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Water stored in weathered bedrock plays a crucial role in the terrestrial water cycle by influencing vegetation, streamflow, and groundwater recharge. Past studies on the impact of aspect‐driven differences in insolation quantify moisture in shallow soils but largely ignore moisture dynamics in deeper weathered bedrock. Here, we measure moisture dynamics via geophysical surveys and borehole measurements in two opposing hillslopes with similar properties in the seasonally dry central California Coast Range. Despite greater insolation, the grassy equator‐facing slope experienced less and shallower moisture withdrawal during the dry season relative to the pole‐facing slope with oak trees, which experienced greater and deeper moisture withdrawal. Consequently, following the dry season, water content on the grassy equator‐facing slope was higher, which may contribute to aspect‐dependent differences in runoff generation, landslide susceptibility, and drought resilience.

[This corrects the article DOI: 10.3389/fpls.2025.1562491.].

Background Wildfire and topography each have significant effects on soil biogeochemical cycles, but their interactive effects on soil nutrients remain largely unclear, hindering the precise prediction of the effects of fire on soil biogeochemical cycles in a larger spatial scale. Methods We examined soil nutrient contents from restored grass slopes that had suffered wildfires and adjacent restored grass slopes without any wildfire. Topographic factors included slope aspects (north and south slopes) and positions (upper, middle and lower slopes). Results Fire significantly increased the contents of soil organic carbon (OC), total nitrogen (TN) (0–10 cm), ammonium (NH4+), and extractable phosphorous (EP), decreased the contents of nitrate (NO3−) and available potassium (AK), and had minimum influence on total phosphorus (TP) content. Slope aspect and position also affected soil nutrients, with higher contents in the north slope than the south slope and at the upper slope than the lower slope. The effects of fire on soil OC, TN, and NO3− were consistent across north and south slopes, but the effects on soil NH4+, TP, EP and AK varied with slope aspect. However, the effects of fire on soil nutrients were not influenced by slope position. Conclusion These results indicate that slope aspect should be considered in predicting the response of soil biogeochemical cycles to fire.

Topography-induced microclimate differences determine the local spatial variation of soil characteristics as topographic factors may play the most essential role in changing the climatic pattern. The aim of this study was to investigate the spatial distribution of soil organic carbon (SOC) with respect to the slope gradient and aspect, and to quantify their influence on SOC within different land use/cover classes. The study area is the Region of Niš in Serbia, which is characterized by complex topography with large variability in the spatial distribution of SOC. Soil samples at 0–30 cm and 30–60 cm were collected from different slope gradients and aspects in each of the three land use/cover classes. The results showed that the slope aspect significantly influenced the spatial distribution of SOC in the forest and vineyard soils, where N- and NW-facing soils had the highest level of organic carbon in the topsoil. There were no similar patterns in the uncultivated land. No significant differences were found in the subsoil. Organic carbon content was higher in the topsoil, regardless of the slope of the terrain. The mean SOC content in forest land decreased with increasing slope, but the difference was not statistically significant. In vineyards and uncultivated land, the SOC content was not predominantly determined by the slope gradient. No significant variations across slope gradients were found for all observed soil properties, except for available phosphorus and potassium. A positive correlation was observed between SOC and total nitrogen, clay, silt, and available phosphorus and potassium, while a negative correlation with coarse sand was detected. The slope aspect in relation to different land use/cover classes could provide an important reference for land management strategies in light of sustainable development.

Aim: In the alpine life zone, plant diversity is strongly determined by local topography and microclimate. We assessed the extent to which aspect and its relatedness to temperature affect plant species diversity, and the colonization and disappearance of species on alpine summits on a pan-European scale. Location: Mountain summits in Europe's alpine life zone. Methods: Vascular plant species and their percentage cover were recorded in permanent plots in each cardinal direction on 123 summits in 32 regions across Europe. For a subset from 17 regions, resurvey data and 6-year soil temperature series were available. Differences in temperature sum and Shannon index as well as species richness, colonization and disappearance of species among cardinal directions were analysed using linear mixed-effects and generalised mixed-effects models, respectively. Results: Temperature sums were higher in east-and south-facing aspects than in the north-facing ones, while the west-facing ones were intermediate; differences were smallest in northern Europe. The patterns of temperature sums among aspects were consistent among years. In temperate regions, thermal differences were reflected by plant diversity, whereas this relationship was weaker or absent on Mediterranean and boreal mountains. Colonization of species was positively related to temperature on Mediterranean and temperate mountains, whereas disappearance of species was not related to temperature. Main conclusions: Thermal differences caused by solar radiation determine plant species diversity on temperate mountains. Advantages for plants on eastern slopes may result from the combined effects of a longer diurnal period of radiation due to convection cloud effects in the afternoon and the sheltered position against the prevailing westerly winds. In northern Europe, long summer days and low sun angles can even out differences among aspects. On Mediterranean summits, summer drought may limit species numbers on the warmer slopes. Warmer aspects support a higher number of colonization events. Hence, aspect can be a principal determinant of the pace of climate-induced migration processes.

Background and aims Altitude, season, and slope aspect have significant impacts on bacterial variation in forest soils. However, it is currently unclear which factor has the greatest influence. Methods Quantitative PCR (qPCR) and high-throughput sequencing were employed to investigate the changes in the bacterial communities with altitude, season and slope aspect in the subtropical forests of Mount Ailao. Results The effects of altitude, season and slope on bacterial abudance were in the order altitude (η 2  = 0.964) > season (η 2  = 0.831) > slope (η 2  = 0.590). In addition, the bacterial abundance increased with altitude, and the rainy season but not the dry season, the eastern slope rather than the western slope had a higher bacterial abundance. Furthermore, altitude (η 2 : 0.877–0.942) and season (η 2 : 0.229–0.761), resulted in higher bacterial α-diversity at low altitudes and in the dry season, respectively. Synergistetes/Verrucomicrobia (low altitude), Acidobacterium (high altitude), Actinobacteria/Planctomycetes (dry season) and Armatipnoadetes (rainy season) were the richest in the soils. Correlation networks showed that bacteria were very stable at higher altitudes and in the dry season. In addition, soil water content, soil organic matter, total nitrogen and ammonium nitrogen were the key edaphic factors significantly affecting the bacterial abundance, α-diversity, and β-diversity. Conclusions Altitudes rather than seasons and slope aspects had the greatest effect on the bacterial communities in subtropical forests. Therefore, we suggest that altitude, season, and slope aspect be considered necessary factors for comprehensive analysis when studying soil microbial changes in different forests. Graphical abstract

Dolines are small- to large-sized bowl-shaped depressions of karst surfaces. They may constitute important microrefugia, as thermal inversion often maintains cooler conditions within them. This study aimed to identify the effects of large- (macroclimate) and small-scale (slope aspect and vegetation type) environmental factors on cool-adapted plants in karst dolines of East-Central Europe. We also evaluated the potential of these dolines to be microrefugia that mitigate the effects of climate change on cool-adapted plants in both forest and grassland ecosystems. We compared surveys of plant species composition that were made between 2007 and 2015 in 21 dolines distributed across four mountain ranges (sites) in Hungary and Romania. We examined the effects of environmental factors on the distribution and number of cool-adapted plants on three scales: (1) regional (all sites); (2) within sites and; (3) within dolines. Generalized linear models and non-parametric tests were used for the analyses. Macroclimate, vegetation type and aspect were all significant predictors of the diversity of cool-adapted plants. More cool-adapted plants were recorded in the coolest site, with only few found in the warmest site. At the warmest site, the distribution of cool-adapted plants was restricted to the deepest parts of dolines. Within sites of intermediate temperature and humidity, the effect of vegetation type and aspect on the diversity of cool-adapted plants was often significant, with more taxa being found in grasslands (versus forests) and on north-facing slopes (versus south-facing slopes). There is large variation in the number and spatial distribution of cool-adapted plants in karst dolines, which is related to large- and small-scale environmental factors. Both macro- and microrefugia are therefore likely to play important roles in facilitating the persistence of cool-adapted plants under global warming.

Understanding the effect of aspect on landform characteristics and erosion rates is an important prerequisite for soil and water conservation in hilly areas. In a cultivated area of the Chinese Loess Plateau, hillslope length, gradient and aspect (east, west, south, and north) were measured on two typical Mao (round loess hill), and net soil loss and location (upper, middle and lower positions) were studied using the 137 Cs tracing loss ratio. Hillslope length on different aspects was in the order, north > west > east >south, but gradient changes were inconsistent and more complicated. Southern slopes were shorter and steeper, while on northern slopes, it was the opposite. Erosion rate on hillslopes with different aspects ranged from 1440 to 2631 t/km 2 · a, and on northern slopes they were c.24–81% larger than on southern slopes. Upper and middle hillslope positions usually had higher erosion rates than lower positions. The greatest erosion rates were at upper positions on northern slopes, and upper positions on south slopes had relatively lower erosion rates. For hillslope positions influenced by wind erosion in winter and spring, the 137 Cs loss ratio could be > 80%, while for the same positions on south slopes without wind erosion, it was < 80%. Our findings demonstrate that aspect is a key driver of landform characteristics and erosion rates on hillslopes, and they could be usefully employed for the prevention and control of soil erosion in this region.

The Newmark displacement (ND) method, which reproduces the interactions between waves, solids, and fluids during an earthquake, has experienced numerous modifications. We compare the performances of a traditional and a modified version of the ND method through the analysis of co-seismic landslides triggered by the 2022 Ms 6.8 Luding earthquake (Sichuan, China). We implemented 23 ND scenarios with each equation, assuming different landslide depths, as well as various soil-rock geomechanical properties derived from previous studies in regions of similar lithology. These scenarios allowed verifying the presence or absence of such landslides and predict the likely occurrence locations. We evaluated the topographic and slope aspect amplification effects on both equations. The oldest equation has a better landslide predictive ability, as it considers both slope stability and earthquake intensity. Contrarily, the newer version of the ND method has a greater emphasis on slope stability compared to the earthquake intensity and hence tends to give high ND values only when the critical acceleration is weak. The topographic amplification does not improve the predictive capacity of these equations, most likely because few or no massive landslides were triggered from mountain peaks. This approach allows structural, focal mechanism, and site effects to be considered when designing ND models, which could help to explain and predict new landslide distribution patterns such as the abundance of landslides on the NE, E, S, and SE-facing slopes observed in the Luding case.

The formation of avalanche hazards in mountainous regions is largely influenced by slope insolation and albedo. This paper presents a quantitative analysis of how solar radiation, surface reflectivity (albedo), temperature, and snow cover affect avalanche formation depending on slope aspect (north-, south-, east-, and west-facing). This study is based on remote sensing data from MODIS, ERA5-Land, CHIRPS, and a digital terrain model for the winter periods from 2000 to 2024. The results show that north-facing slopes have higher albedo values (up to 0.95) and greater snow cover stability (30–50%), which contributes to increased avalanche risk, especially at temperatures above −5 °C. South-facing slopes are characterized by lower albedo values (around 0.20–0.40) and more intense snowmelt, which reduces the likelihood of avalanches. Regression analysis revealed a strong positive correlation between snow depth and avalanche risk (r = 0.87), as well as a moderate negative correlation between temperature and snow cover stability (r = −0.25). The influence of albedo on avalanche risk was found to be indirect, acting through its impact on the surface energy balance. The resulting avalanche risk map demonstrated high accuracy (overall agreement: 86%; Kappa coefficient: 0.72), highlighting the effectiveness of an integrated approach based on geophysical and climatic parameters. The data obtained can be used to support avalanche safety management and slope assessment in the context of climate change.