The species diversity of ground beetles (Carabidae) was studied in the meadow ecosystems in the center of European Russia (Nizhniy Novgorod region and the Republic of Mordovia). Seventeen localities were studied. All meadow biotopes were divided into four types: dry meadows, dry meadows adjacent to forest shelter-belts, wet floodplain meadows, and floodplain meadows affected by livestock grazing. The highest species diversity was in dry meadows adjacent to forest shelter-belts (65 species) and wet floodplain meadows (62 species). The lowest number of species was in floodplain meadows affected by livestock grazing (24 species). Forty ground beetle species have been identified in dry meadows. Wet floodplain meadows had the highest Shannon's index, and the lowest Simpson index. The ground beetle fauna had high values of the Simpson and Berger-Parker indices in dry meadows. Only two species dominated in dry meadows, while four to seven species dominated in other habitats. According to the Jaccard similarity index, the most similar species composition of ground beetles was in dry meadows and dry meadows adjacent to forest shelter-belts. By reducing the number of species and specimens of ground beetles, trampling has a great effect on the fauna of floodplain meadows affected by livestock grazing.