Best Management Practices for Freshwater Mussels at Restoration and Construction Sites

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1 Best Management Practices for Freshwater Mussels at Restoration and Construction Sites Emilie Blevins Xerces Society for Invertebrate Conservation Image credit: Roger Tabor, USFWS.

2 Xerces Society for Invertebrate Conservation is an international nonprofit organization that protects wildlife through the conservation of invertebrates and their habitats. Since 1971, we have worked on habitat conservation and restoration, species conservation, protecting pollinators, contributing to watershed health, and reducing harm to invertebrates from pesticide use. Image credit: Dana Ross.

3 Freshwater Mussels Native to the US Benthic-dwelling, filtering bivalve Complex life cycle May form beds of 100s or 1,000s Can be long lived ( years) Highly imperiled Image credit: Associated Press; Xerces Society.

4 Fish & aquatic life (& people!) benefit Image credit: Xerces Society; USFWS.

5 Western Species Near Threatened Vulnerable* Vulnerable Vary in age and host fish Overlap in habitat with some differences All can vary in density Each species distributed throughout Oregon Image credit: Xerces Society; CTUIR; Roger Tabor, USFWS.

6 Mussels in the Willamette Basin mussels reported from >80 waterbodies in the Willamette Basin (and many beyond) one or more species likely present in additional unsurveyed reaches crowd-sourced data invaluable please share! database can be queried to assist with your work Image credit: Xerces Society.

7 Why do we need BMPs? Freshwater mussels are declining for known and unknown reasons. inhabit fish-bearing rivers, creeks, lakes, and ponds. thrive in stable and stabilized reaches and require permanent inundation. are relatively immobile and present year-round. are easily overlooked, trampled, crushed, and dislodged. are sensitive to disturbance and habitat alteration. are protected under state permitting requirements. = protect existing values and maximize restoration benefits Image credit: Xerces Society; The Nature Conservancy.

8 Determining Presence Conduct a survey in-water Determine early (>1 year in advance) Preliminary surveys/no project footprint vs. project planning/known footprint Image credit: Xerces Society.

9 Planning, Design, and Engineering BMPs Recommendation: Avoid projects that directly impact large populations of mussels. Approach: If possible, change the location of the project or elements of the project. Recommendation: Salvage and relocate mussels when location cannot change (i.e., culvert replacement, toxic sediment). Approach: Develop a salvage and relocation plan and implement BMPs in advance of construction/project activities. Recommendation: Reduce indirect impacts to mussels. Approach: Assess indirect impacts by modeling changes in flow or scour, potential for sediment transport, or reduction of inundated habitat. Recommendation: Create or enhance habitat for mussels at sites. Approach: Protect or provide burrowing sediment free of toxic materials stable habitat with low shear stress inundated habitat with flow sufficient to carry food and oxygen habitat safe from predators temperatures that support growth and reproduction Image credit: Xerces Society.

10 Assessing the Project Does your project occur in an area with a large number of mussels? Will you dewater an area where mussels occur? Will the project alter shores, banks or beds of aquatic habitat? new channel construction or meandering removal or placement of hard structures (rock barbs, log jams, retaining walls, piers) removal of vegetation Will areas of the site require active and continued maintenance? regulation of water levels phased projects Does the site require special activities (cleanup of contaminated sediment or dredging)? Will the site increase recreation near mussels? Image credit: Xerces Society.

11 General BMPs Time work to protect mussels: mussels present year-round avoid or limit bigger impacts (salvage and relocation, activities that result in fish avoidance) during sensitive periods avoid impacts during warmer temperatures Establish an area of avoidance: limit frequent activity at the mussel bed to reduce the potential for trampling or crushing clearly designate or mark the area or otherwise deter use within ~5m Maintain protective, complex habitat microrefugia: crevices, roots, depressions, boulders Image credit: Roger Tabor, USFWS; Xerces Society.

12 Salvage and Relocation BMPs Coordinate early and plan for salvage a year in advance. Develop a mussel salvage plan. Know who, when, where to and from, and how. Plan more than one visit. Return to the site after the first salvage and collect remaining mussels. During dewatering or fish salvages, continue to collect mussels as they are found. Plan to monitor the success of your relocation effort. Share your information! Image credit: Xerces Society.

13 Vegetation Management BMPs (examples) Among tested aquatic animals, mussels are often the most sensitive to chemicals juveniles and glochidia are especially at-risk can be as much as 20x more sensitive than fish to certain chemicals tests for effects on mussels have been limited Recommend avoiding use of herbicides near freshwater mussels mussels are exposed to many chemicals simultaneously mussel beds often located near banks effects range from lethal to sublethal If herbicides are used, establish a large buffer review studies at pesticideimpacts.org monitor for signs of mortality or distress Image credit: Alexa Maine, CTUIR.

14 Are mussels in distress? Mussels can clam up to avoid some impacts but they can also be seen: gaping or showing a delayed reaction to handling avoiding an area by crawling away Die-off signs: delayed and/or weakened valve (shell) closing when touched or removed from the substrate lying flat on the substrate or floating in the water valves gaping wide open an extremely foul odor not a shell midden, with evidence of predation, like tooth marks or broken valves Image credit: Xerces Society.

15 Other BMPs and Resources Aquatic invasive species treatments (rotenone, zebra mussel control) Flow restoration (dam removal, reservoir drawdown, dam operations) Sediment remediation (dredging, capping, chemical application) + more as issues raised and research advances questions, experience, and input from the restoration community opportunities to field test and incorporate observations Xerces is looking to partner and assist adding to regional resources

16 Next Steps Complete technical review and incorporate feedback (Now) Publish and distribute (Winter 2017/Spring 2018) Develop user-friendly guide (Winter 2017/Spring 2018) Provide additional workshops (Fall 2017 Summer 2018) Provide technical assistance (ongoing please get in touch!) Continue to refine and improve BMPs Image credit: Patrick Norton, Patrick Norton Illustrations.

17 Acknowledgements Thank you to coauthors, technical contributors, and reviewers (full list in BMP document)! Thank you to our funders and supporters: OWEB, Charlotte Martin Foundation, Meyer Memorial Trust, PGE and The Nature Conservancy, Confederated Tribes of the Umatilla Indian Reservation, PNW Mussel Workgroup, and Xerces Society members /pnwmussel Image credit: Xerces Society.