Estrutura da Comunidade de Formigas (Hymenoptera: Formicidae) em pastagens com diferentes tipos de manejos

Abstract

One of the main threats to biodiversity of the Cerrado is its conversion of natural areas into agriculture and livestock. Different types of management in pastures can cause impacts both on soil biodiversity, and in structure in the community of the ants local. Ants are a dominant group of insects commonly used as bioindicators in environment with some type of disturbance. Therefore, we evaluated how different types of the management affect the community (richness, abundance and composition) of the ants in pasture. The collection was carried out in 24 pasture areas, using pitfall traps in the rainy season, in the months of December and January. In order to characterize the different types of management in pastures, six environmental variables were measured: soil compaction, grass cover, tree density, pasture age, cattle density and time of stay in the cattle. Only the variables associated with the structure of the vegetation were significant, being that the tree density affects the richness, abundance and composition of the ant fauna; grass cover affects the composition; and pasture age affects the richness. These results suggest that a greater trees density enables the creating new habitats and microclimates, consequently bigger richness, abundance and a composition different of ants. Similarly, the grass cover seems to influence the composition of the species so that pastures with higher grass cover tend to have a more similar fauna than those with lower grass cover. Pasture age was important for ants richness, in which older pastures tend to have greater ants richness. With these results, the variables associated with management are not important to the ant community. Only those associated with vegetation structure were important for the ant fauna in pastures, allowing the adoption of management techniques that respect this structure, being more protective of the local community.