Life Sciences Commons^™

Effects Of Wind Turbine Noise On Male Greater Prairie-Chicken Vocalizations And Chorus, Cara E. Whalen

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

Wind energy facilities are constructed without full knowledge of their effects on birds, and the noise generated by wind turbines is a particular concern. I investigated the effects of wind turbine noise on male Greater Prairie-Chicken (Tympanuchus cupido pinnatus) vocalizations and chorus near Ainsworth, NE, USA in 2013 and 2014. I studied 14 leks located in the area surrounding a 36-turbine wind energy facility. I used two main approaches in this study. First, I recorded Greater Prairie-Chicken boom, cackle, whine, and whoop vocalizations at each of the study leks and measured the duration, sound pressure level, peak frequency, …

Population Dynamics And Movement Of Channel Catfish In The Red River Of The North, Stephen F. Siddons

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

Channel Catfish are widely distributed across North America and highly valued as a sport fish and for food. While most Channel Catfish fisheries are managed under liberal harvest regulations, the Red River of the North (Red River) in Manitoba, Canada is managed with restrictive harvest regulations to promote a trophy fishery. Two barriers (dams) are present on the main stem of the Red River and may fragment the population to some degree. My objectives were to: 1) analyze population dynamics of the trophy Channel Catfish population on the lower Red River, 2) compare population characteristics of Channel Catfish in selected …

Resilience Thinking And Structured Decision Making In Social-Ecological Systems, Noelle M. Hart

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

Natural resource management may be improved by synthesizing approaches for framing and addressing complex social-ecological issues. This dissertation examines how structured decision making processes, including adaptive management, can incorporate resilience thinking. Structured decision making is a process for establishing a solid understanding of the problem, values, management options, and potential consequences. Adaptive management is a form of structured decision making in which uncertainty is reduced for iterative decisions through designed monitoring and review. Resilience thinking can help conceptualize complex social-ecological systems and draws attention to the risks of managing for narrowly-focused objectives.

This dissertation provides practical advice to managers and …

Assessment Of Disturbance Effects Of An Existing Wind Energy Facility On Greater Prairie-Chicken (Tympanuchus Cupido Pinnatus) Breeding Season Ecology In The Sandhills Of Nebraska, Jocelyn O. Harrison

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

Recent wind energy development in the Great Plains of North America has given rise to concerns of potential impacts on the greater prairie-chicken (Tympanuchus cupido pinnatus). Recent studies in fragmented landscapes have suggested greater prairie-chickens may avoid wind facilities, which may lead to habitat loss and negative impacts on reproduction and survival. But, it is unknown if there is a similar effect in contiguous grass landscapes. Thus, we investigated the effect of a pre-existing, 36-turbine wind energy facility on greater prairie-chicken nesting, brood-rearing, and spatial ecology in the Nebraska Sandhills. We captured and marked 78 female greater prairie-chickens …

Carbon Storage Potential Of Windbreaks On Agricultural Lands Of The Continental United States, William Ballesteros Possu

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

Agricultural production systems face major challenges under climate change scenarios in terms of expected negative impacts on productivity and persistence of the crops. Greenhouse gases from agriculture continue to rise although not as fast as from other fossil fuel-based human activities. Windbreaks perform several ecosystems functions that improve the local and regional capacity of crop systems to increase yields and offer environmental services by minimizing the negative effects of extreme weather events. Windbreaks also represent an important means of mitigating greenhouse gas emissions. This is predominantly accomplished by the windbreak trees storing carbon (C) in their above and belowground woody …

Introducing Green Manures In An Organic Soybean-Winter Wheat-Corn Rotation: Effects On Crop Yields, Soil Nitrate, And Weeds, Katja Koehler-Cole

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

In organic soybean– winter wheat – corn rotations, animal manure is a common choice to maintain high yields, but leguminous crops grown as green manures after wheat harvest and incorporated into the soil before corn planting, can be an alternative when animal manure is not accessible. Forage legumes with high dry matter (DM) production and high biological N fixation have been shown to meet corn N demand. However, in Eastern Nebraska, lack of precipitation can reduce green manure growth and N fixation, leading to an insufficient N supply for corn, but corn growth can also be impacted by green manure …

Bioenergetics And Habitat Suitability Models For The Chinese Mystery Snail (Bellamya Chinensis), Danielle M. Haak

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

Relatively little is known about the invasive Chinese mystery snail (Bellamya chinensis). This research aims to elucidate some of the mystery surrounding this species. First, we place the species in context with other invasive freshwater snails of the USA and Canada, identifying current information gaps, categorizing shared characteristics among families and species, and comparing functional roles and ecological effects of freshwater snails. We conclude that more focus needs to be directed to regulating the aquarium, pet, and food trades if we are serious about preventing future invasions. Next, we develop a bioenergetics model for the species by quantifying …

Shorebird Migratory Stopover Responses To Local And Regional Change: Habitat Decisions In A Vanishing Landscape, Caitlyn Gillespie

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

Understanding the consequences of anthropogenic change for migratory species is challenging because although they have evolved to cope with environmental uncertainty, migrants still rely on predictable relationships within and among habitats to make informed decisions. Calidris shorebirds rely on ephemeral wetlands during northward migration through mid-continental North America, where favorable habitat conditions are annually and regionally unpredictable and increasingly altered by land-use change. During spring 2013 and 2014, we assessed Calidris habitat use in the Rainwater Basin (RWB) and the Prairie Pothole Region (PPR) at both local and landscape scales. Although anthropogenic change has altered the wetland landscape in both …

Ecology And Management Of Superabundant Fish Populations, Nathaniel T. Stewart

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

Fish population biomasses can reach extreme levels; we term these populations superabundant fish populations. Superabundant fish populations may negatively affect aquatic communities and anglers, necessitating the effective management of the superabundant fish populations. However, there are gaps in our understanding of these populations. The gaps in our understanding hamper our ability to predict effects on valuable sportfisheries and to effectively manage superabundant fish populations. The overall goal of my thesis research is to provide further insight into the ecology of superabundant fish populations and to provide information that will aid in their effective management. First, we described a new method …

Plant Diversity Affects Performance Of Invasive Thistles In Restored Nebraska Grasslands, Katilyn J. Price

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

Invasive plant species threaten native grasslands, affecting nutrient cycling, biodiversity, wildlife habitat, and usable land for production. Consequently, preventing establishment of invasive species is critical before removal becomes difficult and expensive. The purpose of this study was to examine the effects of grassland plant diversity on musk thistle (Carduus nutans) and Canada thistle (Cirsium arvense) establishment and determine which environmental factors (light penetration, soil moisture, plant diversity, and soil nitrogen) account for resistance to invasions. In a field experiment at The Nature Conservancy’s Wood River site (Nebraska), the two invasive thistle species were planted into replicated …

Habitat And Site Selection Of Pheasants And Their Hunters During The Hunting Season, Lindsey Messinger

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

Predator-prey interactions are dynamic and complex with implications for predators, prey, and entire ecological communities. Though predation has obvious mortality costs for prey, equally strong non-consumptive impacts of predation have been the focus of recent studies. Not only are prey affected by their predators through both consumption and fear of predation, but predators are driven by selection to respond to prey behavior. Here, we show how habitat decisions made by highly mobile predators and prey are dynamically linked. In our study system, recreational hunters (predators) make decisions about where to hunt based on a variety of resources (potential prey abundance, …

Soil Preferences Of Nicrophorus Beetles And The Effects Of Compaction On Burying Behavior, Kelly A. Willemssens

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

The American burying beetle, Nicrophorus americanus Olivier was declared federally endangered in 1989 and many efforts to prevent this species from going extinct are ongoing. The Nicrophorus beetles bury small carcasses for reproductive purposes. They also reside in the soil during times of daily and seasonal inactivity. To better understand why N. americanus is in decline, the importance of soil texture, moisture, vegetation, gravel, the burial depth, and the effect of compaction on their burying behavior was examined.

All tested species preferred moist soils with N. orbicollis having a significant preference for wet (pN. marginatus had a significant preference for …

Coupling Soil Oxygen And Greenhouse Gas Dynamics, Karla M. Jarecke

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

Dynamic soil hydrology triggers important shifts in soil biogeochemical and physical processes that control greenhouse gas (GHG) emissions. Soil oxygen (O₂), a direct control on biogenic GHG production (e.g. nitrous oxide-N₂O, carbon dioxide-CO₂ and methane-CH₄), may serve as both an important proxy for determining sudden shifts in subsurface biogenic GHG production as well as the physical transport of soil GHG to the atmosphere. Recent technological advancements offer opportunities to link in-situ, near-continuous measurements of soil O₂ concentration to soil biogeochemical processes and soil gas transport. Using high frequency data, this study …

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 …

Genetic And Morphological Variation In Ecuadorian Astroblepid Catfishes, Katherine M. Lawry

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

The Andean ichthyofauna remains a poorly understood component of Neotropical biodiversity, and stands in stark contrast to the lowland ichthyofauna in terms of number of species and range of distribution. The Climate Variability Hypothesis (CVH) predicts rapid turnover of species along elevational gradients in tropical climates, but it remains unclear whether stream fishes follow this pattern. Astroblepid catfishes represent a distinctive assemblage of species that inhabit high elevation streams throughout the Andes from Panama to Bolivia, and constitute the only native fish family present in the Ecuadorian highland region. In this research, population samples of Astroblepids collected throughout Ecuador’s Napo …

Management Of Channel Catfish Ictalurus Punctatus In The Missouri River, Nebraska, Brandon L. Eder

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

The popularity of catfish Ictaluridae nationally as a sport fish is well documented and angling for catfish on the Missouri River in Nebraska (NMR) is especially popular. Catfish monitoring program by the Nebraska Game and Parks Commission (NGPC) began in 1974 and several short-term evaluations of Channel Catfish population dynamics have been performed. However, no long term analyses of population characteristics have been conducted since the early 1990s. The focus of this research was to summarize the status of Channel Catfish populations in the NMR and give recommendations for future management. I summarized population characteristics, modeled length limit regulations, and …

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 …

A Case Study Of Changing Cropping Diversity And Agricultural Risk In The Doulthabad Mandal Of Telangana State In India, Srikanth Kondabolu

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

The Doulthabad^[1] Mandal is a hot semi-arid agro-ecological sub-region (Rao et al. 2006) located in Mahbubnagar District on the North Telangana Plateau in the state of Telangana. Agriculture is the main occupation in this region, which is populated mostly with small and marginal farmers. This study uses the time period from 1971 to 2004 to study the variation in cropping pattern diversity and distribution of rainfall during the monsoons and understand the implications on production risk in agriculture. Quantitative methods were used in determining the changes in rainfall while qualitative methods were used to study cropping system changes. The …

Informing Flood Plain Wetland Restoration Using Amphibian Monitoring, Ashley Vanderham

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

Wetlands are among the most important and complex ecosystems in the world. They contribute to nutrient cycling, the hydrologic cycle, and provide critical habitat for many plants, fish, and wildlife. Channelization of Missouri River resulted in the loss of many floodplain wetlands. Despite ongoing restoration efforts, there are few ecologically-based performance guidelines, and managers need methods to quantify and assess the success of restored riverine wetland systems.

In 2008 a multi-institutional herpetofauna monitoring project, funded by the U.S. Army Corps of Engineers, was initiated in four states (Kansas, Missouri, Iowa, and Nebraska). The main goal of the project is to …

Influence Of Non-Native Trout On Native Non-Game Fish In Nebraska Headwater Streams, Kelly C. Turek

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

Introduced, non-native trout may have detrimental competitive or predatory interactions with native fishes. However, few studies have experimentally examined interactions between introduced trout and native non-game species. Therefore, the objectives of this study were to determine 1) if non-native rainbow trout Oncorhynchus mykiss influence survival, behavior, movement, or distribution of native longnose dace Rhinichthys cataractae under laboratory conditions, 2) if non-native rainbow trout influence survival of native longnose dace under in-situ conditions using in-stream enclosures, and 3) if native fish populations or communities differ in the presence and absence of non-native trout under natural conditions.

Rainbow trout preyed on longnose …

Response Of Large River Fishes To A Prolonged High Water Event In The Missouri River, Nebraska, Nicholas Paul Hogberg

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

Regulation and modification of large rivers to accommodate human uses have been a root cause of freshwater biodiversity declines. The Missouri River is among the most drastically-altered large river systems in North America, with a series of mainstem impoundments in the upper watershed altering flow characteristics downstream, and channelization throughout the lower river homogenizing instream habitat and reducing off-channel habitat. Precipitation events during the winter and spring 2010-2011 caused flooding of the greatest magnitude and duration since reservoir completion. The large magnitude and long duration of this flood made it unlike any flood in recent history and provided a unique …

Accuracy Or Precision: Implications Of Sample Design And Methodology On Abundance Estimation, Lucas K. Kowalewski

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

Estimation of population size by spatially replicated counts (point-count method) has been used for many large-scale animal-monitoring programs, yet its application in aquatic environments has been limited. Multiple site-specific estimates of abundance can be averaged and combined with covariate data to predict total abundance across an area of interest. Covariate data also provide an understanding of the relationship between abundance and habitat use, which is a fundamental interest of many animal-population investigations. Design of sampling scenarios for point-count population-estimate surveys can influence the accuracy and precision of the population estimate. The first objective of this study was to examine how …

Development Modeling Of Lucilia Sericata And Phormia Regina (Diptera: Calliphoridae), Amanda L. Roe

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

The relationship between insect development and temperature has been well established and has a wide range of uses, including using blow flies for postmortem (PMI) interval estimations in death investigations. To use insects in estimating PMI, we must be able to determine the insect age at the time of discovery and backtrack to time of oviposition. Unfortunately, existing development models of forensically important insects are only linear approximations and do not take into account the curvilinear properties experienced at extreme temperatures. A series of experiments were conducted with two species of forensically important blow flies (Lucilia sericata and Phormia …

Fear Effects On Pheasant Reproductive Ecology And A Curriculum To Teach Wildlife Habitat Selection, Jessica Laskowski

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

Predation risk is an important source of selection that shapes prey density, distribution and abundance. The immediate impacts of predator consumption on prey populations are widespread and well-studied, and a growing body of research demonstrates immediate impacts of predator-induced fear (independent of prey mortality) on prey behavior, physiology and life-history expression. However, predation risk is often seasonally variable and while it is clear that consumption effects often carry over to influence prey population demography for years after predators have disappeared, the temporal carry-over effects of fear on prey populations remain largely unexplored. We assessed effects of fall hunting activity by …

Predicting Invasion Risk Of Non-Native Plants Using A Modified I-Rank Assessment, Justin B. Williams

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

Biological invasions are a global problem responsible for native species declines worldwide. Understanding the invasion risk from non-native species is important in establishing management goals and making decisions for managing native ecosystems. Useful modeling methods for quantifying or predicting invasion risk should consider research needs, data availability, and operate at an appropriate scale. I evaluated risk assessment methods towards answering a specific research question; which plant species pose the greatest risk of becoming invasive or having the greatest negative impact in Nebraska? I selected the I-Rank assessment method, which consists of 20 questions grouped into four risk categories or Subranks: …

A Population Model For Walleye In Nebraska Irrigation Reservoirs, Robert A. Kill

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

Understanding how and why fish population size changes between years is a central theme in fisheries ecology. Fishery agencies have limited time and financial resources, thus there is a need for a quantitative way to direct the limited time and financial resources so agencies can manage fisheries more efficiently. I developed a tool for fishery managers that synthesizes common population indices and evaluated the relative importance of those indices given varying uncertainty in age-0 walleye Sander vitreus survival. Under most circumstances, I determined that resources are best utilized in reducing age-0 survival uncertainty when understanding walleye population growth. I applied …

Determining Scaphirhynchus Sturgeon Population Demographics And Dynamics: Implications For Range-Wide Management, Recovery, And Conservation, Martin J. Hamel

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

Sturgeons (Acipenseridae) have experienced world-wide declines as a result of anthropogenic effects such as over-harvest, habitat degradation, altered flow regimes, and pollution. Nearly all European and Asian sturgeon species have experienced population declines and have subsequently been classified as either threatened or endangered. North American sturgeons have experienced a similar plight in that all eight native sturgeon species are listed as endangered, threatened, or of special concern. Direct linkages between North American sturgeon declines and anthropogenic effects are difficult to assess due to scale considerations, fluctuating environmental conditions, difficulty in capture, and the interaction of all these effects. To recover, …

Anoxia Tolerance Of Forensically Important Calliphorids, Melissa M. Lein

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

Forensically important blow flies, Diptera: Calliphoridae, are among the first organisms to colonize carrion. After eggs hatch, the larvae of most blow fly species feed in an aggregation or “mass.” While in this mass larvae may experience periods of no oxygen (anoxia), little oxygen (hypoxia), or normal oxygen (normoxia), but the tolerance of blow fly larvae to severe hypoxic conditions is not known. I tested the anoxia tolerance of four species of calliphorids (Calliphora vicina, Cochliomyia macellaria, Lucilia sericata, and Phormia regina), using third stage larvae across five temperatures. Experiments were conducted by exposing larvae to pure nitrogen …

Walleye And White Bass Recruitment In Southwest Nebraska Irrigation Reservoirs, Jason Andrew Deboer

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

Walleye Sander vitreus and white bass Morone chrysops are among the most popular sportfish in the reservoirs of the Great Plains. Despite considerable effort by the Nebraska Game and Parks Commission stocking walleye and managing reservoirs for walleye and white bass, populations of walleye and white bass in southwest Nebraska reservoirs are dynamic, as erratic recruitment has led to “boom and bust” fisheries for these two species. We investigated 1) factors regulating walleye and white bass recruitment during an 18-year period at five reservoirs, and 2) walleye spawning ecology at two reservoirs that differ in their degree of environmental variability. …

Shovelnose Sturgeon Reproductive Ecology In The Lower Platte River, Nebraska, Mathew L. Rugg

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

Biodiversity and abundance of freshwater organisms are experiencing drastic declines. Anthropogenic disturbances have altered the natural flow regimes of large rivers, and have led to declines in species that rely on elements of natural flow. Similarly, shovelnose sturgeon distribution has diminished in the last 100 years due to habitat alteration, overharvest, and water contamination. To fully understand the status and viability of a fish population, basic knowledge of a fish’s reproductive strategy is needed. Aspects of reproduction that should be understood to manage for sustainability include maturation, fecundity, and spawning dynamics. There is currently little published information on age/size of …