Plants and Animals
Vertigo nylanderi Deep-throat vertigo
Key Characteristics
The deep-throat vertigo is a small land snail with a cinnamon-colored cylindrical (beehive-shaped) shell that is 1.7 mm in height and 1 mm in width with 4.5 to 5 whorls. The growth lines on the shell are prominent. The aperture (main opening) has 6 strongly angular teeth or lamellae (calcareous plates, scales, or ridges on the inside of the aperture). The two lower palatal lamellae or teeth (on the outer lip or terminal part of the body whorl) are deeply inserted within the aperture. The two columellar lamellae or teeth located on the inside of the aperture on the main shell axis consist of a substantially larger lamella or tooth on top of a much smaller subcolumellar lamella. The two parietal lamellae or teeth on the inside or bottom of the main shell along the top of the aperture or opening also consist of a well-developed, larger parietal lamella or tooth adjacent to a thin, angular lamella.
Status and Rank
US Status: No Status/Not Listed
State Status: E - Endangered (legally protected)
Global Rank: G3G4 - Rank is uncertain, ranging from vulnerable to apparently secure
State Rank: S1? - Critically imperiled (inexact or uncertain)
Occurrences
| County | Number of Occurrences | Year Last Observed |
|---|---|---|
| Chippewa | 2 | 1998 |
| Delta | 1 | 1998 |
| Emmet | 1 | Historical |
| Mackinac | 3 | 2009 |
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 deep-throat vertigo occurs in calcareous fens with an open tamarack overstory, smaller shrubs of speckled alder and a groundlayer of sedges. The species is not found in densely forested tamarack swamps, cedar-dominated wetlands, or wetlands with Sphagnum moss. The species also is limited to areas of shallow limestone bedrock.
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
The deep-throat vertigo is vulnerable to foot and vehicle (ORV) traffic and road construction. Hydrological changes 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.
Litter sampling
Survey Period: From first week of June to fourth week of September
Humidity: Humid
Precipitation: Just after rain
Visual surveys
Survey Period: From first week of June to fourth week of September
Humidity: Humid
Precipitation: Just after rain
References
Survey References
- 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.
- Schilthuizen, M. and H.A. Rutjes. 2001. Land snail diversity in a square kilometer of tropical rainforest in Sabah, Malaysian Borneo. Journal of Molluscan Studies 67:417-423.
Technical References
- 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.