Phytoosociological Survey of Caatinga Trail under Extensive Grazing in Patos-PB Municipality

The caatinga is a typical Brazilian semi-arid vegetation, where dominant shrub species and some dispersed arboreal individuals are found, in addition to the marked presence of cacti.The aim of the present study was to evaluate the arboreal-shrub component, analyzing the floristic composition and phytosociology in caatinga area under extensive grazing in the Paraíba hinterland. The study area extends over 60 ha, and presents vegetation of the caatinga type with the presence of extensive cattle grazing. The vegetation data were obtained using the simple random sampling method, with plots with a standard size of 20 x 20 m, and randomly arranged 15 sample units. In each sample unit were measured all living or dead individuals, with Chest Height Circumference (CAP) ≥ 6 cm as well as total height of each individual. There were 1285 individuals belonging to 9 families, 16 species, 15 genera. The Fabaceae family obtained the largest number of individuals and species, with the Cenostigma bracteosum species being the most important, with 650 individuals. The first class of diameter, concentrated the largest number of individuals with 627 individuals (48.8%). Regarding height distribution, it was observed that 1154 individuals (89%) are grouped in the first three classes. the study area presents a low diversity, proving that the extensive grazing has been changing the floristic composition of the area.