Monitoramento da restauração ecológica de áreas atingidas por rejeito de minério de ferro na bacia do Rio Doce

Abstract

The degradation caused by mining tailings is a serious environmental problem, with impacts on ecosystems, communities, and economies around the world. In Brazil, the Mariana (2015) and Brumadinho (2019) disasters in Minas Gerais illustrate the seriousness of these problems, causing environmental and human damage. Restoring the areas affected by the collapse of the Fundão dam in Mariana, MG, is essential to mitigate the damage and requires an integrated approach involving governments, industries, and communities. This incident has prompted several studies focused on the environmental and social recovery of these regions. This work seeks to evaluate the recovery of ecosystem functions in areas with iron ore tailings, monitored eight years after the Mariana accident, using ecological restoration indicators. The study, conducted in eight areas of the Doce River basin (Mariana and Barra Longa, MG), evaluated thirteen ecological indicators. The results show that restoration is a complex process. The tree stratum showed little improvement in richness and diversity, but the average height of the trees increased. Regeneration was limited by seed scarcity, disturbance, and competition with grasses, although some indicators improved locally. The canopy advanced, and ground cover varied, requiring management to reduce grasses and favor native herbaceous plants. The most relevant indicators were: number of individuals and number of species in the regenerating layer; number of individuals and average height of the tree layer; and percentage of ground cover by grasses. Recent restoration may not have been enough to differentiate between conserved and anthropized areas.