Date of Award
Master of Science (MS)
Chemical pollution and nonnative species are two of the major threats facing freshwater fishes. As such, understanding how freshwater fish communities respond to pollution remediation efforts and nonnative fish introductions are primary goals of native fish conservation. Within the Spring River subbasin (SRS) of southeastern Kansas, this study examined the long-term response of riffle fish communities to decreases in heavy metal concentrations, as well as the effects of introduced Blackspotted Topminnow (Fundulus olivaceus) on native Blackstripe Topminnow (Fundulus notatus). The objectives of our research in Chapter 01 of this thesis were to quantify changes in riffle fish community structure across a temporal pollution severity gradient that spanned 1993-1995 (more severe) to 2019-2021 (less severe), and in Chapter 02 we used genetic analyses to identify Fundulus spp. distributions as well as their hybridization frequency. Since the 1990’s, declining heavy metal concentrations from mining remediation have had a positive response on pollution sensitive riffle fish species, including the federally threatened Neosho Madtom (Noturus placidus). In response to this long-term water quality improvement, riffle fish community structure shifted from predominately pollution tolerant species to pollution intolerant species, many of which are species of greatest conservation need (SGCN) in Kansas. This research suggested that pollution legislation designed to improve water quality creates a ripple effect that has the power to stimulate the recovery of imperiled fish species. Regarding Fundulus spp. distributions, we found that after at least 20 years of being introduced to the SRS, the Blackspotted Topminnow remained largely restricted the stream where it was initially found in 2000 (i.e., Shoal Creek) and had not spread to the rest of the SRS other than the Spring River near its confluence with Shoal Creek, which coincides with a small cooling reservoir for a coal-fired powerplant near Riverton, KS (i.e., Empire Lake). As such, Empire Lake may have acted as a dispersal barrier against further Blackspotted Topminnow invasion, allowing native Blackstripe Topminnow to remain the dominant Fundulus spp. throughout the rest of the SRS. However, the limited spread of Blackspotted Topminnow may also be explained by variation in water clarity among streams in the SRS resulting from differences in land use and cover, as widespread agriculture may cause much of the SRS to be too turbid to support Blackspotted Topminnow. In contrast, Shoal Creek is more forested. Furthermore, the hybridization frequency between Fundulus species was greatest in the Spring River directly below and Shoal Creek directly above Empire Lake. Though nonnative Blackspotted Topminnow has hybridized and displaced native Blackstripe Topminnow in Shoal Creek and the lower Spring River directly below Empire Lake, it appears at present that this invasion is contained to Shoal Creek and the Spring River directly below Empire Lake. However, other Ozarkian tributaries of the Spring River where Blackspotted Topminnow have yet to invade may have the clear water that is necessary for their successful establishment, thus monitoring and public outreach is necessary to help prevent the invasion of these streams. Our results demonstrated a conservation success story for native fishes of the Spring River regarding the increased prevalence of pollution-sensitive and oftentimes imperiled species following water quality improvements. Yet, more conservation actions may be necessary in the SRS to help control nonnative Blackspotted Topminnow and restore displaced Blackstripe Topminnow to Shoal Creek.
King, Alexandra, "Chemical and Biological Stressors Threaten Native Fish Diversity in the Spring River Subbasin of Kansas" (2022). Electronic Theses & Dissertations. 397.