Manuela Pelfini

Epigean Arthropod Succession along a 154-year Glacier Foreland Chronosequence in the Forni Valley (Central Italian Alps)

Abstract The 154-year (1850–2004) chronosequence of the Forni Glacier foreland has been studied by sampling ant, centipede, ground beetle, and spider species assemblages. Species numbers increase with terrain age along the chronosequence from 2 to 26 on the oldest soils. Thirty-nine species were collected; species richness and diversity (Shannons Index) of communities are correlated to the year of soil deglaciation. Shannon Index values increase with sites deglaciated between 1 and 61 years ago; sites deglaciated between 61 and 78 years ago produce similar values, and those deglaciated 78 to 154 years ago show a further increase in diversity. Ground beetles and spiders are found at all sites, while ants and centipedes were associated with mature forest soils. On the glacier surface, pioneer species such as the wolf-spider Pardosa saturatior and the ground beetle Oreonebria castanea permanently inhabit the supraglacial detritus surviving on trophic resources. Wingless ground beetle species are associated with mature soils, especially those with high hydric stability. Open land species typical of primary succession are found in the pioneer and intermediate stages, while community assemblages found on older terrain are linked to forest vegetation structure and dynamics.

Heavy metals variations in some conifers in Valle d'Aosta (Western Italian Alps) from 1930 to 2000

Abstract The high mountain environment is very sensitive to the climatic and ecological variations that are registered in several natural archives as glaciers or plants. Trees, in particular, modify their growth, habitus, ring features and spatial distribution in relation with climate and environmental changes. Heavy metals variation in tree rings of Larix decidua have been determined to assess whether this arboreal species can be used as bio-geochemical tracers of heavy metal pollution to the alpine environment

Cupressus dupreziana: a dendroclimatic record for the middle-late Holocene in the central Sahara

Dendroclimatology of Cupressus dupreziana, the Tassili cypress, has been attempted on samples obtained from the door beams of the old cities of Ghat and Barkat located at the foot of the Tassili, where the cypress still lives. The tree rings of 20 samples were measured and dated by 24 AMS 14C dates. A mean ring-width chronology has thus been obtained, spanning, though discontinuously, 5220 to 100 14C BP (5990-65 cal. BP). As the tree-ring width in dry lands depends mainly on water availability, the mean ring-width chronology represents a detailed record of changes in rainfall on a decade scale for the middle and late Holocene of the central Sahara. It indicates main drought spells at 5200-5000 14C BP (5900-5760 cal. BP) and at 4350 BP (5120 cal. BP), followed by phases of enhanced precipitation and by the onset of extreme arid conditions at 1550 14C BP (1500 cal. BP).

Assessment and Selection of Geomorphosites and Trails in the Miage Glacier Area (Western Italian Alps)

Glacial environments are considered geomorphosites because they exhibit all of the features that characterise sites of geomorphological interest. The Miage Glacier, in particular, is the most important debris-covered glacier of the Italian Alps, and it has been extensively studied since the 18th century because of its scientific features. In this area, the geomorphological and geological attributes are evaluated at 11 sites that have been individuated along the three main touristic trails, which allow an exploration of the surroundings of the glacial tongue and its two main lobes. Using a methodology previously tested in a fluvial environment, single sites and trails are quantitatively assessed to determine the most suitable trail for educational purposes. Hazards that could potentially affect the trails are considered in terms of both risk education and final selection of the most suitable trails for the various possible user groups. The richness of scientific data in this area should increase its importance as a geomorphosite by increasing the educational value of the Miage Glacier and the Veny Valley.

Detecting Climatic Treelines in the Italian Alps: The Influence of Geomorphological Factors and Human Impacts

Treelines are widely studied worldwide in relation to climate changes because they are hypothesized to be sensitive climate proxies. However, forest treeline expansion toward higher altitudes may be influenced both by a warming climate and by other factors, such as surface morphology and, in the European Alps, the decline in alpine farming. Our results from five valleys in the inner and peripheral regions of the Alps show that present-day treeline altitudes mostly depend on anthropogenic and orographicgeomorphologic factors. Climatic treelines are limited to steep and inaccessible slopes, and occur at higher altitudes and farther from mountain peaks in the inner regions than in the peripheral regions of the mountain range. Looking for sites in which to study treeline responses to climate change, we recommend investigating the inner regions of the Alps where treelines are farther from human disturbances and from geomorphologic constraints, potentially resulting in freer upward shifts under warmer temperature conditions. We also found that, in the valleys selected, human disturbance is mainly concentrated about 165 m below non-climatic treelines, suggesting a homogeneous influence on treelines, regardless of geographic position.

DENDROGEOMORPHOLOGICAL ANALYSES ON EXPOSED ROOTS ALONG TWO MOUNTAIN HIKING TRAILS IN THE CENTRAL ITALIAN ALPS

ABSTRACT. Mountain landscapes show rapid evolution, especially at high altitudes, in response to current climate changes. In addition, the greater number of routes and trails made available and the increase in tourism have caused some impacts on mountain areas. Gradual soil erosion has been observed along some hiking trails, with the latter tending to deepen, and with stronger erosion where the trail cuts the slope. Where trails cross forested areas, trees can suffer root damage from foot trampling as roots become exposed. A dendrogeomorphological study was conducted on trees along two hiking trails in upper Valtellina (Italian Alps). On the first trail, in Valle dei Forni, European larches and stone pines, mostly with exposed roots, were sampled. A mean erosion rate of 2.7 mm/a, related to deepening of the footpath, was obtained, and various degrees of root growth disturbance along the trail were observed. In particular, the growth of many sampled roots shows an increase in ring width corresponding with the moment when root exposure occurred, followed, after 3–5 years, by rapid growth suppression. The exposure of many roots has taken place since the 1980s. No significant variations in stem growth were observed, even when there were exposed and damaged roots. Along the second trail, in Valle Alpisella, exposed roots of mountain pines were analysed. A mean erosion rate of 3.2–3.7 mm/a, related to the escarpments bordering the footpath, was obtained, while no significant changes were detected in root growth.

Landforms and geomorphosites ongoing changes: concepts and implications for geoheritage promotion.

Abstract The promotion of geological and geomorphological heritage is growing in importance for educational initiatives. The constantly increasing interest towards changing landforms due to changing climate conditions asks not only for improving the values of the cultural proposals but also for précising the subject of the discussion. Cultural trails and natural resources valorisation are more and more frequently based on the concept of geomorphosite, which is strictly linked to landform typology definitions. In sensitive areas, changing geomorphosites are considered of great interest as a typical response to changes in climate. In this paper, on the basis of recent research, we discuss the definitions of landforms and geomorphosites activity in relation to surface processes dynamics. In addition, we discuss the implications of geomorphological surface processes for geomorphosite evolution and degradation and their consequent impact on related valorisation activities. We indicate how both active and passive landforms, and therefore geomorphosites, are of great interest for scientific, educational and tourism purposes.

The influence of glacier surface processes on the short-term evolution of supraglacial tree vegetation: The case study of the Miage Glacier, Italian Alps

Supraglacial debris cover allows vegetation to colonize glacier surface, and whenever it is enough stable and thick, also shrubs and trees can germinate and grow. Supraglacial tree growth and distribution patterns on the glacier are closely connected with the debris-covered glacier dynamics and evolution. The aim of the research reported here was to evaluate the tree age and tree distribution patterns on the glacier tongue and the influence of ice-cliff backwasting, close to glacier terminus, on tree loss. We analysed the fragile and fast-changing environment that is present on the lower ablation sector of the Miage Glacier (Mont Blanc Massif, Italian Alps) where some ice cliffs are present and backwasting and downwasting phenomena occur. Tree features and short-term evolution were analysed with respect to glacier variations (mainly surface displacements and ice ablation) and geometry changes of the two most representative ice cliffs. The supraglacial trees’ life time resulted to be mainly controlled by glacier surface displacements and by the occurrence of backwasting and downwasting processes, whereas tree germination was associated with fine debris presence. These factors, controlling plants’ life and growth on the glacier, are an actual limit when supraglacial trees are analysed to reconstruct past environmental changes occurred on the glacier tongue. Moreover, we found that a large number of trees die under conditions of dominating backwasting inducing the loss of debris substrate (condition met especially on the northern glacier lobe). Instead, in the case of prevalence of downwasting (condition mainly observed on the southern glacier lobe), trees more easily survive and flow downvalley transported by the glacier flux.

Evaluating tourist perception of environmental changes as a contribution to managing natural resources in glacierized areas: a case study of the Forni glacier (Stelvio National Park, Italian Alps).

Climate change effects are noticeably evident above the timberline where glacier and permafrost processes and mass movements drive the surface evolution. In particular, the cryosphere shrinkage is deeply changing the features and characteristics of several glacierized mountain areas of the world, and these modifications can also affect the landscape perception of tourists and mountaineers. On the one hand glacier retreat is increasing the interest of tourists and visitors in areas witnessing clear climate change impacts; on the other hand cryosphere shrinkage can impact the touristic appeal of mountain territories which, diminishing their ice and snow coverage, are also losing part of their aesthetic value. Then, to promote glacierized areas in a changing climate and to prepare exhaustive and actual proposals for sustainable tourism, it is important to deepen our knowledge about landscape perception of tourists and mountaineers and their awareness of the ongoing environmental modifications. Here we present the results from a pilot study we performed in summer 2009 on a representative glacierized area of the Alps, the Forni Valley (Stelvio National Park, Lombardy, Italy), a valley shaped by Forni, the largest Italian valley glacier. During the 2009 summer season we asked tourists visiting the Forni Valley to complete a questionnaire. This study was aimed at both describing the features and characteristics of tourists and mountaineers visiting this Alpine zone in summer and evaluating their landscape perception and their ability to recognize climate change impacts and evidence. Our results suggest that the dissemination strategies in a natural protected area have to take into account not only the main landscape features but also the sites where the information will be given. In particular considering the peculiarities of the huts located in the area, such as their different accessibility and the fact that they are included or not in a mountaineering network like that of the Italian Alpine Club. Both these factors can influence the kind of visitors to the area, thus requiring different dissemination strategies. Moreover, differences in the viewpoints from where visitors could watch and understand landscape also have to be considered. Next, in a protected area where climate change effects are evident, the dissemination strategies should be developed in close cooperation with scientists who are analyzing the area and with the support of periodic interviews which could be very useful to evaluate the effectiveness of the applied dissemination methods. Last but not least, the questionnaire should be standardized and distributed in several protected areas, thus permitting useful comparisons and the identification of common solutions for sharing in a friendly way scientific knowledge about climate change and its effects on the environment and the landscape.

The role of Ecological Value in Geomorphosite assessment for the Debris-Covered Miage Glacier (Western Italian Alps) based on a review of 2.5 centuries of scientific study

Ecological attributes of geomorphosites play a significant role as one of the characteristic components of their scientific value, hence influencing their global value. Ecological attributes can, however, act independently and inform other attributes which characterise scientific and additional values and the sites potential for use. Within the framework of active geomorphosites, environmental changes and recent dynamics can be reconstructed through tree-ring analysis. Glacial geomorphosites are one of the most significant examples of this biotic–abiotic relationship. Among glacial geomorphosites, debris-covered glaciers represent key sites at which to evaluate an ecological attribute. The Miage Glacier, the most representative Italian debris-covered glacier, is an important site for multidisciplinary scientific research, enhancing its global value as a complex geomorphosite. The Miage Glacier has been selected as a study site, firstly to characterise the evolution of scientific research across the last 250 years and then to quantify the ecological support role (ESR) and its influence on the other attributes. The ESR’s importance in assessing global geomorphosite values was estimated by studying its variation and the variation of the related attributes as a consequence of an increase in scientific knowledge over time. The ESR variation displays a positive effect on scientific value, in particular, and generates more differentiation between defined sites and visitor trails, thus influencing site selection.