Classification of Water Bodies of the Lower Hron River Based on Chironomid Assemblages (Diptera: Chironomidae)

Abstract: Chironomid assemblages of the lower Hron River and eight side arms were studied. The aim was to investigate if potamon types could be recognized and distinguished by chironomid assemblages. Therefore, 10 sampling sites were classified into 4 potamon types: eupotamon, parapotamon, plesiopotamon and paleopotamon. Within the eupotamon type, the main channel and the dammed channel section were compared. In total, 66 chi-ronomid taxa were recorded in 2000–2002. In the main channel, rheophilic and rheobiontic taxa predominated, especially the subfamilies Tanypodinae and Orthocladiinae. The most frequent taxa recorded in the dammed sec-tion of the Hron River belonged to the tribe Chironomini. A characteristic feature of the studied side arms was the absence of rheophilic chironomids. The highest taxa richness was found in parapotamon type arms in comparison with the plesiopotamon and paleopotamon. Cluster analysis based on presence/absence data of chironomids sep-arated the sites of the main channel (eupotamon) and side arms directly influenced by the main channel (para-potamon, plesiopotamon), from the side arms without direct influence of main channel (paleopotamon). Further-more, eupotamon sites were well separated form the parapotamon and plesiopotamon type arms