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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.
61

Factors affecting the dynamics and regulation of coral-reef fish populations

Webster, Michael Scott 11 September 2001 (has links)
Ecologists have long questioned why fluctuating populations tend to persist rather than go extinct. Populations that persist indefinitely are regulated by mechanisms that cause demographic density dependence, which works to bound fluctuation above zero. In a series of studies, I have sought to determine the processes and mechanisms that regulate local populations of coral-reef fish. In the Exuma Keys, Bahamas, fairy basslets (Gramma loreto) live in aggregations on the undersides of coral-reef ledges. These aggregations often constitute local populations because movement between aggregations is rare. The largest individuals occupy prime feeding positions near the front of ledges and force smaller individuals remain near the back where they have lower feeding rates. Based on these initial observations, I designed two experimental studies of the demographic consequences of variation in basslet density. In the first study, I manipulated the density of newly-settled fish to explore the effects of high recruitment on population size. Populations with experimentally elevated recruitment converged in density with unmanipulated populations, primarily due to density-dependent mortality. I found no evidence that density dependence was caused by intraspecific competition; rather it appeared to be due to a short-term behavioral response by predators (aggregative and/or type 3 functional response). In a second study, I manipulated the densities of adults among populations with a standard average density of newly-settled fish. Two measures indicated that the intensity of competition increased at higher densities of adults, which likely made small fish more susceptible to predation, thereby causing density-dependent mortality. Long-term observations indicated that basslet populations were regulated at temporal scales exceeding two generations. At Lizard Island on the Great Barrier Reef, I also examined how patterns of recruitment of coral-reef fishes were modified across a range of natural recruit densities in the presence and absence of resident predators. Predators decreased recruitment and increased mortality for all species, but these effects varied considerably among species. The results of each of these studies stress the importance of both competitive and predatory mechanisms in modifying patterns of abundance established at the time of larval settlement, as well as regulating local population size. / Graduation date: 2002
62

Site Fidelity Assessment of Atlantic Bottlenose Dolphins (Tursiops truncatus) Following Large-Scale Emigration of Sympatric Atlantic Spotted Dolphins (Stenella frontalis) in the Bahamas

Unknown Date (has links)
Two sympatric species of dolphins (Atlantic spotted dolphins, Stenella frontalis and Atlantic bottlenose dolphins, Tursiops truncatus) have been long-term residents to Little Bahama Bank. This study assessed whether there was a change in residence patterns or diurnal foraging depths of bottlenose dolphins following a large emigration event in the resident spotted dolphin community on this sandbank. Photo-identification was used to identify individual bottlenose dolphins and compare pooled years before (2010-2012) and after (2013-2015) the spotted dolphin emigration. The identified community size and overall residency of the bottlenose dolphins remained similar, although two bottlenose dolphins emigrated over deep water to the site spotted dolphins emigrated. Bottlenose dolphins diurnally fed in shallower water but remained in the same geographic foraging locations. Reasons remain unknown for this depth change, but potential changes in the productivity of primary bottlenose dolphin foraging habitats or reduction of spotted dolphins from shallower depths remain possibilities. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection
63

An Empirical Assessment of Factors Contributing to Individuals' Propensity to Commit Software Piracy in The Bahamas

Wells, Raymond Cleophas 01 January 2012 (has links)
Researchers have found that software piracy worldwide over the years has significantly contributed to billions of dollars in lost revenue for many software firms. Software developers have found it difficult to create software that is not easily copied, thus, creating a software protection problem. Software piracy remains a global problem despite the significant effort to combat its prevalence. Over the years, significant research has attempted to determine the factors that contribute to individuals' propensity to commit software piracy. Most of the research on software piracy has been limited to larger societies, with recommendations by researchers to extend similar studies to smaller ones. The literature indicating the need for additional research on this topic in different populations and cultures is significant. Given that, the key contributions of this study were to assess empirically factors such as personal moral obligation (PMO), cultural dimensions, ethical computer self-efficacy (ECSE) and the effect it has on individuals' propensity -- in cultures that support it -- to commit software piracy in smaller geographical locations. Therefore, this research empirically assessed the contribution that PMO, Hofstede's cultural dimension of individualism/collectivism (I/C), and ECSE have made on individuals' propensity to commit software piracy. The study extended the current body of knowledge by finding answers to three specific questions. First, this study sought to determine whether the PMO component contributed to individuals' propensity to commit software piracy in The Bahamas. Secondly, this study sought to determine the level of contribution of Hofstede's cultural dimension of I/C to individuals' propensity to commit software piracy in The Bahamas. Finally, this study sought to determine the contribution of ECSE to individuals' propensity to commit software piracy in The Bahamas. A total of 321 usable responses were collected over a one-month period from students from the school of business at a small Bahamian college, to determine their level of PMO, I/C, and ECSE contribution to individuals' propensity to commit software piracy. This represents, approximately, a 64% response rate. The results showed the overall significance of the models of the three factors in predicting individuals' propensity to commit software piracy. Furthermore, the results indicated that PMO and ECSE subscale PMO and ECSE_DB were significant, however, I/C, and ECSE (as a whole) were not.
64

Elasmobranch longline capture : ecological application, physiological impacts and alternative techniques

Brooks, Edward James January 2013 (has links)
Longline fishing is the most common elasmobranch capture method in the world, both for commercial fishing, and to a lesser extent for scientific surveys. The capture of an animal on a longline initiates a series of physiological responses designed to promote survivorship in the short term, but if unchecked, can cause reduced individual fitness and/or mortality in the long term. Given widespread declines in shark populations, an improved understanding of the physiological costs of longline capture is needed. The aim of this thesis was to investigate the physiological response of sharks to capture and restraint, to assess novel, non-invasive alternatives to scientific longline surveys, and to generate scientific insight into poorly understood elasmobranch populations in The Bahamas. The results presented herein suggest that some species of shark are able to recover from the physiological stress of capture despite the presence of persistent negative stimuli. Tonic immobility was assessed as a means of generating baseline blood chemistry data, but was found to be inappropriate given that it increases the magnitude of physiological perturbation in the short term. To avoid the stress of capture altogether, Baited Remote Underwater Video Surveys (BRUVS) were considered as a non-invasive alternative to capture based surveys, however, it was concluded that they lack the resolution necessary to answer fine scale demographic questions. For the Caribbean reef shark, longline surveys yielded high resolution data allowing the identification of fine scale spatiotemporal shifts in demographic population structure with minimal cost (mortality). Nevertheless, the ethics of using capture based surveys on sensitive species are questionable when alternative techniques are available. Deep water sharks caught on longline surveys exhibited high mortality rates, however, for these very poorly understood species moribund specimens have great scientific value which in some cases can offset the high ecological costs of the surveys. The results presented in this thesis highlight the on-going need for improved biological and ecological research into the majority of elasmobranch populations, particularly with regards to anthropogenic interactions such as capture. Given the tenuous conservation status of many species, the acquisition of applied, management focused data should remain the priority of elasmobranch scientists.
65

Novel Bacterial Diversity in an Anchialine Blue Hole on Abaco Island, Bahamas

Gonzalez, Brett Christopher 2010 December 1900 (has links)
Anchialine blue holes found in the interior of the Bahama Islands have distinct fresh and salt water layers, with vertical mixing, and dysoxic to anoxic conditions below the halocline. Scientific cave diving exploration and microbiological investigations of Cherokee Road Extension Blue Hole on Abaco Island have provided detailed information about the water chemistry of the vertically stratified water column. Hydrologic parameters measured suggest that circulation of seawater is occurring deep within the platform. Dense microbial assemblages which occurred as mats on the cave walls below the halocline were investigated through construction of 16S rRNA clone libraries, finding representatives across several bacterial lineages including Chlorobium and OP8. In many blue holes, microbial metabolism of organic matter in the presence of seawater sulfate leads to anoxic and sulfidic conditions at or below halocline. Sunlight penetrating this sulfidic layer allows for in situ primary production to be dominated by bacterial anoxygenic phototrophs. Although water column chemistry and molecular genetic diversity of microbial mats in Cherokee Road Extension Blue Hole were investigated in this study, the full scope of the biogeochemistry of inland blue holes throughout the Bahamas Archipelago is complex and poorly understood. However, these microbial communities are clearly influenced by several factors including solar insolation, terrestrial and marine inputs of oxygen, carbon, and nutrients, water residence times, depth to the halo/chemocline, and cave passage geometry. The biogeochemistry of inland blue holes throughout the Bahamas is so distinctive which makes Abaco Island and the rest of the archipelago valuable as natural experiments, repositories of microbial diversity, and analogs for stratified and sulfidic oceans present early in Earth's history.
66

Resilience at Risk: Epistemological and Social Construction Barriers to Risk Communication

Stoffle, Richard W., Minnis, Jessica 01 January 2008 (has links)
This paper is about the persistent failure of social scientists to bring into the Environmental Impact Assessment (EIA) process socially constructed environmental concerns held by potentially impacted communities. The failure to communicate perceived risks results from a two-communities divide based on both epistemological differences and obfuscation due to vernacular communication. The analysis provides robust modeling variables that can bridge this social-environmental divide. The case involves data collected from members of traditional communities regarding their perceptions of the potential impacts of proposed Marine Protected Areas (MPAs). The study is situated in the Bahamas where the government has approved setting aside 30 No-take MPAs to protect their sea. This analysis is based on 572 interviews conducted during eight field trips with members of six traditional settlements in the Exuma Islands and Cays in the central Bahamas. Confidence in the findings is high because the sample involves 34% of the census population of these settlements and the findings have repeatedly been returned for review and approval by the members of these settlements.
67

At the Sea’s Edge: Elders and Children in the Littorals of Barbados and the Bahamas

Stoffle, Brent W., Stoffle, Richard W. 27 January 2007 (has links)
Littorals in the in the Exuma Cays, Bahamas and the Bath Plantation, Barbados are comparative in many ways. These edges of the sea have provided critical services to local people during the time of slavery and since. More than food and medicine, the littoral is the nightly sea bath, where children are instructed, and the last ecosystem effectively used by the elderly. Independence and self- respect derive from use and protection of these littoral by individuals and communities. Local patterns of conservation and use are argued to be essential in the ecological structure and functions of the littoral. Development projects and marine protected areas alike are seen as potentially breaking local ties with the littoral causing trophic skew and damaging local society. If development occurs, mitigation solutions potentially derive from legally recognizing local people as partners in the co-management of their traditional littoral. Included with this article is a presentation prepared by Drs. Brent and Richard Stoffle.
68

Environmental Multiplicity in the Bahamas: Situating Traditional Ecological Knowledge and Conservation Ethics in Cultural Landscapes

O'Meara, Nathaniel, B. 05 1900 (has links)
Based on ethnographic research conducted in the Exumas Cays, Bahamas, this thesis investigates how traditional ecological knowledge (TEK) and conservation ethics are situated in place and integrated into cultural landscapes. This is illustrated using satellite imagery and ethnographic data to describe the TEK associated with kitchen gardens, plant-collecting areas, fishing grounds, farm fields and pastures within the traditional use areas of one Exumian settlement known as The Hermitage. By situating TEK in cultural landscapes, this thesis provides a more holistic representation of the interconnectedness between community, knowledge, practice, belief, place, and landscape. This thesis also includes discussions on the theoretical importance of linking TEK with place and landscape; the formation and role of conservation ethics in preserving places or resources in a local environment; and a description of an emerging theory in cultural ecology called environmental multiplicity, which argues for the resiliency of traditional social-ecological systems as a result of creating multiple subsistence strategies and webs of interdependent social relationships to guard against social and natural perturbations.
69

Harbour Island: The Comparative Archaeology of a Maritime Community

Hatch, Heather E 16 December 2013 (has links)
Archaeological research at Harbour Island, Bahamas, was designed to help explore and develop the concept of maritimity, or identity grounded in perceived (or imagined) shared traits deriving from a community’s relationship with the maritime environment. Maritimity can best be identified by using three broad and overlapping categories of Landscape, Maritime Resources and Maritime Material Culture. Historical documents and maritime cultural landscape elements establish the maritimity of Harbour Island in the context of these categories. Artifacts, procured through archaeological survey of nine properties inhabited since at least the eighteenth century, are analyzed to investigate whether there any notable differences in the archaeological assemblages of maritime communities that indicate maritimity. Analysis relies on Stanley South's artifact classification system and his Carolina Artifact pattern. The nine properties are compared among themselves as well as with four other sites from the western British Atlantic region. Comparisons between the Harbour Island sites reveal a strong homogeneity of ceramic types at all households and a low representation of personal and clothing artifacts that indicate the relative poverty of the community. Maritime activities are not strongly represented in the archaeological record. When compared to four other sites from Jamaica, South Carolina, North Carolina, and Delaware, the assemblage from the Harbour Island community is relatively comparable to other sites influenced by British colonial culture. Although the domestic artifacts contain little maritime material culture, the development of the island's built environment demonstrates maritimity in both the categories of Landscape and Maritime Material Culture. Faunal remains from Harbour Island, consisting primarily of fish and shellfish, provide archaeological evidence of the importance of the Maritime Resources category. Only when the evidence from all three categories of maritimity is considered together can Harbour Island be identified archaeologically as a community that strongly identified with both the maritime environment and the dominant British Colonial Atlantic culture.
70

The Crinoid Genus Endoxocrinus in the Bahamas: an Assessment of Morphological Variability.

Bellew, Patrick H. 17 December 2008 (has links)
The morphology of members of the isocrinid genus, Endoxocrinus, found by A.H. Clark, 1908, in the Bahamas was examined to see if current classification schemes are valid. Individuals included in this survey belonged to the current species Endoxocrinus prionodes, Endoxocrinus carolinae, and Endoxocrinus parrae. Additionally, individuals of two depth-related morphotypes of E. parrae were examined. Evidence is presented that suggests that E. carolinae should be included in E. parrae, while the validity of E. prionodes is maintained. No evidence was found to warrant the recognition of the two depth-related morphotypes as distinct. Rather, these forms, as well as traditional E. parrae and E. carolinae, encompassed a high degree of variability along a morphological continuum. The study concludes that a revision of the genus should be considered and that isocrinid species can be much more variable in morphology than was previously recognized.

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