Comunidade de artrópodes do solo como bioindicadores do processo de restauração em áreas afetadas por rejeito de mineração de ferro

Abstract

The Fundão dam, located in the Minas Gerais municipality of Mariana, Brazil, failed in November 2015, releasing around 43 million m³ of iron mining tailings into the environment. A large part of the tailings was deposited in the riparian zone of the Gualaxo do Norte River, which is located downstream of the Fundão dam. This region has been in the process of ecological restoration since the beginning of 2016 and with this process, a gradual return of ecosystem components is expected, including soil arthropods. These organisms tend to reflect environmental conditions as they relate to vegetation, soil, and litter. In addition, arthropods have several morphological and ecological characteristics that support their use as bioindicators. In this context, this dissertation aimed to evaluate the response of the arthropod community to the restoration process in the riparian zone of the Gualaxo do Norte River. The dissertation was divided into two parts, the first presents a bibliographic reference contextualizing the Fundão dam failure, its environmental impacts and the restoration process. The dissertation was separated into two parts, first part presents a bibliographic reference contextualizing the Fundão dam failure, its environmental impacts, and the restoration process. In addition, the reference provides information about the arthropod community that inhabits the soil and supports its use as a bioindicator of the restoration process. In the second part, we present the article product of the dissertation project, in which we used pitfall traps to collect arthropods and evaluated the composition, potential indicator species, species diversity, and abundance of functional groups as response variables of the arthropod community. Environmental variables related to vegetation (understory density), litter (weight and diversity), and soil (physical, chemical, and biological attributes) also were used as explanatory variables for the richness of arthropods. To compare the results, we used a riparian zone with native riparian forest as a reference and it was possible to verify that the riparian zone of the Gualaxo do Norte River, which is in the process of restoration, still has a different species composition, but a higher species richness, which may be related to colonization by species from adjacent areas. Through the relationship of environmental variables with the composition and richness of species, it was possible to verify which environmental variables had a significant effect and which can be worked on to stimulate the re-establishment of the arthropod community. It is expected that results obtained in this dissertation can help in the monitoring and development of different strategies in the restoration process of the riparian zone of the Gualaxo do Norte River, such as the identification of environmental variables that interfere in the arthropod community and can be managed to aim at its re-establishment. In addition to contributing not only to the restoration of the arthropod community, but of the components of the ecosystem as a whole.