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Early stages of the serpentine syndrome in the Alps : results from a proglacial area
No full textGlacial retreat since the end of the Little Ice Age (LIA, 190-160 years ago) caused the exposure of “new” surfaces, over which ecosystems and soils develop following different pathways associated to different lithology.
The Verra Grande glacier forefield has a serpentinitic lithology, with small gneiss amounts in eastern sectors. We sampled soils and surveyed vegetation in 55 sites, in order to observe the pedogenic trends and the associated plant-soil relationships, and characterize the early stages of serpentine syndrome in subalpine, mid-latitude environments.
The soils developed slowly, with only minor organic matter accumulation and acidification, and increase in exchangeable Ni in 190 years. No trends in the Ca/Mg ratio nor in available P were measured. The difference was striking when compared with nearby glacier forefields on gneiss, where podzolization was ongoing in LIA soils. Where minor amounts of gneiss were present, a slightly faster pedogenesis occurred, associated with a stronger nutrient bioaccumulation.
As a consequence, the terrain remained almost barren for more than 190 years since moraine deposition on pure serpentinite, while higher P and lower Ni availability were associated with a turnover of 7 plant communities where small quantities of gneiss were present.
While on Alpine mature serpentine soils only Ni was associated with vegetation differences, P cannot be excluded from the important factors in early stages of serpentine ecosystem
Valutazione dello stato e della diversità dei suoli in alcuni siti caratteristici del Parco Parco: hot spot per lo stock di carbonio
No full textThe presentation shows the main soil properties (high carbon stock, high development degree, low erodibility) in Valgrande National Park, during the celebration for the Park's 30th birthday
High C stocks in Umbrisols in Valgrande National Park (NW Italy)
Full text linkValgrande National Park is characterized by a particularly high mean precipitation amount (up to 2500-3000 mm per year), and this factor contributes to the widespread presence of Umbrisols. In order to understand their distribution and pedogenesis, we opened and analyzed 19 soil profiles and observed many non-analyzed minipits under different land uses.
The results show that Umbrisols are indeed the most common soil types under most land uses. Cambisols can be observed only in highly disturbed positions, while Umbric Podzols can be found under heath. Commonly, Umbrisols also have a black Sombric Bh horizon below 30 cm of depth.
As expected on sialic parent materials under a very wet climate, the soils are extremely acidic and dominated by exchangeable Al.
The C stocks are high, with values commonly above 18-20 kg/m2, mainly located in the mineral horizons. There are no differences with land uses: the lowest C stocks were measured in disturbed soil profiles, where erosion or recent deposition made the soil less thick. 1-3 C kg/m2 are stored in organic layers, with the highest values measured in Umbric Podzols under heath. 40-60% of the total C stored in mineral horizons is located under 30 cm of depth, thus measuring its content only in the top 30 cm would lead to a huge underestimation of C stocks
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Genesi dei suoli nelle aree proglaciali del Monte Bianco: Miage e Pré de Bar = Soil genesis in the proglacial areas in Mont Blanc: Miage and Pré de Bar examples
No full textGli ambienti proglaciali dei ghiacciai di Miage e Pré de Bar, lasciati liberi durante l’arretramento dei ghiacci in periodi più o meno recenti, rappresentano due esempi estremamente diversi di sviluppo degli ecosistemi associato al cambio climatico. Le morene del ghiacciaio del Miage, in particolare, rappresentano uno dei rari esempi sulle Alpi di sviluppo dei suoli e della vegetazione su un’ampiezza temporale millenaria, a partire da 4000 anni fa circa. In particolare, la presenza di rocce metamorfiche in aggiunta al granito tipico del massiccio del Monte Bianco, rende il materiale più alterabile e i suoli si sviluppano in tempi molto rapidi, raggiungendo lo stadio maturo in poco più di 2000 anni (sulle Alpi, il tempo medio è di circa 5000 anni). La situazione è estremamente diversa nell’area proglaciale del Pré de Bar, dove il paesaggio rimane pressoche spoglio di vegetazione e i suoli estremamente poco evoluti per più di 190 anni.The proglacial environments of the Miage and Pré de Bar glaciers, deposited during ice retreat in more or less recent periods, represent two extremely different examples of ecosystem development associated with climate change. The moraines of the Miage glacier, in particular, represent one of the rare examples in the Alps of development of soils and vegetation over a millennial time span, starting about 4,000 years ago. In particular, the presence of metamorphic rocks in addition to the granite typical of the Mont Blanc massif makes the material more alterable, and soils develop very rapidly, reaching the mature stage in just over 2,000 years (in the Alps, the average time is about 5,000 years). The situation is extremely different in the Pré de Bar proglacial area, where the landscape remains almost free of vegetation and the soils extremely undeveloped for more than 190 years
Modelling soil removal from snow avalanches: a case study in the North-Western Italian Alps
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