Cells to ecosystems: fossil xylem is the missing link in reconstructing water use by plants, forests, and global vegetation in deep time

Baylor University, Waco TX

Investigators

Abstract

Plant communities respond to climate change by moving and changing, but current predictions lack mechanistic connections between plant function and environmental change. Plant community responses are observed repeatedly in the fossil record, and could help predict future changes by measuring traits from plant fossils. Much effort has focused on the ways that leaves respond to and record environmental conditions. However, leaves depend on long-lived organs, such as stems, to enable plant function. This study will establish a new database dedicated to plant stem traits from fossil xylem to understand plant community responses to major intervals of ancient climate change. More broadly, this project will prepare a new generation of Earth scientists for this highly interdisciplinary work and expand participation in research through training and mentoring targeted towards underrepresented groups in paleontology through the creation of a paleontology and ecosystem modeling short course. This project is focused on assessing water transport in the xylem of Paleozoic and Mesozoic plants as an adaptation that influenced survivorship across two major intervals of climate change: the Late Paleozoic Ice Age of the Carboniferous-Permian (~300 million years ago [Ma]) and the hothouse climate of the Triassic-Jurassic (~200 Ma). This project will focus on three specific aims: (1) establish a unified xylem fossil functional anatomy database to facilitate (2) prediction of hydraulic traits for extinct taxa and (3) integration of fossil-observed leaf and xylem traits to predict whole-plant function using a modified ecosystem process model (Paleo-BGC). Investigators will use this approach to assess extinct plant water stress and ecosystem function through periods of extreme global climate change and test the hypothesis that coordination of leaf and stem water transport traits distinguished taxa as casualties, survivors, and thrivers during floral collapse and recovery during both global cooling and warming events. This project prioritizes training a new generation of interdisciplinary Earth scientists through training and mentoring opportunities for undergraduate, graduate, and postdoctoral scholars. Additionally, a short course for underrepresented and early career scientists focused on linking paleobotany, plant physiology, and climate change will be created. Pre- and post-course summative evaluations will be applied with an aim to improve future course iterations’ delivery of climate-change-focused interdisciplinary geoscience to the target audience. 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.