Changes in Eocene plant diversity and composition of the vegetation: the lacustrine archive of Messel (Germany)

Based on high resolution palynological analysis of 680 samples from a core, short-term changes in plant diversity and floristic composition within the Paleogene greenhouse have been detected in the lacustrine succession of a Lower to Middle Eocene maar lake at Messel (Federal State of Hesse, Germany). The microfloristic data show that taxonomic diversity increased rapidly within some decades during recolonization of a volcanically devastated area around the lake. With the establishment of a climax vegetation at the end of recolonization the maximum in palynological diversity was reached in the crater area. During the following 640 Kyr the composition of the palynospectrum changed only gradually. However, different richness and evenness estimations show that alpha and gamma diversity decreased up to 35% which can be related to the establishment of an equilibrium stage within the climax vegetation that led to the dominance of an assemblage of self-replacing species. Nevertheless, time ser...