NSF PRFB FY 2023: Testing the Latitudinal Diversity Gradient

David, Kyle T, Nashville TN

Investigators

Abstract

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2023, Integrative Research Investigating the Rules of Life Governing Interactions Between Genomes, Environment, and Phenotypes. The fellowship supports research and training of the fellow that will contribute to the area of Rules of Life in innovative ways. This fellowship aims to study patterns of distribution of living organisms across tropical and polar latitudes. Prior studies of the distributions of species show that the diversity of living organisms tends to decrease with distance from the equator. Even though this pattern is global and has been known since the days of Charles Darwin, we still do not know what causes this trend. This research will explore how the distinct diversity of living organisms across latitudes arose by comparing species formation in tropical, temperate, and polar environments. By discovering regions where species are more likely to originate, the fellow will work to uncover the history and distribution of biodiversity across the planet. A more complete understanding of how biodiversity operates across geographic scales will contribute to our ability to mitigate invasive species, diseases and their vectors, and the costs of climate change. Research activities will be accompanied by several education and outreach efforts directed at incarcerated and formerly-incarcerated populations in the Nashville area. This project will explore the latitudinal diversity gradient by conducting a series of large-scale diversification studies. Due to the breadth of sampling required to estimate global diversification, current studies are largely limited to densely sampled groups in vertebrates and vascular plants. This limits the scope of our understanding both phylogenetically and geographically, as these groups are largely restricted to tropical and temperate climes. To address these knowledge gaps, this research will generate global diversification gradients in a previously unexplored kingdom (Fungi) and two marine invertebrate clades (Polynoidae and Pycnogonida) with circumpolar distributions. Diversification gradients will be inferred through a combination of methods explicitly designed to accommodate concerns recently raised over the ability of diversification analyses to distinguish between hypotheses. These include nonparametric approaches, hidden state speciation extinction models, and new methods incorporating diversity-dependence and paleogeographic shifts. The work will also be integrated into multiple broader impact efforts, including the Evolutionary Studies Initiative and Maximizing Access to Research Careers programs at Vanderbilt University, as well as develop new outreach and engagement materials geared toward prison education. 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.