Bamboo dominance in an Atlantic Forest community: a structural, functional and taxonomic approach

Abstract

Native species also have the potential to spread and proliferate disproportionally, causing considerable damage as much as exotic species. The increase in native species dominance is called as overabundance and it has affected communities and ecosystems in many different ways. In Brazil, many woody bamboos are typical examples of invasive native species. Their high dominance usually alters the structure and composition of forests, reducing tree density, total basal area, richness, as well as taxonomic and functional diversity of trees. Merostachys sp. is a common native bamboo genus in the Atlantic Forest and in certain disturbed conditions can become overabundant in forest communities. In order to understand the relationship between bamboo dominance and forest parameters we allocated 30 plots of 10x20 m in a Atlantic forest fragment, we marked and identified all the trees individuals with DAB ≥5cm and we measured the basal area of all bamboo clumps within the plots. We evaluated the relationships between bamboo basal area and structural, taxonomic and functional diversity metrics in a tropical forest community, and how these relationships change among the underlying diameter classes of the community. We found that plots with higher bamboo dominance have lower tree density and higher basal area of dead trees, whereas those plots have higher functional and taxonomic diversity, considering that the niche-filling hypothesis plays an important role in invaded communities at local scale. In addition, we found that bamboo dominance was positively related to high dominance of acquisitive traits species and that those relationships were stronger for small trees than larger trees. Even though we have found strong evidence of the effects of the bamboo overdominance, we cannot affirm that those changes within community were the cause or consequence of invasion. In overall, this study was import to highlight the native bamboo interactions with forest parameters, also bringing new contributions for invasion studies at local scale.