Population structure of Melocactus ernestii Vaupel subsp. ernestii (Cactaceae)

Abstract

The cacti are an important component of the flora of Caatinga and have suffered from the predatory exploitation of their populations and the degradation of their occupation sites. This study aimed to characterize a population of Melocactus ernestii Vaupel subsp. ernestii occurring on a rocky outcrop in the city of Pocinhos, PB, aiming to support information for the proper management and conservation of the species. All along the rocky outcrop were allocated 60 plots of 1 m². The sampled individuals were classified according to their ontogenetic stage, evaluating the density, height, diameter at middle section, and the death toll. To evaluate the spatial distribution of the species the Morisita Index of Dispersion (Id) was calculated and to check the influence of an ontogenetic stage on the other, we applied the linear correlation coefficient (r). We sampled 789 individuals, of which 595 were adults and 194 youths. The value of Id was 1.46 indicating which the population distribution pattern showed aggregate. The value of r = -0.4887 shows a negative linear correlation between ontogenetic stages. The population does not show stability, with a small number of stock individuals.