The invasive Quagga mussel (Dreissena rostriformis bugensis) has established populations in several Swiss lakes and rivers over the past decade. This species shows remarkable ecological plasticity, being able to reproduce almost all year round and colonizing the hard and soft substrates across a wide depth gradient, from shallow water to depths of over 300 m. Across depths, two distinct ecotypes occur, the shallow ecotype (typical) and the deep ecotype (profunda), which is found from 20-30m depth in Lake Constance. While morphological differences between shallow- and deep-water populations have been observed, no genetic differentiation was found across the whole genome, indicating that the development of the profunda morph is the result of phenotypic plasticity. However, it is not known if the profunda morph provides an adaptive advantage for living at greater depths or if it is the result of other environmental factors.

Climate change is expected to alter key environmental factors such as temperature, oxygen levels and food availability in Swiss lakes. Therefore, understanding how Quagga mussels will respond and adapt to these changes is critical to predicting their future impact and population dynamics.

By combining field observations, experimental results and environmental data, this project will provide a better understanding of the adaptive ability of the invasive Quagga mussel in a changing environment, with important applications for the development of effective management strategies for Swiss freshwater ecosystems.