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Full-Text Articles in Life Sciences

Demographic Consequences Of Off-River Nesting For Piping Plover (Charadrius Melodus) And Interior Least Tern (Sternula Antillarum Athalassos) In The Lower Platte River System, Nebraska, Elsa M. Forsberg Apr 2024

Demographic Consequences Of Off-River Nesting For Piping Plover (Charadrius Melodus) And Interior Least Tern (Sternula Antillarum Athalassos) In The Lower Platte River System, Nebraska, Elsa M. Forsberg

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

Piping plovers (Charadrius melodus; hereafter, plovers) and interior least terns (Sternula antillarum athalassos; hereafter, terns) are two avian species that nest along the Lower Platte River system (LPRS) in Nebraska. In the LPRS, river sandbars provide natural nesting habitat, but off-river sites provide substantial nesting habitat especially when sandbar habitat is scarce. Although presumed to be important for the persistence of plovers and terns, off-river habitat is not self-sustaining and predicted to decline. Understanding the vital rates of plovers and terns in the LPRS will inform the role of off- river sites in the future conservation …


Connecting The Nebraska Water Quality Index To The Aquatic Microbial Community Of The North Platte River Basin, Nebraska, Paula R. Guastello Nov 2023

Connecting The Nebraska Water Quality Index To The Aquatic Microbial Community Of The North Platte River Basin, Nebraska, Paula R. Guastello

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

The Nebraska Water Quality Index, under development by the Nebraska Department of Environment and Energy, summarizes in a single value eight environmental parameters that have been monitored in Nebraska for nearly 20 years. Water quality parameters including those used in the Nebraska Water Quality Index have been shown in previous studies to impact bacterial growth. As such, this index has the potential to correlate with the freshwater microbial community. Here, I relate the Nebraska Water Quality Index to microbial community composition and structure using 16S rRNA gene amplicon sequence data collected from the North Platte River Basin, Nebraska. This index …


Pronghorn Survival And Resource Selection In Western Nebraska's Agriculturally Dominated Landscape, Katie Piecora Jul 2023

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 …


Soil Microbial Community Dynamics In Response To Prescribed Extreme Fires Following Juniperus Virginiana Invasion In The Loess Canyons Of Nebraska, Julie A. Fowler Dec 2021

Soil Microbial Community Dynamics In Response To Prescribed Extreme Fires Following Juniperus Virginiana Invasion In The Loess Canyons Of Nebraska, Julie A. Fowler

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

In Nebraska and other regions of the Great Plains, the conifer Juniperus virginiana (eastern redcedar) is converting grasslands to dense woodlands. This is driven by the interacting drivers of fire suppression, altered grazing regimes, climate change and other anthropogenic factors, impacting the provisioning of ecosystem services. This vegetation state transition modifies water resource regulation and biogeochemical cycles leading to altered edaphic properties including soil microbial community composition. To restore these grasslands and control J. virginiana spread, prescribed extreme burns are implemented as a management tool through local prescribed burn associations. We hypothesized that the alternative state transition to dense J. …


The Biological Significance And Utility Of Feeding By Dermestes Maculatus, Braymond Adams Dec 2018

The Biological Significance And Utility Of Feeding By Dermestes Maculatus, Braymond Adams

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

With their efficient feeding habits and tolerance to very low moisture and humidity, beetles in the Family Dermestidae are especially adapted to variable environments and habitats. Dermestid cultures have been in use since 1922 in cleaning tissue and flesh from bones, and proven benefit in multiple fields, including zoology, ornithology, and forensics. Dermestid feeding behaviors when coupled with known life stage and insect succession information aids in providing significant entomological evidence. However, the feeding activities of insects, like those of vertebrate scavengers and predators, change remains and may leave artifacts that can be sometimes be difficult to assign to a …


Examining Patterns In Nest Predation Using Artificial Nests, Victoria L. Simonsen Nov 2018

Examining Patterns In Nest Predation Using Artificial Nests, Victoria L. Simonsen

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

The use of artificial nests to study the predation of avian nests has faced disregard by ecologists due to inconsistencies found between the survival rates of real and artificial nests across studies and reviews. The negative perception of artificial nests providing an inconsistent assessment of survival has thus fostered the perception that artificial nests are a secondary option to be used to overcome logistical hurdles associated with achieving sufficient sample sizes in systems where study species are rare or elusive, or as merely a preliminary method to study predation across gradients. We argue that the greatest mistake ecologists have made …


Assessment Of The Ponderosa Woodlands In Nebraska's Wildcat Hills: Implications For Juniperus Encroachment And Management, Allie Victoria Schiltmeyer Jul 2018

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. …


Integration Of Hydrogeophysical Datasets For Improved Water Resource Management In Irrigated Systems, Catherine E. Finkenbiner May 2017

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 …


Assessing Responses Of Betula Papyrifera (Paper Birch) To Climate Variability In A Remnant Population Along The Niobrara River In Nebraska Through Dendroecological And Remote Sensing Techniques, Evan Bumann Jan 2017

Assessing Responses Of Betula Papyrifera (Paper Birch) To Climate Variability In A Remnant Population Along The Niobrara River In Nebraska Through Dendroecological And Remote Sensing Techniques, Evan Bumann

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

Remnant populations of the boreal species Betula papyrifera, found along north-facing canyons and river banks of the Niobrara River Valley in north-central Nebraska, represent one of the southernmost distributions of the species in North America. Although, the species has persisted in the Great Plains after the Wisconsin Glaciation due to the local topography and microclimatic conditions, canopy dieback has been reported in recent years, which is believed to be attributed to temperature change. Therefore, the goals of this research are to: 1) use dendroecological techniques, or the study of tree rings to assess the responses B. papyrifera to intra- and …


A Desert In Disguise: The Resilience Of The Nebraska Sandhills, Jeff Hartman Dec 2015

A Desert In Disguise: The Resilience Of The Nebraska Sandhills, Jeff Hartman

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

The Nebraska Sandhills are the largest sand dune system in the Western Hemisphere, and are unique because they remain relatively undisturbed from row crop agriculture. Research in the past two decades demonstrated that the Sandhills are dynamic on millennial timescales, switching between stabilized, vegetated states to non-vegetated, mobilized states. The Sandhills are currently stabilized, but understanding how ecological processes are altered as sand dunes transition from stabilized to mobilized states, provides insight into the thresholds, stability, and resilience of this grassland ecosystem. My research investigated the impacts of vegetation disturbances on ecological processes and the sand dune surface stability. For …


Decomposition And Nutrient Release Of Different Cover Crops In Organic Farm Systems, Jianru Shi Jun 2013

Decomposition And Nutrient Release Of Different Cover Crops In Organic Farm Systems, Jianru Shi

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

Cover crops act as green manure adding organic matter to agricultural-soils. For legume green manures to be an effective nitrogen (N) source for organic farming systems, their N release must be in synchrony with crop N demand. The objectives of this study were 1) determine the decomposition rates of three common cover crops (white clover, (Trifolium repens,L ) red clover (Trifolium pratense L.) and soybean (Glycine max L) in order to determine when most N was released and its synchrony with subsequent corn crop uptake; 2) we focused on the effect of cover crops on soil …


Building Upon Common-Pool Resource Theory To Explore Success In Transitioning Water Management Institutions, Christina M. Hoffman Apr 2013

Building Upon Common-Pool Resource Theory To Explore Success In Transitioning Water Management Institutions, Christina M. Hoffman

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

Nebraska, like many regions around the world, is faced with the challenge of adapting to a new era in water management. Increasing demands for water resources, mounting concerns over threatened and endangered species, and obligations to abide by interstate water allocation agreements have motivated Nebraska to revisit traditional water management approaches. However, although Nebraska’s water management institutions have undergone much change, little research exists on the influence these changes have had on the ability of water institutions to successfully manage water allocations. This research (1) qualitatively explores the perspectives and experiences of stakeholders in the overappropriated region of the Platte …


Interactions Of Zooplankton And Phytoplankton With Cyanobacteria, Rebecca Alexander Dec 2012

Interactions Of Zooplankton And Phytoplankton With Cyanobacteria, Rebecca 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 …


Chlorophyll-Based Approach For Remote Estimation Of Crop Gross Primary Production: From In Situ Measurements To Satellite Imagery, Yi Peng Jun 2012

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 (PARin …


Biogeochemical Behavior Of Dissolved Arsenic And Uranium Concentrations In Public Water Supply Wells, Kevin J. Mcvey May 2009

Biogeochemical Behavior Of Dissolved Arsenic And Uranium Concentrations In Public Water Supply Wells, Kevin J. Mcvey

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

Public water supply (PWS) wells currently contain dissolved uranium concentrations above the federally mandated maximum contaminant level (MCL) of 30 ppb (parts per billion) and dissolved arsenic concentrations above the 10 ppb MCL. Both uranium and arsenic are known to cause various forms of cancer in humans. Variations in total uranium concentrations in PWS wells in Nebraska indicate a relationship to the duration and rate of pumping in specific wells. Although total arsenic concentrations show some variability over time in specific wells, the relationship to pumping is not as clear. Previous studies show that iron and sulfur bacteria present in …


A Report On Black-Tailed Prairie Dogs In Nebraska-- Their Biology, Behavior, Ecology, Management, And Responses To A Visual Barrier Fence, Nancy S. Foster Dec 1990

A Report On Black-Tailed Prairie Dogs In Nebraska-- Their Biology, Behavior, Ecology, Management, And Responses To A Visual Barrier Fence, Nancy S. Foster

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

I examined the effects of a visual barrier fence, which had a see-through visibility of 600/0, on the foraging, vigilance, and aggressive behaviors of adult female black-tailed prairie dogs from June through August 1990 in central Nebraska. I also examined changes in their home ranges and use of an area in response to this fence. Prairie dogs prefer an open view of their surroundings. Therefore, I expected animals near a visual barrier to spend more time in vigilance and aggression, and less time foraging. Adult female prairie dogs exposed to the visual barrier devoted more time to foraging and less …


Habitat Use And Diet Analysis Of Breeding Common Barn-Owls In Western Nebraska, Joseph A. Gubanyi M.S. Apr 1989

Habitat Use And Diet Analysis Of Breeding Common Barn-Owls In Western Nebraska, Joseph A. Gubanyi M.S.

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

I studied barn owl (Tyto alba) breeding biology in western Nebraska 1984-1986. I had greatest success capturing males (56% success) at night using trap doors at nest sites and females (91 % success) using hoop nets at nest sites during the day. Barn owls removed 16 of 23 tail-mounted radios. Eight birds were radio-tracked for 7-14.5 hours. The mean foraging range was 198 ha (32- 299 ha, n = 8) with < 1 % overlap among birds from adjacent nest sites. Field-tested telemetry error was high (mean displacements of radio-locations for 2 birds were 208 and 241 m). I found no relationship between percent cover in foraging habitat and reproductive success. I identified 10,140 prey items from 15 nest sites and found both annual and seasonal variation in barn owl diets. Microtus ochrogaster occurred most frequently (32.7%) and increased in the diet from 17.6 to 27.2 to 43.5% 1984-1986. M. ochrogaster and Perognathus hispidus annual frequencies were …