Can traits predict individual growth performance? A test in a hyperdiverse tropical forest

Area of Science:

• Ecology
• Plant Biology
• Tropical Ecology

Background:

• The functional trait approach posits that plant traits influence individual performance, yet field validation is limited.
• Intraspecific variation in functional traits is crucial for understanding plant strategies and ecological responses.

Purpose of the Study:

• To test the individual-based functional trait approach in a hyperdiverse Amazonian tropical rainforest.
• To evaluate intraspecific trait variation, individual plant strategies, and the functional basis of performance.
• To assess the predictive power of traits on individual stem growth under varying environmental conditions.

Main Methods:

• Studied over 1300 tree saplings across more than 383 species in an Amazonian rainforest.
• Measured 25 traits related to plant growth and defense mechanisms.
• Analyzed the influence of environmental factors, plant size, and measured traits on stem growth rates.

Main Results:

• Observed substantial intraspecific trait variation (44%), suggesting significant acclimation potential.
• Identified two main individual plant strategy spectra: tissue toughness and organ size versus leaf display.
• Found that individual-level traits were poor predictors of stem growth, likely due to trait and growth rate convergence.

Conclusions:

• The individual-based functional trait approach, while reflecting realized traits, offers limited predictive power for individual performance in this ecosystem.
• Species-based and individual-based trait approaches are conceptually distinct, with the former focusing on potential and the latter on realized traits.
• The individual-based approach provides a more realistic perspective on tropical forest community dynamics despite poor individual performance prediction.