Publication Date

8-2023

Advisor(s) - Committee Chair

Jarrett Johnson, Keith Philips, Philip Lienesch

Degree Program

Department of Biology

Degree Type

Master of Science

Abstract

Biodiversity is an essential component of natural environmental dynamics. Unfortunately, diversity is threatened by human activities and relies on conservation efforts. An important aspect of biodiversity conservation lies in protecting population connectivity and gene flow. In the mid-1900s, many Kentucky rivers were dammed, creating deep, lentic reservoirs in the valleys once occupied by dynamic, lotic rivers. For species inhabiting the rivers and associated tributaries, the central reservoirs may reduce connectivity among populations and impose a barrier to gene flow. The connectivity of populations on landscapes altered by the creation of reservoirs can be assessed by merging the principles of landscape ecology and the techniques of population genetics into a study of landscape genetics. Prior studies have shown that amphibian species can be used as indicator species to evaluate the effects of habitat fragmentation. I collected samples of Southern Two-Lined Salamanders (Eurycea cirrigera) from tributaries surrounding two Kentucky Lakes: Barren River Lake and Nolin Lake, which were dammed in 1963 and 1964, respectively. I prepared a reduced-representation genetic library using a 3RAD protocol, and sequenced DNA from individual salamanders to identify SNPs (single nucleotide polymorphisms). I then used several methods to identify genetic clusters and assess genetic variation within and between sampling locations and sites. I also performed a series of isolationby- distance and resistant landscape models to determine the least-cost path of gene flow between subpopulations. This analysis showed population structure corresponded heavily with sample sites at both locations, though differentiation of populations was not the result of isolation-by distance at the Barren location. Landscape analyses, including least-cost path models, do show an effect of dam construction at the Barren and Nolin reservoirs. Incomplete genetic data possibly resulting from the large size of the E. cirrigera genome posed a large challenge in assessing landscape effects on population structure, warranting further study.

Disciplines

Biology | Ecology and Evolutionary Biology | Genetics and Genomics | Life Sciences

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Available for download on Thursday, July 18, 2024

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