FRESHWATER MOLLUSK BIOLOGY AND CONSERVATION THE JOURNAL OF THE FRESHWATER MOLLUSK CONSERVATION SOCIETY VOLUME 19 NUMBER 2 SEPTEMBER 2016 Pages 1-18 Jesse T. Holifield, Thomas A. Tarpley, and Paul D. Quantitative Monitoring of Freshwater Mussel Popula- Johnson tions from 1979–2004 in the Clinch and Powell Rivers Pages 56-68 of Tennessee and Virginia, with Miscellaneous Notes on Genetic Structure of Faucet Snail, Bithynia tentaculata the Fauna Populations in North America, Based on Microsatellite Steven A. Ahlstedt, Mark T. Fagg, Robert S. Butler, Markers Joseph F. Connell, and Jess W. Jones Kathryn E. Perez, Rebecca L. Werren, Christopher Pages 19-26 A. Lynum, Levi A. Hartman, Gabor Majoros, and Growth and Longevity Estimates for Mussel Populations Rebecca A. Cole in Three Ouachita Mountain Rivers Pages 69-79 Brandon J. Sansom, Carla L. Atkinson, and Caryn C. Life Stage Sensitivity of a Freshwater Snail to Herbi- Vaughn cides Used in Invasive Aquatic Weed Control Pages 27-50 Jennifer M. Archambault and W. Gregory Cope Microhabitat Suitability and Niche Breadth of Common and Pages 80-87 Imperiled Atlantic Slope Freshwater Mussels Assessment of a Short-Distance Freshwater Mussel Tamara J. Pandolfo, Thomas J. Kwak, and W. Relocation as a Viable Tool During Gregory Cope Bridge Construction Projects Pages 51-55 Jeremy S. Tiemann, Michael J. Dreslik, Sarah J. Use of Side-Scan Sonar to Locate Tulotoma magnifica Baker, and Christopher A. Phillips (Conrad, 1834) (Gastropoda: Viviparidae) in the Ala- bama River Jeffrey T. Garner, Michael L. Buntin, Todd B. Fobian, Freshwater Mollusk Biology and Conservation ©2016 ISSN 2472-2944 Editorial Board CO-EDITORS Gregory Cope, North Carolina State University Wendell Haag, U.S. Department of Agriculture Forest Service Tom Watters, The Ohio State University EDITORIAL REVIEW BOARD Conservation Jess Jones, U.S. Fish & Wildlife Service / Virginia Tech University Ecology Ryan Evans, Kentucky Department of Environmental Protection, Division of Water Michael Gangloff, Appalachian State University Caryn Vaughn, Oklahoma Biological Survey, University of Oklahoma Freshwater Gastropods Paul Johnson, Alabama Aquatic Biodiversity Center Jeff Powell, U.S. Fish & Wildlife Service, Daphne, Alabama Jeremy Tiemann, Illinois Natural History Survey Reproductive Biology Jeff Garner, Alabama Division of Wildlife and Freshwater Fisheries Mark Hove, Macalester College / University of Minnesota Survey/Methods Heidi Dunn, Ecological Specialists, Inc. Patricia Morrison, U.S. Fish & Wildlife Service Ohio River Islands Refuge David Strayer, Cary Institute of Ecosystem Studies Greg Zimmerman, Enviroscience, Inc. Systematics/Phylogenetics Arthur Bogan, North Carolina State Museum of Natural Sciences Daniel Graf, University of Wisconsin-Stevens Point Randy Hoeh, Kent State University Toxicology Thomas Augspurger, U.S. Fish & Wildlife Service, Raleigh, North Carolina Robert Bringolf, University of Georgia John Van Hassel, American Electric Power Teresa Newton, USGS, Upper Midwest Environmental Sciences Center Freshwater Mollusk Biology and Conservation 19:1–18, 2016 Ó Freshwater Mollusk Conservation Society 2016 REGULAR ARTICLE QUANTITATIVE MONITORING OF FRESHWATER MUSSEL POPULATIONS FROM 1979–2004 IN THE CLINCH AND POWELL RIVERS OF TENNESSEE AND VIRGINIA, WITH MISCELLANEOUS NOTES ON THE FAUNA Steven A. Ahlstedt1, Mark T. Fagg2, Robert S. Butler3, Joseph F. Connell4, and Jess W. Jones5* 1 P.O. Box 460, Norris, TN 37828 USA 2 551 Ravenswood Drive, Morristown, TN 37814 USA 3 U.S. Fish and Wildlife Service, 160 Zillicoa Street, Asheville, NC 28801 USA 4 108 Orchard Circle, Oak Ridge, TN 37830 USA 5 U.S. Fish and Wildlife Service, Department of Fish and Wildlife Conservation, 106a Cheatham Hall, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 USA ABSTRACT The Clinch and Powell rivers, Tennessee (TN) and Virginia (VA), upstream of Norris Reservoir, TN, are known for high freshwater mussel species diversity and endemism. Collectively, these rivers harbored at least 56 species historically and 49 are extant, many of which now survive only in the Clinch or Powell rivers or a few other streams. Among an unparalleled 24 federally endangered mussel species known from these rivers, 20 species are considered extant. We sampled 0.25 mÀ2 quadrats at six Clinch River sites and four Powell River sites for a total of 4–6 sample years at each site. Overall trends were highly significant in the Clinch River, with mean mussel density at combined sites in each state increasing from 16.5 mÀ2 to 41.7 mÀ2 (p , 0.0001) at sites in TN but declining from 12.0 mÀ2 to 3.3 mÀ2 (p , 0.001) at sites in VA. Cumulative species richness was 39, ranging from 36 in TN to 27 in VA. Greater density in the Clinch River, TN, was due primarily to increases in Epioblasma capsaeformis, Medionidus conradicus,andPtychobranchus subtentus, which were rare or undetected at most sites in 1979, but increased five- to ten-fold by 2004. Conversely, at Pendleton Island, VA, which was the best site for mussels in the river circa 1980, the decline in density was highly significant, from 24.6 mÀ2 in 1979 to 4.6 mÀ2 (p , 0.001) in 2004. In the Powell River, there was also a highly significant decline in mean mussel density at combined sites from 8.7 mÀ2 to 3.3 mÀ2 (p , 0.001), with a total of 33 species documented. Though species diversity remains relatively high, our results confirm that mussel populations have declined in large reaches of each river over the 25-year study period. KEY WORDS - Clinch and Powell rivers; biodiversity hotspot; freshwater mussels; endangered species; mussel population declines. INTRODUCTION of any comparably-sized river system in the world. More than The Clinch River and its largest tributary Powell River are 105 species are known from this drainage, with at least 36 species endemic to it or shared only with the Cumberland River located in northeastern TN and southwestern VA and are part of drainage (Parmalee and Bogan 1998). Collectively, upland the upper Tennessee River drainage (Figure 1). The Tennessee portions of these two drainages are known as the Tennessee- River drainage supports the highest freshwater mussel diversity Cumberland Province (Haag 2010). Mussel diversity was highest in the mainstem Tennessee River and its large *Corresponding author: [email protected] tributaries, but impoundments created during the 1920s through 1 2 AHLSTEDT ET AL. Figure 1. The Clinch and Powell river watersheds showing locations of sites (in RKM) sampled from 1979–2004. 1970s destroyed most large-river habitats (Haag 2009). The stegaria, E. florentina aureola, Lemiox rimosus, Pegias lower Clinch River was impounded by Watts Bar Dam on the fabula, Pleurobema plenum, Q. sparsa, Venustaconcha Tennessee River, and Melton Hill and Norris dams on the trabalis [studies by Kuehnl (2009) and Lane et al. (2016) Clinch River (river km [RKM] 37.0 and 128.5, respectively). have shown that Villosa trabalis belongs in the genus Norris Dam impounds the river to about river km 249 as well as Venustaconcha,andthatVillosa perpurpurea is a synonym; the lower 90 km of the Powell River, and the dam effectively see Discussion]), of 15 endangered mussels, in addition to isolated these two rivers and eradicated at least 10 additional large populations of several other imperiled species (Jones et species from the drainage (Ortmann 1918; Ahlstedt 1991a). al. 2014; Table 1). Fifteen of 19 endangered species are Nevertheless, the free-flowing upper reaches of the Clinch and considered extant in the Powell River, which itself harbors 1 Powell rivers are among the most important remaining riverine of only 2 extant populations of D. dromas, Q. cylindrica habitats in the Tennessee River drainage, and they support a strigillata, Q. intermedia,andQ. sparsa (Johnson et al. large percentage of the surviving mussel fauna of the region 2012). (Johnson et al. 2012; Jones et al. 2014). Various malacologists have reported on the mussels in the Among the 56 species known historically from the Clinch and Powell rivers over the last century. Arnold E. Clinch and Powell river mainstems upstream of Norris Ortmann (1918), Carnegie Museum, Pittsburgh, Pennsylvania, Reservoir, 24 are now federally endangered under the reported the only systematic pre-impoundment collection Endangered Species Act (ESA), though 4 of these listed records in the study area, including several records from species are considered extinct or extirpated from these rivers Adams (1915). In the 1960s and 1970s, David H. Stansbery, (Table 1). Further, an additional seven of the extant species Ohio State University Museum of Biological Diversity, are included in a petition for possible federal listing. The Columbus, Ohio, and his students made scores of collections Clinch River harbors the largest remaining population in the study area, documenting declines in species richness (namely, Dromus dromas, Epioblasma brevidens, E. cap- since Ortmann’s (1918) collections, many from areas now saeformis, Fusconaia cor, F. cuneolus, Hemistena lata, inundated by Norris Reservoir (Stansbery 1973). Greater Ptychobranchus subtentus, Quadrula cylindrica strigillata), survey effort and interest in conserving the mussel fauna or one of the few existing populations (e.g., Cyprogenia accelerated in the mid-1970s following passage of the ESA in FRESHWATER MUSSELS OF THE CLINCH AND POWELL RIVERS 3 Table 1. Scientific names, and federal and Freshwater Mollusk Conservation Society (FMCS; J.D. Williams, Florida Museum of Natural History, unpub.