Ecology and Evolutionary Biology Commons^™

From Second Creek To New Pangea: A Multi-Scale Analysis Of Patterns And Trends In Aquatic Biodiversity, Jeffrey Robert Duncan

Doctoral Dissertations

The Earth’s freshwater ecosystems are undergoing a period of dramatic change. The simultaneous expansion and contraction of aquatic species’ ranges is leaving an indelible mark on the evolutionary histories of the world’s freshwater species. This dissertation represents a compilation of research efforts that quantify, explain, and propose policy recommendations concerning current trends in aquatic biodiversity. Part II provides an appraisal of the status of the world’s freshwater fishes that asks two primary questions—are all taxonomic groups equally susceptible to extinction, and can we identify a unifying suite of extinction risk factors? Although I concluded, that extinction risk is not randomly …

The Role Of Water Motion In Algal Reproduction, Richard Gordon

Electronic Theses and Dissertations

Environmental conditions, such as water motion, can influence fertilization success and spore dispersal in marine algae. Previous studies on fucoid algae showed that gamete release is restricted to, or enhanced by, periods of low water motion. Few other algal taxa have been investigated, however, including species with an alternation of generations. I investigated gamete and spore release in the macroalgae Alaria esculenta and Ulva lactuca, as well as in the diatom Pseudo-nitachia multiseries to determine if water motion is inhibitory or stimulates propagule production and release. I used orbital shakers to simulate water motion; these were interspersed with stationary platforms …

Intra- And Inter-Person Variability In Glycemic Responsiveness, Cassandra S. Baldwin

Honors Theses

No abstract provided.

Fine Root Dynamics In Atlantic White Cedar (Chamaecyparis Thyoides) Wetlands: Patterns Of Ecosystem Development In Natural And Restoration Settings, Harvey Leroy Rodgers

Biological Sciences Theses & Dissertations

This work addresses seasonal and successional factors of root dynamics in natural and restoration Atlantic white cedar (AWC) wetlands. Using minirhizotrons, fine root dynamics in a chronosequence of naturally-regenerating and restoration AWC wetlands were measured to compare ecosystem development trends with restoration conditions. A second study was conducted to compare fine root dynamics in AWC wetlands with contrasting hydroperiods. In addition, a technical study was conducted to determine the feasibility of estimating root biomass with indirect minirhizotron measurements.

Root biomass estimates using minirhizotrons were significantly higher in naturally regenerating AWC wetlands and significantly lower in the restoration site relative to …

Chemosensory-Mediated Deposit Feeding In The Spionid Polychaete Dipolydora Quadrilobata., Timothy J. Riordan Jr.

Electronic Theses and Dissertations

Deposit feeding organisms live and feed in marine soft-sediment habitats. This sediment makes up a majority of the material ingested by deposit feeders and contains a variety of edible material that may constitute their principal nutrient source. However, the specific components that are assimilated by these organisms, and the strategies they employ to efficiently collect those components, remain unclear. Sensory interactions between an organism and its surrounding environment typically play an important role in helping the organism detect and locate potential food. Accordingly, chemical sensing by deposit feeders is most likely involved in feeding, yet few specifics about this role …

Anthropogenic Impacts On Riparian Forest Loss In East Tennessee: A Gis Analysis, Karen Burhenn

Masters Theses

Streamside, or riparian, areas are vital components of a healthy watershed system. Natural riparian areas perform multiple ecosystem functions including filtering sediments and pollutants from upland areas, stabilizing banks and floodplains, regulating stream temperatures, and providing habitat for many native and migratory species. In eastern Tennessee, natural riparian forests have declined by 40 to 60 percent (SAMAB 1996b). I examined the spatial distribution of humans and their land-cover changing activities in an effort to contribute to a better understanding of the loss of riparian forests in the eastern Tennessee region.

This research is centered in the Central Ridge and Valley …

Factors Influencing Oviposition Among Pond-Breeding Amphibians: Exotic Vegetation, Oviposition Braces, And Cover, Catherine Mary Callison

Dissertations and Theses

I examined oviposition in four pond-breeding amphibians (northwestern salamander [Ambystoma gracile], long-toed salamander [Ambystoma macrodactylum], Pacific treefrog [Hyla regilla], northern red-legged frog [Rana aurora aurora]), at Burlington Bottoms, a lowland riverine site in northwestern Oregon, to determine whether differential use of native versus exotic plant substrates occurs. I found differential use in all four species, but use was inconsistent with the hypothesis that selection for native plants (or selection against exotic plants) was occurring. If selection was occurring, the pattern implied that reed canarygrass (Phalaris arundinacea), a widespread exotic in this lowland system, was sometimes favored. However, inconsistent use of …

Trichodesmium Spp.: Numerical Studies Of Resource Competition, Carbohydrate Ballasting, And Remote-Sensing Reflectance, Tonya Denise Clayton

OES Theses and Dissertations

In recent years, a new appreciation for the role of diazotrophy in the oceans has emerged. This dissertation reports on three modeling studies designed to investigate ecological processes associated with Trichodesmium spp., the most conspicuous marine diazotroph: (1) characterization of a generalized model Trichodesmium and issues of macronutrient resource competition; (2) carbohydrate ballasting by Trchodesmium and implications for the formation of surface accumulations; and (3) the vertical distribution of Trichodesmium and implications for detection from space.

The first study focuses on issues of nitrogen and phosphorus competition and ecosystem structure. It utilizes a simple ecosystem model that includes dissolved nitrogen …

Systematics Of The Subterranean Amphipod Genus Stygobromus (Crangonyctidae) In Western North America, With Emphasis On Species Of The Hubbsi Group, Daqing Wang

Biological Sciences Theses & Dissertations

This dissertation presents a study of the systematics of the subterranean amphipod genus Stygobromus of family Crangonyctidae in western North America. A total of 53 species of Stygobromus from western North America (including one species from Wisconsin) are recognized, 28 of which are new to science. All species are described and illustrated using external morphological features. A key to the western North America species of Stygobromus is given, as well as a summary of habitats of the species.

Cladistic analyses are conducted using 32 external morphological characters and two categories of outgroup choices: “all-zero” theoretical ancestor and three non-Stygobromus …

Markov Set-Chains As Models Of Plant Succession, Corey L. Samuels

Doctoral Dissertations

In this dissertation I examine Markov set-chains as a new approach for modeling plant succession. Set-chains are an extension of Markov chains, due to Hartfiel (1991, 1998), that makes it possible to model succession when transition probabilities are uncertain or fluctuating. In Markov set-chains each transition probability is expressed as an interval containing the range of all possible values for that parameter. In turn, a set-chain predicts community composition as a range of possible frequencies for each species. First, I give an introduction to Markov set-chains and methods for iterating and finding their asymptotic behavior. I demonstrate the formulation and …

Markov Set-Chains As Models Of Plant Succession, Corey L. Samuels

Doctoral Dissertations

In this dissertation I examine Markov set-chains as a new approach for modeling plant succession. Set-chains are an extension of Markov chains, due to Hartfiel (1991, 1998), that makes it possible to model succession when transition probabilities are uncertain or fluctuating. In Markov set-chains each transition probability is expressed as an interval containing the range of all possible values for that parameter. In turn, a setchain predicts community composition as a range of possible frequencies for each species. First, I give an introduction to Markov set-chains and methods for iterating and finding their asymptotic behavior. I demonstrate the formulation and …

An Ethical Framework For Interpreting The United States Endangered Species Act, Cathryn M. Elgin

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this study I argue that a holistic approach is better than an individualistic approach for interpreting the United States Endangered Species Act (ESA). I propose that the use of a holistic ethical framework, based on fundamental environmental philosophy, is better in that it more effectively fulfills the ESA's goals of species and ecosystem conservation. Holistic ethics is based on concern for a community as a whole, while individualistic ethics is based on concern for the individual. A holistic approach, I argue, is more beneficial to nature than is an individualistic approach or other non-holistic approaches. I set up basic …

Energy, Fractal Movement Patterns, And Scale-Dependent Habitat Relationships Of Urban And Rural Mule Deer, Mark F. Mcclure

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

I studied the behaviors, movement dynamics, habitat relationships, and population characteristics of Rocky Mountain mule deer (Odocoileus hemionus) using urban and rural winter ranges in Cache Valley, Utah, from January 1994 to February 1998. There were 2 goals to my research endeavors. The first was to assess how and why the behaviors and demographic characteristics of urban deer differed from those of rural deer. The second was to assess the scale-dependent responses to habitat and the scale-dependent patterns of habitat use by deer living in each area. To accomplish the first goal, I compared the prevalence of migration, the spatial …

The Response Of First And Second Order Streams To Urban Land-Use In Maine, U.S.A., Chandler Morse

Electronic Theses and Dissertations

Physical, chemical, and biological characteristics of streams draining 20 catchments in Maine, U.S.A were compared to determine the influence of increasing urban intensity on stream ecosystem structure. The catchments had varying levels of urban land-use (percentage of the total impervious area within the catchment) ranging from 1-31%. Stream habitat quality, stability, and water quality consistently decreased as the proportion of impervious surface area increased within the catchment. .Indices based on stream benthic macroinvertebrate communities showed even stronger declines as a function of increasing impervious area in the study catchments. Streams draining catchments with levels of impervious surfaces <6% had higher levels of both total and Ephemeroptera + Plecoptera + Trichoptera (EPT) taxonomic richness. With increased levels of urban intensity, benthic macroinvertebrate communities in streams were characterized by decreased numbers of sensitive taxa. Taxa considered to be moderately sensitive to anthropogenic stress (e.g. Acerpenna (Ephemeroptera), Paracapnia …

Intensification In A Risky Environment: The Case Of Improving Private Grazing Land For Beef Production In Utah, Louise D. Sainsbury

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Utah ranchers commonly face risks to their livelihoods. The objective of this work was to determine if ranchers could make profitable improvements to private land forage given the combined threat of low beef prices, drought, and possible loss of public grazing.

We used linear programming (LINDO) to identify the most profitable solutions for private land investment with an 11-year simulation. Operations were divided into small, medium, and large size classes. Various forage improvements and public permits were options. Two phases of a beef price cycle (peak and trough) and 2 precipitation patterns (wet and drought) were combined as joint favorable …

Morphometric Evaluation Of The Whitefish Complex In Bear Lake, Utah/Idaho, Alan Ward

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Whitefish populations around the world have long been difficult to categorize taxonomically. The whitefish of Bear Lake, Utah/Idaho are no exception. There are three recognized species of Prosopium that are endemic to the lake. Two of these species, Prosopium spilonotus and Prosopium abyssicota, have previously been indistinguishable outside of spawning times. Previous studies have proposed additional taxa within P. spi/onotus to further complicate the identification among these taxa.

Morphological characteristics were quantified on wild whitefish from Bear Lake, as well as from progeny reared in the laboratory from the wild adult fish. The purported taxa were separated in the field …

Ecology Of Treeline Whitebark Pine (Pinus Albicaulis) Populations In Central Idaho: Successional Status, Recruitment, And Mortality, And A Spring Temperature Reconstruction From Whitebark Pine Tree Rings, Dana Lee Perkins

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This research investigated the successional status of treeline whitebark pine (Pinus albicaulis) populations on 14 stands in central Idaho and used empirical statistical models to determine the principal factors affecting recruitment and mortality. The longest lived whitebark pines from four additional high-elevation sites were used to develop a tree-ring chronology to reconstruct over 1,000 years of average April-May temperature.

The assessment of stand structures using size-frequency distributions generally provides evidence that treeline whitebark pine populations are currently self-sustaining in areas of low to nonexistent incidence of white pine blister rust (Cronartium ribicola). However the presence of …

Effectiveness Of Earthen Escape Ramps In Reducing Big Game Mortality In Utah, Mary L. Hammer

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

One-way escape gates and earthen escape ramps are structures used to enable deer to exit the highway right-of-way along fenced roads. I compared the use of one-way escape gates and earthen escape ramps by mule deer on two highways in Utah to determine if deer exhibited a preference for either structure. Results showed that earthen escape ramps were used by mule deer 8-11 times more frequently than one-way gates. Highway mortality data suggest that the installation of the escape ramps likely reduced mortality of mule deer in both study locations, because we could not attribute reductions in mortality to decreased …

Attitudes And Practices About Weight, Weight Management, And The Association Of These Factors With The Development Of Chronic Disease In A Convenience Sample Of Dietetics Students, Karah Lynnette Lindbergh

Honors Theses

No abstract provided.

Comparison Of Rodent Communities Of Native Brushland, Replanted, And Secondary Succession Sites In The Lower Rio Grande Valley Of Texas, Mitchell Allen Sternberg

Theses and Dissertations - UTB/UTPA

I compared small mammal communities between mature brushlands, replanted brushlands, and secondary succession sites from November 1998 to December 1999 to evaluate revegetation efforts in the Lower Rio Grande Valley of Texas. I determined rodent community characteristics of the three habitat types. The mature brushland and replanted habitats had similar species diversities and both were significantly higher than the secondary succession habitat. Species diversity was highest at the replanted edge grid during Winter. The current replanting method provides a more diverse rodent community than does natural succession from fallow fields. Wildlife monitoring should be extended to other taxonomic guilds so …

Patterns Of Avian Productivity Indices At Santa Ana National Wildlife Refuge (1995–1999), Tina Louise Gallegos

Theses and Dissertations - UTB/UTPA

I examined demographic parameters at Santa Ana National Wildlife Refuge, 1995–1999 utilizing Monitoring Avian Productivity and Survivorship protocol. The Olive Sparrow was the species most frequently captured. The capture rate of adult and young birds remained fairly steady over the years and no significant linear trends were observed. Productivity was highest in 1997, which influenced the number of adults captured in 1998, and was significantly related to annual rainfall. Mean total capture rates were higher at the Highland station than the Resaca station. Demographic comparisons between mist nets and point counts were variable, suggesting that both sampling techniques have their …

Effects Of Human Disturbances On The Behavior Of Dabbling Ducks, Melissa Lynn Pease

Biological Sciences Theses & Dissertations

Disturbance of wintering and migrating birds by human activities can cause birds to expend energy in avoidance of humans and reduces the time available for resting and feeding at a time in the annual cycle when fat deposition and energy conservation are important. Also, human disturbances can effectively cause habitat loss by displacing birds from feeding or resting habitat. Managers of natural resources are increasingly faced with decisions about the types and amounts of public use that should be allowed without lowering the value of the resource for wildlife. In order for managers to make decisions about how to minimize …

The Implications Of The Target-Area Hypothesis On The Population Dynamics Of The Spotted Spiny Lobster, Panulirus Guttatus, Denice N. Robertson

Biological Sciences Theses & Dissertations

The target-area hypothesis, based on the theory of island biogeography, predicts that larger islands are more effective at intercepting passive immigrants. Most marine invertebrates have meroplanktonic larvae and open population dynamics, so immigration to populations in isolated benthic habitats is primarily by pelagic larval recruits. Thus, recruitment to isolated habitat “islands” may be more continuous and predictable on large islands than on small ones. Consequently, populations on large islands should not only be larger than those on small islands, but should also have more evenly distributed size structures. These differences in size structure among populations in isolated habitats of differing …

A Comparison Of Phytoplankton Communities In Lake Prince And The Western Branch Reservoir, Suffolk, Virginia, Cara Marie Muscio

Biological Sciences Theses & Dissertations

Lake Prince and the Western Branch Reservoir are two eutrophic bodies of water located in Suffolk, Virginia. Lake Prince and its two small tributaries join the Western branch via a constructed spillway. This lake system is a source of water for the surrounding municipalities, and a recreational area for community citizens. In the past, these bodies of water had repeated incidents of low oxygen and nuisance algal blooms, particularly cyanobacteria species. As a result aerators have been installed in the main body of both Lake Prince and the Western Branch Reservoir. In addition, a pipeline has been installed from North …

The Effect Of Nitrogen Fertilization On Short-Term Fine Root Dynamics In A Barrier Island Dune Community, John Walter Hutton

Biological Sciences Theses & Dissertations

Fine root dynamics are an important yet poorly understood component of terrestrial ecosystems. In recent years a number of researchers have focused on fine root dynamics; their work has looked at patterns across one or multiple growing seasons on a scale of monthly measures. The purpose of this study was to add to the overall understanding by looking at fine root dynamics on a shorter temporal scale. Minirhizotron observation tubes were used to assess the effect of nitrogen fertilization on short-term fine root dynamics in a nutrient limited, barrier island dune system. Root length elongation and mortality rates followed expected …

In Support Of A Rationally Managed Fishery: Age And Growth In Patagonian Toothfish (Dissostichus Eleginoides), Julian R. Ashford

Biological Sciences Theses & Dissertations

Patagonian toothfish (Dissostichus eleginoides) occur on the continental shelves and shelf breaks of southern South America and the Southern Ocean. Stock structure, critical to good fisheries management, can be inferred from growth differences between areas, but available growth data are compromised by inconsistencies in age estimation methods, sampling and sample sizes, and techniques used to derive estimates. I asked the scientific question: how is growth in Patagonian toothfish structured spatially within the Southern Ocean? I developed a multi-stage randomized design to sample fish caught by commercial longline, and an age estimation methodology. Because toothfish are difficult to age, …

Seasonal Phytoplankton Assemblages Of Five Ephemeral Ponds In York County, Virginia, Michelle R. Kokolis

Biological Sciences Theses & Dissertations

Five ephemeral ponds were identified in and around the Grafton Ponds Natural Area Preserve, approximately 56 km north of the City of Norfolk, Virginia. These ponds, which are filled seasonally by precipitation and groundwater discharge, range from 0.1 ha to 2 ha in size and from 4 cm to 3 meters in depth. Ponds for the study were chosen based on variations in their size, depth, basin cover material, canopy openness, and historical inundation period. The purpose of this study is to relate differences in the phytoplankton assemblages to the physical and chemical characteristics of the ponds. All five ponds …

Natural Succession Of Benthic Populations In Constructed Sediment Ponds And Ditches In Southwestern West Virginia, Robin E. Dolin

Theses, Dissertations and Capstones

Strip mining causes major disturbances of the natural environment. One such disturbance is the creation of valley fills, which often fill in the headwaters of small streams. Runoff from these valley fills can cause heavy siltation as well as acid and heavy metal deposition downstream. One way to combat this problem is through the construction of sedimentation ponds, which slow down the flow of water so that sediment can settle out and water chemistry can be altered before the water is discharged into the stream. Since these ponds are, in effect, temporarily replacing small headwaters once present, the question is …

Factors Influencing Spatial Variability In Soil Nitrogen (N) Dynamics In N-Treated And Untreated Watersheds Of The Fernow Experimental Forest, West Virginia, Nikki Lenore Lyttle

Theses, Dissertations and Capstones

The central Appalachian region of the United States receives some of the highest inputs of nitrogen (N) due to acidic deposition in the nation. It is believed that these high could levels contribute to a decline in forest soils within the next 50 to 70 yrs. This study examines factors that influence spatial variability in N-treated and untreated watersheds of the Fernow Experimental Forest, Parsons, West Virginia. Within each of the two watersheds [WS4 untreated control, > 100 yr.; WS3 N-treated, acidified, clear cut, ~ 31 yr.], two 0.04 ha plots, one high N and one low N, were selected for …

Development Of Geobiophysical Models For Cartographic Representation Of Wetlands In Yellow Creek Basin, West Virginia, Ian Farrar

Theses, Dissertations and Capstones

In the Appalachian Mountains of Canaan Valley, the warmer temperatures and fading native species are conducive for invading foreign species. Localized relic communities of red spruce, sphagnum and polytrichum are sensitive to climatic change and potential indicators of global warming. Therefore, the development of a baseline assessment and further research are necessary to observe and model changes. Influencing factors in wetland ecology include slope, aspect, biologically rich and diverse vegetation associations, micro-topography, hydrology, underlying soils, and geology. Three uniquely independent study sites have been established along a single transect of the Yellow Creek stream terraces, in Tucker County, West Virginia. …