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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.
41

Evaluating a Negotiated Rulemaking Process at Cape Hatteras National Seashore: Toward Piping Plover and People in One Place

Merritt, Lavell 2009 December 1900 (has links)
Local communities, individuals, visitors, and special interest groups are often called upon to participate in the decision making processes of the National Park Service (NPS). Cape Hatteras National Seashore (CAHA) engaged in a Negotiated Rulemaking process to create an Off Road Vehicle Management Rule. The rulemaking process involved park stakeholders working with the NPS as a Negotiated Rulemaking Advisory Committee with the goal of creating an Off Road Vehicle Management Rule for CAHA. This dissertation used Senecah's practical theory Trinity of Voice to evaluate CAHA's negotiated rulemaking process. Interviews with park staff and negotiated rulemaking participants provided information about the presence of the grammars of TOV in this decision making process. This dissertation described the affects of negotiated rulemaking on the perceptions of participants towards the park resources and management of the national seashore. The effect of the negotiated rulemaking process was an increase in the knowledge of participants about the decision making process employed by the NPS. In general, participants also developed a stronger relationship with park management. This research suggests critical dimensions for achieving widespread social legitimacy through meaningful public involvement in decision making.
42

Life on the edge : morphological and behavioral adaptations for survival on wave-swept shores /

Miller, Luke Paul. January 2008 (has links) (PDF)
Thesis (Ph. D.)--Stanford University, 2008. / Submitted to the Department of Biology. Copyright by the author. Includes bibliographical references (p. 183-205). Also available online.
43

An intertidal survey of Cape d'Aguilar, Hong Kong with special reference to the ecology of high-zoned rock pools

Cheung, Pui-shan, Catherine., 張佩珊. January 1991 (has links)
published_or_final_version / Zoology / Master / Master of Philosophy
44

Predicting shoreline response to wave and sea level trends.

Corbella, Stefano. 31 October 2013 (has links)
In March 2007 the KwaZulu-Natal coastline was devastated by an extreme storm event. There is international concern that such events are associated with climate change. There is evidence of global changes in climate but there is still uncertainty as to whether they are anthropogenic or part of natural decadal (or longer) cycles. The increase in frequency and intensity of extreme storm events will impact on the sediment dynamics of coastlines and the associated risks need to be modelled and quantifed so that they can be included in coastal planning and management. Durban is a coastal city on the east coast of South Africa and has been used as a case study to identify trends in wave parameters and beach profile volumes. The correlation between profile erosion, waves and tides was explored using singular spectral analysis. The dependence between wave parameters was modelled using copulas. The decadal trends were introduced into these models using a nonstationary generalised extreme value distribution. Numerical models (SWAN, SBEACH, XBEACH) were used to transform the statistical model to near shore waves and estimate the associated erosion. The copula model was used to investigate the relationship between multivariate return periods and erosion return periods. Coastal defence options were reviewed and those appropriate for Durban were identifed. This study provides a review of Durban and Richards Bay's 18 years of Waverider data. It presents wave parameter exceedance statistics and wave height return periods for Durban. Durban's wave data showed increasing trends in maximum significant wave heights, peak wave period, storm event frequencies and a trend towards a more southerly mean wave direction. However, only the increase in peak period and wave direction was statistically significant. The trend in wave direction is considered a potential coastal hazard as it has the potential to increase the littoral drift by 1 % per annum. Durban's beach profiles have shown a long term erosion trend which is due to a combination of wave and sea level trends, and a reduction in sediment supply. The reduction in sediment supply from rivers was found to be both anthropogenic and natural. Storm, wave parameter and sea level trends were estimated to contribute more than 75 % to the total long term erosion. It was found that it takes an average of 2 years for a beach to recover to its pre-storm volume. Different types of coastlines recover at different rates and these recovery rates should be considered in risk assessments. A method for estimating future impacts due to storm and sea level trends has been proposed in the form of a non-stationary copula based statistical model. In general a bivariate return period of wave height and duration was found to approximate erosion return periods, while a method for estimating an analogous multivariate storm and erosion return period was developed. Geotextile sand filled containers were found to be a suitable coastal defence as they satisfy social, environmental and political pressure. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2012.
45

Patterns and effects of disturbance in Caribbean macrophyte communities

Tewfik, Alexander January 2004 (has links)
This thesis examines a number of natural and anthropogenic disturbances within marine macrophyte habitats of the Caribbean. Understanding the effects of disturbance and the patterns associated with such dynamics is fundamental to ecological studies. Dynamics of interest included: interactions between populations; interactions between life history strategies; successional regimes; and alterations of community structure including loss of trophic heterogeneity and the possibility of "alternate" states. First I explored natural physical disturbance and succession. The dominance of macroalgae in the mid-shore, between areas of seagrass, challenged "classic" succession in such communities. I therefore proposed a model that included chronic "stress" by wave energy that could lead to a reversal in the climax state. Next, I investigated the importance of other grazers (i.e. trophic heterogeneity) in mediating the strength of trophic cascades (e.g. overgrazing). The enclosure experiments used suggested that different life history strategies respond differently to experimental conditions and that interference competition between specialist (conch) and generalist (urchins) grazers results in urchins switching to alternate resources and displaying lower condition. This dynamic may indirectly "buffer" the community against population expansions of urchins and overgrazing of diversity enhancing detritus. Under high nutrient enrichment, urchins maintained themselves, the trophic cascade and low diversity by switching to "expanded" autochthonous and "new" allochthonous resources. I continued to examine the effects of increasing nutrient enrichment, which correlated well with increasing human density, by examining eleven seagrass beds. The patterns of increasing consumer density and decreasing consumer diversity corresponded well to increasing enrichment and loss of autochthonous detritus. At high levels of enrichment, the community was dominated (> 90%) b
46

Swash zone sediment suspension and transport

Puleo, Jack A. 14 July 1998 (has links)
Graduation date: 1999
47

The functional biology of Porphyra sp. in New Zealand

Schweikert, Katja, n/a January 2007 (has links)
The intertidal red algal genus Porphyra is found on rocky shores worldwide. In the Northern Hemisphere the genus is well studied but there is a paucity of data on southern hemisphere Porphyra and even less on New Zealand Porphyra. The species� taxonomy has been undergoing revision since the late 1990�s, when it was discovered that the main species P. columbina and P. lilliputana reported for New Zealand were a combination of several endemic species. These species are found from the low to the high intertidal watermark; hence they are exposed to fluctuating stresses such as desiccation, temperature, high light and UV radiation. Algae have evolved a number of mechanisms to adapt to naturally changing increasing abiotic conditions, such as accumulation of screening pigments and changes in antioxidant metabolism during light stress. For terrestrial plants, polyamines (small aliphatic amines) have been shown to be involved in protecting cells from damage under conditions of stress including UV-B radiation; such mechanisms have yet to be identified in algae. The overall aim of this study was to determine the importance of cellular processes in shaping the community structure of Porphyra on a wave-exposed shore on the east coast of the South Island, New Zealand. Porphyra distribution and community structure was assessed by regular monthly monitoring of presence and absence of Porphyra along four transect lines at the site. Enviromnental information was recorded to determine the effects of temperature, light, UV radiation, humidity and wind on Porphyra�s spatial and temporal distribution. Regular tissue samples were taken for species identification by the application of primers, which were specifically designed during this study. P. cinnamomea and Porphyra spec. "ROS 54" were identified as dominant species present almost throughout the year with a pronounced maximum in presence during late winter and spring, and some weeks of absence during April or May. The two dominant species were recorded from the low to the high intertidal shore, but the mid intertidal was identified as the preferred habitat. Other species that were found were rare and only present for a few months in a very restricted area. It was hypothesised that free radical generation and antioxidant metabolism are associated with desiccation tolerance in Porphyra. An attempt was made to investigate the impact of desiccation stress on Porphyra. The extraction process of antioxidants was problematic and no reproducible results could be obtained. It was attempted to investigate the spatial distribution of spores and conchocelis of different Porphyra species in the field, and determine if those found at Brighton Beach are species-specific in their morphology. This indicated that the two main Porphyra species at Brighton Beach not only prefer to occupy the same habitat but that they also have a morphologically similar conchocelis phase. Mechanisms on a cellular level such as polyamine metabolism affected by environmental (abiotic) stresses are related to the alga�s ability to adapt to stress and therefore can have an effect on Porphyra�s distribution along the shore and its presence throughout the year. The depletion of the ozone layer has become an important issue as the effects of increased UV radiation on the environment, especially the intertidal habitat, are revealed. Marine macrophytes possess the main three. polyamines: putrescine, spermidine and spermine of varying levels. For the few species studied, Rhodophyta generally contain higher levels of polyamines than Chlorophyta, while polyamine levels for the one heterokontophyte analysed were between Chlorophyta and Rhodophyta. Levels of the three most common polyamines (putrescine, spermidine, spermine) were determined in P. cinnamomea under controlled UV exposure. Tissue discs were exposed to visible light (PAR), PAR and UV-A or PAR, UV-A and UV-B radiation. Discs exposed to PAR and PAR and UV-A showed little change in polyamine levels over a six day trial period, while discs exposed to PAR, UV-A and UV-B showed a significant increase in free, bound soluble and bound insoluble polyamines over the same period of time. Correspondingly levels of ADC and ODC, two enzymes involved in polyamine synthesis, were measured. ODC levels changed little while ADC levels increased significantly during UV-B treatment, indicating that under UV-B stress polyamines are mainly synthesized via the ADC pathway. The experimental set-up and process of this study has not been applied in macroalgal polyamine research and results obtained are the first indication that increased levels of polyamines are involved in protection and/or protection mechanisms in macrophytic algae to prevent UV-B damage.
48

Estudo populacional de Stramonita haemastoma (Gastropoda, Prosobranchia) / A population study of Stramonita haemastoma (Gastropoda, Prosobranchia))

Udelsmann, Bruno 02 November 2009 (has links)
Orientadores: Vera Nisaka Solferini, Sonia Cristina da Silva Andrade / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-14T00:32:41Z (GMT). No. of bitstreams: 1 Udelsmann_Bruno_M.pdf: 3710944 bytes, checksum: d180c3d886961b5fcad87d1976916dd3 (MD5) Previous issue date: 2009 / Resumo: Neste estudo foram analisados por eletroforese de isoenzimas e morfometria tradicional, indivíduos de Stramonita haemastoma, uma espécie de gastrópode que habita costões rochosos no litoral brasileiro. Foram feitas coletas em nove localidades no litoral dos estados de Santa Catarina, São Paulo e Rio de Janeiro. Em estudo prévio com esta espécie havia sido encontrado um distinção genética em dois grupos. Tal distinção se manteve, com diferenças marcantes nas freqüências dos alelos de três locos. Assim sendo, após interpretação dos géis de isoenzimas as amostras foram sub-divididas em dois grupos, denominados A e B. E esta divisão foi corroborada por um teste de atribuição de genótipos utilizando o programa Structure. Os grupos genéticos foram então tratados independentemente para a obtenção de estimativas de variabilidade e estruturação genéticas. Os valores encontrados foram similares aos de outros moluscos com desenvolvimento larval planctotrófico. Sendo encontrada variabilidade moderadamente alta e estruturação reduzida. O grupo B apresentou maior estruturação indicando possíveis diferenças entre os grupos quanto ao desenvolvimento e dispersão. Foram encontrados poucos desvios significativos do equilíbrio de Hardy-Weinberg foram poucos, assim como de desequilíbrio de ligação. Diversos locos apresentaram diferenças significativas de freqüência entre os grupos A e B. A distância genética média das amostras foi de 0,338 entre os grupos, 0,006 entre as amostras do grupo A e 0,015 entre as amostras do grupo B. Estes valores são comparáveis aos encontrados em espécies cogenéricas. Nos mesmos indivíduos das análises genéticas foram tomadas oito medidas distintas para análise morfológica. As medidas foram analisadas separadamente e por análise de componentes principais. A maior parte da diversidade foi encontrada entre as localidades amostradas e não entre os grupos A e B. Nossos resultados indicam que S. haemastoma possui uma complexidade taxonômica ainda não elucidada, tendo os grupos A e B características de espécies crípticas. / Abstract: In this study, Stramonita haemastoma individuals, a gastropod who inhabits marine rocky shores, were analysed through isozymes electrophoresys and traditional morphometrics. Nine localities in the brazilian shore, extending from Santa Catarina to Rio de Janeiro were sampled. In a preliminary study, a genetic distinction in two different groups was detected. This distinction continues to be found, with evident differentiation in three loci and in minor degree in other loci. After the interpretation of the isozymes data, individuals were adressed as belonging to groups A or B according to their genotypes. To corroborate with this division a genotype atribution test was performed using the software Structure, which resulted in a division 92% similar. The groups A and B were treated independently to obtain the genetic variability and structure parameters. Values were similar to other molluscs whith similar larval development, with moderately high variation and reduced population structure. Group B has higher population structure indicating possible differences in development or dispersal. There were few deviations to Hardy-Weinberg and few linkage disequilibrium, many loci differed in frequencies between populations of distinct groups. Genetic distance was in average 0,338 between populations of distinct genetic groups, a value comparable to other cogeneric species. Between group A populations the distance was in average 0,006 and between group B populations distance was of 0,015 in average. The same individual from the genetic analysis were used for the morphometrics. Eight different shell measures were used. Data was analysed measure by measure and through principal components analysis. The majority of variation was found between sample sites rather than between the groups A and B. From the results of this study it is possible to affirm that the taxonomy of S. haemastoma is not fully understood. The groups A and B have typical characteristics of cogeneric sibling species. More studies are necessary, in broader areas to asses the groups the status of distinct species, by the moment S. haemastoma should be adressed as a species complex. / Mestrado / Genetica Animal e Evolução / Mestre em Genética e Biologia Molecular
49

Bertioga: paisagem, ambiente e urbanização / Bertioga: landscape, environment and urbanization

Roberto Sakamoto Rezende de Souza 02 June 2008 (has links)
O presente trabalho analisa o processo de transformação da paisagem litorânea paulista a partir da segunda metade do século XX, utilizando como estudo de caso o município de Bertioga. Este se configura como um município florestal, que ainda em 2008 tem preservada a integridade das dinâmicas ecológicas de seus ecossistemas costeiros, que sobreviveram ao intenso processo de expansão urbana por que passaram muitos municípios vizinhos. Dificuldades históricas de acesso, e a entrada em vigor a partir de meados da década de 1980 de um conjunto de instrumentos jurídicos que impuseram severas restrições à supressão de vegetação nativa de Mata Atlântica, permitiram que em Bertioga fossem observados padrões de ocupação urbanos diferenciados dos observados em grande parte da Baixada Santista, onde a malha urbana substituiu completamente a vegetação primitiva das planícies litorâneas. A urbanização com fins turísticos, o loteamento e a residência de veraneio, são entendidos como os principais vetores de desestruturação das dinâmicas ecológicas presentes na paisagem natural do litoral paulista. Neste cenário o ecossistema de restinga se encontra em posição de especial vulnerabilidade, pois possui formações específicas que somente se desenvolvem nos terrenos firmes de orla marítima, preferidos para a ocupação turística. / The purpose of this dissertation is to analyze the ways in which São Paulos shore landscape has changed throughout the years since the fifties, through a case-study: the city of Bertioga. Bertioga is defined by landscape architecture researchers as a forest municipality, which, in the year of 2008, still has most of its coastal ecosystems ecologic dynamics preserved, in spite of the rapid process of urban growth that most of the nearby cities went through. The factors responsible for this strinking difference in Bertiogas development from other cities in the same area where the urban tissue has completely replaced the original vegetation are mainly the access to the city, traditionally difficult, and the implementation, since the Eighties, of a number of effective laws that have imposed severe restrictions concerning the destruction of Mata Atlânticas (brazilian coastal rainforest) native vegetation. The urban occupation with tourist purposes, the criteria for the division of land into plots and the increasing construction of vacation homes are seen as the main reasons for dismantling the structures of the ecologic dynamics existent in the natural landscape of São Paulos shoreline. Under these circumstances, the restinga ecosystem is specially vulnerable, due to certain formations that occur solely on firm ground along the shoreline the tourists favourite spots.
50

Conservation genetics and phylogeography of endangered boreoarctic seashore plant species

Kreivi, M. (Marjut) 20 January 2009 (has links)
Abstract The amount and distribution of genetic diversity are likely to affect the evolutionary potential of a species. When feasible and cost-effective policies for management and monitoring of endangered populations or species are planned, knowledge of the spatial genetic structure and the type of population dynamics is of great concern. In this thesis the genetic diversity and population structures of two endangered arctic plant species was examined on different geographical scales in Northern Europe. The species were Siberian primrose (Primula nutans) and pendant grass (Arctophila fulva), which both grow in a seashore habitat and have similar distribution patterns on the shores of the Arctic Ocean and the Bothnian Bay. The goal of the present study was to provide basic population genetic information for the study species using microsatellite and AFLP markers. Both markers were used for the first time in these species, and species-specific microsatellite markers were developed during the study. A further aim was to interlink the population genetic processes of the species into distribution patterns at the regional and population levels and to compile a synthesis of the impact of hierarchical spatiotemporal processes and autocorrelation in genetic variation at different levels. The studies of this thesis provided new information on the diversity and population structure of the endangered study species and new markers that are useful in future genetic studies of primrose species. The diversity of Siberian primrose was low, and there was no dispersal between the study regions. In pendant grass, a relatively high amount of variation was found considering the evident clonal reproduction and gene flow that was detected between populations connected by waterways. The results suggested that both clonal and sexual reproduction are important in this species. On a local scale, pendant grass populations had characteristics of “stepping stone” and classical metapopulation models. The results indicated that on a long time scale, both species will continue to decline without efficient management efforts. Most critical for the persistence of the species is the conservation of suitable habitats. Translocations could be considered in order to enhance the diversity of existing populations and establish new populations. By examining the present day structure of Siberian primrose, it was possible to make inferences regarding the colonisation history of the species in the North European area. The current distribution of Siberian primrose seemed to result from a vicariant process that took place after the last ice-age, when the species colonised the area. It spread first to the White Sea area, probably from the east, and subsequently colonised the Bothnian Bay and the Barents Sea in the west. The isostatic land uplift after the retreat of the Eurasian ice sheet uncovered large areas of land from the Baltic Sea basin that previously were under water. These geological changes resulted in the current disjunct distribution of Siberian primrose.

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