Life Sciences Commons^™

Trophic Dynamics Of The Lake Superior Fish Community, Ariel Edwards

All NMU Master's Theses

The Lake Superior food web has undergone many changes in recent decades, including the rehabilitation of the native apex predator lake charr (Salvelinus namaycush) and the introduction of several nonnative species. The trophic linkages and ecological requirements of the entire fish community, including predators and prey fishes, has not been assessed on a whole-lake scale in over a decade. Here, I investigated the trophic dynamics across multiple regions of the lake, and estimated the consumptive effect of lean lake charr in one region of Lake Superior. From April to October of 2021, a total of five predator, four …

Climate Refugia For Neotropical Snakes: Implications Of Microhabitat Use And Diet Specialization, Consuelo Alarcon

Masters Theses

Aim: The aims of this study were to compare the locations of climate refugia and diversity patterns of the Neotropical tribe Pseudoboini and to provide critical analysis of the potential role of climatic stability and ecological specialization in the contemporary and historical distribution of this group of snakes. We expected species with narrow ecological requirements to occupy climatically stable areas, whereas generalists and arboreal species would occupy areas with more variable climate.

Location: South America

Methods: We compiled observations from the scientific literature and herpetological notes (1844-2019) with additional data from museum collections throughout South America to …

An Analysis On How Housing Status Influences The Gut-Brain-Axis For Populations In And Around The Skid Row Area Of Los Angeles, California, Mauricio Guzman

Pitzer Senior Theses

Over recent years, the “microbiota-gut-brain axis” (MGBA) has garnered significant attention in the scientific community. Specifically, perturbations of the MGBA via stress and dietary intake have been linked to a wide-range of diseases including gastrointestinal diseases, metabolic diseases, mood disorders, and cognitive diseases. However, most studies have been solely conducted on mice models and have yet to consider the more complex, intricate systems that impact the human body. In addition, researchers have yet to consider the populations who may be most susceptible to chronic stress and negative dietary outcomes. Drawing from the fields of medical sociology, non-invasive human biology, and …

Survey For Usage Of And Interest In Personalized Nutrition As A Possible Health Approach, Kimberly Garrett

Biological Sciences Undergraduate Honors Theses

Dietary factors can lead to chronic diseases and impact certain health factors such as sleep and mood. Personalized nutrition is based on an individual’s phenotype and genotype to meet specific dietary needs. This approach could be an intervention to benefit an individual’s health. This study surveyed a population to analyze the population’s view on and usage of personalized nutrition. The use of personalized nutrition was minimal, but there was interest within the population. In addition, a relationship between health and mood was found. However, the sample size was a limiting factor for this study. Future directions could include studying why …

Methyltransferase Mystery: Epigenetic Mechanisms Induced By Food Limitation In Daphnia Pule, Trenton C. Agrelius

Theses and Dissertations

Daphnia are ecologically important organisms that have been well studied in the context of evolution, ecology, ecotoxicity, and genomics. Daphnia have strong maternal effects in which the environment experienced by the mother can alter offspring disease resistance, life history traits, and morphology, as well as gene expression and methylation for multiple generations. Coupled with their ability to reduce genetic differences via parthenogenesis, Daphnia are an ideal system for epigenetic studies involving the transmission of maternal effects. Using two clones of Daphnia pulex, we investigated the plasticity of life history and DNA methyltransferase (Dnmt) gene expression with respect to food …

A Review Of Current Methods In Avian Dietary Analysis And Their Integrated Application To Characterize The Trophic Niche Of Louisiana Waterthrush (Parkesia Motacilla)., Brandon Hoenig

Electronic Theses and Dissertations

Characterizing a species’ dietary composition presents an avenue to understand many facets of its ecological niche and can provide essential information for the species’ long-term conservation. To date, the vast majority of diet studies have relied on direct identification of prey during foraging observations or from diet samples to characterize the dietary habits of birds. However, advancements in laboratory-based approaches have revolutionized the field of trophic ecology by allowing researchers to indirectly infer dietary habits with higher resolution across greater time scales. Here, I apply two of these laboratory-based techniques, namely DNA metabarcoding and stable isotope analysis, to characterize the …

The Ecological Role Of Cassiopea In Shallow Mangrove Habitats, David Marcel Durieux

USF Tampa Graduate Theses and Dissertations

Upside-down jellyfish, Cassiopea sp., can be locally abundant in shallow mangrove habitats throughout the tropics and subtropics. Unlike other jellyfish, Cassiopea sp. are epibenthic. Due to this unique lifestyle and their ability to achieve high population densities, an understanding is needed of their ecological impacts both individually and in aggregations, particularly given that Cassiopea sp. ranges are expanding poleward due to global climate change. We quantified the fluid flow produced by Cassiopea sp. feeding currents and found that an average-sized Cassiopea sp. can transport over 200 l/h of water in the vertical excurrent jet of their feeding current. Populations of …

Fecal Findings: Investigating Eastern Massasauga Rattlesnake Diet Using Dna Metabarcoding, Alyssa Swinehart

Masters Theses

Characterizing the diet of imperiled species using minimally invasive methods is crucial to understanding their conservation requirements. DNA metabarcoding methods have been used to characterize the diet primarily in mammalian systems, while reptiles are heavily underrepresented in this literature. Here, we apply a DNA metabarcoding approach to study the diet of the eastern massasauga rattlesnake (Sistrurus catenatus); a Federally Threatened snake found throughout the Great Lakes Region. Eighty-three fecal samples collected across 10 different massasauga populations located in Michigan were sequenced. We use universal metazoan primers and develop a host-specific oligonucleotide blocker to uncover the full potential diet …

Analyses Of Coyote (Canis Latrans) Consumption Of Anthropogenic Material And Dietary Composition In Urban And Non-Urban Habitats, Audrey A. Hayes

Browse all Theses and Dissertations

Coyotes are a generalist species that have adapted to nearly every terrestrial habitat in the United States. The species’ success is heavily attributed to their omnivorous diets and tolerance for environments that are regularly disturbed. Because the larger predator species that typically act as apex predators are sensitive to highly fragmented landscapes, the coyote is the functioning apex predator in many ecosystems where large predators, such as wolves, have been extirpated. The coyotes’ ecological role in urban ecosystems has received much attention in the last few decades as the species’ presence in cities and suburbs has increased, along with human-coyote …

The Relationship Between Population Dynamics And Dietary Preferences Within Two Snake Genera (Storeria And Thamnophis), Molly M. Dixon

Master's Theses and Doctoral Dissertations

Amidst massive losses in biodiversity, it is vital to identify the factors driving species declines. The main objective of this research was to assess dietary differences between Storeria dekayi and Thamnophis sirtalis and their less abundant and more geographically restricted sister species, Storeria occipitomaculata and Thamnophis butleri, in Illinois and Michigan. I hypothesized that greater abundance and more cosmopolitan distribution are associated with consuming a wide variety of prey and more nonnative prey. To assess diets, I conducted field surveys of Storeria and Thamnophis and analyzed DNA metabarcoding data from fecal samples. I found no significant difference in the …

Holistic Approaches For Invasive Species Management: Exploring Biotic Resistance Of European Green Crab (Carcinus Maenas) Via River Otter (Lontra Canadensis) Diet, Bobbie Buzzell

WWU Graduate School Collection

Establishment of the European green crab (Carcinus maenas) on the west coast United States has led to concerns regarding loss of eelgrass beds and influence on marine communities. To begin examining whether predators can potentially buffer green crab expansion, I studied river otter (Lontra canadensis) diet from scat remains and estimated green crab abundance from removal trapping efforts. River otter scats on the Wa’atch and Tsoo-Yess rivers, Washington, USA, were collected during August-September 2018 and April-September 2019. Hard remains of prey were reported as percent frequency of occurrence, and green crab prey were compared to monthly …

Competitive Interactions: Spatial And Temporal Niche Partitioning Between Brook And Brown Trout In Southwest Michigan, Frederick J. Glassen

Masters Theses

Niche diet partitioning between Brook Trout and Brown Trout were studied in two southwestern Michigan, USA streams, one dominated by Brook Trout, the other with both Brook and Brown Trout. Brook Trout are endemic to eastern North America and have been introduced throughout the world for sport fishing. Brown Trout were first introduced to Michigan in 1883 using a genetic strain from Germany. Stomach contents were collected from a population of Brook Trout in the absence of Brown Trout in Frost Creek, while the other population was in potential competition with Brown Trout in Cedar Creek. Absent Brown Trout, Brook …

Novel Method To Determine Paleodiet Of Extinct Equid Merychippus Sp. Using Dental Calculus, Ranjit Z. S. Virk

Senior Honors Projects, 2020-current

Within the Miocene Epoch, the emergence of grasslands within North America coincided with the incidence of higher-crowned teeth (hypsodonty) within the proto-horse Merychippus that allowed for the inclusion of these expanding grasslands as a food source. As herbivorous paleofauna consume plant matter, microscopic remains become incorporated within dental calculus and, due to their diagnostic morphology, can be used to identify dietary components. In Merychippus, the recovery of plant microfossils holds the potential to provide greater clarity on the paleodiet of these equids. In the present study, the purpose was to quantify and compare Merychippus paleodiet constituents among sample groups. …

A Comparison Of Coyote Diets In Urban And Rural Habitats In The Piedmont Of South Carolina, Bethany Krug

Graduate Theses

With increasing rates of urban expansion, interactions between humans and wildlife become inevitable. These urban environments present novel situations to native species, frequently resulting in their displacement or extirpation. However, some species, often referred to as “urban adapters”, have thrived in these landscapes. Coyotes (Canis latrans) are a prime example of a species that has adapted to exploit urban habitats. Coyotes are omnivores with food choices ranging from small/medium mammals to invertebrates depending on habitat. With their recent range expansion into the Southeast, little is known of their behavioral ecology in the region, especially details relating to their diet. Macroscopic …

Diet Analysis Of Stranded Bottlenose Dolphins (Tursiops Truncatus) In Virginia, Kristen Marie Volker

Biological Sciences Theses & Dissertations

This study describes the diet of bottlenose dolphins (Tursiops truncatus) stranded in Virginia via stomach content analysis and considers factors such as proportion of numerical abundance and reconstructed mass, frequency of occurrence, average reconstructed prey size, prey diversity and quantity, and otolith degradation code. Fish size was estimated via regression equations established from local fish collected during the study that derive wet weight directly from otolith length or width. Squid size is estimated from previously published equations. Soniferous fishes dominated the diet, especially Atlantic croaker, spot, and seatrout spp., adding evidence to the theory that bottlenose dolphins passively …

Diet Of A Recently Reintroduced River Otter (Lontra Canadensis) Population In Taos County, New Mexico, Gabriela Alexandra Wolf-Gonzalez

Theses and Dissertations--Forestry and Natural Resources

North American river otters (Lontra canadensis), native to every U.S. state and Canada, experienced extensive population decreases and range reduction until the mid-20th century as a result of overexploitation and habitat loss during European colonization. The last known river otter in New Mexico was killed on the Gila River in 1953, although unverified reports continued thru 2008. After a nearly 60-year absence from New Mexico, 33 adult river otters were reintroduced to the Rio Pueblo de Taos in the northern part of the state between 2008-2010; however, they were not subsequently monitored or studied. I characterized diet of …

Coaggregation Patterns And Surface Characteristics Of Lactobacillus Rhamnosus Gg Under Varying Nutrient Conditions, Amanda Rielinger

Senior Honors Theses and Projects

Lactobacillus rhamnosus GG (LGG) is one of the best studied probiotic organisms. The ability of probiotics to adhere to other microorganisms and the intestinal epithelium is thought to play a major role in their protective functions. Coaggregation is an important mechanism for biofilm formation by microorganisms. The goals of this study were to examine the ways in which nutrient variation affects intercellular interactions between LGG and other gut microbes and the hydrophobic character of LGG. We hypothesized that nutritional variation may affect the ability of LGG to coaggregate and form biofilms and thus affect its probiotic characteristics and ability to …

Seasonal Diet Variation In Thirteen-Lined Ground Squirrel (Ictidomys Tridecemlineatus) In Southernwestern Michigan, Austin Menzmer

Master's Theses

Thirteen-lined ground squirrels (Ictidomys tridecemlineatus) are omnivorous ground squirrels that range from Texas to Alberta and from Michigan to Utah. The amount and type of both animal and plant matter in their diet may vary both geographically and seasonally. The present study was motivated by prior work, based on δ13C analysis of incisor enamel of thirteen-lined ground squirrels from a colony in southwestern Michigan, suggesting that these animals underwent a pronounced, late-season shift in diet from predominantly C3 to C4 plants. However, this inferred dietary shift was not directly demonstrated. Here, I tracked diet of thirteen-lined ground squirrels in southwestern …

Diet Composition Explains Reductions In Stream Salamander Occupancy And Abundance Along A Conductivity Gradient, Jacob Matthew Hutton

Theses and Dissertations--Forestry and Natural Resources

Changes in land use such as mountaintop removal mining with valley fills (MTR/VF) affect chemical, physical, and hydrological properties of headwater streams. Although numerous stream taxa have experienced significant declines from MTR/VF, stream salamanders appear to be particularly sensitive. Yet, the specific mechanism(s) responsible for the population declines has eluded researchers. We sampled salamander assemblages across a continuous specific conductivity (SC) gradient in southeastern Kentucky and estimated occupancy rates and abundance estimates along this gradient. We also examined the diet of larval and adult salamanders to determine if autochthony (A/T prey), total prey volume, and body condition is influenced by …

Total Antioxidant Levels Of Individual Foods Versus Combinations Of Food And The Effect On Apoptotic Induction In Hela Cells, Natalie Van Ochten

Undergraduate Honors Thesis Collection

Cancer affects over 14.5 million U.S. citizens of all ages, socioeconomic statuses, and races. Some countries have much lower cancer incident rates than the U.S. One major contributing factor to the lower incident rates is diet. Diets in countries with low rates of cancer include antioxidant-rich foods like raw fruits, raw vegetables, and spices. Studies have shown that antioxidants in black tea and berries induce apoptosis in cancerous cells. Because studies have shown that diet and cancer rates are related, it is important to analyze what we eat and how it impacts us. In this study, I quantified antioxidant levels …

Bacterial Community Ecology Of The Colon In Mus Musculus, Rachel Marie Nettles

Theses and Dissertations

The gut microbiome is a community of closely interacting microbes living in the gastrointestinal tract. Its structure has direct relevance to health. Disturbances to the microbiome, such as due to antibiotic use, have been implicated in various diseases. The goal of this study was to determine how the gut microbiome reacts to and recovers from disturbance caused by antibiotics. Because diet also influences the microbiome, this study included the interaction between diet and antibiotics. Half of the mice in each diet treatment were given antibiotics to disturb their microbiomes. After cessation of antibiotics, mice were paired in combinations within diets …

Age And Sex-Specific Effect Of Caloric Restriction On Circadian Clock And Longevity-Associated Gene Expression, Arten Andreyevich Astafev

ETD Archive

The rhythms in the expression of circadian clock genes are affected by calorie restriction (CR), a dietary paradigm known to increase lifespan. In our current study, we show that circadian rhythms are influenced by sex and the effects of CR are different between males and females. In particular, we found a group of clock genes which showed a sex-dependent difference in expression, as well as in response to CR (Rev-Erb α, Ror γ and both Cryptochromes: Cry1 and Cry2 genes). Two clock genes showed no difference in expression but their response to CR showed sexual dimorphism (Ror α and Rev-Erb …

The Effect Of Seasonal Fish Migration On Energy Budgets In Two Coastal Michigan Streams, Emily M. Dean

Masters Theses

Migratory fish are known to seasonally enter coastal stream systems but the magnitude of the effects these migrations have on stream energy budgets is not fully understood. The Laurentian Great Lakes have several introduced and native adfluvial fish, where only a few studies have investigated the impacts of their migration on energy budgets in Michigan coastal streams. We quantified the contribution of energy from Chinook salmon (Oncorhynchus tshawytscha) muscle and eggs, steelhead (Oncorhynchus mykiss) eggs, and larval white suckers (Catostomus commersonii) to coastal stream energy budgets. Energy densities and energy delivered to streams were estimated using bomb calorimetry and annual …

Natural History And Conservation Of Bolitoglossine Salamanders In Central Panama, Leslie Caren Brinkman

MSU Graduate Theses

I conducted a mark-recapture study to assess the natural history of a Neotropical salamander community in three discrete 4–6 week sampling periods at Chorro Las Yayas, a protected natural area of about 8000 m2 in central Panama, during an extended drought. I captured 87 Bolitoglossa biseriata, 17 Oedipina complex, and 15 O. parvipes. Bolitoglossa biseriata, had a mean mass of 0.8 ± 0.4 g with a mean snout-vent length (SVL) of 31.45 ± 5.30 mm. Bolitoglossa biseriata was active throughout the night, and its detection rate varied with season, air temperature, and amount of precipitation in the previous 24 h. …

Ecology Of Coyotes (Canis Latrans) In The Greater Detroit Area Of Southeastern Michigan, William B. Dodge

Wayne State University Dissertations

Coyote distribution and habitat use, diet and foraging behavior and space use patterns were investigated in the greater Detroit area of southeastern Michigan. We found evidence of coyotes on 24 of 30 (80%) suburban and 7 of 11 (64%) urban plots. Overall fifty-eight percent of coyote evidence was found within edge habitats, with den sites and tracks the only types of evidence found strictly in interior habitats. Land cover around evidence points included more wooded land cover than expected in suburban areas, suggesting the importance of tree cover for coyote occupancy, and more open space and wooded land cover than …

Trophic Interactions And The Efficacy Of Milfoil Weevils For Biocontrol Of Eurasian Watermilfoil In Wisconsin Lakes, Kristopher Andrew Maxson

MSU Graduate Theses

Eurasian water-milfoil (Myriophyllum spicatum L., henceforth “EWM”) is the most heavily managed nuisance submersed aquatic plant in the United States. EWM’s rapid spring growth and formation of dense surface mats inhibits native macrophyte communities, serves as poor-quality habitat for fish and macroinvertebrates, impacts recreation, and can clog water supply infrastructure. The milfoil weevil (Euhrychiopsis lecontei Dietz) has been associated with EWM declines in several states, though natural weevil densities are generally too small to effect control. Augmentative biocontrol has had varied success and fish predation may account for high weevil mortality. Weevils were augmented in 4 northern Wisconsin lakes in …

Prothonotary Warbler Nestling Diet And Growth In Response To Variation In Aquatic And Terrestrial Food Availability, Jenna C. Dodson

Theses and Dissertations

Food supply has been suggested as the main determinant of reproductive success in birds. Riparian species can take advantage of seasonal pulses of both terrestrial and aquatic prey, though aquatic resources are often overlooked in studies of diet and reproductive ecology. This study investigates the flux of both aquatic (mayfly) and terrestrial (caterpillar) prey resources and nestling diet of the Prothonotary Warbler throughout the breeding season in two eastern Virginia sites. One site had significantly higher aquatic prey (mayfly) availability. Nestling diet was generally reflective of prey availability, and nestlings grew faster at the site with high aquatic prey availability. …

Reintroduction Biology Of Head-Started Ornate Box Turtles, Eric R. Sievers

MSU Graduate Theses

The ornate box turtle (Terrapene ornata) is a prairie-dwelling species that has experienced population declines, especially near the northern edge of its range. In order to provide supporting research for a reintroduction program at the Upper Mississippi River National Wildlife and Fish Refuge in northwestern Illinois, I compared the relative success of different approaches to reintroduction. Specifically, I tested the null hypothesis that reintroduced turtles exhibited equal reintroduction success when, 1) released at a site that is known to support a viable ornate box turtle population, 2) ‘soft-released' in a fenced enclosure at a site where very few ornate box …

Human Feeding Biomechanics : Intraspecific Variation And Evolution, Justin Ledogar

Legacy Theses & Dissertations (2009 - 2024)

This study examines feeding biomechanics in modern human crania and those of extinct early members of the human lineage in order to better understand the selective pressures that influenced human craniofacial evolution. Specifically, this study uses finite element analysis to examine: 1) human feeding performance, in terms bite force production and craniofacial strength; 2) intraspecific variation in human feeding biomechanics; 3) feeding biomechanics in fossil hominins, including Australopithecus sediba and Homo habilis, species that are potentially at the root of modern human lineage, and 4) the functional role of purported facial buttresses.

Characterizing The Fitness Landscapes Of Gut Symbionts In Defined Community And Diet Contexts, Meng Wu

Arts & Sciences Electronic Theses and Dissertations

A species' niche is the description of all the environmental conditions required to permit a population of that species to persist, including the effects of the population on those conditions. This definition includes the species' resource requirements, as well as stress tolerances and interactions with other species acting as competitors, predators, parasites, and mutualists. The human gut microbiota serves as a microbial `metabolic organ' tasked in part with the biotransformation of many components of our diet. Relatively little is known about the factors that allow members of the human gut microbiota to persist in a habitat that experiences marked changes …