title: Competitive replacement of invasive congeners may relax impact on native species: interactions among zebra, quagga, and native unionid mussels.
abstract: Determining when and where the ecological impacts of invasive species will be most detrimental and whether the effects of multiple invaders will be superadditive, or subadditive, is critical for developing global management priorities to protect native species in advance of future invasions. Over the past century, the decline of freshwater bivalves of the family Unionidae has been greatly accelerated by the invasion of Dreissena. The purpose of this study was to evaluate the current infestation rates of unionids by zebra (Dreissena polymorpha) and quagga (D. rostriformis bugensis) mussels in the lower Great Lakes region 25 years after they nearly extirpated native unionids. In 2011-2012, we collected infestation data for over 4000 unionids from 26 species at 198 nearshore sites in lakes Erie, Ontario, and St. Clair, the Detroit River, and inland Michigan lakes and compared those results to studies from the early 1990 s. We found that the frequency of unionid infestation by Dreissena recently declined, and the number of dreissenids attached to unionids in the lower Great Lakes has fallen almost ten-fold since the early 1990s. We also found that the rate of infestation depends on the dominant Dreissena species in the lake: zebra mussels infested unionids much more often and in greater numbers. Consequently, the proportion of infested unionids, as well as the number and weight of attached dreissenids were lower in waterbodies dominated by quagga mussels. This is the first large-scale systematic study that revealed how minor differences between two taxonomically and functionally related invaders may have large consequences for native communities they invade.
authors.affiliation: Great Lakes Center, SUNY Buffalo State, Buffalo, New York, United States of America; The Research Foundation of The State University of New York, SUNY Buffalo State, Office of Sponsored Programs, Buffalo, New York, United States of America.
authors.forename: Lyubov E
authors.initials: LE
authors.lastname: Burlakova
authors.affiliation: Great Lakes Center, SUNY Buffalo State, Buffalo, New York, United States of America.
authors.forename: Brianne L
authors.initials: BL
authors.lastname: Tulumello
authors.affiliation: Great Lakes Center, SUNY Buffalo State, Buffalo, New York, United States of America.
authors.forename: Alexander Y
authors.initials: AY
authors.lastname: Karatayev
authors.affiliation: Cleveland State University, Department of Biological, Geological, and Environmental Sciences, Cleveland, Ohio, United States of America.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Krebs
authors.affiliation: U.S. Geological Survey, Great Lakes Science Center, Ann Arbor, Michigan, United States of America.
authors.forename: Donald W
authors.initials: DW
authors.lastname: Schloesser
authors.affiliation: Great Lakes Center, SUNY Buffalo State, Buffalo, New York, United States of America; Central Michigan University, Institute for Great Lakes Research, Biology Department, Mount Pleasant, Michigan, United States of America.
authors.forename: Wendy L
authors.initials: WL
authors.lastname: Paterson
authors.affiliation: Central Michigan University, Institute for Great Lakes Research, Biology Department, Mount Pleasant, Michigan, United States of America.
authors.forename: Traci A
authors.initials: TA
authors.lastname: Griffith
authors.affiliation: Central Michigan University, Institute for Great Lakes Research, Biology Department, Mount Pleasant, Michigan, United States of America.
authors.forename: Mariah W
authors.initials: MW
authors.lastname: Scott
authors.affiliation: University of Toledo, Department of Environmental Science, Lake Erie Center, Toledo, Ohio, United States of America.
authors.forename: Todd
authors.initials: T
authors.lastname: Crail
authors.affiliation: Central Michigan University, Institute for Great Lakes Research, Biology Department, Mount Pleasant, Michigan, United States of America.
authors.forename: David T
authors.initials: DT
authors.lastname: Zanatta
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D016022:Case-Control Studies; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy / Q000473:pathology; D009367:Neoplasm Staging; D009369:Neoplasms / Q000188:drug therapy* / Q000473:pathology; D011379:Prognosis; D011446:Prospective Studies; D015996:Survival Rate