Thesis (doctoral)--Delft University of Technology, 2007. / Vita. Includes bibliographical references (p. [99]-110).

Thesis (Ph. D.)--University of Florida, 1993. / Vita. Includes bibliographical references (leaves 587-658).

<p>The success of medusahead (Taeniatherum caput-medusae ssp. asperum) as an invasive exotic grass in the western US is attributed in part to its low palatability. The nutritional context where medusahead grows can be modulated by the use of supplements that increase herbivores? preference for unpalatable feeds. Additionally, positive experiences early in life (with mother, with supplements) can have long-life influences on preference for unpalatable feeds. To test the influence of the nutritional context on medusahead intake, ewes grazed with their lambs during summer of 2013 on medusahead-infested rangeland with (Treatment) or without (Control) the daily provision of an energy-rich supplement. To test for the effect of experience early in life at grazing medusahead on use of this weed later in life, lambs that grazed with their mothers during 2013 (Experienced) were exposed to medusahead (in pens and during grazing) as yearlings during summer of 2014 along with inexperienced (Control) animals. To better understand the unpalatability of medusahead, the fermentation kinetics of medusahead at different phenological stages and particle sizes was assessed. Ewes grazing with their lambs showed low use of medusahead (5% of the grazing events recorded), even when supplemented. Nevertheless, medusahead use increased across the grazing period and utilization was similar to medusahead abundance in the plant community. Use of medusahead by nursing lambs was correlated with that observed by their mothers and lambs utilized medusahead to the same extent either before or after weaning. Yearlings in pens showed low intake of medusahead and a cyclic pattern of intake across days. However, experienced yearlings displayed a more even intake of medusahead across days and a greater gain-to-feed ratio than Control yearlings. All yearlings showed low to nil use of medusahead during grazing. Medusahead had lower fermentation rates than alfalfa hay and fermentation rates declined with plant maturity. Organic matter digestibility for medusahead declined as particle size of the substrate increased, a relationship that explains the low palatability of the weed. These results provide the foundation for grazing treatments aimed at reducing the abundance of the weed or at preventing its spread in rangelands with different levels of medusahead infestations.

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Conservation agencies worldwide are facing rapid, volatile social and ecological change, which is especially problematic for bureaucratic, hierarchical conservation organizations that are designed to be stable and resistant to change. The current science and management paradigm based on Progressive era ideology is proving to be inadequate to deal with this change, and the need for a new paradigm that embraces complexity and uncertainty in our social ecological systems is emerging. The National Park Service (NPS) is one of these organizations that has acknowledged the need to better adapt to a changing environment. An external science committee recommends in Revisiting Leopold: Resource Stewardship in the National Parks (Revisiting Leopold) that the agency transform itself into one that recognizes relationships within social ecological systems at different scales, forms new partnerships, and accepts complexity, uncertainty, and dynamism as integral components of social ecological systems. However, organizational change is challenging due to structural and cultural factors and underlying assumptions that stymie organizational learning and adaptation. The problem addressed in this thesis is that while Revisiting Leopold highlights the need for the organization to adopt a new ideology better suited to complex social ecological systems, the process of transforming this type of agency on an organizational level is difficult. To address this problem and better understand how managers perceive the ideas in Revisiting Leopold, twenty-three semi-structured interviews were conducted with managers across the NPS. In particular, this study evaluates the events, patterns, structures, cultures, and mental models at play within the organization. Several system archetypes and organizational learning disabilities emerged from the data that limit the ability of the organization to embrace a new management and scientific paradigm. This study also contributes to a greater understanding of the NPS as a system, which allows for the identification of leverage points that can be utilized if the NPS chooses to transform itself into this new paradigm.

L’objectif de la thèse a été d’apporter des éléments sur la réaction acrosomique (RA) aviaire afin de mieux comprendre les processus menant à la fécondation et de mieux maîtriser la capacité des spermatozoïdes à être conservés. Nos résultats ont conforté l’hypothèse de l’absence de capacitation chez les oiseaux. De plus, il n’y a pas d’hyperactivation de la mobilité lors de la RA. Seul le Ca2+ s’avère être l’élément indispensable au déclenchement de la RA. L’évaluation de la RA avec des spermatozoïdes conservés à l’état liquide ou après cryoconservation a révélé une évolution différente en fonction du type de conservation. L’étude des voies de signalisation susceptibles d’être impliquées dans le déclenchement de la RA a suggéré l’activation de 3voies, PKA, PI3K et MAPK ERK. Ce travail ouvre de nombreuses perspectives scientifiques vers l’approfondissement des connaissances de la RA chez les oiseaux et sur l’utilisation qui peut en être faite pour mieux maîtriser la qualité des gamètes. / The aim of this work was to provide new information on chicken acrosome reaction (AR) for a better comprehension of the mechanisms leading to this reaction and a better control of the fertilizing potential of spermatozoa after in vitro storage. Our results showed that calcium is the factor absolutely necessary to initiate the AR and supported the hypothesis that chicken spermatozoa do not need to be capacitated. Moreover, motility hyperactivation was not found at the time of AR. Then, we showed that chicken sperm ability to undergo the AR may differ depending on the type of semen storage. Indeed, this ability was dramatically affected by liquid storage, but was submitted to contrasted effect after cryopreservation. Finally, we investigated the potential involvement of several signaling pathways in initiation of the chicken AR and the results showed that the AR could be mediated by activation of the PKA, PI3K and ERK MAPK pathways.

Coarse woody debris (CWD), an essential component of healthy forests, has typically been defined as dead and down, large woody material. Quantification of this resource provides a useful metric for assessing wildlife habitat, fuel loading, and more recently, carbon sequestration. Although many CWD sampling methods exist, accurate estimation is difficult and expensive. Double sampling incorporates auxiliary data that is positively correlated with the attribute of interest as a means of reducing sampling costs and/or increasing estimation precision. The present study investigated double sampling applications to the common CWD sampling technique, line intersect sampling (LIS). We identified aggregate length as a potential auxiliary variable for estimating aggregate volume and abundance of CWD. However, further analysis indicated that the cost difference of the sampling phases, coupled with the correlation of the variables was not sufficient to warrant double sampling in the study area. Further investigation is needed to develop accurate and efficient CWD sampling methods with widespread applicability.

Many tourism destination managers know who their visitors are and how they are perceived by them. However, when new destinations begin to take shape, understanding these perceptions and meeting the expectations of visitors can be a difficult task. Destination image provides the ability to explore the perceptions of visitors at a tourism place. One such place the Beartooth Highway in south-central Montana and north-central Wyoming is a scenic byway that reaches nearly 11,000 feet in elevation. Previously, little to no research has been conducted regarding travelers that frequent this region. The purpose of this study was to understand the destination image and economic impacts of nonresident travelers on the Beartooth Highway. Nonresidents were travelers who did not live in the counties of the Beartooth Highway (Park County, MT, Carbon County, MT and Park County, WY). A two-part survey method was implemented. First, an on- site visitor survey was conducted for all travelers along the highway. Second, a mailback survey was given to all nonresidents travelers. The survey included statements about the Beartooth Highway, trip spending categories, motivations for traveling the highway, and activities participated in while visiting. Visitors were intercepted at the three exit points of the Beartooth Highway. In total, 4,285 nonresident visitors were intercepted along the highway. Of those, 3,251 nonresidents were given mailback surveys. The survey was completed and returned by 1,473 respondents for a response rate of 45 percent. Results from the study show that visitors perceive the Beartooth Highway in positive light. Forty-four percent of respondents stated they were first-time visitors. Moreover, visitors who had a higher degree of loyalty to the destination had significant differences in many of the cognitive and affective image variables. Nonresident spending contributed over $50 million in economic impacts to the local communities in the four month time period. Because visitors perceive the place as a destination rather than simply a highway, it is recommended that more collaborative management be implemented. The highway should also be marketed and managed with these results in mind to ensure the preservation of the unique characteristics and qualities of the region.

Bailey, Daniel, M.S., December 2012 Resource Conservation COLLABORATIVE CONSERVATION OF TAIMEN THROUGH EDUCATION AND AWARENESS KHOVSGOL AIMAG MONGOLIA Chair: Dr. Keith Bosak ABSTRACT: Siberian taimen (Hucho taimen) populations in northern Mongolia (the state of Khovsgol aimag) are threatened by illegal poaching, habitat loss, mining and recreational fishing. Taimen are the worlds largest salmonid, historically reaching lengths of 6.5 ft. and weighing as much as 200 lbs This unique species of fish is incredibly slow-growing, long-lived (up to 40 years) and late to reach sexual maturity (5-7 years). These characteristics -- coupled with overuse and habitat loss -- have resulted in a drastic species decline throughout its native range. In Mongolia alone, the taimens historical range has been reduced by nearly twenty per cent (Hogan, Z; Jensen, O; Rand, P; Weiss, S; IUCN Red Listing 2012). Taimen have been listed as endangered under the Mongolian, Russian and Chinese Red Lists. The intent of this project is to address taimen conservation through an educational campaign targeted at foreign and domestic anglers. The Spirit of the River (SOR) project addresses long-term protection of this rare and threatened fish. An education and awareness campaign was implemented in Murun (the provincial capital of Khovsgol aimag), the Murun regional airport and the Chinggis Khan International airport in the Mongolian capital of Ulaanbaatar. The SOR campaign targets foreign and domestic anglers who come to Khovsgol aimag to fish for taimen.

There is a wide range of goods and services being provided to humans by water resources (e.g. hydropower and recreation), but there is also a diversity of stakeholders that require or desire these benefits, also known as water-based ecosystem services, for everyday life. Land managers working for the United States Department of Agriculture Forest Service in the semi-arid Rocky Mountain Region are tasked with the difficult job of managing scarce water resources in the face of competing human pressures and natural forces (e.g. climate change). Water management decisions on public lands can potentially impact the availability of a wide range of benefits derived from water to a wide range of stakeholders. This project aimed to inform policy-makers and land managers about the range of benefits people derive from water within and flowing from the Shoshone National Forest (SNF), and the importance of those water benefits to stakeholders in northwest Wyoming. Additionally, this project aimed to understand the perceptions of stakeholders regarding the threat of climate change, and other factors, to their ability to receive certain water-based ecosystem services. The use of literature review, focus groups, and pilot tests helped to identify 34 water-based ecosystem services being derived from the SNF. An understanding of stakeholder preference for those 34 ecosystem services was obtained through the use of a preference elicitation method called Q-methodology, which was administered to 96 stakeholders covering a broad range of interests. Factor analysis of the 96 surveys yielded four major perspectives that explain, in a nuanced fashion, 48% of the study variance. The four viewpoints were named the environmental perspective, agricultural perspective, Native American perspective, and recreation perspective. The preferences for each of the four viewpoints with regard to water-based ecosystem services are presented holistically, however, each of the viewpoints is partly defined by two most important ecosystem services. Those most important water-based ecosystem services were water quality (most important to two different viewpoints), household/municipal use (most important to two different viewpoints), Native American cultural and spiritual values, commercial irrigation, river-based fishing, and biodiversity conservation. The threat of climate change to the ability of stakeholders to receive their most important water-based ecosystem services was acknowledged by the majority of stakeholders but, in many cases, there was skepticism that climate change is anything more than a natural trend. Additionally, stakeholders were concerned about water quality, federal and state government management and regulations (e.g. reservoirs and in-stream flow management), and other competing uses impacting their ability to receive their most important ecosystem services.