Physical Sciences and Mathematics Commons^™

Trophic Dynamics Of Flathead Catfish In The Missouri River Bordering Nebraska, Dylan R. Turner

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

Understanding the trophic dynamics of large, riverine ecosystems is complex and requires knowledge from several inputs and outputs of the ecosystem. Most riverine ecosystems have been altered in some way whether through damming, channelizing, or diverting water. The Missouri River is not immune to these anthropogenic alterations. The river has dams throughout its middle portion and is channelized from Sioux City, Iowa to its confluence with the Mississippi River. Flathead Catfish pylodictus olivarius are one of the most ecologically harmful introduced species but little research has looked at the influence native populations of Flathead Catfish have on native prey populations …

Fish And Macroinvertebrate Response To Restored Off Channel Habitats On The Lower Platte River, Nebraska, Caleb Uerling

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

Anthropogenic alterations to large rivers ranging from impoundments to levees have caused many rivers to no longer access the floodplain. The ecological integrity of floodplain rivers depends on the interaction between main-channel and floodplain habitats. Fish communities inhabiting floodplain habitats are often dictated by the type of habitat and conditions within that habitat. As restoration projects are undertaken it is imperative that managers understand how fish and macroinvertebrates respond to these events. We collected fish, macroinvertebrates, and habitat parameters on two restored floodplain habitats on the lower Platte River, Nebraska to answer questions about aquatic community response to floodplain restoration …

Problematizing Socio-Scientific Issues: An Approach To Understanding Student Decision-Making Using Construal Level Theory, Ashley M. Peterson

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

Socio-scientific issues (SSIs) are challenges at the intersection of science and everyday life that require use of scientific knowledge, argumentation skills, personal values, and morals to articulate science-informed decisions. While addressing SSIs, the ways in which individuals define a problem will influence the solution or decision reached. The problem definition can differ along many dimensions, including content and construal level. A construal is a mental construction of the past and future, other places and people, and unlikely events. Construal Level Theory (CLT) suggests pro-environmental intentions are associated with abstract situations. I explore the application of CLT to teaching and learning …

Integration Of Hydrogeophysical Datasets For Improved Water Resource Management In Irrigated Systems, Catherine E. Finkenbiner

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

Water scarcity is predicted to be the major limitation to increasing agronomic outputs to meet future food and fiber demands. With the agricultural sector accounting for 80 – 90% of all consumptive water use and an average water use efficiency (WUE) of less than 45%, major advances must be made in irrigation water management. Precision agriculture, specifically variable-rate irrigation (VRI) and variable-speed irrigation (VSI) systems, offers the technologies to address and manage for infield variability and incorporate that into management decisions. The major limitation to implementing this technology often lies in the management of spatial datasets and the development of …

Plant Diversity Influences The Structure And Function Of A Restored Prairie And Its Responses To Added Disturbances, Rebecca Bevans

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

As global warming, human conversion of natural landscapes to agricultural uses, and widespread biodiversity losses continue to alter the ecosystems we depend on, an understanding of the relationship between ecosystem structure, composition, and function is needed to maintain valuable ecosystem states and their associated functions. Research testing the limits of an ecosystem’s ability to maintain essential structure and functioning under disturbance conditions can aid in this goal.

In this study, I measured the relationship between plant diversity, community structure and functional traits, and their responses to added disturbances. I added disturbances representing those either caused or intensified by human activity …

River Otter (Lontra Canadensis) Distribution And Habitat Suitability In Nebraska, Nathan R. Bieber

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

River otters (Lontra Canadensis) were extirpated in Nebraska by the early 1900’s, but in 1986, the Nebraska Game and Parks Commission (NGPC) began reintroduction efforts. Following reintroductions, the otter was listed as a tier-1 at-risk species in Nebraska. With increasing otter populations, NGPC is evaluating a de-listing plan. In order to inform de-listing efforts, I surveyed Nebraska’s rivers documenting otter sign and used modeling techniques to estimate otter distribution and habitat suitability.

Otter sign surveys were conducted on the navigable rivers of Nebraska. Occupancy modeling techniques were used to examine patterns in otter detections. The best model incorporated distance …

Resilience And Heterogeneity Following Fire In The Nebraska Sandhills, Jack R. Arterburn

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

The Nebraska Sandhills grassland is an expansive, semi-arid ecosystem characterized by vegetation-stabilized rolling sand dunes. The Sandhills grassland is managed for livestock production by seeking to minimizing disturbances, such as fire, that increase bare ground. The increase in bare ground following fire has contributed to the fear of fire leading to the emergence of a mobile sand dune state. We tracked vegetation response following a growing season wildfire that occurred during extreme drought conditions. In wildfire and drought conditions are when one would expect resilience to be overcome leading to a lack of vegetation recovery and a transition to a …

Applications Of Time-Lapse Imagery For Monitoring And Illustrating Ecological Dynamics In A Water-Stressed System, Emma Brinley Buckley

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

Understanding and perceiving the natural world is a key part of management, policy, conservation, and inevitably for our future. Increased demand on natural resources has heightened the importance of documenting ecosystem changes, and knowledge-sharing to foster awareness. The advancement of digital technologies has improved the efficiency of passive monitoring, connectivity among systems, and expanded the potential for innovative and communicative approaches. From technological progression, time-lapse imagery has emerged a valuable tool to capture and depict natural systems. I sought to enhance our understanding of a water-stressed system by analyzing imagery, in addition to integrating images with data visualization to illustrate …

Adaptation To Climate Change Via Insurance And Financial Incentives, Eric R. Holley

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

Catastrophic climatic events have accounted for 72% of global insurance claims and totaled ~$1 trillion from 1980 to 2012. Costs are driven by socio-economic developments and an increased frequency and severity of climatic disasters in which climate change may have been a contributing factor. Climate change is projected to become a more prominent driver of these changes in the decades ahead. Government policies to reduce systemic risk have been the predominant approach for multi-level mitigation and adaptation to climate change. The analysis presented here shows how forceful and effective market-based approaches for adaptation and mitigation to climate change already operate …

The Cosmic-Ray Neutron Probe Method For Estimating Field Scale Soil Water Content: Advances And Applications, William A. Avery

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

The need for accurate, real-time, reliable, and multi-scale soil water content (SWC) monitoring is critical for a multitude of scientific disciplines trying to understand and predict the earth’s terrestrial energy, water, and nutrient cycles. One promising technique to help meet this demand is fixed and roving cosmic-ray neutron probes (CRNP). However, the relationship between observed low-energy neutrons and SWC is affected by local soil and vegetation calibration parameters. This effect may be accounted for by a calibrated equation based on local soil type and the amount of standing biomass. However, determining the calibration parameters for this equation is labor and …

Optimizing The Safety Margins Governing A Deterministic Design Process While Considering The Effects Of A Future Test And Redesign On Epistemic Model Uncertainty, Nathaniel B. Price

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

At the initial design stage, engineers often rely on low-fidelity models that have high uncertainty. Model uncertainty is reducible and is classified as epistemic uncertainty; uncertainty due to variability is irreducible and classified as aleatory uncertainty. In a deterministic safety-margin-based design approach, uncertainty is implicitly compensated for by using fixed conservative values in place of aleatory variables and ensuring the design satisfies a safety-margin with respect to design constraints. After an initial design is selected, testing (e.g. physical experiment or high-fidelity simulation) is performed to reduce epistemic uncertainty and ensure the design achieves the targeted levels of safety. Testing is …

Analyzing The Relationship Of Soil Moisture And Biophysical Variables In Wet And Dry Seasons At A Rainfed And Irrigated Field In Eastern Nebraska, Eric Hunt

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

Agriculture production, particularly of maize and soybeans, is a major component of Nebraska’s economy and identity. However, agricultural production in Nebraska faces increasing challenges. One of the challenges is the potential for excessive groundwater depletion due to increased demand for food and fuel from irrigated Nebraska crops and increasing risks of water stress due to climate change. Therefore, it is has become essential for a deeper understanding of the soil-plant-atmosphere continuum to help producers make more informed management decisions. One of the most important variables is soil moisture. Soil moisture is an integral part of the hydrologic cycle and an …

Acute Toxicity Of Β-N-Methylamino-L-Alanine (Bmaa) To Fathead Minnow (Pimephales Promelas) And Zebrafish (Danio Rerio), Jiayi Wang

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

β-N-methylamino-L-alanine (BMAA) is a neurotoxic amino acid produced by most species of cyanobacteria. Exposure to BMAA has been hypothesized as a cause of ALS and possibly Parkinson’s and Alzheimer’s diseases for several decades. Both in vitro and in vivo experiments revealed that exposure to elevated concentrations of BMAA can damage motor neurons and cause motor dysfunctions. However, the exact mechanism of BMAA-induced neurotoxicity has not been well understood.

Based on the available literature and in spite of its water-soluble and non-protein nature, BMAA appears to be able to bioaccumulate in organisms. The ubiquity of cyanobacteria and the potential for bioaccumulation …

Combating Eutrophication: An Ecosystem Scale Analysis Of Aluminum Sulfate (Alum) Effectiveness Among Lakes, With Comparison To Alum And Biomanipulation Dual Treatment, Christa M. Webber

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

Eutrophic conditions in lakes and reservoirs in agricultural regions often drive summer blooms of toxic cyanobacteria. Aluminum sulfate (alum) applications are commonly used to control cyanobacteria blooms and restore water quality in eutrophic lakes. However, studies of alum treatments often lack true replication, comparison to reference lakes, or comparison to other restoration techniques, such as an alum and biomanipulation combined or “dual” treatments. Without these comparisons, the variation of treatment response between replicate lakes and restoration techniques remains uncertain. Therefore, I sought to assess how water quality is affected by multiple restoration techniques among geographically proximate (1.4 km²) …

Decision Support Tools To Address Climate Change: Climate Model - Land Surface Models, Zea Mays L. (Corn) Phenology And Evapotranspiration-Yield Sensitivity Models For Nebraska, Usa., Jane A. Okalebo

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

Nebraska's climate is highly variable and is expected to change in the future with anthropogenic global warming (AGW), resulting in warmer spring and summer temperatures coupled with more erratic rainfall events. This has strong implications for agriculture in the region, yet it is not clear that current modeling and decision-support tools are adequate to address these looming changes and provide planning, mitigation and adaptation strategies. To address climate change and its implications to agriculture in Nebraska, a set of robust decision support tools are very crucial. This study herein are divided into three chapters, with each chapter addressing a specific …

Evaluation Of Evaporative Drivers And Hydrologic Influences Using Energy And Water Budget Techniques At A Shallow Saline Lake In The Western Sandhills Of Nebraska, Usa, Colin Peake

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

The western Sandhills of Nebraska contain many shallow lakes and wetlands that interact strongly with groundwater and the overlying atmosphere. The region is semi-arid, and most of the lakes are saline, supporting a wide range of ecosystems. Water levels and salt concentrations are highly sensitive to variations in precipitation, evaporation, and groundwater fluxes, making the Sandhills an excellent laboratory for examining the effects of climate on the water balance of interdunal lakes. In this study, we investigate the atmospheric controls on evaporation rates, as well as the water balance of Alkali Lake, one of the more saline lakes in the …

Improving Drought Management For Transboundary River Basins In The United States Through Collaborative Environmental Planning, Crystal J. Bergman

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

Increasing demand for water and the uncertainty of climate change have put pressure on the global water supply, presenting one of the greatest challenges of the 21^st Century for human development. Drought is a natural hazard that further compromises water supply and increases competition among water use sectors. These challenges confirm the need for comprehensive water supply and drought planning. Planning for water, however, is often conducted within political boundaries that are not consistent with the water resource’s natural boundaries, which can result in conflict. Collaborative environmental planning is a sub-discipline of planning that can address the occurrence of …

Improving Time Structure Patterns Of Orthogonal Markov Chains And Its Consequences In Hydraulic Simulations, Juan C. Jaimes-Correa

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

Rainfall¹ occurrences understood as rain events are relevant for agricultural practices because temporal distribution of rainfall highly affects yield production. A few stochastic models satisfactorily generate daily rainfall events while preserving temporal and spatial dependence among multiple sites. I evaluated an extension on the traditional Orthogonal Markov chain (TOMC) model in reproducing the temporal structure of rainfall events at multiple sites in Florida (FL), Nebraska (NE) and California (CA). In addition, a simulation of watershed runoff from rainfall events, reproduced by a single- and multi-site weather generator, was conducted. Results shows that (i) a temporal structure extended …

Interactions Of Zoo Plankton And Phytoplankton With Cyanobacteria, Rebecca J. Alexander

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

Cyanobacteria are a major concern in Nebraska reservoirs and are capable of producing toxins that can cause skin irritations and gastrointestinal problems, as well as affect the nervous system. It is important to determine the mechanisms that can cause cyanobacteria blooms due to the effect they can have on human health. The interaction of zooplankton and other phytoplankton groups with cyanobacteria is important because there is a biological component in surface waters that should be taken into consideration along with the physical and chemical parameters that have been noted to promote cyanobacteria. For example, zooplankton have the ability to alter …

Impacts Of Climate Change On The Surface Water Balance Of The Central United States, 1984-2007, Bo Dong

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

The climate system and the hydrologic cycle are strongly connected with each other. Understanding the interactions between these two systems is important, since variations in climate can trigger extensive changes in the hydrologic cycle, with significant impacts on agriculture, ecosystems, and society. Observations over the central U.S. in recent decades show numerous changes in climatic variables. This includes decreases in cloud cover and wind speed, increases in air temperature, and seasonal shifts in precipitation rate and rain/snow fraction. To assess the impacts of these variations in climate on the regional water cycle, a terrestrial ecosystem/land surface hydrologic model (Agro-IBIS) is …

Groundwater Pollution Risk Assessment Under Scenarios Of Climate And Land Use Change In The Northern Great Plains, Ruopu Li

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

Modeling groundwater vulnerability to pollution is critical for implementing programs to protect groundwater quality. Traditionally, groundwater vulnerability was modeled based on current hydrogeology and land use conditions. However, groundwater vulnerability is strongly dependent on factors such as depth-to-water, recharge and land use conditions that may change in response to future changes in climate and/or socio-economic conditions. For example, global warming may lead to northward shifts in cropping patterns and changes in crop mixes (and use of farm chemicals). Meanwhile, growing demands for biofuels are resulting in expanding corn acreage, and may lead to pressures to remove land from the Conservation …

Hydrochemistry Of Wetlands Along The Platte River Near Ashland, Nebraska, Carrie L. Wiese

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

No abstract provided.

Impacts Of Human Physical Disturbance Of Benthic Communities In Tributaries Of The Niobrara National Scenic River, Kimberly D. Laing

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

No abstract provided.

Preferences For Rural Amenities In Lancaster County, K. Koehler-Cole

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

No abstract provided.

The Influence Of Grazing Systems On Grassland Bird Density, Productivity, And Species Richness On Private Rangeland In The Nebraska Sandhills, Silka Lori Finkbeiner Kempema

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

No abstract provided.

Conservation And Beneficial Functions Of Grassland Birds In Agroecosystems, Andrea Victoria Hanson

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

No abstract provided.

Factors Affecting Songbird Nest Survival And Brood Parasitism In The Rainwater Basin Region Of Nebraska, Max Post Van Der Burg

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

No abstract provided.

Efficacy Of Offshore Breakwater Structures In A Eutrophic Midwestern Reservoir, Larry D. Pape

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

No abstract provided.

Mesopredator Movement, Abundance, And Habitat Selection In The Rainwater Basins Of Nebraska, Christina J. Kocer

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

No abstract provided.

Leaf And Wood Utilization In The Middle Missouri River, Kim Rager

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

No abstract provided.