The red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), and ground-dwelling ant species native to Georgia were observed and studied in tree-canopied and open uncanopied habitats in two state parks in central Georgia. Population density, native species diversity, and interactions of native species with each other and with the invasive S. invicta were determined and compared in the two habitats. Sampling methods included pitfall traps, baits, collection of leaf litter, and visual searches. In comparison to the open uncanopied habitats, red imported fire ant population density was lower in tree-canopied habitats, and native ant species diversity was greater in the canopied habitats. We also observed native species competing with red imported fire ants more intensely in canopied than in open habitats primarily by foraging activity and by predation of S. invicta reproductives. Our results suggest that native ant species can suppress S. invicta population numbers and density and that competition by native ant species should be considered in approaches of managing red imported fire ant.