Distribution ³

Global Range: (20,000-200,000 square km (about 8000-80,000 square miles)) Historically, the rabbitsfoot occurred in the lower Great Lakes sub-basin and Mississippi River Basin from 137 streams in 15 states including: the lower Great Lakes sub-basin, Ohio River system, Cumberland River system, Tennessee River system, lower Mississippi River sub-basin, White River system, Arkansas River system, Red River system. Reports from Nebraska, Michigan, Iowa, and New York, are questionable, at best (Butler, 2005). It is found throughout the Ohio River drainage from headwaters in Pennsylvania to the mouth of the Ohio River (Ortmann, 1919; Cummings and Mayer, 1992). It is widespread in the Cumberland River drainage downstream of Cumberland Falls (Cicerello et al., 1991; Parmalee and Bogan, 1998) and in the Tennessee River drainage from headwaters in southwestern Virginia downstream to the mouth of the Tennessee River (Ahlstedt, 1992a; 1992b; Parmalee and Bogan, 1998). It also occurs in some tributaries of the lower Mississippi River from southeastern Kansas (Murray and Leonard, 1962) and Missouri (Oesch, 1995) south to Arkansas (Harris and Gordon, 1990), northern Louisiana (Vidrine, 1993) and Mississippi (Jones et al., 2005). he rabbitsfoot is believed extirpated from Georgia and West Virginia, while its continued existence in several other states (e.g., Alabama, Kansas, Louisiana, Mississippi, Missouri) is extremely perilous (Butler, 2005).

Habitat ⁴

Habitat Type: Freshwater

Comments: According to Gordon and Layzer (1989) the typical habitat for this species is small to medium rivers with moderate to swift currents, and in smaller streams it inhabits bars or gravel and cobble close to the fast current. Found in medium to large rivers in sand and gravel (Cummings and Mayer, 1992). It has been found in depths up to 3 m (Parmalee, 1967). Despite their streamlined appearance, specimens are more often found fully exposed lying on their sides on top of the substrate (Walters, pers. obs.).

Iucn red list assessment ⁵

• Needs updating

Assessor/s

Nature serve conservation status ⁶

Rounded Global Status Rank: T3 - Vulnerable

Reasons: Although widely distributed, occurrences are spotty, and it has been eliminated from a portion of its historic range, and is on many state endangered species lists.

Intrinsic Vulnerability: Moderately vulnerable

Comments: The majority of the remaining rabbitsfoot populations are generally small and geographically isolated. The factor that most noticeably results in population isolation is impoundment but may also include stream reaches heavily impacted by toxic effluents and contaminated sediments. The patchy distributional pattern of populations in short river reaches makes them much more susceptible to extirpation due to the lack of recolonization from other populations. Single catastrophic events, such as toxic chemical spills, could cause the extirpation of small, isolated rabbitsfoot occurrences. The likelihood is high that some rabbitsfoot populations are below the effective population size (EPS) (Soulé, 1980) required to maintain long-term genetic and population viability. Recruitment reduction or failure is a potential problem for many small rabbitsfoot populations rangewide, a potential condition exacerbated by its reduced range and increasingly isolated populations. Without the level of genetic interchange the species experienced historically (i.e., without barriers such as reservoirs), small isolated populations that may now be comprised predominantly of adult specimens could be slowly dying out (Butler, 2005).

Environmental Specificity: Narrow. Specialist or community with key requirements common.

Comments: The decline in the overall range of this species suggests that it is not very tolerant to poor water quality. The sites where it still occurrs are usually high quality streams with little disturbance to the substrate or degradation of water quality.

Other Considerations: QUADRULA CYLINDRICA CYLINDRICA was listed as Threatened by the freshwater mussel subcommittee of the endangered species committee of the American Fisheries Society (Williams, et al. 1993). It has been eliminated from much of this range and is on many state endangered species lists including: Illinois, Indiana, Missouri, and Ohio (Cummings and Mayer, 1992).

Threats ⁷

Degree of Threat: Very high - high

Comments: Most of the information below is taken directly from Butler (2005) and the sources cited therein:
The chief causes of this decline are impoundments, channelization, chemical contaminants, mining, and sedimentation (Neves, 1991, 1993; Williams et al., 1993; Neves et al., 1997; Watters, 2000). Bourgeoning human populations will invariably increase the likelihood that many if not all of the factors in this section will continue to impact rabbitsfoot populations. The decline, extirpation, and extinction of mussel species is overwhelmingly attributed to habitat alteration and destruction (Neves, 1993), primarily manifest through impounding riverine systems. Historical population losses due to impoundments have probably contributed more to the decline and imperilment of the rabbitsfoot than any other single factor. Dams interrupt most of a river's ecological processes by modifying flood pulses; controlling impounded water elevations; altering water flow, sediments, nutrients, and energy inputs and outputs; increasing depth; decreasing habitat heterogeneity; decreasing stability due to subsequent sedimentation; blocking host fish passage; and isolating mussel populations from fish hosts. Impoundments also dramatically modify riffle and shoal habitats and result in the loss of mussel resources, especially in highly diverse larger rivers. The reproductive process of riverine mussels is generally disrupted by impoundments. No exception to this rule, the rabbitsfoot does not occur in reservoirs lacking riverine characteristics and is unable to successfully reproduce and recruit under reservoir conditions. It may persist and even exhibit some level of recruitment, however, in some large rivers with locks and dams if riverine habitat remains (e.g., Ohio, Tennessee Rivers). In addition, dams can also seriously alter downstream water quality and riverine habitat, and negatively impact or eliminate tailwater mussel populations. Seasonally altered flow regimes from dams, even when thermally conducive for riverine mussel populations, may also preclude successful recruitment in tailwater reaches. Large river habitat throughout nearly the entire range of this species has been impounded leaving generally short, isolated patches of vestigial habitat mostly in tailwaters below certain dams. The majority of the main stems of the Ohio, Cumberland, Tennessee River, and White Rivers and many of their largest tributaries, including reaches that were once strongholds for the rabbitsfoot, are now impounded and in many cases impacted by tailwater conditions unsuitable for this species. Dams on many streams in the Cumberlandian region have directly destroyed rabbitsfoot habitat. These include nine on the main stem Tennessee River, and others on the Holston, Little Tennessee, Clinch, Elk, and Duck Rivers, and Bear Creek). Dredging and channelization activities have profoundly altered riverine habitats nationwide. Channelization impacts a stream's physical (e.g., accelerated erosion, increased bedload, reduced depth, decreased habitat diversity, geomorphic instability, riparian canopy loss) and biological (e.g., decreased fish and mussel diversity, changed species composition and abundance, decreased biomass, and reduced growth rates) characteristics. Contaminants in point and non-point discharges can degrade water and substrate quality, and adversely impact or completely destroy mussel populations. The effects of contaminants (e.g., metals, chlorine, ammonia) are especially profound on juvenile mussels. Heavy metal-rich drainage from coal mining and associated sedimentation has adversely impacted many drainages with rabbitsfoot populations, including portions of the upper Ohio River system in Kentucky, Pennsylvania, and West Virginia; the lower Ohio River system in eastern Illinois; the Rough River drainage in western Kentucky; and the upper Cumberland River system in Kentucky and Tennessee. Various mining activities take place in other systems that have affected or potentially continue to impact rabbitsfoot populations. Negative impacts associated with gravel mining include stream channel modifications (e.g., altered habitat, disrupted flow patterns, sediment transport), water quality modifications (e.g., increased turbidity, reduced light penetration, increased temperature), macroinvertebrate population changes (e.g., elimination, habitat disruption, increased sedimentation), and changes in fish populations (e.g., impacts to spawning and nursery habitat, food web disruptions). Sedimentation, including siltation, has been implicated in the decline of stream mussel populations. Many rabbitsfoot streams in the Midwest and Southeast have increased turbidity levels due to siltation. It produces conglutinates that appear to function in attracting visual-feeding host fishes. Such a reproductive strategy depends on clear water when mussels are releasing glochidia. Agricultural activities produce the most significant amount of sediment that enters streams. Developmental activities may impact streams where adequate streamside buffers are not maintained and erosion of impacted land is allowed to freely enter streams. These may include highway construction, building construction, general infrastructure (e.g., utilities, sewer systems), and recreation facilities (e.g., golf courses). Water withdrawals for agricultural irrigation, municipal, and industrial water supplies are an increasing concern for all aquatic resources and are directly correlated with expanding human populations. This impact has the potential to be another (in addition to increased level of general development) problem for the substantial rabbitsfoot population in the Duck River. Numerous streams having rabbitsfoot populations were actively worked by "pearlers" (e.g., Little Miami, Cumberland, Obey, Stones, Tennessee, French Broad, Clinch, Elk, Duck, St. Francis, White, Buffalo, Black, Ouachita Rivers; Caney Fork). However, the rabbitsfoot was never a valuable shell for the commercial pearl button industry nor the cultured pearl industry, and hence these activities were probably not significant factors in its decline. The alien species that may pose the most significant threat is the zebra mussel, Dreissena polymorpha (Pallas, 1771). The zebra mussel invasion poses a threat to mussel faunas in many regions, and species extinctions are expected as a result of its continued spread in the eastern United States (Ricciardi et al., 1998). Overlapping much of the current range of the rabbitsfoot, zebra mussels have been detected and/or are established in rabbitsfoot streams (e.g., Ohio, Allegheny, Green, Tennessee, White Rivers; French, Bear Creeks). Populations appear to be maintained primarily in streams with barge navigation. The Asian clam, Corbicula fluminea (Müller, 1774), has spread throughout the Mississippi River Basin since its introduction into the basin in the mid-1900s. This species has been implicated as a competitor with native mussels, particularly juveniles, for resources such as food, nutrients, and space (Neves and Widlak, 1987, Leff et al., 1990). According to Strayer (1999), dense populations of Asian clams may ingest large numbers of unionid sperm, glochidia, and newly-metamorphosed juveniles. He also thought they actively disturb sediments, so dense populations may reduce habitat for juvenile native mussels. Periodic dieoffs of Asian clams may produce enough ammonia and consume enough DO to kill native mussels (Strayer, 1999). Native to China, the black carp (Mylopharyngodon piceus) is a potential threat to the rabbitsfoot (Strayer, 1999). The round goby (Neogobius melanostomus) is another alien invader fish species released in the 1980s into the Great Lakes in ballast waters originating in southeastern Europe (Strayer, 1999). The harvest of Cumberlandian Region mussel species for commercial purposes is well documented (Downing and Downing, 2001). It is doubtful, however, that this species has ever been overly exploited for pearling, pearl buttons, cultured pearls, or any other exploitative activity (USFWS, 2004).

Trends ⁸

Global Short Term Trend: Decline of 50-70%

Comments: Based on historical and current data, the rabbitsfoot is declining rangewide and is now extant only in 46 of 137 streams of historical occurrence, representing a 66% decline. Further, in the streams where it is extant, populations with few exceptions are highly fragmented and restricted to short reaches. Realistically, much more than 66% of the species' historically available habitat no longer supports populations. Total range reduction and overall population loss for the rabbitsfoot realistically approaches--if not exceeds--90%. Ten of the 15 states from which the rabbitsfoot is historically known consider it endangered (Illinois, Indiana, Kansas, Mississippi, Ohio, and Pennsylvania), threatened (Kentucky and Tennessee), special concern (Arkansas), or have assigned it uncategorized conservation status (Alabama). The rabbitsfoot is believed extirpated from Georgia and West Virginia. Five streams in addition to a canal historically had populations in the lower Great Lakes sub-basin, but only a single stream population remains today. The species has experienced a 75% decline in the Ohio River system. The compilation of distributional information herein abundantly indicates a severe reduction in range of the rabbitsfoot over the past 40 years (Butler, 2005).

Global Long Term Trend: Decline of 70-90%

Comments: The historical museum data (~pre-1980) indicates that good rabbitsfoot populations occurred in at least the Ohio River, Walhonding River, Big Sandy River, Scioto River, Olentangy River, Nolin River, Wabash River, North Fork Vermilion River, Obey River, Tennessee River, White River, Black River, Spring River, Strawberry River, Illinois River, Glover River, and Cossatot River. Based on information gleaned from museum and historical literature records, a potential argument can be made for localized but not overall abundance of this species historically. Populations of the rabbitsfoot were last reported decades ago (~40+ years) from about one-third of the streams where it historically occurred (e.g., Maumee River, St. Marys River, Monongahela River, West Fork River, Beaver River, Pymatuning Creek, Mahoning River, Little Kanawha River, Big Sandy River, Levisa Fork, Scioto River, Olentangy River, Whetstone Creek, Big Walnut Creek, Alum Creek, Russell Creek, Barren River, Drakes Creek, West Fork Drakes Creek, Middle Fork Vermillion River, Salt Fork Vermillion River, White River, East Fork White River, Driftwood River, Big Blue River, Flatrock River, West Fork White River, Rockcastle River, Big South Fork, Beaver Creek, Caney Fork, Stones River, West Fork Stones River, Harpeth River, Holston River, Clinch River, Sequatchie River, Larkin Fork, Flint River, North Fork White River, Verdigris River, Fall River, Blue River, Mountain Fork Little River). In some streams the only records known represent archeological specimens (e.g., Little Pigeon River, Little Tennessee River, Yazoo River). The compilation of distributional information herein abundantly indicates a severe reduction in range of the rabbitsfoot over the past 40 years. Based on historical and current data, the rabbitsfoot is declining rangewide and is now extant only in 46 of 137 streams of historical occurrence, representing a 66% decline. Further, in the streams where it is extant, populations with few exceptions are highly fragmented and restricted to short reaches. Any historical occurrences in Georgia are now believed extirpated (J. Wisniewski, GA NHP, pers. comm., January 2007). The rabbitsfoot is believed extirpated from Georgia and West Virginia, while its continued existence in several other states (e.g., Alabama, Kansas, Louisiana, Mississippi, Missouri) is extremely perilous (Butler, 2005). Quadrula cylindrica strigillata intergrades with Quadrula cylindrica cylindrica in the Clinch River in Scott County, Virginia. Realistically, much more than 66% of the species' historically available habitat no longer supports populations. Total range reduction and overall population loss for the rabbitsfoot realistically approaches--if not exceeds--90% (Butler, 2005).

Sources and Credits

1. (c) Tim Lane, some rights reserved (CC BY-NC-ND), https://www.flickr.com/photos/119210184@N05/12941044704/
2. (c) Femorale, some rights reserved (CC BY-NC), http://www.femorale.com/shellphotos/detail.asp?species=Quadrula%20cylindrica%20cylindrica%20(Say,%201817)
3. (c) NatureServe, some rights reserved (CC BY-NC), http://eol.org/data_objects/28870896
4. (c) NatureServe, some rights reserved (CC BY-NC), http://eol.org/data_objects/28870903
5. (c) International Union for Conservation of Nature and Natural Resources, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/34693193
6. (c) NatureServe, some rights reserved (CC BY-NC), http://eol.org/data_objects/28870889
7. (c) NatureServe, some rights reserved (CC BY-NC), http://eol.org/data_objects/28870894
8. (c) NatureServe, some rights reserved (CC BY-NC), http://eol.org/data_objects/28870893

More Info

• iNat taxon page
• Animal Diversity Web
• Biodiversity Heritage Library
• BOLD Systems BIN search
• Global Biodiversity Information Facility (GBIF)
• SeaLifeBase
• World Register of Marine Species

iNat Map