Biological invasion by Cenchrus ciliaris L.: is there an impact on Caatinga composition and diversity of herbaceous stratum?

Abstract

Cenchrus ciliaris is native to South Asia and West Africa, considered one of the main invasive exotic species of Caatinga. This study aims to evaluate the effects caused by C. ciliaris on the composition, structure and diversity of Caatinga herbaceous stratum. The study area was divided into five environments, in each were allocated 10 plots measuring 1m x 1m, in which five with sites invaded for C. ciliaris and five in places non-invaded. At each sampling unit the number of individuals, the coverage and biomass of each species were known. The evaluated elements were density, frequency, dominance, besides to the diversity and environment similarity. For the sampling were selected 12 families, 16 genus, 19 species and 778 individuals. In general, this invasive exotic showed high coverage and density values, even with the presence of other native species, thus demonstrating the aggressiveness of C. ciliaris. All environments showed significant differences in terms of diversity, when compared to the conditions of invaded and non-invaded. The dissimilarity analysis demonstrated the consistent group’s formation between invaded and non-invaded conditions. This study showed the C. ciliaris ability to change environments, affecting the richness and biodiversity.