Comparative phylogeography and conservation genetics in two lizard species (Australia, Missouri)

The development of highly variable molecular markers and powerful analytical techniques to take advantage of the wealth of information contained in those markers has allowed for unprecedented detail and sophistication in population genetic analyses. Here I present applications of these markers and techniques to two systems: the complex of sexual and hybrid parthenogenetic Bynoe's geckos (Heteronotia binoei) distributed throughout Australia; and populations of collared lizards (Crotaphytus collaris) restricted to fragmented desert-like glade habitat in the Ozark Mountains of Missouri, where they are listed as a threatened species. In H. binoei I compare the structure of sexual and parthenogenetic populations, and estimate the ages of parthenogenetic clones. My analyses show that the three sexual races considered here diversified in eastern Australia 4--9 million years ago and expanded westward into their current distributions. The two mitochondrial DNA classes of parthenogens, formed via hybridization between sexual races, are considerably less than one million years old and have spread very rapidly to the east following initial formation in western Australia. Range expansion is continuing in at least one of these classes. The results are combined with ecophysiological analyses of my collaborator in order to understand the nature of adaptation and evolutionary success in parthenogenetic H. binoei. In C. collaris, I combine hypervariable microsatellite DNA markers with field measurements of body size, population size, and dispersal to examine the effects of controlled forest burning on the structure and viability of collared lizard glade populations. I show that glade populations within burned forests have higher population densities and average between-glade dispersal distances than those in unburned forests. In addition, populations in burned areas have marginally higher genetic variability and genetic connectedness. These results suggest that controlled burning as a conservation tool can improve the viability of collared lizard populations and restore a metapopulation structure that was lost as glade populations became fragmented as a result of fire suppression.