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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.
261

The effects of elevation, tree cover, and fire on ant populations in a pinyon-juniper dominated watershed

MontBlanc, Eugénie M. January 2005 (has links)
Thesis (M.S.)--University of Nevada, Reno, 2005. / "May 2005." Includes bibliographical references (leaves 26-29). Online version available on the World Wide Web.
262

Conservation of the spotted turtle (Clemmys guttata) identifying critical demographic and environmental constraints affecting viability /

Harms, Hillary M. January 2008 (has links)
Thesis (Ph.D.)--Bowling Green State University, 2008. / Document formatted into pages; contains xi, 99 p. : maps. Includes bibliographical references.
263

Vegetation dynamics and tree radial growth response in harvest gaps, natural gaps, and closed canopy conditions in maine's acadian forest /

Schofield, Darci A., January 2003 (has links) (PDF)
Thesis (M.S.) in Forestry--University of Maine, 2003. / Includes vita. Includes bibliographical references (leaves 132-138).
264

Conservation of Crop Wild Relative Species in Bolivia An Outline to Identify Favorable and Unfavorable Factors to Support a Conservation Program

January 2011 (has links)
abstract: Since the Convention on Biological Diversity was established in 1992, more importance has been given to the conservation of genetic resources in the international community. In 2001, the International Treaty on Plant Genetic Resources for Food and Agriculture (PGRFA) focused on conserving plant genetic resources, including crop wild relatives (CWR). Some of these genetic resources hold desirable traits--such as transfer of plant disease resistance, improvement of nutritional content, or increased resistance to climate change--that can improve commercial crops. For many years, ex situex situ conservation was the prevalent form of protecting plant genetic resources. However, after PGRFA was published in 1998, in situ techniques have increasingly been applied to conserve wild relatives and enhance domesticated crops.In situ techniques are preferred when possible, since they allow for continued evolution of traits through natural selection, and viability of seed stock through continuous germination and regeneration. In my research, I identified regions in Bolivia and rated them according to their potential for successful programs of iin situ conservation of wild crop relatives. In particular, I analyzed areas according to the following criteria: a) The prevalence of CWRs. b) The impacts of climate change, land use change, population growth, and economic development on the continued viability of CWRs in an area. c) The socio-political and economic conditions that might impede or facilitate successful conservation programs and outcomes. This work focuses on three genera of particular importance in Bolivia: Peanut (Arachis spp.), Potato (Solanum spp.) and Quinoa (Chenopodium spp.). I analyzed the above factors for each municipality in Bolivia (the smallest scale for which appropriate data were available). The results indicate which municipalities are most likely to successfully engage in CWR conservation projects. Finally, I present guidelines for the creation of conservation projects that pinpoint some of the potential risks and difficulties with in situ conservation programs in Bolivia and more generally. / Dissertation/Thesis / M.S. Biology 2011
265

Reconciling conservation and development in Madagascar's rapidly-expanding protected area system

Gardner, Charlie J. January 2014 (has links)
The creation and management of protected areas is our principal approach to conserving biodiversity worldwide. Management and governance models for these diverse institutions have become more pluralistic in recent decades, moving away from the traditional exclusionary protected area model that has proliferated historically. Indeed, most new protected areas are being established for ‘multiple-use’ and, therefore, permit a range of human livelihood activities to occur within their boundaries. However, we know little about how such sites can be effectively managed. In this thesis, I use an interdisciplinary mixed-methods approach to investigate the implementation of new multiple-use protected areas in Madagascar. Madagascar is a global conservation priority characterised by high levels of endemism, and has a largely forest-dependent biota. Since most of the human population is rural and dependent on natural resources for subsistence and income to differing extents, the expanded protected area system is managed for both conservation and socioeconomic goals (poverty alleviation and development). However, these objectives may be conflicting since human resource use can be a significant driver of biodiversity loss. I begin by examining trends in new protected area establishment at the nationwide-level to generate insights into protected area categorisation, and the role of natural resources and protected areas in poverty alleviation. I then consider the impacts of forest use on biodiversity, through a literature review and empirical study of bird and reptile communities across a degradation gradient. The findings indicate that habitat change arising from forest use may impact the high-value, endemic component of the fauna most negatively. In addition, I develop a simple index to enumerate the conservation value of different species. This is then used to determine how degradation influences the conservation value of exploited habitats, as well as assessing if the index is a suitable tool that can be used to prioritise conservation investment across a portfolio of sites. Finally, I seek to understand the drivers of natural resource use by rural communities within the Ranobe PK32 protected area, and discover that both bushmeat hunting and charcoal production are fallback activities or supplements to other livelihoods. The evidence collated in the thesis, derived from both ecological and social perspectives, suggests that managing new protected areas in Madagascar for conservation and development is overambitious, and that, at least in forest areas, management cannot be optimised towards both goals simultaneously.
266

Entendendo o viés de detecção nos atropelamentos de fauna : avaliação de método, variação entre os observadores e atributos das carcaças

Pinheiro, Paula Fabiana January 2016 (has links)
A detecção é um fator que afeta a magnitude estimada de fauna atropelada, informação relevante nos estudos e trabalhos de biologia da conservação. Em rodovias, a estimativa da detecção é afetada por diferentes elementos, como os tipos de pavimento; os atributos das carcaças; as particularidades dos diferentes observadores e o método utilizado para aferição. Nosso trabalho avalia essas questões, especifica o esforço amostral e corrige a estimativa de fauna atropelada em relação à detecção. Encontramos diferença na estimativa de detecção entre os diferentes pavimentos; entre as carcaças similares e contrastantes ao substrato; entre os diferentes observadores e verificamos que através do monitoramento a pé não se detecta a totalidade das carcaças. Esses resultados e a estimativa de fauna atropelada corrigida comprovam a importância da aferição da detecção antes e depois da pavimentação das rodovias, através de método experimental. Sendo que o experimento deve contemplar a implantação de diferentes carcaças e ser realizado pelas equipes que participaram dos monitoramentos de fauna. / Detection is a factor that affects the estimated magnitude of the roadkill and is relevant information in biological conservation studies. In roads, the detection estimation is affected by many factors, such as type of paving, the carcasses traits, the particularities of different observers and the method used for measurement. Our study evaluates these questions, specify the sample effort and correct the roadkill magnitude in relation to detection. We found differences in the estimation of detection between the different kinds of paving, between carcasses similar to the paving and between those contrasting to the substrate. We also found differences between different observers and thus monitoring by walking does not detect all carcasses. These results and the roadkill magnitude corrected demonstrate the importance of the standardization of the detection before and after the paving of roads, via experimental methods. However, the experiment should include the implementation of different substrates and should be carried out by the teams that have already participated in the monitoring of fauna.
267

Conservation ecology of the endangered freshwater pearl mussel, Margaritifera margaritifera

Thomas, Gethin Rhys January 2011 (has links)
The general aim of this thesis was to examine the merits of ex-situ vs. in-situ strategies for the conservation of the endangered freshwater pearl mussel, Margaritifera margaritifera, and to investigate the relationship of the larval parasitic stages of the mussel (glochidia) with the salmonid hosts. To this end, I critically reviewed the literature on conservation of freshwater mussels, developed methods for quantifying the behaviour and activity patterns of adult mussels in captivity, experimentally studied host specificity, and quantified the physiological and behavioural effects of glochidia upon salmonid hosts. The results indicate that the conservation of the freshwater pearl mussel is probably best addressed at the watershed scale, and will benefit from a combination of ex-situ and in-situ techniques, as well as from a more critical assessment of findings, many of which are only reported in the grey literature. Empirical, peer-reviewed data are badly needed to inform current conservation efforts. Novel Hall-effect magnetic sensors were used to quantify and characterise discrete mussel behaviours without adversely affecting the welfare or survival of adult mussels, and these hold considerable potential for determining optimal rearing conditions for ex-situ conservation. Arctic charr was shown to be a potentially suitable host for M. margaritifera, and occupied an intermediate position in host suitability between brown trout and Atlantic salmon. Physiological impacts of glochidia upon brown trout included swelling of secondary lamellae and spleen enlargement, but the latter tended to be slight and was restricted to 1 month post-exposure. Glochidia encystment had no significant effect on blood haematocrit, respiratory performance, or cryptic colouration of brown trout hosts. The behavioural effects were more subtle and glochidiosis made brown trout more risk-averse and less willing to explore a novel habitat, without affecting the host's ability to chemically recognise and avoid cues from a predator. Overall, the results of this thesis indicate that the impacts of glochidia upon salmonid hosts are probably slight and temporally variable, and may perhaps lead to increased host survival, which would support the symbiosis-protocooperation theory of glochidia-salmonid interaction.
268

Entendendo o viés de detecção nos atropelamentos de fauna : avaliação de método, variação entre os observadores e atributos das carcaças

Pinheiro, Paula Fabiana January 2016 (has links)
A detecção é um fator que afeta a magnitude estimada de fauna atropelada, informação relevante nos estudos e trabalhos de biologia da conservação. Em rodovias, a estimativa da detecção é afetada por diferentes elementos, como os tipos de pavimento; os atributos das carcaças; as particularidades dos diferentes observadores e o método utilizado para aferição. Nosso trabalho avalia essas questões, especifica o esforço amostral e corrige a estimativa de fauna atropelada em relação à detecção. Encontramos diferença na estimativa de detecção entre os diferentes pavimentos; entre as carcaças similares e contrastantes ao substrato; entre os diferentes observadores e verificamos que através do monitoramento a pé não se detecta a totalidade das carcaças. Esses resultados e a estimativa de fauna atropelada corrigida comprovam a importância da aferição da detecção antes e depois da pavimentação das rodovias, através de método experimental. Sendo que o experimento deve contemplar a implantação de diferentes carcaças e ser realizado pelas equipes que participaram dos monitoramentos de fauna. / Detection is a factor that affects the estimated magnitude of the roadkill and is relevant information in biological conservation studies. In roads, the detection estimation is affected by many factors, such as type of paving, the carcasses traits, the particularities of different observers and the method used for measurement. Our study evaluates these questions, specify the sample effort and correct the roadkill magnitude in relation to detection. We found differences in the estimation of detection between the different kinds of paving, between carcasses similar to the paving and between those contrasting to the substrate. We also found differences between different observers and thus monitoring by walking does not detect all carcasses. These results and the roadkill magnitude corrected demonstrate the importance of the standardization of the detection before and after the paving of roads, via experimental methods. However, the experiment should include the implementation of different substrates and should be carried out by the teams that have already participated in the monitoring of fauna.
269

The effects of herbivory, competition, and disturbance on island meadows

Gonzales, Emily Kristianne 05 1900 (has links)
It is an unresolved paradox that non-native species are successful in novel environments whereas native species, presumably adapted to that environment, decline. This knowledge gap has persisted because third party processes in invasion ecology have been overlooked. Ungulate densities are increasing due to the eradication of predators and landscape change and I asked how herbivory and invasion might interact to cause declines of native species. In Garry oak meadows, Canada’s most endangered ecosystem, native forbs have declined relative to non-native grasses and I tested the facilitatory role of herbivory in that degradation. My investigations, novel to the field, were conducted on islands spanning the Canada-US border. Islands served as natural experimental units in a mensurative study of abundance patterns in seven plant groups and 15 focal species along gradients of herbivory, biogeography, soil depth, and human activities. Increasing ungulate densities were related to declines in abundances of native forbs, and increasing abundances of non-native annual grasses. These regional patterns were upheld by two plot-based, 2x2 factorial experiments that contrasted the fitness of native species under manipulations of herbivory and competition for light. Specifically, I showed that ungulates limited the establishment, growth, survival and reproduction of seedlings and transplanted native forbs and shrubs and that competition from non-native species had little effect. I also calculated forage selectivity indices and tested the efficacy of fencing and cutting to reduce competition, for the restoration of native community biomass. Non-native annual grasses were rarely browsed and increased with increasing ungulate density. Non-native perennial grasses declined with herbivory, however, their regional abundances were unaffected by ungulate density despite being preferentially foraged. That non-native annual and perennial grasses differed in their responses to herbivory has consequences for restoration and illustrates the challenge of developing a comprehensive theory of invasion. Reducing ungulates, necessary for the recovery of native forbs, also benefits non-native perennial grasses and therefore their removal speed recovery of Garry oak meadows. Despite advances in invasion ecology, scientists and managers are disconnected and research is rarely implemented. I conclude by proposing seven solutions to facilitate the integration of science into management. / Forestry, Faculty of / Graduate
270

Examining the Impacts of Ecotourism on Humpback Whales (Megaptera novaeangliae) in Panama

January 2020 (has links)
abstract: Cetacean-based ecotourism is a popular activity and an important source of revenue for many countries. Whale watching, a subset of cetacean-based ecotourism, is vital to supporting conservation efforts and provides numerous benefits to local communities including educational opportunities and job creation. However, the sustainability of whale-based ecotourism depends on the behavior and health of whale populations and is therefore vital that ecotourism industries consider the impact their activities have on whale reproductive behavior. To address this statement, behavioral data (e.g. direction change, breaching, slap behaviors, diving, and spy hops) were collected from humpback whales (Megaptera novaeangliae) in Las Perlas Archipelago off the Pacific coast of Panama to determine if vessel presence had an influence on whale behaviors. Studies were recorded during their breeding season from August through September in 2019. Based on 47 behavioral observations, higher boat density corresponded with humpback whales changing direction which is believed to be a sign of disturbance. This result is important given Panamanian regulations implemented on February 13 of 2007 prohibit whale-based tourism from disturbing whales, which is measured as changes in behavior. Because there is no systematic monitoring of whale watching activity to enforce the regulations, there is currently little compliance among tour operators. The integration of animal behavior research into management planning will result in more effective regulation and compliance of conservation policies. / Dissertation/Thesis / Masters Thesis Biology 2020

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