Análise da vegetação de um fragmento de caatinga na microbacia hidrográfica do Açude Jatobá - Paraíba.

Abstract

This study evaluated a fragment of the Caatinga shrubby tree existing in the basin of the dam Jatobá, this work developed at the farm Lagoa Seca, municipality São José do Bonfim, PB. We conducted a floristic and phytosociological, applying the distribution of plots in a systematic manner with a distance of 200 meters between plots in the transect and 300 meters between the transects. We used 34 plots of 20m x 20m (400m2) in each plot were made the following assessments of vegetation for each individual : common name and measuring the circumference at 0.30 m above the ground (C0, 3), measuring the circumference at 1.30 m (CAP) and total height, including those who had CAP> 6 cm. We sampled 3785 individuals belonging to 13 families and 28 species. The most abundant species were Croton sonderianus and Caesalpinia pyramidalis. The families Euphorbiaceae, Fabaceae Fabaceae Caesalpinioideae and Mimosoideae were the most representative in the area. The species with the highest VI was Caesalpinia pyramidalis, this result is mainly due to high dominance and relative density and high frequency. Was found an average volume of 38.77 m3/ha, with a 16.59% accuracy in sampling error. The class time 2.49 m to 5.30 m was obtained more number of trees, 80.14% of all species measured. In the third class of heights species Mimosa tenuiflora, was the one that got a greater number of individuals. The diameter class of 0 - 5 cm, was obtained more number of individuals, but the second class in 5 - 10 cm, is the one with the highest basal area.