Effects of a native bamboo species on tree regeneration diversity of a subtropical Atlantic forest

Abstract

The presence of native bamboo species is considered a factor that affects the dynamics of plant communities in tropical and subtropical forests. In southern Brazil, Merostachys skvortzovii is a long-lasting species (reproductive cycles of 32 years) highly dominant in disturbed areas, causing structural changes in the tree community. In this work, we assessed changes in regeneration communities in 11 years after a reproductive event of M. skvortzvii. We asked if canopy openness and time after bamboo reproduction affect taxonomic and functional diversities of regeneration communities. We installed 20 permanent plots were randomly distributed in the continuous canopy (CC) and open canopy (OC), measured bamboo culms density, and surveyed the regeneration community over the period 2008–2017, and used a generalized linear model to explore the effects of the environment and presence of bamboos on the diversity of regeneration community. We observed an increase in abundance, species richness, and beta diversity over time after the reproductive event, but the time did not affect the Shannon-Wiener index. The canopy opening positively affected the individual abundance species richness, beta diversity, Functional richness (FRic), Functional evenness (FEve) and Functional dispersion (FDis). Also, we found an effect of the canopy opening on the functional attributes positively affecting specific leaf area (SLA) and negatively affecting leaf mass area (LMA) and Leaf carbon content (LCC). We concluded that, despite the intense colonization after the reproduction, the bamboo population follows a decreasing dynamic without negative effects on the regeneration of subtropical forest species, which are more affected by the dynamics of the gaps than bamboo presence. These results show that the subtropical Atlantic Forest regeneration community can restructure itself in the understory without the need for bamboo management.