Variação intraespecífica de atributos funcionais em espécies arbóreas da Floresta Atlântica

Abstract

Understanding how planting diversity modulates plant functional trait expression is central to improving tropical forest restoration. We assessed how species richness (1, 3, and 6 species) influences the expression, variability, and coordination of functional traits in two pioneer trees, Croton urucurana and Pleroma granulosum, in 4- year-old Atlantic Forest restoration plantings. We measured leaf morphological and physiological traits and plant height in 454 individuals. Analyses combined nonparametric tests of intraspecific variation with generalized linear mixed models and trait–trait models. Species identity was the main driver of trait expression, whereas species richness produced trait–specific shifts in mean values: SLA, LA, and fresh weight increased with richness, while LDMC and Fv/Fm declined, and dry mass exhibited a non-linear response to richness. Intraspecific trait variability did not change consistently across richness levels, and core patterns of trait coordination were conserved, including the negative SLA–LDMC trade-off and positive scaling relationships between leaf area, dry mass, and height. Photochemical efficiency was negatively associated with acquisitive traits, indicating short-term physiological costs associated with acquisitive trait expression. Overall, species richness modulated mean trait expression without increasing within-species variance or reorganizing trait architecture, highlighting identity-dominated assembly during early restoration and informing trait-based species mixtures that combine rapid canopy development with physiological stability.