Habitat

Great Plains and coniferous forest habitats show the most favorable living conditions for North American land snails while tundra, taiga, short grass prairie, and desert habitats show unfavorable living conditions (Solem, 1984).  Some species of land snails can still be found in unfavorable habitats, but the amount of species living there is significantly less than the species in favorable habitats.  Helicodiscus shimeki is primarily found in forest habitats. Most land snails that live in forest habitats live among low plant, leaf litter, or woody debris in the upper soil horizon (Hotopp, 2002).

The genus Helicodiscus has a vast range of dispersal in North America found in areas of Mexico expanding all the way up to Canada.  Some species of Helicodiscus are even found in the islands of Cuba and Jamaica (Pilsbry, 1998).  Helicodiscus shimeki is native to southern parts of Canada (Grimm, 2009) and spans down to Iowa (Poweshiek skipper project, 2005).  See Figure 1.

 

                                                                            Figure 1. Distribution map of Helicodiscus shimeki
                                                                            in 1962 (Hubricht, 1962). (Canada not shown)

The distribution of Helicodiscus shimeki has been updated since 1962 finding the snail in north eastern states including Maine (Martin, 2000) and in southern states like Kentucky (Nature Serve Explorer, 2009).  These new locations might be due to the snail migrating into new areas.  However, Helicodiscus shimeki is not a common land snail and is relatively small; the snail could have been easily overlooked in those areas in previous years. See Figure 2.

Figure 2. Distribution map of
Helicodiscus shimeki in 2011.