Danube Rivers Morphology and Revitalization - DANUBEPARKS

Non-native and Invasive speciesFor centuries, European inland waterways have provided opportunities for thespread of non-native aquatic species. At present, a complex network of more than28000 km of navigable rivers and canals connects 37 European countries, creating abiological ‘meta-catcbment’ that encompasses large parts of the continent (afterPanov et al., 2009, quoted by Sommerwerk N. et al., 2010). The Danube Riverbelongs to the Southern Invasive Corridor that links the Black Sea with the North Seavia the Rhine-Main-Danube Canal.At present, 141 alien and cryptogenic taxa (41 fish, 67 macroinvertebrate, 24aquatic macrophyte, 1 amphibian, and 8 parasite species) have been reported for theDRB (www.alarmproject.net). Several non-native species are true invasive speciesthat currently represent prevalent components of the aquatic community: Corbiculafluminea (Asian clam); Anodonta woodiana (Chinese pond mussel); Orconecteslimosus (spinycheek crayfish), and Dreissena polymorpha (zebra mussel) (after Liškaet al., 2008; Graf et al., 2008, quoted by Sommerwerk N. et al., 2010). Newintroductions are constantly recorded (after e.g. LeppilkOski et al., 2002;Arbaçiauskas et al., 2008, quoted by Sommerwerk N. et al., 2010). The Ponto-Caspian Region not only serves as a suitable recipient for non-native species, but isalso a key European ‘donor area’ for alien species.The quantification of non-native species was a key focus of the Joint DanubeSurvey 2 (after Liška et al., 2008, quoted by Sommerwerk N. et al., 2010). There isclear evidence that channel stabilization and construction of artificial banks havefavored the establishment of non-native species. Therefore, restoringhydrogeomorphic dynamics is expected to mitigate the spread of invasive species, aspioneer habitats are less prone to the establishment of non-native species (afterTockner et al., 2003, quoted by Sommerwerk N. et al., 2010).Little is known about the ecosystem consequences of novel communities thatare composed of a mixture of native and non-native assemblages. In addition, weneed to improve our understanding of the interactions of species invasion with otherpressures in order to better manage invasive species in the DRB. It will be importantto apply risk assessment procedures and use those results for priority actions toreduce the rate of aquatic invasions and to combine these actions with awarenessraisingmeasures in water management and the public (after Panov et al., 2009,13