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North Dakota Species of Conservation Priority III

Fact Sheet
Scientific Name Quadrula
General Description Shell up to 4 inches in length. This species is a thick-shelled mussel. Tooth is well developed. Anterior rounded and posterior generally square. Two rows of raised nodules extending from hinge.
Status Year-round resident.
Abundance Rare.
Primary Habitat Streams with mud, sand or gravel bottoms.
Federal Status None.
Reason for Designation Changes in land use in and around these rivers, most notably agriculture, and impoundment of river systems have impacted beds of these mussels. They are also of commercial value and are protected from harvest in North Dakota.



(Photos courtesy of Prairie Waters Education and Research Center - Valley City University)

Locations and Conditions of Key Habitat

Preferred Habitat

The Mapleleaf is found in medium to large rivers with gravel or mud bottoms. Usually associated with deeper water in areas where the channel width is 30-88m wide.

Key Areas and Conditions for Mapleleaf in North Dakota

The Red River is the only place where this species has ever been documented alive. This species may also be found in parts of the Sheyenne River.

Problems Which May Affect this Species


Impoundment of the Red River and its tributaries has changed the flow regime and increased sediment deposits making many areas in the river unsuitable to the Mapleleaf. Impoundments also impede the movement of host fish needed for reproduction and dispersal. Agricultural practices within the basin have reduced suitable habitat in the river. Runoff from treated fields into the river decreases water quality. Ditches used to drain wetlands and fields contribute to runoff and sedimentation in the Red River and its tributaries. These practices may contribute to this species’ decline. Freshwater mussels are generally intolerant of pollution.

Other Natural or Manmade Factors

The Mapleleaf is considered a commercially valuable species. It is presently illegal to collect mussels for commercial use, but this practice may occur in parts of its range.

Research and Survey Efforts

Current Research or Surveys

  • No current research or survey efforts are on-going in this species range.

Previous Research or Surveys

  • Cvancara conducted a state-wide survey of the mussels of North Dakota in 1978.
  • The North Dakota Game and Fish Department revisited Cvancara’s sites in 1990.
  • Valley City State University revisited Cvancara’s sites and surveyed additional sites in 2008
  • The NDDH conducted freshwater mussel surveys for state waters as a segment of its Index of Biotic Integrity (IBI) work.

Additional Research or Surveys Needed

  • A monitoring protocol for mussel species has been developed for the North Dakota Game and Fish Department under the SWG program. Implementation of this monitoring protocol is a future goal.

Management Recommendations

  • Develop buffers along riparian areas.
  • Work with partners to reduce the use of chemical near waterways.
  • Work with partners to reduce wetland drainage.
  • Remove river impoundments where possible.
  • Work with partners to maintain instream flows.

Monitoring Plans

A monitoring protocol has been developed for the North Dakota Game and Fish Department under the SWG program. Implementation of this monitoring protocol is a future goal.

2005-2015 Progress

SWG T-24-R A Two Phase Population Survey of Mussels in North Dakota Rivers provided important information on the distribution of this species. Work to implement a monitoring protocol for mussels species will is a goal of the revised Wildlife Action Plan.

Range Map

Note: A listing of works consulted when compiling the information on this page may be found in the 2015 State Wildlife Action Plan.