Juliano Ricardo Fabricante

Biological invasion of Artocarpus heterophyllus Lam. (Moraceae) in an Atlantic Forest fragment in Northeastern Brazil: impacts on phytodiversity and soils of invaded sites

The objective of this study was to evaluate the impacts caused by A. heterophyllus on the richness and diversity of vegetation, and the soils, in a fragment of open rainforest, in Areia, PB. The study area is located in the Campus II of Universidade Federal da Paraiba. In this fragment, 10 pairs of plots of 100 m² were established. Half of these sampling units (AI - environment invaded) were laid out so there was an adult A. heterophyllus in the center. Alongside each of these plots, one sample unit (AN - natural environment) was allocated. We evaluated the number of species, the abundance of individuals, diversity and evenness, and the chemistry of the soils. We sampled 14,008 individuals belonging to 79 species, of which there were 12,369 individuals and 50 species in the AI and 1,639 individuals and 75 species in the AN. The diversity and evenness of AI were 0.24 and 0.06, respectively, and for AN they were 3.42 and 0.79. All variables were significantly different showing that A. heterophyllus modify the environments where it grows. The concentrations of some elements in the soil changed while others did not. It was found that A. heterophylus forcefully alters species richness, diversity of vegetation and soils of invaded sites, which suggests that actions to control this species are necessary.

Non-native and invasive alien plants on fluvial islands in the São Francisco River, northeastern Brazil

This paper is the result of a survey of the alien flora present on fluvial islands in the Sao Francisco River, northeastern Brazil. The floristic similarities between the islands wereassessed, as well as the relationship between area size and species richness. The study covered eight islands in the Sao Francisco River Valley and was carried out in a period of eight months. Thirty one alien species were registered, six of them ( Amaranthus viridis , Calotropis procera , Cenchrus ciliaris , Enneapogon cenchroides , Prosopis pallida and Ricinus communis ) present on all islands. The highest number of invasive alien species (26) was recorded on Massangano Island. The floristic similarity between the islands varied between medium and very high, while the number of alien species present was positively correlated with area size. The study demonstrates that the biodiversity on these eight fluvial islands is endangered, especially due to the presence of alien species capable of invading natural areas.