Cambarus bartonii

Two subspecies of this species are recognized, Cambarus bartonii bartonii Fabricius 1798 and C. b. cavatus Hay 1902. Cambarus bartonii carinirostris Hay 1914 was elevated to species status by Thoma and Jezerinac (2000).

The nominal species widespread and abundant, found in New Brunswick, Canada, west to Kentucky and Tennessee, south to Alabama, Georgia, and South Carolina and east to the Atlantic Ocean. It likely also occurs (different morph- cavatus) Alabama, Indiana, Kentucky, Ohio and West Virginia. It is secure throughout its range and faces few threats although localized declines are occurring due to competetive exclusion by Cambarus robustus, and habitat degradation.

The nominal species found in New Brunswick, Canada, west to Kentucky and Tennessee, south to Alabama, Georgia, and South Carolina and east to the Atlantic Ocean (Hobbs, 1989). Taylor and Schuster (2004) cite Tennessee and northwestern Georgia to southwestern Virginia, West Virginia, and west to Kentucky for the subspecies cavatus. Eversole and Jones (2004) cite New Brunswick, Canada, to northern Georgia and eastern parts of Kentucky and Tennessee with populations in South Carolina and Georgia showing considerable variation across its range. In the southern portion of its range, it is confined to the Blue Ridge province of the Appalachian Highlands. In the northern portion of its range it occurs in the St. Lawrence basin in Ontario and Quebec to the southern Hudson Bay drainage.

Reeves et al. (2000) included Twin Snakes Cave in Dade Co., Georgia. It was recently found to be extant in the Catawba River basin in North Carolina but not extending into South Carolina (Alderman, 2005). It is found throughout most river basins in North Carolina, except the Broad and Catawba where it is primarily found in the western headwaters along teh eastern Continental Divide (Simmons and Fraley, 2010). In the Cumberland Plateau it occurs in tributaries of the Tennessee River upstream from Walden Gorge (Bouchard, 1974). In Kentucky, subspecies cavatus is widespread but sporadic in the eastern half with records from all major river drainages except the Green (Taylor and Schuster, 2004). Peake et al. (2004) collected this species in the upper Cumberland and upper Kentucky River basins in Kentucky. Jezerinac and Thoma (1984) cite Ohio distribution as Jefferson Co. Cambarus bartonii bartonii is stable in West Virginia and occurs throughout the Atlantic Slope (Potomac, James, Ridge and Valley, Allegheny Mountains, Appalachian Plateau regions) (Loughman and Welsh, 2010). Cambarus bartonii cavatus is stable in West Virginia and occurs in headwaters streams and wetlands throughout central and southern portions of the Ohio River direct drains, western portions of the Kanawha River, and southwestern Ohio River basins (Loughman and Welsh, 2010). In New York's Hudson River drainage, Smith (1979) added Rensselaer and Washington Cos., frequently only in the Poestenkill and upper Hoosic River system. In Vermont, it is known from the Hudson drainage (Battenkill) and the Champlain Basin (Kart et al., 2005). In Maryland, it is stable and is distributed widely from the eastern continental divide to the Coastal Plain as well as tributaries of the Potomac River in southern Maryland (Killian et al., 2010). Francois (1959) cites it in New Jersey in Bergen, Essex, Hunterdon, Mercer, Morris, Passaic, Sussex, Union, and Warren Cos.; as well as Bucks, Northampton, and Philadelphia Cos., Pennsylvania. In Massachusetts it is confined to tributaries flowing into the Hoosic River basin in the Hudson River drainage system, with a few records outside the Hoosic River that are the result of introduction (Smith, 2000). Horowitz and Flinders (2004) found it to be the most common species encountered (9 of 15 stations) in the Piedmont, Ridge and Valley and Highlands regions of New Jersey. It was recently documented in the vicinity of Plummers Island (bank of Potomac River), Montgomery Co., Maryland (Norden, 2008).

Overall this species faces few threats. In certain areas, it faces localized threats. Increasing range expansion of Cambarus robustus found to competitively exclude Cambarus bartonii in Ontario (Guiasu et al., 1996; Guiasu and Dunham, 1999). Localized declines can also be attributed to general habitat degradation and loss. Fish predation poses a greater threat to small rather than larger individuals (Englund and Krupa, 2000) and predation effects were larger for deeper pools than shallow ones (Englund, 1999).