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Articles 301 - 330 of 342

Full-Text Articles in Ecology and Evolutionary Biology

An Agent-Based Model Of Ant Colony Energy And Population Dynamics: Effects Of Temperature And Food Fluctuation, Guo Xiaohui Aug 2014

An Agent-Based Model Of Ant Colony Energy And Population Dynamics: Effects Of Temperature And Food Fluctuation, Guo Xiaohui

Electronic Theses and Dissertations

The ant colony, known as a self-organized system, can adapt to the environment by a series of negative and positive feedbacks. There is still a lack of mechanistic understanding of how the factors, such as temperature and food, coordinate the labor of ants. According to the Metabolic Theory of Ecology (MTE), the metabolic rate could control ecological process at all levels. To analyze self-organized process of ant colony, we constructed an agent-based model to simulate the energy and population dynamics of ant colony. After parameterizing the model, we ran 20 parallel simulations for each experiment and parameter sweeps to find …

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Dissolved Nutrient Ratios And Concentrations Affect Fungal Reproduction And Community Structure Associated With Submerged Leaf Litter And Wood, Jennifer Fitzgerald May 2014

Dissolved Nutrient Ratios And Concentrations Affect Fungal Reproduction And Community Structure Associated With Submerged Leaf Litter And Wood, Jennifer Fitzgerald

Electronic Theses and Dissertations

Litter-associated fungi are important intermediaries in carbon and energy flow in streams. They can obtain nitrogen (N) and phosphorus (P) from both the substrate and the water column. I tested the effects of dissolved nutrients (dissolved inorganic nitrogen (DIN) 40-975 µg/L, soluble reactive phosphorus (SRP) 2-135 µg/L, N:P ratios 2:1, 16:1, 128:1) on fungi associated with leaf litter (maple and rhododendron) and wood in streamside channels at Coweeta Long Term Ecological Research site, North Carolina. This study addressed two main questions: (1) will fungal reproduction (sporulation rate of aquatic hyphomycetes) peak at a dissolved N:P ratio similar to nutrient stoichiometry …

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Paleozoic Seed Bank And Their Ecological Significance, Petra Seka Yehnjong May 2014

Paleozoic Seed Bank And Their Ecological Significance, Petra Seka Yehnjong

Electronic Theses and Dissertations

Soil seed banks are a reservoir of viable seeds present in the soil in plant communities. They have been studied and characterized in various ways in different habitats. However, these studies are limited to modern seed banks. This study extends seed bank studies to the Paleozoic Era. It was hypothesized that size distribution and seed density in Paleozoic seed banks exhibit similar patterns as in modern seed banks. Seed sizes and seed density of fossil seed from Wise Virginia were estimated. Modern seed bank information was obtained from published data. Data were analyzed using one-way ANOVA and Kruskal-Wallis test. The …

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Diel Patterns Of Foraging Aggression And Antipredator Behavior In The Trashline Orb-Weaving Spider, Cyclosa Turbinata, James C. Watts May 2014

Diel Patterns Of Foraging Aggression And Antipredator Behavior In The Trashline Orb-Weaving Spider, Cyclosa Turbinata, James C. Watts

Electronic Theses and Dissertations

Few studies have rigorously assessed the adaptive value of diel rhythms in animals. We laid the groundwork for assessing the adaptive rhythm hypothesis by assaying diel rhythms of foraging and antipredator behavior in the orb-weaving spider Cyclosa turbinata. When confronted with a predator stimulus in experimental arenas, C. turbinata exhibited thanatosis behavior more frequently and for longer durations during the day. However, assays of antipredator response within webs revealed more complex diel patterns of avoidance behaviors and no pattern of avoidance behavior duration. Assays of prey capture behavior found that the likelihood of exhibiting prey capture behavior varied significantly …

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Adaptive Strategies For Foraging And Their Implications For Flower Constancy, Or: Do Honey Bees Multitask?, Ashley E. Wagner May 2014

Adaptive Strategies For Foraging And Their Implications For Flower Constancy, Or: Do Honey Bees Multitask?, Ashley E. Wagner

Electronic Theses and Dissertations

Classical experiments on honey bee time-memory showed that foragers trained to collect food at a fixed time of day return the following day with remarkable time-accuracy. Previous field experiments revealed that not all foragers return to a food source on unrewarded test days. Rather, there exist 2 subgroups: “persistent” foragers reconnoiter the source; “reticent” foragers wait in the hive for confirmation of source availability. To examine how these foragers contribute to a colony’s ability to reallocate foragers across sources with rapidly changing availabilities, foragers were trained to collect sucrose during a restricted window for several days and observed over 3 …

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Inter-And Intra-Population Variability Across The Transcriptome Of Lake Baikal’S Endemic Copepod With Ramifications For Adapting To Climate Change, Larry L. Bowman Jr May 2014

Inter-And Intra-Population Variability Across The Transcriptome Of Lake Baikal’S Endemic Copepod With Ramifications For Adapting To Climate Change, Larry L. Bowman Jr

Electronic Theses and Dissertations

The future of Lake Baikal’s biodiversity is uncertain in response to climate change. Unlike its diverse benthos, Lake Baikal’s zooplankton is species poor, with up to 96% of its biomass being composed of a single Calanoid copepod species, Epischura baikalensis. This study characterizes the genetic differentiation and differential gene expression of E. baikalensis. Using partial-transcriptome sequences obtained by 454 Rosche and Illumina sequencing technologies, the genetic differentiation at inferred single nucleotide polymorphism (SNP) sites and differential gene expression in populations sampled from various parts of the lake were analyzed. The functional genomics of genes showed significant differential …

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Non-Anguimorph Lizards Of The Late Oligocene And Early Miocene Of Florida And Implications For The Reorganization Of The North American Herpetofauna, Kevin Chovanec May 2014

Non-Anguimorph Lizards Of The Late Oligocene And Early Miocene Of Florida And Implications For The Reorganization Of The North American Herpetofauna, Kevin Chovanec

Electronic Theses and Dissertations

Paleokarst deposits from the Oligo-Miocene of northern Florida preserve undescribed herpetofaunal remains that fill important temporal and geographic gaps in our understanding of Cenozoic lizard evolution. Here I describe and discuss the non-anguimorph lizard diversity of the Brooksville 2 (Ar2) and Miller (He1) local faunas to test for patterns of regional and latitudinal provincialism in the contemporary North American record. Collectively, the sites are significant for documenting 1) extralimital occurrences of the tropical clades Anolis and Corytophaninae, 2) a substantial temporal range extension of the modern southeastern endemic Rhineuridae, 3) the earliest record of eublepharid gekkotans from North America, and …

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Investigating The Photosynthesis Of Symbiodinium In Caribbean Gorgonian Corals, Blake Ramsby Jan 2014

Investigating The Photosynthesis Of Symbiodinium In Caribbean Gorgonian Corals, Blake Ramsby

Electronic Theses and Dissertations

Symbiodinium photosynthesis fuels the growth of an array of marine invertebrates, including scleractinian corals and octocorals. Studies examining the symbiosis between Caribbean octocorals and Symbiodinium are sparse, even though octocorals blanket the landscape of Caribbean coral reefs. Here, I compared the photosynthetic characteristics of Symbiodinium in four comCaribbean octocoral species (Pseudoplexaura porosa, Pseudoplexaura wagenaari, Eunicea tourneforti, and Pterogorgia anceps) in outdoor aquaria at ambient temperature. The four octocoral species exhibited similar photochemical efficiencies despite significant differences in Symbiodinium density, chlorophyll a per cell, light absorption by chlorophyll a, and rates of photosynthetic oxygen evolution. Differences in photosynthetic performance between octocoral …

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Growth Of Bald Cypress Boles And Knees As Influenced By Precipitation And Inundation At Sardis Lake, Mississippi, Emily M. Stauss Jan 2014

Growth Of Bald Cypress Boles And Knees As Influenced By Precipitation And Inundation At Sardis Lake, Mississippi, Emily M. Stauss

Electronic Theses and Dissertations

The growth of bald cypress (Taxodium distichum) boles and knees in response to inundation and precipitation over small (< 4 m) elevation gradients was examined by measuring interannual growth increments of boles and knees at five sites at Sardis Lake, Mississippi. There was a significant (p=0.019) growth response to precipitation during November to April (the wet season), but there was not a significant growth response to inundation during the growing season (May to October). Because lake level at Sardis is controlled by the Army Corps of Engineers for flood control, the Sardis Lake shoreline area may be a habitat where growth response to precipitation and inundation differs from systems where precipitation and inundation are linked. The growth of knees from bald cypress roots was compared to growth of the boles in order to determine if knees and boles respond to the same environmental factors. It was found that the knees have high positive correlation coefficients when compared to the tree's bole if we assume that knee growth is initiated in response to a major flood event. If we assume knees grow in response to stress that limits bole growth, we would expect but do not find any discernable relationship between the initiation of knee growth and the timing of flood events.

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Depredation Of Diamondback Terrapin (Malaclemys Terrapin) Nests In North Inlet, Sc: Nest Predator Community And The Cues Used By Raccoons To Locate Nests, Samuel Al Buzuleciu Ii Jan 2014

Depredation Of Diamondback Terrapin (Malaclemys Terrapin) Nests In North Inlet, Sc: Nest Predator Community And The Cues Used By Raccoons To Locate Nests, Samuel Al Buzuleciu Ii

Electronic Theses and Dissertations

Predation on diamondback terrapin eggs has been studied in several terrapin populations across their broad geographic range; however, nest predators have not been studied in South Carolina. Objectives of this project were two-fold: first, identify predators of diamondback terrapin eggs in North Inlet, SC; and second, determine the source of olfactory cue(s) used by raccoons to locate terrapin nests. Terrapin nest predators were identified using a combination of camera traps, visual surveys and trackboards. Raccoons were dominant nest predators and depredated 347 of 349 (combined natural and simulated) terrapin nests during the 2013 nesting season. We identified the source of …

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Assessment Of Bryophyte Communities Along The Waccamaw River, Sc, Christine Elizabeth Raczka Jan 2014

Assessment Of Bryophyte Communities Along The Waccamaw River, Sc, Christine Elizabeth Raczka

Electronic Theses and Dissertations

The focus of this study was to determine the bryophyte communities present along the Waccamaw River, South Carolina and determine if there are any environmental constraints affecting bryophyte diversity. Another aspect of this study was to determine if bryophyte communities are bioindicators for dissolved inorganic nutrients in the Waccamaw River. A total of 1050 bryophyte specimens were collected over the course of the study. Twelve genera were identified and consisted of thirteen moss species and one liverwort species. The bryophyte species were collected at seven sites along the Waccamw River in a nested sampling design which assessed the bryophytes growing …

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Cause And Impacts Of The Early Season Collapse Of Lilium Grayi (Gray’S Lily), On Roan Mountain, Tn/Nc, Russell J. Ingram Aug 2013

Cause And Impacts Of The Early Season Collapse Of Lilium Grayi (Gray’S Lily), On Roan Mountain, Tn/Nc, Russell J. Ingram

Electronic Theses and Dissertations

A population of the rare Southern Appalachian endemic species Lilium grayi, (Gray’s lily) Roan Mountain, TN/NC was monitored for 2 years to determine the cause and impact of an early season collapse. High concentrations of the Lilium spp. host-specific fungal phytopathogen, Pseudocercosporella inconspicua (G. Winter) U. Braun were associated with 19/20 symptomatic and 0/30 asymptomatic plants. Strength of the association between pathogen and disease and the replication of disease symptoms in 4/4 healthy hosts showed that P. inconspicua was the causal agent of the disease referred to as lily leaf spot. Disease had a severe impact on the population …

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A Glyptosaurine Lizard From The Eocene (Late Uintan) Of San Diego, California, And Implications For Glyptosaurine Evolution And Biogeography, David Moscato Aug 2013

A Glyptosaurine Lizard From The Eocene (Late Uintan) Of San Diego, California, And Implications For Glyptosaurine Evolution And Biogeography, David Moscato

Electronic Theses and Dissertations

Glyptosaurinae is an extinct subfamily of lizards of the family Anguidae. Glyptosaurine lizards are known exclusively from the Paleogene of North America and Eurasia, reaching their peak of diversity and distribution in the Eocene. In North America these lizards are largely restricted to the intermontane basins along the Rocky Mountain range, with only sparse, indeterminately-identified skeletal elements known from outside of this region. Glyptosaurine lizards are split into two tribes: the monophyletic Glyptosaurini and paraphyletic “Melanosaurini”. Within Glyptosaurini, the most common and widespread genus is Glyptosaurus. In this study I describe a new specimen assignable to G. sylvestris, …

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Host Use And Geographic Variation In Fall Webworms (Hyphantria Cunea), Katrina J. Loewy Jun 2013

Host Use And Geographic Variation In Fall Webworms (Hyphantria Cunea), Katrina J. Loewy

Electronic Theses and Dissertations

Host use in herbivores is determined by a variety of ecological drivers, including bottom-up and top-down selective pressures such as host abundance, host plant quality, and parasitism pressure. If the relative importance and strength of interactions among these selective conditions change over an herbivore’s geographic range, local patterns of host use should change in response, evident in differing diet breadths. The fall webworm (Hyphantria cunea) is a widespread, polyphagous moth with two color morphs, red and black-headed. In the eastern United States, fall webworms feed on dozens of plant species and previous research demonstrated that host plant abundance …

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Ecological Effects And Genetic Diversity Of The Invading Rhizocephalan Parasite Loxothylacus Panopaei In The Flatback Mud Crab Eurypanopeus Depressus, Kathryn A. O'Shaughnessy Jan 2013

Ecological Effects And Genetic Diversity Of The Invading Rhizocephalan Parasite Loxothylacus Panopaei In The Flatback Mud Crab Eurypanopeus Depressus, Kathryn A. O'Shaughnessy

Electronic Theses and Dissertations

The rhizocephalan barnacle Loxothylacus panopaei (Gissler, 1884) is a parasite of xanthid crabs. Infection results in parasitic castration and anecdysis of the host. Loxothylacus panopaei is invasive to the US Atlantic coast. The parasite's range was expanded by introduction of infected crabs to Chesapeake Bay in the mid-1960s, and now extends from Long Island Sound, New York to Cape Canaveral, Florida. Monthly flatback mud crab (Eurypanopeus depressus Smith, 1869) collections over 13 months (January 2012-January 2013) at three South Carolina locations found an overall parasite prevalence of 24.2% (391 of 1,615), and provided the first reports of L. panopaei at …

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Sagebrush Ecosystem Characterization, Monitoring, And Forecasting With Remote Sensing: Quantifying Future Climate And Wildlife Habitat Change, Collin G. Homer Jan 2013

Sagebrush Ecosystem Characterization, Monitoring, And Forecasting With Remote Sensing: Quantifying Future Climate And Wildlife Habitat Change, Collin G. Homer

Electronic Theses and Dissertations

Sagebrush (Artemisia spp.) ecosystems constitute the largest single North American shrub ecosystem and provide vital ecological, hydrological, biological, agricultural, and recreational ecosystem services. Disturbances continue to alter this ecosystem, with climate change possibly representing the greatest future disturbance risk. Improved ways to characterize and monitor gradual change in this ecosystem are vital to its future management. A new remote sensing sagebrush characterization approach was developed in Wyoming which integrates three scales of remote sensing to derive four primary continuous field components (bare ground, herbaceousness, litter, and shrub), and four secondary components (sagebrush, big sagebrush, Wyoming sagebrush, and shrub …

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Effects Of Dissolved Nutrient Ratios And Concentrations On Litter-Associated Microbial Activity In Streamside Channels, Timothy Burns Jan 2013

Effects Of Dissolved Nutrient Ratios And Concentrations On Litter-Associated Microbial Activity In Streamside Channels, Timothy Burns

Electronic Theses and Dissertations

Heterotrophic consumers, such as microorganisms and invertebrates, play a fundamental role in the flow of carbon and energy in streams. The effects of dissolved nutrient concentrations, and especially ratios, on litter—associated microorganisms and decomposition rates of detritus are poorly understood. This study addressed the responses of heterotrophic microbes to a wide range of concentrations and ratios of dissolved inorganic nitrogen (N) and phosphorus (P) in streamside channels simulating headwater streams. Two main questions were: (1) do microbial parameters and litter decomposition rates peak at a dissolved N:P ratio that approaches the nutrient ratio of microbial biomass, and (2) does microbial …

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Impact Of Macroconsumers On Leaf Breakdown And Detritivores In Wet And Dry Wetlands On A Southeastern Us Coastal Plain Floodplain, Bryanna Libby Jan 2013

Impact Of Macroconsumers On Leaf Breakdown And Detritivores In Wet And Dry Wetlands On A Southeastern Us Coastal Plain Floodplain, Bryanna Libby

Electronic Theses and Dissertations

Interactions among macroconsumers (predators and large omnivores) and detritus breakdown are poorly understood on river floodplains. I evaluated the impact of macroconsumers on leaf breakdown, macroinvertebrate abundance and biomass, and fungal biomass on the Great Pee Dee River floodplain using exclosures in 6 wetlands. Sweetgum (Liquidambar styraciflua) leaves were held in mesh bags and in leaf packs. After 301 days, breakdown rates (k) were low in all treatments (k < 0.003 day-1) and did not significantly differ. Fungal biomass also did not significantly differ between treatments nor did overall macroinvertebrate abundance or biomass. Collector-gatherer invertebrates were significantly more abundant in treatments open to macroconsumers in mesh bags (P<0.001). Shredders had significantly higher biomass in packs held in exclosures closed to macroconsumers (P=0.048). Lack of rain limited stream-floodplain connectivity so a second, shorter study was done in one flooded wetland. After 98 days, pre-conditioned leaves in mesh bags open to macroconsumers had significantly higher breakdown rates (k = 0.0078 day-1) than those closed to macroconsumers (k = 0.0058 day-1; P= 0.050). Fungal biomass did not significantly differ between treatments. Total macroinvertebrate abundance (but not biomass) was higher in mesh bags open to macroconsumers (P=0.014). Scrapers and predators were significantly more abundant in mesh bags opens to macroconsumers (P=0.001 and P=0.004, respectively) than those closed to macroconsumers. These results indicated macroconsumers had a larger impact on litter breakdown in wet floodplain wetlands than in dry ones.

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Differences In Habitat At Two Spatial Scales Fail To Predict Differing Occurrences Of Three Species Of Wintering Ammodramus Sparrows In South Carolina Salt Marshes, Kimberly A. Trinkle Jan 2013

Differences In Habitat At Two Spatial Scales Fail To Predict Differing Occurrences Of Three Species Of Wintering Ammodramus Sparrows In South Carolina Salt Marshes, Kimberly A. Trinkle

Electronic Theses and Dissertations

Salt marshes have low levels of vertebrate diversity yet extremely high rates of endemism. Two of these endemic species are the Saltmarsh (Ammodramus caudacutus) and Seaside Sparrow (A. maritima); the closely related Nelson's sparrow (A. nelsoni) winters exclusively on salt marshes. A previous winter study found that individual sparrows of all three species were highly faithful to specific banding sites, and that the relative abundances of the three species differed by site. I hypothesized that the reason sparrow assemblages varied among sites was that the three species' winter habitat requirements were different. All three species winter in salt marshes, but …

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Distribution And Social Structure Of An Estuarine Bottlenose Dolphin (Tursiops Truncatus) Population In Northern South Carolina, Jamie L. Brusa Dec 2012

Distribution And Social Structure Of An Estuarine Bottlenose Dolphin (Tursiops Truncatus) Population In Northern South Carolina, Jamie L. Brusa

Electronic Theses and Dissertations

Information regarding habitat preference of apex predators may pinpoint areas dense in resources such as prey species. Knowledge of how animals use their habitat can enable the classification and targeted management of important habitat features. This study was conducted to determine the distribution and social structure of an inshore population of bottlenose dolphins within the North Inlet-Winyah Bay estuary in northern South Carolina. Photo-identification surveys were conducted along defined transect routes. Home ranges of individual dolphins were calculated using the minimum convex polygon method and the fixed kernel density method using Geographic Information System (GIS) software. Mean group sizes and …

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Assessment Of Land Use And Neotropical Herpetofauna Along Steep Gradients Of Elevation In An Ecuadorian Ramsar Wetland Site #1143, Nicholas K. Henke Dec 2012

Assessment Of Land Use And Neotropical Herpetofauna Along Steep Gradients Of Elevation In An Ecuadorian Ramsar Wetland Site #1143, Nicholas K. Henke

Electronic Theses and Dissertations

Using a comparative ecological approach, over the course of 18 days at the transition from a particularly wet to dry season in 2010, I assessed herpetofaunal assemblages and related abiotic parameters (i.e., photosynthetically active radiation, specific conductance, temperature and coarse woody debris) between contiguous forest and human impacted areas along three paired transects across the steep elevation gradient at Laguna de Cube, Ramsar site # 1143. Visual encounter surveys were used to capture herpetofauna with species being processed (e.g., weight, digit length, photographed) and identified to the lowest taxonomic level possible. After evaluating transect data for pooling (i.e., no significant …

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Fire-Derived Charcoal Along An Ecological Gradient In The Colorado Front Range, Christopher William Licata Mar 2012

Fire-Derived Charcoal Along An Ecological Gradient In The Colorado Front Range, Christopher William Licata

Electronic Theses and Dissertations

Terrestrial ecosystems are shaped by natural disturbances such as wildland fire. In the intermountain western United States, forests, shrub and grasslands adapt to repeated fires. An important long-term legacy of wildland fires is black C (BC) commonly referred to as char or charcoal. Black C is a recalcitrant C form that has been long known to influence soil physical, chemical, and biological processes that they vary across landscapes and over time. The objective of this research is to address two key areas in the emerging field of ecosystem BC research; 1) how much BC as charcoal C is formed per …

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Placing Birds On A Dynamic Evolutionary Map: Using Digital Tools To Update The Evolutionary Metaphor Of The "Tree Of Life", Sonia Stephens Jan 2012

Placing Birds On A Dynamic Evolutionary Map: Using Digital Tools To Update The Evolutionary Metaphor Of The "Tree Of Life", Sonia Stephens

Electronic Theses and Dissertations

This dissertation describes and presents a new type of interactive visualization for communicating about evolutionary biology, the dynamic evolutionary map. This web-based tool utilizes a novel map-based metaphor to visualize evolution, rather than the traditional "tree of life." The dissertation begins with an analysis of the conceptual affordances of the traditional tree of life as the dominant metaphor for evolution. Next, theories from digital media, visualization, and cognitive science research are synthesized to support the assertion that digital media tools can extend the types of visual metaphors we use in science communication in order to overcome conceptual limitations of traditional …

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Effects Of Hydrologic Connection On Physicochemical Conditions And Algal Properties In Backwaters Of The Lower Mississippi River, Orathai Pongruktham Jan 2012

Effects Of Hydrologic Connection On Physicochemical Conditions And Algal Properties In Backwaters Of The Lower Mississippi River, Orathai Pongruktham

Electronic Theses and Dissertations

In the last 50-100 years, the Mississippi River has been extensively engineered for flood control and navigation purposes. These modifications have substantially decreased the frequency of flooding and degree of contact of the river with its historical floodplain. However, in many areas within the current levee system there remain numerous secondary channels and other backwater sites with which the river is hydrologically connected on a seasonal basis. In this study, the relationships of surface hydrologic connection with the main channel of the Lower Mississippi River to limnological properties and development of phytoplankton biomass in three backwater sites having different patterns …

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Spatial Ecology Of The Spotted Salamander Ambystoma Maculatum During The Nonbreeding Season., Dale Patrick Ledford May 2011

Spatial Ecology Of The Spotted Salamander Ambystoma Maculatum During The Nonbreeding Season., Dale Patrick Ledford

Electronic Theses and Dissertations

Spotted Salamanders, Ambystoma maculatum, are a widely distributed pond-breeding amphibian that spends an estimated 95% of its life in woodlands surrounding breeding ponds. Their terrestrial ecology remains poorly understood. Few studies have tracked the movement patterns of Spotted Salamanders, and they have given limited information on fine scale patterns. Studies of distribution around vernal pool environments have brought increased attention to their terrestrial ecology. To this end I tracked a sample of Passive Integrated Transponder (PIT) tagged animals with a Radio Frequency Identification Device (RFID). Quadrat-variance methods and a Poisson distribution were used to analyze spatial distribution patterns over …

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A Study Of Habitat Selection And Fluctuating Asymmetry Of Amybstoma Tigrinum At Henderson Island Wildlife Management Area In Jefferson County Tn., Christopher Scott Ogle May 2011

A Study Of Habitat Selection And Fluctuating Asymmetry Of Amybstoma Tigrinum At Henderson Island Wildlife Management Area In Jefferson County Tn., Christopher Scott Ogle

Electronic Theses and Dissertations

Studies were conducted on a population of tiger salamanders, Ambystoma tigrinum, at Henderson Island Wildlife Management Area in Jefferson County, TN. Tests were conducted to locate the nonbreeding habitat of the salamanders and to detect any difference in fluctuating asymmetry (FA) between larval populations in a large, permanent pond and an ephemeral wetland. Drift fences were installed with pitfall traps at selected locations around each pond to determine nonbreeding habitat use by adults. Most adult salamanders were found using a blackberry (Rubus sp.) dominated old-field, a grassy field, and a shrub-grass mix field, which were all adjacent …

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Invasion Of Hurricane-Disturbed Scrub Communities On Barrier Islands In Mississippi: A Battle Between Native And Non-Native Ecosystem Engineers, Christine Annette Bertz Jan 2011

Invasion Of Hurricane-Disturbed Scrub Communities On Barrier Islands In Mississippi: A Battle Between Native And Non-Native Ecosystem Engineers, Christine Annette Bertz

Electronic Theses and Dissertations

Some communities may resist invasion because they are dominated by ecosystem engineers. If these dominant species are removed by some catastrophic disturbance, they can be replaced by invasive species that will dramatically alter the ecosystem in a way that may prevent its recovery. I tested several hypotheses related to this idea within barrier island scrub communities dominated by Florida rosemary (Ceratiola ericoides Michx.). Hurricanes represent a major source of disturbance to coastal Florida rosemary communities, and individual rosemary shrubs in three populations recently impacted by major hurricanes were not protected from the storm surge at higher elevation. Unlike inland populations …

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Effects Of Tornado Damage, Prescribed Fire, And Salvage Logging On Oak (Quercus Spp.) Saplings In Upland Oak Forests In Northern Mississippi, Jeffery B. Cannon Jan 2011

Effects Of Tornado Damage, Prescribed Fire, And Salvage Logging On Oak (Quercus Spp.) Saplings In Upland Oak Forests In Northern Mississippi, Jeffery B. Cannon

Electronic Theses and Dissertations

After European colonization and extensive logging folloby long periods of fire suppression, oak dominated forests, woodlands, and savannahs are being replaced by an unprecedented forest ecosystem. In Mississippi, these new forest systems are dominated in the mid- and understory by mesophytic species such as red maple (Acer rubrum L.) and sweetgum (Liquidambar styraciflua L.). Partial thinning of trees folloby prescribed fire can regenerate oaks in managed timber stands. A severe tornado occurred on a monitored oak stand in northern Mississippi. Of the damaged plots, some were treated with either prescribed fire or salvage logging or were left alone. I examined …

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Exploring Patterns Of Genetic Diversity Of A Malagasy Ant Species: Anochetus Madagascarensis, Nicole Annette Lewis Jan 2011

Exploring Patterns Of Genetic Diversity Of A Malagasy Ant Species: Anochetus Madagascarensis, Nicole Annette Lewis

Electronic Theses and Dissertations

Madagascar is extremely diverse and imperiled. Close to 90% of all land dwelling species are endemic to Madagascar (plants, reptiles, mammals and amphibians). Understanding patterns of genetic diversity for species can aid in better conservation efforts. In this study, I focus on the endemic Malagasy ant species, Anochetus madagascarensis. By employing a broad geographic sample of this species from throughout its distribution and a multilocus genetic data set, I explored population structure and historical factors that affected these patterns. I tested hypotheses proposed to be responsible for generating population structure, and by extension the process of speciation in Madagascar, including …

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Ectomycorrhizal Fungal Succession In A Native Monterey Pine Forest And Its Potential Influence Upon Forest Population Dynamics, Kristopher Jordan Hennig Jan 2011

Ectomycorrhizal Fungal Succession In A Native Monterey Pine Forest And Its Potential Influence Upon Forest Population Dynamics, Kristopher Jordan Hennig

Electronic Theses and Dissertations

Ectomycorrhizal fungi are plant symbionts influential to the growth and survival of many plant species found within forest ecosystems throughout the globe. The succession of ectomycorrhizal communities during forest maturation has been observed in a number of systems; however, though it is generally assumed that this process is important for forest dynamics, we do not fully understand the causes of succession and whether it strongly influences metrics of plant population dynamics such as population growth rates or size class structure. I studied a secondary successional chronosequence to test the hypothesis that ectomycorrhizal fungal succession occurs within a native Monterey pine …

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