Graduate Theses & Dissertations

Conservation genetics of Redside Dace (Clinostomus elongatus)
Recent range reductions of endangered species have been linked to urban development, increased agricultural activities, and introduction of non-native species. I used Redside Dace (Clinostomus elongatus) as a focal species to examine the utility of novel monitoring approaches, and to understand historical and contemporary processes that have influenced their present distribution. I tested the efficacy of environmental DNA (eDNA) to detect Redside Dace, and showed that eDNA was more sensitive for detecting species presence than traditional electrofishing. Parameters such as season, number of replicates, and spatial versus temporal sampling need to be accounted for when designing an eDNA monitoring program, as they influence detection effectiveness and power. I also assessed the species’ phylogeographic structure using both mitochondrial and microsatellite DNA analysis. The data from the microsatellite markers indicate that Redside Dace populations are genetically structured, with the exception of several populations from the Allegheny River basin. Combined sequence data from three mitochondrial genes (cytochrome b, ATPase 6 and ATPase 8) indicated that Redside Dace persisted within three Mississippian refugia during the last glaciation. Secondary contact between two lineages was indicated by both mitochondrial and microsatellite data. The combined results from the eDNA and conservation genetics studies can be used to inform Redside Dace recovery efforts, and provide a template for similar efforts for other aquatic endangered species. Author Keywords: eDNA, endangered, genetics, phylogeography
Ecological and morphological traits that affect the fitness and dispersal potential of Iberian pumpkinseed (Lepomis gibbosus)
The Pumpkinseed (Lepomis gibbosus) is a sunfish that is endemic to eastern portions of Canada and the United States. During the late 19th century, the species was introduced into Europe, and it is now present in over 28 countries. Previous attempts to determine the characteristics that can predict the spread of non-indigenous species have been largely unsuccessful, but new evidence suggests that phenotypic plasticity may help to explain the dispersal and range expansion of some organisms. Experimental comparisons on lower-order taxa have revealed that populations from areas outside of their native range are capable of exhibiting stronger levels of phenotypic plasticity than counterparts from their source of origin. Using Pumpkinseed, I conducted the first native/non- native comparison of phenotypic plasticity in a vertebrate. Progeny from adult Pumpkinseed collected in Ontario, Canada and the Iberian Peninsula (Spain) were reared under variable water velocities, habitat type and competitive pressures, three ecological factors that may affect the dispersal potential of fishes introduced into novel aquatic systems. Differences in phenotypic plasticity, assessed from a morphological perspective, were compared among populations using a traditional distance-based approach. All populations exhibited divergent morphological traits that appeared to be inherited over successive generations. In each experiment, all populations responded to environmental change by developing internal and external morphological forms that, in related taxa, enhance and facilitate foraging and navigation; however, non-native populations always exhibited an overall lower level of phenotypic plasticity. Pumpkinseed from non-native areas may have exhibited a reduction in phenotypic plasticity because of population-based differences. Nevertheless, all Pumpkinseed populations studied were capable of exhibiting phenotypic plasticity to novel environmental conditions, and develop morphological characteristics that may enhance fitness and dispersal in perturbed areas. Author Keywords: Invasive species, Morphology, Phenotypic plasticity, Pumpkinseed sunfish, Reaction norm

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