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 Emilie Blevins, Laura McMullen, Sarina Jepsen, Michele Blackburn, Aimée Code, and Scott Homan Black 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 Emilie Blevins Laura McMullen Sarina Jepsen Michele Blackburn Aimée Code Scott Hoffman Black The Xerces Society for Invertebrate Conservation www.xerces.org The Xerces® Society for Invertebrate Conservation is a nonprot organization that protects wildlife through the conservation of invertebrates and their habitat. Established in 1971, the Society is at the forefront of invertebrate protection, harnessing the knowledge of scientists and the enthusiasm of citizens to implement conservation programs worldwide. The Society uses advocacy, education, and applied research to promote invertebrate conservation. The Xerces Society for Invertebrate Conservation 628 NE Broadway, Suite 200, Portland, OR 97232 Tel (855) 232-6639 Fax (503) 233-6794 www.xerces.org Regional oces from coast to coast. The Xerces Society is an equal opportunity employer and provider. Xerces® is a trademark registered in the U.S. Patent and Trademark Oce © 2018 by The Xerces Society for Invertebrate Conservation Primary Authors and Contributors The Xerces Society for Invertebrate Conservation: Emilie Blevins, Laura McMullen, Sarina Jepsen, Michele Blackburn, Aimée Code, and Scott Homan Black. Acknowledgements Funding for this report was provided by the Oregon Watershed Enhancement Board, The Nature Conservancy and Portland General Electric Salmon Habitat Fund, the Charlotte Martin Foundation, Meyer Memorial Trust, and Xerces Society members and supporters. Full list of contributors in back Editing: Matthew Shepherd, The Xerces Society Layout: Michele Blackburn, The Xerces Society Printing: Print Results, Portland, OR Citation Blevins, E., L. McMullen, S. Jepsen, M. Blackburn., A. Code, and S. H. Black. 2017. 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. 108 pp. Portland, OR: The Xerces Society for Invertebrate Conservation. (Available online at www.xerces.org). Photographs & Artwork We are grateful to the many photographers and designers for allowing us to use their wonderful photographs and artwork. The copyright for all photographs, icons, and designs is retained by the creators. None of the photographs or artwork may be reproduced without permission from the creator. For a complete list of photographers and designers, please see the Image Credits section on page 78. If you wish to contact a photographer or designer, please contact the Xerces Society at the address above. Cover Photograph A oater mussel by Roger Tabor, USFWS. Contents Acronyms and Abbreviations v Introduction 1 The Need for Freshwater Mussel Best Management Practices 1 Who the Best Management Practices Are For 3 Project Timelines 6 Site Prioritization and Conceptual Project Design 8 Mussels as Target and Indicator Species 8 Determining if Freshwater Mussels are Present 9 Project Development and Review 12 Assessing Potential Impacts 12 Determining if Salvage and Relocation is Necessary 18 Determining if You Need a Permit 22 Developing a Monitoring Plan 25 Best Management Practices for Project Design and Implementation 29 General Practices 29 Project Design and Engineering 30 Construction and Implementation 36 Vegetation Management 40 Nonindigenous Aquatic Animal Species (NAS) Management 43 Flow Management and Restoration 46 Sediment Remediation 51 Salvage and Relocation 55 Knowledge Gaps 65 Literature Cited 67 Contributors and Reviewers 77 Image Credits 78 Appendix 1. Additional Resources and Links 80 Appendix 2. Western Freshwater Mussels 82 Mussel Biology and Life History 82 Species Profiles 88 Western Pearlshell (Margaritifera falcata) 88 Western Ridged Mussel/Rocky Mountain Ridged Mussel (Gonidea angulata) 89 Floater Mussels (genus Anodonta or Sinanodonta) 90 Appendix 3. Surveying for Mussels 92 Handling and Identifying Freshwater Mussels 92 Equipment 93 Disinfecting your Equipment 94 Surveying Methods 96 Survey Area 97 Estimating Density 98 eDNA Surveys 99 Further Resources for Mussel Surveys 99 Appendix 4. Case Studies 102 Incorporating Freshwater Mussel Conservation into River Restoration 102 Implementing and Monitoring Salvage and Relocation Efforts 104 Protecting Freshwater Mussels During Sediment Remediation Projects 106 Acronyms and Abbreviations ADI Area of Direct Impact AFS American Fisheries Society APE Area of Potential Eect BLM Bureau of Land Management BMP Best Management Practice BPA Bonneville Power Administration CTUIR Confederated Tribes of the Umatilla Indian Reservation DOT Department of Transportation EPA US Environmental Protection Agency ESA Endangered Species Act IUCN International Union for Conservation of Nature MNR Monitored Natural Recovery NAS Nonindigenous Aquatic Species ODFW Oregon Department of Fish and Wildlife SCP Scientic Collection Permit UDWR Utah Department of Water Resources USFWS US Fish and Wildlife Service USGS US Geological Survey WDFW Washington Department of Fish and Wildlife Freshwater Mussel Best Management Practices v Western freshwater mussels clockwise from top left: western pearlshell mussel (Margaritifera falcata), oater mussel (genus Anodonta or Sinanodonta), and western ridged mussel (Gonidea angulata) shell valves. 1 Introduction Freshwater mussels are native, benthic, lter-feeding animals that live in permanently inundated habitat, such as perennial rivers, streams, lakes, and ponds. Mussels improve conditions for salmon, lamprey, and other native sh by enhancing water quality and supporting rich aquatic communities (Box 1; Figure 1), making them integral to the protection and restoration of native sh populations. Even though restoration of aquatic habitat specically for the benet of salmon and other sh is a conservation priority in western North America, the contributions of freshwater mussels to healthy aquatic species and ecosystems has generally been overlooked and undervalued. The Need for Freshwater Mussel Best Management Practices Unfortunately, freshwater mussels are also among the most imperiled species in North America (Lydeard et al. 2004; Haag and Williams 2014), and some of our western species of freshwater mussels are declining across their ranges (Table 1; Blevins et al. 2017). ese declines are likely a result of a number of interrelated factors, including habitat degradation and impacts to water quality and quantity, but also impacts from aquatic restoration work. Many restoration projects are focused on protection and enhancement of sh and their habitat, but freshwater mussels dier from sh in several important ways that make them vulnerable. Project designs and construction practices that do not consider these biological and ecological dierences may not adequately protect freshwater mussels. Indeed, existing populations can be directly harmed if they are not included in project planning and design, and populations may take decades to recover, if they do at all. MUSSELS ARE FOUND Mussels require permanently inundated habitat and burrowing IN FISHBEARING, substrate, making them vulnerable to changes in water levels and dewatering. PERENNIALLY WET ey are relatively sedentary; sensitive to disturbance, low oxygen, and high water temperatures; and rely on relatively stable habitat that is protected HABITAT AND MAY BE from scouring ows, exposure, and shiing substrate. Because they are also PRESENT AT YOUR SITE somewhat cryptic, they can easily be trampled, crushed, or dislodged. ey also have a complex life cycle that requires temporary attachment to sh for metamorphosis and dispersal (Box 1), so impacts to their hosts, including avoidance of habitat, can impact mussel reproduction. Freshwater Mussel Best Management Practices 1 Box 1. Benets of Freshwater Mussels and Their Unique Life History Freshwater mussels provide important benets to native sh, aquatic ecosystems, and human communities. For example: Pacic lamprey larvae can grow faster when found near western pearlshell mussel beds, which capture, concentrate, and deposit food near their burrows (Limm and Power 2011). Western pearlshell mussels increase populations of other macroinvertebrates, which are an important food source for salmonids and other native sh (Howard and Cuey 2006b). Floater mussels lter water and can remove pharmaceuticals and E. coli (Ismail et al. 2014, 2015). Other species, such as river otters, rely on freshwater mussels for sustenance, especially when other prey is scarce (Scordino et al. 2016). Research has even shown that freshwater mussels can reduce bacterial populations, resulting in lower sh mortality and increased growth (Othman et al. 2015). These and other benets are also discussed in detail by Vaughn (2017) and Strayer (2017). Western Freshwater Mussel Life History There are multiple species of freshwater mussels that inhabit sh-bearing streams, rivers, lakes, and ponds in western North America, from Alaska to Mexico and as far inland as Montana (see Table 1 for a list). Adult mussels burrow into sediment or sit between rocks, and are often not an obvious presence,