Eficiência da recuperação ambiental de áreas antropizadas pela mineração de ferro do Complexo Carajás - PA

Abstract

Mining activities have a direct influence on economic development, which directly affects the gross domestic product (GDP), mainly in developing countries. The environmental interference provided by the mining activities can vary in intensity according to the mineral exploited, but they are always punctual activities. This study was conducted in the mineral province of Carajás, PA, in areas revegetated post mining iron ore, and to evaluate the processes of vegetation arising from revegetation of barren slopes, starting from the initial hypothesis that signed the revegetation of slopes of waste in the mining of iron using cocktails of seed species in the rainforest and savanna Metalófila can act as facilitators of natural succession and conditioners as the substrate. The second hypothesis is that signed the removal, storage and return of surface soil organic horizon ("topsoil") after the operation by open pit mines have an essential role in the revegetation process, because they already provide quantitative and qualitative characteristics that reflect the communities previously existing in the area. In this work were highlighted four areas of study, three areas undergoing revegetation and an area with the presence of primary forest. The variables analyzed were phytosociology, photosynthetically active radiation, chemical quality of the stock of litter, soil fauna and soil fertility. The results indicate that the revegetation processes used, promoted the formation of a plant community which facilitates the process of succession over time, as many of the species used in the cocktail of seeds of the CCI and workshop areas are being replaced by species more adapted to conditions of each site. In the area called Hoppe, the herbaceous species that colonized the area are being replaced by shrub and tree species. The quality of the provided information able to litter cluster areas of studies according to the nutrients present in the litter, the areas being divided into Workshop CCI and the concentrations of lignin, cellulose, P and Mg, while areas were grouped Hoppe and Mata as a function of P and N fractions present in the twigs and leaf litter. But the use of soil fauna indicated that the groups Collembola and Formicidae will be extremely important for monitoring the quality of sites over time. From these results it was concluded that the use of biotic and abiotic indicators in studies of recovery of mined areas should be thoroughly studied and documented, they offer attributes able to understand developments in the recovery process.