Fauna epígea como bioindicadora de qualidade do solo em áreas reflorestadas após mineração de bauxita no Oeste do Pará

Abstract

Mining is an economic activity that contributes to the place where it is developed, as itprovides job creation, invests in the health and education sectors, in addition to being a sector responsible for generating taxes. However, the high magnitude impacts that mining operations generate on the environment, such as deforestation and eliminationof the upper layers of the soil, must be considered. Thus, altering the natural landscapeand modifying the habitats of microorganisms that perform trophic functions. In this context, the objective of this work was to characterize the diversity of epigeal fauna organisms in reforested areas under different nucleation methods, after bauxite miningin the Municipality of Juruti, in the Lower Amazonas Mesoregion, West of Pará. Threeareas with different forest recovery times and a reference area were selected, namely:(A1) area reforested in 2018; (A2): area reforested in 2015; (A3): area reforested in 2012, and (A4) area representative of the characteristics evaluated before the mining process (Forest area). To collect epigeal fauna, traps were installed in the month of May, lasting 5 days in the field. A “pitfall” type trap was used, consisting of plastic containers 11 cm in diameter and 11 cm high, buried at ground level, covered with disposable aluminum packaging, supported with toothpicks 10 cm from the trap opening, to protect from rain, prevent individuals from deteriorating and traps from filling with water. Each trap contained approximately 170 mL of 70% alcohol and 3 drops of neutral detergent, to preserve the animals during the sorting process. In the laboratory, the contents of the traps were placed in bottles containing 70% alcohol, subsequently, identification was made regarding taxonomic groups with the aid of a binocular magnifying glass. In terms of abundance, no differences were observed between the areas, however, area A2, with the nucleation technique using topsoil + planting of seedlings + gallaria in 2015, presented a greater number of organisms. As for total wealth, there was no difference between the recovered areas. For the Shannonand Pielou indices, higher values were found in Area 1, due to the greater diversity anduniformity of the epigeal fauna. Thus, the use of epigeal fauna proved to be efficient asa bioindicator of soil quality, since the areas studied showed richness values similartothose of the reference area.