Speciation, niche modeling, phylogeography, population genetics, historical dna, matrix modeling, habitat utilization


The conservation biology field seeks to preserve biodiversity and the processes shaping that variation. Conservation biology is intimately tied to evolutionary research, in order to identify evolutionary distinct lineages that may be in danger of disappearing. Interestingly, patterns and processes of lineage divergence and persistence change with respect to spatial and temporal scale. I seek to evaluate biodiversity, the factors that have shaped this heterogeneity, and how this variability persists. To accomplish this I used a phylogeographic approach as well as niche and population modeling on the Peromyscus maniculatus species group found widely distributed in North America. My emphasis was on the southeastern U.S. species P. polionotus and its distinct beach forms. At a continental scale, I found that environmental niches are likely involved in generating and/or maintaining genetic lineages within the P. maniculatus species group. These findings add to a growing number of studies that have identified lineages occupying different environmental spaces. At a regional scale, I supported the hypothesis that barrier islands on the Atlantic coast of Florida were colonized by an ancestral form of P. polionotus by a single colonization, from the central Florida area. Subsequently, at least two distinct lineages diverged (P. p. phasma and P. p. niveiventris). I also found evidence that suggests that the extinct form of beach mouse (P. p. decoloratus) is part of the P. p. phasma lineage. At the population level, I evaluated changes in genetic diversity in historical samples compared to those that experienced recent human encroachment on natural habitat I used tissue preserved in natural history collections to compare with live-trapped specimens, and found that P. p. niveiventris has maintained historical genetic diversity levels. I suggest that the continuation of historical levels of genetic diversity is due to the presence of a single large area iv of continuous habitat in the central portion of the species’ current distribution. Finally, I evaluated the importance of scrub and beach habitat to the population dynamics of beach mice. Beach mice have traditionally have been associated with beach dunes rather than with the scrub habitat found more inland on barrier islands. Using almost three years of capture-recapture data from Cape Canaveral Air Force Station (CCAFS), I created a stochastic matrix model to assess the relative contribution of populations from the two different habitats to a variety of demographic measures. Both field data and model results provided evidence that the population dynamics of beach mice may rely much more on scrub habitat than formerly documented. Overall, my research emphasized a hierarchical approach to evaluate biodiversity and the processes shaping differentiation at different spatial and temporal scales. The methods and findings give insight into speciation at different scales, and can be applied to a wide range of taxa for questions related to evolutionary and conservation biology.


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Graduation Date





Parkinson, Christopher


Doctor of Philosophy (Ph.D.)


College of Sciences



Degree Program

Conservation Biology; Ecology and Organismal Biology








Release Date

August 2015

Length of Campus-only Access

5 years

Access Status

Doctoral Dissertation (Open Access)


Dissertations, Academic -- Sciences, Sciences -- Dissertations, Academic

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