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Pleurobema decisum

(I. Lea, 1831)

Southern Clubshell

G3Vulnerable Found in 6 roadless areas NatureServe Explorer →
G3VulnerableGlobal Rank
HighThreat Impact
Southern clubshell (Pleurobema decisum). Photo by U.S. Fish & Wildlife Service, Public Domain (U.S. Government Work), via ECOS.
U.S. Fish & Wildlife Service, https://www.usa.gov/government-works
Identity
Unique IDELEMENT_GLOBAL.2.1066298
Element CodeIMBIV35410
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryInvertebrate Animal
Endemicendemic to a single nation
KingdomAnimalia
PhylumMollusca
ClassBivalvia
OrderUnionoida
FamilyUnionidae
GenusPleurobema
Concept Reference
Williams, J. D., A. E. Bogan, R. S. Butler, K. S. Cummings, J. T. Garner, J. L. Harris, N. A. Johnson, and G. T. Watters. 2017. A revised list of the freshwater mussels (Mollusca: Bivalvia: Unionida) of the United States and Canada. Freshwater Mollusk Biology and Conservation 20:33-58.
Taxonomic Comments
Williams et al. (2017) place P. chattanoogaense into P. decisum. Genetic analysis is needed to compare this species with Pleurobema chattanoogaense and forms of the species (i.e., Pleurobema crebrivittatus and Pleurobema pallidovulvus) that are recognized by the U.S. Fish and Wildlife Service as synonyms.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2023-12-29
Change Date2023-12-29
Edition Date2023-12-29
Edition AuthorsCordeiro, J. (2011); rev. T. Cornelisse (2023)
Threat ImpactHigh
Range Extent20,000-200,000 square km (about 8000-80,000 square miles)
Number of Occurrences21 - 80
Rank Reasons
This species has experienced historical population declines and continues to be subject to many threats, but populations appear stable to increasing in recent years.
Range Extent Comments
This species occurs in the Mobile River basin of Mississippi, Alabama, and Georgia (Williams et al. 2008; USFWS 2019; GBIF 2023).
Occurrences Comments
This species is known from 47 occurrences using a 2 km separation distance and records from 2000-2023 and from 24 rivers, creeks, and their tributaries (USFWS 2019; GBIF 2023).
Threat Impact Comments
This species is threatened by sedimentation, nutrient, and chemical pollution from land conversion activities, including agriculture, oil and gas operations, and coal mining, dams and water diversions that change hydrological conditions, host fish distribution, and prevent habitat connectivity and recolonization, and habitat alteration due to climate change, including increased water temperatures and drought (USFWS 2008, 2019).
Ecology & Habitat

Description

This species has a thick shell, and heavy hinge plate and teeth. Shell outline is roughly rectangular, produced posteriorly with the umbos terminal with the anterior margin, or nearly so. The posterior ridge is nmoderately inflated and ends abruptly with little development of the posterior slope at the dorsum of the shell. Periostracum is yellow to yellow-brown with occasional green rays or spots on the umbo in young specimens (FWS, 2003).

Diagnostic Characteristics

Pleurobema decisum is distinguished from a closely related species, Pleurobema curtum by its elongate shape, lighter color, and presence of a well-defined sulcus in the latter species (U. S. Fish and Wildlife Service, 1993). Pleurobema chattanoogaensis of the upper Coosa River drainage is similar in shape and appearance, but may separated by the rounded posterior end of P. chattanoogaensis as compared to the sharp posterior end of P. decisum. Identification problems may also exist with specimens of Pleurobema murrayensis (Doug Shelton, pers. obs. 1996). The status of P. murrayensis is unknown and it may be extinct.

Habitat

Usually found in shoals highly oxygenated and moderate to fast moving streams to large rivers with sand and gravel substrate (USFWS 2000, 2019).

Reproduction

This species is a short-term brooder gravid from late spring to early summer (Haag and Warren 2003).
Other Nations (1)
United StatesN3
ProvinceRankNative
MississippiS1Yes
GeorgiaS1Yes
TennesseeSHYes
AlabamaS2Yes
Threat Assessments
ThreatScopeSeverityTiming
3 - Energy production & miningRestricted (11-30%)Serious - moderateHigh (continuing)
3.1 - Oil & gas drillingRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
3.2 - Mining & quarryingRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
7 - Natural system modificationsLarge (31-70%)Moderate or 11-30% pop. declineHigh (continuing)
7.2 - Dams & water management/useLarge (31-70%)Moderate or 11-30% pop. declineHigh (continuing)
9 - PollutionRestricted (11-30%)Serious - moderateHigh (continuing)
9.3 - Agricultural & forestry effluentsRestricted (11-30%)Serious - moderateHigh (continuing)
11 - Climate change & severe weatherLarge - restrictedModerate or 11-30% pop. declineHigh (continuing)
11.1 - Habitat shifting & alterationLarge - restrictedModerate or 11-30% pop. declineHigh (continuing)

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Roadless Areas (6)
Alabama (3)
AreaForestAcres
Blue MountainTalladega National Forest4,986
Cheaha ATalladega National Forest236
Oakey MountainTalladega National Forest6,129
Georgia (3)
AreaForestAcres
Foster BranchChattahoochee National Forest171
Ken MountainChattahoochee National Forest527
Pink KnobChattahoochee National Forest12,127
References (31)
  1. Biological Resources Division, USGS. 1997. Database of museum records of aquatic species. Compiled by J. Williams (USGS-BRD, Gainesville, FL).
  2. Freshwater Mollusk Conservation Society (FMCS). 2023. The 2023 checklist of freshwater bivalves (Mollusca: Bivalvia: Unionida) of the United States and Canada. Considered and approved by the Bivalve Names Subcommittee October 2023. Online: https://molluskconservation.org/MServices_Names-Bivalves.html
  3. Global Biodiversity Information Facility (GBIF). 2023. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2023).
  4. Graf, D.L. and K.S. Cummings. 2021. A 'big data' approach to global freshwater mussel diversity (Bivalvia: Unionoida), with an updated checklist of genera and species. Journal of Molluscan Studies 87(1):1-36.
  5. Haag, W. R. 2019. Reassessing enigmatic mussel declines in the United States. Freshwater Mollusk Biology and Conservation 22(2):43-60.
  6. Haag, W.R. and M.L. Warren, Jr. 2003. Host fishes and infection strategies of freshwater mussels in large Mobile Basin streams, USA. Journal of the North American Benthological Society 22(1):78-91.
  7. Johnson, P.D. and S.A. Ahlstedt. 2005. Results of a brief survey for freshwater mussels in the Yellow Creek Watershed, Lowndes County, Mississippi and Lamar and Fayette Counties, Alabama. Report to the U.S. Fish and Wildlife Service, Daphne, Alabama. Unpainated.
  8. Johnson, P.D., C. St. Aubin, and S.A. Ahlstedt. 2005. Freshwater mussel survey results for the Cherokee and Chattahoochee districts of the United States Forest Service in Tennessee and Georgia. Report to the U.S. Fish and Wildlife Service, Daphne, Alabama. 32 pp.
  9. Jones, R.L., W.T. Slack, and P.D. Hartfield. 2005. The freshwater mussels (Mollusca: Bivalvia: Unionidae) of Mississippi. Southeastern Naturalist, 4(1): 77-92.
  10. Mann, Tom. (Mississippi Natural Heritage Program. Mississippi Museum of Natural Science). 1997. Review and annotation of fish and mussel watershed distribution maps. Review requested by Ruth Mathews, TNC.
  11. Master, Lawrence L. (Chief Zoologist, TNC). 1997a. Review and annotation of fish and mussel watershed distribution maps. Reviews coordinated by Larry Master and Ruth Mathews, TNC.
  12. McGregor, S.W., P.E. O'Neil, and J.M. Pierson. 2000. Status of the freshwater mussel (Bivalvia: Unionidae) fauna of the Cahaba River system, Alabama. Walkerana, 11(26): 215-237.
  13. McGregor, S.W., T.E. Shepard, T.D. Richardson, and J.F. Fitzpatrick, Jr. 1999. A survey of the primary tributaries of the Alabama and Lower Tombigbee rivers for freshwater mussels, snails, and crayfish. Geological Survey of Alabama, Circular 196. 29 pp.
  14. Mirarchi, R.E., J.T. Garner, M.F. Mettee, and P.E. O'Neil. 2004b. Alabama wildlife. Volume 2. Imperiled aquatic mollusks and fishes. University of Alabama Press, Tuscaloosa, Alabama. xii + 255 pp.
  15. MolluscaBase eds. 2024. MolluscaBase. Accessed at https://www.molluscabase.org
  16. Shelton, Douglas N. Alabama Malacological Research Center, Mobile, AL. Personal communication.
  17. Turgeon, D. D., J. F. Quinn, Jr., A. E. Bogan, E. V. Coan, F. G. Hochberg, W. G. Lyons, P. M. Mikkelsen, R. J. Neves, C. F. E. Roper, G. Rosenberg, B. Roth, A. Scheltema, F. G. Thompson, M. Vecchione, and J. D. Williams. 1998. Common and scientific names of aquatic invertebrates from the United States and Canada: Mollusks. 2nd Edition. American Fisheries Society Special Publication 26, Bethesda, Maryland. 526 pp.
  18. United States Fish and Wildlife Service (USFWS). 2019. Southern Clubshell Recovery Plan Amendment. Atlanta, Georgia. 5 pp.<br/>
  19. U.S. Fish and Wildlife Service (USFWS). 1993. Endangered status for eight freshwater mussels and threatened status for three freshwater mussels in the Mobil River drainage. Final rule. Federal Register, 58(60): 14330-14340.
  20. U.S. Fish and Wildlife Service (USFWS). 1997. Draft Recovery Plan for the Mobile River basin aquatic ecosystem. U.S. Fish and Wildlife Service, Southeast Region, Atlanta, Georgia.
  21. U.S. Fish and Wildlife Service (USFWS). 2000. Recovery plan for the Mobile River basin aquatic ecosystem. U.S. Fish and Wildlife Service, Southeast Region, Atlanta, Georgia. 128 pp.
  22. U.S. Fish and Wildlife Service (USFWS). 2003. Endangered and Threatened Widlife and plants; proposed designation of critical habitat for three threatened mussels and eight endangered mussels in the Mobile River basin; proposed rule. Federal Register, 68(58): 14752-14832.
  23. U.S. Fish and Wildlife Service (USFWS). 2004. Endangered and Threatened Widlife and plants; designation of critical habitat for three threatened mussels and eight endangered mussels in the Mobile River basin; final rule. Federal Register, 69(126): 40083-40171.
  24. U.S. Fish and Wildlife Service (USFWS). 2019a. Finelined Pocketbook (<i>Hamiota</i> (=<i>Lampsilis</i>) <i>altilis</i>), Orangenacre Mucket (<i>Hamiota</i> (=<i>Lampsilis</i>) <i>perovalis</i>), Alabama Moccasinshell (<i>Medionidus acutissimus</i>), Coosa Moccasinshell (<i>Medionidus parvulus</i>), Southern Clubshell (<i>Pleurobema decisum</i>), Dark Pigtoe (<i>Pleurobema furvum</i>), Southern Pigtoe (<i>Pleurobema georgianum</i>), Ovate Clubshell (<i>Pleurobema perovatum</i>, Triangulua Clubshell (<i>Pleurobema greenii</i>), 5-year review: summary and evaluation. U.S. Fish and Wildlife Service, South Atlantic-Gulf Region (Region 2), Alabama Ecological Services Field Office, Daphne, Alabama. 69 pp.
  25. U.S. Fish and Wildlife Service (USFWS). 2023. Initiation of 5-Year Status Reviews for 67 Southeastern Species. Notice of initiation of reviews; <br/>request for information. Federal Register 88(91): 30324-30328.
  26. Vaughn, C.C. 2018. Ecosystem services provided by freshwater mussels. Hydrobiologia, 810: 15-27.
  27. Williams, J.D., A.E. Bogan, and J.T. Garner. 2008. Freshwater Mussels of Alabama & the Mobile Basin in Georgia, Mississippi & Tennessee. University of Alabama Press: Tuscaloosa, Alabama. 908 pp.
  28. Williams, J. D., A. E. Bogan, R. S. Butler, K. S. Cummings, J. T. Garner, J. L. Harris, N. A. Johnson, and G. T. Watters. 2017. A revised list of the freshwater mussels (Mollusca: Bivalvia: Unionida) of the United States and Canada. Freshwater Mollusk Biology and Conservation 20:33-58.
  29. Williams, J.D. and M.H. Hughes. 1998. Freshwater mussels of selected reaches of the main channel rivers in the Coosa drainage of Georgia. U.S. Geological report to U.S. Army Corps of Engineers, Mobile District, Alabama. 21 pp.
  30. Williams, J. D., M. L. Warren, Jr., K. S. Cummings, J. L. Harris, and R. J. Neves. 1993. Conservation status of freshwater mussels of the United States and Canada. Fisheries 18(9):6-22.
  31. Williams, J.D., S.L.H. Fuller, and R. Gracea. 1992a. Effects of impoundment on freshwater mussels (Mollusca: Bivalvia: Unionidae) in the main channel of the Black Warrior and Tombigbee Rivers in western Alabama. Bulletin of the Alabama Museum of Natural History 13:1-10.