Análise da restauração de áreas de campo de altitude com gramínea Aristida sp. após lavra de bauxita

Abstract

Mining is one of the human activities that has major impacts over the natural resources and that highly affects the ecosystems' resilience. Many mining areas are not effectively rehabilitated to re-establish a relevant part of their biodiversity and environmental services. Thus, the main goal of this study was to evaluate the soil traits, soil loss and vegetation of altitude grasslands, through chemical, physical analysis, percentage of vegetation cover, and soil loss in areas under the recovery strategy of Altitude Grasslands from Alcoa Corp. in Poços de Caldas - MG. The areas were submitted to recovery with the grass species Aristida sp. in different periods - 2011, 2012, 2013, 2015 - and in two different areas of reference: one opened area and another with native vegetation (without mining intervention). Soil samples were collected, with a total of 15 recurrent samples for each sample area, in order to analyse the physical and chemical parameters, porosity and density in a laboratory, and evaluate the percentage of vegetation cover. Twelve monitoring plots were installed in representative points: two with 0-20% and 20-40% slopes in each planting age and two in each one of the reference areas. From them, samples were gathered to hydraulic conductivity tests, that could provide precipitation and soil loss data. The statistical analyses were performed with Principal Component Analysis (PCA) to select the variables with higher percentage of variance of each component. Afterwards, they were submitted to a linear regression analysis through General Linear Model (GLM), and, in order to determine the behaviour of the variable across time, linear and squaring functions were used. The results indicated that the longer the recovery time, the closer the areas can be from the reference native area in vegetation cover and soil loss.