Obovaria olivaria
Hickorynut

Key Characteristics

The hickorynut is a medium sized (to 4 inches) mussel with a smooth, somewhat inflated, oval or oblong shell. The shell is yellowish brown or greenish with faint rays that are visible on young individuals. The beaks are large and the beak sculpture consists of 4 to 5 subtle double-loops and is usually only visible on very young individuals. Cardinal teeth are aligned horizontally and are relatively small and triangular. The nacre is white.

Status and Rank

  • State Status: E
  • State Rank: S1
  • Global Rank: G4

Occurrences

County NameNumber of OccurrencesYear Last Observed
Macomb22009
Menominee21977
Monroe31935
Ottawa71959
Saginaw12001
Washtenaw11996
Wayne82007
Distribution map for Obovaria olivaria

Updated 7/21/2017. 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 Hickorynut is found in large rivers and lakes in sand or sand and gravel substrates.

Specific Habitat Needs

Sandy, gravel substrates needed in River (5th-6th order), Pool, River (5th-6th order), Run

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

Like other mussels, threats to the hickorynut include: natural flow alterations, siltation, channel disturbance, point and non-point source pollution, and exotic species. Maintenance or establishment of vegetated riparian buffers can help protect mussel habitats from many of their threats. Control of zebra mussels is critical to preserving native mussels. And as with all mussels, protection of their hosts habitat is also crucial.

Survey Methods

Page Citation

Michigan Natural Features Inventory. 2007. Rare Species Explorer (Web Application). Available online at http://mnfi.anr.msu.edu/explorer [Accessed Nov 21, 2017]

More Information

See MNFI Species Abstract

References

Survey References

Technical References

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