Species Status Assessment Report for the Purple Lilliput (Toxolasma lividum) Photo credit: The Mussel Project February 2020 Version 1.0 U.S. Fish and Wildlife Service South Atlantic-Gulf Atlanta, GA Primary Contributors • Andrew Henderson - Asheville Field Office, Lead Biologist (Legacy Region 4) • Heidi Crowell - Pacific Southwest Regional Office, SAT Project Manager (Legacy Region 8) • Gary Peeples - Asheville Field Office (Legacy Region 4) • Josh Hundley - Missouri Field Office (Legacy Region 3) • David Martinez - Oklahoma Field Office (Legacy Region 2) Peer Reviewer • Dr. Wendell Haag (U.S. Forest Service) Contributors & Partner Agency Reviewers (underlined) • Rose Agbalog, Angela Boyer, Bob Butler (retired), Stephanie Chance, Chris Davidson, Andy Ford, Leroy Koch (retired) (U.S. Fish & Wildlife Service) • Chuck Howard, Tim Keeling (Tennessee Valley Authority) • Kendall Moles (Arkansas Game and Fish Commission) • Peter Badra, Rebecca Rogers (Michigan Natural Features Inventory) • Stephanie Williams (Tennessee Department of Environment and Conservation) • Jeff Grabarkiewicz (Michigan Department of Transportation) • Dr. Arthur Bogan, Jamie Smith (North Carolina Museum of Natural Sciences) • Jeremy Tiemann, Rachel Vinsel, Kevin Cummings (Illinois Natural History Survey) • Heidi Dunn, Emily Grossman (Ecological Specialists, Inc.) • Brian Watson, Karen Horodysky (Virginia Department of Game and Inland Fisheries) • Dr. Paul Johnson, Jeff Garner, Michael Buntin, Todd Fobian, Ashley Peters (Alabama Department of Conservation and Natural Resources) • Gerry Dinkins (University of Tennessee McClung Museum) • Greg Zimmermann (EnviroScience, Inc.) • Steve McMurray (Missouri Department of Conservation) • Mike Compton, Ian Horn (Kentucky State Nature Preserves Commission) • Chad Lewis, Clarissa Lawliss (Lewis Environmental Consulting) • Debbie Wolschki (Ohio Natural Heritage Program) • Brant Fisher (Indiana Department of Natural Resources) • Dr. Monte McGregor, Keith Wethington (Kentucky Department of Fish and Wildlife Resources) • Stuart McGregor (Geological Survey of Alabama) • Don Hubbs (Tennessee Wildlife Resources Agency) iii SUGGESTED CITATION: U.S. Fish and Wildlife Service (Service). 2020. Species Status Assessment Report for the Purple Lilliput Mussel (Toxolasma lividum), Version 1.0. Asheville Ecological Services Field Office, Asheville, North Carolina. iv TABLE OF CONTENTS ACRONYMS .............................................................................................................................. viii EXECUTIVE SUMMARY .......................................................................................................... ix CHAPTER 1 - INTRODUCTION ............................................................................................. 13 1.1 Purpose of SSA .................................................................................................................. 13 1.2 Species Basics - Taxonomy and Evolution ...................................................................... 13 1.2.1 Taxonomy ................................................................................................................... 15 1.3 Petition History ................................................................................................................. 15 1.4 State Listing Status ........................................................................................................... 16 CHAPTER 2 - METHODOLOGY AND DATA...................................................................... 17 2.1 SSA Framework ................................................................................................................ 17 2.1.1 Species Needs .............................................................................................................. 17 2.1.2 Current Species Condition ........................................................................................ 18 2.1.3 Future Species Condition .......................................................................................... 20 CHAPTER 3 - SPECIES BACKGROUND AND ECOLOGY............................................... 21 3.1 Physical Description.......................................................................................................... 21 3.2 Genetics .............................................................................................................................. 22 3.3 Life History ........................................................................................................................ 22 3.4 Reproduction ..................................................................................................................... 23 CHAPTER 4 - RESOURCE NEEDS ........................................................................................ 25 4.1 Individual-level Resource Needs ...................................................................................... 25 4.1.1 Suitable Aquatic Habitats ......................................................................................... 26 4.1.2 Appropriate Water Quality and Temperatures ...................................................... 27 4.1.3 Food and Nutrients .................................................................................................... 28 4.2 Population- and Species-level Needs ............................................................................... 28 4.2.1 Connectivity of Aquatic Habitat ............................................................................... 28 4.2.2 Dispersal-Adult Abundance and Distribution......................................................... 28 4.2.3 Host Fish ..................................................................................................................... 29 4.3 Uncertainties ...................................................................................................................... 29 v 4.4 Summary of Resource Needs ........................................................................................... 30 CHAPTER 5 - CURRENT CONDITIONS, ABUNDANCE AND DISTRIBUTION .......... 31 5.1 Historical Conditions For Context .................................................................................. 32 5.2 Current Population Abundance, Trends, and Distribution .......................................... 33 5.3 Estimated Viability of Purple Lilliput Mussel Based on Current Conditions ............ 36 5.3.1 Resiliency .................................................................................................................... 36 5.3.2 Representation............................................................................................................ 45 5.3.3 Redundancy ................................................................................................................ 45 5.4 Uncertainties of Current Condition ................................................................................ 46 CHAPTER 6 - FACTORS INFLUENCING VIABILITY ...................................................... 46 6.1 Habitat Degradation or Loss ........................................................................................... 48 6.1.1 Agricultural Activities ............................................................................................... 48 6.1.2 Development/Urbanization ....................................................................................... 50 6.1.3 Contaminants ............................................................................................................. 54 6.1.4 Dams and Barriers ..................................................................................................... 58 6.1.5 Resource Extraction................................................................................................... 59 6.1.6 Changing Climate Conditions ................................................................................... 62 6.1.7 Forest Conversion ...................................................................................................... 63 6.2 Invasive and Nonnative Species ....................................................................................... 65 6.3 Genetic Isolation................................................................................................................ 68 6.4 Enigmatic Population Declines ........................................................................................ 69 6.5 Factors Currently Believed To Have Limited Effects on Purple Lilliput Populations .............................................................................................................................. 69 6.5.1 Parasites ...................................................................................................................... 69 6.5.2 Predation ..................................................................................................................... 69 6.6 Overall Summary of Factors Affecting the Species ....................................................... 70 CHAPTER 7 - FUTURE CONDITIONS ................................................................................. 71 7.1 Future Scenario Considerations ...................................................................................... 71 7.2 Future Scenarios ............................................................................................................... 71 7.3 Scenario 1 ..........................................................................................................................