Successful translocation of the Transylvanian Bavius Blue - Pseudophilotes bavius hungarica (Diószeghy, 1913) (Lepidoptera, Lycaenidae) in Romania, for increased protection and conservation

Pseudophilotes bavius ​​is a butterfly species protected by the EU Habitats Directive. The subspecies P. bavius ​​hungarica , known by the vernacular name Transylvanian Blue, is endemic to the Transylvanian Plain (Transylvanian Plateau) in Romania. Its distribution is limited to dry grasslands on steep, south-facing slopes, always in association with Salvia nutans . Unfortunately, many of the extant populations of P. bavius hungarica are threatened with extinction due to overgrazing by sheep, abandonment of grasslands and afforestation. In order to safeguard this emblematic species, an attempt was made to colonise another suitable habitat patch over 100 km away from the donor sites. Only one year after the translocation of 11 females, a viable core population was formed. In order to strengthen the core population, in 2024, a further six females were translocated. The newly-formed population will increase the resilience of the subspecies and shows a way forward in protecting highly localised, endemic taxa in Romania. The creation of a nature reserve with special protection and conservation measures in the translocation area and the commitment of local stakeholders will ensure the maintenance of the Transylvanian Blue in Romania.