Intraspecific Variation In Tree Growth Responses To Neighbourhood Composition And Seasonal Drought In A Tropical Forest

Functional traits are expected to provide insights into the abiotic and biotic drivers of plant demography. However, successfully linking traits to plant demographic performance likely requires the consideration of important contextual and individual-level information that is often ignored in trait-based ecology. Here, we modelled 8 years of growth from 1,138 individual trees in 36 tropical rain forest species. We compared models of tree growth parameterized using individual-level versus species mean trait data. We also compared models that considered regional climatic, local biotic and whole-plant allocation contexts to those that do not. Our analyses show that growth models parameterized using individual-level trait information outperformed those that used species mean trait information and that these models often contradicted one another indicating that the common practice of using species mean trait data requires more scrutiny. Additionally, we found that models including climatic, biotic and allocation contexts outperformed those that did not and provided nuanced insights into the drivers of tree growth in a tropical forest. Synthesis. Here we have shown that the development of models of tree demographic performance upon the basis of traits can be improved through a consideration of individual-level trait variation as well as phenotypic and climatic contexts. We highlight that our ability to understand the drivers of tree population and community structure and dynamics in current and in future climates will be limited if contextual and individual-level data remains understudied.