STATE : Alabama PROJECT NUMBER: E-1 SEGMENT: 2 STUDY NUMBER: 5 BLACK WARRIOR WATERDOG STATUS SURVEY FINAL REPORT 1991-92 BY MARK A. BAILEY Dece:nber, 1992 Approved by: FINAL REPORT State: Alabama Study Title: Black Warrior Waterdog Status Survey Study No. 5 Project Title: Alabama Endangered Wildlife Projects Project No. E-1 Period Covered: 1 December 1990 to 30 September 1992 Prepared by: Alabama Natural Heritage Program Mark A. Bailey, Principal Investigator Notice of nomenclatural conventions used in this report: In the absence of a Latin name, and for the sake of clarity and convenience, the undescribed Nectwus of the upper Black Warrior River system will be referred to by its generally accepted common name, the Black Warrior waterdog. Despite uncertainty over the proper taxonomic placement of other species (N. beyeri and/or N. a/abamensis) with which the Black Warrior waterdog is sympatric in the lower portion of its range, it/they will be referred to as N. a/abamensis. Abstract: The Black Warrior waterdog, an undescribed form of Necturus endemic to the upper Black Warrior River system of Alabama, was surveyed for at 66 sites in nine counties from November, 1990 to February, 1992. Although gilled larvae of other salamander genera including Desmognathus, Eurycea, and Pseudotriton were encountered at 28 (45%) of the 62 sites sampled by netting, Necturus specimens referable to the Black Warrior waterdog were found at only four (6%) of the 66 sites netted and/or trapped: the Sipsey Fork of the Black Warrior River, Wmston County (six adults, one larva); Lost Creek, Walker County (one adult); North River and Yellow Creek, Tuscaloosa County (one larva and one subadult, respectively). The Walker and Tuscaloosa county records represent previously unreported occurrences. Presence of larvae indicates recent reproduction in the Sipsey Fork, Lost Creek and Yellow Creek populations. Despite repeated attempts, the Black Warrior waterdog was not confirmed from the Blackburn Fork of the Little Warrior River in Blount County, where it has been collected as recently as 1989. The Alabama waterdog (Necturus a/abamensis), a more common species occurring chiefly below the Fall Line in the Black Warrior River system, was found to be sympatric with the Black Warrior waterdog above the Fall Line in the North River above Lake Tuscaloosa, and was taken from two other Tuscaloosa County sites (Lye Branch and Carroll Creek) below the Fall Line. The upstream limit of sympatry is undetermined. Successful sampling techniques included funnel traps, shocking, and dip netting leaf beds. Sampling was often limited by water depth and availability of nettable leaf bed habitat. Multiple captures occurred at two locations, indicating ' Black Warrior Waterdog Survey 1990-92 2 that where common, waterdogs can be detected without great effort, at least at some sites. All streams sampled showed some degree of degradation from sedimentation, and many appeared to be biologically depauperate. The apparent scarcity or absence of the Black Warrior waterdog at a number of thoroughly sampled sites suggests actual rarity and/or absence in large portions of the upper Warrior Basin. Specimens collected during this study may be representative of an undetermined number of fragmented subpopulations. More intensive work is needed to better determine the degree of fragmentation and to investigate reproductive biology, particularly the susceptibility of eggs and larvae to water quality degradation. Additional work is also needed to determine the condition of populations (if any) occurring in deep water habitats, but results presented in this first range-wide investigation of the Black Warrior waterdog's distnoution suggest that the form is rare, probably critically imperiled due to habitat degradation, and in need of protection. Considering the current rates of industrial and residential development in the Warrior basin and projected future expansion of mineral extraction in the Warrior coal field, unless conditions improve over portions of the upper Black Warrior River system and a way is found to increase the number and size of the remaining waterdog populations, prospects for long-term survival are poor. INTRODUCflON Background The waterdogs of the Black Warrior River system have been assigned, at one time or another, to four different species: Necturus macu/osus, N. alabamensis, N. beyeri. and an undescribed species. Two distinct forms, one with striped larvae and the other with plain or fmely spotted larvae, inhabits the drainage above the Fall Line. The taxonomic status of Necturus in Alabama is confused due largely to the lack of representative series of specimens from critical areas (Mount 1975), and continues to frustrate herpetologists and taxonomists today. Prior to 1937, all of the currently recognized Necturus species of the Gulf drainages were treated as N. macu/osus. Viosca (1937) revised the genus, describing N. a/abamensis from the Black Warrior River near Tuscaloosa. In the same paper was the description of N. beyeri, to which Viosca also assigned specimens from the Tuscaloosa area. Viosca did not examine specimens any great distance upstream from Tuscaloosa, nor did he elaborate on the location of collections relative to the Fall Line. Viosca considered a/abamensis to be a relatively small Necturus (the gravid female holotype measured 168 mm total length), and noted the depressed head and body (and their similarity to maculosus), immaculate venter, and dark line from the corner of the eye through the gills. Larvae were unknown. N. beyeri was characterized as larger (to 223 mm), bead and body sub-cylindric (not depressed), venter spotted, larvae with spots, and adults lacking the dark facial stripes of a/abamensis. Hecht (1958) reassigned akzbamensis as a subspecies of beyeri. Neill Black Warrior Waterdog Survey 1990-92 3 {1963) contended that alabamensis and beyeri occurred in sympatry and that alabamensis should be returned to full species. Gunter and Brode (1964) disagreed with Neill's taxonomy, but noted that specimens of W. beyeri alabamensis" from the Mulberry Fork of the Black Warrior River at Cordova displayed a distinct tendency to have spots arranged in three rows, one down the back and one on each side (a pattern which, incidentally, is suggestive of the larval stripe pattern of the Black Warrior waterdog). Brode (1969) first called attention to the possibility of an undescribed Necturus in the Sipsey Fork of the Black Warrior River, and considered that population to be a new subspecies of maculosus, and Maxson tf.p.l. (1988) also also considered this population to be maculosus. Mount (1975), acknowledging the confused state of Necturus taxonomy in Alabama, tentatively grouped all populations outside the Tennessee drainage as beyeri. Guttman et. a/. (1990) electrophoretically distinguished alabamensis and beyeri as separate species, considered Alabama populations to be alabamensis, and commented that the Black Warrior populations were electrophoretically slightly distinct from other Necturus in the Mobile drainage. Those authors went on to state that based on molecular differences, the striped larval pattern, the presence of other endemic vertebrates in the geologically distinct watershed (e.g., Stemocherus depressus), and Neill's (1963) assertion that two distinct Necturus were to be found in the Black Warrior River just above Tuscaloosa, further assessment of the taxonomic status of the Black Warrior River waterdogs is warranted. A formal species description of the Black Warrior waterdog is currently in preparation by Ashton and others. Description The Black Warrior waterdog is a relatively large, gilled, aquatic salamander with a maximum length of around 200 mm (7.8 inches). Larvae (28-48 mm total length) are dorsally dark brown or black with two light dorsolateral stripes beginning at the nostril, extending posteriorly through the eye, and terminating on the dorsal fm of the tail. Other Gulf drainage Necturus are not known to have striped larvae (Guttman et. aJ. 1990). Subadults (40-100 mm total length) are not conspicuously marked, with little if any spotting, but a dark stripe extends from the nostril through the eye and to the gills. Adults may be spotted or unspotted, and retain the dark eye stripe. The ventral surface of all age classes is plain white. Adults resemble the Neuse River waterdog, N. lewisi, of the Tar and Neuse rivers of North Carolina (Ashton and Peavy 1986). The striped pattern exhibited by the larvae closely resembles that of N. maculosus larvae (Hecht 1958, Brode 1969). Distribution Prior to this study, the Black Warrior waterdog was known from only a few localities, with recent conflTDled records only from the Sipsey Fork in Wmston County and Blackburn Fork in Blount County (Ashton, 1986). Where conditions are favorable, the Black Warrior waterdog probably inhabits larger streams (10 m wide or greater) throughout the upper Black Warrior River system (F'tgUre 1), since many smaller tributaries in the .• Black Warrior Waterdog Survey 1990-92 4 Figurel. Presumed Distnbution of the Black Warrior Waterdog. Dots represent localities reported since 1989. Black Warrior Waterdog Survey 1990-92 5 region go dry in late summer due to little or no recharge from the surrounding Pottsville sandstone and shale. Hydrologic requirements are likely similar to those of N. lewisi in North Carolina, which was found to predominantly occur in streams greater than 15 m wide and deeper than 100 em, and was not found in streams where water flow
Details
-
File Typepdf
-
Upload Time-
-
Content LanguagesEnglish
-
Upload UserAnonymous/Not logged-in
-
File Pages28 Page
-
File Size-