Terrestrial and Aquatic Ecology Commons^™

Canopy Effects On Tropical Leaf Litter Arthropods, Theodore Peter Sumnicht

Theses and Dissertations

Changes in canopy structure, which are likely to occur at faster rates due to climate change, affect leaf litter structure and the ecology of litter-dwelling organisms. One such change is the increased abundance of lianas in tropical forest canopies. Here, I quantify effects of these changes on tropical leaf litter arthropod communities by surveying patches of Panamanian forest where lianas have been removed, and experimentally isolating two aspects of the litter environment affected by canopy structure: incident light and litter depth. Increased litter produced by liana cutting resulted in increases in ant species richness and arthropod abundance. Structural complexity was …

Canopy Ants Of Central Arkansas And The Atlantic Forest Of Brazil: Community Patterns, Petrus Fauaze Moreira

Theses and Dissertations

Ants in the forest canopy are of special ecological interest due to their high diversity and ecological importance in this relatively inaccessible system. I explored the ecology of ants of temperate and tropical arboreal settings in Central Arkansas and Brazil respectively. I tested the hypothesis that biotic (e.g., tree identity) and abiotic (e.g., spatial distribution) factors regulate the diversity and composition of ants in the forest canopy, as well as the potential conservation benefits of agroforests in the tropics. In Arkansas, tree identity influenced ant species richness in tree crowns, in Brazil, ant species richness was significantly different between primary …

Recovery Of Sensitive Watersheds In The Northeastern United States From Chronic Acidification: The Role Of Soil Chemistry, Chris E. Johnson

Civil and Environmental Engineering - All Scholarship

No abstract provided.

Population Structure And Connectivity Of An Important Pelagic Forage Fish In The Antarctic Ecosystem, Pleuragramma Antarcticum In Relation To Large Scale Circulation, Jason W. Ferguson

OES Theses and Dissertations

Ocean circulation has been identified as a major process controlling the distribution of biological material in marine systems. Large-scale transport by the Antarctic Circumpolar Current (ACC), the Ross and Weddell Gyres, and the Antarctic Coastal Current can promote spatially complex population structure in the Southern Ocean through advection. Antarctic silverfish (Pleuragramma antarcticum), a pelagic, neutrally buoyant notothenioid fish species, are distributed around the shelf systems of Antarctica and are considered an important species rivaling krill as prey for many birds, seals, whales, and other fish. We asked whether silverfish are distributed in independent, discrete populations along the shelf systems of …

Effects Of Prescribed Fire On Ozark Ant Ecology, Robin Michelle Verble

Theses and Dissertations

Fires are among the most conspicuous disturbances affecting leaf litter communities, and are sources of both direct and indirect insect mortality. Fires historically occurred on the Ozark landscape at high frequencies, and modern forest managers utilize prescribed fire to restore and maintain those ecosystems. I examined fire effects at multiple scales, ranging from post-fire patterns in leaf litter arthropod community structure to responses of individual organisms to heat stress. This dissertation summarizes the history of fire occurrences in Ozark forests of Arkansas. It then unifies the results of four observational and experimental studies designed to assess how Ozark forest ant …

Climate's Role In Polar Bear Past [Letters], Kurt E. Galbreath, Joseph A. Cook, Eric P. Hoberg

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Striking temporal concordance between the new date for divergence of polar bears and persistent freezing of the Arctic Ocean suggests that this may be one of relatively few instances in which a specific paleoclimatological episode can be convincingly linked to a specific evolutionary event, and it provides vivid demonstration of climatic forcing as a determinant of diversification in biological systems.

Seasonal Food Habits Of Burrowing Owls (Athene Cunicularia) In Human-Altered Landscapes, Carie Marie Wingert

Master's Theses

In 2004, I initiated a year-long study to investigate the food habits of burrowing owls (Athene cunicularia). Burrowing owls have been found in a variety of human-altered landscapes; however, little is known about burrowing owl food habits in urban landscapes. Burrowing owl food habits during the non-breeding season are also largely undocumented, despite increasing concern over the survival of overwintering burrowing owls. Differences in prey consumption between reproductive and non-reproductive owls during the breeding season have not yet been examined. I collected pellets over a 12 month period at four study sites affected by different levels of human …

Exploring The Houtman Abrolhos Islands, Western Australia. Department Of Fisheries

Fisheries Occasional Publications

This booklet is designed to assist you in exploring and appreciating the Houtman Abrolhos Islands. It provides a general overview on the attributes of the Abrolhos that make it so unique. A place rich in ecological, historical, economic and cultural significance for Western Australia.

Apart from being an introduction to the Abrolhos, the booklet also provides background and context for the various management plans and strategies developed and implemented to sustainably manage these Islands and their surrounding waters.

The Spatial Games: Investigating The Spatial Distribution Of Anax And Select Prey As A Function Of Predator-Prey Interactions, Shane Elizabeth Johnson, Nene Kumashe Ugbah

Biological Sciences

Our study investigated the spatial distribution and movement behavior of predatory dragonfly larvae (Anax) and of two prey types: mosquito larvae and amphipods. Predator-prey interactions have important consequences for the population dynamics of both predator and prey groups and these interactions can shape community structure. We measured behavior of each prey type in the presence of the Anax predator and the behavior of the predator in the presence of these alternative prey types. Observations were made in five-gallon aquaria where a grid pattern allowed us to track the number of moves made by individuals. We compiled data from …

Chlorophyll-Based Approach For Remote Estimation Of Crop Gross Primary Production: From In Situ Measurements To Satellite Imagery, Yi Peng

School of Natural Resources: Dissertations, Theses, and Student Research

The synoptic and accurate quantification of crop gross primary production (GPP) is essential for studying carbon budgets in croplands and monitoring crop status. The objective of this dissertation is to develop a quantitative technique to estimate crop GPP using remotely sensed data collected from close range to satellite altitudes. In this study, a model based on a recently developed paradigm, which relates crop GPP to a product of total crop chlorophyll content and incident radiation affecting vegetation photosynthesis, was justified for the remote estimation of GPP in crops. The model was tested with ground-observed incoming photosynthetically active radiation (PAR_{in …}

The Dynamics Of Location: Influence Of Predation By Chaoborus Larvae On Rotifer Diel Vertical Migration Patterns, Kristina P. Riemer

Lawrence University Honors Projects

The locations of freshwater organisms in lakes are determined by the convergence of many competing factors. While predation pressure is one of these, also important are areas of food concentration and the physical and chemical constraints of a system. Diel vertical migration is a behavior exhibited by freshwater organisms in many taxa that is the result of balancing these factors. Diel vertical migration consists of movement by these organisms throughout the water column in accordance with a 24 hour cycle. This oscillation is generally driven by the competing factors of predation pressure and food acquisition, and is modified by physical …

Macrophyte Communities Of Lake Winnebago: Baseline Study Of Species Composition With Abundances And Water Quality Conditions, Mackenzie Kessenich

Lawrence University Honors Projects

Historical records from Lake Winnebago show minimal macrophyte growth; however, reports from recent years claim that macrophyte growth in some areas of the lake has reached nuisance levels. This study aimed to investigate the species of macrophytes present and their abundances in four near-shore locations, as well as measurements of multiple water quality conditions. Rake sampling was used to identify species and quantify their abundances and distributions. In addition, data were collected on light penetration, Secchi depths, and suspended algae chlorophyll concentrations at each site. These data from shallow near-shore sites reveal trends in changing water clarity and light penetration …

An Approach For Use Of Dual Frequency Identification Sonar (Didson) To Quantify Behavioral Aspects Of Piscivory At Ecologically Relevant Time And Space Scales, Victoria E. Price

Master's Theses

Predator-prey interactions of large vagile fishes are difficult to study in the ocean due to limitations in the space and time requirements for observations. Small-scale direct underwater observations by divers (<10m >radius) and large-scale hydroacoustic surveys (10s - 100s km2) are traditional approaches. However, large piscivorous predators identify and attack prey at the scale of meters to tens of meters. Dual- Frequency Identification Sonar, or DIDSON, is a high-resolution acoustic camera operating in the MHz range that provides detailed continuous video-like imaging of objects out to 30 m range. This technology can be used to observe predator-prey interactions at ecologically …

Terrestrial Habitat Requirements Of Nesting Freshwater Turtles, D. A. Steen, J. P. Gibbs, K. A. Buhlman, J. L. Carr, B. W. Compton, J. D. Congdon, J. S. Doody, J. C. Godwin, Kerry L. Holcomb, D. R. Jackson, F. J. Janzen, G. Johnson, M. T. Jones, J. T. Lamer, T. A. Langen, M. V. Plummer, J. W. Rowe, R. A. Saumure, J. K. Tucker, D. S. Wilson

All Faculty Scholarship for the College of the Sciences

Because particular life history traits affect species vulnerability to development pressures, cross-species summaries of life history traits are useful for generating management guidelines. Conservation of aquatic turtles, many members of which are regionally or globally imperiled, requires knowing the extent of upland habitat used for nesting. Therefore, we compiled distances that nests and gravid females had been observed from wetlands. Based on records of > 8000 nests and gravid female records compiled for 31 species in the United States and Canada, the distances that encompass 95% of nests vary dramatically among genera and populations, from just 8 m for Malaclemys to …

Genetic Variation In Potentially Virulent Vibrio Parahaemolyticus From The Northern Gulf Of Mexico, Nicholas Felix Noriea Iii

Dissertations

Vibrio parahaemolyticus (V_p) is a gram-negative bacterium found naturally in marine and estuarine environments. V_p is found in oysters including those which are later consumed by the public. Sub-populations of potentially virulent Vp contain specific virulence factors and are relevant human pathogens capable of causing gastroenteritis, wound infection, and death. The tdh and trh genes, both encoding hemolysins, have been correlated with the majority of clinical V_p isolates but have not been shown to be the definitive virulence factors.

A total of 146 V_p isolates from the northern Gulf of Mexico were collected and probed …

Effects Of Hypoxia And 4-Tert-Octylphenol On Gene Expression Profiles Of The Sheepshead Minnow (Cyprinodon Variegatus), Arthur Alan Karels

Dissertations

Hypoxia occurs in estuaries of northern Gulf of Mexico and world-wide, with increasing frequency/severity via eutrophication and anthropogenic influences. Hypoxia inducible factors (HIFs) form transcriptional complex and bind DNA at hypoxia responsive elements (HREs) in promoter regions of genes needed for systemic and cellular adaptation of fish to low dissolved oxygen (hypoxia, DO <2.0 mg/ml). Hypoxia-induced activation of HIF-αs can lead to a cascade of downstream activation, such as erythropoietin (EPO). Return to normal DO levels (normoxia), prolyl hydroxylases (PHDs) are activated to degrade HIF-αs back to baseline. Fish are affected by environmental estrogen mimics, like 4-tert-octylphenol (4tOP), binding estrogen receptor alpha (ERα) at estrogen responsive elements (EREs) and activating genes vitellogenin (VTG). Previous research showed overlap or crosstalk between these two mechanistic pathways. Hypoxia triggers unknown factors regulating ERE-mediated ERα signaling pathway, and stressor combinations could increase/decrease hypoxic or endocrine pathway. Research examined molecular/physiological effects of hypoxia (acute and chronic, moderate and severe) and 4tOP (~60μg/L)on adult male and/or female sheepshead minnow (Cyprinodon variegatus). Three genes identified, cloned, and sequenced (HIF-1α, HIF-2α, and PHD3), plus previously identified genes EPO and VTG, were examined in liver/testes exposed to hypoxia and/or 4tOP for cellular/physiological changes. Endpoints examined included mRNA expression from real-time PCR of HIF-1α, HIF-2α, PHD3, EPO, and VTG using cDNA from total RNA extracts, and microarray analyses of genes expressed during the transition from hypoxia back to normoxia. Phylogenetic analyses confirmed isolation of two HIF-α isofoms (HIF-1α and HIF-2α) and the PHD3 isoform. Significant up-regulation of PHD3 occurred within 10 hrs of chronic hypoxia, and persisted when severe (1.5 mg/L) and declined when moderate (~2.5mg/L). Significant up-regulation of HIF-1α and EPO occurred within 30 minutes to 2 hours of onset of acute severe and very severe (~1.08mg/L) hypoxia. Hypoxia acted similar to an estrogen mimic, with huge up-regulation of VTG gene expression in males, and increased VTG levels (additive effect) when hypoxia was combined with 4tOP. Microarray analyses showed 125 genes with significant transcriptional change, with up- or down-regulation from transitions of: (1) hypoxia (72 hrs) to normoxia (74 hrs) and (2) hypoxia+4tOP (72 hrs) to normoxia+4tOP (74 hrs).

Comparison Of Creel Survey Data To Traditional Sampling Techniques In Pit-Lake Fisheries Of Muhlenberg County, Kentucky, Derek L. Rupert

Masters Theses & Specialist Projects

Populations of largemouth bass, Micropterus salmoides, and bluegill, Lepomis macrochirus, were evaluated from five pit-lakes in Muhlenberg County, Kentucky, to determine if accurate proportional stock density (PSD) data can be obtained from a mandatory creel survey. It was hypothesized that the proportion of stock-to-quality (300-400mm) and quality (+400mm) largemouth bass from four years (2007-2010) of creel survey data would be statistically similar to those generated through on-site sampling in 2011. Fish were collected via a combination of gill netting, seining, hook-and-line fishing, and boat-mounted electro-fishing. In two of the pit-lakes, the sampling-generated length frequency data was not significantly …

The Herring River Estuary: Understanding Salt Marsh Restoration And How To Predict The Response Of Phragmites Australis To Increased Tidal Flow, Theresa Murphy

Senior Honors Projects

My presentation invites you to learn about what is involved in planning a salt marsh restoration project. The Herring River Estuary is a disturbed salt marsh ecosystem at Cape Cod National Seashore which has been diked since 1909. The National Park Service (NPS), in cooperation with many partners, is engaged in efforts to restore the now impacted 1,100 acre estuary by re-introducing tidal flow. There is significant complexity involved in trying to restore such an intricate system- from the multitude of environmental factors to important social and economic consequences. There are also several benefits to restored tidal flow. My thesis …

Increase In Ponderosa Pine Density In The Nebraska Sandhills: Impacts On Grassland Plant Diversity And Productivity, Alexa Armstrong

Department of Environmental Studies: Undergraduate Student Theses

Increase in woody species encroachment into semi-arid grasslands and savannas has been of great concern at a global level. Temperature and precipitation are key factors determining vegetation cover; however other factors, such as fire regime and grazing may be at play in semi-arid ecosystems. Historically, in Nebraska’s semi-arid grasslands, woody species have been controlled by periodic fires. Changes in social values and land use, fire suppression, overgrazing, increased N deposition, and climate change, have attributed to the observed shift from grasslands to shrublands or woodlands. The primary objectives of this study were to determine the impacts of Ponderosa pine ( …

Integrating Ecology And Economics For Restoration: Using Ecological Indicators In Valuation Of Ecosystem Services, Eric T. Schultz, Robert Johnston, Kathleen Segerson, Elena Y. Besedin

EEB Articles

Because it can uniquely furnish insights into nonuse values for ecosystem services, survey-based Stated Preference (SP) valuation is widely used to estimate the benefits of ecological restoration. SP surveys ask respondents to select among restoration options yielding different ecological outcomes. This review examines the representation of ecological outcomes in SP studies seeking to quantify values for restoration of aquatic ecosystems. To promote the validity of ecological indicators used in SP valuation, we identified four standards: indicators should be measurable, interpretable, applicable, and comprehensive. We reviewed recent SP studies estimating the value of aquatic ecosystem services to assess whether ecological indicators …