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| 1 | Simulating soil freezethaw cycles typical of winter alpine condi- tions: Implications for N and P availability显示文摘 | Michele Freppaz Berwyn L Williams Anthony C Edwards | 2007 | Applied Soil Eeol ogy2007，35，1： | 1 |
| 2 | Characterization of organic-rich mineral debris revealed by rapid glacier retreat, Indren Glacier, European Alps显示文摘In the summer of 2003 and 2004, characterized by a rapid glacier retreat, a stony surface covered by well-structured organic-rich mineral debris was observed very close to the Indren glacier terminus(Monte Rosa Massif, NW Italy, 3100 m ASL), on an area covered by the glacier tongue till the year before. The origin and type of this organicrich material were investigated, in order to detect their characteristics, potential sources and fate within the foreland system. The deposits were dated using Carbon-14 and analyzed for the chemical characteristics of the organic component, the elemental composition of the mineral fraction and presence of microbial markers. The material, granular and dark in color, had a total organic carbon(TOC) content ranging between 17.4 ± 0.39 and 28.1 ± 0.63 g kg^(-1) dry weight(dw), significantly higher than the surrounding glacial till(~ 1.4 g kg^(-1) dw), although only 0.33% of it was in water soluble form. Microbial carbon(C) and nitrogen(N) accounted for 10.6% and 3.13% of TOC and total N, respectively. Dissolved nitrogen(N), mainly present as ammonium, represented 2.40% of the total N. The low aromatic component and large presence of nitrogen(N)-derived compounds suggested that most of the organic carbon(OC) in these organic-rich mineral deposits was derived from microbial cells, although the high average radiocarbon age of about 2900 years may also point to the contribution of aeolian depositions of anthropogenic or natural origin. Elemental composition and the crustal enrichment factor of trace elements in the mineral fraction of the aggregates corroborated the hypothesis that most part of the accumulated material derived from ice meltwater. Some indicators of the colonization of these deposits by microbial communities were also reported, from the abundance of DNA and phylogenetic markers, to the presence of bacterial taxa commonly able to thrive in similar habitats. All these elements suggested that such kind of deposits may have a potential role as energy and nutrient sources in recently deglaciated areas, highlighting the necessity to better understand the processes underlying their formation and their evolution. | FREPPAZ Michele WILLIAMS Mark W. GABRIELI Jacopo GORRA Roberta MANIA Ilaria ASCHER-JENULL Judith EGLI Markus CELI Luisella | 2021 | Journal of Mountain Science2021，18，6： | 1 |
| 3 | Snow gliding and loading under two different forest stands: a case study in the north-western Italian Alps显示文摘The presence of a thick snowpack could interfere with forest stability, especially on steep slopes with potential damages for young and old stands.The study of snow gliding in forests is rather complex because this phenomenon could be influenced not only by forest features,but also by snow/soil interface characteristics, site morphology, meteorological conditions and snow physical properties.Our starting hypothesis is that different forest stands have an influence on the snowpack evolution and on the temperature and moisture at the snow/soil interface,which subsequently could affect snow gliding processes and snow forces.The aim of this work is therefore to analyse the snowpack evolution and snow gliding movements under different forest covers, in order to determine the snow forces acting on single trees.The study site is located in a subalpine forest in Aosta Valley(NW-Italy) and includes two plots at the same altitude, inclination and aspect but with different tree composition:Larch(Larix decidua) and Spruce(Picea abies).The plots were equipped with moisture and temperature sensors placed at the snow/soil interface and glide shoes for continuous monitoring of snow gliding.The recorded data were related to periodically monitored snowpack and snow/soil interface properties.Data were collected during two winter seasons(2009-10 and 2010-11).The snow forces on trees were analytically calculated either from snowpack data and site morphology or also from measured snow gliding rates.Different snow accumulations were observed under the two different forest stands, with a significant effect on temperature and moisture at the snow/soil interface.The highest snow gliding rates were observed under Larch and were related to rapid increases in moisture at the snow/soil interface.The calculated snow forces were generally lower than the threshold values reported for tree uprooting due to snow gliding, as confirmed by the absence of tree damages in the study areas. | Davide Viglietti Margherita Maggioni Enrico Bruno Ermanno Zanini Michele Freppaz | 2013 | Journal of Forestry Research2013，24，4： | 0 |
| 4 | Quantifying the contribution of the root system of alpine vegetation in the soil aggregate stability of moraine显示文摘One fifth of the world's population is living in mountains or in their surrounding areas.This anthropogenic pressure continues to grow with the increasing number of settlements,especially in areas connected to touristic activities,such as the Italian Alps.The process of soil formation on high mountains is particularly slow and these soils are particularly vulnerable to soil degradation.In alpine regions,extreme meteorological events are increasingly frequent due to climate change,speeding up the process of soil degradation and increasing the number of severe erosion processes,shallow landslides and debris flows.Vegetation cover plays a crucial role in the stabilization of mountain soils thereby reducing the risk of natural hazards effecting downslope areas.Soil aggregate stability is one of the main soil properties that can be linked to soil loss processes.Soils developed on moraines in recently deglaciated areas typically have low levels of soil aggregation,and a limited or discontinuous vegetation cover making them more susceptible to degradation.However,soil structure can be influenced by the root system of the vegetation.Roots are actively involved in the formation of water-stable soil aggregation,increasing the stability of the soil and its nutrient content.In the present study,we aim to quantify the effect of the root system of alpine vegetation on the soil aggregate stability of the forefield of the Lys glacier,in the Aosta Valley(NW-Italy).This proglacial area provides the opportunity to study how the root system of ten pioneer alpine species from different successional stages can contribute to soil development and soil stabilization.To quantify the aggregate stability of root permeated soils,a modified wet sieving method was employed.The root length per soil volume of the different species was also determined and later correlated with the aggregate stability results.The results showed that soil aggregate stability was significantly increased by the presence of roots.The lowest soil aggregate stability was found with Epilobium fleischeri followed by Minuartia recurva and Leucanthemopsis alpina.The highest aggregate stability was found with the graminoid species.These results show a close relationship between the development of root systems of the studied species and soil aggregate stability,a factor which can be taken into consideration in order to improve the accuracy of existing susceptibility mapping for early warning and civilian protection. | Csilla Hudek Silvia Stanchi Michele D’Amico Michele Freppaz | 2017 | International Soil and Water Conservation Research2017，5，1： | 0 |
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