Papers by Michele D'amico
Ancient soils (pre-Holocenic paleosols and vetusols) are uncommon on the Alps, because of the ext... more Ancient soils (pre-Holocenic paleosols and vetusols) are uncommon on the Alps, because of the extensive Pleistocenic glaciations which erased most of the previously existing soils, the slope steepness and climatic conditions favoring soil erosion. However, in few sites, particularly in the outermost sections of the Alpine range, Pleistocene glaciers covered only small and scattered surfaces because of the low altitude reached in the basins, and ancient soils could be preserved for long periods of time on particularly stable surfaces. We described and sampled soils on 11 stable surfaces in the Upper Tanaro valley, Ligurian Alps (Southwestern Piemonte, Italy). The sampling sites were characterized by low steepness and elevation between 600 to 1600 m, under present day lower montane Castanea sativa/Ostrya carpinifolia forests, montane Fagus sylvatica and Pinus uncinata forests or montane heath/grazed grassland, on different substrata. In particular, we sampled soils developed on dolomi...
Organic matter (OM) is the most important factor affecting soil fertility and nutrient recycling ... more Organic matter (OM) is the most important factor affecting soil fertility and nutrient recycling in forest soils. However, the amounts of organic C stored in soils depend on the dynamic equilibrium between emissions and retentions, which is specific of the different OM pools. A key element for assessing C dynamics in forest soils is the identification of the links between soil OM pools and stabilization mechanisms. OM may in fact be stabilized against decomposition thanks to its inherent recalcitrance and to organo-mineral associations, including coulombic (H-bonding, anion and cation exchange, ligand exchange, cation bridges) and non-coulombic interactions. The purpose of this study was the assessment of the main mechanisms of SOM stabilization in forest soils as a function of the characteristics of the mineral phase and of litter quality. In a mountain area of the Ligurian Alps (NW Italy), we selected 21 soil profiles taking into account both lithology and forest cover. Soil chemi...
Organic matter (OM) occurs in soils in various pools showing different resistance degrees against... more Organic matter (OM) occurs in soils in various pools showing different resistance degrees against degradation as a consequence of the mechanisms governing their stabilization. In Podzols, OM is mainly stabilised by association with the mineral phase, and with the ongoing of podzolisation an enhancement of metal-organic interactions (Fe-and Al-OM) occurs. Although OM typically has a very complex structure, in which the abundant microporosity may reach dimensions even <2 nm, when stabilized by mineral associations OM structure can change. A larger ultramicroporosity (<0.7 nm) than the labile pool is expected, reflecting the higher rigidity/condensation of OM structure given by association with metals. In well-developed Podzols, a metal-rich cemented horizon, called ortstein (Bsm or Bhsm), may form in addition to non-cemented Bs or Bhs ones. In these cemented horizons OM ultramicroporosity may be enhanced. To investigate OM structure the gas adsorption technique is particularly s...
Because of extensive Pleistocenic glaciations which erased most of the previously existing soils,... more Because of extensive Pleistocenic glaciations which erased most of the previously existing soils, slope steepness and climatic conditions favoring soil erosion, most soils observed on the Alps (and in other mid-latitude mountain ranges) developed only during the Holocene. However, in few sites, particularly in the outermost sections of the Alpine range, Pleistocene glaciers covered only small and scattered surfaces because of the low altitude reached in the basins, and ancient soils could be preserved for long periods of time on particularly stable surfaces. In some cases, these soils retain good memories of past periglacial activity. We described and sampled soils on stable surfaces in the Upper Tanaro valley, Ligurian Alps (Southwestern Piemonte, Italy). The sampling sites were between 600 to 1600 m of altitude, under present day lower montane Castanea sativa/Ostrya carpinifolia forests, montane Fagus sylvatica and Pinus uncinata forests or montane heath/grazed grassland, on diffe...
Soils store three times as much organic carbon (OC) as is found in living plants, and most forest... more Soils store three times as much organic carbon (OC) as is found in living plants, and most forest soils are active CO 2 sinks at present. With climate change however, the capacity of soils to preserve OC against degradation will highly depend on the presence of stabilized organic matter (OM) pools. Podzols are among the most characteristic soils in forest ecosystems and their formation is linked to OM movements through the profile and the following stabilization by metal-organic interactions (Fe-and Al-OM) in deeper soil horizons. Recently, we found that the type of metal-organic association changes with increasing intensity of podzolisation and that the variations can be followed by evaluating specific surface area (SSA) by N 2 adsorption. We hypothesised that at later stages of podzolisation stable OM is more tightly bound to metals, hence more rigid and poorer in N 2-accessible pores. In well-developed Podzols, cemented metal-rich horizons (ortsteins i.e. Bsm or Bhsm) may form in...
Ancient soils (pre-Holocene paleosols and vetusols) are uncommon on the Alps, because of the exte... more Ancient soils (pre-Holocene paleosols and vetusols) are uncommon on the Alps, because of the extensive Pleistocene glaciations which erased most of the previously existing soils, the slope steepness and climatic conditions favoring soil erosion. However, in few sites, particularly in the outermost sections of the Alpine range, Pleistocene glaciers covered only small and scattered surfaces because of the low altitude reached in the basins, and ancient soils could be preserved for long periods of time on particularly stable surfaces. We described and sampled soils on some of these stable surfaces in the Upper Tanaro valley, Ligurian Alps (Southwestern Piemonte, Italy). The sampling sites were characterized by low steepness and elevation between 800 to 1600 m, under present day montane Castanea sativa, Fagus sylvatica and Pinus uncinata forests or grazed heath/grassland, on quartzite or quartz-rich metamorphic rhiolites or shales. Podzolic soils are widespread in the area on such subst...
Climate change has huge impacts on mountain ecosystems. One visible effect is glacier retreat, wh... more Climate change has huge impacts on mountain ecosystems. One visible effect is glacier retreat, which has continued with only few interruptions since the end of the Little Ice Age (LIA), around the mid-nineteenth century. The released surfaces in the proglacial areas (glacier forefields) offer the opportunity to observe the development of soil properties and ecosystem dynamics: habitats characterized by different ages coexist over short distances, reducing the effect of other geographical and climatic factors. It is thus possible to observe how the time factor influences pedogenic and ecosystem processes, obtaining chronosequences.
The climatic influence on soil properties is important on ophiolites: large quantities of toxic m... more The climatic influence on soil properties is important on ophiolites: large quantities of toxic metals can be released, mobilized or immobilized in relation with different climates. A different leaching intensity also influences the available Ca/Mg ratio, an important factor in serpentine ecology. In the Aosta Valley, north-western Italian Alps, different climates are found at short distances, due to specific orography. Mediterranean air masses increase rainfall throughout the year in the south-eastern sector: in Champorcher (1427 m a.s.l.), the average rainfall is 1185mm/y; 83 mm normally fall in July (the driest summer month). Rain-shadow effects influence the drier central sector: in Torgnon (1500 m a.s.l.), normally, precipitation is 620 mm/y; 40 mm fall in summer months (inner-alpine climate). The temperature decrease (0.65°C/100m) and the precipitation increase with elevation are further sources of variability. We compared the active pedogenetic processes the chemical properti...
Mountain ecosystems are highly vulnerable to flash flood phenomena, which can result in sudden so... more Mountain ecosystems are highly vulnerable to flash flood phenomena, which can result in sudden soil water saturation and surface erosion. Saturated soils are vulnerable to solifluction and liquefaction, depending on soil plastic properties. Surface erosion and mass movements create serious hazards for the population and the infrastructures: the recognition and mapping of areas characterized by different vulnerability to erosion processes are of primary importance in order to properly manage the land use and the hydro-geological hazards. The study area is the whole Val d’Aosta region, characterized by a wide range of geological substrates, vegetation types, altitude variations and pedoclimates (from perudic in south-east and at high altitude to xeric-ustic in the intra-alpine central valley). All genetic horizons from 150 soil profiles have been described and analyzed (standard chemical analysis and Atterberg limits), in order to understand how pedogenic processes influence soil plas...
Climate changes have huge impacts on alpine ecosystems. One of the most visible effects is glacia... more Climate changes have huge impacts on alpine ecosystems. One of the most visible effects is glacial retreat since the end of the Little Ice Age (LIA: 190-190 years ago), which caused the exposure of previously glaciated surfaces. These surfaces are open-air laboratories, verifying theories regarding ecosystem and soil development. In order to increase our knowledge on the effect of time and vegetation primary succession on soil development in proglacial areas, we sampled soils and surveyed plant communities on stable points on the proglacial areas of the Lys and Verra Grande glaciers, in the Italian north-western Alps (Valle d'Aosta). Sampling sites were located on dated sites (6-260 years), on the basis of literature or historical photographs). Glacial till is attacked by weathering processes immediately after deposition and stabilization, such as loss of soluble compounds, acidification, primary mineral weathering. The speed of these processes are largely increased after the es...
Climate changes have huge impacts on alpine ecosystems. One of the most visible effects is glacia... more Climate changes have huge impacts on alpine ecosystems. One of the most visible effects is glacial retreat, which caused the exposure of previously glaciated surfacessince the end of the Little Ice Age (190-190 years ago).These surfaces are open-air laboratories, verifying theories regarding ecosystem and soil development. In order to increase our knowledge on the effect of vegetation andsubstrate on pedogenic processes and rates, we sampled soils and surveyed plant communities in the proglacial areas of the Lys and Verra Grande glaciers, in the Italian north-western Alps (Valle d’Aosta). Sampling sites were located on dated sites, based on literature or historical images. Chronofunctions of organic carbon, nutrients and spodic properties were calculated, based on the results of standard analytical data of soil samples, derived from all genetic horizons. Glacial till is attacked by weathering processes immediately after deposition and stabilization, such as loss of soluble compounds...
1 : Introduction Les sols sur matériaux ophiolitiques sont normalement riches en bases (surtout M... more 1 : Introduction Les sols sur matériaux ophiolitiques sont normalement riches en bases (surtout Mg) et présentent une réaction proche de la neutralité. Ces caractéristiques ralentissent le processus de la podzolisation, même s’il y a les conditions environnementales favorables. Des nombreuses études montrent l’impossibilité du développement de véritables PODZOSOLS sur ces substrats, grâce aux pH élevés, au complexe adsorbant saturé en bases et à l’absence de migration des complexes organo-métalliques. Dans le Parc Naturel du Mont Avic (Vallée d’Aoste, Italie), on a étudié des sols développés sous forêt subalpine et sur substrats rocheux, couverts par éboulis de gravité et dépôts morainiques, tous constitués de roches mafiques et ultramafiques. Il s’agit de serpentinites (surtout du type antigorite), associées avec chloritoschistes, métagabbros, prasinites et amphibolites. Le bassin orographique n’a pas reçu apports glaciaux ou lithologiques de l'extérieur pendant ou après la der...
Soils on ultramafic materials are usually rich in Mg, Fe and heavy metals (particularly Ni, Cr, M... more Soils on ultramafic materials are usually rich in Mg, Fe and heavy metals (particularly Ni, Cr, Mn, Co). These chemical properties could cause toxicity effects on biological communities. Metal fractionation shows the soil phases to which metals are associated (exchangeable, associated with organic matter, with amorphous or crystalline Fe or Mn oxides, in the crystal structure of primary minerals), and thus it is strictly related with metal mobilization and bioavailability. Ni, Cr, Mn, Co and Fe fractionations (6 fractions, analysed by a selective sequential extraction technique) were analysed in 6 subalpine and in 17 alpine soils (i.e., respectively under coniferous forest or above the present-day treeline) in the ophiolitic area of Mont Avic Natural Park (Valle d'Aosta, Italian Alps), on soils formed from metal-rich serpentinite or from metal-poor mafic rocks and calcschists. The results show a tight relationship between vegetation, soil forming processes, metal fractionation ...
Uploads
Papers by Michele D'amico
97 soil pits (associated with phytosociological surveys) were analyzed above the treeline in Mont Avic Natural Park (Val d’Aosta, north-western Italy). The aim was to recognize pedogenic processes, mobility and bioavailability of metals and nutrients, to statistically identify edaphic properties influencing vegetation and possible stress symptoms on microbial and arthropodal communities.
On serpentinite, meta-gabbros and calcschists, in cold and wet high-altitude climates (annual temperatures below 2°C and rainfall below 1300mm/y), soils are acidic, with pH values increasing with altitude and cryogenic or erosive disturbances. Cryoturbation, erosion and deposition “rejuvenate” soils by adding unweathered material into surface horizons: the soil chemistry depends on substrate, and metal concentration is increased in biologically-active horizons on serpentinite. Despite the weak soil development, metal speciation shows a strong mobilization and bioavailability, caused by waterlogging at snowmelt and acidity.
On serpentinite, high bioavailable Ni is related with the absence of some common acidophilous species, despite the low pH values, and with the presence of serpentine-endemic species. Ca/Mg ratios, nutrients and pH values are not statistically significant.
Bioavailable metals don’t significantly influence micro-arthropod communities. Microbial activity and stress indices are not related either with substrate or metal content.