Análise da composição florística e estrutura de jovens regenerantes em área ciliar de caatinga no Cariri Ocidental Paraibano.

Abstract

The objective was to analyze the floristic composition and phytosociological structure of young regenerants in a degraded riverside area of Caatinga in the municipality of Livramento, Semiarid Paraíba. The work comprised two inventories, one in the dry season (September/2023) and the other in the rainy season (February/2024). In the riparian forest studied, 50 contiguous plots of 10 x 10 m were arranged and in the center of each one a subplot of 1 x 1 m was plotted to evaluate the regenerating stratum. The parameters of density, frequency, dominance and importance value were calculated. The Shannon diversity index (H’) and the Pielou evenness index were also determined. In the two inventories carried out in the Verde stream, 12 species were recorded, distributed in 12 genera and six families. The most abundant families in terms of number of species were Euphorbiaceae and Fabaceae. The predominant component was trees with nine species and shrubs were represented with three species. In this study, a density of 106 individuals was collected, of which 60 were inventoried in the dry season and 46 individuals in the rainy season. Considering the inventory in the dry period, the species with the highest Importance Value (VI) were Mimosa tenuiflora (Willd.) Poir., Cenostigma pyramidale (Tul.) Gagnon & G.P.Lewis and Croton blanchetianus Baill. Related to this parameter for the rainy season, the most prominent species were Anadenanthera colubrina (Vell.) Brenan, Manihot carthagenensis (Jacq.) Müll.Arg. and C. pyramidale. The diversity and evenness values were 1.99 nats.ind.-1 and 0.83 (dry period) and 0.56 nats.ind.-1 and 0.35 (rainy period) respectively. Related to the hypsometric and diametric distribution, it was recorded in both inventories that the largest number of individuals were concentrated in the classes with the lowest values. Therefore, the information generated is important support for proposing strategic actions aimed at managing riparian areas in the context of the Caatinga Biome, thus being in compliance with objectives 6 and 15 of the sustainable development goals of the 2030 agenda.