The problem of biodiversity representation in forest dynamic models models has long been an impediment to a detailed understanding of ecosystem processes. This challenge is amplified in species-rich and high-carbon tropical forests. Here we describe an individual-based and spatially explicit forest growth simulator, TROLL, that integrates recent advances in plant physiology. Processes (carbon assimilation, allocation, reproduction, and mortality) are linked to species-specific functional traits, and the model was parameterized for an Amazonian tropical rainforest. We simulated a forest regeneration experiment from bare soil, and we validated it against observations at our sites. We also assessed the model’s sensitivity to a number of key model parameters. Finally, we tested whether variation in species richness and composition influenced ecosystem properties.
Results/Conclusions
Simulated forest regeneration compared well with observations for stem densities, gross primary productivity, aboveground biomass, and floristic composition. After 500 years of regrowth, the simulated forest displayed structural characteristics similar to observations (e.g., leaf area index and trunk diameter distribution). Species richness had a positive effect on ecosystem processes, but this effect was controlled by the identity of species rather by richness per se. This model should be applicable to many tropical forests sites, and data requirement is tailored to ongoing trait collection efforts.