Biodiversity is a complex concept encapsulating the variation that occurs within and among levels of biological organization. It is positively linked to ecosystem persistence, adaptability, and function. Biodiversity loss, driven by global change and human activities, is one of the most prominent threats to ecosystems. Characterizing the variation of and processes driving biodiversity is a critical step in understanding the causes, consequences, and magnitude of biodiversity loss. However, characterizing biodiversity comprehensively requires understanding multiple dimensions, or types, of diversity, such as genetic, taxonomic, phylogenetic, and life history diversity, that encompass both ecological and evolutionary processes varying across space and time. In this dissertation, I investigate spatial and temporal variation in frog and toad (order Anura) biodiversity to understand the effects of how diversity is measured on biodiversity characterization and the underlying processes driving biodiversity. In my first chapter, I examined the spatial and temporal variation of genetic diversity and other population genetic metrics to understand the effects of multi-year sampling on population genetic inference in an anuran metapopulation (Arizona treefrog, Hyla (Dryophytes) wrightorum). I found that a single sample year captures global, but not local, population genetic dynamics, as there is considerable temporal variation in genetic metrics within individual populations. In my second chapter, I developed a tool to improve the characterization of anuran life history diversity using species traits. Traits are the measurable attributes of species, and a suite of species traits is used to distinguish ecological strategies found among species. I collated trait data from 411 primary and secondary sources for 106 anuran species found in the United States to develop an anuran traits database for use in conservation, management, and research. In my third chapter, I investigated spatial variation within and among taxonomic, phylogenetic, and life history anuran diversity in the United States and examined the abiotic relationships behind observed patterns. To do this, I developed species distribution models at a 1 km2 resolution for the majority of the native US anurans. I identified relationships among diversity metrics for improved, comprehensive biodiversity characterization and potential ecological and evolutionary processes underlying biodiversity. Spatial variation in multidimensional relationships highlights regional needs for multiple metrics of diversity to comprehensively characterize biodiversity. This spatial variation is driven by temperature, elevation, and water availability, likely related to the biological limits for anurans. Collectively, these chapters highlight the considerable variation that exists within and among species of a broad and diverse biological. Furthermore, these chapters call attention to the importance of measuring multiple biodiversity dimensions for effective conservation in a rapidly changing world. / Doctor of Philosophy / Biodiversity loss, from global change and human activities, is one of the biggest threats to the Earth's ecosystems. Biodiversity is the similarities and differences in organismal characteristics, such as their genetics, evolutionary history, and ecology. Biodiversity is often linked to how well an ecosystem will persist and adapt to global change. To understand the causes and consequences of biodiversity loss, it is important to first measure diversity and what shapes it. However, there are many types of diversity and ways to measure them, such as the number of species in a system, or species richness, the span of evolutionary lineages in a system, or phylogenetic diversity, the number of roles species fill in a system, or life history diversity, and the genetic relationships within individuals and populations, or genetic diversity. In this dissertation, I investigate how our understanding of biodiversity is affected by the ways it can be measured and the relationship among those metrics. To do this, I studied diversity in three ways for frogs and toads of the United States. First, I investigated whether sampling across multiple years is necessary to adequately characterize genetic diversity in a frog species (Arizona treefrog: Hyla (Dryophytes) wrightorum) with populations that fluctuate in size over time. Here, I found that multiple sample years are necessary to capture the genetic variation within individual populations over time, but unnecessary to capture the average genetic variation among all populations over space and time. Second, I developed a tool to improve our ability to measure anuran life history diversity using traits. Traits are measurable attributes of species, and multiple species traits can be used to define the role of a species in an ecosystem. I collected trait data from 411 sources for 106 frog and toad species found in the United States to develop a traits database for use in conservation, management, and research. Third, I investigated the similarities in multiple diversity metrics across the United States using species richness, phylogenetic diversity, and life history diversity. Species richness is highest in the eastern US, phylogenetic diversity is highest in the western US, and life history diversity is clustered around eastern US mountains. These regional relationships among metrics coincided with regional water availability, temperature, and elevation. These results collectively call attention to changes over space and time in frog and toad diversity and how the relationships within and among diversity types relate to our understanding of frog and toad biodiversity. Considering how, where, and when to measure biodiversity can lead to more effect biodiversity conservation in a rapidly changing world.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/115049 |
| Date | 15 May 2023 |
| Creators | Moore, Chloe Ellen |
| Contributors | Biological Sciences, Mims, Meryl C., Frimpong, Emmanuel A., Belden, Lisa K., Uyeda, Josef C. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf, application/pdf |
| Rights | Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International, http://creativecommons.org/licenses/by-nc-sa/4.0/ |
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