Alien Crustacea in Polish waters – Amphipoda

Among ca. 750 species of Crustacea recorded from Poland, 18 representatives of 5 orders of macro-crustaceans have been identified as alien species that have invaded or have been introduced to Polish waters. Out of 44 freshwater, brackishwater and semiterrestrial species of Amphipoda occurring in Poland (not counting several stygobiotic species), 8 species from three families may be included in this group. They are Corophiidae: Chelicorophium curvispinum (=Corophium curvispinum), Gammaridae: Gammarus roeselii, G. tigrinus, Chaetogammarus ischnus (=Echinogammarus ischnus), Pontogammaridae: Dikerogammarus haemobaphes, D. villosus, Pontogammarus robustoides and Obesogammarus crassus. It is noticeable that most of them (C. curvispinum, C. ischnus, D. haemobaphes, D. villosus, P. robustoides, O. crassus) are of Ponto-Caspian origin, one species was introduced from North America (G. tigrinus), and one from south-eastern Europe (G. roeselii). All the species listed above have spread widely in Poland, in large rivers and artifical reservoirs (Chelicorophium curvispinum, Dikerogammarus villosus, D. haemobaphes, Pontogammarus robustoides, Gammarus tigrinus) or in medium sized rivers (Gammarus roeselii), in brackish coastal waters (Obesogammarus crassus) or both in fresh and brackish waters (Gammarus tigrinus, Pontogammarus robustoides). In most places they successfully outnumber or even completely replace native amphipod species. This paper presents data on biogeography, history, biology and ecology of alien species, as well as the consequences of their invasion in Poland with an extended bibliography and references to other European countries.