Regional-Scale, Observation-Informed Tropical Forest Diversity in ELM-FATES

Authors

Marcos Longo¹* ([email protected]), Lara Kueppers^1,2, Charles Koven¹, Rosie Fisher³, Gregory Lemieux¹, Ryan Knox¹, Jessica Needham¹, Jennifer Kowalczyk¹, Jeffrey Chambers^1,2, Polly Thornton², Helene Muller-Landau⁴, S. Joseph Wright⁴, Antonio Antonino⁵, Damien Bonal⁶, Paulo Brando⁷, Benoit Burban⁸, Géraldine Derroire⁹, José Silva¹⁰, Eduardo Souza¹⁰, Maria del Rosario Uribe⁷

Institutions

¹Lawrence Berkeley National Laboratory, Berkeley, CA; ²University of California–Berkeley, CA; ³CICERO Centre for International Climate Research, Oslo, Norway; ⁴Smithsonian Tropical Research Institute, Panama City, Panama; ⁵Universidade Federal de Pernambuco–Recife, PE, Brazil; ⁶Université de Lorraine, INRAE, AgroParisTech, UMR Silva, Nancy, France; ⁷Yale School of the Environment, Yale University, Yale, CT; ⁸INRAE, UMR 0745 EcoFoG, Campus Agronomique, Kourou, French Guiana; ⁹CIRAD, UMR 0745 EcoFoG, Campus Agronomique, Kourou, French Guiana; ¹⁰Universidade Federal Rural de Pernambuco–Serra Talhada, PE, Brazil

URLs

https://ngee-tropics.lbl.gov

Abstract

Droughts in tropical ecosystems are increasingly hotter and more frequent, with potentially significant impacts on carbon and water cycles throughout the 21st century. The ability to predict how forests will respond to climate change will largely depend on whether terrestrial biosphere models represent the diversity of individual trees’ trade-offs between allocation of resources to growth and drought tolerance. Here, the project presents its approach to define regional-scale plant functional types (PFTs) for the Functionally Assembled Terrestrial Ecosystem Simulator (FATES). The team pooled trait and allometry data from multiple open-source databases (including TRY and Environmental System Science Data Infrastructure for a Virtual Ecosystem) of 34 traits across 2096 tree species in the Neotropics and used an unsupervised clustering approach to identify and implement PFTs along the main observed trade-off axes. This approach generated five tropical PFTs (four evergreen, one drought-deciduous), with the evergreen clusters representing structural growth strategies (maximum height), tolerance to shade, and leaf stoichiometry. The team tested FATES at multiple mature forest sites along a precipitation gradient (500 to 3000 millimeters per year) in the Neotropics. Researchers found that FATES qualitatively represents biomass differences across dry and moist forests but overestimates drought-deciduous abundance and underestimates evergreen PFT fractions under current climate. The project is currently implementing a multisite parameter sensitivity to further constrain the model predictions. Results hitherto indicate a potential for advancing understanding of PFT co-existence across the tropics using observed traits; however, they suggest that additional data and model process development are needed to quantitatively improve the model predictions.