Spelling suggestions: "subject:"1species"" "subject:"3species""
711 |
Golden-cheeked warbler nest predators and factors affecting nest predation /Stake, Mike M. January 2003 (has links)
Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references. Also available on the Internet.
|
712 |
Golden-cheeked warbler nest predators and factors affecting nest predationStake, Mike M. January 2003 (has links)
Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references. Also available on the Internet.
|
713 |
The winter ecology of piping plovers (Charadrius melodus) along the Texas Gulf CoastZonick, Curtis A. January 2000 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 162-168). Also available on the Internet.
|
714 |
A comprehensive methodology for measuring costs and benefits of critical habitat designation under the Endangered Species ActSlack, John Taylor. January 2003 (has links) (PDF)
Thesis (M. S.)--Public Policy, Georgia Institute of Technology, 2004. / Norton, Bryan, Committee Chair; Noonan, Douglas, Committee Member; Kirkman, Robert, Committee Member. Includes bibliography.
|
715 |
Physiological and Behavioral Mechanisms of Range Expansion in the House Sparrow (Passer domesticus)Liebl, Andrea Lyn 01 January 2013 (has links)
Introduced species cause both considerable ecological and economic damage every year. However, not much is known about how certain species are able to establish and spread beyond the site of initial introduction, whereas others do not. Species undergoing range expansion following an introduction may prove to be a valuable resource to invasion biology, but may also be informative in light of species' responses to changing environments (i.e. global climate change). Here, I took advantage of an ongoing range expansion of an introduced vertebrate species. House sparrows (Passer domesticus) were introduced to Mombasa, Kenya in the 1950s and have subsequently expanded their range northwest-ward and now occupy most major cities in Kenya. By comparing older, established populations (i.e. those in Mombasa) with more recently colonized populations at the range edge, it might be possible to determine some of the mechanisms that underlie range expansion in some species and/or populations. In Chapter 1, the background and ideas that motivated the rest of the dissertation is summarized. In Chapter 2, I studied how exploration and glucocorticoids (a hormone released in response to stressors) changed throughout the range expansion. Exploration was greater at the range edge, which is likely to ensure greater discovery of novel resources. Glucocorticoids released in response to restraint were also highest at the range edge, which might facilitate resolution of stressors in unpredictable environments. However, chronically elevated levels of glucocorticoids are often considered maladaptive, unless an individual can appropriately cope with them. Therefore, in Chapter 3, I characterized glucocorticoid receptors (i.e. mineralocorticoid receptor (MR) and glucocorticoid receptor (GR)) in the hippocampus, an area responsible for negative feedback of glucocorticoids as well as induction of behavioral and physiological response to stressors. I found that MR density was lower relative to GR density at the range edge compared to the site of introduction (Mombasa). I speculate this pattern is a mechanism to resolve the elevated levels of glucocorticoids at the range edge. Taken together, these results indicate that individuals at the range edge have a strong glucocorticoid response to stressors to induce a rapid, strong response to resolve stressors. Subsequently, in Chapter 4, I examined the potential mechanisms of phenotypic change among Kenyan house sparrows. Typically, following an introduction event, genetic diversity undergoes a bottleneck and is greatly reduced compared to the source population; as such, genetic evolution as the main driver of changing phenotypes throughout the range expansion is unlikely. We therefore hypothesized that epigenetic mechanisms (e.g. DNA methylation) may compensate for the expected reduced genetic diversity following an introduction. Although there was no pattern of epigenetic variation among cities (i.e. variation did not increase nor decrease further from the site of introduction), epigenetic variation increased as genetic inbreeding increased (a sign of reduced genetic diversity and bottlenecks), suggesting epigenetic modifications may compensate for reduced genetic diversity following an introduction event. Overall, patterns of phenotypic variation emerged dependent on age of the population- these patterns may prove to be important in other vertebrate range expansions as well. Surprisingly, epigenetic diversity did not correlate with phenotypic variation among populations; however, within-individual studies may reveal epigenotypes are related to certain behavioral or physiological phenotypes. In the future, studies should be designed to address how phenotypic differences arise despite relatively low genetic diversity and overall high genetic admixture among individuals. In Kenyan house sparrows, maintenance of high levels of flexibility and differential developmental influences may be important factors that lead to varying phenotypes dependent on time since colonization.
|
716 |
Social perceptions of nonhumans in Tombali (Guinea-Bissau, West Africa) : a contribution to chimpanzee (Pan troglodytes verus) conservationCosta, Susana Gonçalves January 2010 (has links)
Rainforest biodiversity is particularly vulnerable to loss, since the distribution of forests is limited and the vertebrate species that live within these forests have a limited potential to re-colonize deforested areas, especially when their abundance declines to critical levels. Guinea-Bissau (West Africa) is experiencing significant loss of habitats and species diversity; as such, the establishment of an effective conservation programme is urgent in its remaining forested areas. Despite six legislated protected areas, Guinean forests and their wildlife are not safe in reality. This lack of on-the-ground protection is the case for Cantanhez National Park (Tombali region), where this research took place. The park was established in 2007 to protect remnant forests containing unique and endemic Guinean biodiversity, such as the endangered West African chimpanzees (Pan troglodytes verus). Local inhabitant’s attitudes towards protected areas and associated externallydriven conservation programmes are seldom examined in depth in relation to understanding the drivers (livelihood, socio-cultural, and local) of perceptions, which makes conservation problematic. Understanding attitudes to animals, habitats and livelihood risks were the focus of this project, specifically in order to assess perceptions of chimpanzees. Chimpanzees are currently suffering catastrophic declines due to human actions across Africa. Thus a focus on understanding, managing and enhancing people’s perceptions and attitudes towards this species could be vital to its long-term survival. The theoretical approach is based upon (i) examining the construct of sociozoologic scales in this specific socio-cultural context, (ii) elucidating issues in humanwildlife interaction (e.g. conflict such as crop-raiding and positive such as ecotourism potential), (iii) local economies (i.e. level of dependency on forest resources), and (iv) understanding people’s expectations about the future of the National Park as a potential constraint or opportunity for their welfare and livelihoods. Quantitative and qualitative methods were combined to approach these questions. 17 The Guinean sociozoologic scale of Cantanhez clearly divides vertebrate species into (i) “tame”, considered good (e.g. gazelles) and (ii) “hazardous”, considered bad (e.g. hyaenas). Chimpanzees lay exactly in the midpoint. They are considered humans’ close relatives; however, they “misbehave” as astute crop thieves sufficiently to be perceived as a competitor for resources. Since chimpanzees are also seen as very similar to humans, their meat consumption is taboo, which adds the potential for protection. Gender and religion both influence the way locals perceive of and relate to chimpanzees. Women and Muslims tend to be more negative towards this species and the protected area than are men and non-Muslims. Women never exhibited positive attitudes in relation to the protected area, while men appeared to be more engaged with “capitalized” principles, with some awareness about the importance chimpanzees might have in catalyzing the National Park and local economy. This study highlights the need for a management plan to mitigate crop-raiding and the development of sustainable strategies that provide livelihood benefits for both men and women, addressing their distinct needs, outside the protected area.
|
717 |
Restoration and management of wildflower-rich machair for the conservation of bumblebeesRedpath, Nicola January 2010 (has links)
Over the last half century, the widespread decline of bumblebees across the agricultural landscapes of Western Europe and North America has been well documented. This decline has undoubtedly been driven to a large extent by the intensification of agriculture, which has fragmented landscapes and removed large areas of suitable foraging habitat, nesting and hibernation sites. Consequently, some of the rarest Bombus species now persist only in isolated pockets of semi-natural habitat, which have been subjected to little agricultural intensification. Of the 25 Bombus species native to the UK, three species have gone extinct in recent decades and several others are severely threatened. Remaining populations of the UK’s rarest bumblebee, Bombus distinguendus, have become strongly associated with florally-rich machair grassland habitats found only in the North and West of Scotland and Western Ireland. Machair, a unique habitat that forms on soils rich in shell sand, has been maintained by rotational agricultural practices implemented by crofters. However, recent changes in crofting practices, which include the intensive grazing of machair in some areas, or conversely the abandonment of machair management all together in others, have resulted in sections of machair that have become degraded and consequently exhibit low floral abundance and species diversity. This has significant implications for species such as B. distinguendus, which have for the most part come to rely of the florally-rich swards of machair grassland. This thesis aimed to develop a greater understanding of how machair grassland habitats are utilised by foraging bumblebees, including B. distinguendus, and in turn examined the potential for restoring degraded areas of machair via a variety of methods. The research presented here examines the influence of current crofting practices on the abundance of bumblebees and their forage plant species and combines this information with a detailed exploration of the machair seed bank and potential machair restoration treatments. The specific foraging requirements of B. distinguendus were found to be similar to those of other long-tongued bumblebee species and the provision of plants from the Fabaceae family was found to be of particular importance. Current crofting practices implemented in the North and West of Scotland were, on the whole, found support low numbers of foraging bumblebees. Similarly, existing habitat management schemes, designed to provide early cover for corncrakes and foraging resources for bumblebees, were found to be largely ineffective in attracting B. distinguendus, when compared with florally-rich machair habitat. In addition, this research suggests that the existing machair seed bank is unlikely to provide a sufficient resource for reinstating florally-rich habitat to degraded areas of machair. However, this thesis has demonstrated that it is possible to implement seed mixes on machair which can reinstate species typical of machair plant communities and which also attract high numbers of foraging bumblebees. The findings of these habitat assessments and restoration trials are examined in full in the following chapters and implications for the future management of wildflower-rich machair are discussed throughout.
|
718 |
Population trends, conservation and the trade in amphibians in AsiaWhite, Steve January 2005 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
|
719 |
Studies in materials chemistry : the preparation of surface-oriented multilayered assembliesSpells, Darrell Jackson 12 February 2015 (has links)
This text describes the synthesis of surface-oriented multilayers based on novel monomeric species. The impetus of this study is to incorporate atypical species and techniques in order to prepare well-ordered assemblies on gold surfaces. These thin films were characterized by one or more of following techniques: grazing angle FT-IR; optical ellipsometry and x-ray photoelectron spectroscopy. First, chemical vapor deposition polymerization was used to prepare surface-oriented monolayers on amine functionalized gold from 4-aminobenzaldehyde and 5-phenyl-1, 3-dioxolane-2, 4-dione. The 4-aminobenzaldehyde showed regular increases in the intensity of characteristic IR absorptions with number of deposition cycles while the dioxolane showed no regularity in this respect. We infer from our data that this technique is a practical way to synthesize highly conjugated polymers. Secondly, we investigated the preparation of surface oriented materials based on host-guest assemblies. Cyclodextrin functionalized gold surfaces could serve as orientational templates for multilayered well-ordered host-guest materials. However, in our study, thiol modified cyclodextrin showed no ability to organize surface multilayers via surface crystallization in the presence of the appropriate host; nor did it show an ability to pre-organize in solution via polyethylene glycol rotaxane formation followed by surface attachment. Finally, surface-oriented organometallic monolayers and multilayers were prepared from alkyne functionalized gold surfaces. Using bis-orthodimethylaminomethyl (NCN) ligands we synthesized two unique surface-oriented organometallic assemblies. Palladium NCN hydrosulfides formed monolayers on gold. Characterization by FT-IR, XPS and ellipsometry show that these species similar to their thiol counterparts. In addition, organometallic polymers were grown from alkyne functionalized surfaces. The thickness of these films, which reached 40 Å by ellipsometry was dependent upon the nature of the alkyne initiator. / text
|
720 |
The horny toad man : a battle against time and looming public apathy to save Texas’ most iconic reptileDropkin, Alexander Joseph 24 February 2015 (has links)
Bill Brooks is worried about the future of his organization, perhaps even more than he is about the future of horned lizards. Brooks is the president and a founding member of the Horned Lizard Conservation Society, a nonprofit with the goal of protecting all species of horned lizard. The HLCS was founded in Austin in 1991, after its members realized that populations of Texas horned lizards, Phrynosoma cornutum, had crashed at some point in the preceding decades; they wanted to both figure out what had happened to the lizards and how to bring them back. Cornutum is an iconic species and the state reptile, and almost all Texans over the age of 40 can remember seeing them in the hundreds as children. Flash-forward a quarter of a century, and a lot of these founding members are either old and grey or deceased. HLCS membership is down, and Brooks thinks that if there aren’t any of his kind left (Texans that grew up with “horny toads”), there’ll be no one left to care. Herpetologists are working on returning healthy horned lizard populations to the wild, and both reintroduction and relocation programs are showing signs of success. But can they work, and will it be too late for Brooks’ organization and a Texas identity dependent upon horned lizards? / text
|
Page generated in 0.0428 seconds