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The Tangled Web Of Community Ecology: Making Sense Of Complex Data, Monica Lynn Beals

Doctoral Dissertations

Ecological communities are governed by complicated processes that give rise to observable patterns. Making sense of these patterns, much less inferring the underlying processes, has proved challenging for several reasons. Manipulative experiments in natural communities may not be feasible due to large numbers of variables, lack of adequate replication, or the risk of undesirable consequences (e.g., introducing an invasive species). The multivariate nature of ecological datasets presents analytical problems as well; many statistical techniques familiar to ecologists have difficulty handling large numbers of potentially collinear variables. I present results from three studies of spider communities in which I employ a …

Avian Community Ecology: Patterns Of Co-Occurrence, Nestedness, And Morphology, Michael David Collins

Doctoral Dissertations

A central tenet of the competition paradigm is that community structure is governed by deterministic rules. The competition paradigm pervades nearly all subdisciplines and extends to the broadest, deepest questions in ecology. To determine whether patterns of co-occurrence, nestedness, and morphology in avian communities are consistent with a competition hypothesis, I use null models to compare observed patterns to patterns expected in the absence of competition.

I use presence-absence matrices of birds in three archipelagoes to test whether species exhibit exclusive distributions. Congeneric birds co-occur significantly less frequently than predicted in two archipelagoes, consistent with a competition hypothesis. However, when …

Insights Into The Etheostoma Spectabile Species Complex: Incongruence Between Mitochondrial And Nuclear Gene Sequence Data, Christen M. Bossu

Masters Theses

Hybridization is recognized as an evolutionary process that can provide a significant source of genetic variation and whose genetic consequences have been investigated across a wide taxonomic range of plants and animals. Darters (Percidae: Etheostomatinae) are a clade with documented interspecific hybridization and many species with a recent evolutionary origin, yet most molecular phylogenetic analyses of darters to date have relied primarily on mitochondrial DNA (mtDNA) sequences. Inferring relationships within and between closely related species using a single locus gene tree is potentially confounded by introgression as well as retention of ancestral polymorphisms. This can lead to incongruence between the …

Multiscale Habitat Associations Of Three Primary Burrowing Crayfish, Shane Welch

All Dissertations

The distribution and habitat associations of three primary burrowing crayfish species were examined at the landscape and patch scales. GIS based predictors were used to model the species occurrence across the study landscapes and vegetation structure data were used to model crayfish abundance within landscape patches. Distocambarus crockeri, a species endemic to the piedmont physiographic region of South Carolina was a terrestrial habitat specialist at broad because of its association with well drained ridge-top soils. Within these soils D. crockeri were dependent on open treeless habitats. The species habitat was consistent with early descriptions of the region and suggested that …

Determining Environmental Drivers Of Fish Community Structure Along The Coast Of Maine, Adrian Jordaan

Electronic Theses and Dissertations

The work presented here was conceived to determine whether structure in marine communities could be related to multiple scaled environmental parameters, as seen in lake and stream systems. Four datasets collected from 2001 to 2005 were used. The datasets ranged from local scale tidepool and estuarine surveys, to more regional intertidal/subtidal surveys and conclude using a coast-wide trawl survey. Initially, a bootstrap program for running principal component analysis (PCA) was developed and tested for utility with additional information from Pearson correlation coefficients. The bootstrap-PC A program was capable of determining confidence limits for correlations amongst species. The results from analysis …

The Effects Of Pathogen Infection On Nitrogen Remobilization In Arabidopsis Thaliana, Michelle Ann Boercker

Masters Theses

The natural enemies of plants are ubiquitous and can reduce plant fitness. Plants have evolved two defense strategies to ameliorate the fitness cost associated with natural enemy attack. The first strategy, resistance, reduces the frequency and/or severity of natural enemy damage. The second strategy, tolerance, attenuates the fitness cost of natural enemy damage. Very little is known about the traits through which tolerance is manifested, particularly with respect to plant-pathogen systems (pathosystems). Diseased and naturally senescing leaves are often similar in their visible symptoms and molecular activities, suggesting that they may involve similar processes. One process that may be shared …

Vertical Export Of Biogenic Matter In The Chukchi And Barents Seas, Catherine Lalande

Doctoral Dissertations

Drifting sediment traps were deployed in 2004 in the ChukchiSeato investigate the variability in the vertical flux of biogenic matter in the presence and absence of sea ice. Measurements of chlorophyll-a, particulate organic carbon (POC), particulate organic nitrogen, phytoplankton, zooplankton fecal pellets, and the stable carbon isotope composition of the sinking material were accomplished along two shelf-to-basin transects. POC fluxes obtained in ice-covered and ice-free conditions were of different composition but of similar magnitude, indicating that the export fluxes in the presence of ice cover contributed significantly to the annual export of biogenic matter in the Chukchi Sea. …

Explaining Species Diversity By Linking Local And Large Scale Processes, Marc William Cadotte

Doctoral Dissertations

Large-scale processes are known to be important for patterns of species richness, yet the ways in which local and larger scale processes interact is not clear. I first examined published experiments that manipulated dispersal among local communities using meta- analyses. I show that local communities often readily increase diversity, but that there may be declines at larger spatial scales. I then used metacommunities consisting of microbial aquatic communities to examine how processes at different scales affect local and metacommunity richness. Specifically, I manipulated the potential dispersal rate, whether dispersal was localized or global, and variation in initial community composition. I …

Physical And Behavioral Development Of Nursing Harbor Seal (Phoca Vitulina) Pups In Maine, John P. Skinner

Electronic Theses and Dissertations

Compared to other phocids seals, the maternal investment strategy of the small bodied female harbor seal (Phoca vitulina) is complex. Females are unable to fast for the entire duration of pup rearing and are therefore reliant on resources in the vicinity of the pupping aggregation to continue provisioning their pup by mid-lactation. At the same time, harbor seal pups are highly active during lactation which increases energetic costs to the female but also offers an opportunity for females to influence the behavioral development of her pup. To understand how females maximize their pup's survival it is important to …

Ecological Relationships Among Partial Harvesting, Vegetation, Snowshoe Hares, And Canada Lynx In Maine, Laura Robinson

Electronic Theses and Dissertations

Understanding the ecological factors affecting habitat use by the Canada lynx (Lynx canadensis) and its primary prey, the snowshoe hare (Lepus americanus), could help formulate conservation strategies for this carnivore, which is federally listed as threatened and occurs in only four regions of the U.S.A. I measured vegetation characteristics and snowshoe hare densities in 15 regenerating conifer clearcuts and 21 partially harvested stands in northern Maine during the leaf-off seasons, 2005 and 2006; and the leaf-on season, 2005. Regenerating clearcut stands had been harvested between 1974 and 1985 and were subsequently treated with an aerial application …

A Shelf-To-Basin Examination Of Food Supply For Arctic Benthic Macrofauna And The Potential Biases Of Sampling Methodology, Rebecca Pirtle-Levy

Masters Theses

Macrofaunal samples (benthic fauna) and sediment samples were collected in association with the sampling programs of the Bering Strait Environmental Observatory (BSEO; Cooper et al. 2006, see http://arctic.bio.utk.edu/) during the summer of 2003 and 2004 and the Western Arctic Shelf-Basin Interactions (SBI; Grebmeier and Harvey 2005, see http://sbi.utk.edu for further information) during the spring (May-June) and summer (July-August) of 2004. Benthic measurements of sediment chlorophyll a, grain size, total organic carbon, C/N ratios, and macroinfaunal community composition were measured on the shelf, slope and basin of the region. The current study focuses on sediment chlorophyll a inventories of surface …

A Test Of The Enemy Release Hypothesis Using A Congeneric Pair Of Lespedeza Species, Mary Gail Caflisch

Masters Theses

The enemy release hypothesis (ERH) postulates that invasive species are released from the effects of the herbivores, predators, pathogens, and other enemies that control population sizes in the native ranges of the invasive species. In a one-year common garden experiment, I compared the native species Lespedeza capitata to the invasive species Lespedeza cuneata. I examined relative fitness and performance over the first growing season and manipulated arthropod abundance using insecticide applications. While L. capitata had higher germination and survivorship than did L. cuneata, it also sustained more natural enemy damage. Arthropod reduction increased height and apparent survivorship for L. capitata. …

Chironomid Hemoglobin Genetic Diversity As An Indicator Of The New Jersey Hackensack Meadowlands Wetland Health, Lene Marie De Coursin Jacobs

Seton Hall University Dissertations and Theses (ETDs)

Kearny Marsh located within the Hackensack Meadowlands is a freshwater wetland impacted by multiple environmental stressors from human activity. The marsh is located in the northeastern New Jersey metropolitan area. Chironomid larvae, aquatic larvae of midge fly, were analyzed from two Kearny Marsh sample sites, W9 and W22. A previous sediment analysis and toxicity study characterized heavy metal contaminants the marsh. The data results were applied in this thesis study to determine the correlation between environmental stressors and chironomid genetic diversity. Site W9 sediment was impacted by severe levels of total heavy metal contamination, whereas site W22 had just below …

Chemical Evidence For Dietary Toxin Sequestration In The Asian Snake Rhabdophis Tigrinus, Deborah A. Hutchinson

Biological Sciences Theses & Dissertations

Rhabdophis tigrinus (Colubridae: Natricinae) is an oviparous, bufophagous (toad-eating) snake from eastern Asia that possesses defensive integumentary glands on the neck known as nuchal glands. These glands are used in antipredator displays and typically contain bufadienolide toxins. Whereas toads are known to synthesize bufadienolide steroids from cholesterol precursors, we found that chemically undefended R. tigrinus must sequester bufadienolides from ingested toads in order to exhibit these compounds in their nuchal glands. Chemically defended females are capable of provisioning their embryos with these toxins so their unfed hatchlings possess defensive bufadienolides prior to consuming toads themselves. All of the hatchling R. …

Odonates At The Clark County Wetlands Nature Preserve: A Look At Habitat And Relative Abundance, Erin Jolley

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study is to identify the various species, relative abundance and habitat of dragonfly and damselfly larvae at the Clark County Wetlands Park Nature Preserve (WPNP). An accurate assessment of these insects can be useful in interpreting potential indications of environmental problems at the Wetlands. From this data, necessary improvements can be made to the dragonfly habitat as well as the habitat of other surrounding organisms. Habitat identification is considered especially important because it is "structured by instream and surrounding topographical features, and is a major determinant of aquatic community potential" (Southwood, 1977). For purposes of this …

Calcium Intake, Bone Mineral Density, And Percent Body Fat Of University Students, Beth Peterson

Honors Theses

No abstract provided.

The Contribution Of Environmental Variables On Small Mammal Species Richness And Relative Abundance In Eastern Nevada, Stephanie Harris

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study is to determine how four environmental variables: elevation, latitude, soil type, and vegetation impact the relative abundance of Peromyscus maniculatus and the species richness of small mammal populations in Eastern Nevada. In order to complete this study, a survey of small mammals was completed in the following 8 Eastern Nevada valleys: Delamar, Dry Lake, Dry Lake- Muleshoe,Cave, Lake, Snake, Spring, White River. In each valley, transects of Sherman live traps will be set up for 3 consecutive nights (O'Farrell et al 1977). Data on elevation, latitude, soil type, and vegetation were taken at each trap …

The Fate And Transport Of Nitrogen (N) And The Effect Of Emergent Plants On Natural Treatment Of N-Species At Las Vegas Wash, Nevada, Tanju Kiriscioglu

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study is to analyze the effect of emergent plant communities at Las Vegas Wash (the System) using a system dynamics modeling approach. Understanding the dynamics of nitrogen (N —major polluting nutrient in the Wash) that enters the System is important because it occasionally causes algal blooms, choking Lake Mead through excessive eutrophication. Emergent plant communities are an integral part of wetland ecosystems and they play a crucial role in natural treatment of nutrients. This study is intended to test this hypothesis.

The study makes use of Wash data from reliable sources (Las Vegas Valley Water District, …

Population Trends Of Wintering Bald Eagles (Haliaeetus Leucocephalus) At The Lake Mead National Recreation Area, Nevada, Deanna Morrell

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to look at population trends of wintering bald eagles (Haliaeetus leucocephalus) at the Lake Mead National Recreation Area, Nevada from 1991 to 2006. Bald eagles were counted on January 5, 2006 along the entire shoreline of Lake Mead and Lake Mohave. This study focused on two questions: (1) how has the population changed over time? (2) How has the proportion of juvenile eagles to adult eagles changed over time? Question one was supported with the number of bald eagles significantly increasing (r=0.76, p=0.002). Question two was supported as the proportion of juveniles to adults …

Applying Landscape-Scale Modeling To Everglades Restoration, Scott M. Duke-Sylvester

Doctoral Dissertations

In this dissertation I describe the implementation and application of three spatially-explicit, landscape-scale models designed to address specific aspects of Everglades restoration. The first is a model of vegetation succession for the Everglades. The second is a fire model for the Everglades. The third is a model of the spread and optimal spatial control of an invasive, non-native plant.

I developed the succession and fire models as part of the Across Trophic Level System Simulation (ATLSS). These models are used to assess the relative effects of alternative hydrology scenarios on the distribution of vegetation and fires. In addition to the …

Remapping The Cliff Chipmunk (Neotamias Dorsalis) Distribution And Creating A Habitat Association Model In Southern Idaho, Masako Niwa

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The distribution of the cliff chipmunk in Idaho was previously considered to include only the Raft River Valley and the Goose Creek Basin. A pilot study was conducted in 2003 and 2004. Thirty-five cliff chipmunk presence locations and 124 absence locations were recorded. Habitat variables of elevation, slope, deviation from south, distance to water, and vegetation type were extracted for all of the absence and presence points by means of GIS analysis. The data were analyzed by implementing a classification tree, and a "GIS habitat association model" was created. The model was tested in 2005, and the overall model accuracy …

Comparative Pollen Foraging Of Africanized And European Honeybees In A Non-Agricultural Environment, Ruben Ruiz

Theses and Dissertations - UTB/UTPA

With the advent of the Africanized honeybee, ways to differentiate it from the European honeybee have been greatly sought in attempts to better understand the role of Africanized bees in pollination. Pollen collecting strategies for both honeybee subspecies have been explored in attempts to exploit their pollinating capabilities. This project examined pollen collected by honeybees from feral and managed European and Africanized colonies in a relatively isolated site. Paired European and Africanized honeybee colonies were used to obtain pollen foragers. Through acetolysis (series acidified Acetic Anhydride washings); the collected pollen from the individual foragers was treated and observed with light …

Survey Of The Great Kanawha River, West Virginia, For Virulence Related Gene Markers Stx1, Stx2, And Eaea, Christina Carole Johnson

Theses, Dissertations and Capstones

Microbial surveying using antibiotic resistant bacteria, fecal coliforms, and virulence genes is an approach not previously tested on the Great Kanawha River. Research objectives were to test antibiotic resistant and fecal coliform bacteria as bioindicators of water quality, and develop a multiplex- polymerase chain reaction (mPCR) system for identification of stx1, stx2, and eaeA DNA sequences in isolated fecal coliforms (FC). Fecal indicator populations and antibiotic resistant populations were demonstrated to be independent. Bacterial populations were assigned impact score(s) (IS) values for each sample site based on data set percent ranks. Population scores were summed per sample site to generate …

The Breeding Ecology And Natural History Of Ambystomatid Salamanders In An Ephemeral Wetland In Mason County, West Virginia, S. Douglas Kaylor

Theses, Dissertations and Capstones

A forested ephemeral wetland in Mason County, WV, documented to contain 4 of 5 Ambystoma species found in the state, was studied to learn about population sizes, breeding cycles, and habitat use. Minnow traps were placed along three drift fences with additional traps placed throughout the study area. From February 5 to March 27, 2005, 85 captured adults were identified to species, marked by elastomer injection for mark-recapture analysis, and measured for morphometrics. Larval salamanders were identified, staged, measured, and returned. Egg clutches were mapped and counted. Mark-recapture analysis suggests the A. texanum population size is between 635 and 735 …

Natural History And Distribution Of The Upland Chorus Frog, Pseudacris Feriarum Baird, In West Virginia, Jaime Sias

Theses, Dissertations and Capstones

Chapter 1 is a literature review of Pseudacris feriarum, largely based on published P. triseriata Complex species accounts. Chapter 2 presents the natural history of P. feriarum in West Virginia and compares some parameters with other Pseudacris species. Chapter 3 looks at the phenology of a wetland in eastern West Virginia. Chapter 4 examines the current range of P. feriarum and compares it with the historical range in the state. Finally, hypotheses are given as to why Upland Chorus Frogs have declined in West Virginia. All information obtained from this study should be used to create a management plan for …

The Natural History And Thermal Ecology Of A Population Of Spotted Turtles (Clemmys Guttata) And Wood Turtles (Glyptemys Insculpta) In West Virginia, Ariana N. Breisch

Theses, Dissertations and Capstones

An ecological study was conducted from 19 March 2001 to 2 April 2003 on a population of Spotted Turtles (Clemmys guttata) and Wood Turtles (Glyptemys insculpta) in West Virginia. Live-trapping, mark-recapture, radio telemetry and temperature data logging techniques were used to gather information on morphometrics, capture success, movements, home range, behavior, and thermal regime during activity and over-wintering seasons. Twenty-one Spotted Turtles were captured 260 times. Population structure was 42.9% juvenile, 38.1% male, and 19.0% female. Mean home range was 0.52 ha. Fifty Wood Turtles were captured 230 times. Juveniles were 36%, and males and females were 32% each. Mean …

Constructed Ponds As Mitigated Habitat For The Wood Frog (Rana Sylvatica Leconte) And The Spotted Salamander (Ambystoma Maculatum Shaw) In West Virginia, Celeste Dawn Good

Theses, Dissertations and Capstones

Many forest dwelling amphibians depend upon aquatic breeding habitats, making them susceptible to habitat changes. To determine if amphibian use of temporary pools occurred, 9 ponds were constructed in 3 forested areas on the MeadWestvaco Wildlife and Ecosystem Research Forest. Studies were conducted in 6 ponds during 2004, and all 9 in 2005 using drift fences. Trapped amphibians were measured and given a pond specific mark with visible implant elastomers. A significant difference was found between low and high elevation sites for juvenile R. sylvatica snout-to-vent length. No significant differences were found for soil, air or water temperatures between sites …

Population Genetics And Phylogeography Of The Pygmy Nuthatch In Southern California, Thomas Alan Benson

Theses Digitization Project

Uses mitochondrial DNA sequence data to examine the degree of genetic differentiation among sky island populations of two subspecies of pygmy nuthatch (Sitta pygmaea melanotis and Sitta pygmaea leuconucha) occurring in Southern California. Assesses the hypothesis that sky islands are genetically isolated and that migration (gene flow) is restricted among them. Eleven sampling locations throughout Southern California were selected based on representation of subspecies, availability of specimens, and feasibility of collection. Results indicate that pygmy nuthatch populations fragmented in the disjunct mountain ranges of Southern California exhibit low but significant levels of genetic differentiation.

The Influence Of Predation On The Nesting Ecology Of Diamondback Terrapins (Malaclemys Terrapin) In The Lower Chesapeake Bay, Victoria Ann Ruzicka

Dissertations, Theses, and Masters Projects

No abstract provided.

Drying And Re-Wetting Of Organic Wetland Sediments: Biogeochemistry And Implications For Wetland Management, Beate Sommer

Theses: Doctorates and Masters

In the past decade, increasing instances of eutrophication and acidification of wetlands on the Swan Coastal Plain (SCP), Western Australia, and particularly on the Gnangara groundwater mound, have coincided with gradually decreasing ground- and surface water levels. The processes involved in determining whether a wetland will acidify or become eutrophic (or both) as a result of drawdown are still poorly understood, especially on the SCP where there are strong links between wetland water quality and underlying geomorphology. For instance, many of the wetlands located on the wellbuffered geomorphic unit called the Spearwood dunes are eutrophic due to high nutrient loads, …