Monitoring of the Cranberry Blue Plebejus optilete (Knoch, 1781) (Lepidoptera: Lycaenidae) in the Pohorje Mountains | Monitoring borovničevega mnogooka Plebejus optilete (Knoch, 1781) (Lepidoptera: Lycaenidae) na Pohorju

Inglés. The Cranberry Blue (Plebejus optilete) is limited to the crests of the western Pohorje Mountains in Slovenia, where it occupies six separate sites. The species is confined to rich flowering montane grasslands on the silicate ground with the association Homogyno-alpine-Nardetum and high proportion of blueberries and Common Heather. For the favourable state of the habitat, European Goldenrod and Mountain Arnica are also important as the main source of nectar for adults together with Common Heather. During the six years of monitoring with the transect method, pronounced fluctuations were observed, but in almost all sites a negative trend in abundance of adult specimens was observed. The highest diversity of butterflies was recorded on the Kope transect, where the habitat of the Cranberry Blue is best preserved. The species is endangered by the reduction and deterioration of its habitat due to overgrazing, inadequate agricultural use and inappropriate development of tourism. In the long term, the potential threat to the species is also climate change. The management guidelines are given for ensuring permanent conservation of the habitat and the population of the Cranberry Blue in the Pohorje Mountains.

Esloveno. Borovničev mnogook (Plebejus optilete) je v Sloveniji razširjen le na ovršnem delu zahodnega Pohorja, kjer živi na šestih ločenih območjih. Vrsta je vezana na vrstno bogata gorska travišča na silikatni podlagi tipa volkovje (Homogyno-alpine-Nardetum) z visokim deležem borovnic in jesenske vrese. Za ugodno stanje habitata sta pomembni še navadna zlata rozga in arnika, ki sta poleg jesenske vrese glavni vir nektarja odraslih osebkov. V šestih letih monitoringa s transektno metodo smo ugotovili izrazita medsezonska nihanja, vendar skoraj na vseh ploskvah tudi trend upadanja številčnosti odraslih osebkov. Največja pestrost dnevnih metuljev je bila zabeležena na transektu na Kopah, kjer je habitat borovničevega mnogooka najbolj ohranjen. Vrsto ogrožata zmanjševanje in slabšanje življenjskega okolja zaradi zaraščanja travišč, neustrezne kmetijske rabe in neprilagojenega razvoja turizma. Dolgoročno so potencialna grožnja vrste tudi klimatske spremembe. Podane so upravljavske smernice za zagotavljanje trajnega ohranjanja življenjskega prostora in populacije borovničevega mnogooka na pohorskih planjah.