The role of leaf traits in forest ecosystems : mediators in the relationship between biodiversity and ecosystem functions

Abstract

This thesis investigates how leaf traits and within-individual leaf trait variation respond to biodiversity and local light availability, as well as how these factors affect tree growth. Using three biodiversity experiments in the tropical, subtropical, and temperate forest, it shows that leaf trait variation decreases with increasing species richness and is shaped by light gradients within tree crowns. However, biodiversity and neighboring trees influence leaf traits beyond light effects. Furthermore, leaf trait variation mediates the relationship between biodiversity and tree growth. Trees in monocultures exhibit higher within-individual trait variation, partly compensating for reduced interspecific diversity. Overall, these findings highlight, that adjustments in leaf traits link biodiversity and ecosystem functioning across biomes and species, emphasizing the need to consider within-individual variation in forest ecology.