We studied the effects of three soil management approaches (permanent grassing, chemical weeding, and buffer strips), and the additional impact of tractor passage on soil erosion in a sloping vineyard located in the inner part of Aosta Valley (N-W Italian Alps). The vineyard rows were equipped with a sediment collection system with channels and barrel tanks. A total of 12 events with sediment production were observed across 6 years, and the collected sediments were weighted and analyzed. Average erosion rates ranged from negligible (mainly in grassed rows) to 1.1 t ha⁻¹ per event (after weeding). The most erosive event occurred in July 2015, with a total rainfall of 32.2 mm, of which 20.1 were recorded in 1 h. Despite the limited number of erosive events observed, and the low measured erosion rates, permanent grassing reduced soil erosion considerably with respect to weeding; buffering had a comparable effect to grassing. The tractor passage, independent of the soil management approaches adopted, visibly accelerated the erosion process. The collected sediments were highly enriched in organic C, total N, and fine size fractions, indicating a potential loss of fertility over time. Despite the measured erosion rates being low over the experiment’s duration, more severe events are well documented in the recent past, and the number of intense storms is likely to increase due to climate change. Thus, the potential effects of erosion in the medium and long term need to be limited to a minimum rate of soil loss. Our experiment helped to compare soil losses by erosion under different soil management practices, including permanent grassing, i.e., a nature-based erosion mitigation measure. The results of the research can provide useful indications for planners and practitioners in similar regions, for sustainable, cross-sectoral soil management, and the enhancement of soil ecosystem services.

The skiing industry often represent the main contribution to mountain regions’ economy, by providing several economic benefits and the improvement of services and infrastructure. Ski resorts also play a crucial role as an impacting factor, causing severe changes on Alpine landscape and ecosystems. In particular ski runs construction and operation have considerable impacts on alpine soils, influencing their chemical and physical properties which affecting the establishment and development of plant communities. The work provides a description of the changes in soil properties and the related effects on vegetation. It aims furthermore to investigate the recent best practices applied for a successful soil restoration after ski runs construction, which may contribute to a sustainable use of mountain soils and ecosystems. Based on the current regulatory framework, this review gives a global overview on how, in Europe and specifically in Italy, the sustainable use of soils is considered during the construction and management of ski runs. As the framework is still lacking of specific rules regarding soil protection and management on ski runs, the present work wishes to provide recommendations in order to fill this gap, favoring the effective application of best practices for soil protection during ski run construction and maintenance.

The snowbed habitats represent a relevant component of the alpine tundra biome, developing in areas characterized by a long-lasting snow cover. Such areas are particularly sensitive to climate changes, because small variations in air temperature, rain, and snowfall may considerably affect the pedoclimate and plant phenology, which control the soil C and N cycling. Therefore, it is fundamental to identify the most sensitive abiotic and biotic variables affecting soil nutrient cycling. This work was performed at seven permanent snowbed sites belonging to Salicetum herbaceae vegetation community in the northwestern Italian Alps, at elevations between 2,686 and 2,840 m.a.s.l. During a four-year study, we investigated climate, pedoclimate, floristic composition, phenology, and soil C and N dynamics. We found that lower soil water content and earlier melt-out day decreased soil N-NH₄⁺, N-NO₃⁻, dissolved organic carbon (DOC), dissolved organic nitrogen (DON), total dissolved nitrogen (TDN), microbial nitrogen (Nmicr), microbial carbon (Cmicr), and C:Nmicr ratio. The progression of the phenological stages of Salix herbacea reduced soil N-NH₄⁺ and increased DOC. Our results showed that the snow melt-out day, soil temperature, soil water content, and plant phenological stages were the most important factors affecting soil biogeochemical cycles, and they should be taken into account when assessing the effects of climate change in alpine tundra ecosystems, in the framework of long-term ecological research.

Mountain regions are vulnerable to climate change but information about the climate sensitivity of seasonally snow-covered, subalpine ecosystems is still lacking. We investigated the impact of climatic conditions and pedogenesis on the C and N cycling along an elevation gradient under a Larch forest in the northwest (NW) Italian Alps. The environmental gradient that occurs over short distances makes elevation a good proxy for understanding the response of forest soils and nutrient cycling to different climatic conditions. Subalpine forests are located in a sensitive elevation range—the prospected changes in winter precipitation (i.e., shift of snowfalls to higher altitude, reduction of snow cover duration, etc.) could determine strong effects on soil nitrogen and carbon cycling. The work was performed in the western Italian Alps (Long-Term Ecological Research- LTER site Mont Mars, Fontainemore, Aosta Valley Region). Three sites, characterized by similar bedrock lithology and predominance of Larix decidua Mill., were selected along an elevation gradient (1550–1900 m above sea level-a.s.l.). To investigate the effects on soil properties and soil solution C and N forms of changing abiotic factors (e.g., snow cover duration, number of soil freeze/thaw cycles, intensity and duration of soil freezing, etc.) along the elevation gradient, soil profiles were opened in each site and topsoils and soil solutions were periodically collected from 2015 to 2016. The results indicated that the coldest and highest soil (well-developed Podzol) showed the highest content of extractable C and N forms (N-NH₄⁺, DON, DOC, C_micr) compared to lower-elevation Cambisols. The soil solution C and N forms (except N-NO₃⁻) did not show significant differences among the sites. Independently from elevation, the duration of soil freezing, soil volumetric water content, and snow cover duration (in order of importance) were the main abiotic factors driving soil C and N forms, revealing how little changes in these parameters could considerably influence C and N cycling under this subalpine forest stand.

Permafrost is warming and thawing due to climate change. Among the related effects, water quality modification has gained increasing attention globally. Nevertheless, the impacts of diffuse permafrost thaw on water chemistry in high-mountain areas remain largely unexplored. Here, we investigated the seasonal and interannual variability of water chemistry of two close-by ponds located in high-elevation catchments (European Alps, NW Italy) with and without permafrost. We analyzed major ions and stable water isotopes (2014–2022; weekly to monthly sampling during the ice-free season) and leveraged ground thermal measurements in a 30-m deep borehole. We also used geochemical modeling to investigate the impacts of permafrost thaw on dominant weathering processes. Despite similar climatic conditions, lithological characteristics, and water sources contribution, we observed higher concentrations and more pronounced seasonal increases of most solutes in the pond located within the permafrost catchment compared to the pond in the permafrost-free catchment. This was particularly evident for sulfate, with mean concentrations approximately four times higher in the permafrost pond. In the permafrost catchment, progressive warming and thawing during the investigation period enhanced sulfide oxidation, likely due to increased exposure of unweathered, sulfide-bearing rock particles. However, enhanced weathering did not lead to acidification and water quality deterioration due to pH buffering capacity provided by dissolving silicates and carbonates. Global warming is expected to further accelerate permafrost thawing and related chemical weathering in transitional permafrost areas. Water quality issues may arise in catchments with poor acid neutralizing potential of rocks.

Alpine tundra ecosystems are highly sensitive to climate change, particularly due to their dependence on the duration and timing of snow cover. This study investigated the effects of the climate extreme years 2022 and 2023 on carbon (C) and nitrogen (N) forms in two alpine tundra communities: snowbed (SB) and Carex curvula (CC), located at high elevation in the North-West (NW) Italian Alps. During these years, both sites experienced exceptionally low snow cover duration and elevated mean soil temperature during the snow-free season. Dissolved organic carbon (DOC) concentrations significantly increased by +65% in SB and +42% in CC compared to 2016–2021, likely reflecting enhanced microbial decomposition of organic matter. In contrast, soil ammonium and nitrate levels showed no significant changes, indicating differential responses between C and N processes. These findings suggest that DOC is a sensitive (early) indicator of climate-induced shifts in soil functioning. Given the critical role of alpine tundra in global C cycling, understanding DOC dynamics under climate extreme events is crucial to predict future ecosystem feedback to global change.