Has the sixth mass extinction event in Earth’s history already begun? If so, what lessons does the fossil record offer for how ecosystems will respond to massive loss of biodiversity? In this talk, I will compare the intensity and ecological selectivity of past mass extinction events to the current biodiversity crisis using a new database of animal sizes and ecological traits spanning both fossil and living species. Both on land and in the ocean, the strongly selective removal of large-bodied animals across many taxonomic groups is unique to the current diversity crisis and appears to be a unique signature of human influence on the biosphere. The geological record provides many past examples of climate warming, ocean acidification, and sea level change that can help to inform projections of future environmental conditions. However, it does not contain a biodiversity crisis with a similar pattern of extinction, adding to the challenge of forecasting future ecosystem function.
Professor Jonathan L. Payne