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

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species and the fact that the nonnative species have been collected within the upper Greenbrier River exemplifies the importance of these studies. Each of the following nonnative congeners are, or are hypothesized to be, expanding their range in the upper New River system. The spotfin shiner, Cyprinella spiloptera, is native to the Greenbrier River system, is a slow water generalist, and varies little in spatial and temporal habitat use (Vadas 1992). Cyprinella spiloptera is often found in small to moderately large streams over a variety of different substrates and tends to gather in pools along the banks of streams (Gibbs 1957). The whitetail shiner, Cyprinella galactura, is native to the Tennessee River drainage. This species is often found in rocky runs of small streams and less frequently found in pools or riffles (Gibbs 1961). Cyprinella galactura has, at some point, been introduced to the upper Greenbrier watershed, becoming increasingly abundant after exhibiting minor initial populations (Wellman 2004). There is also evidence of intergeneric hybridization of Cyprinella galactura with a threatened confamiliar species (Burkhead 1983) and with Cyprinella spiloptera (Gibbs 1961). The New River shiner, Notropis scabriceps, is endemic to the New River (Hocutt et al. 1978). It is often found in sandy/rocky runs and flowing pools of small streams (Jenkins and Burkhead 1994). The telescope shiner, Notropis telescopus, is native to the Cumberland and Tennessee Rivers on the east side and the White, St. Francis, and Little River drainages on the west side of the Mississippi River drainage (Gilbert 1969a). It prefers clear, flowing waters of medium sized upland creeks and has been introduced and established in the New River (Gilbert 1969a). Since being introduced to the New River the telescope shiner has experienced widespread population increases and has become 19
ubiquitous, appearing in all channel units (personal observation). Similar preferred temperatures of Notropis sabriceps and Notropis telescopus have been measured to be 19.3°C and 20°C respectively (Cherry et al. 1977, Shingleton et al. 1981). Effort must be applied to gain understanding of the interactions that are occurring between native and introduced species currently found in the upper Greenbrier watershed. Field sampling and population analyses are not enough to quantify competitive interactions and indicators of competitive exclusion among congenerics (Herbold and Moyle 1986). Several studies have demonstrated the importance of interspecific interactions on fish distributions through both horizontal and vertical spatial scales. Natural and artificial environments were used to show that exploitation and interference competition were important factors involved in regulating the distribution of three Cottus species (Finger 1982). Space was determined to be the competitive dimension allowing the coexistence of the three species. Field observations have been used to document the spatial variation of eight cyprinid fishes and to make inferences on the role of habitat segregation in structuring the community (Baker and Ross 1981). However, it has been suggested that aquarium studies should be utilized to detect interspecific interactions between potentially competing species (Simberloff 1981, Ross 1991). Observations of six Ozark minnow populations indicated vertical stratification when individuals were placed among congeneric or confamilial sympatric species (Gorman 1988). Overlaps of water column positions suggest an overlap in the spatial aspect of pelagic minnow species’ ecological niches (Baker and Ross 1981, Gorman 1988). Similarly, aquarium studies can be used to detect shifted habitat usage as a consequence of introducing similar nonnative species (Marchetti 1999). However, shifts in vertical distribution behavior of 20
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: in the upper Greenbrier River and o
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 and 38: Introduction Non-native fishes nega
Page 39 and 40: native cyprinids on their native co
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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