Four Ponto-Caspian and one American gammarid species (Crustacea, Amphipoda) recently invading Polish waters

Abstract

The paper discusses recent drastic changes in the composition of Polish gammarid fauna, that occurred at the end of 20th century. This change was caused by the invasion of five alien species - four of Ponto-Caspian origin (Dikerogammarus haemobaphes. D. villosus, Obesogammarus crassus and Pontogammarus robustoides) and one of American origin (Gammarus tigrinus). Probable invasion routes are presented.