Status of Native and Exotic Mussels
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Status of Native and Exotic Mussels, Including the Northern Riffleshell (Epioblasma torulosa rangiana) and Rayed Bean (Villosa fabalis), at the Detroit River International Wildlife Refuge: Sites 15-36 Prepared by: Peter J. Badra Michigan Natural Features Inventory P.O. Box 30444 Lansing, MI 48909-7944 For: U.S. Fish and Wildlife Service, Challenge Cost Share Fund December 23, 2006 MNFI Report Number 2006-23 Background photo: Site 34 in the Fermi/Swan Creek area. Photo by John Matousek. Left inset photo: Ready to start SCUBA transect search at Mamajuda Island Shoal. Photo by Peter Badra. Right inset photo: Unionid mussels found at Site 35 in the Fermi/Swan Creek area. Fragile papershell (Leptodea fragilis) center, mapleleaf (Quadrula quadrula) around edge. Photo by John Matousek. Citation: Badra, P. J. 2006. Status of native and exotic mussels, including the northern riffleshell (Epioblasma torulosa rangiana) and rayed bean (Villosa fabalis), at the Detroit River International Wildlife Refuge: Sites 15-36. Report number MNFI 2006-23. Report to U.S. Fish and Wildlife Service, Ft. Snelling, MN. 15pp. Copyright 2006 MSU Board of Trustees Table of Contents Abstract ........................................................................................................................................................... 1 Introduction .................................................................................................................................................... 1 Methods ........................................................................................................................................................... 2 Results .............................................................................................................................................................. 3 Discussion ........................................................................................................................................................ 4 Acknowledgments ......................................................................................................................................... 14 Literature Cited ............................................................................................................................................ 14 List of Figures Figure 1. Survey sites 15-21 and 25-28, at Mud Island, Grassy Island, and Mamajuda Island Shoal, Detroit River............................................................................................................................................................ 4 Figure 2. Survey sites 22-24 at the Berenholz tract, Lake Erie. ...................................................................... 5 Figure 3. Survey sites 29-33 at Sugar Island and Calf Island, Detroit River................................................... 6 Figure 4. Survey sites 34-36 at the Fermi/Swan Creek area. .......................................................................... 7 Figure 5. Unionid mussels from site 35 in the Fermi/Swan Creek area. ......................................................... 8 List of Tables Table 1. Latitude and longitude of sites surveyed at the Detroit River International Wildlife Refuge. ........... 8 Table 2. Native and non-native mussel species found during surveys. Numbers of empty shells are report unless otherwise noted. ............................................................................................................................... 8 Table 3. Species found during a meander survey of the beach adjacent to site 36 in the Fermi/Swan Creek area. All species were represented by shell only. ...................................................................................... 10 Table 4. Zebra mussel colonization data, including number of unionids colonized per site (ucz), mean number of zebra mussels per colonized unionid (zm/u), and the percentage of individuals at a site colo- nized (%cu). .............................................................................................................................................. 12 Table 5. Percent composition of each substrate size class within transects, estimated visually for each site. 13 Table 6. Habitat parameters measured at each site. ....................................................................................... 14 Abstract We performed surveys at 22 sites in the Detroit River International Wildlife Refuge (DRIWR) to determine the status of the northern riffleshell (Epioblasma torulosa rangiana) and other native mussel species (Unionidae). A total of 18 species were represented by live individuals and/or empty shell. No live individuals or empty shells of the northern riffleshell or rayed bean (Villosa fabalis) were found. Two empty shells of the state threatened wavy-rayed lampmussel (Lampsilis fasciola) were found at Site 28 off Grassy Island. The most abundant unionids found live were mapleleaf (Quadrula quadrula), threeridge (Amblema plicata), and lilliput (Toxolasma parvus). The occurrence of live lilliput mussels at the Fermi/Swan Creek area is of special note because there are relatively few known populations in Michigan. The prevalence of silt tolerant species and the high proportions of silt found at a majority of sites provides evidence that substrate composition is a factor contributing to the decline and/or exclusion of listed unionids in the DRIWR. Live zebra mussels were found attached to live unionid mussels at two sites in the Berenholz area and two sites in the Fermi/Swan Creek area. The presence of live zebra mussels attached to live uninoinds and recently dead unionid shells indicate a history impact at sites surveyed in the DRIWR. Sites 31 and 32 off Sugar Island may have the most potential to support northern riffleshell and other listed unionid species of the sites included in this study. Introduction fasciola), and species of special concern hickorynut (Obovaria olivaria), rainbow (Villosa iris), and round The Detroit River International Wildlife Refuge pigtoe (Pleurobema sintoxia (=coccineum)). (DRIWR) was created in 2001. It consists of islands, coastal wetlands, shoals, and riverfront lands including The mussel communities in the Detroit River have potential habitat for the federally listed as endangered experienced severe declines over the past 20 years due northern riffleshell (Epioblasma torulosa rangiana). It largely to the introduction of the zebra and quagga is North America’s only international wildlife refuge. mussels (Dreissena polymorpha and Dreissena The Refuge could potentially support some of the last bugensis) (Schloesser et. al. 1998). The northern populations of the federally endangered northern riffleshell had not been recorded in the Detroit River riffleshell and other rare unionids in Michigan. No since 1996; however, several recently dead valves of formal, complete USFWS survey of the Refuge has the northern riffleshell were found by Michigan been performed. Refuge species lists exist for plants, Natural Features Inventory (MNFI) staff in August of fish, birds, mammals, reptiles, amphibians and 2005, indicating the potential continued presence of invertebrates based on reports from other conservation this rare species. The status of native freshwater agencies and organizations. Mussels are absent from mussels, including the northern riffleshell, at the this list due to a lack of survey data. Detroit River International Wildlife Refuge needs to be ascertained in order to effectively manage these taxa. The Detroit River has historically supported some of The decline of the northern riffleshell over its range is the most diverse native freshwater mussel (Unionidae) cited in its Recovery Plan to be siltation, communities in Michigan, including globally impoundment, in-stream sand and gravel mining, and significant populations of rare mussel species. Surveys pollutants. Recovery objectives for the northern in 1982 revealed a very rich mussel community, riffleshell include maintaining and restoring viable including the northern riffleshell, a federally listed populations in 10 separate drainages. The Detroit endangered species; rayed bean (Villosa fabalis), a River is one of eight drainages that have been federal candidate species; snuffbox (Epioblasma identified as necessary for achieving recovery (U.S. triquetra), a state listed endangered species; and purple Fish and Wildlife Service 1994). wartyback (Cyclonaias tuberculata) and round hickorynut (Obovaria subrotunda), both state species Due to a limited number of mussel surveys in recent of special concern (Freitag 1984). In addition, several years, what we know of mussel populations in the other mussels identified as “species of greatest Detroit River is based mostly on surveys from the conservation need” have documented occurrences in 1980s and 1990s. Surveys of a dredging site near the the Detroit River and could be present in the DRIWR city of Gibraltar, now adjacent to the Detroit River (Michigan Natural Features Inventory conservation Refuge, revealed 22 species. These included northern database 2006). These are: the state endangered riffleshell, rayed bean, snuffbox, purple wartyback, salamander mussel (Simpsonaias ambigua), the state round pigtoe, round hickorynut, and rainbow (Freitag threatened wavy-rayed lampmussel (Lampsilis 1984). Surveys of Belle Isle in 1996 documented 100 Detroit River Mussels USFWS 06 - 1 empty shells of northern riffleshell and 24 empty shells in muskrat middens, are identified from the boat or of snuffbox.