Rapid range extension of the Ponto-Caspian amphipod Dikerogammarus villosus in France: potential consequences

Non-indigenous species are increasingly recognized as altering local com- munities in newly colonized areas. In some north European freshwater systems, the Ponto-Caspian invasive crustacean Dikerogammarus villosus (Amphipoda) is im- plicated to have such an effect, with general monitoring of its progress and general im- pact required. The present study contributes to this monitoring. D. villosus was ob- served in 2003 in all the major French rivers prospected (i.e. Rhine, Meuse, Moselle, Sao ne, Rho ne, Seine, and Loire), a European region previously overlooked for its co- lonization. This species was also detected in some tributaries of the rivers Sao ne and Seine, and in Geneva Lake. The …