Population structure and effects by the invasive exotic Indian-Almond over autochthonous vegetation from a sandbank

Abstract

In the face of the severe effects caused by biological invasions, this study aimed at evaluating the population structure and impacts caused by the invasive exotic species T. catappa L. over native plant composition, richness and diversity. The study area is located at Atalaia Beach, Aracaju, Sergipe, Northeastern Brazil, and comprises sandbank sites. In order to evaluate the population structure of this invasive exotic species and its impacts on the biota, pertinent statistics were carried out. The results demonstrated that T. catappa shows density of 9,480 ind.ha -1 , being 8,430 ind.ha -1 for non-adults and 1,050 ind.ha -1 for adults, and self-regenerating population. The average species richness for invaded (I) areas and non-invaded (NI) were 6.1 ± 2.42 and 9.7 ± 2.45, respectively. The average abundance of individuals in NI was 1,057.6 ± 432.85 and 184.9 ± 126.66 for I. The diversity and the equability were 2.38 and 0.66 in I and 2.86 and 0.75 in NI, respectively. Thus, T. catappa causes significant impacts on species composition and richness, abundance and autochthonous diversity.