Butterfly fauna (Lepidoptera: Papilionoidea) of Svilaja Mountain, Dalmatia

Svilaja is a 30 km-long mountain range in the Outer Dinarides in the hinterland of northern Dalmatia, between the rivers Cetina and Čikola. It has never been the target of systematic butterfly surveys and its fauna remained completely unknown. During our surveys from 2019 to 2022, we recorded 112 butterfly species at 37 sites. The butterfly richness of the Svilaja Mountain is higher than that of the Mosor and Kozjak Mountains nearer to the coast, but similar to that of the Biokovo Mountains and lower than that of the nearby, much larger Dinara Mountains. However, the biogeographical composition of the mountains compared is similar, with dominant Euro-Siberian and Euro-Oriental faunal elements, but an obvious decrease in the number of montane species in all other mountains compared to the Dinara Mountains. New records are discussed for some species for which there is little information for Croatia or Dalmatia, such as Carcharodus orientalis, Pyrgus carthami, Tarucus balkanicus, Aricia artaxerxes, Polyommatus ripartii, Melitaea ornata, Melitaea athalia, Coenonympha rhodopensis and Hyponephele lupina. Although most of Svilaja Mountain is part of the Natura 2000 network, many of the sites with high conservation value are located outside the area. Overall, the abandonment and overgrowth of grasslands present the most imminent threat to butterfly diversity in the region.