This study aimed to evaluate the ant fauna in three different land-use systems: pasture, eucalyptus plantation and secondary forest, in southeastern Brazil. The ant fauna was collected with standardized pitfall traps. Forty-seven ant species were collected, belonging to 24 genera and six subfamilies. The total ant species richness was significantly higher in secondary forest (29 species) and eucalyptus plantation (25 species) when compared to the pasture (17 species), with no significant difference between the secondary forest and eucalyptus plantation. The species composition differed significantly between the three land-use systems. The frequency distributions of ant guilds in eucalyptus plantation and secondary forest differed significantly from the frequency in the pasture. The results demonstrated the importance of natural forests for the conservation of biological diversity of the Atlantic Forest, but they also indicated that eucalyptus plantations, with native understory plants, can harbor considerable ant diversity.
