A vegetation rich in mega- and mega-mesothermic elements, organized in altitudinal belts, comparable to that which grows in subtropical climate regions today has been inferred for the Miocene in Europe. This is interpreted as corresponding to a subtropical to warm-temperate climate during the Miocene and is confirmed by the estimation of climatic parameters through the application of the Climatic Transfer Function that provide values of around 15-21ºC.

The Late Burdigalian and Langhian are characterized by a maximum in the percentage of megathermic and mega-mesothermic taxa. This is interpreted here as related to the response of the vegetation to the Miocene climatic optimum (MCO). This event is recognized globally, and is characterized by the lowest values in the δ18O isotopic curve. It is characterized, in the middle European latitudes, by the abundance of Avicennia in the pollen spectra, developing an impoverished mangrove on the coasts, and estimated temperatures around 19-21ºC.

Later, in the Serravallian, a strong decrease in mega- and mega-mesothermic plants and the disappearance of Avicennia in southern France and northeastern Spain took place, and, as a consequence, a progressive decrease in diversity occurred. At the same time, the percentage of mesothermic plants increased. This floristic degradation is interpreted as a consequence of the progressive climatic cooling that took place during the Serravallian, produced mainly by an Antarctic glaciation. The climatic estimations corroborate this cooling to a decrease in temperature, with mean values of about 6.7ºC in Switzerland or 3ºC in Central Europe. This cooling is globally known as "Monterey cooling event,” which corresponds to the isotopic curves as a strong increase in the values of the δ18O.

High-resolution pollen analysis allowed us to distinguish repetitive changes in the vegetation characterised by the alternation of thermophilous taxa with altitudinal taxa. The astronomic tuning of these vegetation changes to the eccentricity and insolation time series of La93(1,1) solution, in the case of the Tengelic-2 borehole, is rather consistent. Spectral analysis of pollen data reveals the influence of astronomical climatic changes on the evolution of the studied vegetation. Obliquity and eccentricity are dominant while precession is poorly registered.

The Middle Miocene pollen records allow us to document the presence of a latitudinal climatic gradient from southern Spain to Switzerland. The results demonstrate that, in a vast European subtropical frame, some taxa as Calligonum, Neurada, Nitraria, Prosopis and Lygeum, linked to a very dry climate, were already present during the middle Miocene in the northwestern Mediterranean area. These subdesertic taxa associated in the pollen spectra to Avicennia, populating the coastal area, characterized the lowlands. The gradual disappearance of these subdesertic elements and the progressive increase in mega-mesothermic plant taxa with higher water requirements going northward, from the very South of Spain to Switzerland, is interpreted as a strong latitudinal gradient in precipitation. Consequently, four different types of pollen assemblages and four consistent climatic domains have been differentiated. The presence of similar thermophilous taxa in the pollen spectra from all the localities shows that the latitudinal gradient in terms of temperature was not as large as it is today, with an estimated value of 0.43º C per degree of latitude.