Cobertura e regeneração vegetal como preditores do processo de desertificação na caatinga

Abstract

The Caatinga is one of the most diverse dry forests on the planet. Half of its original coverage is degraded, and it is currently identified as one of the main areas in the process of desertification. The process of natural regeneration depends on climatic, edaphic conditions and the adult stratum present in an area. Despite its importance, this process is little known in the Caatinga. We aim to analyze the regeneration stratum and indicators of desertification under different levels of vegetation cover in the Brazilian semiarid region. Our study was executed in the driest region of Brazil. We classify our studied areas into Area I (less vegetation cover) and Area II (greater coverage). Six plots of 50 x 20 m were delimited for sampling the adult stratum, the regenerative stratum and soil in each area. Our results show interactions between soil characteristics and adult and regenerative stratum. The Area II showed greater diversity and a greater number of exclusive species; in contrast, in Area I, the dominance of species more resistant to limiting conditions was observed, such as Aspidosperma pyrifolium Mart. & Zucc. The contents of C and N in the soil indicated a positive and significant correlation with the diversity of the regenerative stratum. The data revealed that the area with less vegetation cover, richness and diversity presented indications of the desertification process.