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Non-native slugs, such as Arion, are becoming a concern for land managers in Nova Scotia, Canada, particularly in forested wetlands. They appear to have a highly diverse diet and may pose a particular risk to native slug species and to rare or at-risk lichens. We provide novel information on the distribution, abundance, arboreal tendencies, and seasonality of slugs in forested wetlands across southwestern Nova Scotia. We collected a total of 402 slugs representing seven species including two native species, Pale Mantleslug (Pallifera dorsalis) and Meadow Slug (Deroceras laeve), and five non-native Arion taxa. The three most abundantly caught taxa were Northern Dusky Arion (Arion fuscus), D. laeve, and Western Dusky Slug (Arion subfuscus). Arion fuscus and D. laeve were collected on the forest floor and on lichen-bearing trees, while A. subfuscus was collected only on the ground. All three taxa showed differences in collectability between July and September and low arboreal tendencies. We highlight that further studies are needed to better understand the biology and ecology of this largely neglected invertebrate group that seems to be dominated by non-native Arion species in the study region. Such information is crucial for conservationists and forest managers untangling the question of how non-native slugs affect native slug taxa and other groups including at-risk lichens. [ABSTRACT FROM AUTHOR]

The Chinese mystery snail, Cipangopaludina [=Bellamya] chinensis, is documented for the first time in the Saint John River, New Brunswick, a watercourse which drains the largest watershed in Atlantic Canada. This is the first non-native mollusc known to be established in the Saint John River system. Although significant ecosystem effects of the species seem unlikely, possible introduction of C. chinensis via boat traffic emphasizes the need for boater education combined with monitoring of the Saint John River system for potentially more troublesome non-native species, including the zebra mussel, Dreissena polymorpha. Review of published records and museum collections for Atlantic Canada show C. chinensis has been reported from 13 freshwater wetlands and waterbodies in New Brunswick, Nova Scotia and Newfoundland since 1955. The species remains extant in at least 10 of these sites and is clearly more widespread in the region than the single previously published report would suggest. [ABSTRACT FROM AUTHOR]