3.9 Snails
• residential and commercial development
• agriculture and aquaculture
• transportation and service corridors
• human intrusions and disturbance
• natural system modifcations
• pollution
• climate change and severe weather
Acid deposition from air pollution can afect soil calcium levels, which in turn may afect snails. An association has been made between snail abundance and diversity and avail- ability of calcium (from soil cations, detritus, plants) for regulation of bodily processes, reproduction, and shell building (Burch 1962; Fournie and Chetail 1984; Nekola 1999; Nekola and Smith 1999; Kalisz and Powell 2003; Hickman et al. 2003; Dourson 2013) . Snails play a critical role in concentrating calcium (in shells) which then becomes available to species in higher trophic levels, espe- cially birds that need calcium for egg shells (Skeldon et al. 2007) . Some research suggests that snail abundance and diversity can serve as an indicator for the efects of acid deposition (Hamburg et al. 2003; Skeldon et al. 2007) .
Contamination of freshwater habitats by chemicals, sediments, heavy metals and other substances has been recognized as a serious ecological impact to wildlife. Chemicals that afect survival and per- sistence (e.g., EDCs) in vertebrates and other mollusks can also afect freshwater snails (Fox 2005; Iguchi and Katsu 2008) . Tere is also growing concern for salinization of fresh- water systems from man-made sources such as road deicing, wastewater and mining efuents, oil and gas extraction methods, agricultural practices (Suski et al. 2012) , and upstream encroachment of salt water (salt wedge) facilitated by increased navigational dredging and sea level rise.
Flamed Tigersnail (Phil Myers, Museum of Zoology, University of Michigan-Ann Arbor) http://www.biokids.umich.edu/critters/Mollusca/ pictures/resources/contributors/phil_myers/ADW_ molluscs3_4_03/Anguispira_alternata3972/ Used under license CC BY-NC-SA 3.0
Species invasions have a demonstrated detrimental efect on the biodiversity of all mol- lusks, including snails (Lydeard et al. 2004; Lysne et al. 2008), directly through competition for
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2015 NC Wildlife Action Plan
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