Biology Commons^™

Direct And Indirect Effects Of Invasive Cirsium Arvense On Pollination In Southern Appalachian Floral Communities, Jesse Daniels

Electronic Theses and Dissertations

Invasive plants can alter pollination dynamics in invaded communities by disrupting patterns of pollinator visitation, pollen transfer dynamics (conspecific [CP] and heterospecific [HP]), and reproductive success. The direction of invasive effects (competitive, neutral, and facilitative) may be partially determined by spatial scale and species’ floral traits. Here, we investigated pollinator visitation, CP and HP receipt, and pollen tube growth for species in a C. arvense present community and non-present community at two scales. At the community-level, the effect of C. arvense on pollinator visitation varied among species. Floral symmetry seemed to explain this variation. At the floral neighborhood-level, we found …

Indirect Food Web Interactions: Sea Otter Predation Linked To Invasion Success In A Marine Fouling Community, Maggie F. Jenkins

Master's Theses

Humans have caused grave ecological and economic damage worldwide through the introduction of invasive species. Understanding the factors that influence community susceptibility to invasion are important for controlling further spread of invasive species. Predators have been found to provide biotic resistance to invasion in both terrestrial and marine systems. However, predators can also have the opposite effect, and facilitate invasion. Therefore, recovery or expansion of native predators could facilitate the spread of invasive species. Needles et al. (2015) demonstrated that the threatened southern sea otter (Enhydra lutris nereis) facilitated the invasion of an exotic bryozoan, Watersipora subatra. …

Genetic Structure Of Invasive Baby’S Breath (Gypsophila Paniculata) Populations In A Michigan Dune System, Hailee B. Leimbach-Maus

Masters Theses

Invasive species can reduce biodiversity of a system by outcompeting native species for resources, changing the physical characteristics of a habitat, and altering natural disturbance regimes. Coastal sand dune ecosystems are dynamic with elevated levels of disturbance, and as such they are highly susceptible to plant invasions. The topography, geographic distribution of preferred habitat, and disturbance regime in an ecosystem can influence where an invasive plant becomes established, its dispersal patterns, and how densely it grows. One such invasion that is of major concern to the Great Lakes dune systems is baby’s breath (Gypsophila paniculata). The invasion of …

Characterization Of Urban Wetland Vegetation And Management Practices, Megan Anne Larson

Graduate Dissertations and Theses

Urban wetlands are important ecosystems that moderate flooding risks and improve water quality. Vegetation is a key component of urban wetlands; plants promote sedimentation, play critical roles in biogeochemical cycling, and provide food and habitats for other organisms. My research focuses on the standing vegetation and seed banks of urban wetland plant communities. Urban wetlands in south-central New York had a higher percent cover of invasive species in the standing vegetation and significantly lower species richness; however, native species were also common in urban flora. These sites had a high percentage of obligate wetland species, and most closely resembled emergent …

Direct And Indirect Controls On Bee Community Composition, Caroline Marie Devan

Dissertations

Bees are important pollinators, critical for the continued survival of plants in both natural and agricultural ecosystems. Diverse bee communities have been shown to increase richness in plant communities and plant reproduction depends upon bee community richness. Yet there is growing concern that pollinators, especially bees, are declining globally. This dissertation focuses on evaluating the mechanisms responsible for bee community composition in order to promote bee conservation in natural systems and their restoration in human-dominated urban and agricultural landscapes.

Bee populations are impacted directly by three things: floral resources, nesting resources and risk, primarily from natural enemies. Bees are indirectly …

Flames And Frogs – The Impact Of Environmental Disturbances On Host-Parasite Dynamics, Nicole Ortega

USF Tampa Graduate Theses and Dissertations

The successful completion of this work is dedicated first to my grandparents for having always shown their unwavering love and encouragement in my journeys (most of which they kindly and politely only pretended to understand) and for having also served as life-long role models who upheld an unparalleled work ethic. To many whom I consider to be my chosen family, especially Ann Williams and Brittany Sears, who kept me laughing, but more importantly, kept my crazy train from derailing during these tumultuous years. To Wayne Price and Tom Jackman, who fostered the success of my career and are the epitome …