A sensor for water quality
The stream flea crayfish is 2021 ambassador for diverse, clean streams. Where it occurs in large numbers, the stream is healthy. The choice of the stream flea crab is also a tribute to the countless small, inconspicuous animal species that keep the ecosystem moving in the first place.
If you turn over a washed-up leaf or stone in a clean stream, you will almost certainly discover one or more specimens of the stream flea crab (Gammarus fossarum). The crustaceans, which are barely the size of a fingernail, hurry away in a sideways position to hide again.
Key position in the food chain
The stream flea crayfish, the animal of the year 2021, is the most common species of flea crayfish in Switzerland. It colonizes almost all parts of the country from the lowest altitudes up to about 1300 meters above sea level. Only in Ticino and in some southern valleys the species seems to be missing. Stream fleas feed on dead aquatic plants and fallen leaves. In clean, rather cool streams, thousands of animals can cavort on a single square meter. This makes stream fleas an important food source for fish and other aquatic animals.
Water quality indicator
Freshwater fleas react sensitively to water pollution. For this reason, they are also used as indicators of the cleanliness of water bodies. In view of the current problems with pesticides and fertilizers, this attracts increased attention to these small stream dwellers. After all, it is the smaller streams in agricultural areas that are particularly affected by pollutant inputs. This harms the crayfish and, because of their central role in the ecosystem, indirectly also fish and other species.
Pro Natura renaturalizes rivers, brings culverted streams to daylight and protects springs. This creates new water worlds for stream fleas and all other water species throughout Switzerland.
Source: Pro Natura
Current book about the amphipods of Switzerland
The project based at Eawag and the University of Zurich "Amphipod.ch" has been investigating the diversity and distribution of amphipods in Switzerland since 2014. As part of this project, over 200,000 individuals from 2238 sites were determined and studied. As a result of this work, a comprehensive overview in the form of a monograph was published for the first time in autumn 2019 (Altermatt et al. 2019). The latest volume in the Fauna Helvetica series includes a richly illustrated identification key, species monographs with ecological and faunistic explanations, and distribution maps of all psyllid species in Switzerland. Thus, the book (ISBN: 978-2-88414-045-4) provides for the first time a broadly supported basis for the use of psyllids in biodiversity analyses, in aquatic ecology, in water protection and in ecotoxicology.
Altermatt, F., R. Alther, C. Fišer, and V. Švara. 2019. amphipoda (amphipods) of Switzerland. Fauna Helvetica 32. info fauna CSCF & SEG, Neuchâtel, ISBN: 978-2-88414-045-4.
