Spelling suggestions: "subject:"lagoa."" "subject:"lagar.""
11 |
Frontiers of urban survival : everyday corruption and precarious existence in LagosAgbiboa, Daniel Egiegba January 2016 (has links)
The vast corpus of works on corruption in Africa focuses almost exclusively on 'grand corruption' and political elites (so-called 'Big Men'), and hardly on 'everyday corruption' and ordinary actors. When everyday corruption appears in the literature, it is frequently explained away as petty and/or normal - something expected and accepted. In this study, I take issue with this predominant narrative, couched in an equally dominant but narrow Weberian notion of corruption. Grounding corruption in the micro-politics of urban public transport in Lagos, Nigeria's commercial capital and Africa's largest city, I argue that ordinary actors detest the corruption that they encounter daily. At the same time, their power(lessness) in the face of its banality compels them to constantly devise tactics to find a way around it or to make it productive for their ends. Structured into six chapters, the study begins by probing the popular imagination, discourse, and spatiality of corruption. It then shows how corruption is embedded in routine socio-economic relations, how it conditions ordinary lives and social livelihoods, and how everyday actors encounter it, exploit it, resist it, or become its victims each day. The study required eight months of ethnographic fieldwork grounded on the routine experiences and lifeworlds of road transport workers in Lagos, Nigeria. My direct experience of the 'surrounds' of these urban actors, the 'junctions' that constitute the spatial hinge of violent extortion and complicity, and routine participation in the omnipresent 'danfos' (commercial minibus-taxis) enabled access to a sense of how this complex system works.
|
12 |
Vozes de Lagos: brasileiros em tempos do Império Britânico / Lagos voices: Brazilians in the age of the British EmpireSilva, Angela Fileno da 25 April 2016 (has links)
A ideia de que os brasileiros estabelecidos em Lagos elaboraram identidades cambiantes que se reformularam em resposta aos contextos apresentados ao longo do período de 1840 a 1900, constituiu o foco central desta tese. Neste sentido, proponho compreender os contextos em que os brasileiros de Lagos tiveram de ressignificar e atualizar os signos responsáveis por conferir identificação aos integrantes de seu grupo. Para isto, selecionei um conjunto de documentos formado por três tipos de fontes. Com o propósito de entender como os brasileiros eram representados por missionários anglicanos e metodistas, exploradores, oficiais da marinha e cônsules britânicos analisei as narrativas de viagem, relatórios enviados ao Foreign Office e artigos publicados em revistas mantidas por associações científicas da época. O segundo grupo de documentos corresponde a três jornais publicados em Lagos entre os anos de 1881 e 1900, a saber: The Lagos Observer, The Lagos Weekly Record e o periódico oficial do governo colonial britânico, The Government Gazette. A leitura destas fontes revelou aspectos importantes acerca da participação dos brasileiros na sociedade lagosiana da segunda metade do século XIX. O terceiro compêndio de fontes é formado por relatórios anuais elaborados pela administração colonial da cidade e reunidos sob a denominação de Blue Books. Este conjunto de registros trata dos mais diferentes assuntos relacionados ao governo britânico operado na cidade e constitui importante fonte para análise acerca da maneira como os brasileiros eram representados pelo governo colonial. A partir destes três conjuntos de documentos tornou-se possível perceber as formas como os signos de pertencimento que definiam as identidades dos brasileiros foram elaborados a partir do contato, das trocas e das disputas entre os demais componentes sociais existentes na cidade de Lagos oitocentista. / The Brazilians established in Lagos developed shifting identities which were reshaped in response to the presented contexts throughout the period 1840 to 1900, was the central focus of this thesis. In this regard, I propose to understand the contexts in which the Brazilian from Lagos had to reframe and update the responsible signs for checking identification to the members of their group. For this, I selected a set of documents composed of three types of sources. In order to understand how Brazilians were represented by Anglican and Methodist missionaries, explorers, officers of the Navy and British consuls, I analyzed the travel narratives, reports to the Foreign Office and articles published in magazines kept by scientific associations at the time. The second group of documents corresponds to three newspapers published in Lagos between the years 1881 and 1900, namely: The Lagos Observer, The Lagos Weekly Record and the official journal of the British colonial government, The Government Gazette. Reading these sources revealed important aspects concerning the Brazilian participation in Lagos society in the second half of the nineteenth century. The third compendium of sources consists of annual reports by the colonial administration of the city and gathered under the name of Blue Books. This set of records focus on the most different topics related to the British government based in the city and is an important source of analysis about the way the Brazilians were represented by the colonial government. From these three sets of documents it was possible to see the ways in which the belonging signs which defined the identity of Brazilians were prepared from the contact, exchanges and disputes between the other social components existing in the Lagos of the nineteenth century.
|
13 |
Vozes de Lagos: brasileiros em tempos do Império Britânico / Lagos voices: Brazilians in the age of the British EmpireAngela Fileno da Silva 25 April 2016 (has links)
A ideia de que os brasileiros estabelecidos em Lagos elaboraram identidades cambiantes que se reformularam em resposta aos contextos apresentados ao longo do período de 1840 a 1900, constituiu o foco central desta tese. Neste sentido, proponho compreender os contextos em que os brasileiros de Lagos tiveram de ressignificar e atualizar os signos responsáveis por conferir identificação aos integrantes de seu grupo. Para isto, selecionei um conjunto de documentos formado por três tipos de fontes. Com o propósito de entender como os brasileiros eram representados por missionários anglicanos e metodistas, exploradores, oficiais da marinha e cônsules britânicos analisei as narrativas de viagem, relatórios enviados ao Foreign Office e artigos publicados em revistas mantidas por associações científicas da época. O segundo grupo de documentos corresponde a três jornais publicados em Lagos entre os anos de 1881 e 1900, a saber: The Lagos Observer, The Lagos Weekly Record e o periódico oficial do governo colonial britânico, The Government Gazette. A leitura destas fontes revelou aspectos importantes acerca da participação dos brasileiros na sociedade lagosiana da segunda metade do século XIX. O terceiro compêndio de fontes é formado por relatórios anuais elaborados pela administração colonial da cidade e reunidos sob a denominação de Blue Books. Este conjunto de registros trata dos mais diferentes assuntos relacionados ao governo britânico operado na cidade e constitui importante fonte para análise acerca da maneira como os brasileiros eram representados pelo governo colonial. A partir destes três conjuntos de documentos tornou-se possível perceber as formas como os signos de pertencimento que definiam as identidades dos brasileiros foram elaborados a partir do contato, das trocas e das disputas entre os demais componentes sociais existentes na cidade de Lagos oitocentista. / The Brazilians established in Lagos developed shifting identities which were reshaped in response to the presented contexts throughout the period 1840 to 1900, was the central focus of this thesis. In this regard, I propose to understand the contexts in which the Brazilian from Lagos had to reframe and update the responsible signs for checking identification to the members of their group. For this, I selected a set of documents composed of three types of sources. In order to understand how Brazilians were represented by Anglican and Methodist missionaries, explorers, officers of the Navy and British consuls, I analyzed the travel narratives, reports to the Foreign Office and articles published in magazines kept by scientific associations at the time. The second group of documents corresponds to three newspapers published in Lagos between the years 1881 and 1900, namely: The Lagos Observer, The Lagos Weekly Record and the official journal of the British colonial government, The Government Gazette. Reading these sources revealed important aspects concerning the Brazilian participation in Lagos society in the second half of the nineteenth century. The third compendium of sources consists of annual reports by the colonial administration of the city and gathered under the name of Blue Books. This set of records focus on the most different topics related to the British government based in the city and is an important source of analysis about the way the Brazilians were represented by the colonial government. From these three sets of documents it was possible to see the ways in which the belonging signs which defined the identity of Brazilians were prepared from the contact, exchanges and disputes between the other social components existing in the Lagos of the nineteenth century.
|
14 |
Morphodynamics in the Lagos Lagoon : observation and inferences of changeAlademomi, Alfred Sunday January 2017 (has links)
The focus of this research is the study of lagoon ecosystem interaction and adjustment of the lagoon floor morphologies, water dynamics and sequences of change involving the motion of sediment. The aim of the study is to implement a functional mechanism to evaluate and analyse changes in the Lagos Lagoon and its ecosystem, with the objectives: (i) to investigate the extent and impact of urban expansion on the Lagoon coastline and its ecosystem; (ii) to quantify changes in the spatial extent of mangroves by use of satellite images from 1984 to 2016; (iii) to investigate the spatial dynamics of the Lagoon water floor and estimate its flushing time, (iv) to investigate the behaviour and relationship pattern of the Lagoon hydrodynamic parameters;, (v) to collect sediment samples from the Lagoon, analyse their settling behaviour and particle size distribution (PSD) in order to study their spatial evolution and characterisation; and (vi) to initiate a model that can predict the influence of sea level rise on the Lagoon ecosystem. The existing problem of an overcrowded human population in Lagos, the incessant repository of industrial effluence into its Lagoon, and increased flooding from the immediate watershed generate the research questions for this thesis. Lack of studies in the areas of morphodynamics and hydrodynamics on the Lagoon is a gap in the body of coastal knowledge, especially the temporal and long term dynamics of a significant Lagoon like that of Lagos. Understanding the dynamics of the Lagoon will enhance efficient monitoring, sustainable management and hence reveal the great importance the Lagoon preserves for the coastal region. Landsat images (1984 – 2016) of the study area (Lagos Lagoon) and its ecosystem were obtained for some specific data derivations. Land Surface Temperature (LST), NDVI and delineated Lagoon coastline were derived from the images. An Environment for Visualizing Images (ENVI) and a Geographic Information System (GIS) were used to extract land classification information, likewise, the GIS was used to develop a model for investigating the Lagoon coastline changes. With the use of ENVI and GIS software, land classification types were derived with the percentage of the coverage area for each land use classification for the years of study. A novel empirical method was designed to collect in-situ hydrodynamic data for both the dry and wet seasons in 2014, this was correlated and analysed using a case study approach. Also, in-situ bathymetric data was collected in 2014 to join the 2008 available data for studying the changes in the Lagoon water bed morphology. Functional models were used to examine the interaction of the various hydrodynamic information that was studied on the Lagoon. Results and inferences from the study show that the wetland of the system is depleting rapidly with increase urbanisation. In both lateral and vertical directions, the morphological shape of the Lagoon is reducing both in size and depth. The result from the model that investigated the system coastline indicates that reclamation and recession are taking place on the Lagoon coast at an approximate ratio of 4 to 1 whereas, the total surface area has reduced to approximately 204.51km2 as opposed to its approximate area of 208km2 as at the year 2010. The results from the analysis of the Lagoon salinity implies a wide salinity variation between the dry and the wet season; this confirms the system as brackish water in the dry season and freshwater in the wet season. Other inferences reveal the critical point of well-mixed water mass, significant vertical mixing during the wet season and a stable state during the dry season. In overview, the ratio of the Lagoon stratification during the dry season to that of the wet season is approximately 1 to 7 and flushing time of approximately 26 days and 22 days respectively. Lastly, the Lagoon possesses a varying settling velocity that is uniquely related to the diameter of its particles at various spatial locations. This research has been able to provide baseline investigations concerning the morphology and hydrodynamic study of the Lagos Lagoon.
|
15 |
A relação dos fatores abióticos e da densidade de Cylindrospermopsis raciborskii (Cyanophyceae) na concentração de cianotoxinas e estruturação da comunidade zooplanctônica em uma lagoa costeira subtropicalBrentano, Débora Monteiro January 2016 (has links)
Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas, Programa de Pós-Graduação em Ecologia, Florianópolis, 2016. / Made available in DSpace on 2017-07-11T04:22:45Z (GMT). No. of bitstreams: 1
346423.pdf: 1867472 bytes, checksum: 8d404e9189422c9606a63881b5fd9d32 (MD5)
Previous issue date: 2016 / As relações entre variáveis abióticas, densidade de Cylindrospermopsis raciborskii e concentração de cianotoxinas foram estabelecidas em um lago costeiro subtropical (Lagoa do Peri - Florianópolis/SC - Brasil). O efeito da variação da concentração de toxinas no ambiente natural e a variação da densidade de C. raciborskii sobre população do zooplâncton (Cladocera) foi testado "in vitro"; e, investigou-se potenciais variáveis preditoras de cianotoxinas para este manancial que abastece 100 mil habitantes. Foram coletadas mensalmente amostras de água da Lagoa do Peri (Julho/2013 a Setembro/2014) e analisadas a composição do fitoplâncton, cianotoxinas dissolvidas e intracelulares e variáveis limnológicas. Oito grupos de cianotoxinas (microcistinas, nodularina, microginina, cyanopeptolinas, anabaenopeptinas, anatoxinas, cilindrospermopsina e saxitoxina) foram analisados usando cromatografia líquida associada à espectrometria de massa ionizante (MS/MS). Essas mesmas amostras foram testadas para toxicidade utilizando Daphnia magna. A relação entre a concentração de STX e as variáveis físicas, nutrientes e clorofila-a foi analisada utilizando um conjunto de dados de 45 meses de monitoramento (Março/2007 a Agosto/2014). A comunidade fitoplantônica foi dominada por cianobactérias (97,4% indivíduos por volume), composta por C. raciborskii (55,6%; 1,0 a 3,8 x 104 ind.mL-1) e Limnothrix sp. (41,8%; 0,7 a 3,6 x 104 ind.mL-1), ambas abundantes durante todo o período de estudo. Altas temperaturas e nutrientes (ortofosfato, nitrogênio inorgânico dissolvido (NID) e nitrogênio total) favoreceram a densidade de C. raciborskii. Apenas STX foi encontrada na Lagoa do Peri em baixa concentração (0,013±0,007 µg.L-1) e intracelularmente. A densidade de C. raciborskii teve relação significativa positiva com a concentração de STX na Lagoa do Peri, mas o poder explicativo é de apenas 20% sugerindo não ser um preditor robusto da concentração da toxina no sistema. Já as variáveis abióticas condutividade elétrica e a concentração de NID apresentaram maior poder explanatório (49%) na variação da concentração de STX "in situ". Testes de toxicidade aguda podem ser potencialmente utilizados em triagem preliminar de STX no ambiente natural. Foi observada uma boa correlação linear (84%) entre a concentração de STX no ambiente e o efeito no zooplâncton em testes ?in vitro?. A toxicidade aguda observada para o zooplâncton é melhor explicada pela variação da concentração de STX (amostra bruta ? relação marginalmente significante, p= 0,09, pseudo - R2 = 0,18; e amostra sonicada ? relação significante, p<0,05, pseudo - R2 = 0,16) que pela densidade de C. raciborskii (relação não significante, p>0,05, pseudo - R2 = 0,012). O efeito de intoxicação aguda devido a ingestão de C. raciborskii contendo STX é uma característica definitiva na estruturação da comunidade do zooplâncton, uma vez que seleciona o zooplâncton capaz de coexistir com esta cianobactéria no ecossistema. O mecanismo em que variáveis abióticas regulam a variação da concentração de STXs intracelular em C. raciborskii e a consequente intoxicação aguda do zooplâncton por herbivoria sugere uma estruturação do tipo "bottom-up" para este ambiente.<br> / Abstract : The cyanobacterium Cylindrospermopsis raciborskii produces toxins including saxitoxins (STXs). The main aim was to understand the relation among abiotic variables, cyanotoxin concentration and C. raciborskii density. These relations are very important to manage reservoirs and understand aquatic community structure, but have been few explored in situ. We tested the effect of toxin concentration and C. raciborskii density of natural water samples on a zooplankton population (Cladocera) in vitro. In addition, we investigated some abiotic variables as potential predictors of cyanotoxin concentration in the Peri Coastal Lake (Santa Catarina Island, Brazil). This lake has been historically dominated by C. raciborskii and supplies potable water for about 100,000 local citizens. Water samples was collected monthly between July 2013 and September 2014 being analyzed for phytoplankton composition, intracellular and dissolved cyanotoxins, and limnological variables. A suite of eight cyanotoxin groups (microcystins, nodularin, microginin, cyanopeptolins, anabaenopeptins, anatoxins, cylindrospermopsin, and saxitoxin) was targeted using liquid chromatography tandem (MS/MS) mass spectrometry with electrospray ionization. These samples were also used in ecotoxicological tests using Daphna magna. The relationship among STX concentration and physical variables, nutrients and chlorophyll-a (chl-a) was analyzed using a dataset of 45-month monitoring period (March/2007 to August/2014). The phytoplankton community was dominated by cyanobacteria (97.4% individual per volume), comprised of C. raciborskii (55.6%, 1.0 to 3.8 x 104 ind.mL-1) and Limnothrix sp. (41.8%, 0.7 to 3.6 x 104 ind.mL-1), both abundant during the entire study period. High temperatures and nutrients (orthophosphate, dissolved inorganic nitrogen - DIN and total nitrogen - TN) favored the C. raciborskii density. STX was the only cyanotoxin found in the Peri Coastal Lake, in low concentration (0.013±0.007 µg.L-1), and concentrated intracellularly. C. raciborskii density had a significant positive relation with STX concentration, but explained only 20% of the variation in STX concentration. This suggests that C. raciborskii density alone is not a reliable predictor of STX concentrations in this system. However, the abiotic variables as electrical conductivity and DIN concentration provided the greatest explanatory power (49%) for STX concentration in situ. The acute toxicity tests can potentially be used in preliminary screening of STX in the natural environment. We observed a good linear correlation (84%) between STX concentration in the lake with effect on zooplankton in the in vitro tests. The acute toxicity observed on the zooplankton is better explained by the variation in STX concentration (whole water samples - marginal significant relation, p= 0.09, pseudo - R2 = 0.18; and sonicated water samples - significant relation, p<0.05, pseudo - R2 = 0.16) than by the C. raciborskii density (no significant relation, p>0.05, pseudo - R2 = 0.012). The acute intoxication effect of grazing upon STX-containing C. raciborskii is a defining feature in zooplankton community structuration, as this selects for zooplankton that are able to coexist with toxic C. raciborskii in this ecosystem. The abiotic variables have a role on the regulation of intracellularly STX concentration in C. raciborskii and there is acute intoxication in the zooplankton as consequence of the herbivory, so the bottom-up processes seems to drive community structure in Peri Coastal Lake.
|
16 |
Housing delivery systems : an evaluation of public-private partnerships towards provision of adequate housing for the middle-income group in Lagos Nigeria.Alabi, Anthony Sule. January 2012 (has links)
This research thesis examined the applicability of the enablement paradigm in the public-private
partnership (PPP) of housing delivery systems (HDS) in Lagos among middle-income groups
using the periods of changing historic conditions as baseline for the analysis. Nigeria’s postdemocratic
Housing and Urban Development Policy for the first time in 2002 recognized the
formal private sector as a major stakeholder in its framework. This recognition was in line with
the World Bank’s policy recommendation for governments to create enabling environment for
private sector participation in housing provision. The major changes by this policy were the grant
of access to land with ownership tenure and access to housing finance with low interest rate.
This thesis underscores the failure of the Housing and Urban Development Policy framework in
Nigeria to achieve real gains in housing delivery. By unbundling the determinants of HDS in
Lagos, this research identified the universal objectives of housing delivery in terms of the
quantity and quality of housing and its environmental quality.
The findings from this research work identified significant correlation between failures in
government policies and poor stakeholders’ delineation and roles. The study further associated
stakeholder’s delineation and role to PPP optimization: By so, identified PPP as the fulcrum for
resource, process and social optimization towards achieving AHD.
Through an extensive analysis of historic conditions, theories and policies nationally and
internationally, this research drew relevant lessons which informed its conceptual departure for
unbundling PPP within HDS. It also relied on empirical data obtained from quantitative and
qualitative research instruments drawn from four estate typologies and three categorized
stakeholder’s respondents’ frame it used in evaluating HDS.
In its contribution, this study developed a project lifecycle framework for housing development,
a proposal for PPP effectiveness and an Adequacy Evaluation Technique (AET). Common to
these models was the delineation of the universal objectives of housing from which the 3-Qfactor
of housing quantity, and quality and the quality of housing environment emanated as a measure
of value added contribution. By this, the study established a departure from previous
architectural approaches which promised value satisfaction as a functional derivative of design.
Through these models, PPP can be designed at the architectural and operational levels towards
achieving AHD through the window of the universal objective of housing delivery; and can be
evaluated for functional satisfaction and real value (return on investment) based on assessment of
profitability of housing development actors/partners.
The second major contribution is the delineation of stakeholders in three dimensions namely, the
household, the housing development actor/partner which reflects changing roles and
circumstances and the housing development experts. Of emphasis are the changing roles and
circumstances that this study is able to delineate from its literature and field work through an
understanding of the social focus groups which exist within the Lagos settings.
This study in conclusion emphasizes the need for delineating stakeholders’ roles contextually as
a pre-condition to initiating partnerships. It also posits that there is need to deduce all resources,
processes and social context as the framework for PPP before initiating partnerships. It
established that, current policy practice already targets the middle-income in its use of PPP, and
this can be extended to other social income groups and that the basis for the utilization of PPP
should stem from an understanding of specific application of the three-step adequacy evaluation
technique (AET) developed by this study as a relevant tool for evaluating the adequacy of
housing development projects. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2012.
|
17 |
Sexualized nationalism : Lagos and the politics of illicit sexuality in colonial Nigeria, 1918-1958Aderinto, Saheed Adeniyi 21 September 2010 (has links)
In my dissertation, I argue that historians of Africa have overlooked the intersection between nationalism and sexuality, despite the fact that these two themes are related. In addition, instead of focusing on the now stale paradigm which emphasizes the importance of race and class in the discourse of sexuality, I offer a revisionist idea that stresses the importance of age. Hence, I contend that the contrast between underage and adult sexuality largely informed the pattern of reformist condemnation of casual sex work in colonial Lagos. A clash between tradition (crudely defined as African traditional customs, values and ethos) and modernity (the so-called ideals of “modernization” and “civilization” imported by the British colonialists) was inevitable as the reformists vied to establish favorable legislation and combated laws that threatened their belief system and practices. What is more, debates around prostitution went beyond casual sex work to involve more complex matters such as the protection of soldiers, marriage, and cultural nationalism; the place and role of women and children in African society; and African or colonialist conception of morality/immorality. Because of the complex nature of the politics of sex in colonial Nigeria, it was effectively impossible to reach common ground on dealing with the alleged medical and social nuisance caused by prostitutes. Indeed, while the ostensible subject of the popular debate was “prostitution,” the issues contested concurred with cultural nationalism and the protection of individual and group interests. Prostitution became a camouflage for negotiating issues that threatened the social, political, and sexual ideologies and orientation of a wide range of people—Africans and Europeans alike. / text
|
18 |
Migración por amenidad en zonas lacustres de la comuna de Puerto Varas: expectativas asociadas a nuevos modos de vidaJorquera Acuña, Catalina 25 July 2016 (has links)
Magíster en Análisis sistémico Aplicado a la Sociedad. / El estudio parte de la creciente preocupación del mundo científico y desde la opinión pública por los emergentes discursos ambientales, que han generado la consecutiva migración a nivel mundial. Se ha verificado la emergencia de discursos ambientales que sugieren la integración sujeto-naturaleza, que se ven reflejados en distintas posiciones eco-céntricas y en la ocupación de nuevos territorios (zonas rurales), previamente no observados por la sociedad.
Este trabajo, desde una perspectiva cualitativa, y en base al desarrollo de entrevistas semi estructuradas, explora las características de los migrantes por amenidad de la comuna de Puerto Varas. El fin y estructura de esta investigación, se define en pos de dar cuenta de las expectativas previas a la migración; identificar las condiciones de satisfacción y mantenimiento en su actual lugar de residencia; y finalmente, identificar estrategias y mecanismos de inclusión/exclusión, sobre los cuales se generan los nuevos modos de vida. Esto da cuenta de una búsqueda de satisfacción de necesidades emergentes e ilimitadas, en directa relación con el medio natural, surgiendo así las migraciones voluntarias, y más específicamente la migración por amenidad
|
19 |
Efeitos das características de lagos de água preta sobre a ocorrência e a abundância de aves piscívoras no arquipélago de Anavilhanas, rio Negro, Amazônia central, Brasil / Effects of black water lake features on the occurrence and abundance of fish-eating birds in the Anavilhanas Archipelago, Rio Negro, Central Amazonian, BrazilXavier , Renata da Silva 07 August 2015 (has links)
Submitted by Gizele Lima (gizele.lima@inpa.gov.br) on 2016-09-08T21:11:03Z
No. of bitstreams: 2
Dissertação_Renata_Xavier_Versão Final_Biblioteca.pdf: 1421898 bytes, checksum: 57983185c5a53810c99fb8e7ca38a557 (MD5)
license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-09-08T21:11:04Z (GMT). No. of bitstreams: 2
Dissertação_Renata_Xavier_Versão Final_Biblioteca.pdf: 1421898 bytes, checksum: 57983185c5a53810c99fb8e7ca38a557 (MD5)
license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)
Previous issue date: 2015-08-07 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The influence of blackwater lakes characteristics on the occurrence and abundance of 12 fish-eating birds species in the Brazilian Amazon at the population level was evaluated. The central hypothesis was that local variations in lake characteristics should influence the occurrence and abundance of aquatic bird population in a tropical blackwater flooded forest system. An additional hypothesis was tested, the variation in the degree of isolation of the lakes, influence the occurrence and abundance of lake-living waterbirds. Bird surveys were conducted from November to December 2007 in 45 lakes within islands along 100 km of the Anavilhanas Archipelago, Rio Negro, Central Brazilian Amazonia. Multiple linear and multiple logistic statistical models were used to test the effects of nine variables, four physical, two chemical, two geographical, and one biotic, on the occurrence and abundance of 12 species of fish-eating birds. It was found that lake depth and water transparency influenced the occurrance and abundance of Ringed-Kingfisher (Megaceryle torquata) and abundance of Osprey (Pandion haliaetus), Cocoi Heron (Ardea cocoi) and Snowy Egret (Egretta thula). Lake isolation influenced the occurrence of Yellow-billed Tern (Sternula superciliaris) and Striated Heron (Butorides striata), and habitat richness has affected most of the fish-eating birds species. The results indicate that lake limnological and physical attributes are determinants of spatial variation in abundance and occurrence of fish-eating birds in the blackwater lake systems in central Brazilian Amazon. / Foi avaliada, em nível populacional, a influência das características de lagos de água preta sobre a ocorrência e abundância de 12 espécies de aves piscívoras na Amazônia Brasileira. A principal hipótese foi que as variações locais nas características dos lagos deveriam influenciar a ocorrência e abundância de populações de diversas aves aquáticas em um sistema tropical de águas pretas (igapó). Foi testada a hipótese complementar de que as variações no grau de isolamento dos lagos influenciariam a ocorrência e abundância de aves aquáticas nos lagos. Os levantamentos de aves foram conduzidos entre os meses de novembro-dezembro de 2007, em 45 lagos distribuídos em ilhas no Arquipélago de Anavilhanas, ao longo de 100 km no Rio Negro, Amazônia Central, Brasil. Modelos múltiplos lineares e múltiplos logísticos foram utilizados para testar os efeitos de nove variáveis, sendo quatro físicas, duas químicas, duas geográficas e uma biótica, sobre a ocorrência e abundância de doze espécies de aves piscívoras. Foi encontrado que a profundidade do lago e a transparência da água influenciaram a ocorrência e abundância do martim-pescador-grande (Megaceryle torquata) e a abundância da águia-pescadora (Pandion haliaetus), da garça-moura (Ardea cocoi) e da garça-branca-pequena (Egretta thula). O isolamento do lago influenciou a ocorrência do trinta-réis-anão (Sternula superciliaris) e do socozinho (Butorides striata), e a riqueza de habitats ao longo das margens dos lagos influenciou a maioria das espécies de aves piscívoras. Os resultados indicam que as características limnológicas e físicas de lagos são determinantes da variação espacial na abundância e ocorrência de aves piscívoras em sistemas de lagos de água preta na Amazônia Central Brasileira.
|
20 |
Variação da estrutura e da biomassa fitoplanctônica na Lagoa Itapeva (Litoral Norte do Rio Grande do Sul) em função da hidrodinâmicaBecker, Vanessa January 2002 (has links)
As lagoas costeiras em geral exibem reduzidas profundidades máximas, sendo portanto, ambientes altamente vulneráveis às oscilações dos fatores climáticos, em particular o vento. Movimentos da água em zonas pelágicas são fortemente influenciados por mudanças no tempo, as quais promovem mudanças no plâncton. A biomassa é uma importante variável em ecossistemas aquáticos uma vez que representa a quantidade de energia estocada em certo nível trófico da comunidade biológica. O trabalho teve como hipótese principal do trabalho que o vento (principal fator determinante na hidrodinâmica da Lagoa Itapeva), influencia diretamente a biomassa fitoplanctônica. Períodos de ausência de ventos ou ventos fracos provocam uma homogeneidade da comunidade, devido á estabilidade da coluna d’água, propiciando eventos de florações com alta biomassa e baixa diversidade. Outra hipótese formulada é que há variação espaço-temporal da biomassa, da diversidade de espécies e das diferentes frações de tamanho na Lagoa Itapeva, no período estudado. O objetivo do trabalho foi determinar o efeito do vento, principal fator hidrodinâmico da Lagoa Itapeva, sobre a comunidade fitoplanctônica em termos de biomassa, diversidade de espécies e categorias de tamanho. A Lagoa Itapeva é a primeira lagoa do Sistema Lagunar de Tramandaí no sentido N→S. Foram realizadas análises espaciais, formando-se três pontos de amostragem (Norte, Centro e Sul) ao longo do maior eixo longitudinal da lagoa, aliada a uma escala temporal diária (turnos de amostragem: 6h, 10h, 14h e 18h) e sazonal (quatro estações do ano), procurando estabelecer padrões e relações com os fatores hidrodinâmicos (velocidade e direção de vento, e nível d’água). Durante o estudo a Divisão Cyanophyta foi a responsável pelos elevados valores de biomassa observados nos pontos de amostragem. Este fato deve-se principalmente às florações de Anabaena circinalis durante as campanhas sazonais. A biomassa foi a variável que melhor se relacionou com os fatores físicos (nível d’água e velocidade média do vento) pela ação dos ventos de quadrantes predominantes que resultavam num fetch efetivo longo. Neste estudo foram apresentados índices de diversidade de espécies calculados através de indivíduos (H’ind) e de biomassa (H’ biom). Estes índices apresentaram estreitas relações positivas entre si. Os índices também apresentaram relações diretas e significativas com os fatores físicos (nível d’água e velocidade média do vento). Na Lagoa Itapeva, a contribuição das diferentes categorias de tamanho em função da biomassa (estimada através do biovolume), ressaltou três frações que melhor representaram a comunidade fitoplanctônica: nanoplâncton, microplâncton e netplâncton. A fração netplanctônica predominou sobre as demais frações de tamanho. A predominância desta fração sobre as outras estudadas deu-se principalmente às espécies de colônias filamentosas Aulacoseira granulata, Anabaena circinalis e A. spiroides. O comportamento da comunidade fitoplanctônica na Lagoa Itapeva sugere estar de acordo com a Hipótese de Distúrbio Intermediário de Connell (1978). Os distúrbios intensos (provocados pelos forte ventos e fetch longo) ou a falta deste (criando um ambiente estável), nos pontos de amostragem, resultaram em florações da cianobactéria Anabaena circinalis. Essas florações proveram uma densa biomassa em todo o período da pesquisa, além de promoverem a baixa diversidade através do domínio desta cianobactéria, e provocar sucessões das frações de tamanho do fitoplâncton.
|
Page generated in 0.0424 seconds