Nos caminhos dos relevos residuais contribuição a ecohidrologia de encostas no semiárido brasileiro

Abstract

The conditions of a semi-arid climate impose on the vegetation mechanisms of survival to the absence of water, which occurs in part in the caatinga biome. Although it presents a composition xeric, the caatinga also presents species of vegetation of humid environments in crystalline slopes and in ciliary forests. Regarding the crystalline slopes, they are distributed in the botanical understanding that comprises the top and not its surroundings, leaving a gap in the understanding of the hydrological potential that these outcrops provide. In view of this, this thesis consists in analyzing its hydrological and ecological potentials of the crystalline slopes as fundamental in the maintenance of more developed soils and diverse vegetation in these environments. The areas studied were the Salambaia Site located in the municipality of Cabaceiras-PB, and Serra da Engabelada in the municipality of Congo-PB, both of which are located in Cariri Paraibano. The methodology used consisted in the analysis of the physical environmental system of crystalline slopes, its characterization through remote sensing analysis, morphological description, phytosociological survey and generation of landscape units indicating the geomorphological typologies. With the characterization of the established study areas, a macroclimatic analysis was presented, expressing the behavior of the local semiaridity, where its parameters served as inputs to obtain the hydrological contribution. The consequences can be observed in the pedological and phytosociological results through ecohydrology. It was possible to observe that the crystalline slopes present more than 75% of hydrological contribution to their environment. This fact conditioned the generation of more developed soils with high potential of organic matter in the surface, which is reflected in the vegetal species more demanding in water found in these areas. Thus, the presented results express the dynamics of the local vegetation and the hydrological potential of the slopes. As for the thirteen soil profiles collected in the two study areas, it is observed that in the Salambaia site the soils close to the rock outcrops had 65% organic matter on the surface, while in the Engabelada 50% range, which conditioned the nine species of plants with higher water requirement, totaling these 296 occurrences of individuals in the Salambaia site, while Serra da Engabelada presented 98 individuals. The allocation of water in its surroundings helps to maintain these environments, where a refuge is evidenced maintained by the rocky outcrop, consisting of a zone of exception of caatinga.