Comparative study of phytosociological structure of two fragments of Caatinga in different levels of conservation

Abstract

The objective of this work was the comparison of vegetation structure of two Caatinga fragments with primary and secondary levels of ecological succession, located at Embrapa Semiarido, Petrolina, State of Pernambuco, Brazil. For floristic survey it was used the method of plots, where 10 sampling units of 8 m x 40 m randomly distributed were plotted. All living individuals with diameter at ground level (DGL) ≥ 3 cm were inventoried and also measured their total heights. We observed significant differences in the diametric structure, but the distribution of hypsometric frequency showed that the majority of individuals in both areas were small-sized (< 5 m). Through similarity analysis and principal coordinates, we observed the formation of three distinct groups when compared to other surveys in Caatinga sensu stricto. The results showed that the studied areas have floristic richness compatible with Caatinga environments, the fragments are in early stages (Area I) and intermediate succession (Area II) and 30 years of regeneration were not enough for area I to achieve a level of development similar to the ecologically better conserved area.