In the past few decades, there has been a sharp decline in specialised and rare species of both ground beetles (Carabus) and great diving beetles (Dytiscinae) throughout Europe. Our aim was to determine the distribution trends of chosen species and their conservation status in Slovenia. Based on historical and recent data, distribution maps for each species have been made. Extensive data for 25 species of genus Carabus and 16 species of diving beetles were analysed. The reduction in distribution area sizes was used to evaluate the decline of each species in Slovenia and for assigning them to different categories of threat status. A significant number of species from both beetle groups are in decline; however, due to destruction of suitable water habitats, the disappearing rate of diving beetles is higher. Only 3 species from each of the chosen groups of beetles are currently on the Red list of threatened species in Slovenia, and based on our results, at least 14 species of ground beetles and 11 species of diving beetles should be added to the list. Open habitat species of ground beetles, ground beetles that are dependent on mature, unmanaged forests, and diving beetles that prefer peat bogs or small, strongly vegetated ponds, were found to be the most endangered. The difference between stenotopic and eurytopic species was significant only in the case of diving beetles. A few species from both groups of beetles have already disappeared from Slovenia in the last few decades, therefore intensive ecological studies of the remaining species and immediate effective conservation strategies are essential.
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