"Professional paper presented in partial fulfillment of the requirements for the degree of Master of Science in Wildlife Biology, the University of Montana, Missoula, MT, spring 2007." / Title from PDF title page (viewed Aug. 20, 2007). Includes bibliographical references (p. 15-20).

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 149-168). Also available on the World Wide Web.

The evolution of mating signals has long interested biologists because changes in mating signal production and/or reception can lead to reproductive isolation and speciation. Here, I examine the evolution of the male mating signal (the advertisement call) and the female preference for this call in the Western Toad, Bufo boreas. Call surveys and a morphological study for the occurrence of vocal sacs, which are necessary for producing these calls, reveal that only populations in the northeastern corner of this species’ range produce long, high-amplitude advertisement calls. This is the first study to report among-population variation in the presence of the major mating signal in any animal. Although populations vary in whether or not males call, phonotaxis tests demonstrate that female B. boreas in calling and non-calling populations have the preference for this call. Phylogenetic analyses indicate that the call was lost in the ancestor to modern B. boreas and then secondarily re-evolved in the ortheastern populations. Bufo boreas is one of many toad species that inhabits the Nearctic region. I use phylogenetic analyses of large and small subunit mitochondrial ribosomal DNA sequences to examine the phylogenetic relationships among Nearctic toad species and test previously proposed biogeographic hypotheses for the colonization history of the Nearctic region. This work indicates that the Nearctic Bufo are monophyletic and result from a single colonization event from the Neotropics. Further, fossil and paleogeographic data suggest that this colonization occurred prior to the formation of a contiguous land bridge between the Neotropic and Nearctic regions. Many of the individuals examined in the Nearctic toad study had previously been sequenced for the same gene region. A surprising number of errors were found in the earlier sequences and attributed to the method of sequence generation. In my final chapter, I review the causes and consequences of sequencing error and present a novel method that uses sequence conservation information to detect errors. This approach is exemplified with the unique dataset of replicated sequences, and resources for easily implementing this approach are made available on the Comparative RNA Web Site (http://www.rna.ccbb.utexas.edu/). / text

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Alberta, 2010. / Title from pdf file main screen (viewed on June 11, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Environmental Biology and Ecology, Department of Biological Sciences, University of Alberta. Includes bibliographical references.

Population genetic structure is widespread in many organisms and can be found at small spatial scales. Fine-scale differentiation is the result of ecological and evolutionary processes working together to produce an overall pattern, but the relative importance of these factors in population differentiation is poorly understood. The goals of my research were to describe patterns of population genetic differentiation and to identify ecological and evolutionary factors important for population divergence. To this end, I investigated several aspects of genetic differentiation for three vertebrates in northern California. The focal species were the terrestrial garter snake (Thamnophis elegans) and the common garter snake (Thamnophis sirtalis) that occupy a series of ponds, lakes and flooded meadows in northern California. I found significant genetic differentiation and isolation by distance, as well as correlated patterns of pairwise divergence in both species. Independent estimates of effective population size and bi-directional migration rates also uncovered source-sink dynamics in both species that suggest frequent extinction-recolonization events within a metapopulation context. The generality of source-sink dynamics for an ecologically similar species within the same ecosystem was explored using a third species, B. boreas. I also identified ecological correlates of several population genetic parameters for all three species. Although F[subscript ST] were similar, B. boreas had larger effective population sizes, lower migration rates, lacked source-sink dynamics, and appeared to be in migration-drift equilibrium, indicative of a temporally stable population structure. A clustering analysis identified a series of block faults as a common barrier to dispersal for both garter snakes, and ecological correlates were found to be more similar among response variables than within species. I then compared degree of genetic differentiation at quantitative traits with that at neutral markers to infer strength of selection and adaptive divergence between two ecotypes of T. elegans. Selection on most traits was relatively weak, but strong diversifying selection was found for background coloration, total number of ventral scales and number of infralabials. Overall, my research documented ecological and evolutionary processes associated with population differentiation in a metacommunity and respresents an important contribution toward the unification of ecology and evolutionary biology. / Graduation date: 2005

The western toad (Anaxyrus boreas, formerly Bufo boreas) is one of many amphibian species considered to be at risk of extinction (COSEWIC status is Special Concern). I examined habitat use patterns of the western toad using several methods to gain a better understanding of its habitat requirements. I examined the relationship between relative abundance of the western toad and two sympatric amphibian species (wood frog, Lithobates sylvaticus; and boreal chorus frog, Pseudacris maculata) and habitat features at eight scales of spatial extent at 24 wetlands in the Lake Utikuma region of Alberta, Canada. I radio-tracked adult western toads in three study areas in the Aspen Parkland and Boreal regions of north-central Alberta to examine 1) whether patterns of habitat selection change with different scales of spatial extent, spatial resolution, habitat composition, temporal period, and between males and females during the active period, 2) habitat used for hibernation, and 3) factors influencing the timing and nature of movements to hibernation sites. I found that the abundance of the three amphibian species was best described at different spatial extents and was related to the biology of each species. Resource Selection Function (RSF) models, created using radio-telemetry data, indicated that habitat selection was scale-dependent for western toads; differences in selection were observed among study designs, study areas, time periods, and sexes. Predictive ability did not differ significantly among study designs. However, models that were created using a fine-grained map and home-range spatial extent generally produced models with greater predictive ability than models using a coarse-grained map or population-range extent. During the active season toads selected open habitat types such as wet shrub, disturbed grass, and crop/hay fields. Western toads hibernated terrestrially in pre-existing tunnels and the majority of toads hibernated in forest stands dominated by spruce. Toads used hibernation sites 1461936 m from breeding ponds and 68% of hibernacula were communal. Arrival at and entry into hibernation sites was influenced by temperature and/or day length; larger toads moved to hibernation sites later in the year. My research results can be used to identify and protect habitat for western toads in Canada. / Environmental Biology and Ecology

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