The principal aim of the three-year researches of bark beetle fauna in Plitvice Lakes National Park was to assess the population dynamics and abundance of spruce bark beetles, focusing on Ips typographus and Pityogenes chalcographus. These are the two most significant bark beetle species and, when their populations reach outbreak levels, can trigger spruce forest dieback such as that seen in recent years in the forests of Gorski Kotar and Northern Velebit. Three years of monitoring with pheromone-baited flight-interception traps at 13 representative sites established the pattern of catches, used as an indirect measure of abundance. Catches peaked in 2022 and declined in 2023 for both monitored spruce bark beetle species. In addition to this objective, the study encompassed the entire bark beetle assemblage (Coleoptera, Curculionidae, Scolytinae). A total of 32 species were recorded within the Park’s present-day boundaries, representing an increase of 12 species compared with historical records from the 1950s. Two invasive species that are already widespread in this part of Europe are particularly noteworthy: Xylosandrus germanus and Gnathotrychus materiarius. Conversely, Ernoporicus caucasicus and Xyloterus laeve represent rare and noteworthy records. Among the closely related pinhole borers (Curculionidae, Platypodinae), in addition to the expected and widespread oak pinhole borer (Platypus cylindrus), the presence of a very rare Palaearctic relict, the fir pinhole borer (Treptoplatypus oxyurus), was also confirmed in Plitvice Lakes National Park. Native to the Palaearctic, this pinhole borer is considered a relict species and an indicator of the old-growth character of Europe’s beech–fir and fir forests. Outside Croatia, it is currently known from only a handful of European countries: France (the Pyrenees and Corsica), parts of Spain (the Pyrenees), Greece (the Peloponnese), Italy (Sardinia and the pre-Alpine region) and Slovakia (Badín Primeval Forest). In addition to incidental catches made as part of the spruce bark beetle monitoring programme, a series of additional traps was deployed and repeated researches focusing on xylophagous and saproxylic insect fauna associated with dead wood were conducted, yielding some very interesting results. Only those species that indicate a well-preserved forest habitat – specifically, the old-growth character of the faunistically rich beech–fir forests of Plitvice Lakes National Park – are highlighted here: the longhorn beetle Pogonocherus ovatus, the fir jewel beetle Eurythyrea austriaca, the beetles Synodendron cylindricum and Ceruchus chrysomelinus, and two rare click beetles, Lacon lepidopterus and Lacon querceus. In addition to these species, some of which were recorded in this area for the first time, the presence of rare and valuable deadwood indicator species associated with old-growth conditions was reconfirmed, including Rhysodes sulcatus, Cucujus cinnaberinus, Peltis grossa and Peltis ferruginea.

Objava Research of bark beetle and other xylophagous beetle fauna in Plitvice Lakes National Park 2021–2023 pojavila se prvi puta na Nacionalni park "Plitvička jezera".