Nelle regioni alpine il riposo vegetativo, le basse temperature e la diffusa copertura nevosa suggeriscono che l’attività biologica del suolo sia concentrata soltanto durante la stagione estiva. In realtà, i suoli ricoperti da un consistente manto nevoso sono isolati dalla rigida temperatura dell’aria e possono non gelare nel corso dell’inverno. L’innalzamento del limite delle nevicate e la riduzione della permanenza della neve al suolo in seguito al riscaldamento globale può però determinare una riduzione dell’effetto isolante del manto nevoso, esponendo i suoli del piano montano (1100-1400 m s.l.m.) a temperature più basse e ad una maggiore frequenza di cicli gelo/disgelo che potrebbero alterare la dinamica della sostanza organica e la disponibilità di nutrienti nel suolo, con potenziali effetti sulle specie vegetali ed animali.

SNOW DEPTH MANIPULATION AND ITS INFLUENCE ON SOIL TEMPERATURE AND NUTRIENT DYNAMICS IN NORTH WEST ITALY (AOSTA VALLEY)

Snow cover and duration play a key role in a number of environmental and socio-economic systems in mountain regions. As an indicator of climatic change, snow is an interesting variable, because is dependent not only on temperature, but also on precipitation.
Several studies in the Alps reported that snow amount and duration has been sensitive to changes in climate over the last 15 years at altitudes below 1500 m asl. This is consistent with the rise in average snowline projected under a warmer global climate.
In this study the snow depth was manipulated by removing snow for one winter, simulating a year with little snow. We established two sites, each with two paired plots, at the Riserva Naturale Mont Mars, in Fontainemore (Valle d’Aosta, North West Italy), and instrumented all four plots with soil thermistors. For one winter we removed snow from the designated treatment plots. Snow in the reference plots was undisturbed. Snow samples have been collected during the winter for the determination of the chemical content.
The data show that winters with low snowfall, simulated by snow removal, will result in increased soil freezing, with implications for changes in soil biogeochemical processes