Though less well-known than other aquatic species, freshwater mussels are an important component of our natural and cultural heritage in North America and the West. These species improve water quality and habitat for imperiled salmon and other native fish, other aquatic species, and people. However, western freshwater mussels are declining in distribution and abundance across their historic ranges and face many threats, including habitat degradation and impacts to water quality and quantity.
Perhaps somewhat surprisingly, restoration projects and activities are also counted among those threats. Although mussels can benefit from improvements to habitat, their vulnerability to dewatering, construction activities, and changes to riverbed and bank habitat—and their inconspicuous appearance—leave them at risk from these projects. Indeed, mussel beds (the term for the tens, hundreds, or thousands of mussels found in aggregations) are often killed during restoration projects aimed at improving habitat for salmon.
The decline of western freshwater mussels is important to river conservation and relevant to river restoration practitioners because mussels provide numerous ecosystem services that already support fragile aquatic communities. Because mussel populations can take years to recover from impacts, potentially a decade or more for some species, avoiding impacts to mussels is critical to preserving existing habitat values and conserving declining freshwater species.
Fortunately, freshwater mussel conservation can be incorporated into projects, a practice now becoming more common in western states and provinces. To assist practitioners and improve efforts, the Xerces Society has published Conserving the Gems of Our Waters: Best Management Practices for Protecting Native Western Freshwater Mussels During Aquatic and Riparian Restoration, Construction, and Land Management Projects and Activities. This publication draws from the expertise of members of the Pacific Northwest Native Freshwater Mussel Workgroup, western restoration practitioners, and aquatic biologists, and provides guidance and resources for a range of topics, from incorporating freshwater mussels into project planning, surveying for mussels, implementing best management practices, and performing salvages and relocations at restoration sites.
Contact [email protected] to obtain a printed version.