Life Sciences Commons^™

Population Trends And Trophic Ecology Of The Invasive Peacock Eel (Macrognathus Siamensis) In The Florida Everglades, Grace Kahmann

Electronic Theses and Dissertations

Invasive species threaten the ecological integrity of ecosystems worldwide, including the Florida Coastal Everglades. This study investigated the ecological role of the peacock eel (Macrognathus siamensis) within this ecosystem, emphasizing its population trends and the environmental factors that affect its population performance, and the potential for interactions with native fish assemblages and coastal food webs. I used 19 years of electrofishing data to investigate the population trends of peacock eels at the marsh-mangrove ecotone of the Shark River Estuary, Everglades National Park (Florida, USA). I found that peacock eel populations have increased since their first detection in 2002, and their …

Assessing The Appropriateness Of Free-Roaming Cat Management Strategies Based On Resident Perspectives In A Small Pennsylvania Municipality, Brianna Marks

Electronic Theses and Dissertations

The popularity and mismanagement of free-roaming cats has resulted in invasive populations responsible for over-predation of birds and small mammals and increased disease transmission to humans and animals (Bies, 2014; Crowley et al., 2020). Management effectiveness fluctuates between communities due to varying opinions of free-roaming cats by governments and the public, which can influence management development and success (Deak et al., 2019). This research assesses the relationship between community perspectives of free-roaming cats and management. A survey of residents in a small Pennsylvania municipality was conducted with questions pertaining to free-roaming cats and management preferences in the community. Over 50% …

Dna Methylation And The Response To Infection In Introduced House Sparrows, Melanie Gibson

Electronic Theses and Dissertations

Epigenetics is the study of molecular modification of a genome without changing its base pairs. The most studied type of epigenetic mechanism is DNA methylation, which is capable of turning a gene “on” or “off.” Epigenetic potential is the capacity to which an individual can have methylation on its genome. The more CpGs available, the greater the epigenetic potential. In invasive species, genetic variation has been observed to be paradoxical: not much of it exists on a genomic level, but epigenetically, phenotypic variation can occur. The focus on shift in gene expression in this study is on Toll-Like Receptor 4 …

Behavior And Chemical Signals As Markers Of Colony Identification In Argentine Ants (Linepithema Humile), Stephanie A. Rohrbach

Electronic Theses and Dissertations

Argentine ants, Linepithema humile, are a highly successful invasive species around the globe and are especially prominent in states such as California and the southeastern United States. L.humile have a unique form of unicoloniality, called “supercolonies”. L. humile can detect colonymates through scent markers in their outer cuticle. With these chemical markers, ants will exhibit high aggression if they smell different from one another. In our study, we performed aggression assays among ten different nest sites and analyzed their CHCs through gas chromatography mass spectrometry, or GC-MS, analysis. For our behavior results, while within-nest interactions displayed low aggression as …

Understanding Patterns And Functional Impacts Of An Invasive Tree And Its Biological Control In A Riparian System, Annie L. Henry

Electronic Theses and Dissertations

Invasive species have become an inextricable part of the landscape, particularly in riparian plant communities, and removal is often a key component of restoration programs. Biological control (biocontrol) is a method of removal that is often both efficient and effective. However, the impact of biocontrol on target species and indirect effects from invasive species removal can be hard to predict. While monitoring the impact of invasive species removal usually involves some species-based assessment such as changes in diversity, historically dominant species or native species, these strategies do not typically provide insight into the mechanisms underlying plant community response to removal. …

An Invasive Species As A Threat To Native Biodiversity: Larval Competition Between Native Anurans And An Invasive Treefrog, Mckenzie Wasley

Electronic Theses and Dissertations

Cuban Treefrogs (Osteopilus septentrionalis) are established in Florida and Louisiana and have invasive potential further westward, possibly impacting native anurans at multiple life stages. In anurans, competition at the larval stage can decrease adult fitness through slower development and smaller size at metamorphosis, ultimately decreasing recruitment rates. To examine the potential impacts of O. septentrionalis at the larval life-history stage, I quantified activity levels and growth of their tadpoles and those of two anurans native to eastern Texas: Green Treefrogs (Hyla cinerea) and Gulf Coast Toads (Incilius nebulifer). Tadpoles of the three species were …

Stoichiometric Homeostasis In Two Native And Two Invasive South Dakotan Grasses, Joshua Thonas Harvey

Electronic Theses and Dissertations

Increased nutrient availability has been widely linked to the success of invasive plants, however a general mechanism explaining these observations is lacking. Stoichiometric homeostasis (H), which is the regulation of internal nutrient concentrations, has been used to explain changes in plant community diversity under alterations in nutrient availability. One hypothesis holds that plants with high regulation (larger H) decrease in abundance in nutrient enriched conditions but are stable in nutrient deficient and drought conditions, likely due to extensive root systems. Additionally, plants with low regulation (lower H) increase in abundance under nutrient enriched conditions but are sensitive to drought …

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 …

Phenotypic Plasticity Of Native And Invasive Cool-Season Grasses In Response To Frequency Of Moisture Availability, Ming-Yu Stephens

Electronic Theses and Dissertations

Phenotypic plasticity, the ability of an individual to alter its growth in response to environmental conditions, is an attribute that is considered a likely invader attribute, as it provides the opportunity to expand its ecological niche breadth. Adaptive phenotypic plasticity can affect not only the ability to establish in a new environment, but also the ability to outperform the existing vegetation over time. Bromus inermis (smooth brome) and Poa pratensis (Kentucky bluegrass) are invasive species in tall- and mixed-grass prairie ecosystems. The objectives of this two-part study were to quantify the adaptive plasticity of biomass accumulation and tiller production in …

Assessing The Genetic Status And Factors Leading To The Decline Of The Roanoke Bass (Ambloplites Cavifrons), Jackman C. Eschenroeder

Electronic Theses and Dissertations

Although numerous factors have led to the staggering declines in freshwater biodiversity throughout the United States and the world, habitat alteration and introduced species pose some of the greatest challenges to conservation efforts. Learning more about how these two factors lead to the decline of an endemic organism could help prevent the future loss of unique species and the premature conclusion of evolutionary trajectories. Roanoke bass (Ambloplites cavifrons) is a sport fish endemic to portions of the Roanoke, Chowan, Tar, and Neuse river basins of North Carolina and Virginia. This species has been in decline for many years, …

The Influence Of The Invasive Chinese Tallow (Triadica Sebifera) Leaf Litter On Aquatic Chemistry And Microbial Community Composition, Raymond D. Montez

Electronic Theses and Dissertations

Global climate change and anthropogenic activity have facilitated the movement and invasive potential of nonnative plants in native environments. These invasions can have negative effects on ecosystem diversity and function. The nonnative and invasive plant, Chinese Tallow (Triadica sebifera), has already invaded much of the south eastern US where it is outcompeting native tree species and changing ecosystem diversity in a variety of habitats. Leaf litter from the Chinese tallow has been shown cause changes in dissolved oxygen and pH in the aquatic environment. Turbidity is also affected when Chinese tallow litter is present in water. A series of …

Effects Of Invasive Shrub Honeysuckle (Lonicera Maackii) And Forest Composition On Bird Communities In Woodland Stands., Katie Rae Lynch

Electronic Theses and Dissertations

Invasive species pose a threat to aquatic and terrestrial ecosystems by decreasing biodiversity (Didham et al. 2005). Amur bush honeysuckle (Lonicera maackii) has typically reduced native plant diversity and altered animal communities by influencing animal abundance and activity (Collier and Vankat 2002). This study was intended to determine whether honeysuckle density or other characteristics of forested stands influence avian diversity, whether impacts are seasonally dependent, and whether correlations exist between attributes of forested stands and honeysuckle density. In order to test the hypotheses, thirteen forest stands within the Louisville Metropolitan Area were selected. They had similar tree composition …

Woody Plant Communities Of Three Urban Wetlands And The Success Of An Invasive Shrub (Lonicera Maackii) Over Natural And Experimental Flooding Gradients., Meghan Rhea Langley

Electronic Theses and Dissertations

Globally, wetlands are known for providing important ecosystem services that enhance the quality of human life and regulating global biogeochemical cycles. Despite the wide recognition of their value, temperate forested wetlands are the least protected type of ecosystem world-wide, and are threatened by human activities such as logging and development. The ecology of forested wetlands remaining in urbanized areas is impacted by a multitude of anthropogenic threats, including fragmentation (which decreases the amount of interior habitat and increases edge habitat), hydrologic modification (ditching and draining of wetlands) and the incursion of invasive species (which are frequently introduced by human activities). …

Plant Community Responses To Invasive Shrub And Vine Removal In An Urban Park Woodland., Eric Richard Moore

Electronic Theses and Dissertations

Counter to what some people think, urban areas can be biodiversity hotspots. Maintaining this biodiversity can be challenging, since exotic shrubs and vines block sunlight and threaten native plant regeneration. Since 2007, the Louisville Olmsted Parks Conservancy (LOPC) has spent $2 million on invasive plant management in Cherokee Park. Before the project began, long-term transects were established by the LOPC to collect baseline presence/absence data on 11 invasive plant species. In 2014, I revisited these transects and documented presence/absence data on the entire plant community. I found that four species (garlic mustard, winter creeper, Japanese honeysuckle, and English ivy) have …

Soil Bacterial Structure And Function Associated With The Invasive Grass Microsteguim Vimineum And Two Native Grasses, Jennifer Kay Bell

Electronic Theses and Dissertations

Soil microorganisms play vital roles in biogeochemical cycles and are necessary for maintaining soil health. An invasive plant that alters the structure and function of the soil microbial assemblage could gain an advantage over native plants, enhancing its ability to invade new habitats, alter ecosystem function, and hinder efforts to reestablish native populations. Assays of enzyme activity and next generation sequencing of bacterial 16S rRNA genes were used to assess the soil microbial function and community structure associated with the invasive grass, Microstegium vimineum and two co-occurring native grasses (Dichanthelium boscii and Chasmanthium laxum). Significantly lower enzyme activity was found …

The Effects Of Non-Native Species On Two Life-Stages Of The Eastern Oyster Crassostrea Virginica, Wei Yuan

Electronic Theses and Dissertations

Since their recent introductions into Florida waters, three nonnative species [Perna viridis Linnaeus, 1758 (Asian green mussel), Mytella charruana d'Orbigny, 1846 (charru mussel) and Megabalanus coccopoma Darwin, 1854 (pink titan acorn barnacle)] have expanded both north and south along the Atlantic coast. Very little research has been done to understand how these nonnative species interact with the native eastern oyster (Crassostrea virginica Gmelin, 1791), which is a keystone species that provides important ecological services and economic benefits. To test the potential effects of P. viridis, M. charruana and M. coccopoma on C. virginica, I addressed the following questions: 1a) Does …

Evaluation Of The Three-Dimensional Patterns And Ecological Impacts Of The Invasive Old World Climbing Fern (Lygodium Microphyllum), Alexis Maldonado

Electronic Theses and Dissertations

Invasion by non-native species has had significant ecological and economic impacts on a global scale. In the state of Florida, Old World climbing fern (Lygodium microphyllum) is an invasive plant listed by FLEPPC as a category one invader with significant ecological impacts that threaten native plant diversity. This species relies on existing vegetative structures for support to climb into the forest canopy and forms dense mats that cover tree crowns. This subsequently affects the resources available to other species present. Quantifying the structural changes due to the presence of this species has proved logistically difficult, especially on a large spatial …

The Next "Killer" Algae? Assessing And Mitigating Invasion Risk For Aquarium Strains Of The Marine Macroalgal Genus Chaetomorpha, Rachel Odom

Electronic Theses and Dissertations

Biological invasions threaten the ecological integrity of natural ecosystems. Anthropogenic introductions of non-native species can displace native flora and fauna, altering community compositions and disrupting ecosystem services. One often-overlooked vector for such introductions is the release of aquarium organisms into aquatic ecosystems. Following detrimental aquarium-release invasions by the "killer alga" Caulerpa taxifolia, aquarium hobbyists and professions began promoting the use of other genera of macroalgae as "safe" alternatives. The most popular of these marine aquarium macroalgae, the genus Chaetomorpha, is analyzed here for invasion risk. Mitigation strategies are also evaluated. I found that the propensity for reproduction by vegetative fragmentation …

Limnological And Landscape Factors Affecting Use Of Manufactured Ponds By The Invasive Cuban Treefrog (Osteopilus Septentrionalis), Terina Nusinov

Electronic Theses and Dissertations

Exotic amphibians are often detrimental to native biotas. In Florida, the exotic Cuban Treefrog (Osteopilus septentrionalis) eats native frogs and may outcompete them for resources. Cuban Treefrogs thrive in disturbed areas and around buildings, and often breed in manufactured wetlands such as retention ponds and borrow pits. This study identified limnological, landscape, and biotic characteristics that discouraged pond use by Cuban Treefrogs and promoted use by native amphibian species. I sampled natural and manufactured ponds in Orange County, Florida, for one year, using standard methods to estimate the species richness and relative abundance of amphibians and their potential fish and …

Is The Exotic Brazilian Pepper, Schinus Terebinthifolius, A Threat To Mangrove Ecosystems In Florida?, Melinda Donnelly

Electronic Theses and Dissertations

Mangrove ecosystems are critical to Florida, providing economic resources to humans, and untold ecological resources to estuarine organisms. In Florida's estuaries, mangrove ecosystems have suffered significant losses due to natural and human disturbances; these disturbances potentially leave mangrove communities vulnerable to invasion by the opportunistic exotic, Schinus terebinthifolius (Brazilian pepper). Prior experiments have suggested that Schinus terebinthifolius is unable to survive under marine conditions and poses no long term threat to mangrove systems. However, this contradicts field observations where Schinus terebinthifolius was found growing in the intertidal zone of Mosquito Lagoon alongside three native species of mangroves, Rhizophora mangle, Avicennia …

Fire, Soil, Native Species And Control Of Phalaris Arundinacea In A Wetland Recovery Project., Richard Douglas Foster

Electronic Theses and Dissertations

Southern Appalachian Phalaris arundinacea control was investigated by: 1) correlating cover and species richness with soil characteristics across transects; 2) burning and herbicide use to determine conditions facilitating native plant establishment; and 3) hemi-parasitic Pedicularis lanceolata tested as a biological control.

Phalaris cover was correlated with subsoil consolidation; areas without Phalaris had consolidated subsoil while Phalaris at >50% cover established on loose soil. Phalaris cover inhibited species richness (r²=0.78). No soil characteristic predicted species richness.

Herbicide reduced Phalaris cover and aerial biomass by 23% and 63% respectively, compared to controls. Burning was ineffective. Two summers after herbicide Phalaris …

The Fresh-Water Fishes Of Maine, Flavia Lucile Richardson

Electronic Theses and Dissertations

The purpose of this investigation is to determine the present status of the fish fauna of Maine. Data assembled during the course of this study includes descriptions of native and introduced species, records concerning their present distribution, and the extent of the official introduction of non-indigenous species. From this material may be derived conclusions respecting the survival of the introduced species and the probable capacity of the native species to successfully compete with them. Through the use of descriptive material assembled during the investigation of species it has been possible to construct a key as an aid in identifying any …