2013 SOUTHEASTERN NATURALIST 12(2):267–282 Historical vs. Current Biological Assemblages in the Little Choctawhatchee Watershed, Southeastern AL Jonathan M. Miller1 and Paul M. Stewart1,* Abstract - The Little Choctawhatchee River watershed is currently affected by effluents from wastewater treatment plants and may be subject to impoundment as a water supply reservoir. We used historical data from the literature and the results of recent surveys (2006–2008) to assess past and current patterns of the diversity of mussels, crayfishes, and fishes throughout the river basin in order to gain information about the past and potential future effects of degraded water and habitat quality to the fauna of this region. Our results suggest that mussel assemblages have declined dramatically from historical levels, with only three of the eleven historically recorded species found. Several statelisted mussel species and candidates for federal protection formerly present are now believed extirpated from the watershed. Fish and crayfish collections during 2006–2008 were more diverse (52 and 6 species) than historical records indicated (39 and 3 species). This increased diversity was probably due to a more concentrated sampling effort in the current study than in the past. Future impoundment may cause further and possibly drastic changes to the remaining freshwater faunal diversity. Introduction Alabama is second in the number of fish species (Boschung and Mayden 2004) and first in number of crayfish (Taylor and Schuster 2007) and mussel species (Williams et al. 2008) of any state in the US. Widespread changes in the environment are causing declines in populations of many of these species. The ability to sustain stream biodiversity is becoming more difficult with increasing US water needs and withdrawals, which reached over 1500 billion liters per day in 2000 (USGS 2008). While dams are one of the most harmful human practices affecting aquatic biodiversity, reservoirs on many medium and large rivers are a necessity for water storage. However, sufficient biological data allowing adequate assessments of changes in biodiversity between pre- and post-dam construction are rarely available. One of the few free-flowing river systems in the southeastern United States is the Choctawhatchee River in Alabama and Florida. The Choctawhatchee, Pea, and Yellow Rivers Watershed Management Authority (CPYRWMA) has started the permitting processes for the placement of a water supply reservoir on the Little Choctawhatchee River (LCR), a tributary to the Choctawhatchee River. Baseline information on mussel, crayfish, and fish assemblages is especially important so that the future status and an estimation of degradation can be made. Inferences from past data indicate that stream water quality is already degraded. This degradation has been primarily attributed to wastewater treatment plants 1Department of Biological and Environmental Sciences, Troy University, Troy, AL, 36082. *Corresponding author - mstewart@troy.edu. 268 Southeastern Naturalist Vol. 12, No. 2 (WWTPs), urbanization of headwater catchments originating in the city of Dothan, AL, and a high proportion of agricultural land-use (Miller 2009 ). One of the major disturbances to the LCR has been the Beaver Creek Wastewater Treatment Plant (WWTP) discharge. This WWTP has recently been cited by the Circuit Court of Houston County, AL, for its failure to meet and comply with permit requirements and the Alabama Water Pollution Control Act (Circuit Court of Houston County 2008). Since this time, the EPA has begun investigating both WWTPs in Dothan, and the city is at risk of potential fines related to overflows of the Beaver Creek WWTP (Griffin 2011). Poorly managed WWTPs significantly alter limnological conditions, and increased nutrient loads can be detected several kilometers downstream of the source (Haggard e t al. 2005). This study focused on mussel, crayfish, and fish assemblages of t he LCR and tributaries prior to impoundment of the LCR near Dothan, AL. The objectives of this study were to: 1) sample mussel, crayfish, and fish assemblages of the LCR and compare these with historical data; and 2) speculate on the probable fate of these assemblages if the proposed reservoir is built. Methods Study area The LCR is a tributary to the Choctawhatchee River in southeast Alabama (Fig. 1). The LCR originates near Dothan, AL and flows west until converging with the Choctawhatchee River about 5 km southeast of Daleville, AL (encompassed in Houston, Dale, and Geneva counties). The LCR watershed drains about 430 km2, and the river is located about 11 km directly south of the confluence of the East and West Forks of the Choctawhatchee River. The LCR watershed has experienced significant alterations through various land-use practices, primarily urbanization in and around the city of Dothan. Urban development and agriculture are currently the dominate land-use (>60%) within the LCR watershed (ACES 2008). Site selection and data collection Twelve sites were sampled for fishes and crayfishes, and 16 were sampled for mussels (Table 1). Sites were selected according to accessibility and available historical data. All suitable habitats within the reaches were qualitatively sampled one time for mussels by tactile search (2–4 man-hours per site, for a total of over 40 man-hours for the entire survey). Crayfish and fish were sampled using a pulsed DC Smith-Root® backpack electroshocker in wadeable streams and a Smith-Root® boat-mounted gas-powered pulsator electroshocker in nonwadeable streams. Fishes and crayfishes were retained in different containers during sampling to prevent predation. Sampling began immediately downstream of bridge crossings and included degraded habitats (riprap, scour holes, etc.) near bridges and then proceeded upstream. The length of reaches sampled was about 35 times the mean stream width but no less than 150 m and no more than 300 m (modified from Morris et al. 2007). Site LCR6 encompassed an area beginning about 300 m downstream of the bridge due to an available input location and a channel wide enough for aquatic sampling via boat electrofishing. If burrows 2013 J.M. Miller and P.M. Stewart 269 Figure 1. Twelve stream sampling sites on the Little Choctawhatchee River and tributaries near Dothan in southeast Alabama, along with two additional mussel sites and two sections (LCR2-LCR3, LCR5-LCR6) of the river sampled for mussels (shaded area on stream). Table 1. Site number, name, latitude, longitude, and organisms sampled (M = mussels, F = fish, C = crayfish), for sites in the Little Choctawhatchee River watershed in southeast Alabama. Organisms Site No. River/tributary Latitude Longitude sampled LCR1 Little Choctawhatchee River 31º15'44"N 085º40'07"W M, F, C LCR2 Little Choctawhatchee River 31º16'23"N 085º38'52"W M, F, C LCR3 Little Choctawhatchee River 31º16'23"N 085º37'11"W M, F, C LCR4 Little Choctawhatchee River 31º15'49"N 085º34'13"W M, F, C LCR5 Little Choctawhatchee River 31º15'08"N 085º31'47"W M, F, C LCR6 Little Choctawhatchee River 31º14'45"N 085º28'58"W M, F, C 7 Unnamed Tributary 31º16'23"N 085º33'53"W M, F, C 8 Bear Creek 31º14'17"N 085º32'22"W M, F, C 9 Newton Creek 31º14'20"N 085º30'09"W M, F, C 10 Harrison Mill Creek 31º17'23"N 085º29'17"W M, F, C 11 Beaver Creek 31º12'54"N 085º26'06"W M, F, C 12 Quail Creek/Little Choctawhatchee River 31º17'13"N 085º25'09"W M, F, C 13 Panther Creek 31º14'32"N 085º35'03"W M 14 Quail Creek/Little Choctawhatchee River 31º16'49"N 085º25'32"W M 15 Little Choctawhatchee River 31º16'23"N 085º37'11"W M (between sites LCR2 and to to LCR3) 31º16'23"N 085º38'52"W 16 Little Choctawhatchee River 31º14'45"N 085º28'58"W M (between sites LCR5 and to to LCR6) 31º15'08"N 085º31'47"W 270 Southeastern Naturalist Vol. 12, No. 2 were present, burrowing crayfishes were collected along the stream banks by hand excavation for 1–3 man-hours at a site from May to June 2008. All species were identified using appropriate taxonomic literature (mussels: Williams et al. 2008; crayfishes: Hobbs 1942, 1989; Taylor and Schuster 2004; fishes: Boschung and Mayden 2004, Mettee et al. 1996). Any anomalies such as deformities, eroded fins, lesions, and tumors (DELTs) of fishes were noted. Species not easily identified in the field were preserved (fishes in 10% formalin, crayfishes and mussels in 70% alcohol) and brought to the laboratory for verification with standard taxonomic keys and confirmations by professional taxonomists. Reference collections were curated in the Aquatic Laboratory at Troy University. All biological data collected in the study were compared to historical data gathered from the literature (Blalock-Herod et al. 2005, Boschung and Mayden 2004, Heath 2008, Heath et al. 2010, Mettee et al. 1996, Pilarczyk 2005, Pilarczyk et al. 2006, Williams et al. 2008). Results Mussels One hundred forty-one live mussel specimens were collected in this study (Table 2). Species found in this study included Villosa lienosa (n = 124), Toxolasma sp. (n = 12), Uniomerus tetralasmus (n = 4), and Villosa vibex (n = 1). Uniomerus tetralasmus was the only species added to the list of those known from the LCR drainage. No mussels were collected at 10 of the 16 sites. Only one species was found at two sites, two species were found at three sites, and three species were found at one site. Historical collections in the LCR watershed included 11 species (Table 2; Blalock-Herod et al. 2005, Williams et al. 2008). Crayfishes Six species totaling 1191 crayfishes were collected during this study (Table 3). The majority (1115, consisting of 32 primary and secondary burrowers and 1083 tertiary burrowers) were collected within the stream by electroshocking over the six sampling events, whereas 76 primary burrowers were collected in June 2008 by hand excavation. Procambarus suttkusi was the only species found at all 12 sites. Cambarus polychromatus was found during burrow excavation only, and Cambarus diogenes was found both during excavation and electrofishing; the remaining species were collected during electrofishing. Historical collections in the LCR watershed included 3 crayfish species (Table 3; Heath 2008). Procambarus spiculifer, Cambarus latimanus, and C. diogenes were collected during 2006–2008 but had never before been reported from the LCR drainage. Fishes A total of 14,453 fishes were collected from 12 sites (six visits to each site). Fifty-two species, representing 16 families, were collected (Table 4). Three hybrid sunfish and at least 19 (0.13%) DELTs were found during fish collections. Cyprinidae comprised 57% of the individuals collected, Centrarchidae 20.5%, 2013 J.M. Miller and P.M. Stewart 271 Table 2. Historical (Blalock-Herod et al. 2005, Williams et al. 2008) and current mussel species collected by site from the Little Choctawhatchee River watershed from May 2008 to November 2008. Current study Historical LCR Species Common name data 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Total Elliptio arctata (Conrad) Delicate Spike X Elliptio pullata (Lea) Gulf Spike X Hamiota australis (Simpson) Southern Sandshell X Fusconaia burkei (Walker) Tapered Pigtoe X Lampsilis straminea (Conrad) Southern Fatmucket X Medionidus acutissimus (Lea) Alabama Moccasinshell X Pleurobema strodeanum (Wright) Fuzzy Pigtoe X Quadrula succissa (Lea) Purple Pigtoe X Toxolasma sp. Gulf Lilliput X 2 4 6 12 Uniomerus tetralasmus (Say) Pondhorn 4 4 Villosa lienosa (Conrad) Little Spectacle-case X 28 61 3 27 2 3 124 Villosa vibex (Conrad) Southern Rainbow X 1 1 Table 3. Historical (Heath 2008) and current crayfish species collected by site from the Little Choctawhatchee River watershed from December 2006 to June 2008. Current study Historical Species Common name data LCR1 LCR2 LCR3 LCR4 LCR5 LCR6 7 8 9 10 11 12 Total Cambarus diogenes Girard Devil Crayfish 2 2 5 23 8 40 Cambarus latimanus LeConte Variable Crayfish 1 9 1 9 Cambarus polychromatus Thoma Paintedhand Mudbug X 1 8 8 9 10 8 5 6 6 5 66 Procambarus okaloosae (Hobbs) Okaloosa Crayfish X 1 3 4 8 Procambarus spiculifer (LeConte) White Tubercled Crayfish 2 2 Procambarus suttkusi (Hobbs) Choctawhatchee Crayfish X 150 52 84 141 37 97 243 11 67 153 11 18 1064 272 Southeastern Naturalist Vol. 12, No. 2 and Percidae 7%. The greatest number of fishes collected (n = 1150) was at Beaver Creek in March 2008, with the second highest number of individuals collected (n = 1088) at this site the previous November. Table 4. Fishes collected by site from the Little Choctawhatchee River watershed from December 2006 to June 2008. Site LCR Species 1 2 3 4 5 6 7 8 9 10 11 12 Ichthyomyzon gagei 1 2 3 1 2 3 5 Lepisosteus oculatus 2 8 2 18 15 4 Lepisosteus osseus 2 9 Amia calva 1 4 4 5 Anguilla rostrata 1 1 1 3 5 1 Cyprinella venusta 243 479 69 102 132 69 205 1 32 1 5 Hybopsis sp. cf. winchelliA 80 335 82 35 76 12 10 34 13 464 73 Lythrurus atrapiculus 1 1 15 10 75 54 506 178 Notemigonus crysoleucas 24 9 Notropis amplamala 15 112 29 30 18 1 446 2 275 47 22 Notropis longirostris 158 265 36 27 9 115 1 1 Notropis maculatus 2 Notropis texanus 9 41 13 28 77 58 192 29 44 225 1114 229 Opsopoeodus emiliae 3 Pteronotropis merlini 2 2 2 26 3 23 285 6 297 11 Semotilus thoreauianus 360 1 123 Erimyzon sucetta 1 25 1 1 15 1 5 21 13 Minytrema melanops 2 15 18 56 18 12 19 41 Moxostoma poecilurum 18 29 7 26 37 15 27 11 13 1 1 Ameiurus natalis 2 1 6 10 1 1 8 5 Ameiurus nebulosus 1 1 1 1 Ictalurus punctatus 3 1 1 1 Noturus leptacanthus 40 17 26 22 3 6 16 1 2 35 5 Esox americanus 3 2 4 1 6 2 12 3 10 3 3 Esox niger 1 2 Aphredoderus sayanus 16 3 11 56 42 61 27 14 22 52 28 14 Labidesthes sicculus 1 1 8 21 11 Fundulus olivaceus 29 17 15 48 4 4 12 19 12 42 Gambusia holbrooki 2 1 13 4 1 65 27 10 49 613 38 Ambloplites ariommus 12 4 11 4 5 7 1 Centrarchus macropterus 1 1 Lepomis auritus 3 22 22 33 20 12 11 2 2 68 20 Lepomis cyanellus 17 1 8 5 3 12 10 3 20 31 Lepomis gulosus 8 1 13 7 21 4 40 10 13 17 Lepomis macrochirus 24 41 8 49 64 59 17 51 26 1 78 46 Lepomis marginatus 3 2 3 4 1 1 7 2 1 13 Lepomis megalotis 44 27 26 74 92 97 8 26 61 8 378 37 Lepomis microlophus 4 4 5 3 29 2 Lepomis miniatus 37 13 10 57 55 77 129 114 81 26 115 84 Micropterus punctulatus 31 33 8 4 7 2 1 1 4 1 Micropterus salmoides 2 2 3 6 25 13 19 21 3 36 2 Pomoxis annularis 1 1 Pomoxis nigromaculatus 3 Ammocrypta bifascia 6 1 2013 J.M. Miller and P.M. Stewart 273 The mean fish taxa richness per site/collection date across the watershed was 18.4 (SE = 0.51). The sites producing the most species cumulatively over all the sampling events (six) were LCR5 with 41 species and LCR4 and Newton Creek, both with 36 species. The unnamed tributary (site 7) produced the fewest species cumulatively over all the sampling events with 23 species, followed by Beaver Creek with 25 species. The five most abundant fish species collected over the entire study were Notropis texanus (n = 2059), Cyprinella venusta (n = 1338), Hybopsis sp. cf. winchelli (n = 1214), Notropis amplamala (n = 997), and Lepomis megalotis (n = 878), which together accounted for 44.9% of the total catch. Species rarely found in this study were Notropis maculatus (n = 2, Bear Creek), Pomoxis annularis (n = 2, Newton Creek and LCR6), Centrarchus macropterus (n = 2, LCR2 and LCR3), Trinectes maculatus (n = 2, LCR1 and LCR2), Opsopoeodus emiliae (n = 3, Bear Creek), Percina nigromaculatus (n = 3, LCR5), and Esox niger (n = 3, LCR5 and Newton Creek). Five species were found at all sites (N. texanus, Aphredoderus sayanus, Lepomis macrochirus, L. megalotis, and L. miniatus), while N. maculatus and O. emiliae were only found at Bear Creek. Thirty-four of the 39 species found in the historical records were collected in the current study, which increased species richness in the watershed by 18 species (Table 5). Table 4, continued. Site LCR Species 1 2 3 4 5 6 7 8 9 10 11 12 Etheostoma colorosum 1 1 4 12 2 3 2 2 Etheostoma davisoni 3 4 3 3 5 2 4 6 3 21 Etheostoma edwini 2 12 3 6 4 10 4 Etheostoma swaini 6 1 12 18 10 1 1 3 3 Percina austroperca 3 3 14 1 Percina nigrofasciata 160 186 194 113 40 39 18 17 27 3 9 Elassoma zonatum 1 1 2 5 Trinectes maculatus 1 1 Total 981 1668 643 851 865 659 2032 453 491 1251 3579 980 ANote that in a later report Macrhybopsis sp. cf. aestivalis was reported in this watershed (O’Neil and Shepard 2011). In the current study, these may have been included in the numbers of Hybopsis sp. cf. winchelli. Table 5. Historical and current fish species in the Little Choctawhatchee River watershed (Auburn University Natural History Museum 1982; Boschung and Mayden 2004; B. Kuhajda, University of Alabama, Tuscaloosa, AL, pers. comm.; Mettee et al. 1996; Morris 2002). Species Commmon name Historical data Current study Icthyomyzon gagei Hubbs and Trautman Lamprey X Lepisosteus oculatus Winchell Spotted Gar X Lepisosteus osseus (L.) Longnose Gar X Amia calva L. Bowfin X Anguilla rostrata (Lesueur) American Eel X Cyprinella venusta Girard Blacktail Shiner X X Hybopsis sp. cf. winchelli Girard Undescribed chub X X 274 Southeastern Naturalist Vol. 12, No. 2 Table 5, continued. Species Commmon name Historical data Current study Lythrurus atrapiculus (Snelson) Blacktip Shiner X X Notemigonus crysoleucas (Mitchill) Golden Shiner X X Notropis amplamala (Pera and Armbruster) Longjaw Shiner X X Notropis longirostris (Hay) Longnose Shiner X X Notropis maculatus (Hay) Taillight Shiner X Notropis texanus Girard Weed Shiner X X Opsopoeodus emiliae Hay Pugnose Minnow X Pteronotropis merlini Suttkus and Mettee Orangetail Shiner X X Semotilus thoreauianus Jordan Dixie Chub X X Carpiodes cyprinus Lesueur Quillback X Carpiodes velifer (Rafinesque) Highfin Carpsucker X Erimyzon sucetta (Lacepède) Lake Chubsucker X X Minytrema melanops (Rafinesque) Spotted Sucker X Moxostoma poecilurum Jordan Blacktail Redhorse X X Ameiurus natalis (Lesueur) Yellow Bullhead X X Ameiurus nebulosus (Lesueur) Brown Bullhead X Ictalurus punctatus (Rafinesque) Channel Catfish X Noturus funebris Gilbert and Swain Black Madtom X Noturus gyrinus (Mitchill) Tadpole Madtom X Noturus leptacanthus Jordan Speckled Madtom X X Esox americanus Gmelin Redfin Pickerel X X Esox niger Lesueur Chain Pickerel X Aphredoderus sayanus (Gilliams) Pirate Perch X X Labidesthes sicculus (Cope) Brook Silverside X X Fundulus olivaceus (Storer) Blackspotted Topminnow X X Gambusia holbrooki Girard Eastern Mosquitofish X X Ambloplites ariommus Viosca Shadow Bass X Centrarchus macropterus (Lacepède) Flier X Lepomis auritus (L.) Redbreast Sunfish X Lepomis cyanellus Rafinesque Green Sunfish X X Lepomis gulosus Cuvier Warmouth X X Lepomis macrochirus Rafinesque Bluegill X X Lepomis marginatus (Holbrook) Dollar Sunfish X X Lepomis megalotis (Rafinesque) Longear Sunfish X X Lepomis microlophus (Gűnther) Redear Sunfish X X Lepomis miniatus Jordan Resdspotted Sunfish X X Micropterus punctulatus (Rafinesque) Spotted Bass X X Micropterus salmoides (Lacepède) Largemouth Bass X X Pomoxis annularis Rafinesque White Crappie X Pomoxis nigromaculatus (Lesueur) Black Crappie X X Ammocrypta bifascia Williams Naked Sand Darter X Etheostoma colorosum Suttkus and Bailey Coastal Darter X X Etheostoma davisoni Hay Choctawhatchee Darter X X Etheostoma edwini (Hubbs and Cannon) Brown Darter X X Etheostoma parvipinne Gilbert and Swain Goldstripe Darter X Etheostoma swaini (Jordan) Gulf Darter X X Percina austroperca Thompson Logperch X Percina nigrofasciata (Agassiz) Blackbanded Darter X X Elassoma zonatum Jordan Banded Pygmy Sunfish X X Trinectes maculatus (Bloch and Schneider) Hogchoker X Total 39 52 2013 J.M. Miller and P.M. Stewart 275 Discussion Mussels Numerous studies have reported decreases in abundance and diversity of freshwater mussel assemblages in riverine systems of the southeastern United States (Hughes and Parmalee 1999, McGregor and Garner 2004, Pilarczyk et al. 2006). Pilarczyk et al. (2006) found no overall decrease in the number of mussel species, but found decreases in the number of candidate species (for threatened or endangered status) at a site and the number of sites at which candidate species were found in the Gulf Coastal Plains. Pilarczyk et al. (2006) reported declines in Hamiota australis, Pleurobema strodeanum, and Fusconaia burkei (previously listed as candidates for federal protection), which were historically recorded in the LCR watershed. A more recent study by Gangloff and Hartfield (2009) reported finding several new populations of the candidate species Ptychobranchus jonesi (now federally endangered) in the Gulf Coastal Plains, which differs from the findings of Pilarczyk et al. (2006). These new findings were probably due to low water years and refined habitat searches in the Gangloff and Hartfield (2009) study, which resulted in higher detectability. Gangloff and Hartfield (2009) also sampled two sites in the LCR after the current study, resulting in no mussels found at LCR2 and only V. lienosa (n = 8) found at site LCR4, which collaborated the results from the current study. Due to urban and agricultural inputs to the LCR, mussels were expected to decline from historical densities, since at the time of the study four of the 11 species recorded historically were either candidate species or Medionidus acutissimus, a threatened species (Blalock-Herod et al. 2002, Pilarczyk et al. 2006, Williams et al. 2008). Five of the same sites in our study were sampled by Blalock-Herod et al. (2005), which reported no mussels at two sites, and one to two species (V. lienosa and Quadrula succissa) at three sites (LCR3 and LCR4 had both species and Panther Creek had only V. lienosa) in the LCR watershed. No mussels were collected at Bear Creek by Blalock-Herod et al. (2005) or in the current study, but a portion of this site was deep (>2 m) and impounded by Castor canadensis Kuhl (Beaver), allowing only the submerged edges and shallows to be searched. This limitation could be problematic for species detection due to deep habitats, but SCUBA/snorkeling were not implemented in the current study. Additionally, sites searched for mussels were near road crossings, which may suggest that future surveys should include areas within the LCR watershed that are more secluded from direct anthropogenic influences. Mussels not found in the current study that were historically collected included H. australis, P. strodeanum, F. burkei, M. acutissimus, Elliptio arctata, E. pullata, Lampsilis straminea, and Q. succissa. Villosa lienosa was the only mussel recently collected at historically sampled sites, except at Panther Creek where Toxolasma sp. was also found. Panther Creek historically had also yielded P. strodeanum, F. burkei, V. vibex, E. arctata, and E. pullata (Blalock-Herod et al. 2005, Williams et al. 2008). These results indicated a dramatic decline in mussel species throughout the LCR watershed. This decline is in spite of the increased sampling effort (16 sites), which should have greatly improved the detectability 276 Southeastern Naturalist Vol. 12, No. 2 of mussels in the watershed (MacKenzie et al. 2006). The disappearance of these sensitive taxa are a clear indicator of disturbance in the system. Elevated nutrients (Miller 2009; Mullen 1997, 2000, 2003) and extensive areas of unconsolidated substrate (sedimentation, primarily coarse sandy substrates) are some of the local impacts that have been observed in this area (Miller 2009, O’Neil and Shepard 2011). Additionally, mussels were not found directly downstream of the Beaver Creek WWTP, a pattern that had been observed in other studies with WWTPs (Gangloff et al. 2009, Goudreau et al. 1993, Horne and McIntosh 1979). However, mussels were found further downstream after Beaver Creek merged with another stream (Newton Creek). Of the species found historically in the LCR, M. acutissimus (USFWS 1993), H. australis, P. strodeanum, and F. burkei are listed as federally threatened under the Endangered Species Act (USFWS 2012). Pleurobema strodeanum, F. burkei, and M. acutissimus are Alabama state-ranked as high conservation concern and H. australis and E. arctata are ranked highest conservation concern, with M. acutissimus in the process of being moved to highest conservation concern in the state (Jeff Garner, Alabama Department of Conservation and Natural Resources, Florence, AL, pers. comm.). Crayfishes Crayfishes are a threatened fauna in the United States, with about half of all species recommended for some level of protection (Helfrich and DiStefano 2003, Lodge et al. 2000, Taylor et al. 1996). Crayfishes are vulnerable to habitat destruction from dams, erosion, siltation, and water pollution (Helfrich and DiStefano 2003, Lodge et al. 2000). In the LCR watershed, Procambarus okaloosae has been listed as species of high conservation concern in Alabama, while P. suttkusi, C. latimanus, and C. polychromatus have been listed as moderate conservation concern, and C. diogenes has been listed as lowest conservation concern (Smith et al. 2011). There have been several crayfish studies in the Choctawhatchee River watershed (Baker et al. 2008, Fitzpatrick 1990, Heath et al. 2010). Historical accounts of crayfishes in the LCR watershed were limited to three species (P. suttkusi, P. okaloosae, and C. polychromatus [identified as C. (Tubericambarus) sp. B in Heath et al. 2010]) that had been previously found in 2004 (Heath et al. 2010). Procambarus suttkussi, a common species throughout the Choctawhatchee River watershed, was thought to be restricted to this watershed (Bouchard 1976, Fitzpatrick 1990) until Heath et al. (2010) found it in the Yellow and Conecuh River watersheds as well. Additionally C. polychromatus and P. okaloosae had been found within this area of southeast Alabama (Heath et al. 2010, Miller et al. 2005). An increase in the number of crayfish species found in the area was not unexpected due to the limited research previously conducted in the southern coastal plains and specifically in the LCR watershed. The three species previously unreported represent new records for the LCR watershed, but these species were known to occur in the Choctawhatchee River watershed. Procambarus spiculifer, known from almost every watershed in Alabama (Schuster and Taylor 2004) 2013 J.M. Miller and P.M. Stewart 277 but uncommon in the Choctawhatchee drainage (Baker et al. 2008; Heath 2008; J.M. Miller, unpubl. data), was found at one LCR site. Cambarus latimanus has been collected sporadically in low numbers in the Choctawhatchee River watershed (e.g., Heath 2008). It was not uncommon in the current study to collect the burrowing crayfish C. diogenes by electrofishing at several sand-substratedominated sites. The number of individuals of crayfish collected was lowest from August to October 2007 (Miller 2009). This finding was probably due to the 2007–2009 droughts that occurred during the study, which were especially severe during the summer of 2007 (NOAA 2007). In addition, habitat quality declined at several of the sites due to extensive sand movement resulting in extensive embeddedness at some sites. The unnamed tributary (site 7), an extensively embedded site, exhibited a decline in crayfish densities over the course of the present study. Additional sandy sediment accumulation engulfed much of the available habitats at this location over the duration of this study. Beaver Creek, which was also dominated by shifting sand substrates (extensively embedded) and suffered from intense urban alterations, had very few crayfishes. Procambarus okaloosae was collected at the more disturbed sites (including downstream of WWTPs), in a 303d-listed stream in the urban area (including in Heath et al. 2010), and in a Beaver impoundment. This species had been thought to be endemic to the Perdido, Escambia/Conecuh, and Yellow River watersheds in Alabama and Florida (Schuster and Taylor 2004), but was recently collected in the Choctawhatchee River watershed (Heath et al. 2010). Fishes More species of fish were found in the present LCR study than historically recorded, which may have been due to the increased sampling effort in the area. The five historically reported species not collected during this study (Carpiodes cyprinus, Carpiodes velifer, Noturus gyrinus, Noturus funebris, and Etheostoma parvipinne) may be among the more sensitive species and absent due to drought conditions during the sampling period or due to anthropogenic influences. It is noteworthy that C. cyprinus and C. velifer typically inhabit deeper water and are found in smaller streams during spawning (Boschung and Mayden 2004). In addition, the exact sites where N. gyrinus and N. funebris had been historically found were not sampled in the current study. It is possible that Macrhybopsis sp. cf. aestivalis was collected in the current study but not recognized, since more recent samples indicated findings of this taxon (O’Neil and Shepard 2011). Acipenser oxyrinchus desotoi Vladykov (Gulf Sturgeon), federally listed as threatened (USFWS and GSMFC 1995), and Alosa alabamae Jordan & Evermann in Evermann (Alabama Shad), a species of concern (NOAA and NMFS 2008), were not collected historically or during the current study, though these species do occur in the Choctawhatchee River drainage. No exotic fish species were collected by our efforts or in the past in this watershed, though Lepomis auritus and Pomoxis annularis are noted as introduced (Boschung and Mayden 2004). 278 Southeastern Naturalist Vol. 12, No. 2 Potential effects of reservoir construction After impoundment of a river or stream, alterations occur both downstream and upstream of a reservoir due to modification of seasonal flow, isolation of headwaters from downstream reaches (loss of connectivity), and changes in habitat and nutrient characteristics (Kashiwagi and Miranda 2009, Yeager 1993). These alterations can modify assemblage composition (Pyron et al. 1998), altering the community from one containing fluvial specialists to a greater dominance by macrohabitat generalists (Herbert and Gelwick 2003, Kashiwagi and Miranda 2009). A reservoir on the LCR, if built, will likely be highly eutrophic as suggested by recent nutrient levels (Miller 2009). As the population in the region continues to grow, anthropogenic influences will further stress this ecosystem and its water quality. The biodiversity of fishes and crayfishes in the area currently indicates a diverse system, though in many areas fish assemblages are composed of predominately lentic species. Reductions in water quality and physical habitat, as well as food-web disturbances (resource effects and altered community composition and interactions) lead to biological degradation in urban catchments (Paul and Meyer 2001, Suren 2000). Impacts, including impoundment, will continue to degrade this system until advancements are made in the protection of this watershed. Conclusions Rarely are there sufficient data available so that an adequate past versus present comparison can be made. While the overall study was a pre-dam assessment, we herein described the mussel, crayfish, and fish assemblages of a small river and several tributaries in a mixed urban and agricultural watershed. A nearby river, the Cahaba River, AL, has experienced the disappearance of about 25% of its mussel species due to damming, sediment input, and o ther stressors, with similar declines of fish species thought to have occurred (Nijhuis 2009). This decline is minor in comparison to the current study, where the LCR watershed may have lost nearly 75% of its mussel species. Fish declines were found specifically at individual sites in the current study (Miller 2009), and five species were not detected in the LCR watershed in spite of improved detection capabilities due to greatly increased sampling effort, which suggests that they may no longer inhabit this watershed. If impounded, this diverse riverine ecosystem will likely experience loss in its fish and crayfish assemblages. Current fish abundance and diversity will most likely decline, and tolerant taxa will increase with urbanization (Onorato et al. 2000, Paul and Meyer 2001). The sensitivity of mussels serves as an early indicator for problems in the surrounding environment (Nijhuis 2009). Blalock-Herod et al. (2005) and Pilarczyk et al. (2006) showed that the populations of previously candidate (now federally listed) mussel species have declined in the entire Choctawhatchee River watershed. Continued development, along with the addition of a dam and reservoir will further stress this ecosystem and its biological integrity will most likely decline as the urban region expands. 2013 J.M. Miller and P.M. Stewart 279 Acknowledgments We thank Tom Simon (Indiana Biological Survey) and Guenter Schuster (Richmond, Kentucky) for confirmation of crayfishes; Doug Shelton (Alabama Malacological Research Center) for confirmation of mussels; and Pat O’Neil (Geological Survey of Alabama) for confirmation of fishes. 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