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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.
171

A metapopulation dynamics model for black bear recolonization in the Trans-Pecos region of Texas

New, Cherie Lynn 10 October 2014 (has links)
<p> West Texas, especially the Trans-Pecos region, mainly consists of desert shrubs and grasslands with patches of higher elevation (1,500 &ndash; 2,000 m) mountain ranges. Black bears (<i>Ursus americanus</i>) were extirpated from this area by the 1940s because of predator control and over hunting. In the 1980s, black bears returned to west Texas in a natural recolonization movement from Mexico, where they had survived. The black bear populations of the Trans-Pecos region and northern Mexico fit a mainland-island metapopulation model. Based on previously published research on this recolonization event, I identified several likely habitat recolonization sites and corridor routes for use in predicting possible black bear dispersal throughout the area. Then, using these corridor and recolonization scenarios, I produced a black bear metapopulation model for the Trans-Pecos region.</p><p> The possible habitat recolonization site map was created by combining 2 habitat suitability index (HSI) maps and using these HSI maps to define 'core' and 'useable' black bear habitat within the Trans-Pecos region. Using these locations, along with dispersal probabilities and black bear demographic parameters, I created a corridor dispersal map of the area using the program Circuitscape.</p><p> The metapopulation model was created using STELLA modeling software. Each recolonization location in the Trans-Pecos region (Big Bend National Park, Black Gap Wildlife Management Area, and the Davis Mountains) has its own black bear subpopulation. The metapopulation model is a stochastic compartment model based on a yearly time step (&Delta;<i>t</i> = 1 yr). This model was tested for the effects of: carrying capacity per site, immigration rates from Mexico, rates of dispersal from Black Gap Wildlife Management Area to the Davis Mountains, and the recovery time for the area after complete extirpation from the Trans-Pecos. This information will help local biologists conserve and manage these returning black bears in the Trans-Pecos region. </p>
172

Plant community response to reduced mowing regimens along highway right-of-ways in Northeastern Mississippi

Entsminger, Edward David 10 June 2014 (has links)
<p>I investigated percent coverage, plant height, species richness, and woody stem density in plant communities in ten study plots during spring and fall (2010&ndash;2012) within 3 different treatments (continual mowings, one fall mowing, and one fall mowing with native wildflower seeds) on Highway 25 right-of-way in Oktibbeha and Winston counties, Mississippi. I recorded 277 plant species including native and non-native forbs, legumes, grasses, rushes/sedges, and woody plants. Non-native agronomic grasses exhibited greatest coverage greater than 90 percent occurring in all treatments. Percent coverage of plants less than 0.46m height category exceeded 100 while, greater than 0.46m plant height categories averaged 55 percent. Woody stem density ranged from 7,772 year 1 to 10,025 stems/hectare year 2. I detected no significant differences in plant height or woody stems among treatments. One mowing per year retained agronomic plant cover for erosion control and annual cost savings up to 75 percent for roadside maintenance. </p>
173

Variability in delta13C and delta 15N values of Steller sea lion pup vibrissae| Implications for diet and foraging studies

Siess, Kourtney 10 June 2014 (has links)
<p> During the 1970s to the 1990s, Steller sea lions (<i>Eumetopias jubatus</i>) in Alaska declined severely, resulting in the western stock's listing as endangered under the United States Endangered Species Act. The localized depletion of their main food source around rookeries and haul out sites was the primary cause of their depletion. The western stock has still not recovered to historical levels. Therefore, scientists have continued to study Steller sea lions diet and foraging habits. One approach has been through stable isotope analysis of their various tissues. Analysis of their vibrissae, or whiskers, provides an exact record of an individual's diet from birth to the present. However, scientists so far have only measured stable isotope values of a single vibrissa from an individual, assuming no significant difference among vibrissae within or between cheeks. They have not accounted for the possibility of variable stable isotope accumulation in an individual's different vibrissae. In this study, I tested the assumption of no significant individual variability among vibrissae by examining the &delta;<sup>13</sup>C and &delta;<sup> 15</sup>N values in all of the vibrissae on five Steller sea lion pups recovered in Alaska. &delta;<sup>15</sup>N values did not differ between vibrissae on a cheek or between vibrissae from left and right cheeks. The &delta;<sup> 13</sup>C values did not differ between vibrissae within cheeks; however, &delta;<sup> 13</sup>C values were significantly different between the left and right cheeks of Lowrie Island Pup and PWS 29 Pup. This between cheek variation is most likely due to small sample size rather than different stable isotope incorporation. The lack of &delta;<sup>15</sup>N value variation within or between cheeks, as well as the lack of &delta;<sup>13</sup>C variation within cheeks, supports the assumption that stable isotope accumulation is similar between all vibrissae and validates sampling protocols of previous studies collecting just the longest, thick vibrissa from a Steller sea lion. More studies similar to this one are needed to verify these findings and to look at variability in stable isotope incorporation of juvenile and adult Steller sea lion vibrissae as well as other mammal species.</p>
174

Ringtail distribution, dermatoglyphics, and diet in Zion National Park, Utah,

Roadman, Adrian Argie 03 March 2015 (has links)
<p> Current scientific knowledge of the ringtail (<i>Bassariscus astutus </i>) is limited, thus impeding appropriate management decisions. Ringtails in Zion National Park, Utah, are rarely seen, but are involved in increasing occurrences of negative interactions with park visitors and employees such as food theft and denning in buildings, interactions which are harmful to both parties. To manage this conflict, an update to the general knowledge about the status of the population is required as the only previous study on ringtails in this area was conducted in the 1960s. Using noninvasive techniques provides dependable large-scale population information. I used two noninvasive detection methods in combination to establish a robust occupancy estimate of the ringtail population in Zion National Park. Ringtails were detected in 2 of 3 focus areas in the park, but at low densities. This study included the development of a novel method to individually identify ringtails by their footprints. I used the Interactive Individual Identification System (I3S) software to determine if individuals could be identified using the pattern formed by papillae and ridges of the footpad. Ringtails' footpad prints consistently resulted in a unique pattern recognizable by simple visual analysis and a computer-aided analysis of the prints in a database; however more research is needed for the applicability using field data. Ringtail densities were highest in the areas of greatest human activity. The proximity to humans may be impacting ringtail diet and consequently their health. I collected scat in areas of high and low human use to quantify the change in diet resulting from food acquired around human establishments. Ringtails living in areas of high human activity exhibited a change in diet, including the presence of human trash such as foil and plastic; this has implications for ringtail health and human safety. Ringtails acquiring food from human sources may increase their activities around buildings and areas with high human activity, resulting in an increased chance of direct and indirect human-ringtail interactions. Active management of human activities and regular building maintenance is required in the future to decrease negative consequences of ringtail use and presence in areas of high human activity.</p>
175

Abundance, survival, and breeding probabilities of the critically endangered waved albatross

Street, Phillip A. 15 February 2014 (has links)
<p> The Gal&aacute;pagos Archipelago is recognized internationally as a unique eco-region, and many of the species that inhabit these islands can be found nowhere else on Earth. The Ecuadorian government recognized the value of this ecosystem, and, beginning in 1959, they designated 97% of the Archipelago as Ecuador's first National Park. The Charles Darwin Foundation also was founded in 1959 and, since then, the Park Service and the Foundation have worked towards preserving the Gal&aacute;pagos' unique flora and fauna for future generations. The waved albatross (<i>Phoebastria irrorata</i>) is the largest bird species found in the Gal&aacute;pagos Archipelago and was recognized as an iconic species early in the Park's history; it is the only tropical albatross. This species spends the majority of its life foraging at sea and is an important predator in the Humboldt Current off of the coast of South America. With the exception of a few pairs, this albatross breeds entirely on the southeastern most island of the archipelago, Espa&ntilde;ola. Tourists visit Espa&ntilde;ola every year to watch the elaborate courtship dances of this species, and albatrosses in general have been the foci of legends among sailors for centuries. </p><p> M.P. Harris (1969) began banding waved albatross as early as 1961, marking the beginning of a long-term monitoring program with a focus on estimating age-specific first-time breeding, abundance, and survival. This initial effort resulted in the first estimates of abundance and survival for the waved albatross (Harris 1973). Following these initial estimates, the population size of the waved albatross has been estimated in 1994 (Douglas 1998), 2001 (Anderson et al. 2002), and 2007 (Anderson et al. 2008). These estimates suggest that the population has been declining since 1994. Motivated by this apparent decline, Awkerman et al. (2006) investigated survival and concluded that survival estimates from 1999-2005 were lower than average survival from 1961-1970 (Harris 1973). Today, the waved albatross is considered critically endangered, with bycatch in artisanal longline fisheries and the increased occurrence of El Ni&ntilde;o-Southern Oscillation events thought to be contributing to these observed declines in survival and abundance. Given these observed declines in the waved albatross, the importance of the species in the ecosystem, and its intrinsic value in terms of biodiversity, continued monitoring and analysis efforts are needed to evaluate trends over time, and to gauge the effectiveness of management actions. My thesis is focused on these topics. </p><p> In Chapter 1:, I describe a framework to estimate abundance of wildlife populations, apply this framework to estimate population size of the waved albatross at a major breeding colony on Espa&ntilde;ola Island, and I conclude by providing recommendations for future island-wide surveys of this species. </p><p> In Chapter 2:, I revisit the dataset collected by M.P. Harris and the Gal&aacute;pagos National Park from 1961-1981 as well as a more recent dataset collected by K.P. Huyvaert and colleagues. I analyzed these datasets in a multistate mark-recapture framework to estimate and compare estimates of adult survival as well as other important demographic parameters that have not yet been evaluated for this species. </p><p> Bycatch from fisheries and extreme weather events have influenced survival and breeding probabilities of many pelagic seabird species worldwide. Lower adult survival of the waved albatross is thought to be associated with bycatch in the small-scale fishery located off of the coasts of Peru and Ecuador as well as with El Ni&ntilde;o-Southern Oscillation events. Previous efforts to document these threats have not formally considered that a variable proportion of the population does not breed every year or that different life history stages may have different survival rates. </p><p> The results from Chapter 1 suggest a continued decline in the principal breeding population of the waved albatross since 1994, and Chapter 2 shows indirect evidence that this decline may be linked to higher mortality associated with recent documented increases in small-scale longline fishing effort off of the coast of South America. Outside of the Galapagos Marine Reserve where fishing is heavily regulated by the Galapagos National Park Service, little is done to directly manage artisanal fishing operations off of the coasts of Peru and Ecuador. Conservation initiatives recognizing the environmental impact of fishing in this zone have been promoting reduction of seabird bycatch by educating local fishermen. Despite these conservation efforts, the results from my thesis suggest a continued population decline for this critically endangered species and additional mitigation may be needed for the persistence of the waved albatross.</p>
176

The ecological knowledge of Belcher Island inuit : a traditional basis for contemporary wildlife co-management

Nakashima, D. J. January 1991 (has links)
This thesis focuses upon the traditional ecological knowledge of southeastern Hudson Bay Inuit. It provides a detailed assessment of Inuit use and knowledge of a single species, the Hudson Bay Eider (Somateria mollissima sedentaria). Data collected on Inuit classifications of animals reveal the highly-ordered systems whereby Inuit structure their extensive knowledge of the biological diversity of their environment. A lexicon of Inuktitut terms illustrates the refinement of their anatomical knowledge, while detailed data on one anatomical element, the eider skin, serve to indicate the considerable volume of information lying behind these labeled categories. Furthermore, Inuit knowledge of eider ecology provides exacting biogeographical information and identifies important ecological patterns and processes for the species. These findings run counter to preconceptions about traditional knowledge which linger in the wildlife professionals' milieu. Neither anecdotal, narrowly pragmatic, unverified nor non-ecological, traditional knowledge provides a sound argument for greater Native autonomy in wildlife management.
177

Conservation of mule deer in the eastern Sierra Nevada

Ferranto, Shasta P. January 2006 (has links)
Thesis (M.S.)--University of Nevada, Reno, 2006. / "December, 2006." Includes bibliographical references (leaves 126-129). Online version available on the World Wide Web.
178

Population management of Raphanus raphanistrum L. (wild radish) by regulating seed production /

Madafiglio, Gregory Peter. January 2002 (has links)
Thesis (Ph.D.) -- University of Western Sydney, 2002. / "A thesis submitted for the degree of Doctor of Philosophy (Ph.D.) in the Centre for Landscape and Ecosystems Management, University of Western Sydney ... May 2002" Includes bibliography (leaves 159-177) and other bibliographical references.
179

Modeling for threatened and endangered species management the Columbia Basin pygmy rabbit and the Greater sage grouse in Washington /

Zeoli, Leonard Frank, January 2008 (has links) (PDF)
Thesis (Ph. D.)--Washington State University, August 2008. / Includes bibliographical references.
180

The development of multi-level governance for the management of polar bears in Nunavut Territory, Canada

Dowsley, Martha Gwynne McCall. January 1900 (has links)
Thesis (Ph.D.). / Written for the Dept. of Geography. Title from title page of PDF (viewed 2008/05/09). Includes bibliographical references.

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