Geological landscape and soil diversity as proxies for land-use change in marginal communities of the Western Italian Alps

In landscapes as complex as mountain ranges, “marginal” territories where human activity is limited represent a primary source of information for the reconstruction of environmental change and human-landscape interactions, especially in areas as densely populated as the Alps where human impact is often too widespread. Within the marginal area of the San Grato Valley (Aosta Valley, NW Italy) ongoing human presence started at the arrival of German-speaking Walser populations in the 13th-14th Century, up until today. Within the framework of the Interreg ALCOTRA (Italy–France) project “DAHU”, we applied a multiscale approach integrating geoarchaeological proxies with evidence from archaeology, forest ecology, archaeology, history, paleoecology, dendrochronology, and wood anatomy, to provide insights on the interplay between Walser communities and landscape factors since the Middle Ages. Preliminary data show how topography and geomorphological processes, especially past glacial and slope dynamics, strongly dictate the extent of land use and settlement distribution in time. Soils also documented the human imprint on the landscape, recording both climatic oscillations and land-use changes. Human activity in the San Grato Valley likely began well before the arrival of the Walser people, opening new perspectives on the timing and extent of human presence in these high mountain valleys.