Modeling the Joint Effects of Vegetation Characteristics and Soil Properties on Ecosystem Dynamics in a Panama Tropical Forest. (12th January 2022)

• Record Type: Journal Article
• Authors: Cheng, Yanyan; Leung, L. Ruby; Huang, Maoyi; Koven, Charles; Detto, Matteo; Knox, Ryan; Bisht, Gautam; Bretfeld, Mario; Fisher, Rosie A.
• Is Part Of: Journal of advances in modeling earth systems. Volume 14:Number 1(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-01-12
• Subjects: tropical forest -- coexistence -- vegetation demographic model -- Earth system model -- E3SM‐FATES -- soil properties; Geological modeling -- Periodicals; Climatology -- Periodicals; Geochemical modeling -- Periodicals; 551.5011
• DOI: 10.1029/2021MS002603
• Languages: English
• ISSNs: 1942-2466

Abstract

Abstract: In tropical forests, both vegetation characteristics and soil properties are important not only for controlling energy, water, and gas exchanges directly but also determining the competition among species, successional dynamics, forest structure and composition. However, the joint effects of the two factors have received limited attention in Earth system model development. Here we use a vegetation demographic model, the Functionally Assembled Terrestrial Ecosystem Simulator (FATES) implemented in the Energy Exascale Earth System Model (E3SM) Land Model (ELM), ELM‐FATES, to explore how plant traits and soil properties affect tropical forest growth and composition concurrently. A large ensemble of simulations with perturbed vegetation and soil hydrological parameters is conducted at the Barro Colorado Island, Panama. The simulations are compared against observed carbon, energy, and water fluxes. We find that soil hydrological parameters, particularly the scaling exponent of the soil retention curve ( B sw ), play crucial roles in controlling forest diversity, with higher B sw values (>7) favoring late successional species in competition, and lower B sw values (1 ∼ 7) promoting the coexistence of early and late successional plants. Considering the additional impact of soil properties resolves a systematic bias of FATES in simulating sensible/latent heat partitioning with repercussion on water budget and plant coexistence. A greater fraction of deeper tree roots can help maintain the dry‐season soil moisture and plant gas exchange. As soil properties are as important as vegetation parameters in predicting tropical forest dynamics, more efforts are needed to improve parameterizations of soil functions and belowground processes and their interactions with aboveground vegetation dynamics. Plain Language Summary: Through their impacts on the energy, water, and gas exchanges, vegetation characteristics and soil properties may influence ecosystem dynamics in tropical forests. This study examines how these two factors affect tropical forest dynamics simultaneously, including forest growth and composition. We use a state‐of‐the‐art ecosystem demography model and evaluate the modeling results with field data collected at a primary tropical forest site, the Barro Colorado Island, Panama. The results show that soil hydrological parameters are as important as plant traits for regulating tropical forest successional dynamics and composition. The response of forest diversity to vegetation characteristics and soil properties has important implications for how climate and land use/land cover changes influence tropical forests and their role in carbon‐water‐climate feedback. Key Points: An ecosystem demography model is used to examine how vegetation and hydrologic parameters jointly affect tropical forest dynamics Soil hydrologic properties, particularly a parameter related to the soil retention curve, play a key role in controlling forest diversity Belowground components such as the fraction of deeper tree roots are important for regulating dry‐season forest dynamics