Fauna do solo como bioindicador no processo de revegetação de áreas de mineração de bauxita em Porto Trombetas-PA

Abstract

Bio-indicators are frequently used for environmental quality studies, monitoring of degraded areas and recovery processes, because they are intimately associated to specific landscape characteristics and respond to environmental changes by alterations in vital functions. In this sense, the study of the behaviour of edaphic organisms can contribute significantly to the evaluation of the environmental quality and to strategies and processes aiming the recovery and rehabilitation of areas affected by some type of degradation. This study aimed monitoring the colonisation by the soil fauna community of areas degraded by bauxite mining activities and revegetated with a mixture of native and leguminous species in the municipality of Porto Trombetas-PA, Brazil. Material was sampled in the years 2000, 2002, 2003, 2004 and 2008, in a chronosequence of regenerated areas of bauxite waste covered or not with topsoil, and in plantings in former bauxite tailing ponds. The individuals were captured in pitfall traps and separated in the Laboratory of Soil Fauna of the Embrapa Agrobiologia Research Centre. The evaluated parameters were abundance, richness, Shannon index, Pielou’s equitability index and the colonization patterns of fauna groups. The soil fauna profiles were obtained by nonmetric multidimensional scaling (NMS) ordination, and the response of soil fauna community was evaluated using principal response curves (PRC). The results showed that the time from planting and the nutrient availability were determining factors during the environmental recovery of the system, especially in the bauxite waste areas revegetated in 1984, 1992 and 1994, and in the tailing pond areas that received higher amounts of fertilizers. In these areas, the vegetation development caused a better colonization and structuring of the soil fauna community, increasing its diversity and reestablishing the ecological processes.