Life Sciences Commons^™

Phenotypic Characterization Of Table Mountain (Pinus Pungens) And Pitch Pine (Pinus Rigida) Hybrids Along An Elevational Gradient In The Blue Ridge Mountains, Virginia, Alexander L. Brown

Theses and Dissertations

Hybridization has played a long-standing role in the evolution of both plant and animal species and allows for the sharing of genetic information between lineages. Here, potential hybridization of a species endemic to the Appalachian Mountains, Table Mountain pine (Pinus pungens), and pitch pine (Pinus rigida) was investigated along an elevational gradient, through the use of phenotypic measurements: cone length, cone width, and needle length. Phenotypes were used to identify hybrids in a three-tiered elevational sampling method at two sites in Shenandoah National Park with the use of linear discriminant analysis. It was found that hybridization …

Genetic Relatedness Can Alter The Strength Of Plant-Soil Feedbacks, Kelly M. Clark

Masters Theses

Intraspecific variation may play a key role in understanding the relationships between plants and their interactions with soil microbial communities. The effects that soil-microbes have on individuals can venerate variation across individuals in their responsiveness. I explored how relatedness alters plant-soil feedbacks in established Solidago altissima clones grown in a common garden. Seedlings of known parentage were inoculated with soils from the maternal, paternal, or unrelated clones and compared to autoclaved control inocula. I found that the soil inocula generated from S. altissima had an overall negative effect of seedling biomass. Furthermore, seedlings inoculated with maternal or paternal soils experienced …

Macroinvertebrate Responses To Hydrological Variation In Experimental Wetlands., Sergio A. Sabat-Bonilla

Electronic Theses and Dissertations

Predicted increases in the frequency of intense storms and periods of severe drought due to climate change represent a threat to wetland macroinvertebrate communities through alterations to the hydrological regime. I used experimental ponds to assess the effects of water permanence (i.e., duration of flooding) on the communities of aquatic macroinvertebrates. I predicted that permanent ponds would harbor higher diversity of longer-lived taxa whereas temporary ones will favor colonization by quick turnover, short-lived taxa and support lower consumer diversity. Results show differences in macroinvertebrate communities between permanent and temporary ponds can be mostly explained by hydrology and the amount of …

Applications Of Machine Learning In Microbial Forensics, Ryan B. Ghannam

Dissertations, Master's Theses and Master's Reports

Microbial ecosystems are complex, with hundreds of members interacting with each other and the environment. The intricate and hidden behaviors underlying these interactions make research questions challenging – but can be better understood through machine learning. However, most machine learning that is used in microbiome work is a black box form of investigation, where accurate predictions can be made, but the inner logic behind what is driving prediction is hidden behind nontransparent layers of complexity.

Accordingly, the goal of this dissertation is to provide an interpretable and in-depth machine learning approach to investigate microbial biogeography and to use micro-organisms as …