Characterization and attributes of herbaceous vegetation in a Caatinga fragment in the State of Sergipe, Brazil

ABSTRACT Variations in environmental factors are expected to be responsible for the diversification of herbaceous plants in the Caatinga (dry forest). We analyzed the composition, floristic similarity and structure of the herbaceous vegetation in a Caatinga fragment in the municipality of Poço Verde, Sergipe State, Brazil. In addition, the influence of precipitation on richness among different Caatinga areas was evaluated. We installed 30 subplots and the floristic composition was complemented by collections made around these subplots. A total of 80 species were found, of which 43% are typically from disturbed areas of Caatinga. Among the Caatinga areas, precipitation did not explain the variation of richness; similarity values were determined by environmental heterogeneity. The parameters of Shannon-Wiener diversity and Pielou's evenness were within the range expected for Caatinga disturbed areas. Based on evidence supported by previous studies, we believe that human disturbance influences the composition and the structure of the studied herbaceous vegetation. Therefore, conservation actions are recommended.