Life Sciences Commons^™

The Effect Of 6-Methoxybenzoxazolinone On Reproductive Condition In The Hispid Cotton Rat, Sigmodon Hispidus, Vera Lee Adams

Biological Sciences Theses & Dissertations

A non-estrogenic hormone, 6-methoxybenzoxazolinone (6-MBOA), found in young growing grasses, has been shown to be a reproductive initiator in several herbivorous rodents. However, the mechanism by which 6-MBOA initiates reproduction has not been determined. Many believe that 6-MBOA represents a reliable cue that the vegetative growing season has begun, but it is unknown whether this hormone is a primary cueing mechanism or if it works in conjunction with other environmental factors. Therefore, a controlled laboratory experiment was conducted using male and female Sigmodon hispidus, the hispid cotton rat, to determine whether different dosages of 6-MBOA (4μg, 40 …

The Influence Of Temperature Salinity And Postlarval Transport On The Distribution Of Juvenile Spiny Lobsters, Panulirus Argus, In Florida Bay, Jennifer Marie Field

Biological Sciences Theses & Dissertations

Florida Bay is a major nursery for the Caribbean spiny lobster, Panulirus argus. The Bay contains a series of hardbottom or seagrass-covered basins separated by mudbanks, which serve as barriers to water circulation and presumably to transport of postlarvae. Temperatures can fluctuate dramatically in the basins and salinities range from 35 ppt to > 50 ppt. In this study I: i) investigated the physiological tolerance of spiny lobster postlarvae to combinations of temperature and salinity representative of conditions in Florida Bay, and ii) examined how postlarval availability and habitat structure influence spiny lobster recruitment into basins. I measured juvenile lobster …

Phytoplankton Assemblages Associated With A Bloom Of Ptychodiscus Brevis Off The North Carolina Coast, Traycie Lea West

Biological Sciences Theses & Dissertations

A bloom of the dinoflagellate Ptychodiscus brevis occurred off the North Carolina coast in late 1987, and samples were forwarded by NOAA to the Old Dominion University Phytoplankton Laboratory for total phytoplankton analysis. Six sampling stations were chosen to represent different bloom scenarios and these six were clustered into three site groups based on the concentrations of statistically significant taxa. Abundances of phytoplankton taxonomic groups over time were examined in relation to P. brevis concentrations to identify any general tendencies. These results indicated the total phytoplankton concentration, and most taxonomic groups, increased at all three site groups regardless of the …

Age And Growth Of Larval And Juvenile Atlantic Croaker, Micropogonias Undulatus, From The Middle Atlantic Bight And Estuarine Waters Of Virginia, Stephen W. Nixon

Biological Sciences Theses & Dissertations

Sagittal otoliths were used to determine the age and growth of 605 larval and juvenile Atlantic croaker, Micropogonias undulatus, collected in the Middle Atlantic Bight (MAB) and estuarine waters of Virginia. A Laird-Gompertz model (r2 = 0.95) was used to describe the growth of croaker up to 65 mm standard length (SL) and 142 days (t): S1_(t) = 2.657 Exp {4.656 [1-Exp (-0.008lt)]}; SL_(t) = standard length at day t. Generally, croaker collected inshore were larger and older than those collected offshore, indicating estuarine immigration from offshore spawning grounds. Back-calculated hatch-dates indicated spawning over an 8- month period …

The Vegetation Of Great Smoky Mountains National Park: Past, Present, And Future, Mark D. Mackenzie

Doctoral Dissertations

This research investigates the vegetation of Great Smoky Mountains National Park (GRSM) using three different techniques: 1) analysis of vegetation data collected circa 1930, 2) remote sensing of current (1984) vegetation using Landsat Thematic Mapper (TM) satellite imagery, and 3) the integration of gradient analysis with forest succession modeling.

Analysis of the 1930's data revealed that Castanea dentata was the dominant species in the GRSM at that time, even with the introduction of the chestnut blight to the park in 1926. Classification of the 1930's plot data identified 16 unique vegetation types ranging from the low elevation, xeric Pinus rigida …

Influence Of The Ruminant Digestive Process On The Germinability Of Range Forage Species, Mohammed S. Al-Mashikhi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Ingestion and dispersal of seeds of desirable species by domestic livestock is potentially important as a range improvement practice, but the passage of seed by livestock has only been studied in a fragmented way, particularly for species adapted to rangelands of western North America. The objectives of this research were to examine the effects of different periods of exposure to in vitro and in vivo digestion processes in cattle on the germinability of several grass species, and determine if the in vitro incubation technique is a good predictor of seed fate following passage through the ruminant digestive tract.

Seeds of …

Population Dynamics In Response To Fire In Quercus Laevis - Pinus Palustris Barrens And Related Communities In Southeast Virginia, Allen E. Plocher

Biological Sciences Theses & Dissertations

Permanent plots in the Zuni Pine Barrens (Isle of Wight Co., Virginia) were sampled in order to: quantify plant population dynamics in response to fire, compare these dynamics among different moisture regimes, compare the effect of mechanical understory removal to that of fire on tree seedling and herbaceous dynamics, and determine the effect of dense lichen (Cladonia spp.) coverage on pine seedling establishment and survival. Fire resulted in 40% aboveground mortality in the overstory, 80% in the sapling/large shrub layer, and nearly 100% in the understory, followed by a 3.3 to 10.6 fold increase in understory density. Regeneration …

Evaluation Of Long Term Changes In The Macrobenthic Community Of The Southern Branch Of The Elizabeth River, Virginia, William S. Hunley

Biological Sciences Theses & Dissertations

Long-term changes in the macrobenthos of the Southern Branch of the Elizabeth River, Virginia were investigated by comparing the present study of community structure with that described ten years earlier by Hawthorne (1980). The results indicated that dominant organisms remained relatively constant in composition but exhibited considerable fluctuation in density. Differences in diversity and spatial distribution of fauna were also observed relative to the previous decade.

Multivariate statistical analyses indicated the macrobenthos exhibited significant spatial and seasonal patterns. Sediments characterized as silts and clays predominated down river while sandier sediment types were most common farther upriver. The spatial distributions of …

The Effects Of Crayfish Grazing On Benthic Algal Community Dynamics In Southwestern Lake Michigan, Kristi A. Zenchak

Master's Theses

No abstract provided.

Aspects Of The Ecology Of The Wood Turtle, Clemmys Insculpta (Leconte), In West Virginia, Allan J. Niederberger

Theses, Dissertations and Capstones

An ecological study of the wood turtle, Clemmys insculpta (LeConte), was conducted in West Virginia from May 1991 to March 1993. Population structure at the primary study area (WV #1) was estimated to be 46% juvenile (H-8 yrs. old), 26% female and 28% male. Total population estimate for WV #1 was 337 wood turtles, with an aquatic density of 1,980 turtles per Hectare of river and a terrestrial density of 22.5 turtles per ha of terrestrial habitat. Growth measurements and estimates indicate rapid initial growth tapering off at year 8 and gradually declining through year 16. Males grow slightly faster …

Vegetative Habitat Analysis Of Proposed Mine Sites In The Mojave Desert: The First Step Towards Revegetation Of Disturbed Desert Communities, Jim Van Brunt

Theses Digitization Project

No abstract provided.

Human Impacts On Beach Use By Wintering And Migrating Birds In The Lower Chesapeake Bay, Ellen Fitzsimmons Mclean

Dissertations, Theses, and Masters Projects

No abstract provided.

An Investigation Of The Host Specificity Of The Brown-Headed Cowbird, Brian D. Peer

Masters Theses

We attempted to determine the factors associated with the lack of parasitism of the Common Grackle (Quiscalus quiscula) by the Brown-headed Cowbird (Molothrus ater). We investigated the breeding phenology of the two species, the responses of colonial- and noncolonial-nesting grackles to female cowbird models, the frequency of artificial egg rejection by grackles, incubation success of cowbird eggs transferred into grackle nests, and the survival rates of cowbirds cross-fostered into grackle nests.

By the time cowbirds began egg-laying at our study sites, 88.5 % of all grackle nests were beyond the point of successful parasitism. Grackles responded …

Distribution And Occurrence Of Eriogonum Visheri A. Nels. On The Medora And Mckenzie Districts, Little Missouri National Grasslands, In North Dakota, Staria S. Vanderpool

Theses and Dissertations

Eriogonum visheri A. Nels. (Polygonaceae) is a plant species whose distribution in North Dakota is incompletely known. The plant species is listed by North Dakota Heritage Program personnel as a G5/S2S3 [G5 = demonstrably secure globally, although it may be rare; S2 = imperiled in the state (6-20 occurrences) or vulnerable to extirpation; S3 = rare in the state (20+ occurrences)]. The species is Federally listed as C2 [current information indicates that listing as endangered or threatened may be warranted, but information about the species is presently inadequate to support immediate ruling] (Northern region, USDA Forest Service, 1991). The limited …

Life History, Population Dynamics And Yield-Per-Recruit Modeling Of Atlantic Croaker, Micropogonias Undulatus, In The Chesapeake Bay Area, Luiz R. Barbieri

Dissertations, Theses, and Masters Projects

Otoliths, scales, dorsal spines, and pectoral fin rays, of Atlantic croaker, Micropogonias undulatus, were compared for legibility of presumed annuli and precision in repeated readings, to determine the best structure for ageing. Marks on transverse otolith sections were easiest to read and showed the best agreement between readings. Fish collected in Chesapeake Bay and in Virginia and North Carolina coastal waters during 1988-1991 were then aged using otolith sections. Ages 1-8 were recorded, but eight-year-old fish were rare. Marginal increment analysis showed that for ages 1-7 annuli are formed once a year during the period April-May. Otolith age readings were …

Immigration Of Blue Crab (Callinectes Sapidus) Megalopae In The York River, Virginia: Patterns And Processes, Eugene J. Olmi Iii

Dissertations, Theses, and Masters Projects

Following larval development in coastal waters, the postlarval stage, the megalopa, of the blue crab enters estuaries and colonizes juvenile/adult habitats. I examined the dynamics of the immigration of blue crab megalopae in the York River, Virginia. Plankton samples were collected nightly during flood tide in the York River Jul-Nov 1987, 1988 and 1989 to quantify variation in abundance of blue crab megalopae during the recruitment season. The abundance of megalopae was highly episodic, and significantly correlated with wind stress to the west (1987, 1988 and 1989), wind stress to the north (1989), and observed tidal range at Gloucester Point …

The Effects Of Nest-Box Visibility And Proximity On The Frequency Of Brood Parasitism In Wood Ducks, Roger W. Jansen

Masters Theses

I studied the effects of nest box visibility and clustering on the rate of intraspecific brood parasitism (IBP) in Wood Ducks (Aix sponsa) at Lake Shelbyville Fish and Wildlife Area in Moultrie County, IL from 2 March 1992 to 22 June 1992. Sixty-eight percent of the nest boxes sampled were used and 33% of the nests were destroyed by predators. Mean clutch sizes of unparasitized (x = 9.2) and parasitized (x = 15.2) nests were significantly different. The parasitism rate in Wood Duck nests was 54%. More visible boxes had a tendency to be parasitized at a higher rate than …

Growth And Survival Of Larval Fishes: The Role Of Zooplankton Abundance And Competition, Michael T. Welker

Masters Theses

Interactions among larval gizzard shad, bluegill and zooplankton prey were examined via a controlled mesocosm experiment and field sampling in Lake Shelbyville, Illinois. In the mesocosm experiment gizzard shad growth and survival were negatively correlated with shad density and positively correlated with macrozooplankton prey. Bluegill growth was also positively correlated with prey availability, but survival was uniformly high despite differences in zooplankton abundance and fish density. Declines in macrozooplankton and copepod biomass were related to fish density. In Lake Shelbyville limnetic overlap of larval gizzard shad and bluegill was limited to a three week period, with the interval of greatest …

Biotic, Abiotic, And Behavioral Patterns Associated With The Nocturnal Movements Of Shrews, Patrick T. Sullivan

Masters Theses

Thirteen trails left by shrews coated with fluorescent powder were examined for microhabitat documentation. Thirteen data parameters were collected from each trail, two of which differed significantly between Blarina brevicauda and Sorex longirostris. The small soricid Sorex longirostris was captured in areas with higher grass content, and lower wooded content, than the larger Blarina brevicauda. The difference in microhabitat use may be a key mechanism in reducing competition between these two species.

Ecology Of The State Endangered Yellow Mud Turtle, Kinosternon Flavescens In Henry Co., Illinois, Michael W. Tuma

Masters Theses

Illinois populations of the state endangered yellow mud turtle (Kinosternon flavescens) persist in scattered locations on sand prairies. The largest population occurs on a remnant sand prairie of the former Green River Marsh in Henry Co. A study was conducted during 1992 to determine important criteria for preserve design. These criteria included extent of turtle movements within the site and habitat use. Turtles were captured by aquatic hoop traps, drift fence, and by hand from May 11 to August 31. A total of 16 adults, four juveniles, and eight hatchlings were captured. Population size was estimated at 44.80 adults using …

The Relationship Between Lifespan And Reproduction In The Giant Waterbug (Belostoma Flumineum), Wendy Nixdorf

Masters Theses

The evolutionary significance of senescence and death is poorly understood. Life history theory suggests that the allocation of energy to growth or reproduction is necessarily associated with a decrease in energy available for maintenance of the soma. This study attempted to determine if an investment in reproduction would decrease longevity in the giant waterbug (Belostoma flumineum). Male and female waterbugs were collected from the field as last instar stage nymphs and maintained under controlled laboratory conditions. Individuals were randomly assigned to mating effort treatments, (virgins or breeders with breeding efforts ranging from 1 to >5 times). Following breeding, …

The Distribution And Occurrence Of Aerobic Heterotrophic Antimicrobic-Producing Bacteria Isolated From The Lower Chesapeake Bay, Linda Lea Gilmer

Biological Sciences Theses & Dissertations

Three different estuarine microenvironments in the lower Chesapeake Bay were investigated for the occurrence and geographical distribution of antimicrobic-producing bacteria. Samples were taken from the water column, fish skin, and algal surfaces. A total of 1472 bacterial isolates were assayed for antimicrobial activity against fungal, Gram-negative and Gram-positive bacterial test organisms. Of the total bacterial isolates assayed, 5. 2% were active antimicrobic producers. Algal surf aces were shown to have a higher incidence of antimicrobic-producing bacteria than the water column or fish skin. No antimicrobic activity was demonstrated by bacteria isolated from the flounder fish skin. The majority of the …