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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.
141

Factors influencing diet composition of beef cattle grazing mixed conifer mountain riparian areas

Darambazar, Enkhjargal 10 October 2006 (has links)
Two trials were conducted to evaluate changes in the quantity, quality, and moisture of available forage in the pasture, and shrub utilization by cattle during a 30-d late summer grazing period (Trial 1) and the effect of cow age (experience) on grazing distribution and diet composition (Trial 2) in mountain riparian areas. In the trial 1, a pasture (44.7 ha) in the Catherine Creek site at OSU���s Hall Ranch in northeast of Oregon was grazed with 30 yearlings and 30 mature cow/calf pairs from early August to early September in 2001, and from late July to late August in 2002. Sampling dates were d 0, d 10, d 20, and d 30 of the grazing period. The forage availability before grazing was 1058 kg/ha and declined to 323 kg/ha at the end of the grazing period (P<0.10). Grasses dominated the pasture, followed by forbs, grasslikes, and shrubs. Kentucky bluegrass was the most prevalent forage species followed by timothy, sedges, and common snowberry. The highest percent disappearances of forage species was (83.7-92.7%) observed with quackgrass, western fescue, California brome, redtop, and heartleaf arnica, though their initial contributions to the available forage were less than 5%. High levels of shrub utilization were observed from d 20 through the end of the grazing period (45% for willow and 59% for alder). Forbs and shrubs did not vary in moisture content between the 10 d intervals and across the years averaging 59% and 61%, respectively (P>0.10). In contrast, the moisture content of grasses were over 50% at the beginning of the grazing period but declined dramatically to 34% from d 10 to d 20. Likewise, forbs and shrubs were higher (P<0.05) than grasses in CP (11, 14, and 6%, respectively) and IVDMD (58, 49, and 42% respectively). In summary, our results suggest that cattle grazing late summer riparian pastures will switch to intensive shrub utilization when grasses decline in quality and quantity, and forbs decline in quantity. In the trial 2, thirty first calf heifers, and thirty mature cows were randomly assigned to four pastures (15 head per pasture, average 21.5 ha) in the Milk Creek site of Hall Ranch from late July to early September of 2000 and 2001. Botanical composition of diets was determined by analyzing the feces from 10 animals (5 per pasture) in each treatment during the fourth week of the trial using the microhistological procedure. Correction factors were calculated for the 22 major plant species. First calf heifers had higher portions of grasses (75% versus 71%; P<0.05), but lower portions of shrubs and trees (9% versus 13%; P<0.10) as compared to mature cow diets, respectively. On an individual species basis, ponderosa pine consumption was a major contributor with mature cows consuming greater quantities (P<0.10) than first calf heifers. In summary, mature cows seem to have selected diet less in the amount of grasses and more in the amount of shrubs and trees as compared to younger cows. / Graduation date: 2004
142

Markets and competition in private and public campground sectors of Oregon : implications from Oregon campground inventories and the 1997 Campground questionnaire

Newton, Lydia 22 May 1998 (has links)
This study explores private and public campground markets in Oregon. A profile of private and public campgrounds, their prices, location, and amenities, served as the supply side statistics while responses from the 1997 Campground Questionnaire provided data for demand of Oregon campgrounds. The questionnaire inquired about respondents' last camping trip in Oregon, where they camped, how much they paid, the facilities available, the activities in which they participated, socioeconomic attributes, and included a dichotomous choice contingent valuation (CV) question. These data were used to statistically analyze differences in the supply and demand for the private and public campground sectors. First, the inventory was examined using OLS to estimate the effects of campground amenities and location on user fees charged at different campsite types at private, federal, and state campgrounds. Second, I used the survey data (i.e., respondent profiles and campground attributes) to estimate substitution probabilities among campsite type and campground ownership using a nonlinear multinomial logit model. Questionnaire information was also utilized to test for market segmentation and identify the user groups' characteristics. Finally, I utilized responses to the CV question to determine the amount of consumer surplus for Oregon state parks. The significant inventory results were as follows. The model predicted that tent sites at state campgrounds are more expensive, on average than tent sites at private campgrounds. National Forest campgrounds located in eastern Oregon, on average, are less expensive than those at private and state campgrounds. The survey statistical results predicted that users of tent sites appear to be the least price sensitive, for both private and public markets. Recreational vehicle owners are more price sensitive than tent owners in both the private and public markets. Furthermore, those campers that choose a full hookup site are the most likely to use the OPRD reservation system. The contingent valuation data revealed, through linear regression, that campers would be willing to pay $44.71 more than they currently pay for a camping trip if the payment were used to improve and maintain state parks. This research is intended to contribute statistical reference for user fees and general market information to the Oregon Parks and Recreation Department. / Graduation date: 1999
143

Pikas, Grasslands, and Pastoralists: Understanding the Roles of Plateau Pikas in a Coupled Social-Ecological System

January 2016 (has links)
abstract: The plateau pika (Ochotona curzoniae), a small burrowing lagomorph that occupies the high alpine grassland ecosystems of the Qinghai-Tibetan Plateau in western China, remains a controversial subject among policymakers and researchers. One line of evidence points to pikas being a pest, which has led to massive attempts to eradicate pika populations. Another point of view is that pikas are a keystone species and an ecosystem engineer in the grassland ecosystem of the QTP. The pika eradication program raises a difficult ethical and religious dilemma for local pastoralists, and is criticized for not being supported by scientific evidence. Complex interactions between pikas, livestock, and habitat condition are poorly understood. My dissertation research examines underpinning justifications of the pika poisoning program leading to these controversies. I investigated responses of pikas to habitat conditions with field experimental manipulations, and mechanisms of pika population recovery following pika removal. I present policy recommendations based on an environmental ethics framework and findings from the field experiments. After five years of a livestock grazing exclusion experiment and four years of pika monitoring, I found that grazing exclusion resulted in a decline of pika habitat use, which suggests that habitat conditions determine pika population density. I also found that pikas recolonized vacant burrow systems following removal of residents, but that distances travelled by dispersing pikas were extremely short (~50 m). Thus, current pika eradication programs, if allowed to continue, could potentially compromise local populations as well as biodiversity conservation on the QTP. Lethal management of pikas is a narrowly anthropocentric-based form of ecosystem management that has excluded value-pluralism, such as consideration of the intrinsic value of species and the important ecological role played by pikas. These conflicting approaches have led to controversies and policy gridlock. In response, I suggest that the on-going large-scale pika eradication program needs reconsideration. Moderation of stocking rates is required in degraded pika habitats, and Integrated Pest Management may be required when high stocking rate and high pika density coexist. A moderate level of livestock and pika density can be consistent with maintaining the integrity and sustainability of the QTP alpine steppe ecosystem. / Dissertation/Thesis / Doctoral Dissertation Biology 2016
144

Evaluating the Impact of Land Cover Composition on Water, Energy, and Carbon Fluxes in Urban and Rangeland Ecosystems of the Southwestern United States

January 2017 (has links)
abstract: Urbanization and woody plant encroachment, with subsequent brush management, are two significant land cover changes that are represented in the southwestern United States. Urban areas continue to grow, and rangelands are undergoing vegetation conversions, either purposely through various rangeland management techniques, or by accident, through inadvertent effects of climate and management. This thesis investigates how areas undergoing land cover conversions in a semiarid region, through urbanization or rangeland management, influences energy, water and carbon fluxes. Specifically, the following scientific questions are addressed: (1) what is the impact of different urban land cover types in Phoenix, AZ on energy and water fluxes?, (2) how does the land cover heterogeneity influence energy, water, and carbon fluxes in a semiarid rangeland undergoing woody plant encroachment?, and (3) what is the impact of brush management on energy, water, and carbon fluxes? The eddy covariance technique is well established to measure energy, water, and carbon fluxes and is used to quantify and compare flux measurements over different land surfaces. Results reveal that in an urban setting, paved surfaces exhibit the largest sensible and lowest latent heat fluxes in an urban environment, while a mesic landscape exhibits the largest latent heat fluxes, due to heavy irrigation. Irrigation impacts flux sensitivity to precipitation input, where latent heat fluxes increase with precipitation in xeric and parking lot landscapes, but do not impact the mesic system. In a semiarid managed rangeland, past management strategies and disturbance histories impact vegetation distribution, particularly the distribution of mesquite trees. At the site with less mesquite coverage, evapotranspiration (ET) is greater, due to greater grass cover. Both sites are generally net sinks of CO2, which is largely dependent on moisture availability, while the site with greater mesquite coverage has more respiration and generally greater gross ecosystem production (GEP). Initial impacts of brush management reveal ET and GEP decrease, due to the absence of mesquite trees. However the impact appears to be minimal by the end of the productive season. Overall, this dissertation advances the understanding of land cover change impacts on surface energy, water, and carbon fluxes in semiarid ecosystems. / Dissertation/Thesis / Doctoral Dissertation Civil, Environmental and Sustainable Engineering 2017
145

Boundaries and Bridges in Rangeland Social-Ecological Systems: Studies of Collaboration, Innovation, and Information Flow

Meredith, Gwendŵr R. 01 December 2019 (has links)
Public rangelands are managed by a mixture of federal, state, and local governments. Often, these groups are charged with managing adjacent lands that are part of the same greater landscape. To do this effectively, communication and collaboration is required. This dissertation examines federal, state, and local agencies’ level of communication through three projects. The first project examined barriers to agencies adopting management tools from each other. I found that individuals within agencies were mainly staying within their own agency when seeking advice, so individuals were not communicating about tools or their findings across agencies. Furthermore, agency policies and fear of being sued restricted individuals’ ability to adopt management tools. The second project studied how land and wildlife managers in Southeastern Utah work together, or not, in managing mule deer populations that migrate to and from land managed by different agencies. I found that managers are working together to manage mule deer populations, but there are only a few individuals that tie everyone together. The third project looked at how federal, state, and local governments work together to rehabilitate lands after a wildfire that burned parts of Southwestern Idaho and Southeastern Oregon. I found that policy decisions at the federal level can heavily impact who works together and when. All three projects revealed that there are still barriers to federal, state, and local governments working together to manage the same landscape. However, the results from this dissertation also highlight opportunities for bridging the gap between agencies and, ultimately, improving management of rangelands.
146

INCLUDING HERSTORY IN HISTORY -A gender-based policy analysis of Participatory Rangeland Management in relation to Participation, Influence and Empowerment

Nilsson, Aila January 2020 (has links)
This thesis examines how preparatory, policy and review documents of the Participatory Rangeland Management (PRM) in East Africa, problematize and represent the ‘problems’ which resulted in the design of the development program. The focus is on how these problematizations can hinder or facilitate participation, influence and empowerment of women and marginalized groups in decision-making processes. The findings are based on a gender-based policy analysis undertaken of five documents written by the NGOs involved in the planning and implementation of PRM in Ethiopia, Kenya and Tanzania. A conceptual framework measuring the level of participation, empowerment and influence was constructed to assess the policies and their possible outcomes. The document analysis showed that the implicit ‘problem’ themes identified appeared to be that communities were unmodern, undeveloped, and had under-representation of women and pastoralists in rangeland management. These problematizations seem to originate from a development discourse characterized by solutions focussing on ‘modernization’ and ‘technical fixes’. These pre-conceived ideas of the ’problems’ call for more communication and inclusion of community groups in problem formulation and program design. The analysis further revealed that expert-assisted and gender-mainstreaming initiatives such as the PRM could have a positive impact on the level of participation, influence, and empowerment of women. When training was carried out for both women and men by the PRM to raise awareness of women’s rights, it resulted in an increased number of women participating in activities. However, gender-mainstreaming should not stop with participation, it should be further developed towards influence and empowerment. The PRM could consider promoting a change of power relations by combining efforts to demonstrate the benefits of meaningful consultations to decision-makers and efforts to enhance the knowledge and skills of marginalized groups so that they can better engage with these decision-makers. Furthermore, there is a need to expand the discussion on how to design gender-mainstreaming policies and practices, without labelling women as one.
147

Evaluation of restoration and management actions in the Molopo savanna of South Africa :|ban integrative perspective / Christiaan Johannes Harmse

Harmse, Christiaan Johannes January 2013 (has links)
The loss of ecosystem resilience and rangeland (often referred to as veld in South Africa) productivity is a major problem in the semi-arid Savanna environments of southern Africa. The over-utilization of rangelands in the Molopo region of the North- West Province in South Africa has resulted in profound habitat transformations. A common regional indicator of rangeland degradation is the imbalance in the grasswoody ratio, characterized by a loss of grass cover and density with increased shrub or tree density. This can result in major reductions of rangeland productivity for the grazing animal, forcing land users to apply active or passive restoration actions to improve rangeland condition, control the thickening of woody species (bush thickening), mitigate economic losses and restoring the aesthetical value of the Savanna environment for ecotourism and game hunting aspects. This study formed part of the multinational EU-funded PRACTICE project (“Prevention and restoration actions to combat desertification: an integrated assessment”). The first aim of the study was to evaluate locally applied restoration actions using a participatory approach, followed by interviews with certain stakeholders that formed part of a multi-stakeholder platform (MSP) related to the livestock and game farming community in the Molopo. Participants of the MSP ranked indicators according to their relative importance regarding the restoration actions on an individual basis. The individual ranking results were combined with quantitative bio-physical and qualitative socio-economic measurements for each indicator in a multi-criteria decision analysis (MCDA), whereby the alternative actions were ranked according to their relevancy and performance. The results were then shared with members of the MSP in order to stimulate discussion among the members and contribute to the social learning of the project outcome. The overall positive response and acceptance of results by members of the MSP changed the perceptions and objectives of the land users regarding rangeland management. This type of participatory assessment was therefore found to be very promising in helping to identify more sustainable actions to mitigate rangeland degradation in the Molopo Savanna region. There is, however, still an urgent need to create legal policy frameworks and institution-building, to support local-level implementation in all socio-ecological and economic settings, particularly in communal areas. The second aim was to evaluate the effect of two chemical bush control actions (chemical hand- (HC) and aeroplane control (AC)) as well as rotational grazing (RGM) on the Molopo Savanna vegetation. Results show that rangeland productivity, i.e. forage production and grazing capacity, was found to be negatively related to the woody phytomass in the savanna system studied. Bush thickening influenced grass species composition which was commonly associated with a decline in the abundance of sub-climax to climax grasses, respectively. All three actions (HC, AC & RGM) significantly reduced the woody phytomass and increased forage production and grazing capacity. Although AC resulted in the highest reduction of woody phytomass, the highest forage production and grazing capacity was found under RGM. The second highest grazing capacity was found in HC sites, which was due to a high abundance of perennial, palatable climax grass species. Results from this study also show that the patterns and compositions of grass species, grass functional groups (GFGs) and woody densities indicated by RGM and chemical HC, best resemble a productive and stable savanna system that provides important key resources to support both grazing and browsing herbivores. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2014
148

Property Rights, Risk and Development: <br />Community-Level Range Management in Niger

Vanderlinden, Jean-Paul January 2001 (has links) (PDF)
This dissertation contributes to the debate on Common Pool Natural Resources (CPNRs) through the analysis of a specific case study: rangeland in southwest agro-pastoral Niger. The management of CPNRs is the subject of a lively debate pertaining to the property rights regime that may accompany CPNR management. This dissertation shows that this debate may very well be the consequence of disciplinary preconceptions that are linked with disciplinary paradigms. By approaching the case study with an interdisciplinary approach, this dissertation shows how interdisciplinary research may contribute to the avoidance of “universalism” (i.e., one property rights regime fits all CPNRs) with regard to CPNR management. <br />The case study is approached by using three different conceptual frameworks in order to explore five research questions. A first framework, econometric modelling, is used to explore the following two questions: “what are the determinants of rangeland use in southwest agro-pastoral Niger?” and “what are the determinants of livestock mobility?” A second framework, event chronology analysis, is used to explore the following two questions: “what is the impact of rainfall shocks on rangeland property rights?” and “is the marginalization of the pastoral space avoidable and reversible?” A third framework, network analysis, allows for the exploration of: “do traditional local institutions have the capacity to play a role in the management of rangeland?” The analysis and discussion of these research questions point to the fact that community-level rangeland management in southwest agro-pastoral Niger is a definite possibility. Nevertheless, it will be possible only if livestock raising practices are strong in the two traditional producer groups: agriculturalists and pastoralists. Community-level management will, therefore, have to be rooted in the community that is constituted by the users of the rangeland.<br />Finally this dissertation concludes by stressing the results in terms of rangeland-management policy for Niger, in terms of the interdisciplinary analysis of CPNR, and in terms of conducting interdisciplinary research in general.
149

Selecting and evaluating native forage mixtures for the mixed grass prairie

2013 April 1900 (has links)
Diverse native seed mixtures have many benefits for prairie restoration or seeded pastures. In natural grasslands, species naturally coexist with hundreds of other species in complex communities. Commercial seed mixtures rarely contain more than a small number of species, often with haphazard ratios of the component species. Thus there is no natural template for combining selected species into an optimally productive community and there is limited knowledge on how to compose a suitable species mixture. Identifying which features of a community drive increased productivity may aid in screening species and community compositions, leading to mixtures that are more specifically designed to be stable, and highly productive for the region. There is renewed interest native species as they have the potential to provide non-invasive, productive, and drought resistant rangelands that may prove more sustainable. Seven species with high agronomic potential and a broad native geographic distribution were selected for testing including: nodding brome [Bromus anomalus (Coult.)], blue bunch wheatgrass [Pseudoregneria spicata (Pursh)], western wheatgrass [Pascopyrum smithii (Rydb.)], side oats grama [Bouteloua curtipendula (Michx.)], little blue stem [Schizachyrium scoparium (Michx.)], purple prairie clover [Dalea purpurea (Vent.)], and white prairie clover [Dalea candida (Willd.)]. The early productivity and nutritional quality of these species was determined in simple mixtures in two field sites: Saskatoon and Swift Current. In the field sites the mixtures included all seven monocultures, 21 two-species mixtures and a mixture with all species. Productivity may be driven by the species richness, functional group richness, and species evenness of the community, the abundance and occurrence of particular species or functional groups, and average plant trait values within the community. Therefore, identifying the features of a community that drive increased productivity and applying them as predictive tools may aid in screening species and community compositions. Many complex mixtures of the species were planted in greenhouse experiments to determine the strongest drivers of productivity for communities of these species. The experimental approach was validated in a confirmatory experiment where optimum communities were tested. These results did not differ under a moderate drought treatment. Results were generally consistent between field and greenhouse studies. Western wheatgrass (WWG) had the highest overall plant density and the strongest effect on the forage yield of the mixtures and communities. In the field study, productivity and crude protein content were not reduced when other species were also included with WWG in the mixture. Dalea spp. did not establish as well as the other species, but had the highest crude protein concentrations. The strongest predictors of productivity were the presence and abundance of perennial C3 grasses. Increases in species richness, functional group richness, and the presence of C3s (more specifically western wheatgrass) also increased productivity, likely because of the high early relative growth rate and strong competitive ability of western wheatgrass. Overall, communities screened in the greenhouse reflected early establishment field results. The systematic approach for evaluating communities can be modified to consider enhancing other ecological functions in addition to high productivity, in other regions.
150

The application of remote sensing, GIS, geostatistics, and ecological modeling in rangelands assessment and improvement

Hosseini, Seyed Zeynalabedin 06 August 2013 (has links)
No description available.

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