Extinction and Recovery in Terrestrial Ecosystems across the Permian-Triassic Boundary in South Africa

Smithsonian Institution, Washington DC

Investigators

Abstract

PROJECT ABSTRACT EXTINCTION AND RECOVERY IN TERRESTRIAL ECOSYSTEMS ACROSS THE PERMIAN-TRIASSIC BOUNDARY IN SOUTH AFRICA EAR-0230024 PIs: Hallie J. Sims, Marion K. Bamford, and Conrad C. Labandeira The Permian/Triassic (P/Tr) boundary 252 million years ago is recognized as the largest mass extinction in the history of marine life. The terrestrial fossil record indicates that there was widespread and elevated turnover in plants and insects during this interval, but interpretation of the event has been hindered by the apparent lack of a continuous terrestrial sequence spanning the boundary. The Permian and Triassic compression floras in Karoo Basin of South Africa record a temporal series of snapshots of local vegetation, and thus provide a model system to assess extinctions and ecological restructuring in plant communities across the boundary. In addition, the diversity and frequency of insect herbivory in these communities is preserved as damage on fossil leaves, wood, seeds, and other reproductive organs and can be used to assess patterns in plant-insect interactions. PIs project combines examination of specimens in museum collections and new field work to bulk collect plant macrofossils from 23 Karoo localities spanning the P/Tr boundary. Palynological analysis will allow them to integrate the sites with current geochronological information, including new radiometric dates and known vertebrate biozones in the Karoo. The work will allow PIs to test hypotheses related to changes in the composition and relative abundance within plant communities. By integrating quantitative data on plants and their associated insect herbivores, this research will help understand how terrestrial life responded to the most devastating extinction in the Phanerozoic by providing the first rigorous assessment of changes in ecosystems across the P/Tr boundary at multiple trophic levels.