Habitat
"I'm always here!"
One important feature of any land snail is its mantle, a swatch of skin that hangs on each side of the organism. Besides housing its lung, necessary for the completely terrestrial Vertigo morsei, the outer portion of the mantle cavity secretes a protective calcium carbonate shell over the head-foot and visceral mass (inner portion containing digestive, circulatory, respiratory, and reproductive organs). (Hickman, et al. 2009) Therefore, one of the limiting factors in location is the amount of available calcium, though you can find snails in areas with soil poor in this element if the surrounding plant life eaten by the snail can provide it. (Vertigo morsei Sterki 2009)
Any land snail also needs adequate moisture for locomotion and reproduction. They create mucous trails when they move, and much of the mucous is made of water. Snail eggs can be at risk of drying out, so you will find them under stones, logs, or leaf litter. (Vertigo morsei Sterki 2009)
The average Six-whorl Vertigo prefers the underside of dead wood or fallen leaves, found at the edge of a pond or marsh, and many populations like relatively higher humidity along with cooler temperatures. (Pilsbry 1948)
Nekola and Coles (2010) added to the habitat knowledge of this species by adding that "Populations occur in humid, aerated, well-decomposed leaf litter often overlying marl or carbonate bedrock in highly calcareous open wetlands including fens, alvars, and wet prairie. They may also be occasionally found crawling on Juncus stems."
Sufficient shelter is a crucial aspect for the successful life of any land snail. Refuges provide protection from extreme weather, water loss, and predation. These places will include the above mentioned and even crevices in tree bark or rocks. (Vertigo morsei Sterki 2009)
Knowledge about this snail's location has changed in recent years. At first, it was found only in New York, New Jersey, Michigan, Indiana, and Illinois. (Burch 1962) It has now been recorded to reside in Wisconsin, Minnesota, Massachusetts, Maine, and even Ontario, Canada. (Vertigo morsei Sterki 2009)
As noted, its distribution is still very scattered, and unfortunately, its habitat will probably continue to be threatened by wetland draining. To retain the populations of the Six-whorl Vertigo, fragile marshes need to be preserved. Since snails depend on the quality of the soil for calcium, shelter, and moisture, any land-use activities need to be limited by humans, especially in areas where there has been documentation of this snail. (Cordeiro 2010)
Vertigo morsei is vulnerable to excessive trampling of the ground by hikers and off-road vehicles. It has also been shown that prescribed burns reduce the species numbers in grasslands by decreasing the richness of the soil and the architecture of the ground in the area. (Vertigo morsei Sterki 2009)
Many other creatures prefer the same moist environment as Vertigo morsei. Other land snails, insects, salamanders, and plants can be found there. Life isn't always easy for a terrestrial snail. It completes one of its roles in the environment by becoming a common meal for birds, small mammals, amphibians, reptiles, and insects. (Burch 1962)
To find out more about this snail's distribution in Michigan and additional facts about the species, go to this website provided by Michigan State University.
On to Adaptation!