Plants and Animals
Vertigo modesta modesta A land snail (no common name)
Key Characteristics
The shell of Vertigo modesta modesta is elongate, quite small (.1 inches high), and of a medium to dark brown color, with 4-5 coarsely striated whorls and a rounded aperature showing 4 well-developed teeth in a cross formation.
Status and Rank
US Status: No Status/Not Listed
State Status: E - Endangered (legally protected)
Global Rank: G5T4
State Rank: S1 - Critically imperiled
Occurrences
| County | Number of Occurrences | Year Last Observed |
|---|---|---|
| Keweenaw | 2 | 1998 |
Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.
Habitat
In Michigan, two small colonies of this species have been found limited to cool, millimeter-deep soil accumulations among basalt boulders and clumps of fern (Polypodium vulgatum) at the base of talus slopes (Nekola 1998).
Natural Community Types
For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.
Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.
Management Recommendations
Further studies of Vertigo modesta modesta distribution are needed in order to implement effective management practices. As this species seems restricted to small, isolated colonies in very specific habitat, anthropogenic disturbance could easily impact the population. Protecting areas where suitable habitat exists may benefit the species.
Survey Methods
As visual detection of this species is difficult, specimens are collected by litter sampling in suitable habitat. Samples are thoroughly heat-dried, soaked in water for a number of hours to separate the various components, and finally passed through a series of sieves. The shells are then able to be hand-picked from the remaining sample material (Nekola 2003).
Litter sampling
Survey Period: From first week of April to first week of October
Time of Day: Daytime
References
Survey References
- Nekola, J.C. 2003. Large-scale terrestrial gastropod community composition patterns in the Great Lakes region of North America. Diversity and Distributions 9:55-71.
Technical References
- Burch, J.B. 1962. How to Know the Eastern Land Snails. William C. Brown Company Publishers, Dubuque. 214 pp.
- Hubricht, L. 1985. The Distributions of Native Land Mollusks of the Eastern US. Field Museum of Natural History. Fieldiana: Zoology, No. 24.
- Nekola, J.C. 1998. Terrestrial Gastropd Inventory of the Niagaran Escarpment and Keweenaw Volcanic Belt in Michigan's Upper Peninsula. Small Grants Program, 1998 Nongame Wildlife Fund, Natural Heritage Program, Michigan DNR, Lansing. 133pp.