang rivers, and the southern PYSL derives sediment mainly from the Jinjiang river. Obviously, wind plays a subordinate role in large-scale sediment reworking, as evidenced by the marked compositional heterogeneity between the northern and southern PYSL. Nevertheless, aeolian processes remain dynamically active in the local redistribution of sediments within the central PYSLs. These findings collectively emphasize that topographic factors must be carefully considered in paleoenvironmental studies of aeolian deposits. However, surface samples provide only a limited view into longer-term landscape evolution.
