Collaborative Research: Harnessing a high-resolution fossil record and novel (AI) workflows to study the effects of climate change on mammalian functional diversity

Functional diversity refers to the range of biological functions and ecological roles that organisms within a community perform. While functional diversity has been measured in various modern communities, it remains unknown how it changes over long timescales or how it responds to sudden shifts in climate. The Paleocene-Eocene Thermal Maximum (PETM) was a period of rapid, intense global warming ~56 million years ago that is well preserved in the Bighorn Basin, WY. This PETM record documents changes in temperature and aridity, fossil leaves and pollen, and a sample of 20,000+ fossil vertebrates in a precise temporal framework. This project analyzes changes in the functional diversity of mammal communities from before, during, and after the PETM. Elucidating the relationship between mammal functional diversity, floral composition, and abiotic factors such as temperature is key to understanding the biotic response to changes in climate. To achieve these goals, this project develops new, publicly-available AI tools with broad flexibility for paleontologists, recruits undergraduate students for training in STEM research, and implements a fieldwork education program designed to train the next generation of paleontologists. To characterize mammalian functional diversity, this project generates rich 3D datasets from micro-CT scans of mammalian molars, tarsal elements, and distal phalanges. A new set of AI tools will be trained on diverse pilot datasets to rapidly isolate, segment, and crop 3D surfaces of these elements for functional measurements. Measurements include molar dental topography, tarsal facet curvature, and linear measurements of distal phalanges from a stratigraphically-resolved fossil sample spanning the PETM. Measurement of functional diversity permits characterization of the mammalian fauna without resolving many challenging and complex questions about taxonomic affiliations while directly testing whether abiotic drivers such as temperature or biotic drivers such as plant community composition have a greater influence on mammalian functional diversity. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.