Evolution and climate change: elucidating the controls on species’ responses to 4 Myr of environmental change in the Atlantic Coastal Plain, USA

Erin Saupe
Derek Briggs
Start Date: 
August, 2014

We are altering all facets of our planet at an unprecedented rate, from the biosphere, to the hydrosphere, to the atmosphere. Of primary concern is how these changes will affect the biodiversity we rely on for our continued existence, including food and medicine. Many scientists are asking whether we face a sixth mass extinction event of similar magnitude to the others known from the past 540 million years; a question critical to understanding the causal factors behind such an event and developing proper conservation measures. Determining whether we will, or have already crossed the threshold from normal background to mass extinction is challenging, because the other five mass extinctions are recorded primarily in the near-shore marine fossil record of shelly invertebrates, and we know little of the diversity dynamics within these groups today. Consequently, I will perform a detailed comparison of the Plio-Pleistocene and modern molluscan faunas of the Atlantic Coastal Plain to determine the evolutionary potential of these taxa to cope with environmental changes occurring today. My three study objectives (below) will determine whether concerns over a 6th mass extinction are overblown, or whether we are already exceeding thresholds not crossed in millions of years. The effects of a warming world on molluscan communities in near-shore environments have critical implications for biodiversity in general and for commercial fisheries, particularly since two of the target species are of economic importance (i.e., Crassostrea virginica and Dinocardium robustum).

To examine long-term evolutionary responses of marine mollusks to environmental changes, I will focus on three objectives that use Ecological Niche Modeling (ENM) and Geographic Information Software (GIS). These methods have been applied only recently to paleontological data. ENM is a quantitative technique used to estimate the environmental tolerances of species by statistical correlation of occurrence data with spatially-explicit environmental characteristics, a method in which I have extensive research experience. Niches of species will be calculated using the modeling algorithm Maxent, inputting previously-obtained (paleo) environmental data for the Pliocene through Recent from NASA GISS and the Hadley Climate Centre, UK.