This project is part of the international research project SeeWandel (additional information can be found at SeeWandel and Seewandel.org).
Several invasive freshwater mussel species have invaded swiss lakes in the past. Especially the zebra and quagga mussel, Dreissena polymorpha and Dreissena bugensis, are challenging our ecosystem by affecting the food web through their high filtration rate and abundance. Due to their high filtration rate they effectively remove phytoplankton from the water column, which thus lacks other organisms as a food source. Less phytoplankton also causes clearer water, enabling light to penetrate deeper into the lake, thus promoting the growth of macrophytes. Additionally, zebra and quagga mussels can attach to various substrates including human made structures, such as anchor chains and jetties, which promotes their high abundance. The quagga mussel was first discovered in Lake Constance in 2016 and has since spread throughout the littoral zone but also colonized deeper habitats. Compared to the zebra mussel, which is found in Switzerland since the 1960’s, the quagga mussel can colonize deeper habitats and occurs in higher abundances.