Early successional understory communities show idiosyncratic phylogenetic patterns in Neotropical silvicultural plantations

One approach in forest restoration is to plant trees that will establish an initial canopy to promote forest recovery through the colonization of other species. The identity of the planted tree affects which species are able to recruit in its understory. Here we evaluate the phylogenetic structure of young understory plant communities recruiting beneath eleven different species planted in single species stands and relate those structures with processes affecting community assembly. We expected the presence of negative biotic interactions between closely related overstory and understory species, as well as among related understory species, to lead to phylogenetic overdispersion. However, we did not find consistent phylogenetic patterns maybe due to the young age of the understory communities at the time of sampling. Most overstories showed a higher than expected presence of close relatives due to the recruitment of conspecifics, whereas, the higher recruitment of the ancient clade of Piperaceae beneath Fabaceae trees led to overdispersion. The presence of various Asteraceae species in understories that had been invaded by the grass, Saccharum spontaneum, led to significant clustering suggesting the conservatism of traits that allow overcoming the strong competition imposed by the grass. Phylogenetic patterns among the recruiting species showed that dispersal and competition are playing a role in shaping the communities. Our results highlight the importance of choosing an adequate set of species to plant in a restoration project since they dictate the subsequent regeneration of a forest community.