Researchers of the ELKH Balaton Limnological Research Institute (BLKI) examined the ecosystem impacts and recovery under individual and serial invasions of dreisenid mussels in European and North American shallow lakes within an international collaboration. They found that the ecosystem impacts of invasive species can subside over time but amplify with serial introductions of competing, even closely similar, taxa. The paper detailing these findings was published in Ecosystems.
The researchers monitored the invasion dynamics of dreissenid species (Dreissena polymorpha ‒ the zebra mussel, and Dreissena rostriformis bugensis ‒ the quagga mussel) in seven different shallow lakes of Europe and North America, including Lake Balaton. They compared changes in seven key ecosystem features, such as the presence and mass of the two mussel species and their food (the phytoplankton), as well as water transparency before and after the invasions. Based on long-term data analysis, the study found that the strongest ecosystem impact occurs within 5-10 years of zebra mussel invasion, with a partial ecosystem (e.g. plankton community) recovery thereafter. However, recovery failed, impacts of initial invasion amplified, with a stronger decline in phytoplankton abundance in lakes where quagga mussels followed zebra mussel invasion. The research concluded that the impacts of species invasion subside over time, but if multiple invasions occur consecutively, the opposite can be expected. Results provide valuable insights into the post-invasion dynamics and recovery of ecosystems, based on which recommendations can be addressed for restoring desired ecological states.
Dreissenid mussel colonies in the rocky shoreline of Lake Balaton (scale bar: 10 cm).