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Effects Of Water Table Depth And Edaphic Characteristics On Plant Diversity In A Southern Mississippi Pitcher Plant Bog, Patrick Kirby

Master's Theses

This study examined the effects that water table depth and soil characteristics have on plant species richness and species composition within pitcher plant bogs across seasons. Eight piezometers were installed at random distances to monitor long-term water table depth and pressure fluctuations along a ~710-meter line transect traversing upland and bog habitats. Vegetation sampling quadrats (n=128) were set up near each piezometer. Cover data and water table depths were collected in spring and late summer. Soil samples collected from each treatment group were used to obtain soil texture and nutrient data. The summer collection period yielded a total gdiversity of …

The Effect Of Historic Shipwrecks On Sediment Microbiomes In The Northern Gulf Of Mexico, Melissa Brock

Master's Theses

Microorganisms are ubiquitously distributed across all aquatic habitats, but it is the environmental conditions of a habitat that determine which microorganisms can thrive in terms of abundance or metabolic activity. Habitats that experience consistent physical and chemical environmental conditions repeatedly favor specific taxonomic groups which may result in a microbial assemblage that is commonly associated with that habitat (i.e., a core microbiome). Core microbiomes have been identified for a variety of natural marine habitats including methane seeps, wood falls, octocoral, and deep-sea sediments. However, it was unknown if the presence of man-made structures on the seafloor, including historic shipwrecks, also …

Dynamics And Ecological Implications Of The Ulva-Zostera Ecotone In Elkhorn Slough, California, María Vila Duplá

Master's Theses

Ecotones are transitional areas between adjacent ecological communities that have unique ecological qualities defined by space and time scales, and by the interactions between adjacent systems. Ecotones play an essential role in supporting biologically diverse communities, and are sensitive indicators of global change. An Ulva-Zostera ecotone extends along the northern shore of Seal Bend in Elkhorn Slough, an estuary located in central California. Although previous studies have mentioned the presence of the Ulva-Zostera ecotone, this was the first study to focus on understanding its driving factors, spatiotemporal dynamics, and overall ecological implications. A combination of habitat monitoring, water quality assessments, …

Comparative Thermal Ecology Of Coastal And Inland Pacific Rattlesnakes (Crotalus Oreganus), Hayley Layne Crowell

Master's Theses

Global biodiversity is declining as a direct result of anthropogenic climate change. Ectothermic species have become focal organisms for studying the ecological effects of altered climates due to the clear relationship between environmental temperatures and ectotherms’ basic physiological functions. Historically, examinations of these effects have focused heavily on heliothermic lizards, and most others have tended to focus on single populations or sympatric species within a single community. Addressing the longterm energetic implications of environmental temperature variation will provide valuable insight into the cascading physiological effects that certain populations or species may experience as a result of altered climates.

In this …

The Impact Of Junk Food Marketing Regulations On Food Sales: An Ecological Study, Yumi Kovic

Master's Theses

Objectives. To evaluate the impact of junk food marketing policies implemented worldwide from 2003 through 2014 on nationwide junk food sales and to identify the most effective policy characteristics in reducing junk food sales.

Methods. Junk food marketing policy data were obtained and categorized through a thorough literature review. These data were analyzed using a repeated measures design against EuroMonitor junk food sales data from 2002 and 2016.

Results. Countries with junk food marketing policies saw a decrease in junk food sales after implementation, while those without said policies saw an increase in sales. Countries with statutory policies saw a …

Characterizing Ecological And Genetic Patterns Of The Colonizing Species Dubautia Scabra On The Big Island, Hawaii, Samantha Kaleigh Naibauer

Master's Theses

The Hawaiian Silversword Alliance (HSA) is a group of approximately 35 endemic species found on the Hawaiian Islands. The HSA is of particular interest due to the vast adaptive responses of its members across the Hawaiian Islands. Each of these plant species is generally limited to a very specific habitat type with a unique morphology and physiology. Dubautia scabra is the first angiosperm colonist of new lava flows, arriving in as few as two years after lava cools. The critical role D. scabra plays in this ecosystem gives a unique starting point for understanding downstream ecological processes such as seed …

Cold Acclimation Response Of Non-Native Italian Wall Lizard (Podarcis Siculus) Populations From New York And California, Daniel Haro

Master's Theses

Understanding how organisms respond to climatic variability and novel conditions is becoming an increasingly important task for ecologists. For ectotherms in the northern hemisphere, the response to cold is of special interest, considering that poleward range expansion events and increasing variability of temperatures during winter are already being observed as consequences of a warming planet. Though direction of change in physiological variables in response to cold is well studied in ectotherms, the extent to which traits can change and the rate at which they can change is not.

We compared the extent and rate of change in cold tolerance (CT …

Diets And Stable Isotope Signatures Of Yellowtail Rockfish (Sebastes Flavidus) In Central California, Jennifer Chiu

Master's Theses

Studies of fish diets can improve the understanding of trophic distributions and the predatory role of a species in an ecosystem. Identifying the spatial and temporal variability in the diets of fishes can provide useful information for stock assessments and management. Yellowtail Rockfish (Sebastes flavidus) are a commercially and recreationally important fishery species, and abundant along the central California coast, yet the most recent studies of diets occurred over 20 years ago in Oregon and Washington. To provide current information from California, I examined the food habits of Yellowtail Rockfish collected near Cordell Bank, the Farallon Islands, and Half Moon …

Opioid Use And Opioid Use Disorder Services In Connecticut, Julie Christensen

Master's Theses

No abstract provided.

Effects Of Wave Action On The Structure Of Fish Assemblages Across An Exposure Gradient, Lauren Liddon

Master's Theses

Disturbance affects the function and diversity of ecosystems. Increased wave exposure to salt marsh can disturb sediments and cause a loss of habitat. The purpose of this study was to explore the effects of increased wave exposure on diversity, abundance, and functional ecology of estuarine fishes. If increased wave exposure is acting as a disturbance to these habitats, ecological theory (Intermediate Disturbance Hypothesis) predicts that diversity will peak at intermediate frequencies and intensities of disturbance. Fish were sampled from 10 sites monthly for 6 years. The sites were assigned to different exposure categories (Open, Intermediate, and Sheltered) using an exposure …

Variation In Organismic Rna And Dna Content: Analysis And Application To The Assessment Of Living Planktonic Biomass, Elizabeth Lam Gagneron

Master's Theses

Modern analysis of DNA and RNA nucleic acid sequences has yielded profound changes in our understanding of the genetic biodiversity of planktonic organisms within the microbial food web of aquatic ecosystems. However, the bulk environmental concentrations of DNA and RNA, and their relative ratios, also potentially provide important information on the biomass and metabolic activity of planktonic organisms. Currently, there is a need to quantify the relative living biomass levels of natural water contained in ships’ ballast tanks to regulate the spread of aquatic invasive species (AIS) resulting from ballast water discharge practices within the international shipping industry. Ultraviolet (UV) …

Phylogenetics, Biogeography, And Climate Niche Variation Of South Pacific And Hawaiian Psychotria, Elaine Zhang

Master's Theses

Why do some species have broad geographic distributions, while other species are confined to a narrow distribution? Species age, ecological niche, or dispersal traits may help explain why some insular species are abundant and found on many islands, while others are rare and restricted to one island. In this study, I inferred a robust, time-calibrated phylogeny of the Hawaiian Psychotria, using two nuclear and eight chloroplast loci, sampling 67 individuals. I coupled my phylogenetic hypothesis with climatic data, ecological niche modeling, and morphological dispersal characteristics to explain the variation in number of islands occupied by each species. My inferred phylogeny …

Circadian And Circatidal Rhythms Of Protein Abundance In The Intertidal Mussel Mytilus Californianus, Cory Elowe

Master's Theses

The intertidal zone is a dynamic environment that fluctuates with the 12.4-h tidal and 24-h light/dark cycle to predictably alter food availability, temperature, air exposure, wave action, oxygen partial pressure, and osmotic conditions. Intertidal sessile bivalves exhibit behavioral or physiological changes to minimize the persistent challenges of fluctuating environmental conditions, such as adjusting gaping behavior and heart rate. At the cellular level, transcriptomic studies on mussels’ baseline circadian and circatidal rhythms have determined that the circadian rhythm is the dominant transcriptional rhythm. However, as proteins reflect the basic molecular phenotype of an organism and their abundance may differ greatly from …

Effect Of Fragmentation And Habitat Type On Coastal Nekton In Mississippi, Thomas Bennett Sevick

Master's Theses

Coastal wetlands are extremely productive ecosystems that support an abundance of organisms at higher tropic levels. Coastal wetlands also act as important buffers from storms and help protect major cornerstones of coastal economies, such as tourism and fisheries. Despite the clear need for the protection of these habitats, anthropogenic use of coastal wetlands has increased in frequency and intensity, resulting in the fragmentation of once continuous habitats. A central challenge to assessing the impact of marsh fragmentation is the lack of quantitative distribution and abundance data from specific habitat types. This is especially true for species that are not commercially …

Long-Term Feeding Ecology Of Early-Stage Striped Bass (Morone Saxatilis) And American Shad (Alosa Sapidissima) In The Hudson River Estuary, Michael G. Smircich

Master's Theses

No abstract provided.

Recreation Ecology Of Colorado Fourteeners: An Assessment Of Trail Usage And Impacts, James C. Ewing

Master's Theses

The popularity of climbing Colorado’s 14,000 ft. peaks, or “Fourteeners”, has risen dramatically in recent years, raising important sustainability and management questions. Moreover, groups managing the peaks operate with major capital constraints so their efforts need to be informed, prioritized, and efficient. This paper gauges the dynamics of trail usage, explanatory variables, and recreational impacts across all 58 Fourteeners, and details evaluation adjustments that minimize error and produce results in-step with the resource management framework. Relative to a baseline study completed in 2005, substantial changes occurred in trail usage and impact dynamics. The greatest changes were concentrated on peaks previously …

Complex Effects Of Nitrogen Pollution And Grazing On Nectar Resources Of The Adult Bay Checkerspot Butterfly (Euphydryas Editha Bayensis), Nidhi Jain

Master's Theses

Recent anthropogenic increases in atmospheric nitrogen due to urbanization and combustion have had many adverse effects on natural systems, including loss of biodiversity, especially in sensitive habitats. One such region is the serpentine ecosystem of Coyote Ridge in San Jose, CA, the last refuge for recurring populations of the federally threatened Bay Checkerspot Butterfly (BCB) (Euphydryas editha bayensis). Increases in non-native grass cover and decreases in native forb cover (including cover of the BCB’s native larval host plants) have been attributed to the fertilizing effects of increased atmospheric nitrogen deposition. To counteract this effect, grazing has been implemented as a …

Effects Of Small-Scale Substrate Complexity And Heterogeneity On Rocky Intertidal Species Interactions, Sara E. Worden

Master's Theses

The barnacle assemblage in the high rocky intertidal zone has provided an excellent study system to examine species interaction webs. This assemblage consists of a small set of species: barnacles, a variety of macroalgae, and a suite of limpet grazers. Despite the extensive intertidal research occurring along the central California coast, little is known about this specific interaction web and what physical factors may influence it in this region. This study examines the direct, indirect, positive, and negative interactions between the intertidal barnacle Balanus glandula Darwin, the brown seaweed Pelvetiopsis limitata Gardner, and limpet grazers, and how the underlying rock …

Assessing Knowledge And Attitudes Of The Human Papillomavirus Infection And Vaccine Among Adolescents In Hartford, Ct, Anita C. Chandrasekaran

Master's Theses

No abstract provided.

Benthic Macroinvertebrates In Uvas Creek, California, Downstream Of A Reservoir, Carole Ann Foster

Master's Theses

I sampled macroinvertebrates in May, July, and October 2008 in Uvas Creek, a reservoir-regulated stream in south Santa Clara County, California, to assess what factors (including canopy closure, turbidity, and stream flow) downstream of the reservoir were related to food availability for rearing juvenile Steelhead (Oncorhynchus mykiss). I found benthic and drifting macroinvertebrate biomass was considerably greater during most months in the more open-canopied two sites in the downstream reach as compared to the densely shaded, more turbid and silty two sites in the upstream reach. Abundance of important drifting aquatic invertebrates in May (chironomids, simuliids, and baetids) was proportional …

Conservation Of Bridle Shiner (Notropis Bifrenatus) In Connecticut: Issues In Detecting An Elusive Species, Kasey C. Pregler

Master's Theses

Bridle Shiner (Notropis bifrenatus) is apparently declining over most of its range and is currently listed as a species of concern in Connecticut. Using an occupancy modeling framework in program PRESENCE, my study compared seining and electrofishing backpack unit detection probabilities of Bridle Shiner. This research indicated the apparent decline of Bridle Shiner in the state was in part due to changes in sampling gear used for statewide surveys. Seining used 50 years ago was demonstrably more effective at capturing Bridle Shiner than the currently favored and more frequently used electrofishing gear. In light of this recent finding, …

Photosynthetic Thermal Tolerance And Recovery To Short Duration Temperature Stress In Desert And Montane Plants: A Comparative Study, David William Gallagher

Master's Theses

• Climate change models predict an increase in frequency and amplitude of extreme weather events, including heat waves. To better predict how the composition and distribution of plant assemblages might respond to these changes in temperature, it is important to understand how species currently respond to these extremes. Photosynthetic thermal tolerance (T₂₅)and photosynthetic recovery (RT₂₅) were quantified in 27 species. We also studied the relationships between T₂₅, RT₂₅ and leaf mass per area (LMA). Leaf temperature was also monitored in the field.
• Leaves used in this study were collected from two distinct …

Assessing Landscape Change In Highland Peru With An Emphasis On Tree Cover Change, 1948-2012, Timothy Guy Sutherlin

Master's Theses

Tree cover change was examined around three cities in the central Andes of Peru, 1948-2012, using repeat photography, remote sensing, and ethnographic methods. Forest transition theory provided a framework to study the causes of the changes observed. The repeat photography results show that there were more trees on the landscape in 2012 than there were in 1948. There were increases in smaller groupings of trees visible in the photography that were associated with smallholder intensification in the form of new woodlots, field borders and dooryard trees. The remote sensing results show there was a significant increase in larger patches of …

Plant Invasion Along An Urban-To-Rural Gradient, Carolyn O. Ariori

Master's Theses

Humans are the most important drivers of invasive species introduction and natural habitat transformation globally. Ecological differences between areas of dense human habitation and minimally managed natural habitats were explored across an urban-to-rural gradient of land use in southern New England. These differences were examined through presence/absence and leaf functional traits for a set of invasive species; and urban and rural environmental conditions. Some species were more restricted to particular sites than others along the urbanization gradient, based on introduction history and habitat preference. A priori urban-classified species showed trait values associated with drought tolerance, including higher LWR, greater leaf …

Primary Productivity Distributions Along The River-Dominated Shoreline Of The Bay Of St. Louis, Ms Estuary, Adam Douglas Boyette

Master's Theses

Potential primary production was measured for six consecutive months (July 2010 to December 201 0) at selected stations along the shoreline of the Bay of Saint Louis (BSL) estuary. Monthly surface and a series of subsurface (0.5 m) samples were taken to observe the temporal (monthly and short-term) and spatial variability in production relative to environmental variables that potentially could influence phytoplankton photosynthesis. Daily areal primary production, PP was modeled using photosynthesis-irradiance (P-E) parameters in conjunction with in situ irradiance measurements and biomass data collected during sampling. Although spatial variability was not observed, PP varied seasonally and ranged from 1.90 …

Optimizing Propagation Of Ceanothus Americanus L., (New Jersey Tea), Corylus Cornuta Marsh. (Beaked Filbert), Lonicera Canadensis Bartr. (American Fly Honeysuckle), And Viburnum Acerifolium L. (Mapleleaf Viburnum) By Softwood Stem Cuttings, Julia A. Cartabiano

Master's Theses

No abstract provided.

Spatiotemporal Patterns In Diet And Habitat Use Of Black-Legged Kittiwakes (Rissa Tridactyla) And Thick-Billed Murres (Uria Lomvia) In The Bering Sea, Nathan M. Jones

Master's Theses

This study quantified the multi-trophic influence and spatial structure of a cross-shelf δ15N gradient in the Bering Sea and used it to contrast foraging patterns and seasonal changes in niche width between thick-billed murres and black-legged kittiwakes during July and August, 2008 and 2009. Gut contents of collected seabirds were characterized and stable isotope analyses (δ13C, δ15N) were conducted on whole prey tissues and seabird cheek feathers, pectoral muscle, and liver tissues. Gut contents of both seabird species were spatially auto correlated and varied with habitat type. Feather and muscle tissues indicated that murres underwent a trophic niche contraction with …

Use Of Dna Sequences To Identify Forensically Important Fly Species In The Coastal Region Of Central California (Santa Clara County), Angela T. Nakano

Master's Theses

Forensic entomology has gained prominence in recent years, as improvements in DNA technology and molecular methods have allowed insect and other arthropod evidence to become increasingly useful in criminal and civil investigations. However, comprehensive faunal inventories are still needed, including cataloguing local DNA sequences for forensically significant Diptera. This multi-year fly-trapping study was built upon and expanded a previous survey of these flies in Santa Clara County, including the addition of genetic barcoding data from collected species of flies.

Flies from the families Calliphoridae, Sarcophagidae, and Muscidae were trapped in meat-baited traps set in a variety of locations throughout the …

Activity Patterns And Spatial Resource Selection Of The Eastern Garter Snake (Thamnophis Sirtalis Sirtalis), Matthew Gregory Most

Master's Theses

Snake species usually exhibit seasonal variations in activity patterns, home-range size and the use of respective habitat. Using mark-recapture protocols I marked 96 individual Thamnophis sirtalis sirtalis specimens in Lake Forest, IL to determine the independent variables that best explained habitat selection in a population of Eastern Garter Snakes (T. s. sirtalis). Specifically, I focused on the relationship between seasonal movement and home range size of male and female garter snakes. I analyzed the habitat preferences and spatial ecology of Eastern Garter Snakes during the 2011 sampling season and modeled the relationship between preferred or avoided habitat, in conjunction with …

Assessing The Effects Of Titanium Dioxide Nanoparticles On Microbial Communities In Stream Sediment Using Artificial Streams And High Throughput Screening, Alexandra Ozaki

Master's Theses

Nano-titanium dioxide (nano-TiO2) is an engineered nanomaterial used in a wide array of commercial products. The production and use of large amounts of nano-TiO2 is resulting in the unintended release to the environment. Nano-TiO2 is known to be cytotoxic due primarily to its ability to generate reactive oxygen species, and negative impacts on a variety of organisms have been demonstrated, but the effects of nano-TiO2 on complex microbial communities under ecologically relevant conditions have rarely been tested. We conducted a controlled manipulative experiment using recirculating model streams dosed with a one-time amendment of 1mg L-1 nano-TiO2 (specifically P25). Within one …