<p>Habitat heterogeneity, ecological interactions, and abiotic characteristics are the factors that structure ant assemblages in terrestrial ecosystems. The anthropogenic actions of degradation and restoration have increased the scenarios and possibilities of response patterns in the face of environmental changes. This study aimed to analyze the community structure of leaf litter ant fauna in areas of the Atlantic rainforest and pasture undergoing the process of ecological restoration in two sampling periods. Data were collected bi-monthly from the installation of pitfall traps, installed from April 2015 to August 2016 and April 2017 to August 2018. The analyses were carried out based on the parameters of community structure and relationships with the microclimate. A total of 2,998 specimens were distributed across seven subfamilies, 26 genera, and 125 species/morphospecies. No differences were observed in species richness between native forest and pasture with nucleation techniques. Significant differences in species composition were observed between native forests and pastures with nucleation techniques. Microclimate was an essential determinant for structuring ant assemblages, discriminating regions where the arboreal component was present and absent. The number of unique species in the native forest area demonstrates the need for fragments in sound conservation stages. Our results support leaf litter ant fauna as a bioindicator for monitoring the restoration of areas degraded by pastures in the Atlantic Forest in Southern Brazil.</p>