The freshwater bryozoan Pectinatella magnifica (Leidy, 1851) in the Austrian Danube: first evidence in the upper Danube basin.
The phylactolaemate Pectinatella magnifica is a rapidly spreading freshwater bryozoan originating in North America that has been observed in several countries, particularly in Europe, in the 19th century. P. magnifica forms massive compound colonies whose ecological effects have been poorly studied, but as suspension feeders they likely impact nutrient cycling and food web structure. The Danube is one of the largest rivers in Central Europe and along with its connection to the Rhine, represents a major route for non-native and invasive species spreading from the North Sea to the Black Sea. P. magnifica has been previously recorded in the Middle Basin of the Danube at Budapest and further downstream up to the Danube Delta. In this study we first report P. magnifica from the Upper Danube Basin, in the vicinity of Vienna (Austria). It appears that P. magnifica has previously been overlooked and that it invaded the Upper Danube either via river systems of the Rhine in Western Germany or within the Danube basin via the Czech Republic towards Austria. Alternate dispersal routes are possible via statoblasts attached to waterbirds. As well as the first record in the Upper Danube, this study is the first report of the species in Eastern Austria.