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The Little Ice Age (LIA) is a well-recognized climatic event during which the glaciers in the Alps advanced and reached their maximum Holocene extent. During their retreat following the LIA, the glaciers left large areas of loose or poorly consolidated glacial deposits in their forelands, which are subject to paraglacial reworking and may represent potential hazards for human infrastructures. In this study, we present a regional scale mapping of the LIA and post-LIA glacial deposits and a reconstruction of the maximum LIA extents of glaciers in the same area. This work is motivated by a local law requiring the classification of areas subject to natural hazards in Trentino (Italian Alps). Results highlight that glaciers shrunk by 63% from the LIA maximum, leaving 30 km 2 of unconsolidated deposits, which are subject to geomorphic paraglacial processes. Potentially hazardous consequences can occur, in particular, during high-magnitude instantaneous events, causing debris and mud flows, mass wasting from debris-covered ice, and floods from small moraine-dammed lakes. [ABSTRACT FROM AUTHOR]

Field observations, old terrestrial photographs and maps, aerial orthophotos and detailed geomorphological mapping were used for compiling and validating a 119-year cumulative record of terminus changes for La Mare Glacier, Eastern Italian Alps. Late Holocene glacier maxima preceding direct observations were reconstructed by applying age dating techniques (radiocarbon and lichenometry) to glacial deposits in the proglacial area of the glacier. Results show that the glacier reached its maximal position around 1600 ad, followed by smaller advances in the eighteenth century, while in the nineteenth century it did not reach or overrun these positions. A similar behaviour for neighbouring glaciers was reported by previous works, documenting absolute Late Holocene maxima in the seventeenth or eighteenth centuries. By contrast, multi-century reconstructions available for the north-western Alps show that in the nineteenth century, glaciers were at their maximum or very close to previous maxima achieved in the first half of the seventeenth century. Climatic causes for these discrepancies have been examined, analyzing multi-proxy climatic reconstructions starting in 1500 ad, but also morphodynamic processes linked to the bedrock characteristics of La Mare Glacier could have played a role in modulating its response to climatic changes. [ABSTRACT FROM AUTHOR]

Geomorphological, morphotectonic, stratigraphical, structural and geological data were collected in the area between the Rivers Scrivia and Nure, the Po Plain and the headwaters of the Rivers Trebbia, Aveto and Borbera (northern Italy). The data were used to implement databases and to computerise geo-related thematic maps, which are easily comparable and readily updated. Reaches of the Borbera and Lambro Meridionale Rivers that show anomalous diversions were investigated in detail. Several thematic maps (geolithological, geomorphological, etc.) were constructed and overlain on the digital terrain model. The results of the processing (hillshade, slope, aspect, drainage, etc.) are important elements for identifying and reconstructing the main tectonic phases that have constrained the hydrography of the area. [Copyright &y& Elsevier]

In this work, we present the geological map of the San Pellegrino pass, inserted in the spectacular scenario of the Dolomiti region (Southern Alps, Italy), at a scale of 1:10.000 and accompanied by geological cross-sections. The detailed distinction of lithological thin units allowed to achieve a consistent interpretation of the local structural setting by drawing brittle and ductile Alpine tectonic deformations. The differential deformation and structural styles within the geological map are the result of the different rheological nature of volcanic and sedimentary rocks, as well as of the superimposition of compressional Alpine tectonics over Permo-Mesozoic extensional tectonic phases, and consequent reactivation of inherited structures. [ABSTRACT FROM AUTHOR]

A pronounced climate reorganization characterized the Lateglacial-Holocene transition in the Northern Hemisphere. Glaciers in the Alps reacted to the last climate deterioration at the end of the Late Pleistocene leaving landscape features suitable for reconstructing Lateglacial and early Holocene history. In this context, the Upper Peio Valley in the Ortles-Cevedale Group (Rhaetian Alps, Italy) has well-preserved moraines of La Mare Glacier and Careser Glacier, which we used to reconstruct the glaciers' behaviour and to investigate the Lateglacial-Holocene transition. Detailed glacier reconstructions combined with 11 new 10Be exposure ages allow dating of the response of these glaciers to the Younger Dryas ( YD) cold event. La Mare and Careser glaciers reacted to the YD with a double response, building two clear moraine sets. Data from La Mare Glacier indicate the first advance occurred prior to 12.3±0.7 ka (before 10.0±0.7 ka at Careser Glacier). Both glaciers then re-advanced before 11.2±0.8 ka as dated at La Mare Glacier. This phase can be interpreted as the Egesen stadial glaciers' expression of the end of the YD. Morphometric parameters of the reconstructed phases allowed the estimation of areal and volumetric variations of the studied glaciers as well as equilibrium line altitude ( ELA). Δ ELA with respect to the Little Ice Age ( LIA) maximum position are −225 m for La Mare Glacier and −180 m for the Careser Glacier. Although the behaviour of the two glaciers showed coherence during the Egesen stadial and the LIA, they have behaved individually since then. La Mare has lost 60% of its area, while Careser has lost 85% since the latest Pleistocene. We attribute this to the greater proportion of ice at high elevation of the La Mare Glacier, underlining the importance of bed hypsometry in glacier response. [ABSTRACT FROM AUTHOR]

In 2011 four ice cores were extracted from the summit of Alto dell'Ortles (3859 m), the highest glacier of South Tyrol in the Italian Alps. This drilling site is located only 37 km southwest from where the Tyrolean Iceman, ~5.3 kyrs old, was discovered emerging from the ablating ice field of Tisenjoch (3210 m, near the Italian-Austrian border) in 1991. The excellent preservation of this mummy suggested that the Tyrolean Iceman was continuously embedded in prehistoric ice and that additional ancient ice was likely preserved elsewhere in South Tyrol. Dating of the ice cores from Alto dell'Ortles based on 210Pb, tritium, beta activity and 14C determinations, combined with an empirical model (COPRA), provides evidence for a chronologically ordered ice stratigraphy from the modern glacier surface down to the bottom ice layers with an age of ~7 kyrs, which confirms the hypothesis. Our results indicate that the drilling site has continuously been glaciated on frozen bedrock since ~7 kyrs BP. Absence of older ice on the highest glacier of South Tyrol is consistent with the removal of basal ice from bedrock during the Northern Hemisphere Climatic Optimum (6-9 kyrs BP), the warmest interval in the European Alps during the Holocene. Borehole inclinometric measurements of the current glacier flow combined with surface ground penetration radar (GPR) measurements indicate that, due to the sustained atmospheric warming since the 1980s, an acceleration of the glacier Alto dell'Ortles flow has just recently begun. Given the stratigraphic-chronological continuity of the Mt. Ortles cores over millennia, it can be argued that this behaviour has been unprecedented at this location since the Northern Hemisphere Climatic Optimum. [ABSTRACT FROM AUTHOR]

This work presents an analysis of the mass balance series of nine Italian glaciers, which were selected based on the length, continuity and reliability of observations. All glaciers experienced mass loss in the observation period, which is variable for the different glaciers and ranges between 10 and 47 years. The longest series display increasing mass loss rates, which were mainly due to increased ablation during longer and warmer ablation seasons. The mean annual mass balance (Ba) in the decade from 2004 to 2013 ranged from -1788 to -763 mm w.e. yr-1. Low-altitude glaciers with low range of elevation are more out of balance than the higher, larger and steeper glaciers, which maintain residual accumulation areas in their upper reaches. The response of glaciers is mainly controlled by the combination of October-May precipitations and June-September temperatures, but rapid geometric adjustments and atmospheric changes lead to modifications in their response to climatic variations. In particular, a decreasing correlation of Ba with the June-September temperatures and an increasing correlation with October-May precipitations are observed for some glaciers. In addition, the October-May temperatures tend to become significantly correlated with Ba, possibly indicating a decrease in the fraction of solid precipitation, and/or increased ablation, during the accumulation season. Because most of the monitored glaciers have no more accumulation area, their observations series are at risk due to their impending extinction, thus requiring a replacement soon. [ABSTRACT FROM AUTHOR]

Smaller glaciers (<0.5 km2) react quickly to environmental changes and typically show a large scatter in their individual response. Accounting for these ice bodies is essential for assessing regional glacier change, given their high number and contribution to the total loss of glacier area in mountain regions. However, studying small glaciers using traditional techniques may be difficult or not feasible, and assessing their current activity and dynamics may be problematic. In this paper, we present an integrated approach for characterizing the current behaviour of a small, avalanche-fed glacier at low altitude in the Italian Alps, combining geomorphological, geophysical and high-resolution geodetic surveying with a terrestrial laser scanner. The glacier is still active and shows a detectable mass transfer from the accumulation area to the lower ablation area, which is covered by a thick debris mantle. The glacier owes its existence to the local topo-climatic conditions, ensured by high rock walls which enhance accumulation by delivering avalanche snow and reduce ablation by providing topographic shading and regulating the debris budget of the glacier catchment. In the last several years the glacier has displayed peculiar behaviour compared with most glaciers of the European Alps, being close to equilibrium conditions in spite of warm ablation seasons. Proportionally small relative changes have also occurred since the Little Ice Age maximum. Compared with the majority of other Alpine glaciers, we infer for this glacier a lower sensitivity to air temperature and a higher sensitivity to precipitation, associated with important feedback from increasing debris cover during unfavourable periods. [ABSTRACT FROM AUTHOR]

Summary: Analyses of event runoff coefficients provide essential insight on catchment response, particularly if a range of catchments and a range of events are compared by a single indicator. In this study we examine the effect of climate, geology, land use, flood types and initial soil moisture conditions on the distribution functions of the event runoff coefficients for a set of 14 mountainous catchments located in the eastern Italian Alps, ranging in size from 7.3 to 608.4km2. Runoff coefficients were computed from hourly precipitation, runoff data and estimates of snowmelt. A total of 535 events were analysed over the period 1989–2004. We classified each basin using a “permeability index” which was inferred from a geologic map and ranged from “low” to “high permeability”. A continuous soil moisture accounting model was applied to each catchment to classify ‘wet’ and ‘dry’ initial soil moisture conditions. The results indicate that the spatial distribution of runoff coefficients is highly correlated with mean annual precipitation, with the mean runoff coefficient increasing with mean annual precipitation. Geology, through the ‘permeability index’, is another important control on runoff coefficients for catchments with mean annual precipitation less than 1200mm. Land use, as indexed by the SCS curve number, influences runoff coefficient distribution to a lesser degree. An analysis of the runoff coefficients by flood type indicates that runoff coefficients increase with event snowmelt. Results show that there exists an intermediate region of subsurface water storage capacity, as indexed by a flow–duration curve-based index, which maximises the impact of initial wetness conditions on the runoff coefficient. This means that the difference between runoff coefficients characterised by wet and dry initial conditions is negligible both for basins with very large storage capacity and for basins with small storage capacity. For basins with intermediate storage capacities, the impact of the initial wetness conditions may be relatively large. [Copyright &y& Elsevier]

Abstract: Cluster analysis of 245 vegetation plots, along 17 transects on alpine composite debris cones in the Italian Alps, allowed us to classify complex mosaics of landforms and plant communities. A variety of active and past geomorphic processes (mass wasting, avalanche activity, and running water) were responsible for the construction of the debris cones. By assessing plant community distribution in the context of the different landform units and geomorphic processes, represented in detailed geomorphological maps, a sequence of landform–vegetation units was identified. This approach contributes to the assessment of environmental hazards on the cones, and may also be applied in other environmental contexts. Plant community distribution and development in Valle dell''Avio reflects the frequency and intensity of the processes that built composite alpine debris cones, creating environmental gradients and/or generating new habitats. Therefore this patchy landscape allows the preservation of local biodiversity, with typical plant communities adapted to particular niches. [Copyright &y& Elsevier]

• In the study area glaciers have lost 50% of their total surface since LIA. • Slope processes favour alpine plant colonization across the treeline ecotone. • Microrefugia offer climatic shelter reducing the extinction risk for alpine species. • Alpine plants could be less prone to decline than predicted by ecological models. The temperature rise at the global level and glacier shrinkage are deemed to induce new dynamics between biotic and abiotic factors, especially in mountain regions. In this work, we aimed to assess: (a) the area made available after glacier retreat since the Little Ice Age (LIA) for the colonization of alpine plants; (b) the ability of 14 alpine and nival species, typically growing on peaks and in deglaciated areas, to migrate and survive at lower elevations in microrefugia across the treeline ecotone. In the Adamello-Presanella Massif (Rhaetian Alps), we collected presence data on 14 alpine species within 3 × 3 or 5 × 5 m plots according to slope landforms and deposits. The analysis of the elevation range of the investigated species across the treeline was performed using Sentinel-2 satellite images to derive the actual position of the upper and lower treeline. The differences in the species elevation ranges across slope landforms, in relation to the treeline elevation and aspect, were detected with linear mixed models. Results showed that glaciers contracted sharply by more than 50% between the LIA and 2006, making large deglaciated areas available (more than 57 km2). All the studied species were found at low altitudes across the treeline ecotone, from about 500 to 1200 m below their typical habitat. Six species (Cardamine resedifolia , Cerastium uniflorum , Leucanthemopsis alpina , Luzula alpinopilosa , Oxyria digyna , Saxifraga oppositifolia) significantly exceeded the upper treeline in correspondence of alpine composite channels (p < 0.001 for all species). One species (Adenostyles leucophylla) exceeded the upper treeline in correspondence of composite slope deposits (p < 0.05). Two species (Ranunculus glacialis and S. oppositifolia) reached the lower treeline in composite channels and slope deposits (p = 0.800, and p = 0.519, respectively). The retreat of the alpine glaciers, coupled with the intensification of paraglacial processes, may favor new habitat opportunities at high elevation and microrefugia at low altitudes for nival and alpine species. The widespread presence of microrefugia for alpine plants downslope during warm periods suggests a low incidence of biodiversity loss in the alpine regions due to climate change. [ABSTRACT FROM AUTHOR]

Glacierized catchments are essential sources of fresh water in Alpine areas especially duringwarm and dry periods. Therefore, the quantification of glacier melt contribution to streamrunoff represents a crucial issue in Alpine catchments affected by rapid glacier shrinking. Theglacier melt water contribution to stream runoff can be estimated by different approaches, oneof which is represented by the application of geochemical tracers. However, the spatial andtemporal characterization of geochemical tracers in water sources in glacierized catchments isparticularly difficult. In this work, we aim to characterize the tracer signature (δ2H and electrical conductivity(EC)) of the main water sources and study the hydrological response of a glacierizedcatchment during three consecutive summer seasons. The specific objectives are to: i) analyzethe spatial and temporal variability of the tracer signature of snow, glacier ice and glacier meltwater, in relation to the fractional snow cover of the catchment, ii) analyze the inter-annualand seasonal dynamics of streamflow, stream water EC and isotopic composition in relationto the hydro-meteorological conditions, and iii) identify the main end-members to streamrunoff. The study area is an 8.4-km2 catchment (42% glacierized) in the Eastern Italian Alps.Meteorological and streamflow data were collected continuously during the 2013-2015ablation seasons. Samples for EC and isotopic analyses were taken from rainfall at the outletof the catchment and from fresh and residual winter snow, firn, glacier ice and melt water atdifferent elevations on the glacier. Stream water samples were taken manually andby an automatic sampler at the outlet, and from three sections close to the glacierfronts. Results showed that variations in the daily streamflow range due to melt-induced runoffevents were controlled by maximum daily air temperature and snow covered area in thecatchment. Maximum daily streamflow decreased with increasing snow cover and a thresholdrelation was found between maximum daily temperature and daily streamflow range. Therewas a high spatial and temporal variability in the isotopic composition of snow, glacierice and glacier melt water. The isotopic composition of snow, glacier ice and meltwater was not significantly correlated with the sampling point elevation and thespatial variability was more likely affected by post-depositional processes. Duringmelt-induced runoff events, stream water EC decreased due to the contribution ofglacier melt water to stream runoff. In this catchment, EC or more conservativetracers could be used to distinguish the contribution of subglacial flow (enriched inEC) from glacier melt water to stream runoff at the seasonal and daily timescale.The high spatial and temporal variability in the tracer signature of the identifiedend members (subglacial flow, rain water, glacier melt water and residual wintersnow), together with small daily variability in stream water δ2H dynamics, areproblematic for the quantification of the contribution of the end members to streamrunoff, and call for further research, possibly integrated with other natural or artificialtracers. Keywords: runoff generation; stable water isotopes; electrical conductivity; end members;glacier; snow; Alpine catchment. [ABSTRACT FROM AUTHOR]