Open Access. Powered by Scholars. Published by Universities.®

Ecology and Evolutionary Biology Commons™

Open Access. Powered by Scholars. Published by Universities.®

University of Arkansas, Fayetteville

Discipline
Keyword
Publication Year
Publication
Publication Type

Articles 211 - 240 of 632

Full-Text Articles in Ecology and Evolutionary Biology

Validation Of The Use Of Doubly Labeled Water For Measuring Metabolic Rate In Timber Rattlesnakes (Crotalus Horridus), Caitlin Hirsh May 2016

Validation Of The Use Of Doubly Labeled Water For Measuring Metabolic Rate In Timber Rattlesnakes (Crotalus Horridus), Caitlin Hirsh

Biological Sciences Undergraduate Honors Theses

The doubly labeled water method is an isotopic technique for measuring field metabolic rate and water flux rates of free-living animals. We present a validation of the use doubly labeled water for measuring metabolic rate and water loss in Timber Rattlesnakes (Crotalus horridus). For this study seven animals of varying body size were used with masses ranging from 148 to 650 grams. Prior to dosing, blood samples were taken to establish background isotope levels for each animal. Snakes were injected with water enriched with isotopes of oxygen (18O) and hydrogen (2H, deuterium). The injected isotopes were then allowed to equilibrate …

Go to article

Response Of Leukocyte Profiles To Corticosterone Manipulation In The Prairie Rattlesnake (Crotalus Viridus), Jill E. Guillette May 2016

Response Of Leukocyte Profiles To Corticosterone Manipulation In The Prairie Rattlesnake (Crotalus Viridus), Jill E. Guillette

Biological Sciences Undergraduate Honors Theses

Prior work has shown that when animals are stressed they have altered leukocyte profiles. The use of leukocyte profiles could provide an inexpensive and efficient method for determining stress. Here we present a validation of the use of leukocyte profiles for showing induced stress in Prairie Rattlesnakes (Crotalus viridus). Snakes (N=19) with masses ranging from 682g to 137g were used in a repeated measures design to examine the effect of hormone manipulation on leukocyte profiles. During each trial snakes were dosed with either corticosterone and sesame oil (1.1µg/g) or only sesame oil. Prior to dosing, baseline blood samples …

Go to article

Emergence Phenology And Nematode Associates Of The Woodwasp, Sirex Nigricornis F. (Hymenoptera: Siricidae), In Arkansas And Mississippi Forests, Jessica Ann Hartshorn May 2016

Emergence Phenology And Nematode Associates Of The Woodwasp, Sirex Nigricornis F. (Hymenoptera: Siricidae), In Arkansas And Mississippi Forests, Jessica Ann Hartshorn

Graduate Theses and Dissertations

Sirex nigricornis F. (Hymenoptera: Siricidae) is a native woodwasp in eastern North America that inhabits dead and dying pine trees during its univoltine development. Sirex noctilio is native to Eurasia and North Africa and was discovered in the northeastern United States in 2004 after a century of accidental introductions across the Southern Hemisphere. Since then, it has spread to seven states and southern Ontario. There is concern about its potential to negatively affect the multi-billion dollar pine timber industry of the southeastern United States. Effective monitoring tools are necessary to track the spread and establishment of S. noctilio. Deladenus siricidicola …

Go to article

Dietary Effects On The Stoichiometry Of Growth, Regulation, And Wastes Of Ozark Stream Insect Detritivores, Halvor Matthew Halvorson May 2016

Dietary Effects On The Stoichiometry Of Growth, Regulation, And Wastes Of Ozark Stream Insect Detritivores, Halvor Matthew Halvorson

Graduate Theses and Dissertations

A widespread stressor, anthropogenic nitrogen (N) and phosphorus (P) pollution can increase resource nutrient content and alter animal community composition in freshwater ecosystems. In this dissertation, I used ecological stoichiometry theory to examine effects of diet nutrient content and leaf litter type on growth, regulation, and wastes of aquatic invertebrate detritivores. I tested effects of leaf litter diet carbon:phosphorus (C:P) on growth and stoichiometric regulation of the detritivorous caddisfly Pycnopsyche lepida and used results to determine a threshold elemental ratio of oak litter C:P=1620 that confers peak growth of this species. This empirical, growth-based approach provided a more accurate estimate …

Go to article

[Re]Visiting The Rime: A Case Study Of Adaptation As Process And Product With The Rime Of The Ancient Mariner, Sally Ferguson May 2016

[Re]Visiting The Rime: A Case Study Of Adaptation As Process And Product With The Rime Of The Ancient Mariner, Sally Ferguson

Graduate Theses and Dissertations

This thesis combines adaptation theory with ecology to examine Samuel Taylor Coleridge's Rime of the Ancient Mariner (1798) and its adaptations; it argues further combinations of adaptation with evolutionary theory and ecological ideas could allow for a better interpretation of many texts. The adaptation Rime of the Modern Mariner (2011) by Nick Hayes and the appropriation Perelandra (1943) by C.S. Lewis will also be present in individual chapters to examine the texts' interactions with each other as they evolve and how each work represents the combined theory.

Go to article

Responses Of Semi-Aquatic Snakes To Drought, Philip Nicholas Vogrinc May 2016

Responses Of Semi-Aquatic Snakes To Drought, Philip Nicholas Vogrinc

Graduate Theses and Dissertations

Aquatic ecosystems and their associated wildlife are threatened by alteration in the frequency and intensity of precipitation events predicted to affect many regions as a consequence of global climate change. Semi-aquatic snakes serve important roles as predators and prey within aquatic ecosystems, yet little is known about the effects of drought on these species due to their secretive behavior. Long-term studies at an isolated wetland in South Carolina found that drought caused populations of banded watersnakes (Nerodia fasciata) and Florida green watersnakes (Nerodia floridana) to crash. Alternatively, black swamp snakes (Seminatrix pygaea) fared well, exhibiting a resistance strategy by aestivating …

Go to article

The Role Of Hydrologic Regimes In Driving Morphologic Divergence And The Trait Compositions Of Fish Assemblages, Lindsey A. Bruckerhoff May 2016

The Role Of Hydrologic Regimes In Driving Morphologic Divergence And The Trait Compositions Of Fish Assemblages, Lindsey A. Bruckerhoff

Graduate Theses and Dissertations

The hydrologic regime is an important determinant of the ecological integrity of a stream. Hydrologic regimes are defined by the magnitude, timing, frequency, rate of change, and duration of high and low flow events and capture long term patterns of variability and predictability of water movement in a stream. Flow regimes influence many aspects of the biophysical environment in lotic systems; therefore organisms have adapted to natural flow patterns. We investigated how fish have adapted to flow regimes at both a population and community level. In the first study presented in this thesis, we hypothesized fish exhibit phenotypic divergence to …

Go to article

Upscaling Methane Emission Hotspots In Boreal Peatlands, Fabio Cresto Aleina, Benjamin R. K. Runkle, Tim Brucher, Thomas Kleinen, Victor Brovkin Mar 2016

Upscaling Methane Emission Hotspots In Boreal Peatlands, Fabio Cresto Aleina, Benjamin R. K. Runkle, Tim Brucher, Thomas Kleinen, Victor Brovkin

Biological and Agricultural Engineering Faculty Publications and Presentations

Upscaling the properties and effects of small-scale surface heterogeneities to larger scales is a challenging issue in land surface modeling. We developed a novel approach to upscale local methane emissions in a boreal peatland from the micro-topographic scale to the landscape scale. We based this new parameterization on the analysis of the water table pattern generated by the Hummock–Hollow model, a microtopography resolving model for peatland hydrology. We introduce this parameterization of methane hotspots in a global model-like version of the Hummock–Hollow model that underestimates methane emissions. We tested the robustness of the parameterization by simulating methane emissions for the …

Go to article

Impacts Of Man-Made Structures On Avian Community Metrics In 4 State Parks In Northwestern Arkansas, R. D. Keith, B. Grooms, R. E. Urbanek Jan 2016

Impacts Of Man-Made Structures On Avian Community Metrics In 4 State Parks In Northwestern Arkansas, R. D. Keith, B. Grooms, R. E. Urbanek

Journal of the Arkansas Academy of Science

Avian community metrics often differ between areas with no human disturbance and areas with high levels of human disturbance. However, the relationships between avian community metrics and smaller-scale disturbances are not as clear. Our goal was to investigate if avian abundance, richness, evenness, and diversity differed in areas with and without small-scale human developments. We used fixed-radius 50-m avian point counts to compare points which contained a man-made structure (n = 47), such as a picnic area, road, or campsite to those that did not contain a man-made structure (n = 181) at 4 state parks in Arkansas during 18 …

Go to article

Occurrence Of Shoal Chub, Macrhybopsis Hyostoma (Cypriniformes: Cyprinidae) In Unusual Habitat In The Arkansas River System Of Arkansas: Could Direct Tributaries Be Refugia Allowing Persistence Despite Fragmentation Of Instream Habitat?, J. A. Brown, H. W. Robison, C. T. Mcallister Jan 2016

Occurrence Of Shoal Chub, Macrhybopsis Hyostoma (Cypriniformes: Cyprinidae) In Unusual Habitat In The Arkansas River System Of Arkansas: Could Direct Tributaries Be Refugia Allowing Persistence Despite Fragmentation Of Instream Habitat?, J. A. Brown, H. W. Robison, C. T. Mcallister

Journal of the Arkansas Academy of Science

No abstract provided.

Go to article

Water-Quality Effects On Phytoplankton Species And Density And Trophic State Indices At Big Base And Little Base Lakes, Little Rock Air Force Base, Arkansas, June Through August, 2015, L. J. Driver, B. G. Justus Jan 2016

Water-Quality Effects On Phytoplankton Species And Density And Trophic State Indices At Big Base And Little Base Lakes, Little Rock Air Force Base, Arkansas, June Through August, 2015, L. J. Driver, B. G. Justus

Journal of the Arkansas Academy of Science

Big Base and Little Base Lakes are located on Little Rock Air Force Base, Arkansas, and their close proximity to a dense residential population and an active military/aircraft installation make the lakes vulnerable to water-quality degradation. The U.S. Geological Survey (USGS) conducted a study from June through August 2015 to investigate the effects of water quality on phytoplankton species and density and trophic state in Big Base and Little Base Lakes, with particular regard to nutrient concentrations. Nutrient concentrations, trophic-state indices, and the large part of the phytoplankton biovolume composed of cyanobacteria, indicate eutrophic conditions were prevalent for Big Base …

Go to article

Dna Barcoding Of The First Recorded American Burying Beetle, Nicrophorus Americanus, In Clark County, Arkansas, J. Kelly, T. Files, N. Reyna, B. Baley Jan 2016

Dna Barcoding Of The First Recorded American Burying Beetle, Nicrophorus Americanus, In Clark County, Arkansas, J. Kelly, T. Files, N. Reyna, B. Baley

Journal of the Arkansas Academy of Science

The American Burying Beetle (ABB), Nicrophorus americanus, is a red-listed endangered species under the Endangered Species Act (16 U.S.C. 1531 et seq.). We serendipitously recorded 3 individuals of this species during a forensic study in the summer of 2013. These specimens represent the first known records for Clark County, AR and the southeastern-most record in the State since the extirpation of the species from the region in the late 1800’s. Two males and one female were collected, photographed, sexed and measured. One male specimen was deceased upon discovery. The remaining two individuals were released. The U.S. Fish and Wildlife Service …

Go to article

New Distributional Records Of The Ohio Shrimp, Macrobrachium Ohione Smith (Decapoda: Palaemonidae) In Arkansas, H. W. Robison, L. Lewis, C. Cox, G. Spooner, R. Adams, C. T. Mcallister Jan 2016

New Distributional Records Of The Ohio Shrimp, Macrobrachium Ohione Smith (Decapoda: Palaemonidae) In Arkansas, H. W. Robison, L. Lewis, C. Cox, G. Spooner, R. Adams, C. T. Mcallister

Journal of the Arkansas Academy of Science

The Ohio shrimp (Macrobrachium ohione) is a migratory (amphidromous) river shrimp that occurs in some Arkansas rivers. It is known from the Upper Missouri River from its mouth downstream to the Gulf of Mexico, but shrimp abundance has declined, particularly upstream of Louisiana. Ohio Shrimp has also been collected in the lower reach of the Missouri River not far from the confluence of the Mississippi River in St. Louis County. Dams and alterations in channel flow are hypothesized to have impacted upriver migrations of shrimp. Current range, abundance, and life history of Ohio shrimp is relatively unknown in the Mississippi …

Go to article

Population Sampling Of Chelonians In An Urban Lake In Jonesboro, Craighead County, Arkansas, J. D. Konvalina, C. S. Thigpen, S. E. Trauth Jan 2016

Population Sampling Of Chelonians In An Urban Lake In Jonesboro, Craighead County, Arkansas, J. D. Konvalina, C. S. Thigpen, S. E. Trauth

Journal of the Arkansas Academy of Science

We conducted a mark-recapture survey for aquatic turtles in Craighead Forest Lake in Jonesboro (Craighead County, Arkansas). From July 2, 2015 to October 14, 2015, we set six hoop nets, baited with fish parts, at specific shoreline locations around the lake. Traps were set twice a week and checked 12 hours after they were set. Carapace length, carapace width, plastron length, and plastron width were measured for each individual. Each turtle was identified to species and its sex was recorded. We also placed a notch in one or more of its marginal scutes to aid in future identification. Finally, a …

Go to article

Acanthocephala Of Arkansas, Including New Host And Geographic Distribution Records From Fishes, C. T. Mcallister, D. J. Richardson, M. A. Barger, T. J. Fayton, H. W. Robison Jan 2016

Acanthocephala Of Arkansas, Including New Host And Geographic Distribution Records From Fishes, C. T. Mcallister, D. J. Richardson, M. A. Barger, T. J. Fayton, H. W. Robison

Journal of the Arkansas Academy of Science

Little is known about the spiny- or thorny-headed worms (Phylum Acanthocephala) of Arkansas and there are no summaries on the acanthocephalans of the state. Here, we provide a checklist of the 22 acanthocephalans that occur in Arkansas’ vertebrates based on previously published records and new data presented herein. In addition, we document a new state record as well as 13 new host records for some fish acanthocephalans.

Go to article

The Ticks (Arachnida: Acari: Ixodida) Of Arkansas, C. T. Mcallister, L. A. Durden, H. W. Robison Jan 2016

The Ticks (Arachnida: Acari: Ixodida) Of Arkansas, C. T. Mcallister, L. A. Durden, H. W. Robison

Journal of the Arkansas Academy of Science

Although ticks are a nuisance to humans and other animals, they are an important part of the biota of North America. In addition, they are vectors of many tick-borne disease agents that can negatively affect higher vertebrates. In Arkansas, there have been no recent comprehensive summaries of the ticks (Acari: Ixodida) in the last 40+ yrs. Here, we provide a summary of the ticks of the state and note the disease agents they can transmit.

Go to article

Long-Term Monitoring And Recovery Of A Population Of Alligator Snapping Turtles, Macrochelys Temminckii (Testudines: Chelydridae), From A Northeastern Arkansas Stream, S. E. Trauth, D. S. Siegel, M. L. Mccallum, D. H. Jamieson, A. Holt, J. B. Trauth, H. Hicks, J. W. Stanley, J. Elston, J. J. Kelly, J. D. Konvalina Jan 2016

Long-Term Monitoring And Recovery Of A Population Of Alligator Snapping Turtles, Macrochelys Temminckii (Testudines: Chelydridae), From A Northeastern Arkansas Stream, S. E. Trauth, D. S. Siegel, M. L. Mccallum, D. H. Jamieson, A. Holt, J. B. Trauth, H. Hicks, J. W. Stanley, J. Elston, J. J. Kelly, J. D. Konvalina

Journal of the Arkansas Academy of Science

We conducted a mark-recapture study of Alligator Snapping Turtles, Macrochelys temminckii, on Salado Creek (Independence Co., Arkansas) during 10 trapping seasons, which spanned a 20-year period (1995–2015). We trapped a total of 163 Alligator Snapping Turtles during 416 trap nights and recorded a total of 35 recaptures during this study. Both the catch per unit effort (CPUE) and Jolly-Seber approaches demonstrated that this population benefitted from removal of harvest pressure, thus leading to an increase in abundance of Alligator Snapping Turtles in the lower ~5 km of the creek. The CPUE averaged slightly greater than 0.24 (317 trap nights) during …

Go to article

Gastrointestinal Parasites Of The Northern River Otter, Lontra Canadensis (Carnivora: Mustelidae), From Arkansas, C. T. Mcallister, A. Surf, R. Tumlison, C. R. Bursey, T. J. Fayton Jan 2016

Gastrointestinal Parasites Of The Northern River Otter, Lontra Canadensis (Carnivora: Mustelidae), From Arkansas, C. T. Mcallister, A. Surf, R. Tumlison, C. R. Bursey, T. J. Fayton

Journal of the Arkansas Academy of Science

No abstract provided.

Go to article

Spring Migration Ecology Of American Woodcock (Scolopax Minor) In The Central Management Region Of The United States, Cari Elizabeth Sebright Dec 2015

Spring Migration Ecology Of American Woodcock (Scolopax Minor) In The Central Management Region Of The United States, Cari Elizabeth Sebright

Graduate Theses and Dissertations

American woodcock (Scolopax minor) is a migratory game bird in population decline since the start of monitoring in 1968. Researchers are interested in gaining knowledge of spring migration ecology to improve migration habitat and mitigate population decline. I captured six woodcock with mist and hand nets on nocturnal habitat and marked them with VHF (very high frequency) transmitters in northern Arkansas. I documented the distance they traveled between nocturnal and diurnal habitats (n=27), and documented diurnal vegetation characteristics at sites used (n=25). I found that woodcock moved an average of 370 m (SE 25.31 m) with the longest movement being …

Go to article

An Inventory Of Endemic Leaf Litter Arthropods Of Arkansas With Emphasis On Certain Insect Groups And Diplopoda, Derek Alan Hennen Dec 2015

An Inventory Of Endemic Leaf Litter Arthropods Of Arkansas With Emphasis On Certain Insect Groups And Diplopoda, Derek Alan Hennen

Graduate Theses and Dissertations

Endemic arthropods of Arkansas were sampled and their nomenclature and distributions were updated. The Arkansas endemic species list is updated to 121 species, including 16 species of millipedes. A study of the millipedes of Arkansas was undertaken, and resulted in the first checklist and key to all millipede species in the state. 68 species are known from Arkansas, including the genera Cylindroiulus and Polydesmus. The first state records for Ophyiulus pilosus, Cylindroiulus sp., and Ptyoiulus coveanus are reported, and new county records are reported for 16 species. This represents the first key to a state's species since 1980, and the …

Go to article

The Abundance And Distribution Of Mallards In The Lower Mississippi Alluvial Valley Of Arkansas, John Andrew Herbert Dec 2015

The Abundance And Distribution Of Mallards In The Lower Mississippi Alluvial Valley Of Arkansas, John Andrew Herbert

Graduate Theses and Dissertations

The management of wintering waterfowl in North America requires flexibility because of constantly changing landscapes and conditions. Many mallards use the lower Mississippi Alluvial Valley (MAV) for wintering habitat, making this an area of emphasis for improving management strategies. In this study, I used mallard observation data from 2009-2014 aerial surveys collected in the Arkansas portion of the lower MAV to explain the abundance and distribution and of mallards. Using spatial hierarchical models and breaking covariate data to 2x2 km grid cells, I analyzed how covariates relate to the changes of abundance and distributions within and among surveys. Mallard abundance …

Go to article

Hydrology-Biology Response Relationships In The Ozark Highlands, Dustin Thomas Lynch Dec 2015

Hydrology-Biology Response Relationships In The Ozark Highlands, Dustin Thomas Lynch

Graduate Theses and Dissertations

I examined flow-ecology relationships among stream communities in the Ozark Highlands, USA. I sampled fish, crayfish, and benthic macroinvertebrates during two consecutive summers, including a drought year (2012) and a flood year (2013). Biological response variables related to community structure were assessed via two different statistical methods: an Information Theoretic approach relating response variables to a priori selected predictor variables incorporating hydrology, habitat, geomorphology, and water quality, and canonical ordination using forward selection to relate these same response variables to a large assortment of hydrologic metrics. In addition to assessing metrics related to predicted natural flow, flow alteration at gaged …

Go to article

Modeling Micro-Topographic Controls On Boreal Peatland Hydrology And Methane Fluxes, F. Cresto Aleina, Benjamin R. K. Runkle, T. Kleinen, Lars Kutzbach, J. Schneider, V. Brovkin Oct 2015

Modeling Micro-Topographic Controls On Boreal Peatland Hydrology And Methane Fluxes, F. Cresto Aleina, Benjamin R. K. Runkle, T. Kleinen, Lars Kutzbach, J. Schneider, V. Brovkin

Biological and Agricultural Engineering Faculty Publications and Presentations

Small-scale surface heterogeneities can influence land-atmosphere fluxes and therefore carbon, water and energy budgets on a larger scale. This effect is of particular relevance for high-latitude ecosystems, because of the great amount of carbon stored in their soils. We introduce a novel micro-topographic model, the Hummock-Hollow (HH) model, which explicitly represents small-scale surface elevation changes. By computing the water table at the small scale, and by coupling the model with a process-based model for soil methane processes, we are able to model the effects of micro-topography on hydrology and methane emissions in a typical boreal peatland. In order to assess …

Go to article

Population Structure Of Central Stoneroller (Campostoma Anomalum) On The Ozark Plateau In Arkansas And Missouri, Mallory Jane Jeffers Jul 2015

Population Structure Of Central Stoneroller (Campostoma Anomalum) On The Ozark Plateau In Arkansas And Missouri, Mallory Jane Jeffers

Graduate Theses and Dissertations

Stream fishes on the Ozark Plateau have been influenced both by historic events (i.e. vicariance versus dispersal) and ecological forces (i.e. flow regime). To examine the role of these processes, genetic structure of Central Stoneroller (Campostoma anomalum), an ecologically important omnivorous minnow with a broad distribution and elevated abundance, was evaluated across populations in the White River drainage of the Ozark Plateau in Arkansas and Missouri. Fin clips of five to eight individuals were taken at each of 20 sites (N=138 individuals; average=6.9), selected so as to represent two different flow regimes: intermittently flashy (N=10 sites; N=73 individuals; average=7.3/ site) …

Go to article

Monochamus Titillator Oviposition And Intraspecific Competition In Shortleaf Pine Bolts, Ryan Patrick Rastok Jul 2015

Monochamus Titillator Oviposition And Intraspecific Competition In Shortleaf Pine Bolts, Ryan Patrick Rastok

Graduate Theses and Dissertations

Monochamus titillator (Coleoptera: Cerambycidae) feed on trees in the family Pinaceae as adults and larvae. Adults feed on healthy twigs and branches and oviposit on stressed, dead, or dying trees. Prior to oviposition, females construct pits on the bark surface using their mandibles. The number of eggs laid beneath bark, where oviposition pits have been constructed, varies greatly. Developmental time and adult body size also vary greatly. I investigated oviposition and intraspecific competition with the goal of determining the degree to which various insect densities and oviposition times impact the following: 1) oviposition pit construction; 2) egg deposition; 3) emergence, …

Go to article

Alliaria Petiolata (M.Bieb.) Cavara & Grande [Brassicaceae], An Invasive Herb In The Southern Ozark Plateaus: A Comparison Of Species Composition And Richness, Soil Properties, And Earthworm Composition And Biomass In Invaded Versus Non-Invaded Sites, Jennifer D. Ogle Jul 2015

Alliaria Petiolata (M.Bieb.) Cavara & Grande [Brassicaceae], An Invasive Herb In The Southern Ozark Plateaus: A Comparison Of Species Composition And Richness, Soil Properties, And Earthworm Composition And Biomass In Invaded Versus Non-Invaded Sites, Jennifer D. Ogle

Graduate Theses and Dissertations

Invasive species are widely recognized as organisms that severely alter ecosystem processes in the habitats to which they are introduced. Alliaria petiolata is one of the most important invasive plants in forests of the northern United States. This study examined the geographic distribution of the plant in the southern Ozarks, as well as the effect that it may be having on natural processes within forests of the region by comparing plant species richness, plant cover, and soil properties in invaded and non-invaded plots. It was found that A. petiolata is not significantly altering species richness, cover, or soil properties in …

Go to article

The Functional And Distributional Ecology Of Mycetozoans Under Changing Edaphic And Climatic Dynamics, Geoffrey Lloyd Zahn Jul 2015

The Functional And Distributional Ecology Of Mycetozoans Under Changing Edaphic And Climatic Dynamics, Geoffrey Lloyd Zahn

Graduate Theses and Dissertations

Investigations into the distribution and ecosystem functions of fruiting amoebae revealed that local-scale environmental conditions can largely explain broad biogeographical patterns in species assemblage, the way in which amoeboid predators shape bacterial communities and how this top-down influence may affect global biogeochemical processes in a changing climate. The distribution and assemblage of protosteloid amoebae on the islands of New Zealand and Hawaii did not yield any expected patterns of island biogeography, and conformed to other global regions studied. The strongest predictor of species richness in a given region was sampling effort and these species do not appear to have any …

Go to article

Management Of A Primordial Problem: Redox-Sensitive Transcriptional Regulation In Methanosarcina Acetivorans, Ryan Christopher Sheehan May 2015

Management Of A Primordial Problem: Redox-Sensitive Transcriptional Regulation In Methanosarcina Acetivorans, Ryan Christopher Sheehan

Graduate Theses and Dissertations

The primordial Earth which hosted the first forms of life was an environment free of oxygen. Early organisms utilized metabolisms dependent upon anaerobic conditions and incorporated systems to which oxygen is deleterious. As the content of oxygen in Earth's atmosphere increased, anaerobic organisms had to acquire methods to sense and combat oxygen and reactive oxygen species. Several mechanisms were advantageous to such anaerobic organisms which correlated transcriptional processes with the redox state of the cell so that energy may be conserved and oxygen stress recovery genes activated during periods of oxidative stress. Iron sulfur (Fe-S) cluster cofactors incorporated within RNA …

Go to article

The Reproductive Ecology Of The Timber Rattlesnake, Crotalus Horridus, In Northwestern Arkansas: Interactions Between Environment, Steroid Hormones, And Life History, Craig Michael Lind May 2015

The Reproductive Ecology Of The Timber Rattlesnake, Crotalus Horridus, In Northwestern Arkansas: Interactions Between Environment, Steroid Hormones, And Life History, Craig Michael Lind

Graduate Theses and Dissertations

In this dissertation I examined the relationship between individual energetic status, hormone production, and life history trait expression in field-active Timber Rattlesnakes, Crotalus horridus. In chapter one I reviewed what is known regarding these relationships in snakes and defined major research goals. In chapter two I described the seasonal profile of testosterone (T) and corticosterone (CORT) in relation to the breeding season and to individual energetic status in males. Results showed that the seasonal pattern of T production in C. horridus was different than other pit viper species with similar mating patterns. Testosterone was elevated in the months leading up …

Go to article

Effects Of Landscape Disturbances On Autotrophic Processes Within Arkansas Ozark Streams, Bradley J. Austin May 2015

Effects Of Landscape Disturbances On Autotrophic Processes Within Arkansas Ozark Streams, Bradley J. Austin

Graduate Theses and Dissertations

Land-use change is one of the most widespread human impacts and can influence abiotic and biotic processes within surrounding streams. For example, streams in agricultural and urban watersheds receive greater light and nutrient inputs that can promote increased algal growth and primary production. Natural gas (NG) infrastructure development, a recent land use change in many regions, may also stimulate forested stream primary production, by reducing forest cover and increasing sediments and nutrient transport. I sampled streams across a NG activity gradient for algal biomass and gross primary production (GPP) to assess potential effects of this emerging land-use type. Algal biomass …

Go to article

First Prev Next Last