Holocene vegetation history and human impact in the eastern Italian Alps: a multi-proxy study on the Coltrondo peat bog, Comelico Superiore, Italy

The present study aims to reconstruct vegetation development, climate changes and human impact using an ombrotrophic peat core from the Coltrondo bog in the eastern Italian Alps. Evidence from pollen, micro-charcoal, major and trace elements, and lead isotopes from this 7,900 years old peat deposit has been combined, and several climatic oscillations and phases of human impact detected. In particular, human presence was recorded in this area of the Alps from about 650 cal bc, with periods of increased activity at the end of the Middle Ages and also at the end of the 19th century, as evidenced by both human-related pollen and the increase in micro-charcoal particles. The enrichment factor of lead (EFPb) increased since the Roman period and the Middle Ages, suggesting mainly mining activities, whereas the advent of industrialization in the 20th century is marked by the highest EFPb values in the whole core. The EFPb data are strongly supported by the 206Pb/207Pb values and these are in general agreement with the historical information available. Therefore, the multi-proxy approach used here has allowed detection of climatic events and human impact patterns in the Comelico area starting from the Iron Age, giving new insights into the palaeoecology as well as the course of the interaction among humans, climate and ecosystems in this part of the eastern Italian Alps.