No abstract

No abstract

No abstract

Loess in Northern Italy has been usually considered deposited during the MIS 4-2 period, which corresponds to the last Pleistocene glacial cycle. In particular, no absolute dating evidenced loess depositions older than ca. 89 ka. We investigated two strongly rubified soil profiles in the southern margin of the Alpine range in Lombardy to prove their aeolian origin and age of formation. MethodsWe analysed the granulometry of all genetic horizons of these strongly rubified soils and a total of 8 samples were collected for luminescence dating purpose. ResultsMost of the analysed soil horizons were dominated by silt and were characterized by the s-shaped granulometric curve, typical of loess materials. A particularly high clay content evidenced a strong weathering degree. A deep horizon was particularly clay-rich and it was interpreted as a typical Terra-Rossa horizon. Luminescence dates increased with depth, reaching 122 ka for the deepest loess layer and 453 ka (minimum age) for the Terra-Rossa horizon. ConclusionsThe deepest observed loess layer represents the oldest quantitatively dated aeolian deposition in Northern Italy up to now.

Invasive alien plants may profoundly transform ecosystems over wide areas. The study aimed to assess how the invader Reynoutria bohemica could transform ecosystem components of a native riparian forest in Northern Italy, after about 20 years of invasion. We selected 20 forest sites where we set up two 1 Â 1 m plots, one in an invaded and one in a non-invaded patch. Subsequently, we surveyed the properties of litter and mineral soil, soil biological quality (QBS-ar), diversity of plant and microarthropod communities and light intensity at the ground level. To determine if the invader affected the quality of herb layer, we selected the native herb Allium ursinum as the indicator species of good quality forest stand and measured its traits in the paired plots. Following the application of linear mixed effects models, the invaded and non-invaded plots showed differences in soil characteristics and plant community: the thickness of the organic horizon, soil C:N and available P were higher in invaded plots, whereas diversity, light intensity, Allium ursinum abundance and its vegetative vigour were found to be lower. Microarthropod communities and QBS-ar were modestly influenced by R. bohemica. Redundancy analysis of plant community composition indicated that soil C:N and plant richness were the variables most linked to species invasion. This study highlights the ability of R. bohemica to transform certain ecosystem components in native riparian forests, after just a few decades since its first invasion, thereby underlining the need to implement measures to control its spread.