Term of Award
Master of Science in Biology (M.S.)
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Thesis (open access)
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This work is licensed under a Creative Commons Attribution 4.0 License.
Department of Biology
Committee Member 1
Committee Member 2
Unpaved roads may provide uniform microhabitat characteristics and impart edge effects in the adjacent landscape that mediate environmental pressures acting on small vertebrates. These features may allow species that are associated with recent disturbance to persist in aging forest patches. Further, epigenetic mechanisms such as DNA methylation may provide these species the phenotypic plasticity necessary to occupy multiple habitats with different environmental conditions. To understand how small vertebrates use unpaved roads, the relative abundance and occurrence of Florida scrub lizards (Sceloporus woodi) and six-lined racerunners (Aspidoscelis sexlineata) were quantified using visual encounter surveys along unpaved roads bordered by habitat patches of different age classes and under different management regimes. To explore lizard microhabitat associations along unpaved roads, the proportion of several microhabitat characteristics within the road adjacent habitat (≤ 10m from road edge) were also quantified. In addition, Sceloporus woodi were captured from unpaved road and forest interior habitats (≥ 15m from road edge) to understand how small vertebrates use unpaved roads and DNA methylation to respond to environmental pressures. Variation in Sceloporus woodi diet, ectoparasite count, and DNA methylation was compared among 1) all road habitats, 2) all interior habitats, and 3) between road and interior habitats. Neither relative abundance nor occurrence of either species was affected by the road adjacent habitat. Sceloporus woodi relative abundance was positively correlated with the proportion of shade, whereas Aspidoscelis sexlineata relative abundance was positively correlated with substrate temperature. Sceloporus woodi from unpaved roads also had a more uniform diet and ectoparasite counts than those in stand interiors. Additionally, diet, ectoparasite exposure, and habitat type were correlated with DNA methylation changes within individuals, and three times as many differentially methylated regions were detected among lizards from forest interiors compared to lizards from unpaved roads. These results indicate molecular and non-molecular aspects of species biology are affected by unpaved roads. New habitat conditions along the road surface and in the adjacent landscape also appear to allow small disturbance dependent vertebrates to occupy previously inhospitable habitat. In doing so, these features may enhance connectivity and population viability in fragmented landscapes.
Tevs, David, "Effects of Unpaved Roads on Relative Abundance and Epigenetics of Early Successional Lizards" (2022). Electronic Theses and Dissertations. 2500.
Research Data and Supplementary Material