Ecosystem services provided by the exotic bivalves

The ecosystem services approach to conservation is becoming central to environmental policy decision making. While many negative biological invasion-driven impacts on ecosystem structure and functioning have been identified, much less was done to evaluate their ecosystem services. In this paper, we focus on the often-overlooked ecosystem services provided by three notable exotic ecosystem engineering bivalves, the zebra mussel, the quagga mussel, and the golden mussel. One of the most significant benefits of invasive bivalves is water filtration, which results in water purification and changes rates of nutrient cycling, thus mitigating the effects of eutrophication. Mussels are widely used as sentinel organisms for the assessment and biomonitoring of contaminants and pathogens and are consumed by many fishes and birds. Benefits of invasive bivalves are particularly relevant in human-modified ecosystems. We summarize the multiple ecosystem services provided by invasive bivalves and recommend including the economically quantifiable services in the assessments of their economic impacts. We also highlight important ecosystem disservices by exotic bivalves, identify data limitations, and future research directions. This assessment should not be interpreted as a rejection of the fact that invasive mussels have negative impacts, but as an attempt to provide additional information for scientists, managers, and policymakers.