Life Sciences Commons^™

Improving Understanding Of Forest Communities And Biodiversity With Multi-Dimensional Landscape Gradients, Ben J. Padilla

Doctoral Dissertations

This dissertation was motivated by a desire to understand the effects of habitat degradation and urbanization on a single species in a single study system in western Massachusetts, the red-backed salamander (Plethodon cinereus), but along the way unexpected conceptual and methodological hurdles caused the work to grow into a multi-species, multi-region, and multi-scale endeavor. As I designed my dissertation research and began considering approaches to quantifying heterogeneity and human influence in my study landscape, I recognized inconsistencies in methods used to define and quantify landscape metrics, particularly in urban systems. To investigate further, I conducted a critical review …

Exposing Lettuce Plants To Cyanobacteria In A Closed Hydroponics System To Reduce Cyanobacterial Growth And Production, Emily Eberly

Honors Projects

Sandusky Bay is largely populated by cyanobacterial algal blooms, mainly formed by Planktothrix. Fertilizers containing nitrogen and phosphorus run from agricultural lands into the bay, building up excess nutrients forming eutrophic waters. The Planktothrix feed off these nutrients and grow into algal blooms. To determine a potential solution to the growth of these blooms, I implemented a hydroponics system involving Lactuca Sativa for analysis of Planktothrix growth and productivity. Four different nutrient conditions were added to a Planktothrix-only solution and a solution growing Planktothrix with the lettuce in the hydroponics system. The four conditions consisted of no nutrient …

Prevalence Of Rats And Rodent Borne Pathogens Across Post-Katrina New Orleans, Bruno Marco Ghersi

Doctoral Dissertations

Disasters are happening at an increasingly higher rate and intensity a trend that is expected to continue as more humans migrate to coastal urban areas. Disasters, and as importantly, disaster recovery can affect how native and pest populations will recover. My aim was to improve understanding of disease risk by evaluating the socioecological conditions that have shaped commensal rat recovery and distribution, as well as the pathogens they carry, across New Orleans after Hurricane Katrina. I first estimated relative abundance and distribution of commensal rats from rodent trapping conducted between mid-2014 and early-2017 across 96 sites in 10 areas of …

Root Stage Distributions And Their Importance In Plant-Soil Feedback Models, Tyler Poppenwimer

Doctoral Dissertations

Roots are fundamental to PSFs, being a key mediator of these feedbacks by interacting with and affecting the soil environment and soil microbial communities. However, most PSF models aggregate roots into a homogeneous component or only implicitly simulate roots via functions. Roots are not homogeneous and root traits (nutrient and water uptake, turnover rate, respiration rate, mycorrhizal colonization, etc.) vary with age, branch order, and diameter. Trait differences among a plant’s roots lead to variation in root function and roots can be disaggregated according to their function. The impact on plant growth and resource cycling of changes in the distribution …

Population Structure Of A Federally Endangered Plant (Astragalus Jaegerianus Munz, Fabaceae) With Limited Range Using Microsatellites, Sueann Neal

Electronic Theses, Projects, and Dissertations

Studies on population genetics examine the relationship and effects of population structure, migration, gene flow and demographic history, and are therefore important in the conservation of endangered species. Astragalus jaegerianus, a critically federally endangered species found in a geographically restricted range is investigated to determine population structure and genetic variation. Previous research on A. jaegerianus focused on DNA sequence data for cpDNA and nrDNA showed no variation. Further research on A. jaegerianus utilizing AFLP’s on the whole genome indicated substantial gene diversity and population structure consistent with geographically widespread species. AFLP research is a cost-effective process to identify levels …

Assessment Of Genetic Diversity In Largetooth Sawfish, Pristis Pristis, Populations Over The 20th Century, Ann Fearing

Master's Theses

The Critically Endangered Largetooth Sawfish, Pristis pristis, experienced global declines in range and abundance over the past century and Australia is now their last stronghold. This research aimed to understand whether these declines have been accompanied by a reduction in levels of genetic diversity. Using P. pristis tissue samples sourced from natural history specimens, three fragments (616-bp, 386-bp, 141-bp) in the mitochondrial DNA (mtDNA) control region were PCR-amplified. At each fragment, significant genetic structure was found in P. pristis overall (Φ_ST=0.946, N=9; 0.813, N=54; 0.771, N=99). The Indo-West Pacific and Atlantic/Eastern Pacific each harbor genetically distinct lineages of …

Fish And Macroinvertebrate Response To Restoration And Conservation Efforts, Madison C. Cogar

MSU Graduate Theses

Fish and macroinvertebrate response to restoration and conservation efforts varies in regards to the size and structure of the system (e.g. headwater streams in WV versus large rivers such as the Mississippi River). This project reviews fish and macroinvertebrate rebound in treated acid mine drainage (AMD) streams in WV as well as macroinvertebrate drift patterns in the Mississippi and Missouri Rivers. AMD is a product of a chemical reaction resulting in an acidic water outflow from mining sites, which may harm aquatic life. As a response, passive AMD treatment systems have been installed. I tested the effectiveness of remediation by …

Defining Bee Pollinator Community Composition In Tennessee Soybean, Andrew L. Lawson

Masters Theses

Two planting dates of various soybean varieties were planted in Jackson and Knoxville, TN during 2018 and 2019 with the overall intent of surveying the diversity bee (Hymenoptera) genera in these agroecosystems and also to assess the potential for using late maturing soybean as a food resource for bees during the dearth of floral resources that often occurs during the fall. We also investigated how manipulating planting dates and soybean variety selection affected the occurrence of insect pests that occurred in the soybean.

Both active (netting) and passive (bee bowls and blue-vane traps) sampling were used to collect the bees, …

Spatial Use By Mammals Within Two State Parks In The Ozarks National Scenic Riverways, Benjamin Aaron Smith

MSU Graduate Theses

A mammalian species inventory with comparisons between sampled sites was conducted via multiple methodologies to document presence of mammals at two Missouri state parks within the Ozark National Scenic Riverways. Camera traps, small mammal traps, acoustic detectors, and mist nets were used to detect species at the parks, and species similarity indices and occupancy analyses were used to discern use of space. A mammalian inventory was compiled for each area of inquiry. Greater diversity was found at the park with more variable habitat types. Bat activity was more in the park with a known hibernaculum, though species specific activity differed …

An Examination Of The Influence Of Multi-Scale Processes And Connectivity On The Population And Assemblage Dynamics Of Headwater Fishes, Josh P. Hubbell

Dissertations

Typified by their branching pattern, headwaters are numerically abundant as the density of these habitats increases with increasing distance from the base of a dendritic river system. Connectivity among headwaters is complex, resulting in the spatial isolation of populations. Headwater specialists have evolved a suite of traits that permit these species to permanently reside within these habitats. The spatial configuration and connectivity of headwaters has repercussions for metapopulations and meta-assemblages. I investigated how multi-scale processes and connectivity influenced the patch occupancy, coexistence, movement ecology, population structure, and gene flow of headwater specialists. In chapter two, I used occupancy modeling to …

Great Lakes Snake: Estimating The Occupancy And Detection Probabilities Of The Eastern Massasauga Rattlesnake (Sistrurus Catenatus), Arin June Thacker

Masters Theses

Detailed knowledge of a species’ range and distribution is important for understanding species persistence and developing species management plans. This issue is particularly pronounced in threatened species with wide-spread range and a low detectability in their natural environment, as surveying and successfully encountering this type of species is oftentimes difficult. One such species is the eastern massasauga rattlesnake (Sistrurus catenatus), a smallbodied pit viper with a distribution centered around the Great Lakes region. We used singleseason occupancy modeling in order to reassess the status of historic massasauga occurrences. We evaluated factors affecting eastern massasauga detection probability from a …

From Phocine Distemper To Avian Influenza: A Study Of Immunogenetic Diversity In Two Sympatric Pinniped Species, Alayna K. Gigliotti

Electronic Theses and Dissertations

Gray (Halichoerus grypus) and harbor (Phoca vitulina) seals are sympatric species that inhabit the North Atlantic and have been subject to mortality events from disease outbreaks, particularly phocine distemper and avian influenza virus. Across mortality events, gray seals tend to exhibit a higher survival rate, which could be explained by various ecological factors impacting rates or direction of selection in parts of the genome related to the immune system. These factors could include haul-out site density, habitat, and degree of inter/intraspecies interaction. This research aims to compare genetic diversity within the Major Histocompatibility Complex (MHC) class …

Assessment Of Wild Ring-Tailed Lemur (Lemur Catta) Populations In Southwestern Madagascar With Implications For The Illegal Pet Trade, Samantha D. Calkins

Theses and Dissertations

Accurate population estimates are critical to inform conservation management of species. Incomplete sampling can lead to population underestimates and lacking conservation efforts. Population surveys are important for assessing human and animal welfare to allow for targeted conservation action. Recent ring-tailed lemur (Lemur catta) surveys have led researchers to conclude that L. catta populations are crashing. This has generated much attention and alarm, but may also be based on incomplete information. To better understand population dynamics, more thorough sampling is needed. Here, we survey five such sites to reassess the presence and abundance of L. catta in these locations. …

Structure And Evolution Of Lizard Immunity Genes, Trent Santonastaso

University of New Orleans Theses and Dissertations

One of the most important gene families to play a role in adaptive immunity is the major histocompatibility complex (MHC). MHC class II loci are considered to be the most variable loci in the vertebrate genome, and studies have shown that this variability can be maintained through complex co-evolutionary dynamics between host and parasite. Despite the rich body of research into the MHC, there is comparatively little understanding of its genomic architecture in reptiles. Similarly, loci associated with innate immunity have received little attention in reptiles compared to other vertebrates. In the first chapter, we investigated the structure and organization …

Documenting West And Central African Dung Beetle (Coleoptera: Scarabaeinae) Community Structures And Their Vulnerability To Climate Change, Christie A. Sukhdeo

University of New Orleans Theses and Dissertations

The Guineo-Congolian (GC) region of West and Central Africa contains high levels of species richness (SR) and endemism. Within the GC region, the Cameroon Volcanic Line (CVL) is an important biodiversity hotspot in part due to montane habitats that constitute important ‘sky islands’ refugia during warm periods of the Pleistocene glacial cycles. However, little is known about the diversity of many taxa in the GC region, especially for insects. The main goals of this dissertation are to: 1) document dung beetle (Coleoptera: Scarabaeinae) species diversity across the GC region and assess the potential impacts of future climate change on species …

Prioritizing The Largest, Oldest Corals For Disease Intervention In A Coral Disease-Ravaged Area: Southeast Florida Coral Reef Ecosystem Conservation Area, Alysha Brunelle

All HCAS Student Capstones, Theses, and Dissertations

Coral diseases appear to be more devastating than ever before. When a virulent disease ravages a coral ecosystem, it can significantly change the population’s demographics and cause local extinctions. Disease intervention response during such an event is impossible at a landscape scale, therefore priorities must be considered. Saving the largest, oldest colonies of reef-building species is a good choice due to their high fecundity and ecological function. Their size, as a proxy for age, is an indicator of their resistance to previous perturbations which may indicate higher fitness. Their size also provides habitat to many organisms and wave resistance in …

Movement And Survival Of Atlantic Salmon Smolts In The Penobscot River, Maine, Alejandro Molina Moctezuma

Electronic Theses and Dissertations

The Penobscot River system hosts the largest population of endangered Atlantic salmon Salmo salar in the United States. However, total adult returns in this river remain low. Historically low numbers led to listing of the distinct population segment (DPS) in 2000, and the Penobscot River population was included in the DPS in 2009. Reducing mortality in all life stages is crucial for the recovery of Atlantic salmon populations. One of the life stages associated to high mortality is the juvenile stage (smolts), in which individuals migrate downstream towards the estuary. During this migration smolts face a series of new conditions …

Patterns And Drivers In Counts Of Migratory Raptors At Hawk Mountain Sanctuary, Usa, Patricia Kaye Tahura Dumandan

Boise State University Theses and Dissertations

Understanding the mechanisms driving biodiversity patterns amidst an era of global environmental change is the core of modern ecological research. The magnitude of biodiversity losses associated with anthropogenic activities has prompted resource managers and ecologists alike to identify strategies to address conservation issues. Broadly, two types of approaches are employed to answer ecological research questions: 1) single-species and 2) ecosystem-based approach. Single-species approaches are often useful to elucidate mechanisms driving population trajectories of individual species. On the other hand, ecosystem-based approaches can help in identifying general patterns that may be useful for multi-species management.

Here, I used both approaches in …

Population Surveys And Health Assessments Of Captive And Free-Ranging Alligator Snapping Turtles, Samantha Louise Hannabass

MSU Graduate Theses

Alligator Snapping Turtles (Macrochelys temminckii) have experienced range-wide declines primarily due to overharvest for the meat market and habitat degradation in the form of damming and channelization of rivers. Head-start programs and reintroduction efforts have been initiated to release individuals throughout their historic range. Before releasing Alligator Snapping Turtles, sites need to be assessed to determine the suitability of habitat, if there is a robust turtle community already present, and the causes of the original extirpation have been eliminated. I assessed the turtle communities and documented anthropogenic impacts (e.g. boat traffic) at nine possible reintroduction sites in southeastern …

Interacting Effects Of Climate And Biotic Factors On Mesocarnivore Distribution And Snowshoe Hare Demography Along The Boreal-Temperate Ecotone, Alexej P. Siren

Doctoral Dissertations

The motivation of my dissertation research was to understand the influence of climate and biotic factors on range limits with a focus on winter-adapted species, including the Canada lynx (Lynx canadensis), American marten (Martes americana), and snowshoe hare (Lepus americanus). I investigated range dynamics along the boreal-temperate ecotone of the northeastern US. Through an integrative literature review, I developed a theoretical framework building from existing thinking on range limits and ecological theory. I used this theory for my second chapter to evaluate direct and indirect causes of carnivore range limits in the northeastern US, …

Autonomous Recording Units As An Alternative Method For Monitoring Songbirds, Lindsay Clough

Masters Theses

There is an increasing interest in the use of autonomous recording units as an alternative survey method to point count surveys conducted by human observers; however, questions remain about whether or not these recording units perform similarly to point count surveys and produce valid, comparable results. The use of individual listeners to transcribe the acoustic data collected by autonomous recording units is a common method for the analysis of recorded acoustic data, but potential variability among transcribers raises questions about the standardization of listening protocols to decrease inconsistencies in transcription results.

Autonomous recording units have been used to monitor birds …

A Macroevolutionary View On Extinction In Aves, Chiroptera, And Odonata, Peter Hasik

Graduate Theses and Dissertations

A central goal of conservation biology is to identify and understand the factors that lead to extinction. The Earth is currently undergoing a 6th mass extinction event, in large part because of human activity. In the last century, rates of extinction have increased anywhere from 8-100 times the background rate of 2 extinctions per 10,000 species every 100 years. However, there remains a debate over whether certain species are predisposed to a higher extinction risk. In particular, it is not known if the macroevolutionary history of a lineage is a major contributor to the probability of extinction, nor is it …

Amount And Sources Of Population Variability In The Metabolome Of A Crayfish Species, Cora Bilhorn

Electronic Thesis and Dissertation Repository

My study investigated the amount of variation associated with region and stream scales in the metabolomes of northern crayfish (Faxonius virilis), collected from seven streams distributed across three ecoregions in Western Canada. Additionally, my study measured metabolomes of crayfish from the same seven streams after experiencing a common laboratory environment to separate the effects of environmental and genetic variation. Region and stream scales were found to be poor predictors of metabolomic variation among crayfish sampled in the field but exhibited increased predictive ability among crayfish exposed to the common environment, indicating crayfish from separate populations responded differently to …

Effects Of Flower Color On Pollination And Seed Production In Lupinus Perennis, Amanda Morris

Honors Projects

We examined how flower color morphs (blue vs white) in Lupinus perennis affect the probability of a flower setting fruit, average mass of a seed produced, and average number of seeds per pod.

Population Genetics Of A Recent Range Expansion By The Southern Pine Beetle, Dendroctonus Frontalis, Into The Northeastern United States, Megan Stubbs

Honors Theses

Population genetics as a field of study aims to determine the genetic variation among individuals in a population, and differences among populations. Certain population genetic analyses can provide such information and be used to better understand the biological aspects to a species’ expansion beyond its native range. The southern pine beetle (SPB), Dendroctonus frontalis, has become an invasive pest to pine forests in northeastern United States with its recent range expansion. Nine microsatellite loci were first developed and then used in analyses. To determine what the genetic variation is among individuals in SPB populations across its entire range, including …

Modeling Species Distribution And Habitat Suitability Of American Ginseng (Panax Quinquefolius) In Virginia, Jacob D. J. Peters

Masters Theses, 2020-current

American ginseng (Panax quinquefolius) is a well-known and sought-after medicinal plant native to North America that is facing increased threat of extinction due to overharvesting, herbivory, and habitat loss. Species distribution and habitat suitability models may be valuable to landowners interested in sustainable harvest or to institutions interested in the conservation and restoration of the species. With unequal sampling efforts across a region of interest, it is likely that some locations with appropriate habitat may be misrepresented in model predictions. This study refined a state-derived species distribution model for ginseng through increased sampling effort across the Cumberland Plateau …

Ecological Analyses Of Macroinvertebrates And Fish Species In Six Streams On A Louisiana Military Base From 2001 To 2019, Danielle Joerger

Biology Theses

An in-depth ecological analysis of how and why the aquatic community changes over time was conducted for 6 streams on the Fort Polk military base in Louisiana using data collected from 2001 to 2019. Fort Polk is a unique location as nineteen first-order streams are located on the premises belonging to three separate drainages. The primary goal was to determine whether temporal or between-drainage variation has a larger effect on community structure. To accomplish this the effects of disturbance on fish and macroinvertebrate assemblages was determined temporally and between drainages. Several hypotheses were drawn from this: 1) temporally, assemblages exhibit …

Chronoecology Of A Cave-Dwelling Orb-Weaver Spider, Meta Ovalis (Araneae: Tetragnathidae), Rebecca Steele

Electronic Theses and Dissertations

Circadian clocks enable coordination of essential biological and metabolic processes in relation to the 24-hour light cycle. However, there are many habitats that are not subject to this light cycle, such as the deep sea, arctic regions, and cave systems. This study analyzes the circadian pattern of isolated populations of a subterranean spider, Meta ovalis from two Tennessee caves and five Indiana caves. Locomotor activity was recorded with TriKinetics LAM50 Locomotor Activity Monitor under a 12-hour light (L), 12-hour dark (D) (LD 12:12) cycle preceding total darkness (DD). Significant differences were found within and among populations found in Tennessee cave …

Patterns Of Genomic Introgression In Topminnow Hybrid Zones, Amanda F. Ray

Honors Theses

Hybridization and introgression are two important evolutionary mechanisms that can increase genetic diversity. Interesting introgression patterns can form when parental species have genes that confer some adaptive benefit to the organism. The Fundulus notatus species complex contains species with various identifying characterisics. Fundulus notatus, the blackstripe topminnow, and Fundulus olivaceus, the blackspotted topminnow, are closely related and occupy many of the same rivers in their preferred niches. These two species often hybridize and form hybrid zones where their niches overlap. We studied two hybrid zones located in the Tombigbee River and Spring River. Within each hybrid zone, we …

Pismo Clams (Tivela Stultorum) In Califorina: Population Status, Habitat Associations, Reproduction, And Growth, Alexandria R. Marquardt

Master's Theses

Marine shellfish play a vital role in intertidal ecosystems and coastal communities, but many of these fisheries are small-scale and lack the necessary monitoring to ensure long-term sustainability. Effective management often requires information on key demographic parameters, such as population status, reproduction and growth. Pismo clams (Tivela stultorum) are a culturally important and iconic species in California, which supported a thriving commercial and recreational fishery throughout much of the 1900’s. However, Pismo clam populations have declined statewide in recent decades and are attributed to human harvest and predation by California sea otters (Enhydra lutris); However, no …