Variabilidade espacial e estrutura de jovens regenerantes de Jatropha mollissima (Pohl) Baill. em área de caatinga no Semiárido Paraibano.

Abstract

The objective of this work was to analyze the phytosociological parameters and the dynamics of the spatial distribution of young regenerating Jatropha mollissima (Pohl) Baill. in a caatinga area in the semiarid region of Paraíba. The field work was carried out in the Experimental Space Reserved for Studies of Ecology and Dynamics of the Caatinga – Area I of the Laboratory of Ecology and Botany – LAEB/CDSA/UFCG (7°39'38.8'' S and 36°53' 42.4'' W; 538 m altitude) located in the municipality of Sumé. The ecosystem selected for the study has an extension of 1.05 ha, with 96 plots of 10 X 10m arranged in it for analysis of young regenerating J. mollissima. The survey of young regenerating occurred in the months of November and December 2021. The absolute parameters of density and frequency were calculated and the regeneration classes were elaborated. Related to the survey of young regenerating, 1965 individuals were identified. Thus, the absolute density in the sampled area was represented by 2047 individuals.ha-1. Particularly in relation to the absolute frequency and considering the 96 plots sampled, young individuals of J. mollissima were registered in all plots, representing 100% of the total sampled. Evaluating the number of individuals distributed per plot, the one with the highest abundance of young regenerating individuals was 37 (68 individuals). The average height registered was 0.10 m, and the plot that had the highest average height was plot 44 (0.144 m) and the lowest value for plots 33 and 40 with 0.082 m. The average diameter was 0.59 cm, with plot 95 having the highest value (0.947 cm) and plot 18 having the lowest value calculated for the average diameter (0.389 m). Considering the phytosociological parameters of absolute density and absolute frequency by natural regeneration size classes, the highest values were found in Class 1 (0.04 - 0.10 m) with 1439 ind./ha and 98 % respectively. Therefore, the data generated in this work with young regenerating J. mollissima in the Caatinga area offer important subsidies for the definition of strategic actions aimed at the biology of conservation and restoration of degraded ecosystems in the context of the Brazilian semiarid region.