|Scientific Name:||Cambarus cracens|
|Species Authority:||Bouchard & Hobbs, 1976|
|Red List Category & Criteria:||Endangered A2c ver 3.1|
|Assessor/s:||Cordeiro, J. & Thoma, R.F.|
|Reviewer/s:||Collen, B. & Richman, N.|
|Contributor/s:||Livingston, F., Livingston, F., Soulsby, A.-M., Batchelor, A., Dyer, E., Whitton, F., Milligan, H.T., Smith, J., Lutz, M.L., De Silva, R., McGuinness, S., Kasthala, G., Jopling, B., Sullivan, K. & Cryer, G.|
Cambarus cracens has been given a status of Endangered under criterion A2c. This species has a restricted range (extent of occurrence less than 100 km²) coupled with severe habitat disturbance through impoundment of a major river and drowning of its range, which has caused a reduction in the number of occurrences for this species such that repeated survey efforts have only uncovered extant populations in one site. It is estimated that the extent of occurrence has declined by between 50-80% over the last ten years and a similar rate of decline is expected in the population. Monitoring of the population is needed in order to understand current population trends and required conservation measures.
|Range Description:||This species is found in southeastern tributaries of Guntersville Lake, an impoundment on the Tennessee River in DeKalb and Marshall Counties, Alabama, USA (Fetzner 2008). The extent of occurrence of this species is estimated not to exceed 92 km².|
Native:United States (Alabama)
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||This species was only found recently at one site; it was formerly known from seven sites (G. Schuster and C. Taylor pers. comm. 2009).|
|Habitat and Ecology:||This species is found in permanent streams under rocks (Bouchard and Hobbs 1976); in clear, sluggish streams flowing over bedrock and sand, usually at depths of less than 0.6 m.|
|Major Threat(s):||The impoundment of the Tennessee River represents the major historical and present threat to this species. Reasons for decline (based on current versus historic records) are not known but the species is absent from nearly all historical sites where it was formerly known (G. Schuster and C. Taylor pers. comm. 2009). This has resulted in a reduction of over 80% of its historical range, assuming it was equally distributed across all known sites, and a decline that has been noted over the last 20 years. However the actual rate of decline over the last 10 years is not as high as 80% and more likely in the range of 50-70% (assuming a linear rate of decline).|
This species has been given a Global Heritage Status Rank of G1 by NatureServe (Taylor et al. 2007, NatureServe 2009) and endangered by the American Fisheries Society (Taylor et al. 2007).
Monitoring of the population trends of this species is needed.
Bouchard, R. W. and Hobbs, H. H. 1976. A New Subgenus and Two New Species of Crayfishes of the Genus Cambarus (Decapoda: Cambaridae) from the Southeastern United States. Smithsonian Contribution to Zoology 224: 1-24.
Fetzner, J.W. 2008. Crayfish Taxonomy Browser. Available at: http://iz.carnegiemnh.org/crayfish/NewAstacidea/infraorder.asp?io=Astacidea. (Accessed: 11.10.08).
IUCN. 2010. IUCN Red List of Threatened Species (ver. 2010.3). Available at: http://www.iucnredlist.org. (Accessed: 2 September 2010).
NatureServe. 2009. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. Internet
Taylor, C. A., Schuster, G.A., Cooper, J.E., DiStefano, R.J., Eversole, A.G., Hobbs III, H.H., Robison, H.W., Skelton, C.W. and Thoma, R.F. 2007. Conservation Status of Crayfish Species. Fisheries 32(8): 371-381.
|Citation:||Cordeiro, J. & Thoma, R.F. 2010. Cambarus cracens. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 18 June 2013.|
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