Changes in the diversity of the Paleogene greenhouse vegetation at the southern edge of the proto-North Sea

The Paleogene succession of the Helmstedt Lignite Mining District in Northern Germany includes records of coastal peat mires from the latest Paleocene to the middle Eocene. Due to an interaction between changes in sea level, salt withdrawal in the subsurface and climate-related changes in runoff from the hinterland the area was subject to frequent changes between marine and terrestrial conditions, including peat formation. In an almost continuous section, the effects of long-term changes and short-term perturbations of the climate on the diversity and composition of plant communities can be traced by using pollen and spores as proxies. High-resolution C-isotope analyses allowed for precisely locating important short- and long-term climate events within the lower Eocene greenhouse, such as the Paleocene Eocene Thermal Maximum (PETM) and the Early Eocene Climatic Optimum (EECO). Here we present high-resolution palynological data from the lower Eocene Schöningen Formation at Schöningen to compare the wetland vegetation before, during and after these events. The focus is on the identification of short-term pulses versus long-term sustainable changes in composition and diversity of the vegetation. However, a climatic influence and the corresponding response of the ecosystems cannot simply be revealed from the microflora as documented in the studied succession. When interpreting the palynomorph record it is necessary to distinguish between changes in the vegetation that were controlled by climate or those controlled by other factors such as, for example, natural succession due to peat aggradation.