Climate changes and first evidence of human impact in the southern Tyrrhenian coast during the last climatic cycle: regional versus local vegetation signal

Charcoal remains collected from the archaeological sites of Serratura and Cala caves, on the Cilento coast (southern Tyrrhenian Sea, Italy), provide local information about the vegetation cover during part of the Last Glacial Period, the Late Glacial and the early-middle Holocene. Mixed deciduous forests and mountain pines characterise the landscape until the end of the Last Glacial Period. The principal component analysis applied to the matrix of species ecological indices (Ellemberg-Landolt) allowed Pinus charcoals to be most probably ascribed to the species P. nigra. Charcoal analysis shows that pine disappeared at the beginning of the Holocene while the outcoming explosion of evergreen shrubs occurred in the middle Holocene together with the first evidence of Vitis and Olea. The vegetation data obtained from charcoals are coherent with the glacial landscape image reconstructed through pollen analysis in the Salerno Gulf-Sele Plain area (Russo Ermolli and Di Pasquale, 2002) where deciduous oaks are stable around 10% (Pinus excluded) during the entire LGP. AP values are always over 30%, except for the period around 29 kyr BP, where tree pollen drastically fall to ~10%. This features, together with the presence of Abies (up to 10%) and of other deciduous taxa, such as Carpinus, Ulmus and Alnus, suggests phases of milder climatic conditions even during the LGM. A recent quantitative climatic reconstruction based on the Salerno Gulf core (Di Donato et al., 2008) shows a cold and arid phase, from 34 to 27 kyr BP, where the lowest values of TANN (7°C), TJUL (20°C) and PANN (400 mm/y) are pointed out, followed by a long period of mild climate, centred around 25 kyr BP, characterised by high temperature (TANN=14°C) and precipitation values (900 mm/yr). This lanscape recontruction seems to disagree with the most common Pleniglacial image obtained from pollen data in central-southern Italy (Allen et al., 2000; ) where the evidence of steppe or wooded-steppe environments most probably reflects the more continental and higher position of those sites.The relative stability of vegetation cover highlighted by charcoal data from the Serratura cave suggests that the climatic variability of the LGP slightly affected the coastal areas of southern Italy. The constant presence of deciduous Quercus in the Salerno pollen record could, thus, be the consequence of the major role played by coastal pollen sources in respect to the total pollen content. Correlation between charcoal and pollen not only allowed the mesophilous forest to be located in the coastal sector of southern Italy, but suggested that the last glacial refugia of deciduous Quercus were located at low altitudes and close to the sea.