Diversidade florística entre fragmentos de Caatinga, Piauí, Brasil

Abstract

The Caatinga biome is characterized by xerophyte vegetation and has a rich floristic diversity, but is fragmented by anthropic action. This study aimed to evaluate the floristic and structural differences between Caatinga fragments with different levels of conservation in the state of Piauí. Twenty-six plots of 20 m were × 20 m, divided into two areas (AI and AII). All living individuals with diameter at breast height were measured ≥ 5 cm. In The IA, 1532 living individuals were measured distributed in 14 botanical families and 38 species. The families with the highest number of species were Fabaceae (18), Apocynaceae (2) Myrtaceae (2) and Combretaceae (2). In area II, 787 individuals, 10 families and 30 species were sampled. The families Fabaceae (16), Combretaceae (2) and Euphorbiaceae (2) were the most representative in number of species. The Shannon diversity and pielou equability indices were 2.71 nats/ind and 0.76 AI and 2.60 nats.ind-1 0.75 AII, respectively. The species Combretum glaucocarpum, Cenostigma macrophyllum, Pterocarpus villosus, Hymenaea eriogyne and Ephedranthus pisocarpus together contributed 56.28% of the importance value in AI. Combretum glaucocarpum, Pityrocarpa moniliformis, Cenostigma macrophyllum, Combretum leprosum and Machaerium sp, together contributed 56.40% of the importance value in AII. In both areas there were differences in phytosociological parameters, which explains distinct regeneration processes.