LAUSR

Abstract The caddisfly fauna of the Transcarpathian part of the Pannonian Lowland was poorly studied formerly. Here, we present the results of a six-year survey (2015-2020) carried out in four sampling sites of the Ukrainian part of the Bereg Plain and provide the actualised checklist of this area. Actually, 7346 specimens of 53 caddisfly species were collected. The number of known caddisfly species increased from 13 to 61. Two species Hydropsycheguttata and Parasetodesrespersellus, which formerly were considered extinct in the Pannonian Ecoregion, were detected and another especially rare species (e.g. Cyrnusflavidus) was also recorded. The fauna of the region cover a significant part of both Hungarian and Ukrainian caddisfly fauna. Assemblages of four characteristic habitat types of the region showed significant differences considering their quantitative and qualitative composition, substrate, current, hydrological- and feeding types. The high diversity and natural value of the small lowland watercourses were proven using a new Caddisfly Conservation Index (CCI) calculated, based on vulnerability and rarity of species. The fauna and assemblages showed a unique character mainly independent from large rivers of the region.