Everything's not lost: Caatinga areas under chronic disturbances still have well-preserved plant communities

Abstract

The caatinga, a thorny deciduous shrub-arboreal vegetation predominant in the semiarid Northeast Brazil region, has faced chronic anthropogenic disturbance since the arrival of Europeans. Areas experiencing strong anthropogenic pressure and climatic vulnerability are often overlooked in floristic and phytosociological studies, leading to limited knowledge about their biological potential. Thus, our objective was to assess the current vegetation state in three severely degraded nuclei undergoing desertification in Ceará and determine, based on the analysis of plant diversity (richness) and structure, if there is potential for natural regeneration. We sampled 36 plots (3.24 ha), measuring trees and shrubs with a diameter at ground level (DGL) ≥ 3 cm. The vegetation was stratified into three degradation levels: open, intermediate, and closed. The open level, most impacted by human activities, exhibited reduced plant richness, density, biomass, and height compared to other levels. In contrast, the intermediate and closed covers, prevalent in the study area, showed no significant differences from each other or from caatinga areas outside the desertification nuclei. We concluded that even severely degraded areas should possess high biological potential due to the presence of preserved remnants serving as reservoirs to maintain diversity and vegetation structure in the region.