Humus forms as a synthetic parameter for ecological investigations. Some examples in the Ligurian Alps (North-Western Italy)

In the Ligurian Alps, a wide range of site conditions that influence soil development and may affect humus variability is present. In this work, we wanted to evaluate the potentialities of humus forms as a synthetic indicator of both chemical properties of the humic episola and site conditions in the upper Tanaro Valley (NW Italy). Vegetation affected the C/N ratio of the least transformed organic horizons, but the effect disappeared in mineral ones, where soil pH was related to the parent material. All terrestrial humus forms were found in the area and their distribution well reflected the interactions between vegetation, lithology, elevation that shaped soil properties and affected the degradability of litter and its actual degradation by microorganisms and soil fauna. Humus forms were thus able to capture the ecological conditions, integrating the information provided by soil classifications

Root morphology and biomechanical characteristics of high altitude alpine plant species and their potential application in soil stabilization

Glacial forefields host young, poorly developed soils with highly unstable environmental conditions. Root system contribution to soil stabilization is a well-known phenomenon. Identifying the functional traits and root morphology of pioneer vegetation that establish on forefields can provide information useful in the practical application of plants in land restoration of high altitude mountain sites.This study aims to gather information on the root morphology and biomechanical characteristics of the 10 most dominant pioneer plant species of the forefield of Lys Glacier (NW Italian Alps).X-ray Computed Tomography (X-ray CT) was used to visualize and quantify non-destructively the root architecture of the studied species. Samples were cored directly from the forefield. Data on root traits such as total root length, rooting depth, root diameter, root length density and number of roots in relation to diameter classes as well as plant height were determined and compared between species. Roots were also tested for their tensile strength resistance.X-ray CT technology allowed us to visualize the 3D root architecture of species intact in their natural soil system. X-ray CT technology provided a visual representation of root-soil interface and information on the exact position, orientation and elongation of the root system in the soil core. Root architecture showed high variability among the studied species. For all species the majority of roots consisted of roots smaller than 0.5. mm in diameter. There were also considerable differences found in root diameter and total root length although these were not statistically significant. However, significant differences were found in rooting depth, root length density, plant height and root tensile strength between species and life forms (dwarf shrub, forb, graminoid). In all cases, root tensile strength decreased with increasing root diameter. The highest tensile strength was recorded for graminoids such as Luzula spicata (L.) DC. and Poa laxa Haenke and the lowest for Epilobium fleischeri Hochst.The differences in root properties among the studied species highlight the diverse adaptive and survival strategies plants employ to establish on and thrive in the harsh and unstable soil conditions of a glacier forefield. The data determined in this study could provide a significant contribution to a database that allow those who are working in land restoration and preservation of high altitude mountain sites to employ native species in a more efficient, effective and informed manner