Our waters are diverse habitats for numerous animal and plant species. But biodiversity is on the decline: more than half of fish species are threatened with extinction.
Rhone, Rhine, Inn – some of the most important rivers in Europe have their source in Switzerland, which is why it is sometimes known as the reservoir of Europe. Rivers and standing bodies of water, including around 1,500 lakes, make up four percent of the country’s total area. This habitat is home to a large number of animal and plant species. But for how much longer? Accord- ing to the Federal Office for the Environment (FOEN), under- water fauna and flora are at above-average risk compared to other organisms, with one in five species either threatened with extinction or already extinct.
Fish in particular under threat
Fish are among the most affected animal species: over 58 per- cent are on the FOEN’s red list – while nine are thought to be al- ready extinct. Ole Seehausen from EawAG, the ETH Domain’s aquatic research institute, sees three main reasons for this:
“Hydroelectric power plants prevent fish in rivers from migrat- ing,” says the fish ecologist. “In addition, nutrient oversupply in recent decades, and now global warming, have made the circu-lation of water layers in lakes more difficult – and with it the supply of oxygen to deep water. River bank stabilization, mean- while, leaves some species of fish species without a habitat at the water’s edge.”
Underwater world on a sheet
The two EUROPA stamps immerse themselves in two Swiss rivers and standing waters, which flow together symbolically to form a common habitat on the sheet of 16: one stamp shows the underwater world of Lake Thun, represented by the common Lake Thun Balchen, a species of whitefish found only in Lakes
Thun and Brienz. It is seen swimming past stoneworts and freshwater mussels hiding in the sediment. The second stamp depicts two causes for concern, species that live in the Doubs: the endangered white-clawed crayfish and the Zingel asper.
The latter is also known as the Rhone streber or Roi du Doubs, and it is the rarest fish in Switzerland. (More on this in the Focus article on pages 8–11.)
