Patterns of intraspecific and intraindividual trait variation in trees along experimental diversity gradients

Abstract

Phenotypic differences addressed from functional traits are widely used to study forest functioning. However, while ecological studies have traditionally focused on species-level trait differences, recent research emphasizes the need of considering intraspecific and intraindividual trait variation. Using leaf-level data collected in two large-scale forest biodiversity experiments in subtropical China and in Germany, I studied leaf trait variation along diversity gradients. The results show that trees change their leaf strategy and the leaf variability within the crown in response to diversity. Further, intraspecific trait variation is higher in monocultures to alleviate intraspecific competitive interactions and decreases with increasing tree species richness. Last, the results show how the organization of intraspecific and intraindividual trait variation lead to higher functional diversity of forest stands, which highlights their importance for understanding forest functioning.