Invasive species and climate change are blighting Lake Constance – Vorarlberg –

This is evidenced by a major project undertaken by seven institutions from Switzerland, Germany and Austria. Researchers reported Wednesday that the current change is far-reaching and likely to have far-reaching consequences for complex ecosystem structure and water users.

Lake Constance has been closely examined for five and a half years under the direction of the Swiss water research institute Eawag in the project “Changing a Lake: Life in Lake Constance – Yesterday, Today and Tomorrow”. According to a press release from Eawag, invasive species such as the quagga mussel and stickleback have been found to cause particular problems in the lake. She added that at the beginning of the project, mussels from the Black Sea region were found sporadically. They are now colonizing the lake to great depths.

According to Eawag, sticklebacks account for up to 90 percent of the fish population in Lake Constance. In the project, the researchers showed that the success of a fish species in Lake Constance lies in its gene pool.

Spiny mussels and quaga caused a sharp collapse in the productivity of Vorarlberg’s professional fishermen. Yields have more than halved in the past ten years.

Whitefish are a big problem in Vorarlberg. In the entire Lake Constance region, the number of commercial fishermen has dropped from 120 to around 40 in the past 15 years.

However, researchers have reported positive results for blue-green algae. Increasing water temperatures due to climate change have not caused any massive epidemics of blue-green algae in Lake Constance as they have in neighboring Lake Zurich. According to the researchers, excessive fertilization of the lake can also be stopped. Thanks to appropriate measures, species adapted to conditions with lower nutritional content once again came to dominate what is now Lake Constance.

However, project manager Piet Spaak from Eawag fears that this recovery will only be short-lived: “I would assume that the Lake Constance ecosystem will change more than this in the future as a result of climate change and invasive species such as quagga mussels and sticklebacks. This has been the case over the past few decades the past.”