Notes on the ground beetle fauna (Coleoptera: Carabidae) of the “Sokolata” Reserve in SW Bulgaria

“Sokolata” Nature Reserve lays between 600–900 m a.s.l. at the southernmost part of the Maleshevska Planina Mountain in SW Bulgaria and covers an area of 219.59 hectares. It has been designated in 1985 with the aim of protecting the mountain’s only ancient Hungarian oak (Quercus frainetto Ten.) forest. Due to the hard accessibility of the terrain, its biota is not well studied, as there are none researches on the ground beetles (Coleoptera: Carabidae).

In this study we present initial data on carabid fauna of the Reserve. In the period 22.V.2024–28.V.2025, we explored a mature old oak-beech forest located at 760–780 m. With the help of 12 pitfall traps operating the whole year, we collected 850 specimens from 15 species and 12 genera. All species could be considered new for the Reserve, and Calathus distinguendus is new for the mountain.

Species richness seems poor, but it shows some interesting peculiarities. Carabid community was characterised with the superdominance of Aptinus merditanus orientalis (69.6% of all specimens). There were three more dominants, but all with a presence less than 10% each: Platynus scrobiculatus serbicus (9.2%), Carabus intricatus intricatus and Tapinopterus balcanicus belasicensis (each with 6.6%). In zoogeographic relation, we found unusual combination, with the European-Asiatic and the Endemic complexes being the most rich in species (34% and 33%, respectively). The most surprising, however, was the ecological structure of the carabid complex. Here, we calculated the largest share of brachypterous species (53%) and zoophagous life-forms (93%), compared with all other regions in Bulgaria studied in this respect. In accordance with these patterns, the majority of the species were forest mesophiles.

We could conclude that the carabid fauna of the “Sokolata” Reserve is of specific composition, reflecting the late successional stage of the forest, and deserves more profound and wider research.