Influence of functional traits on the demographic rates of 47 arboreal species in a tropical forest in northeastern Brazil

Abstract

Influence of functional traits on the demographic rates of 47 arboreal species in a tropical forest in northeastern Brazil. Based on the premise that species use different strategies for acquiring and maintaining resources, it is possible to identify their similarities as determined by particular trade-offs between traits, the present work examined the specific leaf area (SLA), basic wood density (BWD), maximum height (Hmax) and seed shape (SS) of 47 arboreal species in a moist semi-evergreen tropical forest in northeastern Brazil and investigated the influence of those traits on plant mortality rates (MR) and growth (BAG). BWD and Hmax were the best predictors of mortality rates. The factorial analysis explained 70.4% of the total variability, distributed among three factors composed of traits and rates. MR and Hmax were found to be more readily observed when orthogonally rotated by the varimax method, with the first factor explaining 26.9% of the variance. Cluster analyses and principal component analyses, whose matrices contained the variables MR, BAG, SLA, and Hmax for each species, confirmed the discriminant analysis and allowed the identification of four functional groups. The fact that some of the correlations encountered differed from previously published results (such as the negative relationship between maximum height and mortality) may reflect regional climatic seasonality or indicate that this strategy benefits plant species that reach the upper canopy and thus become well-established.