A new ecological-severity ranking of major Phanerozoic biodiversity crises

A new ecological-severity ranking of the major Phanerozoic biodiversity crises is proposed in which the Capitanian crisis is ranked lesser than the Frasnian (Late Devonian) but greater than the Serpukhovian (end-Mississippian), and the Famennian (end-Devonian) crisis is ranked as equal in ecological impact to the Hirnantian (end-Ordovician). Two new decouplings between taxonomic severity and ecological severity are revealed in these analyses, the Capitanian and Famennian crises, in which the ecological impact of the biodiversity loss was markedly different from the magnitude of the biodiversity loss. These analyses also reveal that the “Great Devonian Interchange” (GDI) invasive-species event in the Givetian biodiversity crisis may provide an important palaeoecological analog for the study of present-day extinction and homogenization in ecosystems produced by modern invasive species.