Carbono e recaatingamento: efetividade da recuperação de áreas degradadas por mineração e protocolo de regeneração conduzida

Abstract

The research investigated the effectiveness of the recovery of mining-degraded areas in the Caatinga biome, with emphasis on natural regeneration through fallowing and on the use of soil carbon as an indicator of environmental quality. The study was based on two central hypotheses: (1) the analytical parameters and monitoring routines adopted in the PRADs – acronym for Degraded Area Recovery Plan – exhibit methodological weaknesses capable of compromising the assessment of restoration outcomes; and (2) soil carbon constitutes a robust and sensitive indicator for measuring the effectiveness of assisted regeneration processes in mined areas. The methodology integrated documentary analysis of PRADs, field surveys recording geomorphological features and vegetation conditions, and soil analyses at two depths, spatialized through interpolation and kriging to identify patterns of carbon stock distribution. Three products were developed: a literature review article on area recovery in the Caatinga and carbon storage; a scientific article presenting empirical results of soil-carbon analysis in mined areas under fallow; and a Natural Regeneration Assessment Protocol designed to guide monitoring actions and support public policy. The results revealed significant weaknesses in the PRADs examined, including generic diagnostics, inconsistencies between licensed areas and the areas actually exploited, and the absence of systematic monitoring. Field campaigns confirmed mining activities in areas without valid environmental licenses and documented exposed soil, erosive processes, low vegetation diversity, and signs of post-extraction abandonment. Soil-carbon analysis showed a performance gradient among the evaluated sites: Marco, Pio IX, and Capivara exhibited higher carbon stocks and greater vertical coherence; Agreste and Jaicós presented intermediate conditions; and Picos showed the lowest values and the greatest spatial fragmentation. The findings partially confirmed the main hypothesis by revealing methodological fragilities and insufficient monitoring in PRADs, and fully confirmed the complementary hypothesis by validating soil carbon as a sensitive and reliable indicator for measuring the effectiveness of assisted regeneration. The study concludes that recovery efforts in the Caatinga require clear protocols, verifiable metrics, and continuous monitoring capable of informing technical decision-making and strengthening the ecological and climatic resilience of the semi-arid region.