Vertigo pygmaea
Crested vertigo

Key Characteristics

This is a tiny land snail with a chestnut brown-colored cylindrical (beehive-shaped) shell that is 1.8 - 2.0 mm in height and 1 - 1.1 mm in width with 5 whorls. The last whorl has a strong, pale crest just behind the aperture lip.

Status and Rank

  • State Status: SC
  • State Rank: S1S2
  • Global Rank: G5

Occurrences

County NameNumber of OccurrencesYear Last Observed
Chippewa11998
Mackinac3
Distribution map for Vertigo pygmaea

Updated 1/31/2017. 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

The crested vertigo is found in a calcareous coastal fen dominated by sedges, especially near the shore. It also is often found thriving on roadsides and other disturbed habitats, including urban centers.

Natural Community Types

Methodology

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

The crested vertigo is vulnerable to foot and vehicle traffic. Hydrological changes should be strictly avoided. Use of prescribed fire in occupied sites should be avoided, if possible, or prescribed fire should be applied very conservatively, leaving multiple refugia and using a burn interval of at least 15 years.

Active Period

Active from first week of June to fourth week of September

Survey Methods

Surveys can be conducted anytime during the growing season, but are most successful in spring and fall following rain showers or when the soil is moist, and during higher relative humidity conditions and cooler temperatures. Visual surveys consist of looking for individuals crawling on the ground, in moist leaf litter, and on or under woody debris. Litter sampling consists of collecting soil and leaf litter samples in the field and drying, sifting and looking for snail shells in the litter samples in the laboratory.

Page Citation

Michigan Natural Features Inventory. 2007. Rare Species Explorer (Web Application). Available online at http://mnfi.anr.msu.edu/explorer [Accessed Jul 20, 2017]

References

Survey References

Technical References

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