Biology Commons^™

Legacy Habitat Suitability Of Eastern Oysters (Crassostrea Virginica) In Louisiana: A Prelude To Mississippi River Delta Freshwater Diversions, Tasia Mv Denapolis

University of New Orleans Theses and Dissertations

The Louisiana oyster industry is greatly impacted by freshwater and sediment diversions that are part of the effort to restore the state’s coastline. A habitat suitability index (HSI) proposes species-habitat relationships that can be instrumental in creating impact assessments and suitability predictions for management as new diversions are implemented. An oyster (Crassostrea virginica) HSI was developed using three variables crucial to oyster sustainability: average annual salinity, minimum monthly salinity, and average salinity during the spawning season. These Legacy HSI visualizations show annual fluctuations in the distribution of zones suitable for oyster cultivation prior to proposed diversions in Pontchartrain …

Plant Stimuli-Responsive Biodegradable Polymers For The Use In Timed Release Fertilizer Coatings, Spencer Heuchan

Electronic Thesis and Dissertation Repository

The use of nitrogen-based fertilizers continues to accelerate with human population growth and increases in global food requirements. Enhanced efficiency fertilizers (EEFs) have been developed to improve the synchronization between nutrient supply and crop nutrient demand. However, many of the current controlled release fertilizers are coated with non-degradable polymers that contribute to accumulation of microplastics within ecosystems. This thesis describes research towards the development of a new class of fertilizer coatings using a self-immolative polymer known as poly (ethyl glyoxylate) (PEtG). PEtG itself does not have suitable properties to produce a viable coating but once blended with another degradable polyester …

Physiological Responses Of The State – Listed Texas Pigtoe To Environmental Stress, Sara M. Rumbelow

Biology Theses

Systematic habitat destruction over the last 100 years combined with major anthropogenic stressors such as aquatic contaminants, exotic species, and economic endeavors are driving the decline in freshwater unionid species diversity. Two hundred fifty-seven individual adult Texas pigtoe (Fusconaia askewi) mussels (mean length, mm ± 1 SD; 58.7 ± 13.8) were collected from the upper Sabine river near Hawkins, Texas and taken to the University of Texas at Tyler to evaluate three factors likely impacting mussels in East Texas: siltation (a surrogate for bank erosion), elevated temperature and nitrogen. The impact of siltation was evaluated by burying mussels …

Genetic Diversity In An Invasive Clonal Plant? A Historical And Contemporary Perspective, Elliot D. Weidow

University of New Orleans Theses and Dissertations

Introduced populations of Eichhornia crassipes (Pontederiaceae) possess extremely low levels of genetic diversity due to severe bottleneck events and clonal reproduction. While populations elsewhere have been well studied, North American populations of E. crassipes remain understudied. We used Amplified Fragment Length Polymorphism markers to assess genetic diversity and population structure in North American E. crassipes populations. Patterns of diversity over the past fifty years were analyzed using herbarium specimens. Furthermore, we sampled populations across the Gulf Coast of the United States throughout a year to determine contemporary genetic diversity and assess potential seasonal effects. Genetic diversity was found to be …

Bubble Stream Production By Belugas (Delphinapterus Leucas), Megan Slack

Theses

Bubble stream production in belugas has been poorly characterized and its function is not well understood. I examined behavioral states when producing bubble streams (“bubbling”), and when bubbling calls, to determine whether bubbling was significantly associated with a particular call category or behavioral state. Using 19 hours of video and audio recordings collected over a two-day period, I quantified bubble streams of a 4-month old calf and an unrelated adult female housed together. Based on the overall activity budgets and pool of vocalizations for both animals, I calculated the expected counts of bubble streams with and without vocalizations, assuming that …

Coastal Wetland Dynamics Under Sea-Level Rise And Wetland Restoration In The Northern Gulf Of Mexico Using Bayesian Multilevel Models And A Web Tool, Tyler Hardy

Master's Theses

There is currently a lack of modeling framework to predict how relative sea-level rise (SLR), combined with restoration activities, affects landscapes of coastal wetlands with uncertainties accounted for at the entire northern Gulf of Mexico (NGOM). I developed such a modeling framework – Bayesian multi-level models to study the spatial pattern of wetland loss in the NGOM, driven by relative RSLR, vegetation productivity, tidal range, coastal slope, and wave height – all interacting with river-borne sediment availability, indicated by hydrological regimes. These interactions have not been comprehensively investigated before. I further modified this model to assess the efficacy of restoration …

Macrophytes And Atrazine In Ponds Of Southwest Missouri, Christine Michelle Cornish

MSU Graduate Theses

Wetlands are often the ultimate destination of agrochemicals. The increased use of these pollutants has resulted in their increased transport, via runoff and spray drift, into wetlands. Atrazine, a commonly used herbicide, has been detected in surface water, groundwater, soil, and sediment, and has shown to have adverse impacts on aquatic biota, such as fish and amphibians. Few studies have reported on the relationships between atrazine and macrophytes. I measured atrazine concentrations in surface sediments in agricultural, conservation, and golf course ponds of southwest Missouri, and investigated how those concentrations might be related to macrophyte communities, and pond environmental characteristics. …

Long-Term Trends Of Stream Fish Community Assemblages In Southern Missouri With Contemporary Land Use Impacts, Stephanie Marie Sickler

MSU Graduate Theses

Stream fish communities in the Ozarks are structured via a number of different mechanisms, including basin, stream size, and human land use. The purpose of this study was to understand the structuring mechanisms of stream fish communities in southern Missouri. I compiled 48 years of historical fish collections performed by the Ichthyology class at Missouri State University consisting of 140 sites. I resampled 45 of these sites in summer of 2016. First, I tested whether communities are different between basins and stream size. Next, I tested associations of land use at three spatial scales to local fish communities. Last, I …

Successional Processes In The Benthic Invertebrate Communities At Gray’S Reef National Marine Sanctuary, Alexis A. Bivens

Honors College Theses

While the process of community development has been studied in terrestrial habitats since the turn of the 20th century, similar information is not as readily available in marine systems. Understanding patterns of community development is essential to predicting recovery potential and to designing effective marine protected areas. In the South Atlantic Bight, invertebrate communities on hard substrata can differ significantly from one rocky outcrop to another, but the factors driving these differences are not well understood. I documented the initial development of the benthic invertebrate community at Gray’s Reef National Marine Sanctuary (GRNMS) to address the prediction that this system …

Radical Social Ecology As Deep Pragmatism: A Call To The Abolition Of Systemic Dissonance And The Minimization Of Entropic Chaos, Arielle Brender

Student Theses 2015-Present

This paper aims to shed light on the dissonance caused by the superimposition of Dominant Human Systems on Natural Systems. I highlight the synthetic nature of Dominant Human Systems as egoic and linguistic phenomenon manufactured by a mere portion of the human population, which renders them inherently oppressive unto peoples and landscapes whose wisdom were barred from the design process. In pursuing a radical pragmatic approach to mending the simultaneous oppression and destruction of the human being and the earth, I highlight the necessity of minimizing entropic chaos caused by excess energy expenditure, an essential feature of systems that aim …

Habitat Associations And Detectability Of Three Unionid Species Along The Upper Sabine River In East Texas, Jared Dickson

Biology Theses

East Texas contains the highest diversity of mussels in the state. Of the 37 species in East Texas, six are listed by the state as threatened and three have been proposed for listing as threatened or endangered under the U.S. Endangered Species Act. Although diverse, mussel populations are declining and few studies exist that establish habitat relationships identifying determinants of mussel distributions in the upper Sabine River. I explored potential habitat preferences of three state listed species using an occupancy modeling approach, including the: Texas Pigtoe, Fusconaia askewi, Sandbank Pocketbook, Lampsilis satura, and Texas Heelsplitter, Potamilus amphicaenus. …

Reproductive Effort And Lipid Dynamics Of The Emerald Shiner (Notropis Atherinoides) In The Upper Niagara River, New York, Christopher A. Osborne

Biology Theses

Life history theory predicts that reproductive characteristics of organisms will be shaped by biotic and abiotic factors to maximize their overall fitness. In this study, I investigated how growth, reproductive effort, and lipid dynamics vary ontogenetically and seasonally for emerald shiners (Notropis atherinoides) in the upper Niagara River. Growth rates were highest in age 2 shiners and lower in age 1 and age 3 individuals. Evidence of reproduction was found beginning at age 1, and reproductive investment as measured by ovarian lipid content was lowest in age 1 and age 2 individuals and greatest in age 3 fish. …

The Role And Contribution Of Saprotrophic Fungi During Standing Litter Decomposition Of Two Perennial Grass Species, Schizachyrium Scoparium And Schizachyrium Tenerum, Matthew Lodato

Master's Theses

In terrestrial ecosystems, most of the plant biomass produced enters the detrital pool, where microbial decomposers colonize, enzymatically degrade, and assimilate plant litter carbon and nutrients in amounts sufficient to bring about the decomposition of plant litter. Here, I estimated the biomass and production of fungi and microbial respiration associated with decaying Schizachyrium scoparium and Schizachyrium tenerum leaf litter, and constructed a partial organic matter budget estimating C flow into and through fungal decomposers. Significant losses in S. scoparium (57%) and S. tenerum (68%) leaf mass was observed during litter decomposition along with concomitant increases in fungal biomass, which reached …

Detrital Protein Contributes To Oyster Nutrition And Growth In The Damariscotta Estuary, Maine, Usa, Cheyenne M. Adams

Electronic Theses and Dissertations

Oyster aquaculture is an expanding industry that relies on identifying and utilizing natural estuarine conditions for the economically viable production of a filter-feeding crop. The eastern oyster, Crassostrea virginica, is the principal species currently cultured in Maine. In addition to preferentially consumed phytoplankton, various detrital complexes (non-algal and/or non-living organic matter) may provide some nutrition to C. virginica between times of phytoplankton abundance. Here I investigated the importance of detrital proteins in supporting the growth of oysters cultured in the upper Damariscotta Estuary. Oyster aquaculture in this area is highly successful and previous reports indicate that labile detrital protein …

Evaluating In Situ Grazing Patterns Of Lytechinus Variegatus And Their Effects On Seagrass Beds Of Thalassia Testudinum, Adrianna Parson

Master of Science in Integrative Biology Theses

The sea urchin Lytechinus variegatus is a known grazer of the seagrass Thalassia testudinum, and has been known to denude vast stands of seagrass beds at high densities. Outside of these denudation events, the effects of sea urchins on seagrass are poorly understood. This study examines the effects of L. variegatus on T. testudinum in situ, to understand how sea urchins are affecting seagrasses in situ. Results indicate that urchins were found in the offshore portion of the seagrass bed at densities up to 4 urchins/m². Changes in temperature and sediment size in the bay indicate …

Wildlife Use Of Vernal Pools In An Urbanizing Landscape With A Focus On Population Vitality Of Vernal Pool-Breeding Amphibians, Carly Eakin

Electronic Theses and Dissertations

Vernal pools in the northeastern United States provide essential habitat for pool-breeding amphibians and provide resources for other forest-dwelling wildlife. These pools and pool-breeding amphibians in particular are threatened by land conversion associated with urbanization and urban-associated factors. The responses of these amphibians and of birds and mammals using vernal pools to intermediate levels of urban development are largely unknown. I used field observations and lab experiments to study the amphibians, birds, and mammals associated with vernal pools along an urban development gradient in greater Bangor, Maine.

In Chapter 1, I examined bird and mammal use and assemblage composition at …

Microbial Community Response To Light And Heavy Crude Oil In Freshwater Systems, Timothy M. Butler

Dissertations, Master's Theses and Master's Reports

With increased demand for oil, there is an increased risk for oil spills in many environments. A number of pipelines transport oil near or across freshwater systems including the Great Lakes. Microbes are capable of breaking down oil and have thus been proposed as tools for oil spill response through bioremediation. There is a need to understand the microbial response to diverse oil types in freshwater environments due to the lack of research into this topic. This study’s main objectives are to understand how the freshwater microbial communities respond to oil, and how the bacterial communities may respond to different …

Ms Environmental Biology Capstone Project, Meghan Mcgill

Regis University Student Publications (comprehensive collection)

This study aims to provide a deeper understanding of the role of competition in food webs, and more specifically, in trophic cascades induced by biodiversity loss. Trophic cascades are food web disturbances that result from the removal of an important species, often a predator, and lead to dramatic changes in herbivore and plant populations. It is critical to understand the mechanisms that drive and mitigate trophic cascades, because global biodiversity loss is increasing. Previous research suggests that biodiversity, specifically intraguild biodiversity with members in the same trophic level, is an important factor in reducing the negative effects of trophic cascades. …

Vegetation Community Development After Dam Removal On The Elwha River, Olivia A. Morgan

EWU Masters Thesis Collection

The Elwha River is the site of the largest dam removal project in the world to date and serves as a case study for the ecological effects of large dam removal. The 2012-2014 removal of two dams on the Elwha River exposed a cumulative 2.76 km2 of previously inundated surfaces. Environmental conditions including sediment texture and nutrients, slope-aspect, dispersal distance from the river and mature forest, disturbance, and elevation vary widely across the reservoir surfaces, causing significant variation in the plant community. The first objective of my study is to continue a long-term study of the passively restored vegetation community …

Ms Environmental Biology Capstone Project, Annamaria Marcel

Regis University Student Publications (comprehensive collection)

Due to the worldwide decline of biodiversity, protected nature reserves are necessary for species facing extinction. Many frog species have been experiencing rapid population decline and extinction due to the threat of the fungus Batrachochytrium dendrobatidis (Bd), which inflicts the highly transmittable and deadly disease chytridiomycosis. Chytridiomycosis causes increased skin tissue growth which disrupts respiration and the maintenance of water balance, which can ultimately lead to death. Certain ecological and geographical characteristics have been studied in order to assess their influence on Bd’s prevalence. Specifically, it is hypothesized that high elevations, lotic habitats, and low species richness have a positive …

Comparison Of Three Benthic Macroinvertebrate Passive Sampling Devices For Non-Wadeable Streams, Kelsey A. Laymon

Electronic Theses and Dissertations

Rivers and streams provide essential ecosystem services to the degree that the monitoring and maintenance of these systems becomes imperative. Biomonitoring provides managers and policymakers with the tools to make informed decisions, and macroinvertebrates are often the object of biomonitoring because they are ubiquitous in most systems and are known to be good indicators of water quality. However, methods for sampling macroinvertebrates in non-wadeable streams (i.e., large rivers) have not been standardized across states and regions and an established method for macroinvertebrate biomonitoring in large rivers of Georgia is not currently available. My study compared macroinvertebrates collected with three types …

Predictors Of Fish Assemblage Structure And Dynamics In Atlantic Coastal Plain Streams, Rebecca Scott

Electronic Theses and Dissertations

Effective management of freshwater fishes requires a mechanistic understanding of the drivers of assemblage composition; in other words, what determines who is where and when. Stream fish assemblages are potentially influenced by environmental factors that act on multiple spatiotemporal scales, but the relative influence of these drivers may vary between geophysically distinct regions. This study sought to determine the patterns and drivers of fish taxonomic and functional assemblage composition in the coastal plain, a region possessing unique hydrologies, faunas, and physiochemical conditions. I addressed this goal using two complementary chapters, both of which utilized environmental and biotic data collected from …

Oyster Reef Restoration: Impacts On Infaunal Communities In A Shallow Water Estuary, Katherine P. Harris

Honors Undergraduate Theses

Oyster reefs are important estuarine ecosystems that provide habitat to many species including threatened and endangered wading birds and commercially important fishes and crabs. Infaunal organisms (i.e. small, aquatic animals that burrow in the sediment) are also supported by oyster reef habitats. Infaunal organisms are critical to marine food webs and are consumed by many important species that inhabit coastal estuaries. However, over the past century 85% of shellfish reef habitats have been lost, making restoration of these areas vital. Due to their important role in coastal food webs, infauna is hypothesized to be a strong indicator of habitat productivity …

Dna Extraction And Microsatellite Amplification Of Daphnia Pulicaria Resting Eggs: Analysis Of Allele Frequencies Through Time, Anna Ries

Departmental Honors Projects

A paleoecological approach allows for the study of genetic change in populations over longer periods of time than would be possible if one were sampling populations from year to year. Daphnia and other cladoceran zooplankton are amenable to this type of study because they produce diapausing embryos (ephippial eggs) when they sexually reproduce, and these resting eggs can remain viable for decades to centuries in lake sediments. This study uses paleoecological methods as well as a new methodology for ephippial DNA extraction and amplification to assay for genetic variation in ephippial eggs obtained from sediments of varying ages from Square …

Incorporating Multi-Spectral Imaging Into Long-Term Upland Breeding Bird Monitoring, Kyle William Schumacher

Master's Theses

Quivira National Wildlife Refuge in Kansas, United States partnered with Fort Hays State University Hays, KS in 2014 to begin a collaborative research project that aimed to develop a long-term monitoring protocol guided by the Comprehensive Conservation Plan for the refuge published in 2013. This plan identified specific wildlife taxa underrepresented in management impact assessments throughout the property. As a result of this plan, surveys were established to monitor interactions between upland breeding birds and the vegetation community. I conducted point count surveys in 2016, 2017, and 2018 for 122 observation points across four transects. I measured seventeen vegetation variables …

Photosynthetic Activity Under Low Light, Danijela Lonco

Williams Honors College, Honors Research Projects

Are bacteria capable of undergoing oxygenic photosynthesis under low-light conditions inside of caves? Inside of an Australian cave, Chlorophyll f was recently discovered. This chlorophyll pigment was found to demonstrate the capability for photosynthesis, suggesting that Chlorophyll f extends the spectrum of usable light needed for oxygenic photosynthesis (Lars, 2015). Due to the findings in this study, a team went to Carlsbad Caverns to see if there were any bacteria capable of undergoing oxygenic photosynthesis under low light.

Relationships Between Factors Influencing Biofilm Formation And Pathogen Retention In Complex Rhizosphere Microbial Communities, Aaron Coristine

Theses and Dissertations (Comprehensive)

Riparian wetlands are unique habitats facilitating all forms of life. The riverbanks of these environments provide ideal conditions for bacteria, plants, and higher organisms. Of particular interest to this research was the variation in microbial community structure at high, intermediate and poor water quality impacted areas. Assessing the capabilities of plants to retain microbial pathogens was identified. Root systems and corresponding soil are ideal locations for bacterial deposition, resulting in attachment at these areas. Biofilm production in these regions is important for long-term establishment, leading to persistence and potential naturalization. Opportunistic pathogens originating from mammalian fecal matter are introduced into …

Avian Community Responses To Bison Grazing In North American Intermountain Grasslands, Danielle A. Fagre

Graduate Student Theses, Dissertations, & Professional Papers

Grassland and shrubland songbird species are a guild of conservation concern in North America. Many of these species have experienced severe population declines, due to habitat loss and land use change. This makes the conservation and management of remaining habitat of crucial importance for this guild. Grazing by large herbivores is an ecosystem process in grassland systems, and in North America, one of the major historic grazers was the Plains bison (Bison bison). Bison are considered ecosystem engineers, because they modify habitat to be more or less suitable for other species, such as grassland and shrubland songbirds. Bison …

Near-Surface Permafrost Ground Ice Characteristics And Ecological And Physical Drivers Of Transient Layer Ice Content In Discontinuous Permafrost, Jason Paul

Theses and Dissertations (Comprehensive)

Accelerated climate warming in northern regions is causing permafrost degradation, leading to the reduction of the areal extent of permafrost. Permafrost is the foundation for many northern ecosystems and communities, so its thaw can have important ecological and societal consequences. Thaw of ice-rich permafrost can cause subsidence of the ground surface proportional to excess ice content. Terrain settlement can cause ponding or damage to infrastructure. Following a surface disturbance that removes much of the vegetation cover, a shift in the ground thermal regime can cause an increase in active layer thickness and rapid thaw of the top portion of permafrost. …