Bithynia tentaculata has a high environmental impact in the Great Lakes.
Realized:
Between 1917 and 1968, the species richness of mollusks in Oneida Lake, NY declined by 15% as the faucet snail increased in abundance (Harman 2000). It is very probable that the faucet snail has particularly impacted pleurocerids, as seen with Elimia spp. in Oneida Lake, due to its higher growth rates (Tashiro and Colman 1982). However, after invasive zebra mussels (Dreissena polymorpha) colonized Oneida Lake, the density of faucet snails decreased and overall mollusk diversity diminished even further (Harman 2000). Similar effects occurred in Lake Ontario between 1983 and 2000 due to competition with invasive dreissenid mussels (Haynes et al. 2005).
After the introduction of B. tentaculata into the Erie Canal, the faucet snail began replacing two pleurocerid species, Elimia virginica and E. livescens (Jokinen 1992). Where the faucet snail has been observed in Lake Champlain, NY, it generally dominates gastropod assemblages (Vermont and New York State Departments of Environmental Conservation 2000).
In its native Eurasian habitat, the faucet snail is host to many different species of digeneans, cercariae, metacercariae, cysticercoids, and other parasites, some of which also parasitize fish and other wildlife (Mattison et al. 1995, Morley et al. 2004, Toledo et al. 1998). Bythinia tentaculata is known to be an intermediate host of three species of trematodes—Cyathocotyle bushiensis, Sphaeridiotrema globulus, and Leyogonimus polyoon—which can lethally parasitize birds when the snail is eaten (Herrmann and Sorensen 2009, Mitchell and Cole 2008, Sauer et al. 2007). The introduction of B. tentaculata has been linked to extensive mortality of migratory waterbirds in the Upper Mississippi River National Wildlife and Fish Refuge in Wisconsin due to its role as a host of C. bushiensis and S. globules (Herrmann and Sorensen 2009, Sauer et al. 2007). Between 2002 and 2006, over 20,000 migratory birds died at this location due to these parasites. Duck (Anas spp.) mortality in lower Quebec was credited to these two trematodes and their snail host (Ménard and Scott 1987), as was the death of 6,000-7,000 scaup (Aythya spp.) over a two month period at Lake Winnibigoshish in 2007 (Lawrence et al. 2009). A 1997 mass mortality event of over 10,000 water birds (particularly American coot, Fulica americana, and lesser scaup, Aythya affinis) was also reported at Shawano Lake, WI (Cole 2001, Cole and Franson 2006). Bythinia tentaculata occurs in this WI lake, and the deaths were primarily attributed to the presence of L. polyoon, the third trematode species hosted by B. tentaculata (Cole 2001, Cole and Franson 2006).
Potential:
Laboratory research on the impact of grazing by B. tentaculata indicated that it can have complex impacts on the periphyton community (Burgmer et al. 2010). Through direct and indirect effects, B. tentaculata grazing contributed to a shift from larger filamentous algae to small prostrate forms, was associated with a significant reduction in the biomass of heterotrophic nanoflagellates and ciliates, and was also linked to a weak decline in meiofauna biomass (Burgmer et al. 2010). Grazing by B. tentaculata, along with another snail species, was correlated with a decline in microalgal species richness (but increased evenness) and a significant reduction in the biomass microalgae, nanoautrophs, and bacteria (Burgmer et al. 2010).
Bythinia tentaculata often interacts with other nonindigenous species. It can serve as a food item for nonindigenous common carp, Cyprinus carpio (Ricciardi 2001), and is frequently found on introduced milfoil, Myriophyllum spicatum (Vincent et al. 1981), and among introduced dreissenid mussels (Ricciardi et al. 1997).
Bithynia tentaculata has a moderate socio-economic impact in the Great Lakes.
Realized:
Historically, this species has been known to infest municipal water supplies in abundance (Mills et al. 1993). The snail also has the potential to be a bio-fouling organism in underwater intakes and in swimming areas (Vermont and New York State Departments of Environmental Conservation 2000).
In areas of Wisconsin where the trematode parasites of B. tentaculata are causing large die-offs of waterbirds (see Environmental Impact above), these mass mortalities have fueled health concerns among waterfowl hunters and increased the difficulty of hunting game (Sauer et al. 2007). These mass mortality events have also resulted in restricted recreational access during periods of cleanup (Cole 2001, Lawrence et al. 2009, Sauer et al. 2007).
There is little or no evidence to support that Bithynia tentaculata has significant beneficial effects in the Great Lakes.
Potential:
The faucet snail has the potential to be a good biomonitor for contaminants such as cadmium, zinc, and methylmercury, owing to well-known correlations between environmental concentrations and snail tissue concentrations of these toxic compounds (Desy et al. 2000, Flessas et al. 2000).