Are Non-Native Gastropods a Threat to Endangered Lichens?

Extensive grazing by gastropods was found on endangered Boreal Felt Lichen (Erioderma pedicellatum) at Sixth Lake, Nova Scotia, in 2004. At least 80% of arboreal gastropods observed at the site were the introduced species Arion subfuscus. Subsequent surveys at five other locations in Nova Scotia showed 90% of arboreal gastropod individuals observed were introduced species. Potential impact on native lichen species, and in particular on rare and endangered species, is discussed