To find out the critical factors that allow species to survive during times of extreme stress, Dr. Song has compiled a fossil database at high temporal resolution for the interval from the latest Permian to the start of the Jurassic. This database consists of over 50,000 fossil occurrences derived from ~1500 literature sources. Based on the database, we evaluate the magnitude of the background extinction rates in the Early Triassic and shown that the late Smithian extinction was the third biggest crisis in the past 250 million years (Myr) based on the generic extinction rates metric. Analysis of the fossil database has discovered the surprising result that the ecological structure in Triassic oceans changed at a pace that was an order magnitude slower than the recovery of diversity. This important result has shown the top-down rebuilding of marine ecosystems was still underway in the latest Triassic, ~50 Myr after the mass extinction, and contrasts with the ~5 Myr recovery required for biodiversity recovery. It also shows that trends implicated in the end-Triassic mass extinction (~50 myrs after the end-Permian extinction) were actually part of the long-term changes still underway after the earlier extinction. Previously late Triassic diversity/ecology trends have been explained as a precursor to the end Triassic mass extinction when in fact, in context, they are seen to be a legacy of the preceding mass extinction at the end of the Permian.
Two manuscripts have been written about these important discoveries:-
(1) Song H.J. and P.B. Wignall, The late Smithian extinction was the third biggest crisis of the past 250 million years, submitted to Geology.
(2) Song H., P.B. Wignall, and A. Dunhill, Prolonged top-down recovery of marine ecosystems in Triassic oceans. In preparation for submission to SCIENCE.
