2024 Abstracts

Unraveling the Mechanisms of Below- and Aboveground Liana-Tree Competition in Tropical Forests


David Medvigy1* (dmedvigy@nd.edu), Zhuoran Yu1, Jennifer Powers2, Peter Tiffin2, Jérôme Chave3, Isabelle Maréchaux4, Alejandra Perez-Enriquez2, Ariadna Mondragon2, Laura Jessup2


1University of Notre Dame, Notre Dame, IN; 2University of Minnesota–Twin Cities, Minneapolis/St. Paul, MN; 3Le Centre National de la Recherche Scientifique, Toulouse, France; 4Institut National de la Recherche Agronomique, Montpellier, France


Trees and lianas dominate the canopy of tropical forests and comprise the majority of tropical aboveground carbon (C) storage. These growth forms respond differently to variation in climate and resource availability. The overarching objectives of this project are (1) to carry out an observational campaign to advance the understanding of liana traits and strategies; (2) develop a liana-enabled forest dynamics model that leverages the observations; and (3) to engage with the Earth System Modeling (ESM) community to plan for the eventual inclusion of lianas into ESMs. Here, researchers report on four activities which have brought the team closer to meeting these objectives:

  1. The team measured and analyzed liana traits. Researchers found marked differences between lianas and trees in terms of their hydraulic traits and xylem anatomical traits. The team also identified significant variation in hydraulic traits across liana species.
  2. Researchers incorporated these results into a reduced model, and subjected the model to different tropical hydroclimate scenarios. Due to differences in hydraulic conductivity, the model indicated that lianas are much more susceptible than trees to reaching a hydraulic threshold for viability by 2100.
  3. The team measured tree growth and liana colonization status of over 1,700 trees at a study site in Guanacaste, Costa Rica. It was found that the number of colonized trees is increasing and that heavily infested trees have lower relative growth rates that other trees. Liana colonization also impacted the relationship between tree growth and rainfall.
  4. Researchers incorporated lianas into the TROLL forest dynamics TROLL represents the three-dimensional canopies of trees and lianas. Researchers have carried out a sensitivity analysis and tested the model’s ability to simulate observed patterns.
  5. The team simulated liana-enabled forest dynamics in TROLL. These dynamics included the ability of lianas to colonize multiple trees and the ability of trees to shed lianas.