The study objective was to derive a susceptibility model for shallow landslides that could include process-related non-stationary variables, to be adaptable to climate changes. We selected the ...territory of the Mont-Emilius and Mont-Cervin Mountain Communities (northern Italy) as the study area. To define summary variables related to landslide predisposing and triggering processes, we investigated the relationships between landslide occurrences and intense rainfall and snowmelt events (period 1991–2020). For landslide susceptibility mapping, we set up a Generalized Additive Model. We defined a reference model through variable penalization (relief, NDVI, land cover and geology predictors). Similarly, we optimized a model including the climate variables, checking their smooth functions to ensure physical plausibility. Finally, we validated the optimized model through a k-fold cross-validation and performed an evaluation based on contingency tables, area under the receiver operating characteristic curve (AUROC) and variable importance (decrease in explained variance). The climate variables that resulted as being statistically and physically significant are the effective annual number of rainfall events with intensity–duration characteristics above a defined threshold (EATean) and the average number of melting events occurring in a hydrological year (MEn). In the optimized model, EATean and MEn accounted for 5% of the explained deviance. Compared to the reference model, their introduction led to an increase in true positive rate and AUROC of 2.4% and 0.8%, respectively. Also, their inclusion caused a transition of the vulnerability class in 11.0% of the study area. The k-fold validation confirmed the statistical significance and physical plausibility of the meteorological variables in 74% (EATean) and 93% (MEn) of the fitted models. Our results demonstrate the validity of the proposed approach to introduce process-related, non-stationary, physically-plausible climate variables within a shallow landslide susceptibility analysis. Not only do the variables improve the model performance, but they make it adaptable to map the future evolution of landslide susceptibility including climate changes.
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•Intense rainfall and snowmelt were included in a landslide susceptibility analysis.•The statistical and physical importance of the variables was verified by a GAM.•The climate related variables together explained 5% of the model deviance.•The climate variables modified the susceptibility class in 11% of the study area.•These variables allow exploring climate change impacts on landslide susceptibility.
Recent studies have documented the presence of microplastics (MPs) in remote areas, including soils or sediments collected in mountain and glacier environments, but information on their presence in ...snow is scant. The present study aimed at exploring the presence of MPs in residual snow collected in four locations of the Aosta Valley (Western Italian Alps), with different accessibility and human presence. Overall, the µ-FTIR analyses confirmed the presence of 18 MPs in snow, 7 (39%) items were fibres, while 11 (61%) were fragments. Polyethylene (PE; 7 MPs) was the main polymer, followed by polyethylene terephthalate (PET; 3 MPs), high density PE (HDPE; 3 MPs), polyester (2 MPs), while only 1 MP made by low density PE, polypropylene and polyurethane were found. The mean (± SE) concentration of MPs in snow ranged between 0.39 ± 0.39 MPs/L and 4.91 ± 2.48 MPs/L, with a mean of 2.32 ± 0.96 MPs/L for the sampling locations. The concentration of MPs did not statistically differ among locations. Our results suggest that MPs presence in high-mountain ecosystems might depend on deposition through atmospheric precipitations or local sources due to human activities. For these reasons, policies aiming at reducing plastic use and dispersal in mountain areas may be effective in preventing local MP contamination.
The Megalithic Area of Saint‐Martin‐de‐Corléans (Aosta, northern Italy) consists of anthropomorphic stelae dated to the Copper Age and the beginning of the Early Bronze Age. They were carved in ...different lithologies of varying provenance according to two successive artistic styles, ‘ancient’ and ‘evolved’. A minero‐chemical and a petrographic investigation were carried out on 47 stelae and on reference samples collected from eight different outcrops, aiming to define the provenance of the stone materials. The variety of rocks used for the manufacture of the stelae reflects the geological complexity of the Aosta Valley. Most of the stelae examined were classified as foliated impure marbles, grey banded marbles (‘Bardiglio’), calcschists and metabasites belonging to the Combin Zone (Piedmont Nappe), which outcrops in close proximity to the Megalithic Area. Some stelae of the evolved group consisted of massive marbles with silicate‐bearing layers, attributed to the Sion–Courmayeur Zone. Similar stone materials were reported for the stelae of the same age found at the archaeological area of Petit Chasseur (Sion, Switzerland). This is archaeometric confirmation of the archaeological affinity between the stelae occurring at the two prehistoric sites, supporting the hypothesis of cultural exchanges over the Grand St Bernard Pass since the Early Copper Age.
This work presents the numerical modeling of remediation scenarios aimed at containing and attenuating the groundwater pollution by Cr(VI) sourced from a steelworks area that affects the Alpine ...aquifer system in the Aosta Plain (N Italy). Here, groundwater is used for drinking water supply and food and beverage production, so the adoption of remediation works is urgently needed. More specifically, three remediation scenarios were modeled using MODFLOW-2000 and MT3DMS: (a) the activation of a hydraulic barrier to contain the pollution within the source area (Scenario 1); (b) the removal of the pollution sources and the natural attenuation of the residual groundwater plume (Scenario 2); and (c) a combination of the previous two works (Scenario 3). Model results for Scenario 1 showed that a hydraulic barrier composed of five wells located along the eastern border of the steelworks area would contain Cr(VI) concentrations above 5 µg/L (i.e., the Italian regulatory limit) within the steelworks area; the barrier would have a total discharge of 27,500 m3/day, which could be compensated by the deactivation of three steelworks wells; the hydraulic barrier would drop the Cr(VI) concentrations below 5 µg/L in the areas downstream of the steelworks after ~3 years from its start of operation. Results for Scenario 2 highlighted that the removal of the Cr(VI) sources would drop the Cr(VI) concentrations below 5 µg/L in the areas downstream of the steelworks after ~2.5 years, and lead to a full remediation of the Cr(VI) groundwater plume (i.e., total Cr(VI) mass in the aquifer close to zero) after 17 years. Results for Scenario 3 showed that the removal of the Cr(VI) sources accompanied by the activation of the hydraulic barrier would led to a faster remediation within the first 14 years from the starting of the remediation works, with concentrations below 5 µg/L in the areas downstream of the steelworks obtained after ~2.3 years.
The Aosta cattle breeds have a key role in the economy of the Aosta Valley. In addition to the meat and milk production these autochthonous breeds are important for their cultural value, and for ...their role in the maintenance of the mountain environment. The knowledge of their genetic makeup represents a fundamental asset to managing the reproduction of the population in order to maintain the existing genetic diversity and, as a possible input, to apply genomic selection in a small population. A total of 3195 Aosta cows were genotyped with the GeneSeek Genomic Profiler® (GGP) Bovine 100K by Neogen in the framework of the DUALBREEDING-2 project. The Aosta Black-Chestnut and Chestnut-Herèn resulted to be a unique population. The Aosta female population had shorter ROH than bulls and shared ROH_islands that harbour adaptative and functional genes. Allele frequencies of major genes highlight the possibility for selection for both milk and meat quality variants and that the Aosta cattle population is free from the known Mendelian inheritance diseases found in cosmopolitan breeds (e.g. BLAD, CVM, HCD).
A groundwater flow model of the Alpine valley aquifer in the Aosta Plain (NW Italy) showed that well pumping can induce river streamflow depletions as a function of well location. Analysis of the ...water budget showed that ∼80% of the water pumped during 2 years by a selected well in the downstream area comes from the baseflow of the main river discharge. Alluvial aquifers hosted in Alpine valleys fall within a particular hydrogeological context where groundwater/surface-water relationships change from upstream to downstream as well as seasonally. A transient groundwater model using MODFLOW2005 and the Streamflow-Routing (SFR2) Package is here presented, aimed at investigating water exchanges between the main regional river (Dora Baltea River, a left-hand tributary of the Po River), its tributaries and the underlying shallow aquifer, which is affected by seasonal oscillations. The three-dimensional distribution of the hydraulic conductivity of the aquifer was obtained by means of a specific coding system within the database TANGRAM. Both head and flux targets were used to perform the model calibration using PEST. Results showed that the fluctuations of the water table play an important role in groundwater/surface-water interconnections. In upstream areas, groundwater is recharged by water leaking through the riverbed and the well abstraction component of the water budget changes as a function of the hydraulic conditions of the aquifer. In downstream areas, groundwater is drained by the river and most of the water pumped by wells comes from the base flow component of the river discharge.
This paper investigates and analyses social farming in the Aosta Valley, a tiny Italian mountain region in the Alps. It aims to highlight the features of social farming in this region, focusing on ...the social mission and economic sustainability.The paper first presents the literature on social farming, focusing on marginal and remote areas, and illustrating the main characteristics of Italian social farms. Secondly, it focuses on the findings coming from a qualitative investigation of three case studies of Valdostan social farms based on data collected from semi-structured direct interviews. The analyses reveal that social farming in the Aosta Valley fulfils a crucial social mission in areas with poor accessibility to social services.It is economically sustainable, basing its business model on the environmental and agricultural resources typical of high mountain regions.
Previous research on the Neolithic cist graves of the Western Alpine region—also known under the term Chamblandes type graves—mostly focused on sites located in western Switzerland and eastern ...France. For the adjacent Aosta Valley (Italy), only a little information is available. Within the framework of our research project, it was possible to identify about 120 stone cist graves from 10 sites in the Aosta Valley. Due to the lack of distinctive grave goods and missing absolute dating, however, their chronological position has been unclear until now. Here we present the first extensive series of radiocarbon dates from Neolithic stone cist graves of the Aosta Valley. We analyzed 31 human bone samples from four sites, and most dates indicate an unexpected early chronological position around the first half of the 5th millennium BCE, in particular, the site of Villeneuve, dating to 4800–4550 cal BCE. This identifies these burials from the Aosta Valley as belonging to the oldest known Neolithic cist graves of the Western Alpine region discovered so far. Altogether, our study provides new evidence allowing the first time to clarify the chronology of these sites and trace the evolution of this burial practice in the Western Alps.
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