PLANT INTERCHANGE BETWEEN EUROPE AND NORTH AMERICA ACROSS THE PALEOCENE/EOCENE TRANSITION

The impacts of the Paleocene-Eocene Thermal Maximum (PETM) on mammal communities and oceanic plankton have been well documented. In contrast, the effect on plants of PETM climate change is less known. We have assembled an extensive dataset of Late Paleocene (Thanetian) and Early Eocene (Ypresian) palynofloras from Europe and North America in order to better document and understand the change in vegetation type and geographic range changes of plants between and within these two regions. Our raw dataset includes approximately 1000 taxa from c. 60 localities from the North America and Europe. The dataset demonstrates that there are twelve immigrants from Europe to North America, but the exchange pattern is one-sided because there is little, if any, interchange from North America into Europe. North American immigrants include Brosipollis sp., Compositoipollenites sp., Intratriporopollenites instructus, Intratriporopollenites ceciliensis, Platycaryapollenites anticyclus, Platycaryapollenites platycaroides, Platycaryapollenites swasticoidus, Milfordia hungarica, Anacolosidites sp., Interpollis microsuplingensis, Trudopollis subhercynicus, and Dicolpopollis sp. Those represent a diverse range of plants and ecologies. Taxa new in the early Eocene of Europe, but present in the Paleocene of North America include Bombacacidites, Porocolpopollenites ollivierae, and Proxapertites. Again, the range of plants includes different families with differing ecological requirements.

Considering the size of the dataset and the number of morphotaxa identified, the Paleocene/Eocene boundary is associated with very little exchange between continents with little immigration into Europe that can be related to the PETM. The results from this dataset confirm earlier work that establishes independence of mammalian immigration from plants.