Physical Sciences and Mathematics Commons^™

Pronghorn Survival And Resource Selection In Western Nebraska's Agriculturally Dominated Landscape, Katie Piecora

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

Nebraska’s pronghorn population has been stable over the last decade, yet their presence on the landscape remains a contentious subject amongst private landowners. Conversion of grassland for crop production and increased anthropogenic activity has drastically altered pronghorn behavior throughout their current range, however basic ecology and resource use by pronghorn in Nebraska remains poorly understood. Establishing baseline population metrics and seasonal patterns of resource use for this population at the eastern periphery of the species range is critical to guide management actions. We deployed GPS collars on 110 adult pronghorn to quantify survival, mortality risk, and seasonal resource selection in …

Bat Use Of Afforested And Encroached Patches And Their Role In Extending Bat Habitat Into The Nebraska Sandhills, Jacob L. Wagner

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

The Nebraska Sandhills are currently undergoing a state shift to a redcedar dominated woodland due to anthropologic planting of eastern redcedar (Juniperus virginiana) and woody encroachment from the periphery of the Sandhills. To better understand this novel ecosystem and how bats are utilizing it I collected data at Barta Brothers Ranch with acoustic sensor grids consisting of 24 100m spaced acoustic sensors placed adjacent to planted windbreaks. Supplemental data from the Nebraska North American Bat Monitoring Program was used for data analysis at larger spatial scales. I used linear regressions and kriging interpolation maps to see how bats used windbreaks …

Application Of Screening In Rangeland Monitoring: Quantifying Early-Warning Signals Of State Transitions In Nebraska, Daniel S. Bauloye

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

Woody encroachment, desertification, and exotic annual grass invasion are regime shifts (i.e., state-transitions) with detrimental effects on ecosystem health and services in grasslands of the North American Great Plains. Traditional approaches to rangeland monitoring are capable of detecting regime shifts after they have already occurred (i.e., diagnosing them); however, proactive management requires earlier warning. Regime shift screening is a new approach to rangeland monitoring capable of providing earlier warning of regime shifts. Regime shift screening proposes assessing the presence, persistence, and non-stationarity of regime shift signals; however, no studies have systematically evaluated these characteristics in real-world landscapes. In this thesis, …

Analysis Of Soil Change Across Nebraska, Trinity Baker

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

The world’s population is growing and an increasing populace requires more resources. These requirements place increasing pressure on the environment and the soil. Soils serve many important functions throughout the world. These functions range from offering a media for food production, providing a sink for organic carbon, nutrient cycling, and improving water quality. It is important to focus on the human impact on soils and their change over time.

For my research I examined how soils across Nebraska have changed over a time period of roughly 65 years. I sampled and analyzed 39 pedons from four Major Land Resource Areas …

Multi-Criteria Evaluation Model For Classifying Marginal Cropland In Nebraska Using Historical Crop Yield And Biophysical Characteristics, Andrew Laws

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

Marginal cropland is suboptimal due to historically low and variable productivity and limiting biophysical characteristics. To support future agricultural management and policy decisions in Nebraska, U.S.A, it is important to understand where cropland is marginal for its two most economically important crops: corn (Zea mays) and soybean (Glycine max). As corn and soybean are frequently planted in a crop rotation, it is important to consider if there is a relationship with cropland marginality. Based on the current literature, there exists a need for a flexible yet robust methodology for identifying marginal land at different scales, which …

Spatial Ecology And Resource Selection Of Bighorn Sheep (Ovis Canadensis) Ewes In A Prairie Badlands Population, Erin Wood

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

The basic spatial ecology and habitat relationships of female bighorn sheep in Nebraska are poorly understood. Establishing seasonal patterns of space use and resource selection for this population at the margin of their historical and current range addresses a key knowledge gap and provides important baseline information for ongoing conservation efforts in Nebraska. We deployed GPS radio-collars on 56 adult ewes in western Nebraska to quantify seasonal space use, movements, and resource selection of ewes. To investigate spatial ecology, we quantified movements of ewes and the factors that influence home range size, seasonal use, and spatial stability across seasons. Home …

Spatial And Temporal Patterns Of Bat Activity In A Southeast Nebraska Agricultural Landscape, Christopher Fill

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

Intensive agriculture is associated with biodiversity loss and species decline. Yet wild species, such as bats, may provide critical ecosystem services to agriculture, even in transformed landscapes. In the United States, bats have been estimated to save the agricultural industry billions of dollars per year. However, white-nose syndrome and habitat loss have led to the decline of many bat species in North America, including the federally threatened northern long-eared bat, Myotis septentrionalis.

To better evaluate the effectiveness of these pest-controlling services, and to increase understanding of bat foraging behavior in these extreme landscapes, I deployed 11 grids of 24 detectors, …

Prairie Grouse Population Trends And Their Historical Drivers In The Nebraska Sandhills, Danielle Berger

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

The Nebraska Game and Parks Commission (NGPC) has monitored greater prairie-chickens (Tympanuchus cupido pinnatus) and plains sharp-tailed grouse populations (Tympanuchus phasianellus jamesi), collectively known as prairie grouse, since the 1950s using spring breeding ground counts. My research modeled long-term, species-specific spatial and temporal trends of prairie grouse abundance and potential environmental drivers in the Sandhills of Nebraska using NGPC’s historical monitoring data. Prairie-chicken populations have increased since the 1950s while sharp-tailed grouse populations have remained stable or slightly declined. These population trends arise in the context of a dynamic landscape. I created indices representing raptor predation …

Implementing The North American Bat Monitoring Program In Nebraska: An Assessment Of Nebraska Bats With An Emphasis On Citizen Science, Baxter Seguin

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

Over the past decade bat species in North America have been under immense stress due to anthropogenic activities throughout the continent along with severe declines from foreign invaders. Though many specific anthropogenic related activities such as deforestation, land-use alteration, and hibernacula disturbance/modification were the primary culprits of negative impacts on bat species in the past, they pale in comparison to the threats bats face today. White nose syndrome a disease caused by the fungus Pseudogymnoascus destructans and wind energy development have caused declines and disruptions to the bat populations of North America at an unprecedented rate.

Due to the significant …

Relationships Among Biodiversity Dimensions Of Birds In Nebraska, Nadejda Mirochnitchenko

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

Biological diversity, or biodiversity, is a multi-dimensional concept that can be decomposed to measure information about taxonomic, phylogenetic, and functional variation within communities. Although the dimensions of biodiversity are interrelated, the assumption that measuring one dimension of diversity can inform about patterns in another dimension does not necessarily follow from theory or empirical study. The relationships among biodiversity dimensions is not well understood, nor how differences among dimensions could influence conservation decision making. Using the avian community as a study system, we explored the relationships of breadth metrics from the taxonomic, phylogenetic, and functional dimensions among each other and across …

Assessment Of The Ponderosa Woodlands In Nebraska's Wildcat Hills: Implications For Juniperus Encroachment And Management, Allie Victoria Schiltmeyer

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

Ponderosa pine (Pinus ponderosa) is a dominant tree species across western North America. Its eastern distribution includes three populations in western Nebraska. This study assesses the distribution, structure and age of ponderosa pine woodlands in one of those regions, the Wildcat Hills. The Wildcat Hills have escaped severe wildfires seen in recent decades in other ponderosa pine regions. Nevertheless, the Wildcat Hills woodlands face multiple threats including climate change, wildfire, drought, pine beetles, and invasive species. Key to these threats is the stand structure of pine woodlands, which have increased in density across much of ponderosa pine’s range. …

Mapping The Ecology Of Information: Hierarchical Habitat Selection By Nebraska Pheasant Hunters, Lyndsie Wszola

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

Hunting regulations are assumed to moderate the effects of hunting consistently across a game population. A growing body of evidence suggests that hunter effort varies temporally and spatially, and that variation in effort at multiple spatial scales can affect game populations in unexpected ways. We set out to determine the causes of variation in hunting effort among ring-necked pheasant (Phasianus colchicus) hunters at four spatial scales: among regions within the state of Nebraska, among sites within a given region, among access points at a given site, and among habitat patches within a site. At each scale, pheasant hunters used direct …

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 …

The Use Of Tree Rings To Study The Impacts Of Stream Flow And Climate Variability On Native And Invasive Woody Species Along A Semi-Arid Riparian Ecosystem In The Great Plains, Usa., Kristen M. Skolaut

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

Forested riparian areas of the Northern Great Plains have historically been dominated by the native Populus deltoides L. vegetation type. Changes in climate, stream flow, groundwater, and management practices in the past few decades have promoted the expansion of the upland native woody species Juniperus virginiana L. and the invasion of the non-native Elaeagnus angustifolia L. into these riparian ecosystems. This study aims at using dendrochronology, or the study of tree rings, to assess the impacts of intra- and inter- annual climatic variability and stream flow over the past decades, on the annual tree ring growth, oxygen and carbon isotopic …

Habitat Use And Abundance Patterns Of Sandhill Cranes In The Central Platte River Valley, Nebraska, 2003–2010, Todd Joseph Buckley

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

The Central Platte River Valley (CPRV) in Nebraska is an important spring stopover area for the midcontinent population of sandhill cranes. Alterations to crop rotation and loss habitat in the CPRV pose a risk to the population. Personnel drove designated routes in the CPRV from 2003–2010 to record the presence of cranes in agricultural fields and estimate abundance. I developed and evaluated models to predict habitat use and flock sizes. Alfalfa was predicted to receive the highest use followed by corn, soybeans, winter wheat, grassland, and shrubland. Use of all habitats and flock size increased as field area increased. Flock …

Breeding Fidelity And Landscape Effects On Distribution Of Mallards And Duck Broods In The Nebraska Sandhills, Zachary J. Cunningham

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

I investigated aspects of mallard (Anas platyrhnchos) breeding ecology in the Nebraska Sandhills during 2007-2008. Previous work in this region suggests that nest success is low for a large area of intact grassland such as the Sandhills. My goal was to conduct a local-scale examination of age distribution and return rates of mallards, and a large-scale examination of brood distribution in the Sandhills region as a whole. This information will help explain factors contributing to the low nest success previously observed, determine relationships between landscape composition and spatial distribution of waterfowl in the Sandhills, and predict productivity and …

Spatial Accuracy Of Climate Networks In Nebraska, Andrea J. Coop

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

Climate data has become increasingly scrutinized for its accuracy because of the need for reliable predictions about climate change. The U.S. has taken great strides to keep up with the demand for accurate climate data. Over the last thirty years, vast improvements to instrumentation, data collection, and station siting have created more accurate data records. This study is to explore the accuracy of existing networks. This study analyzes three climate networks used in Nebraska: the U.S. Historical Climatology Network (HCN), the Automated Weather Data Network (AWDN), and the newest network, the U.S. Climate Reference Network (CRN). Each of these networks …

Late Holocene History Of Dune Activity Along The Elkhorn River In Northeastern Nebraska, Rebecca A. Young

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

The Nebraska Sand Hills have been an important study area for dune activation and the nature of prehistoric drought events in the Great Plains. However, little has been done to understand the impact of these droughts to smaller dune fields along the eastern margin of the Great Plains. This study focuses on the Stanton dune field which is found about 145 km east of the Sand Hills along the southern edge of the Elkhorn River valley in northeastern Nebraska. With a wetter and slightly cooler climate regime than that of the Nebraska Sand Hills and most other central Great Plains …

Natural Selection And Age-Related Variation In Morphology Of A Colonial Bird, Mary Bomberger Brown

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

In May 1996, inclement weather led to the deaths of thousands of Cliff Swallows (Petrochelidon pyrrhonota) in Nebraska. Survivors had larger skeletons, shorter wings and tails, and less wing asymmetry than non-survivors. This population was followed for 10 years to study 1) whether natural selection events result in permanent microevolutionary changes, 2) if variation in climate affects the development of morphological traits, and 3) if morphological traits vary systematically with age.

Patterns in morphology exhibited by swallows following the selection event were studied by measuring yearling birds. Wing and middle tail lengths decreased, beak length and width increased, …

Scraping Behavior In Male White-Tailed Deer As A Potential Means Of Transmitting Chronic Wasting Disease, Travis C. Kinsell

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

Chronic wasting disease (CWD) has become a concern for wildlife managers and hunters across the United States. High prevalence of chronic wasting disease (CWD) in older male white-tailed deer (Odocoileus virginianus) suggests that sex-specific social behavior may contribute to the spread of the disease among males. Scraping is a marking behavior performed by male white-tailed deer during the rut in which a pawed depression and associated over-hanging branch are marked with saliva, glandular secretions, urine, and feces. We placed 71 and 35 motion-activated cameras on scrapes in DeSoto National Wildlife Refuge in western Nebraska and eastern Iowa from …

Seasonal Energy And Water Balance Of A Phragmites Australis-Dominated Wetland In The Republican River Basin (Southwestern Nebraska, Usa), Gregory J. Cutrell

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

Climate and vegetation can dramatically alter the water cycle on local to regional scales. A change in the surface energy and water balance, especially in arid regions, can have significant impacts on local water availability and, therefore, water resource management. The purpose of this study is to understand the role of climate and vegetation in the energy and water balance of a riparian wetland in the central Great Plains. The site is located near the Republican River in southwestern Nebraska, where decreases in streamflow have been observed in recent decades. In an effort to reduce consumptive use from evapotranspiration (ET), …

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.

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.

Applications Of Remote Sensing And Gis To The Studies Of Groundwater-Lake Interactions In The Nebraska Sandhills, Evgueni N. Tcherepanov

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

No abstract provided.

Movements And Habitat Use By Shovelnose And Pallid Sturgeon In The Lower Platte River, Nebraska, Benjamin D. Swigle

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

No abstract provided.

Ecology Of Elk In Northwestern Nebraska: Demographics, Effects Of Human Disturbance, And Characteristics Of Calving Habitat, Bruce A. Stillings

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

No abstract provided.

Biology Of Shovelnose Sturgeon, Scaphirhynchus Platorynchus, In The Lower Platte River, Nebraska, Robin L. Hofpar

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

No abstract provided.

Riparian Habitats Of The Central Platte As A Corridor For Dispersal Of Small Mammals In Nebraska, Thomas D. Silvia

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

No abstract provided.

Application And Evaluation Of A Biotic Index To Sand Hills And Streams Of Nebraska, Gregory T. Michl

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

No abstract provided.

Avian Use Of Riparian Corridors And Adjacent Cropland In East-Central Nebraska, Rebecca L. Fitzmaurice

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

No abstract provided.