Peat bogs are specific wetland habitats where mosses often play an important role. The Trstenik peat bog is threatened by vegetation succession and drying of the peat bog. In this study, ground beetles (Carabidae) were used as indicators of habitat changes. The objectives of this study were: i) to determine differences in the composition and structure of ground beetle communities in three habitats on the Trstenik peat bog, ii) to determine the influence of environmental factors on the spatial distribution of ground beetles, iii) to define peat bog conservation measures. Ground beetles were collected using pitfall traps. A total of 44 species and 1551 individuals were collected. All measured indices of ground beetle communities were lowest in the central part of the bog but did not differ significantly from the parameters in the successional part. Conversely, significantly higher values were recorded at the forest edge compared to the other two studied habitats. In the peat bog, the greatest impact on the composition of ground beetle communities had the increased presence of the herb layer and soil temperature values, and, particularly in the central part, increased soil moisture and pH. At the forest edge, the abundance of the tree layer played a significant role. The results of the study indicate progressive vegetation succession in the central part of the peat bog, but the discovery of indicator ground beetle species suggests the existence of typical peat bog conditions. Therefore, measures for habitat restoration are proposed.