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University of Nebraska - Lincoln

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

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Articles 91 - 98 of 98

Full-Text Articles in Life Sciences

Retention, Movement, And The Biotic Response To Large Woody Debris In The Channelized Missouri River, Michael W. Archer Jan 2010

Retention, Movement, And The Biotic Response To Large Woody Debris In The Channelized Missouri River, Michael W. Archer

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

Large woody debris (LWD) is an important component of a healthy aquatic ecosystem. However, little is known about the dynamics of LWD in a large, channelized river such as the Missouri River. My objectives were to first, assess the abundance of LWD found along the channelized portion of the Missouri River. Second, I documented movement of LWD that entered the river. Lastly, using PRIMER software I analyzed what effect, if any, river segments, bend types, and LWD had on the community composition of the macroinvertebrate and fish that inhabit the river. Abundance of LWD was greater along bends that have …

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Nest And Brood Survival And Habitat Selection Of Ring-Necked Pheasants And Greater Prairie-Chickens In Nebraska, Ty Matthews Dec 2009

Nest And Brood Survival And Habitat Selection Of Ring-Necked Pheasants And Greater Prairie-Chickens In Nebraska, Ty Matthews

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

Ring-Necked Pheasant (Phasianus colchicus) and Greater Prairie-chicken (Tympanuchus cupido pinnatus) populations have declined in the Midwest since the 1960’s. Research has suggested decreased nest and brood survival are the major causes of this decline due to the lack of suitable habitat. Habitat degradation has been attributed to the shift to larger crop fields, lower diversity of crops, and more intensive pesticide and herbicide use. A primary goal of the Conservation Reserve Program (CRP) is to mitigate the loss of wildlife habitat. Early research found that CRP increased the amount of suitable nesting and brood rearing cover …

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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 …

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Analyses Of High Resolution Hyperspectral Imagery For Characterization Of Ponderosa Pine Woodlands, Cullen R. Robbins Aug 2005

Analyses Of High Resolution Hyperspectral Imagery For Characterization Of Ponderosa Pine Woodlands, Cullen R. Robbins

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

The Bessey Unit of the Nebraska National Forest is a planted ponderosa pine forest located in the Nebraska Sand Hills. Planted in the early 20th Century, it provides a unique opportunity to study the effects of ponderosa pine establishment on the surrounding grassland ecosystem and the effects of increasing pine density on the forest ecosystem. It has been hypothesized that there are key levels of canopy cover at which shifts in ecosystem function occur. The goal of this research was to use remotely sensed data to develop a reliable method for estimating canopy cover. More specifically, canopy cover was estimated …

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A Regional Gis-Based Analysis Of Elk Habitat Suitability In Northwestern Nebraska, Justin W. Fischer Aug 2002

A Regional Gis-Based Analysis Of Elk Habitat Suitability In Northwestern Nebraska, Justin W. Fischer

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

The need to accurately assess the use and suitability of elk (Cervus elaphus spp.) habitat at regional scales will continue to increase as human development encroaches into what was once optimum elk habitat. The objectives of this research were to calculate the relative proportions of habitat use by elk in the Pine Ridge region of Northwestern Nebraska from a set of radio-collared elk locations and generate a habitat suitability model. Habitat variables (Iandcover type, aspect, slope, distance to a road, road density, and distance from the ponderosa pine edge) were measured for each elk location (n = 5,787 dating …

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Plant And Breeding Bird Communities Of Black-Tailed Prairie Dog Colonies And Non-Colonized Areas In Southwest Kansas And Southeast Colorado, Stephen L. Winter Jan 1999

Plant And Breeding Bird Communities Of Black-Tailed Prairie Dog Colonies And Non-Colonized Areas In Southwest Kansas And Southeast Colorado, Stephen L. Winter

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

This research was initiated to determine if plant and bird communities on black-tailed prairie dog (Cynomys ludovicianus Ord) colonies in southwest Kansas and southeast Colorado differed from those found on associated non-colonized areas. Vegetation height and density, and the cover and frequency of numerous plant species differed between prairie dog colonies and non-colonized areas that were co-dominated by mid-height grasses and shortgrasses. A comparison of prairie dog colonies with non-colonized areas that were dominated solely by shortgrasses did not reveal a difference in vegetation height and density. The number of species that differed in cover or frequency between prairie dog …

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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 …

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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 …

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