Leaf traits of Cerrado trees vary according to season of leaf production

Abstract A large number of studies on plant functional traits assume time-invariant species-level mean trait values. Studies examining how leaf functional traits vary according to the season in which leaves were produced are very rare. In this study, we selected four species of trees and evaluated how morphological traits, and mesophyll and stomatal dimensions of leaves produced in the dry season differed from those produced in the wet season in a highly seasonal woodland savanna (cerradão) in the Amazonia-Cerrado transition. We found substantial differences in leaf traits between cohorts of leaves produced in both seasons, with those produced during the wet season characterized by more acquisitive trait values (e.g., high stomatal density, large stomatal pore size and high specific leaf area) than leaves of the same species produced in the dry season which were characterized by water conservative leaf traits. The magnitude of the difference for selected traits was remarkable – e.g., stomatal density of leaves produced in the dry season was on average four times greater than those produced in the wet season. Our results cast strong doubts on the use of mean specific values for syntheses of leaf traits and demonstrate that species in the Amazonia-Cerrado transition exhibit very high intraseasonal variation. Whether this high level of plasticity observed seasonally also applies to response to future climate change remains an open question.