1.Several factors influence species distribution within communities, with ecological filters playing a particularly significant role by shaping morphological, physiological, and behavioral adaptations. Seasonal changes in environmental conditions—such as light incidence, temperature, and humidity—can favor species capable of foraging under varying conditions or in different strata.2. Ants are excellent models for studying how ecological filters structure communities throughout the year, as they exhibit traits that enable occupation of a wide range of microhabitats. Two such traits that may reflect responses to environmental filters are body size and color. In this study, we investigated how ant distribution varies between soil and vegetation across two seasons, and how these patterns relate to ant morphology in an ecotonal area between the Amazon and Cerrado biomes.3. Ants were collected using pitfall traps placed in the soil and on the lower vegetation, and we measured the size and color of representative individuals from each species. We recorded 2,659 occurrences, representing 237 species, 53 genera, and 8 subfamilies. Species richness was higher during the dry season, particularly in the soil. Species turnover was the main component of beta diversity, but this varied seasonally. During the rainy season, many soil-dwelling ants shifted to the vegetation, increasing the nestedness component in cross-strata comparisons. Larger ants were more common in vegetation, while smaller ants predominated in the soil. Additionally, darker individuals were more frequent in vegetation during the dry season.4.These findings indicate that ant community composition in the soil and lower vegetation are not stable year-round. Instead, foraging activity and species presence are structured by seasonal climatic parameters. This study offers insights into how ant diversity responds to environmental filters in a transitional ecosystem, emphasizing the importance of seasonal dynamics and vertical stratification in shaping community assembly.