Recent findings and ecological notes on riffle beetle Potamophilus acuminatus (Coleoptera: Elmidae) in Serbia

Abstract

Potamophilus acuminatus is regarded as a rare European riffle beetle, which is considered as endangered in many countries. The paper presents new data on the distribution and ecology of P. acuminatus in Serbia. During the Regular Annual Monitoring Sampling in the period 2011-2013, the presence of P. acuminatus was confirmed at eight sampling sites situated at six rivers: Lugomir, Ljudska Reka, Vlasina, Ibar, Zapadna Morava and Velika Morava. Particularly important are the records from the potamal zone of the Velika Morava River of this primarily hyporhitral and mesorhitral taxon. The specimens were found at the edges of stones, under broken tree trunks, rotting branches and stumps submerged in water. The species is absent in reservoirs, lakes and artificial water bodies in Serbia, as well as in lowland parts of the country (Vojvodina, Pannonian Plain). It is very rare and scarcely distributed in lowlands (except Pannonian Plain) and in river valleys in submountain regions. The rarity of findings and low number of the collected specimens are in accordance with literature data and previous records in Serbia. Recording P. acuminatus in the relatively polluted Velika Morava River suggests its somewhat broader ecological valence, particularly regarding tolerance to organic nutrients. This species, being more sensitive to pronounced negative human impacts on its aquatic habitats (larger lowland and submountain rivers) in this region, requires particular attention in future investigations.