Espécies Arbóreas Exóticas: estrutura populacional na Floresta Atlântica do Nordeste

Abstract

The introduction of exotic species, present in different ecosystems in Brazil and around the world, has been a cause for concern among scholars on the subject, due to the risks that these species present to natural communities, ecosystems and their biodiversity. In this sense, the objective of this research was to evaluate the impacts of the introduction of exotic tree species in Atlantic forest ecosystems (Lato sensu) in Northeast Brazil. Thus, using secondary data, searches were carried out for works on the Atlantic forest in the Northeast that presented records of exotic species in their floristic and/or phytosociological lists. For each selected work, data on the inclusion criteria of individuals (trees and regenerants), the study site, name of the species and the number of individuals/relative density of the same, in the different vegetation fragments, were recorded. The survey resulted in 19 studies with the occurrence of exotic species, distributed in the states of Alagoas, Bahia, Pernambuco and Sergipe, totaling 28 exotic species recorded in one or more patches of the Atlantic Forest. The analysis of the inclusion criteria, adopted in the works, shows the presence of exotic species, from the initial phase of the life cycle to the adult phase, showing that some of these species are contributing to the entry of individuals into Atlantic Forest communities and have risks of expansion of their populations. For example, the jackfruit tree (Artocarpus heterophyllus), recorded in 16 of the studies considered and with individuals at different stages of their life cycle. The records of species abundance in quantitative surveys show that nine of the 25 species (Elaeis guineenses, Mangifera indica, Syzygium Cumini, Persea americana, Spondias lutea, Syzygium malaccense, Terminalia cattapa, Annona muricata, Artocarpus heterophyllus) occurred with at least 10 individuals per fragment, with the species Annona muricata occurring with 792 individuals in a single fragment. It is also noted that the species with the highest frequency among the surveys are all included in the lists of invasive species in Brazil. It is clear that fragments of the Atlantic forest in the Northeast suffer from the entry of exotic and/or invasive species, and the list of species may be much larger than those indicated in this study, considering the gap in the availability of information and many studies not including them in the samples.