An Experimental Study of Vertical Habitat Use and Habitat Shifts in ...

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Introductions of non-native fishes have increased dramatically within the past century (Courtenay and Hensley 1980). Drainages with naturally low species diversity, such as the New River drainage of North Carolina, Virginia, and West Virginia, have typically incurred the largest numbers of introduced species (Jenkins and Burkhead 1994). The New River drainage not only has a high proportion of non-native fishes (over 50% nonnative, Wellman 2004), but also includes a diverse endemic fish fauna (bigmouth chub Nocomis platyrhynchus, New River shiner Notropis scabriceps, Kanawha minnow Phenacobius teretulus, Kanawha sculpin Cottus kanawhae, Bluestone sculpin Cottus sp., albino cave sculpin Cottus sp., Appalachia darter Percina gymnocephala, Kanawha darter Etheostoma kanawhae, and candy darter Etheostoma osburni). Within the last half century, range distributions have decreased for many of these New River endemics (Chipps 1993b, Cincotta et al. 1999, Burns 2007), but few research efforts have focused on the relationship or non-relationship between a concurrent increase in nonnative diversity (number of species and population sizes) and a decrease in population sizes and range distributions of native species. Many non-native fishes have recently expanded their distributional ranges within the lower New River drainage and tributaries, such as the 4000 km 2 Greenbrier River watershed of West Virginia, including whitetail shiner Cyprinella galactura, telescope shiner Notropis telescopus, Roanoke darter Percina roanoka, rainbow darter Etheostoma caeruleum, and variegate darter Etheostoma variatum (Wellman 2004). The fish fauna of the Greenbrier River drainage includes seven of the nine New River endemics (excluding Kanawha darter and Bluestone sculpin) and has relative high population sizes of two nonnative minnows, telescope and whitetail shiner. The ecological influences of these non- 33
native cyprinids on their native congeners, New River shiner and spotfin shiner Cyprinella spiloptera, are undocumented, but Burns (2007) estimated population sizes of both introduced species to be greater than the native congeners in most Greenbrier River sampling sites. The objective of this aquaria-based experimental study was to quantify interactions between two congeneric pairs of native (N. scabriceps and C. spiloptera) and non-native (N. telescopus and C. galactura) cyprinids of the New River drainage. The study was designed and conducted following discovery of population declines of N. scabriceps and C. spiloptera in the presence of range expansions and population size increases of the introduced N. telescopus and C. galactura. Methods Specimen collection and transport I collected two species of native minnows (N. scabriceps and C. spiloptera) and two species of their non-native congeners (N. telescopus and C. galactura) with a 1.5m x 3m x 0.3cm mesh seine from the East Fork Greenbrier River, North Fork Deer Creek, Deer Creek, and Meadow Creek. Approximately 100 –130 adults of each species were collected for transport to the laboratory with the following size ranges: N. scabriceps (55 – 82mm SL), N. telescopus (57 – 82mm SL), C. spiloptera (68 – 84mm SL), and C. galactura (68 – 86mm SL). Fishes were transported from stream to laboratory in 189.3L (50 gal) insulated coolers. Water during transport was aerated, salted (
Page 1 and 2: An Experimental Study of Vertical H
Page 3 and 4: Acknowledgements I would like to th
Page 5 and 6: LIST OF TABLES Table 1. Results of
Page 7 and 8: In order for similar species to avo
Page 9 and 10: species diversity should increase (
Page 11 and 12: noting that the abundance of some s
Page 13 and 14: exhibited by species involved; the
Page 15 and 16: new environment (Dueser and Porter
Page 17 and 18: host environment, proposing that a
Page 19 and 20: Hybridization with introduced speci
Page 21 and 22: alteration may reduce the habitat s
Page 23 and 24: in the upper Greenbrier River and o
Page 25 and 26: ubiquitous, appearing in all channe
Page 27 and 28: Literature Cited Addair, J. 1944. T
Page 29 and 30: Gibbs, R. H. 1957. Cyprinid fishes
Page 31 and 32: Lobb, M. D., III. 1986. Habitat use
Page 33 and 34: Paybins, K. S., T. Messinger, J. H.
Page 35 and 36: Chapter 2: An Experimental Study of
Page 37: Introduction Non-native fishes nega
Page 41 and 42: enthic, near-benthic, lower-pelagic
Page 43 and 44: N. telescopus had modes in the lowe
Page 45 and 46: native species pairs were partially
Page 47 and 48: interspecific separation of vertica
Page 49 and 50: MacArthur, R. and R. Levins. 1967.
Page 51 and 52: Table 1. Results of Chi square Test
Page 53 and 54: Total Number of Occurrences 160 140
Page 55: Total Number of Occurrences 160 140

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