INFLUENCES ON THE ECOLOGICAL SEVERITY OF MASS EXTINCTIONS

Research has shown that the ecological and taxonomic severity of extinction events is often decoupled. For example, the end-Ordovician extinction event was taxonomically severe, but had minimal impact ecologically. The end-Devonian event, on the other hand, had severe ecological consequences, but had comparatively little loss in taxonomic diversity. This study aims to address why this decoupling occurs, and what influences the ecological severity of mass extinctions, by analyzing the distribution of guilds across major extinction events. Guilds are made up of diet, motility and tiering categories, as defined by Bambach (2007). Through Bambach’s classification, there are 216 possible combinations of life modes, and 107 are represented in the dataset of marine invertebrates used here. This study focuses specifically on the guilds made up of marine invertebrate genera living in reefs. This approach will answer the question of whether extinctions concentrated in few guilds have more severe ecological consequences than extinctions that are spread out over many guilds, and vice versa. Previous research has shown that the ecological severity of extinctions is tied to the removal of ecologically significant taxa from the system, suggesting that high extinction rates in certain guilds will have more severe ecological consequences.