Holocene vegetation development and human impact in the central Alps: the "Pian Venezia" palaeobotanical record (Trento, Italy)

Abstract

The preliminary results of palaeobotanical analyses carried out on the peat-bog of Pian Venezia at the altitude of 2270 m a.s.l. in Val di Peio (Eastern Italian Alps), are presented in this paper. The aim of this work is the reconstruction of the vegetation development in a high altitude environment. Six radiocarbon dates provide a time control between 9,2 ka BP and the present time. The peat accumulation started during the Preboreal and is assumed to have been continuous up to the present. The Pian Venezia pollen succession illustrates the main Holocene vegetational events. In the late Preboreal an alpine meadow with shrubs grew close to the peat-bog, whereas other areas were still with no vegetation. The first Picea pollen grains are recorded by a continuous curve at about 8.9 ka BP; the Picea curve shows a sharp increase at 8.7 ka BP, when this tree was present in the upper Val di Peio. During the middle and late Atlantic the presence of macroremains of Pinus cembra and Larix (needles, stomata and seeds) in the peat indicates that the forest line surrounded the bog. Fagus and Abies are recorded at about 6.5 and 6-5.5 ka BP, respectively. Two phases of human impact were recorded; the first, dating to 4 - 3 ka BP, may be attributed to the Late Neolithic; the second, which begun at about 2,2 ka BP, can be attributed to the Roman period. During this latter phase, the occurrence of spores of Podospora and Sporormiella, which are coprophilous fungi, suggests that at that time the Pian Venezia plain was used as a pasture.