The current distribution of the endangered and protected Carabus hungaricus Fabricius, 1792 (Coleoptera: Carabidae) in Bulgaria

Carabus hungaricus Fabricius, 1792 (Coleoptera: Carabidae) is a zoophagous, mesoxerophilic, stenotopic steppe species and endangered everywhere across its highly fragmented distribution range, from Central Europe to Eastern Siberia. The known range of the species in Bulgaria is limited to the western part of the Sofia Basin and, in particular, the neighbouring parts of the Western Stara Planina Mountains. The presented results were obtained during a three-year study (24 May 2021–10 December 2023) using 252 pitfall traps, set in 42 sample plots situated in xerophytic landscapes near the Sofia Basin and similar regions in central–western Bulgaria. The studied areas represent the southernmost limits of the distribution of the steppe fauna in Eurasia and, in Bulgaria, C. hungaricus is only found there (and not in all of them). Carabus hungaricus was established in only seven of the sampling sites, with a total of 198 specimens. These sites are located in the Chepan Planina and Tri Ushi Mountains, both in the range of the Western Stara Planina Mts. Our results add four new points to the distributional map of C. hungaricus in Bulgaria and can be used to update the information regarding its altitudinal limit (the species was so far known from between 500 and 800 m a.s.l), elevating it to 1180 m, under the top of the Chepan Planina Mt. The species will probably be found at the very top (Petrovski Krast Peak, 1206 m) as well. The species was not found in the Western Forebalkan (the “exit” of the Iskar River Gorge) or in the Kraishte Region (Lyubash and Golo Bardo Mountains). Generally, our results confirm that the distribution of C. hungaricus in Bulgaria seems to be limited to within the boundaries of the Natura 2000 Site of Community Importance (SCI) BG0000322 “Dragoman”, but the discovery of new localities indicates that there are still gaps in our knowledge.