LB 4-31 - Tree richness structures individual-level leaf metabolomic profiles in a temperate forest experiment in Maryland, USA

Thursday, August 10, 2023

5:00 PM – 6:30 PM PDT

Location: ESA Exhibit Hall

Presenting Author(s)

EG

Eric Griffin, Ph.D.

Assistant Professor of Ecological Forestry
Warren Wilson College
Swannanoa, North Carolina, United States

Coauthor(s)

KB

Karin Burghardt, Ph.D.

Assistant Professor of Entomology
University of Maryland - College Park
College Park, Maryland, United States
CF

Catherine Fahey, Ph.D.

Postdoc Research Fellow
Smithsonian Environmental Research Center
Edgewater, Maryland, United States
MM

Melissa McCormick

Research Scientist
Smithsonian Environmental Research Center, United States
BS

Brian E. Sedio, Ph.D.

Assistant Professor of Integrative Biology
University of Texas - Austin
Austin, Texas, United States
JP

John Parker, Ph.D.

Staff Scientist
Smithsonian Environmental Research Center
Edgewater, Maryland, United States

Although decades of research have typically demonstrated a positive correlation between biodiversity of primary producers and associated trophic levels, the ecological drivers of these associations are still poorly understood. While many suggest that plant metabolomes may be cryptic yet important mediators of such patterns, empirical results are lacking. Here, we used recent innovations in LC-Mass Spec to characterize foliar metabolomic richness and diversity among 15 broadleaved tree species (N = 545 individual trees) in a large-scale temperate tree diversity experiment in Edgewater, Maryland with replicated plots of one-, four-, or 12-species tree mixtures (N = 255 trees per plot, 17,850 trees total). Specifically, we tested whether leaf metabolomic richness and diversity differed among tree species and across tree richness. We found that increasing tree richness had no overall effect on chemical richness or metabolomic diversity (effective species number) across all species within the first four years of growth. However, tree richness caused changes in individual species’ metabolomes. For example, increases in tree richness from one to 12 species decreased Cornus florida foliar metabolomic richness by 6% but increased effective chemical species number by 19%. Moreover, at times tree species richness increases from one to four caused a change in metabolomic richness or diversity, however an increase in tree richness from four to 12 caused the opposite result. For Platanus occidentalis, increasing tree richness from one to four species caused decreases in metabolomic richness and effective species number by 7% and 9%, respectively; however, increasing tree richness from four to twelve species caused increases in metabolomic richness and effective species number by 5% and 23%, respectively. For Liriodendron tulipifera, increasing tree richness from one to four species caused an increase in metabolomic effective species number by 6%; however, increasing tree richness from four to 12 species caused a 28% decrease in metabolomic effective species number. Ultimately, our findings highlight complex but consistently strong impacts of tree diversity on leaf chemistry, suggesting that diversity-induced changes in tree chemistry may mediate additional trophic dynamics (e.g., plant microbiomes, herbivores).