Notes and new data on the distribution of a non-native oligochaete: Branchiura sowerbyi (Beddard, 1892) in Croatia

Sa？etak The freshwater oligochaete Branchiura sowerbyi is indigenous to southeast Asia, but can be found inhabiting most of Europe. This tubificid was even described for the first time outside of its natural area of occurrence: in the garden of the Royal Botanic Society in London. It has spread over all continents except Antarctica, and in Europe it has been found in 23 countries. The presence of this non-native species may affect other species' relationships in the benthic community and thus have substantial effects on food webs of aquatic ecosystems. Our goal was to present the first comprehensive overview of the distribution of this potentially invasive species in Croatia as a basis for the future monitoring of the species distribution. In Croatia, B. sowerbyi was found for the first time in 1954 in Vara？din’s thermal stream and the following year in the lake of the Botanical garden, Faculty of Science, University of Zagreb. To date, B. sowerbyi individuals were found on 64 different sites in Croatia, mostly occupying the Pannonian Lowland Ecoregion (ER 11) with only two findings in the Dinaric Western Balkan Ecoregion (ER 5)