LATE-GLACIAL AND HOLOCENE FIRE AND VEGETATION HISTORY FROM LAGO DI MEZZANO, CENTRAL ITALY

Lago di Mezzano (Lazio, Central Italy, 42°37`N, 11°56`E, 452 m a.s.l.) is an extant maar lake located 100 km NW of Rome lying inside the caldera of the Latera volcano. Charcoal, pollen, magnetic susceptipility, as well as geochemical proxies have been used to define the vegetation, climate, and human-induced changes occurred at Lago di Mezzano in the last 15,000 cal. years. A sound chronology of the whole sediment record spanning the last 30,000 years was proposed on the basis of varve thickness measurements, interpolated sedimentation rates, AMS radiocarbon dates, and tephra layers study. In the Mediterranean basin, in regions where man has been present since the Palaeolithic age, and whose impact on the environment became stronger and stronger through the millennia, the difficulty exists of singling out the changes induced by man on vegetation. As Mediterranean Italy is a sensitive region from a climatic perspective and as many prehistoric sites are found in the surroundings of Lago di Mezzano, a multi-disciplinary approach in the study of its sediments turned out a precious tool to disentangle human impact from natural trends. Early people are thought to have modified flora and vegetation in a variety of ways: introducing or favouring edible plants, opening up woods for animal husbandry and at the same time using natural resources such as wood for cooking, heating, building, or mining and producing metals. The use of fire in forest clearance deserves to be investigated. Each of these man-induced ways of environmental change produced a characteristic vegetation pattern, whose traces were found in the pollen and micro-charcoal record. Natural important fires occurred at the beginning of the Holocene interglacial until 10000 cal. years BP, in a period in which the climate was rather unstable and human presence is hardly detected. In the long period between 10000 to 4000 cal. years BP only a number of sporadic and isolated fires occurred. The interfingering of climate and human impact effects on the environment turned out particularly clear during the Bronze age period, from about 4100 to about 2900 cal years BP. Fires played an important role in modifying the landscape also during the Roman and the Middle Ages periods, as well as in the last centuries, when a strong human pressure on the environment is pointed out.