Dung beetles play an important role in the sustainability of agroecosystems by providing various ecosystem services. The spatial distribution of species can be affected by vegetation structure and soil type at a small scale. Our study was conducted in a cattle ranch in which there were two grassland areas with different types of soil (humid silty clay vs. dry clay) and a plantation of Eucalyptus L'Hér. (Myrtaceae). The aim of this study was to analyze variations in diversity and structure of dung beetle assemblages by considering the feeding guilds (coprophagous, necrophagous, and generalists) and functional groups (paracoprids, telecoprids, and non-nester dwellers) among the three mentioned habitats. Nine pitfall traps baited with cow dung, horse dung, or carrion were placed simultaneously at each site every two weeks over the course of a year. Coprophagous species dominated over necrophagous and generalist species in abundance and biomass in each habitat. The highest species richness occurred in the pasture on humid silty clay soil and the lowest in the Eucalyptus plantation. Abundance and biomass of paracoprids were highest in the pasture on humid silty clay soil, while non-nester dwellers dominated in the pasture on dry clay soil and the Eucalyptus plantation. Large paracoprids were almost non-existent in the pasture with dry clay soil. In the Eucalyptus plantation, the marked reduction in species richness, particularly of telecoprids and paracoprids, the increase in species dominance, and the absence of rare species were clear indicators of an adversely affected environment.