Areas Degradated by Extraction of Clay and Revegetated with Acacia mangium and Eucalyptus camaldulensis : Using Soil Fauna as Indicator of Rehabilitation in an Area of Brazil

Abstract

Biological indicators of soil quality can be utilised to evaluate the degree of recovery of a degraded area. The aim of this work was to evaluate the edaphic fauna, in areas degraded by the extraction of clay and revegetated with Acacia mangium and Eucalyptus camaldulensis both in monoculture and intercropped systems. Samples of soil and litter were collected in August 2006, utilising a square wooden probe. The samples were placed in a battery of Berlese-Tullgren-type extractors, and after 15 days, the extracted organisms were collected in glass tubes containing a 50% alcohol solution. The specimens were transferred to a 70% alcohol solution in the laboratory, and the organisms were screened with the help of a binocular loupe and separated into large taxonomic groups. Results showed that the type of plant cover influenced the soil fauna density as well as diversity. The acacia-eucalyptus intercropping was the system that gave better distribution of organisms within each group (equability) and consequently greater diversity, compared to monocultures and to the area with spontaneous vegetation.