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Invasive Plant (Alliaria Petiolata; Garlic Mustard) Homogenizes Fungal Communtiy Composition And Increases Fungal Richness, Mark Anthony

Master's Theses and Capstones

Non-native invasive plants can disrupt native plant communities and soil function (e.g., C and N cycling), but few studies have examined how soil microbial community structure differs in association with invasion. This work focused on Alliaria petiolata (garlic mustard), a non-mycorrhizal Brassicaceae that can displace native plants and reduce aboveground diversity. Garlic mustard produces toxic phytochemicals that can suppress mycorrhizal fungi, but we currently do not know if garlic mustard invasion affects the general fungal community, including specific mycorrhizal fungi, saprotrophic fungi, and plant pathogens and parasites. The objective of this work was to compare uninvaded and invaded soils from …

Establishment Of The Multicolored Asian Lady Beetle, Harmonia Axyridis, As A Model System For The Evolution Of Phenotypic Variation, Lindsay Havens

Master's Theses and Capstones

The mechanisms behind the evolution and maintenance of striking visual phenotypes are as varied as the species that display these phenotypes. Multiple study systems have been well characterized and provide critical information about the evolution of these traits. However, new study systems in which the phenotype of interest can be easily manipulated and quantified are essential to answer many questions about the functionality of core evolutionary processes. One such model is elytral spot number of the multicolored Asian lady beetle, Harmonia axyridis (Chapter 1). I describe Harmonia axyridis as a potential novel model species for examining extreme phenotypic evolution. To …

Genetic And Evolutionary Analysis Of Plant Replication Protein A 1 (Rpa1), Behailu Birhanu Aklilu

Doctoral Dissertations

Challenging human health issues include treatments for genetic diseases and providing improved agricultural crop output to feed the growing world population. The project described here, which focuses on how cells respond to chromosomal (genomic) damage, has significant implications in each example. In humans, accumulation of DNA damage induced mutations can result in genetic diseases such as cancer, and in plants can similarly result in genome instability, reducing productivity. Organisms from human to plants have conserved mechanisms to counteract DNA damage. However, detailed genetic and biochemical information on plant DNA repair systems is still limited. The goal of this dissertation was …

Hybrid Zone Dynamics Between Saltmarsh (Ammodramus Caudacutus) And Nelson's (Ammodramus Nelsoni) Sparrows, Jennifer Walsh

Doctoral Dissertations

Hybrid zones in nature have long been equated to “windows on the evolutionary process” providing unique environments to understand patterns of gene flow and introgression and the role of these mechanisms in maintaining biodiversity. Ongoing hybridization and introgression can lead to a number of conservation and evolutionary outcomes; as such, identifying the role of introgression in natural populations can provide new insights into species interactions while contributing to our understanding of evolutionary theory.

The research presented below characterizes hybrid zone dynamics between two tidal marsh endemics – the Saltmarsh (Ammodramus caudacutus) and Nelson’s (Ammodramus nelsoni) sparrow. Both species co-inhabit salt …

Genomic Resource Development And Candidate Gene Evaluation In Fragaria Vesca (L.), Melanie Eileen Shields

Doctoral Dissertations

The wild strawberry Fragaria vesca (L. Rosaceae) is an important diploid model plant system for the study of processes associated with crop production, plant physiology, and cultivar development of the octoploid cultivated strawberry (F. ×ananassa), an economically important crop plant. A fosmid clone library developed from F. vesca ssp. americana ‘Pawtuckaway’, and a mapping population of 96 F2 progeny (YPF2) resulting from a cross of F. vesca ssp. semperflorens “Yellow Wonder’ with F. vesca ssp. americana ‘Pawtuckaway’, were employed to further develop genetic and genomic resources and advance the search for the molecular identity of the classically defined fruit color …

A Landscape Genetics Approach For Comparing Connectivity Across The Range Of The New England Cottontail, Katrina Papanastassiou

Master's Theses and Capstones

Habitat connectivity is vital for dispersal and metapopulation persistence. Land use change and landscape modification alter the distribution and availability of habitat, thereby altering connectivity and impeding organisms’ dispersal abilities. Reduction of connectivity is a concern for the New England cottontail (Sylvilagus transitionalis), a species of high conservation priority that has experienced a dramatic decline of its required shrubland habitat. To better understand New England cottontail connectivity, I used a landscape genetics approach to assess the impact of landscape features on cottontail dispersal in two geographically isolated study areas, one in southern Maine-seacoast New Hampshire and the other in eastern …