Bellamya chinensis is a relatively large snail species that can reach very high densities of up to 40 per m² (Soes et al., 2011; Johnson et al., 2009). While negative impacts on native snail species and ecosystems are expected (Bury et al., 2007) very little is known about its ecological impacts and significance in invaded systems (Johnson et al., 2009; Solomon et al., 2010; Soes et al., 2011)
Competition: Presence of B. chinensis was found to cause substantial declines in the growth and abundance of native Physella gyrina and Lymnaea stagnalis snails in mesocosm experiments, probably through competition for food (Johnson et al., 2009). However such negative impacts on native gastropod assemblages have not yet been confirmed in field studies. Solomon et al. (2010) found no difference in snail assemblage structure associated with B. chinensis presence or abundance at the scale of an entire lake, although some native snail species tended not to occur at sites where B. chinensis was abundant.
Ecosystem change: In a mesocosm experiment B. chinensis grazing was found to reduce algal biomass, algal species composition and increase the N: P ratio in the water column. Such effects may have important ecological consequences (Johnson et al., 2009).
Interaction with other invasive species: In a mesocosm experiment in Wisconsin, the dual effects of predation by an invasive crayfish (Orconectes rusticus) and competition by B. chinensis were found to have more severe impacts on native snail species than either invader alone. Due to its large size and thicker shell B. chinensis was less vulnerable to predation by this crayfish. The combined impact of both invasive species was found to extirpate one native snail species and reduce the abundance of a second by >95%. This may be because O. rusticus reduces native snail abundance via predation but has limited effects on B. chinensis, thus promoting additional food resources for B. chinensis (Johnson et al., 2009).
An experimental study in Washington suggests that B. chinensis may facilitate establishment and exacerbate the establishment success and ecological impacts of an invasive crayfish (Orconectes virilis) by providing an abundant prey resource (i.e. invasional meltdown). This hypothesis requires further research and testing (Olden et al., 2009).
Human health: B. chinensis is also the host for several helminth parasites that affect humans in native Asia. Thus it may serve as a vector for parasites and diseases, including human intestinal fluke (Chung & Jung, 1999; Havel, 2010; NAPIS, 2010). However there is little data to support this (Soes et al., 2011), and there have been no reported cases involving human intestinal fluke transmitted by B. chinensis in the United States (Bury et al., 2007).
Human nuisance: Shells may clog the screens of water intake pipes and thus inhabit the flow of water (AIS, 2005). Additionally, dead and decaying shells can form large windrows on lake shores, which is viewed as a nuisance by residents in some regions (Bury et al., 2007). In the Laurentian Great Lakes, fisherman often made seine hauls containing “2 tons” of snails, which were likely B. chinensis or B. japonica (Wolfert & Hiltunen, 1968).
Other: B. chinensis were found to provide a novel food resource for both native and invasive crayfish in Washington, despite their thick shell and trapdoor defense behaviour. For all snail size classes native Pacifastacus leniusculus was able to consume greater numbers of snails than an invasive crayfish species. Whether this translates into P. leniusculus having a competitive advantage over invasive crayfish in a natural setting is unknown (Olden et al., 2009).