HUH Seminar Series - Aaron Lee

Aaron Lee
Postdoctoral Fellow, Organismic and Evolutionary Biology
Harvard University

Title: Using spectroscopy to study plant diversity across time and space in natural history collections

Abstract: The extended specimen concept re-centers specimens as rich sources of biodiversity data and encourages researchers to actively work in natural history collections. Herbarium collections are temporally and spatially resolved, and, globally, herbaria house the entire known plant tree of life. Studies of extended specimens take advantage of these strengths, providing insights into, for example, how traits and biotic interactions have changed over time. We are developing leaf-level reflectance spectroscopy to rapidly and nondestructively obtain phenotypic information from specimens. The physical and chemical manifestation of functional traits and evolutionary history within a leaf can be captured with and retrieved from reflectance spectra. These linkages have been demonstrated with fresh leaves and pressed, dried leaves (herbarium leaf analogues). However, trait retrieval requires destructive sampling to develop trait estimation models. In this talk, I first discuss two approaches to modelling destructively sampled functional traits from specimen-derived spectra. Next, I present two case studies representing how specimen-derived spectra can be used to address ecological and evolutionary research questions. I (1) show that spectrally-derived traits can be used to investigate trait change over 150 years of climate warming, and (2) evaluate the parallel diversification of spectrally-derived traits and spectra on their own in a globally distributed family, Polygonaceae. Finally, I reflect on the challenges and benefits of working with herbarium-derived spectra and share updates from ongoing work with the International Herbarium Spectral Digitization (IHerbSpec) Working Group.