Italian Prealps Research Articles

Caratterizzazione geotecnica e mineralogica di depositi vulcanici alterati soggetti a fenomeni di scivolamento nell’area pedemontana della Provincia di Vicenza

The main aim of this study is to investigate triggering mechanism of landslides which widely affect altered volcanic rocks outcropping in the Italian pre-Alps of Vicenza province. To this end, geotechnical and mineralogical tests were performed. The results show how the variation of mineralogical properties of the soils influences the stability of the involved slopes. Based on this finding, numerical simulations have been carried on to evaluate the influence of mineralogical properties on the decay of strength parameters.

Habitat management effects on Prealpine grassland bird communities

Currently, land abandonment constitutes a serious threat for many species tied to semi-natural grasslands. In southern Europe, the conservation of many grassland bird communities largely depends on low-intensity mountain farming. In this study, we analysed the effects of the main farming practices promoting grassland maintenance, i.e. grazing and mowing, on species richness of a Prealpine grassland bird community and on the breeding densities of the two commonest grassland species, the skylark (Alauda arvensis Linnaeus, 1758) and the tree pipit (Anthus trivialis Linnaeus, 1758). The two study sites were located between 1100 and 2000 m above sea level in the Italian central Prealps. Grassland species richness was positively affected by grazing, and increased with increasing distance from the nearest woodland. Skylark density was positively influenced by mowing, grassland cover extent and distance from woodland, with the latter effect occurring only at a single study site. Finally, tree pipit density was positively affected by grazing. Our findings suggest that, in order to maintain open grasslands below the natural treeline and enhance the biodiversity of grassland bird communities, grazing should be preferred over mowing. Moreover, woodland edge effects may have a negative impact on mountain grassland bird communities. Advancing woodlands and abandonment of low-intensity farming and grazing practices may therefore constitute a serious threat for open-habitat specialist bird species of the Alpine region.

Detecting human presence at the border of the Northeastern Italian Pre-Alps. 14C dating at Rio Secco cave as expression of the first Gravettian and the late mousterian in the Northern Adriatic Region.

In the northern Adriatic regions, which include the Venetian region and the Dalmatian coast, late Neanderthal settlements are recorded in few sites and even more ephemeral are remains of the Mid-Upper Palaeolithic occupations. A contribution to reconstruct the human presence during this time range has been produced from a recently investigated cave, Rio Secco, located in the northern Adriatic region at the foot of the Carnic Pre-Alps. Chronometric data make Rio Secco a key site in the context of recording occupation by late Neanderthals and regarding the diffusion of the Mid-Upper Palaeolithic culture in a particular district at the border of the alpine region. As for the Gravettian, its diffusion in Italy is a subject of on-going research and the aim of this paper is to provide new information on the timing of this process in Italy. In the southern end of the Peninsula the first occupation dates to around 28,000 14C BP, whereas our results on Gravettian layer range from 29,390 to 28,995 14C years BP. At the present state of knowledge, the emergence of the Gravettian in eastern Italy is contemporaneous with several sites in Central Europe and the chronological dates support the hypothesis that the Swabian Gravettian probably dispersed from eastern Austria.

Use of morphological features and amarogentin content for characterization of wild yellow gentian (Gentiana lutea L.) populations in north-east Italy

During the summer of 2010, a survey aiming to assess the morphological characteristics and the amarogentin content of different wild populations of yellow gentian (Gentiana lutea L.) was carried out in the south-eastern Italian Pre-Alps (1050–1950 m above sea level). The focus of the survey was the province of Trento where seven populations were recorded. Two more populations were recorded in the province of Brescia, which represented the southern and western limit of the targeted area, respectively. The last two populations were found in the province of Vicenza and Pordenone, the latter corresponding to the eastern boundary of the research area. A series of qualitative and quantitative parameters were recorded for each site/population and univariate (Kruskall–Wallis test) and multivariate (principal component analysis and cluster analysis) analyses were performed to estimate differences between populations. According to the descriptors recorded, a large variability emerged among all the targeted populations, nine of which belonged to the subsp. lutea and vardjanii Wraber complex, whereas the two populations from Vicenza and Pordenone provinces belonged to the subsp. symphyandra Hayek. These last are characterized by a later flowering, larger corolla lobes, and taller stems and roots, and are richer in amarogentin compared with the other populations.

Tracing the Water Sources of Trees and Streams: Isotopic Analysis in a Small Pre-Alpine Catchment

We used a dual stable isotope approach (2H and 18O) and electrical conductivity data in combination with hydrometric measurements to trace water fluxes in the soil, stream and trees in a small forested watershed in the Italian Pre-Alps. The aim was to understand the main water sources for plant transpiration and runoff generation. The data were collected between events and during rainfall events in order to assess the sources of tree uptake under different conditions. Sampling and analysis are still continuing but preliminary results show that the isotopic composition of tree water was similar to soil water and rain water but statistically different from streamflow and groundwater. This suggests that trees used predominantly soil water, rather than groundwater, during the study period. No marked difference was found between the isotopic composition of the sap of trees in the riparian zone and the sap of trees on the hillslope. However, during dry conditions sap in riparian trees slowly became more similar to deep soil water and groundwater, indicating a possible switch in water uptake from shallow to deeper soil water. In contrast to the quick response of the stream, the composition of tree water did not change immediately after a rainfall event, even though the composition of shallow soil water had changed, which may be caused by storage of water in the tree and the low vapor pressure deficit that suppressed transpiration after the rainfall event. Future work will be carried out to monitor the seasonal variability in water uptake and its response to rainfall events in more detail.

A landscape genetics approach reveals ecological-based differentiation in populations of holm oak (Quercus ilex L.) at the northern limit of its range

The holm oak plays a relevant role in the functioning of Mediterranean forests. In the area north of Garda Lake, Italian Prealps, holm oak populations are at the northernmost edge of their distribution. Being peripheral, these populations are of particular interest for ecological, evolutionary and conservation studies. Through an explicit individual-based landscape genetics approach, we addressed the following questions: (1) are levels of genetic variation reduced in these marginal populations compared with central populations?; (2) despite the narrow geographical scale, do individual-based analyses have some power to detect genetic differentiation?; (3) do environmental and/or climatic factors exert a role in shaping patterns of genetic variation and differentiation? Through a Bayesian method, we identified three clusters whose genetic variability can be considered to be of the same order as that recorded in central Quercus ilex populations. Although being geographically very close (< 20 km), the differentiation was statistically significant (P < 0.05) with global F st and Φ Pt values of 0.019 and 0.038, respectively. Geography and phylogeography could not be invoked to explain this differentiation. A redundancy discriminant analysis revealed that relevant eco-pedological and climatic features, such as soil depth, aspect, elevation and humidity, were correlated with the observed pattern of differentiation. Toblino was ecologically separated from the other clusters, as it lies on deep soil with subhumid conditions. The differentiation of the Brione–Ranzo–Val Busa cluster appeared to be related to superficial soils and drier conditions, whereas the Nanzone–Padaro cluster was differentiated mainly according to its mid-elevation. Coupling spatial and genetic information on a local scale proved to be effective to investigate the evolutionary and demographic history of peripheral populations. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ••, ••–••.

Chironomids as bioindicators of environmental quality in mountain springs

Abstract. We analyzed responses of chironomid (Diptera:Chironomidae) communities to environmental factors in 124 natural, moderately, and highly disturbed springs in the Italian Prealps and Alps to investigate environmental factors influencing species distribution in springs and to evaluate chironomids as bioindicators of spring water quality. Self-Organizing Map analysis found differences among spring types and effects of anthropogenic pressures. Natural or little-disturbed springs at high altitude with low temperature, low conductivity, and high current velocity differed from lowland springs, including highly disturbed ones, with low current velocity and higher temperature, conductivity, and nutrient concentrations. Cold stenothermal intolerant species were clustered in the 1st group, tolerant and euriecious species in the 2nd group. Indicator value analysis detected species characterizing springs with different degrees of disturbance and of different types. Most species' distributions were related to ...

Wild red deer [Cervus elaphus L.) grazing may seriously reduce forage production in mountain meadows

This study aimed at estimating the impact of red deer grazing on the productivity of meadows located in Pian Cansiglio, north-eastern Italian Pre-Alps. These meadows (185 ha; average elevation 1000 m asl are managed for hay/silage production (1–2 cuts per season) and are included in a protected area that hosts a high density of deer (around 30 heads/100 ha). In 2008 and 2010, dry matter (DM) production and loss due to deer grazing were estimated with exclusion cages (1 m2; 48 exclusion cages in 2008 and 52 in 2010). Night counts with spotlights were conducted to index deer use of meadows plots. DM production inside the cages was fairly good for the area (first-second cut: 4963-2297 kg DM/ha in 2008, and 4145-2475 kg DM/ha in 2010). DM production outside the cages was significantly lower (first-second cut in 2008: 4199-1378 kg DM/ha, and in 2010: 3376-2052 Kg DM/ha). Therefore, the magnitude of losses was of 15–20% at the first and 25–40% at the second cut. DM losses in the different meadow plots were positively correlated with index of deer use, which in some plots was as high as 7–8 heads/ha. Deer grazing reduced also crude protein (CP) content of forage (15.6±4.4% DM inside exclusion cages and 13.8±3.5% DM outside), with losses being greater where CP content was higher. This study demonstrates that high densities of grazing deer may seriously impact on forage production and quality.

Diversity and distribution of chironomids (Diptera, Chironomidae) in pristine Alpine and pre-Alpine springs (Northern Italy)

The diversity and distribution of chironomids (Diptera, Chironomidae) were studied in relation to environmental factors in 81 springs under pristine conditions in the Italian Prealps and Alps (Trentino and Veneto, NE-Italy, 46°N, 10-11°E). Each spring was surveyed once, between May and November, in 2005 or in 2007-2008, within 50 m of the spring's source (eucrenal). A total of 173 macroinvertebrate samples were collected, in which 26,871 chironomids (including larvae, pupae, pupal exuviae and adults) were counted. Five subfamilies (Tanypodinae, Diamesinae, Prodiamesinae, Orthocladiinae and Chironominae), 54 genera and 104 species/groups of species were identified. As expected, Orthocladiinae accounted for a large part of specimens (82%), followed by Diamesinae (10%), Chironominae Tanytarsini (6%) and Tanypodinae (2%). Together the Chironominae Chironomini and Prodiamesinae contributed less than 0.05% of the fauna. Larvae represented 97.5% of specimens, mostly juveniles (62.6%). Maximum richness and diversity occurred at intermediate altitudes (ca 900-2100 m a.s.l.). Most taxa were found in a small proportion of sites, and frequencies declined gradually for more widely distributed species. A high number (67%) of rare (= present in less than 10% of sites) taxa were found. Three to 27 taxa were identified per spring. The rheocrene/rheo-helocrene springs were richest in taxa (generally &gt;15 taxa), the mineral spring was poorest, with only three taxa. Most taxa were crenophilous, including lentic, rheobiontic and bryophilous taxa. A Principal Component Analysis (PCA) was performed including 98 taxa. Axes were interpreted calculating the correlation coefficients between site scores and 24 environmental factors. The species with the highest scores were Pseudokiefferiella parva, Corynoneura sp. A, Metriocnemus eurynotus gr., Paratrichocladius skirwithensis and Tvetenia calvescens. Five clusters of sites were identified with K-means analysis on the basis of the first and second PCA axes and a Discriminant Analysis was used to detect environmental factors discriminating the clusters: altitude, canopy cover, hydrological regime, pH, and granulometry as percentage of cobbles and stones. The highly individual nature of springs was highlighted; within the same river basin, between springs and within a single spring. These results suggest that prudent and conservative land management should assume that all springs sheltering such unique faunal assemblages need protection.

Forest ecosystem carbon accumulation during a secondary succession in the Eastern Prealps of Italy

Summary Land use changes represent one of the most important components of global environmental change. In most European countries, the transformed economies and social conditions of previous decades have had consequences in terms of agriculture intensifi cation, industrialization and migration of people from the rural areas. As a consequence, areas of marginal agriculture were abandoned leading to secondary successions. This research studied the effects of the natural recovery of abandoned lands on carbon pools using a chronosequence approach of mixed ash ( Fraxinus excelsior L.) and sycamore ( Acer pseudoplatanus L.) stands in the Eastern Italian Prealps. A series of fi ve formerly cultivated sites spanning a range of 40 – 75 years since agricultural abandonment and a meadow were selected. The dominant sink for the atmospheric CO 2 within these secondary forests seems to be live wood while the soil played a much smaller role. The ecosystem carbon stock increased at a mean rate of 1.18 Mg C ha − 1 y − 1 during the chronosequence. However, a difference in the carbon accumulation in the different pools was detected.

The response of epiphytic lichens to air pollution and subsets of ecological predictors: A case study from the Italian Prealps

We investigated the response of epiphytic lichens to air pollution, against the background of other ecological predictors in a prealpine heterogeneous area, using Non-Parametric Multiplicative Regression (NPMR). The best NPMR model for total lichen diversity according to N environmental predictors at tree level has a cross R 2 = 0.709. It includes 10 variables, belonging to three different subsets of factors: two pollution-related factors (distance in meters from the road and from the cement factory); four stand-related (habitat, heat index, LAI and elevation) and four substrate-related factors (inclination, circumference and texture and tree species). Considering separately the effects of each subset on lichen diversity, substrate- and stand-related factors produce good models with similar cross R 2 (0.490 and 0.500, respectively), whereas pollution-related factors produce a model with a lower cross R 2 (0.340). Hence, we provide information to investigate the applicability of lichen biomonitoring to complex heterogeneous areas where standardized protocols are not reliable.

Isolation and characterization of microsatellites in Primula glaucescens Moretti and their cross-species amplification in P. spectabilis Tratt.

The hexaploid herbaceous species Primula glaucescens Moretti and Primula spectabilis Tratt. (2n = 6x = 66) are two endemics of the Italian Pre-Alps protected by national and international laws. In order to plan conservation strategies for natural populations and to study the influence of the latest glaciation on them we developed a set of microsatellites markers for the endangered Primula species: ten primer pairs allowed analysis of polymorphic disomic loci in P. glaucescens samples and seven of them also amplified polymorphic disomic markers in P. spectabilis.

Forecasting hazard scenarios and implications for the evaluation of countermeasure efficiency for large debris avalanches

The key objective of a slope failure study is to reduce deaths, injuries and property damage. Predictions of slope failures are mandatory to reduce hazard and vulnerability of elements at risk with appropriate warning policy and properly designed countermeasures. Numerical modelling has been recently used as an approach to back-analyse real events but few attempts have been carried out to forecast potential failure scenarios. Recently, a debris avalanche involving about 1.2 million m 3 of debris and a nearby debris slide flow with failure volume of 0.1 million m 3 occurred in the Italian Prealps from the accumulation of a paleo-landslide. Field surveys and monitoring revealed that the upper part of the slope above the largest recent landslide is unstable with a possible failure volume between 1 and 1.5 million m 3. We conducted comprehensive fieldwork and analyses including geological and geomorphological surveys, compilation of a landslide inventory map, collection of rainfall records, study of triggering mechanisms and geotechnical properties of the failed materials, slope stability analyses and back-analyses of the runout phase of the landslide events. Through a series of slope stability analyses, the possible failure volume, sliding surface and topography are estimated, consistent with field monitoring data. Furthermore, with the help of calibration through back-analyses of the past landslide events, we assign a given degree of danger to slope elements with analogous conditions. We then numerically predict the runout patterns and mobility of the potential instabilities. The effectiveness of the planned passive countermeasures for potential zoning management is evaluated.

The lacustrine deposits of Fornaci di Ranica (late Early Pleistocene, Italian Pre-Alps): stratigraphy, palaeoenvironment and geological evolution

An interdisciplinary investigation of the Pleistocene clay succession of Fornaci di Ranica (Italian Pre-Alps) aimed to reconstruct the palaeoenvironmental history and its chronostratigraphic position and to consider the implications for the Quaternary evolution of the southern alpine borderland near the Early/Middle Pleistocene transition. A detailed survey of Quaternary deposits in boreholes and exposed sections provided a complete record of the basin. The most complete core was analyzed for palynology and magnetic properties. Plant macrofossils were obtained by flotation. Pollen and spectrometric analysis allowed a precise stratigraphic placement of a moose antler and braincase kept in museum collections. The basin originated from fluviatile obstruction of a tributary valley cut into bedrock. The basal deposits formed as a terrestrial hydromorphic soil under a dense Tsuga-forest (zone RNC 1). The overlying palustrine gyttja shows a marked forest withdrawal with a climatic signature (zone RNC 3), followed by a re-establishment of mixed conifer forests (zones RNC 4–6). The occurrences of pollen of cold-adapted taxa ( Saxifraga oppositifolia type, Saxifraga stellaris type, Larix), are the oldest so far known south of the Alps and suggest that mean summer temperature was near or even below the thermic tree limit. High herb diversity, partially represented by tall forbs, characterizes this zone. A further increase of the water table can be assumed in zones RNC 4 and RNC 5, since pollen of aquatic plants increases. The find of Larix decidua L. cones demonstrates the existence of the European larch in the Early Pleistocene of the Alps, previously not identified at the species level. After the Serio river had reached the maximum Quaternary aggradation, the lake was rapidly filled up with turbiditic sediments. The identification of Cervalces latifrons (Johnson, 1874) by Azzaroli (Palaeantogr. Italica 71(1979) 48) was confirmed. Pollen spectra obtained from clay fragments preserved in the braincase allowed us to constrain the stratigraphic position of these fossil remains in the lower palustrine portion of the sequence. Pollen and moose palaeoecology corroborate the reconstruction of a boreal landscape. The succession of Fornaci di Ranica is attributed to the late Early Pleistocene on the basis of the following elements: (i) the occurrence of an acme pollen zone of Tsuga, with Carya and Pterocarya; (ii) the low representation of Cedrus; (iii) the biochronology of Cervalces latifrons; (iv) normal fossil magnetic polarity, interpreted as part of the Jaramillo subchron on the basis of correlations with other studied sections from the same region, and, finally, (v) indications from the regional geological evolution. The basin deposits spanned the final stage of a temperate period and the subsequent transition to a cold phase during the Jaramillo subchron or the Cobb cryptochron. The basin originated by fluvioglacial aggradation, triggered by glaciation in the northern part of the Serio river catchement. The lake succession may represent an episode of marked increase of polar ice volume related to MIS (36) 30, or 28. The correlation with the Leffe sequence also suggests that cold climate conditions inferred for pollen zone RNC 3 did not occur earlier in the Early Pleistocene of this region.

Comparative analysis of two edaphic zoocoenoses (Acari Oribatida; Hexapoda Collembola) in the area of Orio al Serio Airport (Bergamo, northern Italy)

Species richness, abundance and diversity of oribatid mites and springtails in soil and litter were investigated at four sites in the area of Orio al Serio Airport (Bergamo, Italy). A total of 60 oribatid mite and 35 springtail species were collected from the sites. The general low diversity and evenness along with high dominance may be related to the sensitivity of these edaphic zoocoenoses to soil impoverishment which has been occurring in this part of the Italian pre-Alps for many years. Quantitative and qualitative differences were found among the investigated areas. Results show that less frequently disturbed soils are capable of restoring oribatid and springtail populations, leading to greater equilibrium. Results show that less frequently disturbed soils allow the restoration of more equilibrated oribatid and springtail populations. Species were divided into 8 autoecological and 11 chorological categories. Correspondence Analysis arranged these categories among the sites, confirming the above-mentioned trend.

Adaptive selection of foraging and nesting habitat by black kites ( Milvus migrans) and its implications for conservation: a multi-scale approach

Black kites ( Milvus migrans) are vulnerable and in decline within Europe. Here, we investigate selection of foraging and breeding habitat in a high-priority population in the Italian pre-Alps. Compared to a random distribution, kites foraged preferentially near water, over extensively managed grassland and within 1 km of nest-sites. Urban areas were positively selected near lakes but otherwise avoided. Foraging performance was higher over water than over terrestrial habitats. Kites nested on cliffs and trees and preferentially near water, far from paths and villages and in rugged and steep micro-sites. Tree-nests were located in the most mature tree in the stand. Productivity was positively related to the availability of water bodies. Therefore, food availability and human disturbance/persecution limited foraging and breeding performance. Guidelines to maintain or enhance current population levels include: (1) setting up reserves covering 10% of the areas within 1 km of large lakes; (2) converting current derelict coppice-woodland to high forest; and (3) enhancing subsidies for extensively managed grassland. Our results highlight the importance of cross-scale models integrating selection of foraging and breeding habitat and reinforce the importance of the spatial configuration of key resources for more realistic conservation management in mosaic landscapes.

Diet of the Eurasian badger (&lt;em&gt;Meles meles&lt;/em&gt;) in an area of the Italian Prealps

Samples of Eurasian badger faeces (n= 147) were collected at monthly intervals from Oc- tober 1997 to December 1999 in an area of the Italian Prealps (58 h2), on the eastern coast of Lario (Como Lake). The altitude of the area ranged from 200 to 1300 m. Badger scats were analysed to estimate the relative volume and the frequency of occurrence of iden- tifiable food items. Fruits, arthropodes, earthworms and mammals constituted the main food cate- gories. Differences were found between the seasonal frequency of occurrences of arthropodes, earth- worms and mammals, considering however that the small sample size in summer does not allow any definitive conclusions. The wide range of food items eaten by badgers and the seasonal differences would suggest that the badger is a generalist species which adopts an opportunist feeding strategy.

Radon Indoor Measurements: Results from Sites in the Italian Prealps

Radon Indoor Measurements: Results from Sites in the Italian Prealps

Radon Indoor Measurements: Results from Sites in the Italian Prealps

Radon Indoor Measurements: Results from Sites in the Italian Prealps