Abstract Detail

Themes of land plant evolution, a celebration of the contributions of Leo J. Hickey

Royer, Dana [1], O'Meara, Brian [2].

Incorporation of phylogenetic signal into leaf-climate models for paleoclimate inference.

In a groundbreaking paper from 1916 in American Journal of Botany, Irving Bailey and Edmund Sinnott developed the intellectual framework for quantitatively reconstructing paleoclimate from the physiognomy (size and shape) of fossil leaves. All leaf-climate approaches that have been developed to date do not incorporate the potential for phylogenetic signal: the tacit assumption has been that phylogenetic history does not significantly impact leaf-climate relationships. However, recent quantitative studies clearly demonstrate that both historic and climatic factors are important for understanding leaf physiognomy: for example, estimating paleoclimate from a site with many members in Betulaceae using a calibration disproportionately represented by Lauraceae may be misleading. Here we develop a strategy for quantitatively incorporating phylogenetic signal into leaf-climate models. For each taxon at a fossil site (species or higher level taxon, such as family), we generate a climate prediction using a multivariate regression based on closely related extant species. Related species are found using a recent molecular phylogeny of over 40,000 species; physiognomic characters come from Peppe et al. (2011, New Phytologist 190:724-739). These individual taxon predictions are then combined to estimate the climate at a site. Our leaf-climate model is the first to explicitly incorporate phylogenetic relatedness. And in contrast to existing approaches that assume that all species at a site contribute equally to the climate inference, our approach exploits the potential for some species to be more climate sensitive than others. For these reasons, our new approach should produce paleoclimate estimates that are more reliable than those from existing approaches.

Broader Impacts:

1 - Wesleyan University, Department of Earth and Environmental Sciences, Middletown, CT, 06459, USA
2 - University of Tennessee, Department of Ecology and Evolutionary Biology, Knoxville, TN, 37996, USA

Keywords:
leaf physiognomy
paleoclimate
Phylogenetic signal.

Presentation Type: Symposium or Colloquium Presentation
Session: C6
Location: Belle-Chasse/Riverside Hilton
Date: Tuesday, July 30th, 2013
Time: 3:45 PM
Number: C6009
Abstract ID:115
Candidate for Awards:None