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The Sipsey River, Alabama: A Crayfish Diversity “Hotspot”?
Jonathan D. Hopper, Alexander D. Huryn, and Guenter A. Schusters

Southeastern Naturalist, Volume 11, Issue 3 (2012): 405–414

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2012 SOUTHEASTERN NATURALIST 11(3):405–414 The Sipsey River, Alabama: A Crayfish Diversity “Hotspot”? Jonathan D. Hopper1, *, Alexander D. Huryn1, and Guenter A. Schuster2 Abstract - The southeastern United States contains ca. 250 species of crayfish. Of these, 85 are historically known from Alabama. Previous studies have shown that the Sipsey River drainage in western Alabama is a diversity “hotspot” for freshwater mussels (42 spp.) and fishes (102 spp.). This is attributed to diverse geologic features, an intact floodplain, lack of impoundments, and lack of urban centers. Intensive sampling of the Sipsey River drainage over a 2-year period resulted in a collection of 294 crayfish representing 12 species. Three of these species, Cambarus ludovicianus, Orconectes chickasawae, and Procambarus vioscai paynei are of conservation concern. Our results indicate that the Sipsey River harbors a greater richness of crayfish species per area than other drainages surveyed to date in Alabama. Introduction The southeastern United States harbors about two-thirds of the crayfish species found in North America (Taylor et al. 2007). Despite this, the crayfish of this region remain understudied (Heath et al. 2010, Schuster et al. 2008). Of 250 species reported from the southeast, 85 (34%) crayfish species are known from Alabama (Taylor and Schuster 2007, Taylor et al. 2007). This is a greater taxonomic richness than found in the adjacent states of Mississippi (78 spp.; Fitzpatrick 2002), Tennessee (77 spp.; Bouchard 1972), Georgia (68 spp.; Hobbs 1981), and Florida (57 spp.; Franz and Franz 1990). Gaining knowledge of crayfish distribution and ecology is important due to their relatively high level of imperilment—only 52% of American species are listed as stable (Taylor et al. 2007, Wilcove et al. 1998). Their imperilment is believed to be due primarily to widespread damming of rivers and urbanization, which has had negative consequences for other major groups of freshwater fauna such as mussels (Lindemayer et al. 2009), snails (Seddon 2000), and fishes (Boschung and Mayden 2004). For example, 65–75% of all bivalve taxa native to the United States are either in decline or extinct (Bogan 2008, Lindemayer et al. 2009, Williams et al. 2008). The Sipsey River in western Alabama is one of 42 rivers in the continental United States identified as both high quality and worthy of federal protection according to the Nationwide Rivers Inventory (Benke 1990). Many rivers in the United States have been dammed, diverted, channelized, or otherwise urbanized. The Sipsey River, however, remains relatively intact. With no impoundments, it is the second longest free-flowing river in Alabama. Furthermore, it flows through a variety of 1Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL 35487. 2Department of Biological Sciences, Eastern Kentucky University, Richmond, KY 40475. *Corresponding author - 406 Southeastern Naturalist Vol. 11, No. 3 geological provinces and ecoregions in a distinctively narrow drainage that terminates in an intact bottomland hardwood floodplain. Factors such as these underlie the diverse assemblages of flora and fauna that occur here. For example, 42 species of freshwater mussels have been documented from mainstem habitats of the Sipsey River (McCullagh et al. 2003), and 102 species of fishes have been recorded from the greater drainage (ADCNR 2012, Boschung and Mayden 2004). Although the fish and mussel diversity of the Sipsey River drainage have been relatively well surveyed, no systematic surveys of crayfishes have been conducted. Our study goals were to 1) determine what crayfish species were present, 2) document the distributions of these species, and 3) compare the numbers of species per drainage area to similar crayfish studies conducted elsewhere. Methods Study sites We sampled 20 locations within nine tributaries and along the mainstem of the Sipsey River in an attempt to represent the topographical and ecological diversity of the entire drainage. These sampling locations included first-, second-, and third-order tributaries and the mainstem (Fig. 1). The 148-km mainstem of the Sipsey River traverses both the Southwestern Appalachian Plateau and Southeastern Plains ecoregions, which are further subdivided into four sub-regions that are each geologically distinct—the Dissected Plateau, Shale Hills, Fall Line Hills, and the Southeastern Floodplain (Griffith et al. 2001, Sapp and Emplaincort 1975). The most northern headwaters of the Sipsey River are found in the Dissected Plateau sub-region. Streams sampled in this portion of the drainage included the New River (Site 1), Little New River (Site 2), and Thompson Branch (Site 3) (Fig. 1). These densely shaded streams flow over bedrock or sand substrata. Habitats sampled in the Shale Hills included Boxes Creek (Sites 4, 5), which has a bed composed of sand and silt. Streams in this sub-region are often affected by coal-mining activities. Habitats sampled in the Fall Line Hills sub-region included a drainage ditch near the town of Fayette (Site 6), Davis Creek (Sites 7, 8), several mainstem locations near bridges (Sites 9, 10, 11), the Sipsey River Swamp Recreation Area (Site 12), and Malone Mill Creek (Sites 13,14). Fall Line Hills streams typically have low gradients, substrata composed of sand and silt, and dense forest canopies. The Southeastern Floodplain sub-region contains the lower reaches of the Sipsey River and its confluence with the Tombigbee River. This region has a relatively flat, uniform topography with numerous disconnected pools and oxbow lakes and extensive tracts of swamp forest dominated by Nyssa aquatica L. (Tupelo) and Taxodium distichum (L.) Rich (Cypress). Here the mainstem of the Sipsey River and its tributaries have low gradients and compacted silt substrata, although outcrops of slate occur in some of the smaller streams. Sampling locations in the Southeastern Floodplain sub-region included two mainstem habitats near bridges (Sites 17, 19), Taylor Creek (Sites 15, 16), Brush Creek (Site 18), and Hughes Creek (Site 20). 2012 J.D. Hopper, A.D. Huryn, and G.A. Schuster 407 Crayfish sampling and identification Crayfishes of in-stream habitats were sampled from November 2007 to July 2009 using baited minnow traps (Edwards et al. 2009) with 3.8-cm openings. Sampling at a given location usually consisted of deploying 6–12 traps for 3–7 Figure 1. Map showing 20 crayfish sampling locations within the Sipsey River drainage in west-central Alabama. 1 = New River, 2 = Little New River, 3 = Thompson Branch, 4 = Boxes Creek (1st order), 5 = Boxes Creek (2nd order), 6 = ditch along CR 53 near Fayette, 7 = Davis Creek (1st order), 8 = Davis Creek (2nd order), 9 = Sipsey River at CR 12, 10 = Sipsey River at Brownville Pike, 11 = Sipsey River at CR 140, 12 = Sipsey River at Sipsey River Swamp Recreation Area, 13 = Malone Mill Creek (1st order), 14 = Malone Mill Creek (3rd order), 15 = Taylor Creek (3rd order), 16 = Taylor Creek (1st order), 17 = Sipsey River at CR 156, 18 = Brush Creek, 19 = Sipsey River at CR 181, 20 = Hughes Creek. 408 Southeastern Naturalist Vol. 11, No. 3 days. On some occasions, traps were deployed for as long as 14 days due to flooding. Locations were sampled 1 (Site 3) to 12 (Site 12) times during the study (mean number of sampling events per location = 5). Traps were deployed a minimum distance of 20 m upstream and downstream of bridges in an attempt to decrease potential bridge effects. Trapping was supplemented with sampling using D-frame nets and seines. Burrowing crayfish were sampled by hand and/ or trowel excavation. When excavation was not possible, a covered bucket with a funnel inserted in its bottom was placed over a burrow opening to trap emerging crayfish (Hopper and Huryn 2012). We were disinclined to make estimates of catch per unit effort due to our use of several different sampling approaches. Once captured, crayfish were returned to the laboratory and frozen. Specimens were later identified to species using Hobbs (1989), and total carapace length (TCL: length in mm from the tip of the rostrum to the posterior margin of the areola) was measured. Form I males where used for identification when available, otherwise species identifications were attempted using Form II males or females (Schuster and Taylor 2009). Voucher specimens, preserved in 70% ethanol, were deposited in the collections of the University of Alabama Decapoda Collection (UADC). The common names of crayfish species reported herein follow Taylor et al. (2007), and information concerning their conservation status follows Smith et al. (2011). Differences in crayfish species richness found in this study and previous studies of other drainages in Alabama (Heath et al. 2010, McGregor et al. 1999, Ratcliffe and DeVries 2004, Schuster et al. 2008) were assessed by comparing area-weighted species richness, which was calculated by dividing the number of species of crayfish collected by the total drainage area of the basin. Drainage area used was either taken from the cited reference (Heath et al. 2010, Ratcliffe and DeVries 2004) or obtained from Benke and Cushing (2005) or state government internet resources (GDNR 1998). Results A total of 294 individuals representing four genera and 12 species of crayfish were collected from the Sipsey River drainage during this study (Table 1). The majority of locations (12 locations) yielded 2–3 species of crayfish. Mainstem habitats at the Sipsey River Swamp Recreation Area (Site 12; Fig. 1, Table 1) contained the greatest species richness (6 species). Cambarus striatus Hay (Ambiguous Crayfish), collected at 12 locations, was the most widespread species. Cambarus diogenes Girard (Devil Crayfish), Procambarus acutus Girard (White River Crawfish), and Orconectes perfectus Walls (Complete Crayfish) were also relatively widespread, occurring at six or more locations. Fallicambarus fodiens Cottle (Digger Crayfish) , Orconectes chickasawae Cooper and Hobbs (Complete Crayfish) and O. sp., a provisional new species (G.A. Schuster and C.A. Taylor, Illinois Natural History Survey, Champaign, IL, unpubl. data), however, were collected only at single locations. Procambarus acutus (50 individuals) and Cambarus striatus (48 individuals) yielded the greatest number of specimens 2012 J.D. Hopper, A.D. Huryn, and G.A. Schuster 409 collected (33% of all specimens). Orconectes perfectus (38 individuals), Cambarus diogenes (37 individuals) and C. latimanus LeConte (Variable Crayfish) (35 individuals) contributed an additional 37% of the total number of crayfish collected. The Sipsey River drainage yields an area-weighted crayfish species richness of 0.59 species/100 km2 (Table 2). Annotated species list Cambarus (Depressicambarus) latimanus LeConte (Variable Crayfish) was found at two locations (Table 1, Fig. 1). The TCL of the 35 specimens collected ranged from 30 to 110 mm (mean = 53 mm). Biological notes: Juveniles were found in secondary burrows near the stream channel margin (shallow burrows). Conservation status: Currently stable, P4. Cambarus (Depressicambarus) striatus Hay (Ambiguous Crayfish) was found at eight locations (Table 1, Fig. 1). The TCL of the 48 specimens collected ranged from 30–57 mm (mean = 41 mm). Biological notes: Juveniles were usually found in shallow secondary burrows near the stream channel margins. Cambarus Table 1. Crayfishes occurring in the Sipsey River drainage in west-central Alabama. Species indicated by an asterisk (*) were historically collected prior to this study (G.A. Schuster and C.A. Taylor, unpubl. museum records). Columns indicated by sampling location (Fig. 1.) contain the total numbers of specimens of each species collected from November 2007 through April 2009. Sampling location Species 1 2 3 4 5 6 7 8 9 10 Cambarus diogenes* - - - - 3 1 - - 1 - C. latimanus - - - - - - - - - - C. ludovicianus - 1 - - - 3 - - - - C. striatus* 18 2 1 1 1 - 3 - - 3 Fallicambarus fodiens - - - - - - - - - - Orconectes chickasawae* - - - - - - - - - - O. perfectus* 22 1 1 7 3 - 4 - - - O. validus* - - - - - - - - - - O. n. sp.* 2 - - - - - - - - - Procambarus acutus* - - - - - - - 1 - 15 P. clarkii* - - - - - - - - - 18 P. vioscai paynei* - - - - - - - - - - Species 11 12 13 14 15 16 17 18 19 20 Cambarus diogenes* 14 6 - 10 - 2 - - - - C. latimanus 14 17 - - 1 - 3 - - - C. ludovicianus - - - - - - - - - - C. striatus* - 1 - - - 2 14 - 1 1 Fallicambarus fodiens - - - 2 - - - - - - Orconectes chickasawae* - - - - - - - - - 18 O. perfectus* - - - - - - - - - - O. validus* 5 1 - - - - - - - - O. n. sp. - - - - - - - - - - Procambarus acutus* - 3 3 1 - 9 18 - - - P. clarkii* 5 4 - - - - - - - - P. vioscai paynei* - - - - - - - 6 - 21 410 Southeastern Naturalist Vol. 11, No. 3 striatus appears to be primarily nocturnal, as few were captured during the day. Most were captured at night in minnow traps. Conservation status: Currently stable, P5. Cambarus (Lacunicambarus) diogenes Girard (Devil Crayfish) was found at six locations (Table 1, Fig. 1). The TCL of the 37 specimens collected ranged from 43–56 mm (mean = 50 mm). Biological notes: This species was typically found in burrows, with most captured at Taylor Creek and Malone Mill Creek. Conservation status: Currently stable, P5. Cambarus (Lacunicambarus) ludovicianus Faxon (Painted Devil Crayfish) was found at two locations (Table 1, Fig. 1). The TCL of the four specimens collected ranged from 36–46 mm (mean = 41 mm). Biological notes: Prior to this study, the range of C. ludovicianus in Alabama was believed to be restricted to the Mobile Bay area (Schuster et al. 2008). We collected C. ludovicianus at two locations in the northern tributaries of the Sipsey River. One specimen was excavated from a burrow along the Little New River. Three others were excavated from burrows along a 5-m long drainage ditch east of Fayette (Site 6, Fig. 1). Conservation status: Currently stable, P3. Cambarus ludovicianus is of moderate conservation concern in Alabama (ACWCS 2005). Fallicambarus (Creaserinus) fodiens Cottle (Digger Crayfish) was found only at Malone Mill Creek (Table 1, Fig. 1). The TCL of the two specimens collected was 14 mm (mean = 14 mm). Biological notes: F. fodiens, Cambarus diogenes, and C. ludovicianus were the only primary burrowers documented from the Sipsey River drainage. Conservation status: Currently stable, P5. Orconectes (Trisellescens) validus Faxon (Powerful Crayfish) was found only in mainstem habitats at the Sipsey River Swamp Recreation Areas and near the CR 140 bridge (Table 1, Fig. 1). The TCL of the six specimens collected ranged from 22–25 mm (mean = 24 mm). Biological notes: Like many other species of the subgenus Trisellescens, O. validus prefers leaf cover along the margins of streams (G.A. Schuster, pers. observ.). Conservation status: Currently stable, P5. Orconectes (Trisellescens) chickasawae Cooper and Hobbs (Chickasaw Crayfish) was found only at Hughes Creek (Table 1, Fig. 1). The TCL of the 18 specimens collected ranged from 26–28 mm (mean = 27 mm). Biological notes: Orconectes chickasawae belongs to a group of species (subgenus Trisellescens) that is currently undergoing taxonomic revision (G.A. Schuster and C.A. Taylor, unpubl. data). Conservation status: Currently stable, P3. Orconectes chickasawae is of high conservation concern in Alabama (ACWCS 2005). Orconectes (Trisellescens) n. sp. (no common name) was found only at the New River near Natural Bridge (Table 1, Fig. 1). This species is currently undescribed (G.A. Schuster and C.A. Taylor 2009, unpubl. data). The TCL of the two specimens collected ranged from 18 to 21 mm. Biological notes: Specimens were found in leaf matter along a stream margin. Conservation status: n.a. Orconectes (Hespericambarus) perfectus Walls (Complete Crayfish) was found at four locations (Table 1, Fig. 1). The TCL of the 38 specimens collected ranged from 17–39 mm (mean = 32 mm). Biological notes: This species is 2012 J.D. Hopper, A.D. Huryn, and G.A. Schuster 411 particularly abundant at the New River near Natural Bridge where a population of Cambarus striatus was also found. Orconectes perfectus was readily collected during the day, whereas Cambarus striatus was only captured by overnight minnow trapping. These two species may demonstrate a form of day/night activity partitioning. Conservation status: Currently stable, P5. Procambarus (Scapulicambarus) clarkii Girard (Red Swamp Crayfish) was found at three locations (Table 1, Fig. 1). The TCL of the 27 specimens collected ranged from 32–41 mm (mean = 36 mm). Biological notes: The first records of P. clarkii for the Sipsey River drainage were from the vicinity of Malone Mill Creek in 2007 (Smith et al. 2011). The first specimens found in this study were collected in January 2008 at the County Road (CR) 140 bridge (Site 11). P. clarkii was subsequently found from the Sipsey River Swamp Recreation Area north to the Brownville Pike sampling area. Conservation status: Currently stable, P5. Procambarus (Pennides) vioscai paynei Fitzpatrick (Payne’s Creek Crayfish) was found at two locations (Table 1, Fig. 1). The TCL of the 27 specimens collected ranged from 30–34 mm (mean = 32 mm). Conservation status: Currently stable, P3. P. vioscai paynei is of moderate conservation concern in Alabama (ACWCS 2005). Procambarus (Ortmannicus) acutus acutus Girard (White River Crayfish) was found at five locations (Table 1, Fig. 1). The TCL of the 50 specimens collected ranged from 29–54 mm (mean = 42 mm). Biological notes: Promcambarus acutus is abundant in floodplain swamps, including those highly modified by human activities such as the clear-cut floodplain swamp downstream of the Brownville Pike crossing. Conservation status: Currently stable, P5. Discussion Twelve species of crayfish representing four genera have been reported from the Sipsey River drainage. The discovery of two of these species in the Sipsey River drainage represents significant range extensions. The occurrence of Cambarus ludovicianus in the Little New River is the first record north of the Mobile Bay region, and the capture of Orconectes chickasawae at Hughes Creek is the first record published for this species in Alabama. In addition, Cambarus Table 2. Summary of data from crayfish surveys conducted in Alabama. Source = citation, # locations = number of sampling locations, Days/location = range of cumulative days traps were deployed at each location during study, ES = electro-shocking, D = dip net, S = seine, K = kick net, T = trap, R = number of species reported, Area = km2 of drainage sampled, R/100 km2 = areaweighted species richness. Source # locations Days/location Method R Area (km2) R/100 km2 Heath et al. 2010 50 1 ES/D 10 10,937 0.09 McGregor et al. 1999 56 less than 1 S 10 43,173 0.02 Ratcliffe and DeVries 2004 39 1 T/K/S 6 6373 0.09 This study 25 3–7* T/K/S 12 2044 0.59 *Traps were deployed for 3–7 days during a single sampling event. The number of sampling events varied from 1 to 12 depending upon location. 412 Southeastern Naturalist Vol. 11, No. 3 ludovicianus, Orconectes chickasawae, and Procambarus vioscai paynei are considered species of conservation concern (ADCNR 2005). These records together highlight the significant conservation value of the Sipsey River drainage. The Sipsey River drainage yields an area-weighted crayfish species richness (0.59 species/100 km2) that is substantially greater than the statewide richness of 0.13 species/100 km2 and levels of richness calculated for similar surveys in Alabama (Table 2). For example, a survey of the crayfish of the Lower Tombigbee and Alabama drainages yielded an area-weighted species richness of 0.02 species/100 km2 (Table 2; McGregor et al. 1996). Similarly, a survey of the Tallapoosa River in eastern Alabama, a drainage more than twice the size of the Sipsey River, yielded 0.09 species/100 km2 (Table 2; Ratcliffe and DeVris 2004), and a survey of the southeastern portion of the state encompassing an area about five times larger than the Sipsey River drainage yielded 0.09 crayfish species/100 km2 (Table 2; Heath et al. 2010). Finally, data from Schuster et al. (2008) indicate levels of area-weighted crayfish species richness of 0.25, 0.20, and 0.07 species/100 km2 for the Cahaba, Escambia, and Choctawhatchee drainages, respectively. The relatively large number of crayfish species found in our study could be attributed to more intensive sampling compared with surveys of larger drainages (Table 2). Consequently, the comparison of the results of our study with those of others should be treated with caution. Nevertheless, the Sipsey River drainage clearly contains a rich crayfish fauna, particularly when compared with the statewide species richness of 0.13 species/100 km2, and should be considered a “hotspot” for crayfish diversity. Acknowledgments We wish to thank the Alabama Geological Survey, particularly J. Brett Smith, for field assistance . 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