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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Spatial Ecology and Captive Behavior of Rehabilitated Black Bears in Utah

Myers, Patrick J. 01 May 2016 (has links)
Animal movements and space use are fundamental components of life and play integral roles in organismal fitness, population dynamics, and the ecology and evolution of species. The heterogeneous distribution of resources and the movement required to access them, results in ecology being a fundamentally spatial concept. Thus, elucidating animal-habitat relationships is a central focus of wildlife ecology and conservation. I utilized GPS technology, resource selection functions, and generalized linear mixed models, to investigate the immediate post-release movements, denning chronology, release-site fidelity, and season-delineated movements, home ranges, and resource use for six, orphaned and rehabilitated black bears (Ursus americanus). This study represents the first application of GPS monitoring and resource selection for rehabilitated black bears. Data from this study provide insights into the activity of released rehabilitated black bear cubs, highlight trends among the release cohort, and illustrate the variability of individual behavior. Results indicate species-typical behaviors, with bears denning shortly after their releases, exhibiting elevated movement rates and dispersals during late-summer, preferential selection for certain habitat types based on season, and no utilization of anthropogenic-resources. One primary concern for large carnivores that have been captive-reared or had prolonged exposure to humans during rehabilitation, is whether they will exhibit natural behaviors after release. Behavior testing in other species has revealed that many traits exhibited in captivity often translate to wild behavior, however this had not yet been investigated for black bears. This study presents the first application of captive behavior tests for the investigation into black bear personality, defined by consistency in the individual differences in behavior across time or context. Through open field, novel object, startle object, and focal-animal sampling, we investigate the potential for personality in six black bear cubs. Results indicate consistency in behavior across five metrics for the bold-shy axis, and eight sampling events measuring responses for the activity axis, thus indicating personality. Analysis to identify correlations to wild activity metrics did not yield strong statistical support, however. Information presented here may provide a framework for future research into black bear personality, its relationship to life-history and ecology, and lend support for rehabilitation practices for orphan bear cubs.
32

Occurrence and Distribution of Invertebrates in Lower Logan River

Erman, Nancy A. 01 May 1968 (has links)
A study of bottom invertebrates on the lower Logan River, Logan, Utah was conducted from June 1966 to July 1967. One objective was to evaluate on a qualitative and quantitative basis the invertebrate populations above and below a sewage entry in the river. Another objective was to study the year round fluctuations in the invertebrate population. The greatest variety of invertebrates was found in the summer. Chironomidae and Baetis were the only two groups found in abundance over the entire year. Populations were reduced during autumn when water levels rose, and they declined even more sharply during the spring flood. At the station below the sewage entry a wide variety of Chironomidae genera were present and Oligochaeta numbers were low.
33

The Influence of Multiyear Drought-Driven Habitat Loss on the Bear Lake Sculpin (Cottus extensus) and the Bear Lake Strain of the Bonneville Cutthroat Trout (Oncorhynchus clarkii utah)

Glassic, Hayley C. 01 May 2018 (has links)
Multiyear drought is expected to increase in occurrence and severity in dry regions across the world, such as the American Southwest, endangering native species and ecosystem health. The effects of multiyear drought are often worsened by human water use for consumption, energy production, and agriculture, which, in lakes and reservoirs, cause reduced lake elevation. Reductions in lake elevation may leave previously submerged habitat stranded along shorelines and make tributaries inaccessible to fishes. Here, we show that decreasing lake elevation, associated with drought and water withdrawal, reduces the availability of shoreline cobble habitat to fishes and increases tributary distance by creating an elevation-specific shoreline habitat map and an elevation-specific tributary channel distance map, respectively. We combined 17-years of fish survey data and lake elevation history with our elevation-specific maps to determine whet her the number of fishes observed and the number of fish hatching are related to drought-driven changes in shoreline habitat and tributary channel distance. We surveyed the shoreline zone of Bear Lake, UT-ID, from full pool to a depth of >18m, totaling 94.86 surveyed km2. As lake elevation decreased >6 m from full pool to the lowest historical elevation, shoreline cobble decreased by >97%, and tributary channel distance increases up to 400% that of full pool. Bear Lake sculpin, a cold-water fish species of concern that relies on cobble for spawning, catch per unit effort decreased by >75% at the minimum cobble area available, and the number of sculpin successfully becoming adults declined by as much as 86%. The number of Bear Lake Bonneville cutthroat trout, a sport fish that relies on connections between tributaries and the lake to complete their life cycle, successfully becoming adults declined by as much as 62%, but annual growth was not related to drought. Our research is an example of the severe consequences of multiyear drought conditions and water withdrawal on lakes and reservoirs, as well as the fishes they support. Indeed, understand the effects of extended drought on aquatic habitats is critical to maintain healthy lakes and reservoirs, to sustain native species, and to maintain the health of popular sport fisheries.
34

Conservation Implications Of Winter-Feeding Policies For Mule Deer In Utah

Peterson, Chris C. 01 May 2008 (has links)
Policies regulating wildlife winter-feeding programs may have long-term impacts on conservation and future management of both target and non-target species. In 2000, the Utah Wildlife Board, upon reviewing input from a series of public regional meetings, adopted a Utah Big Game Winter-Feeding Policy. The Utah Division of Wildlife Resources used this policy to regulate winter-feeding programs for mule deer in northern Utah, 2001-2005. I monitored the program effects on mule deer biology, activity and migration, and winter browse utilization and productivity. While feed rations generally compensated for protein and energy deficiencies, they may overlook mineral deficiencies. To determine if mule deer could select for feeds that contained minerals that may be deficient in native browse, I conducted experimental feeding trials using copper supplements. Feeding program success on increasing mule deer winter survival depends heavily on timely implementation. Therefore, I evaluated the utility of a modified body condition index to use deer-vehicle collision carcasses to monitor herd nutritional status, and applied this information to weather data to assist in determining when to implement winter-feeding programs. Lastly, I surveyed a random sample of Utah stakeholders to determine if the policy developed through the regional meeting process reflected wider public opinion rather than traditional consumptive users. This winter-feeding enhanced body condition, and increased adult female survival. When dynamics of fed and non-fed study groups were modeled over five years, the model predicted both populations were declining, with a lower rate of decline in the fed population. The primary cause of mortality for fed and non-fed groups, deer-vehicle collision, nullified benefits accrued from feeding. Deer may have balanced the effects of sagebrush and bitterbrush toxins with nutrients from feed rations, thus resulting in increased browsing of bitterbrush. Fed deer browsed over less area, and migrated earlier in fall and later in spring. Mule deer also selected a consistent proportion of copper-amended rations, suggesting plain rations are nutritionally inadequate. Although most Utah stakeholders were unaware of Utah's big game winterfeeding policy, most believed winter-feeding was an important mule deer management strategy in Utah. When given a choice between using management funds to support winter-feeding or habitat projects, stakeholders preferred funding habitat restoration.
35

Assessing Plant Community Structure in the Upper Las Vegas Wash Conservation Transfer Area, Nevada: The Influence of Biotic and Abiotic Variables

Croft, Amy A. 01 May 2016 (has links)
Ecological communities are complex, the structure of which is composed of interactions between multiple community characteristics and the abiotic and biotic factors shaping them. Because of this complexity, ecological studies are generally limited in scope and size, often dissecting communities into their component parts to examine them piece by piece. While this might be the most practical method to study communities, this approach often neglects other characteristics that, with their inclusion, would provide a more complete picture of community ecology. The studies described in this dissertation were conducted in an effort to synthesize the complexity that is inherent in ecological plant communities growing on a Mojave Desert bajada. Each study addresses a separate component of community structure, which, taken as a whole, provides a more thorough understanding of arid plant community dynamics. Overall, our results reveal the importance of substrate variables and their role in shaping plant community structure in arid environments. In addition, these investigations provide evidence of the strong role that facilitation plays on this bajada and possibly arid plant communities as a whole. The comprehensive approach described in this dissertation will enable ecologists to gain a more complete understanding of community dynamics and apply this knowledge to various climate change and land management scenarios.
36

Leafhoppers (Cicadellidae) Associated with the Stone Fruit Orchards of Northern Utah

Nielson, Mervin W. 01 May 1950 (has links)
Virus diseases of stone fruit orchards have existed in Utah for more than a quarter of a century and are seriously diminishing the peach and cherry fruit production. Western X of peach, rusty mottle of cherry, wilt and decline of cherry, and little cherry constitute the most economically important stone fruit virus diseases in Utah. Many orchards, particularly in Davis County, have 50 to 83 percent of the trees infected with one or more of the yellow-red viroses. Surveys have shown that the diseases are spreading from 3 to 5 percent each year. It is believed that certain insects are responsible for the natural spread of the virus diesases of stone fruits. Some inconclusive evidence points to leafhoppers as the potential vectors since many cicadellidids are capable of transmitting virus to plants during the feeding process. They have maintained a reputation for being efficient vectors of plant viruses for many years, as well as inducing other types of plant injury. Their adaptable, piercing-sucking mouth parts inoculate plants with filterable viruses taken in from infected plants. They inflict other types of damage to the host by injecting toxic substances. The most sever type of damage, however, is that caused through the virus infection which generally is systemic. The purpose of this investigation was to determine the occurrence, seasonla abundance, and host preference of leafhoppers occurring in the stone fruit orchards of northern Utah. Leafhopper occurrence in plant environs adjacent to the stone fruit orchards was also studied. Studies were made to determine if any correlation existed between leafhopper abundance and percentage of diseased trees in the orchards. Trap studies and surveys seemed to be the most appropriate technique in approaching this problem. The trap studies were conducted in fifteen stone fruit orchards in five counties of norhtern Utah. Surveys were undertaken in most stone fruit growing areas in the northern part of the state.
37

Chlorophyll and Productivity in a Mountain River

McConnell, William J. 01 May 1958 (has links)
Investigation of primary production in streams and rivers has lagged behind similar investigations in marine and lacustrine environments. Recently, however, Odum (1956) has demonstrated methods that allow the estimation of productivity of most moving waters. For reasons discussed later in this paper, Odum's method is not satisfactory for shallow, very rapid rivers as typified by Logan River. The present investigation then was primarily an exploration of a method possibly applicable to measurement of productivity in shallow rapid rivers. Investigation of phases of the ecology and distribution of the main contributors to primary production, the benthic algae, was a necessary corollary to intelligent measurement of primary production in Logan River. A recent review of the knowledge of ecology of river algae (Blum, 1956) summarizes this topic. Most quantitative investigations of river algae have been directly or indirectly concerned with indices of pollution rather than productivity (Jones, 1951) (Reese, 1937) (Patrick, 1949) (Butcher, 1932, 1940, 1945, and 1947). The growth of algae on slides has been a frequently used method of quantitative study, but it is difficult to relate values attained in this fashion to total productivity or standing crop. Statements concerning algal succession and seasonal variation based on counts of algae growing on glass slides in very rapid water appear questionable.
38

The population, habitat, behavioral and foraging ecology of the red-cockaded woodpecker (Picoides borealis) in southeastern Virginia

Miller, Gary L. 01 January 1978 (has links)
No description available.
39

The effects of overwash on the vegetation of a Virginia barrier island

Baumann, Christine 01 January 1978 (has links)
No description available.
40

Foraging Behavior of Nerodia clarkii compressicauda, with Special Reference to Lingual Luring

Hansknecht, Kerry Andrew 01 August 2009 (has links)
Predators use a variety of tactics with which to obtain prey. Here, I describe lingual luring by the mangrove saltmarsh snake (Nerodia clarkii compressicauda), a somewhat unique behavior that involves the use of the tongue to attract fish prey close enough to permit their capture. The lure is characterized by considerable upward curling of the distal portion of the tongue as it protrudes from the mouth. In addition, luring tongue flicks are significantly greater in duration than chemosensory tongue flicks. Both visual and chemical cues are sufficient to stimulate lingual luring, the latter more so than the former. However, both types of cues together have a strong synergistic effect on elicitation of the behavior. Luring behavior presents primarily a visual stimulus, as its frequency was reduced in the dark. Although prey density had no effect on the exhibition of luring by these snakes, prey density did have an effect on their activity level and their choice of foraging sites. N. c. compressicauda was a fairly active forager under the conditions tested in these studies, but its use of a largely sit-and-wait tactic such as predatory luring indicates that this species uses more of a mixed foraging strategy. The foraging behavior of the snakes differed at different levels of habitat structural density, created by using simulated prop roots in a laboratory arena. When no prop-root structure was present, the snakes rarely ventured into open water. However, they spent significantly more time in the water if prop roots were present. Such habitat structure may serve as protection from larger predators that may be impeded by it.

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