Drainage Evolution and Fish Dispersal in the Central Appalachians: Summary
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f! n r G.S. il \\jì Û id W ¡Lem" Drainage evolution and fish dispersal in the central Appalachians: Summary CHARLES H. HOCUTT University of Maryland, Center for Environmental and Estuarine Studies, Appalachian Environmental Lab- oratory, Frostburg State College Campus, Gunter Hall, Frostburg, Maryland 21532 INTRODUCTION ships on the basis of present species distributional patterns even though complementary geological data are lacking. Thus, it is The study of fish dispersal in the central Appalachians is a stressed that zoogeographic conclusions regarding past drainage perplexing problem to ichthyologists, who often must rely on patterns are best based on facts supported by a combination of geological literature to determine past drainage relationships. geological and biological evidence. Many classical geomorphological treatments of drainage history The central Appalachian mountains are recognized as a major and evolution are often dated (1884—1934), and controversial as area (theater) of stream piracy (Hocutt and others, 1978). The well. Biogeographers sometimes conjecture past drainage relation- Mississippi drainage-Atlantic slope divide probably once stood Figure 1. Present-day drainage of the upper Kanawha River study area with 305-m contour interval (above sea level) superimposed. Indicated contour is reflective of the presumed level of Teays Lake, or Lake Tight, a Pleistocene glacial lake. This illustration is Figure 3 in the corresponding article in Part II. Geological Society of America Bulletin, Part I, v. 90, p. 129-130, 1 fig., February 1979, Doc. no. S90101. 129 Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/90/2/129/3429513/i0016-7606-90-2-129.pdf by guest on 01 October 2021 130 C. H. HOCUTT near the Fall Line, and it has migrated westward through Tertiary and a concentrated field investigation resulted in the formation of and Quaternary time due to the competitive advantages of Atlantic three hypotheses that promote the Gauley River as an avenue of slope streams. Today, the divide remains in the Blue Ridge dispersal for Mississippi basin fauna through the Teays system to Mountains south of Roanoke, Virginia. North of Roanoke, how- the Atlantic slope: (1) Gauley River was a viable alternative for ever, the divide between the New River (Mississippi drainage) and fishes which successfully negotiated the Kanawha Falls area rather Roanoke and James Rivers has migrated 64 to 120 km, 130 to 160 than up the evolving Teays gorge; (2) within the area of discussion, km between the Monongahela and Potomac river divide, and even the Pliocene Appalachian Plateau extended farther east than it does farther between the greater Ohio (Monongahela-Allegheny) and today and was drained principally by Gauley River; and (3) Green- Susquehanna Rivers. brier River, a minor tributary to the Pliocene Teays River, captured The Mississippi basin is the primary center of origin and disper- its present drainage from Gauley River in the Pleistocene and dis- sal of fresh-water fishes east of the Rocky Mountains. The placed the eastern edge of the Appalachian Plateau some 35 km Pliocene-Pleistocene Teays River system, precursor to the New- west of its original position. Biological and geological evidence in Kanawha River system, is considered the main route of dispersal support of these hypotheses is offered. east to the Atlantic slope (Ross, 1969; Jenkins and others, 1972) and north to the upper Ohio River system (Hocutt and others, SUMMARY 1978). It is a purpose of this manuscript to review the routes of fish dispersal in the central Appalachians and present new thoughts on In summary, there is evidence that the Appalachian Plateau once the role of the Teays River system as an agent for fish dispersal. extended as far east as the present-day divide between the Green- Among these are a reconsideration of the falls of the Kanawha brier and James Rivers along Allegheny Mountain (Fig. 1). This ex- River as an absolute barrier to the upstream movement of fishes, tended plateau was drained principally by the Gauley River during and the roles of the Gauley and Greenbrier Rivers in fish dispersal. Pliocene time. During the Pleistocene, glacial ponding occurred in the Teays drainage which facilitated the dispersal of certain fish HYPOTHESES species but which inhibited the dispersal of others. Fishes moving up Teays River, possibly to escape the frigid impoundment waters, The Pliocene Teays River was the major drainage from the east- probably used the shoreline of glacial Lake Tight to successfully central United States to the ancestral Mississippi River. It is gener- negoiate the Kanawha Falls area (Fig. 1). Once above the Falls area, ally agreed that the New-Kanawha River drainage (Fig. 1) in North fishes found the Gauley River a strenuous route, but less rigorous Carolina, Virginia, and West Virginia is a remnant of the Teays than the evolving Teays-New River gorge. Simultaneously, in the channel (Hocutt and others, 1978). The confluence of New River Pleistocene, Greenbrier River breached a major divide between it and Gauley River forms the Kanawha River at Gauley Bridge, West and Old Gauley River, and rapidly extended its drainage along a Virginia. Less than 2.0 km downstream of the confluence are the limestone belt. Faunal exchanges occurred along the Gauley- 7.3-m-high Kanawha Falls, which have long been considered a Greenbrier interface at this time and may have facilitated the dis- barrier to fish dispersal into the upper Kanawha (New) River persal of Teays stock to the Atlantic slope by bypassing the Teays drainage. The period of inception of the Falls is unknown. Other gorge. falls above Kanawha Falls are Wylie, Bull, and Sandstone (Hocutt and others, 1978), all located within the impressive New River REFERENCES CITED gorge. The New River gorge, now incised as much as 457 m into the Hocutt, C. H., Denoncourt, R. F., and Stauffer, J. R., Jr., 1978, Fishes of the Greenbrier River, West Virginia, with drainage history of the cen- Appalachian Plateau, extends from the vicinity of the present tral Appalachians: Journal of Biogeography, v. 5, no. 1, p. 59-80. Virginia-West Virginia state line downstream to near the 1979, Fishes of Gauley River, West Virginia: Brimleyana (North confluence with Gauley River, a river distance of ~ 90 km (Fig. 1). Carolina State Museum of Natural History) (in press). It has been suggested that the series of rapids, cascades, and low Jenkins, R. E., Lachner, E. A., and Schwartz, F. J., 1972, Fishes of the cen- falls of the gorge may have hindered downstream as well as up- tral Appalachian drainages: Their distribution and dispersal, in Holt, P. C., ed., The distributional history of the biota of the southern Appa- stream dispersal. While no one of the obstacles may have been lachians, Part III, Vertebrates: Blacksburg, Virginia Polytechnic Insti- formidable within itself, they may have contributed synergistically tute and State University, Resource Division Monograph 4, p. 43- to the formation of the depauperate and unique New River fish 117. fauna (Hocutt and others, 1978). This is based on the fishes com- Ross, R. D., 1969, Drainage evolution and fish distribution problems in the southern Appalachians of Virginia, in Holt, P. C., ed., The distribu- monly identified as originating from and/or being endemic to the tional history of the biota of the southern Appalachians, Part I, Inver- drainage: Exoglossum laurae, Nocomis platyrhynchus, Notropis tebrates: Blacksburg, Virginia Polytechnic Institute and State Univer- scabriceps, Phenacobius teretulus, Etheostoma kanawha, Etheos- sity, Resource Division Monograph 1, p. 277-292. toma osburni, Percina oxyrbyncha, Percina cf maculata, and Cot- tus carolinae ssp. An ichthyofaunal survey of Gauley River in 1976 (Hocutt and others, 1979)' yielded six species not previously reported from above Kanawha Falls: Lampetra aepyptera, Moxostoma eryth- MANUSCRIPT RECEIVED BY THE SOCIETY FEBRUARY 21, 1978 rurum, Ictalurus natalis, Ictalurus nebulosus, Noturus flavus, and REVISED MANUSCRIPT RECEIVED AUGUST 28, 1978 Percina caprodes. This fact, a subsequent review of the literature, MANUSCRIPT ACCEPTED SEPTEMBER 12, 1978 Printed in U.S.A. Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/90/2/129/3429513/i0016-7606-90-2-129.pdf by guest on 01 October 2021.