Phylogenetic dynamics of Tropical Atlantic Forests

Abstract

Environment and plant interactions are important drivers of forest community assembly and dynamics. This study explored how forest dynamics influence the phylogenetic structure of Tropical Atlantic Forests. We hypothesized that: (a) maximum diameter and maximum height are conserved traits within the phylogenetic lineages; (b) the set of dead large trees are more closely related to the set of living large trees than expected by chance; (c) mortality, recruitment and biomass variation are related to phylogenetic effects. We gathered data from 12,920 trees with diameter (DBH) ≥ 3.2 cm, from nine sites, distributed among seasonal semideciduous submontane forests, evergreen dense forests and gallery forests in Brazil. With this data we computed annual dynamic rates (mortality, recruitment, loss and gain of basal area), phylogenetic turnover and phylogenetic distance between dead and surviving trees, and recruits and surviving trees, within distinct size (DBH) classes. We found an overall tendency for higher mortality than recruitment, and higher gain than loss of basal area. Concomitantly, we detected an increase of phylogenetic clustering caused by exclusion of distant relatives, and a phylogenetic overdispersion among large trees (≥ 30 cm DBH) caused by exclusion of close relatives. We also observed high values of phylogenetic distance among recruits and surviving trees across different size classes. As the maximum height and maximum diameter are conserved functional traits, these findings indicate that negative interactions such as competition-like effects among large trees influence the phylogenetic structure and the forest dynamics, meanwhile successional change continuously excludes unfit phylogenetic lineages while recruits fit phylogenetic lineages.