Invasive alien species in Switzerland - Schweizer ...

3 > Crustaceans – Crustacea 65
3 > Crustaceans – Crustacea
Prepared by Rüdiger Wittenberg
It is not possible to draw up a comprehensive list of established alien crustaceans in
Switzerland owing to gaps in knowledge for some groups and some regions. Another
complicating factor is the rapid changes in species composition in the large rivers.
Some new invaders are showing an explosive expansion in their ranges and densities.
Despite these shortcomings, a preliminary list has been compiled using available
information. As with all lists of alien and invasive alien species, it is crucial to update
and add new information about distribution, impacts and management options as it
becomes available. However, this list is believed to be a good basis for future expansion,
since a comparison with neighbouring Austria shows similarities in species and
species numbers.
Table 3.1 summarizes available information on 17 established alien crustacean species
in Switzerland. Six of them are considered to be harmful to the environment. More
information on these species is presented in the Fact Sheets at the end of this chapter.
There is little information available on Daphnia parvula Fordyce (Cladocera) and
Atyaephyra desmaresti (Millet) (Atyidae) and their invasions might be of little significance
for native biodiversity.
The copepod Cyclops vicinus Uljanin is thought to have impacted native species by its
predatory behaviour.
The amphipod Corophium curvispinum (Sars) (Corophiidae) (see Fact Sheet) is a
considerable threat to native ecosystems. This species is an ecosystem engineer and
occurs at fairly high densities. In the Rhine between Basel and Bodensee it was the
species with the third highest number of specimens per square metre, i.e. about 9,200
individuals (Rey and Ortlepp, 2002).
Six members of the family Gammaridae are established alien species in Swiss waters.
Four of these are of Ponto–Caspian origin, while one invaded Central Europe from
south-western Europe and one species came from North America. Of the three species
Echinogammarus ischnus (Behning), E. trichiatus (Martynov) and E. berilloni Catta
only the first-named is known to have a negative impact on the environment (see Table
3.1), while insufficient is currently known about the other species to judge. The American
species Gammarus tigrinus Sexton may change the food web after invasion. Two
Dikerogammarus species have invaded Switzerland, D. haemobaphes (Eichwald) and