Date of Graduation

5-2021

Document Type

Thesis

Degree Name

Master of Science in Biology (MS)

Degree Level

Graduate

Department

Biological Sciences

Advisor/Mentor

Douglas, Marlis R.

Committee Member

Douglas, Michael E.

Second Committee Member

Siepielski, Adam M.

Keywords

Arkansas; Collared lizard; Conservation genetics

Abstract

Habitat reduction and fragmentation can isolate populations and decrease genetic diversity, making them susceptible to local extirpation. Additionally, geographic barriers can further impede dispersal among populations thus reducing gene flow. Field studies suggest these factors may be responsible for the decline in Eastern Collared Lizard (Crotaphytus collaris) populations in Arkansas. To address the impacts of habitat loss and fragmentation on the Eastern Collared Lizard (C. collaris) in Arkansas, I used DNA fragment analysis to examine genetic diversity, population structure and connectivity among C. collaris populations. I do so herein by employing microsatellite data from 138 adults across 11 loci to evaluate genetic diversity parameters and connectivity within and among populations in Arkansas. Results revealed that populations in geographic proximity are more genetically similar than populations more distant and isolated. Migration rates were higher within rather than between sites, ranging from 0.80 to 0.90, suggesting most populations are demographically independent and could comprise ‘Management Units’ (MUs). However, a Mantel test for isolation by distance (IBD) across all sites indicated a non-significant correlation between genetic and geographic distances. An Analysis of Molecular Variance (AMOVA) showed the majority of genetic variance exists within/among individuals (74%) and within populations (26%), which are moderately, but not significantly differentiated (FST=0.26). Results from assignment tests (Structure) and a Discriminant Analysis of Principal Components (DAPC) analyses suggest 5 or 8 distinct gene pools. High-population admixture characterized sites in Baxter and Stone counties, comprising the majority of samples (N=75). Overall, these data indicate populations are genetically isolated and susceptible to potential expiration. To mitigate loss of populations, local management, and conservation efforts such as habitat restoration and translocations will be beneficial if they stabilize or increase population sizes, genetic diversity and promote gene flow in C. collaris in Arkansas.

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