U.S. Fish and Wildlife Service Scaleshell Mussel Recovery Plan (Leptodea leptodon) February 2010 Department of the Interior United States Fish and Wildlife Service Great Lakes – Big Rivers Region (Region 3) Fort Snelling, MN Cover photo: Female scaleshell mussel (Leptodea leptodon), taken by Dr. M.C. Barnhart, Missouri State University Disclaimer This is the final scaleshell mussel (Leptodea leptodon) recovery plan. Recovery plans delineate reasonable actions believed required to recover and/or protect listed species. Plans are published by the U.S. Fish and Wildlife Service and sometimes prepared with the assistance of recovery teams, contractors, state agencies, and others. Objectives will be attained and any necessary funds made available subject to budgetary and other constraints affecting the parties involved, as well as the need to address other priorities. Recovery plans do not necessarily represent the views or the official positions or approval of any individuals or agencies involved in plan formulation, other than the U.S. Fish and Wildlife Service. They represent the official position of the U.S. Fish and Wildlife Service only after being signed by the Regional Director. Approved recovery plans are subject to modifications as dictated by new findings, changes in species status, and the completion of recovery actions. The plan will be revised as necessary, when more information on the species, its life history ecology, and management requirements are obtained. Literature citation: U.S. Fish and Wildlife Service. 2010. Scaleshell Mussel Recovery Plan (Leptodea leptodon). U.S. Fish and Wildlife Service, Fort Snelling, Minnesota. 118 pp. Recovery plans can be downloaded from the FWS website: http://endangered.fws.gov i ACKNOWLEDGMENTS Many individuals and organizations have contributed to our knowledge of the scaleshell mussel and work cooperatively to recover the species. The U.S. Fish and Wildlife Service gratefully acknowledge the commitment, efforts, and valuable input of the following individuals in the preparation of this recovery plan. Richard Baker ----- Minnesota Department of Natural Resources, Section of Wildlife, St. Paul, MN Dr. Chris Barnhart ----- Missouri State University, Department of Biology, Springfield, MO Sue Bruenderman ----- Kentucky Division of Water, Water Quality Branch, Frankfort, KY Alan Buchanan ----- Missouri Department of Conservation, Columbia, MO Chris Davidson ----- U.S. Fish and Wildlife Service, Ecological Services, Conway, AR Heidi Dunn ----- Ecological Specialists, Inc., O’Fallon MO Scott Faiman -----Missouri Department of Conservation, Resource Science Division, Columbia, MO Craig Fuller ----- Missouri Department of Conservation, Lebanon, MO Dr. John Harris ----- Arkansas Highway Department, Environmental Division, Little Rock, AR Jessica Hogrefe ----- U.S. Fish and Wildlife Service, Regional Office, Region 3, Fort Snelling, MN Peggy Horner ----- Missouri Department of Conservation, Jefferson City, MO Alan Leary ----- Missouri Department of Transportation, Jefferson City, MO Steven McMurray ----- Missouri Department of Conservation, Resource Science Division, Columbia, MO David Martinez ----- U.S. Fish & Wildlife Service, Ecological Services, Tulsa, OK Dr. Paul McKenzie ----- U.S. Fish and Wildlife Service, Ecological Services, Columbia, MO T.J. Miller ----- U.S. Fish and Wildlife Service, Regional Office, Region 3, Fort Snelling, MN Dr. Richard Neves ----- Virginia Polytechnic Institute and State University, Department of Fisheries and Wildlife Sciences, Blacksburg, VA Carlita Payne ----- U.S. Fish and Wildlife Service, Regional Office, Region 3, Fort Snelling, MN Bill Posey ----- Arkansas Game and Fish Commission, Perrytown, AR Rob Pulliam ----- Missouri Department of Conservation, Fisheries Division, Sullivan, MO Susan Oetker ----- U.S. Fish and Wildlife Service, Ecological Services, Bloomington, MN Charles M. Scott ----- U.S. Fish and Wildlife Service, Ecological Services, Columbia, MO Mellisa Shiver ----- Missouri Department of Transportation, Jefferson City, MO Leslie Tewinkel ----- U.S. Fish and Wildlife Service, Regional Office, Region 3, Fort Snelling, MN1 Dr. Caryn Vaughn ----- The University of Oklahoma, Oklahoma Biological Survey, Norman, OK Chris Vitello ----- Missouri Department of Conservation, Springfield Conservation Office, Springfield, MO 1 Formerly with USFWS. ii EXECUTIVE SUMMARY Current Species Status: The scaleshell mussel (Leptodea leptodon) is a federally listed, endangered species that once occurred in 56 rivers in the Mississippi River Drainage. The species has undergone a dramatic reduction in range and is believed to be extirpated from 9 of the 13 states it historically occurred in. While the species has been documented from 18 streams in the last 25 years, it can only be found consistently in three streams in Missouri where it is still very rare. Habitat Requirements and Limiting Factors: The scaleshell occurs in medium to large rivers with low to medium gradients. It primarily inhabits stable riffles and runs with gravel or mud substrate and moderate current velocity. The scaleshell requires good water quality, and is usually found where a diversity of other mussel species are concentrated. More specific habitat requirements of the scaleshell are unknown, particularly of the juvenile stage. Water quality degradation, sedimentation, channel destabilization, and habitat destruction are contributing to the decline of the scaleshell throughout its range. The spread of the non-native zebra mussel (Dreissena polymorpha) may threaten scaleshell populations in the near future. The scaleshell must complete a parasitic phase on freshwater drum (Aplodinotus grunniens) to complete its life cycle. The scaleshell’s complex life cycle and extreme rarity hinders its ability to reproduce. The sedentary nature of the species and the low density of remaining populations exacerbate threats to its survival posed by the natural and manmade factors. Further, the relatively short life span of the scaleshell may render it less able to tolerate periods of poor recruitment. The remaining populations are very susceptible to local extirpation, with little chance of recolonization because of their scattered and isolated distribution. Recovery Strategy: Scope of threats and recovery: Streams occupied by the scaleshell have numerous and widespread threats affecting the species. In some cases, these threats are related to the surrounding land use and can originate far upstream of extant populations. Therefore, threats not only need to be addressed immediately adjacent to occupied sites, but also in the watershed upstream. Some recovery actions may need to be implemented on a large scale in order to restore aquatic habitat downstream. Recovery efforts on this scale will not be possible without soliciting outside help to restore aquatic habitat and improve surface lands. The assistance of federal and state agencies, conservation groups, local governments, private landowners, industries, businesses, and farming communities will be essential in implementing the necessary recovery actions for the scaleshell to meet recovery goals. The role of private landowners, non- profit organizations, and corporations cannot be over emphasized as most land in watersheds occupied by the scaleshell is under private ownership. Addressing threats: To solicit outside help and foster the many partnerships needed to address threats, a recovery implementation team will be formed. This team may be made up of species experts and representatives from federal and state wildlife agencies, other federal and state agencies, non-government organizations, academia, and other concerned groups with a diversity iii of expertise on conservation science and public relations within the scaleshell’s range. This team will take a strategic approach to address threats and work with willing partners to carry out the appropriate recovery actions to protect existing habitat, alleviate threats, and restore habitat. First, threats will be identified, assessed, and mapped for each watershed occupied by the scaleshell. Then a strategic recovery implementation database will be developed to guide recovery efforts for each population. The database will be used to prioritize populations, threats, and needed recovery actions as well as track recovery efforts and document when threats to each population have been alleviated. The threat mapping and strategic database are an integral part of the recovery strategy for the scaleshell. Watershed improvements will be aimed at addressing the various causes of habitat degradation including sedimentation; point and non-point pollution sources; substrate destabilization; land, bank, and channel erosion; and eutrophication. Examples of watershed improvements to alleviate these threats include, but are not limited to the following: improving wastewater treatment plants, reestablishing protective riparian corridors to reduce sedimentation; stabilizing stream banks; reducing sheet run-off; using no-till agricultural methods; controlling nutrient enrichment by carefully planning heavy livestock use areas; excluding cattle from streams by erecting fences and providing alternative water supplies; development of gravel mining guidelines; and implementing voluntary best management practices to control run-off for a variety of agricultural, silvicultural, and construction activities. Other factors that potentially will affect the scaleshell in the future include the introduction of non-native species,