Quantitative And Landscape Approaches To Amphibian Conservation PDF Download

Amphibians are threatened world-wide, and due to the elusive, seasonal, and often nocturnal habits of adults, biological assessments of amphibian species are often best conducted via genetic analysis of easily-sampled pond-dwelling larvae. Genetic analysis of amphibian species can benefit their conservation in several ways, including identification of evolutionary lineages and subpopulations as fundamental units of conservation, genetic assessment of demography and diversity, and inference of patterns of gene flow among populations and how patterns are affected by environmental variation. In this dissertation I elucidated the evolutionary relationships and population genetic status of a threatened California amphibian (Spea hammondii) at multiple spatial scales using a combination of genetic, genomic, and environmental data. Chapter one utilized limited genetic data to determine phylogenetic relationships of Spea species and used environmental niche modeling to examine ecological differentiation between two allopatric lineages identified within S. hammondii. Chapter two took advantage of a newer genomic-scale dataset of thousands of SNP markers to look at fine-scale patterns of genetic variation among natural and artificial S. hammondii ponds in a highly urbanized region of Southern California. Chapter three also made use of thousands of markers to validate species-level relationships in Spea and used the added genomic resolution to examine relationships within and among genetic clusters and quantified the potential impacts of urbanization on functional genetic connectivity. Broadly, I found that the nominal taxon S. hammondii likely comprises two species. Populations within each species were highly differentiated from one another and had exceptionally low effective population sizes, such that each species lacks sufficient adaptive potential to thrive without intervention. Overall, this dissertation applied a suite of phylogenetic, population genomic, and landscape genomic tools to analyze patterns of genetic variation in S. hammondii to guide ongoing and future conservation efforts.