Cordulegaster heros is a central and southeastern European endemic taxon ranging from Austria and Slovakia to a large part of the Balkans. The species was only described in 1979 and only in the last two decades its distribution started to become clear (Adamović et al. 1992, Bedjanic and Salamun 2003, Blaskovic et al. 2003, Bulankova and David 2003, Kotarac 1997, Uboni et al. 2007, Janský and David 2008). Its eastern limit in Romania is unknown and it might even go as far east as the Ukraine. It is locally common but scattered because of its specific habitat, mostly shaded rivulets in mountainous areas. In the south of its range, this species is currently decreasing due to climate change, rainfall deficit, spring capture and desiccation of streams.