XVI International Botanical Congess

The quantification of the Pliocene (5.32 to 1.77 Ma) climate from pollen data required a new method. The first step of this method was to determine the present-day distribution of some selected marker-taxa of the Mediterranean Pliocene (subtropical and Saharian plants) and the second step was to define climatic amplitudes of various taxa on the basis of several thousand modern pollen spectra. This new method has been applied to many Pliocene pollen sequences around the West Mediterranean area. The results show that during the Pliocene the latitudinal gradient was already existing, both for temperatures and precipitation, and that the climate was warm and humid in the North Mediterranean area (1 to 4°C and 400 to 700 mm higher than today), but warm and dry in the South Mediterranean area (equal or 5°C higher and drier or equal than today).