Made available in DSpace on 2015-02-24T19:48:41Z (GMT). No. of bitstreams: 1 FlavoESS.pdf: 7200814 bytes, checksum: 50030d58571208fd3287ef1805413e5f (MD5) Previous issue date: 2004-04-07 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The estuaries are important investigation zones of the actual morphodynamic and of depositional facies of recent geological history. They are constituted in important receptor means of the coastal area sediments, where the evolutionary processes occur quickly. They are also attractive means for the development of anthropic activities, which in a disordered way interfere in the active processes in the sedimentary balance of the coastal areas. Among the human interventions, the alterations of the depositional environment of mangroves in areas of tropical estuary is deserving relevance, whose implications for the environment estuarine and the coastal adjacent, they are still far to be known. Due to the interest of the sedimentologic component in the comprehension of the processes linked to the evolution of the environments estuarine and coastal adjacent, this work, aimed at the understanding of the morphodynamic coastal phenomena that comprise the region of estuarine influence of the River Curimata? / RN. It was also evaluated in the morphodynamic context the implications due to alterations of the depositional environment of mangrove by anthropic activity. The Curimata? Estuary, located in the south portion of the oriental coast of Rio Grande do Norte, in the last decades has been objective of the overwhelming occupation of the shrimp farm in areas of mangroves, which were implanted with perspectives of development in a short to medium period. On the other hand, the estuary and its region of coastal influence lacks enough information to subsidize the planning and reorganization more effective of the surrounding activities. Thus, it was intended with this work to give a contribution target tothe maintainable use of the coastal resources of this region. A series of studies using data of orbital and acoustic remote sensing, as of sediments sampling, were executed in the gutter of the estuary. The obtained results starting from the interpretation of bathymetric maps, echo sounder graphics and of distribution of sediments made possible the location of the estuary based in morpho-sedimentar criteria. The estuarine tidal flat was dissected in environments of intertidal mangroves, supratidal mangroves and apicuns with base in the integration of data of sensor optic and of radar following by the field control. The adjacent coast that is influenced by the Curimata? estuary, was segmented according to their geomorphologic characteristics, where each segment had a point of observation of the beach morphodynamic, during the period from january/2001 to february/2002. Once every month, beaches profiles, collections of sediments in the beach zones, as measurement of hydrodynamic parameters were executed. The results of the observations of the tidal environment showed that the area of estuarine influence of the Curimata? begins to suffer negative sedimentary taxes, where in some beaches, the erosive processes are already observed. The granulometric characteristics of the beach sediments start to tend for the increase of thin sand in the erosive periods. The destruction of the depositional environments of mangroves of the Curimata? estuary, to the construction of shrimp farms, can be providing the diminution of the tidal prism of the estuary, enlarging the effects of the local increasing of the sea level, through the smaller supplying of sediments to the adjacent coast. Besides this, it was verified the possibility of the sanding of the tidal channel in the margins of the destroyed areas of mangroves, where very high taxes of sedimentation of thin materials were estimated in case of these areas were preserve / Os estu?rios s?o importantes zonas de investiga??o da morfodin?mica atual e de f?cies deposicionais de hist?ria geol?gica recente. Constituem-se em importantes meios receptores de sedimentos da zona costeira, onde os processos evolutivos ocorrem rapidamente. Por sua vez s?o tamb?m meios atrativos para o desenvolvimento de atividades antr?picas, que de forma desordenada interferem nos processos atuantes no balan?o sedimentar das ?reas costeiras. Dentre as interven??es humanas, as altera??es do ambiente deposicional de manguezal em ?reas estuarinas tropicais, vem merecendo destaque, cujas implica??es para o ambiente estuarino e o costeiro adjacente, ainda est?o distantes de serem conhecidas. Devido o interesse da componente sedimentol?gica na compreens?o dos processos associados ? evolu??o dos ambientes estuarinos e costeiros adjacentes, este trabalho objetivou a compreens?o dos fen?menos morfodin?micos costeiros que envolvem a regi?o de influ?ncia estuarina do Rio Curumata?/RN. Tamb?m foi avaliada no contexto morfodin?mico as implica??es decorrentes das altera??es do ambiente deposicional de manguezal pela atividade antr?pica. O estu?rio Curimata?, localizado na por??o sul do litoral oriental do Rio Grande do Norte, nas ?ltimas d?cadas tem sido alvo da ocupa??o avassaladora da carcinicultura em ?reas em ?reas de manguezais, as quais foram implantadas com perspectivas de desenvolvimento a curto e m?dio prazo. Por sua vez, o estu?rio em pauta como a sua regi?o de influ?ncia costeira carecem de informa??es suficientes para subsidiar o planejamento e reordenamento mais eficazes das atividades de seu entorno. Assim, pretendeu-se com este trabalho dar uma contribui??o voltada ao uso sustent?vel dos recursos costeiros dessa regi?o. Uma s?rie de levantamentos utilizando dados de sensoriamento remoto orbitale ac?stico, como de amostragem de sedimentos, foram realizados na calha do estu?rio. Os resultados obtidos a partir da interpreta??o de mapas batim?tricos, sonogr?ficos e de distribui??o de sedimentos possibilitam a setoriza??o do estu?rio com base em crit?rios morfossedimentares. A plan?cie de mar? estuarina foi dissecada em ambientes de manguezais de intermar?, manguezais de supramar? e apicuns com base na integra??o de dados de sensores ?pticos e de radar seguidos do controle de campo. A costa adjacente que ? influenciada pelo estu?rio Curimata?, foi segmentada de acordo com suas caracter?sticas geomorfol?gicas, onde cada segmento teve um ponto de observa??o da morfodin?mica praial, durante o per?odo de janeiro/2001 a fevereiro/2002. Uma vez a cada m?s foram realizados perfis praiais, coletas de sedimentos nas zonas de praia, como medi??o de par?metros hidrodin?micos. Os resultados das observa??es do ambiente praial evidenciaram que a ?rea de influ?ncia estuarina do Curimata? passa a sofrer taxas de sedimenta??o negativas, onde em algumas praias j? s?o os processos erosivos. As caracteriza??es granulom?tricas dos sedimentos praiais passam a atender para o aumento de areias finas nos per?odos erosivos. A destrui??o dos ambientes deposicionais de manguezais do estu?rio Curimata? para constru??o de fazendas de camar?o, podem estar proporcionando a diminui??o do prisma de mar? do estu?rio ampliando os efeitos do aumento do n?vel do mar local, atrav?s do menor suprimento de sedimentos para a costa adjacente. Al?m disso, verificou-se a possibilidae do assoreamento do canal de mar? na margem das ?reas de manguezais destru?das, onde alt?ssimas taxas de sedimenta??o de materiais finos foram estimadas caso estas ?reas fossem preservadas

Mangroves are heterogeneous, complex ecosystems and detainers o ecological, social and economic relevance. This argument evoked the investigation of the responses of the mangroves to the environmental variations as much in macroscale as in microscale. For this purpose, in general, the research investigated the action of the weather and of the relative sea level over the potential distribution of Avicennia L.; Laguncularia racemosa (L.) Gaertn f.; and Rhizophora mangle L., on the northern and northeastern brazilian coasts, in the time scale 6.000 before present, 2015 and 2050, as well as the phenotypic plasticity of the leaves of the mangroves of Real-Piauí-Fundo estuary complex, due to abiotic and anthropogenic factors that affect the floristic populations on the Southern coast of Sergipe, Brazil. The deductive method and the General Systems Theory have built the theoretical line for the research. On the analysis of the influence of climatic requirements and the influence on the relative sea level for the potential distribution of mangroves, the models generated from this tool of maximum entropy (MAXENT) showed variations of adequability areas in different scenarios. They also highlighted the influence of the annual temperature and the vertical distance to the nearest drainage as important variables on the predictions. From another point of view, to verify the occurrence of variations of shape and size on the leaves of the mangroves on the inferior, middle and superior estuaries of the Real-Piauí-Fundo estuary, in order to examine the phenotypic plasticity of the leaves, and which way the variation patterns are related to the sedimentological, climatic, and salinity of the water factors, samples of the flora, of sediment, of water, and of 450 leaves of A. schauerianna Stapf and Laechm, 600 leaves of Laguncularia racemose (L.) Gaertn f, and 600 for Rhizophora mangle. In the morphometric analysis, 3 anatomic marks and 16 anatomic semimarks were used on the previously digitalized leaf. The analyses revealed that both the leaf lamina and the size of the leaf showed significant variations among the three estuaries (p< 0.01). Then, even in microscale, tendencies of variation in shape and size of the leaves of the mangroves in the three sampling areas occur, submitted to various environmental pressures. With the purpose of evaluating the vulnerability of the mangroves of estuary complex, among anthropogenic tensors and the possible relation of these tensors with the phenotypic plasticity of the leaf, the methodology was created from systematic observations; from the fixation of attributes of anthropic tension; from the setting of weights for the group of anthropogenic tensors acting of mangroves; from the establishment of levels of vulnerability; and from the analyses of linear regression among shape, size and anthropic tensors. The sector with higher vulnerability is the superior estuary. But, all the areas are submitted to the risks of human actions. The results also showed that both the shape and the size of the leaves of A. schauerianna and R. mangle had significant values (p< 0.01), in contrast to L. racemosa. When concluding and making suggestions, the thesis indicates it´s possible to recreate the ecological history of the environments, to understand the phenomena of the present, both from the predictive modeling, and from the morphogeometric evaluations, and subsidize actions of the mangrove conservations, in order to avoid future losses of the mangrove flora. / Os manguezais são ecossistemas heterogêneos, complexos e detentores de relevância ecológica, social e econômica. Esta assertiva suscitou a investigação das respostas dos mangues às variações ambientais tanto em macroescala, como em microescala. Para tanto, de forma geral, a pesquisa investigou a atuação do clima e do nível relativo do mar sobre a distribuição potencial de Avicennia L.; Laguncularia racemosa (L.) Gaertn.f.; e Rhizophora mangle L., no litoral das regiões norte e nordeste do Brasil, na escala temporal 6.000 antes do presente (A.P.), 2015 e 2050, bem como a plasticidade fenotípica das folhas dos mangues do complexo estuarino Real-Piauí-Fundo, decorrentes de fatores abióticos e antropogênicos que afetam populações florísticas no litoral sul de Sergipe, Brasil. O método dedutivo e a Teoria Geral dos Sistemas constituíram o fio condutor teórico para construção da pesquisa. Na análise da influência de requerimentos climáticos e de influência no nível relativo do mar para distribuição potencial dos mangues, os modelos gerados a partir da ferramenta de Máxima Entropia (MAXENT) mostraram variações de áreas de adequabilidade nos distintos cenários. Eles também destacaram a influência da temperatura anual e da distância vertical à drenagem mais próxima como variáveis de importância nas predições. Por outro ângulo, para verificar a ocorrência de variações de forma e tamanho das folhas de mangues nos estuários inferior, médio e superior do complexo estuarino Real-Piauí-Fundo, a fim de examinar a plasticidade fenotípica das folhas e de que maneira os padrões de variação estão relacionados aos fatores sedimentológicos, climáticos e de salinidade da água, foram coletadas e analisadas amostras da flora, de sedimento, água e de 450 folhas para A. schaueriana Stapf e Laechm, 600 para Laguncularia racemosa (L.) Gaertn.f.e e 600 para Rhizophora mangle L. Na análise morfométrica foram utilizados 3 marcos e 16 semimarcos anatômicos ao longo da folha previamente digitalizada. As análises revelaram que tanto a forma da lâmina foliar, como o tamanho das folhas apresentaram variações significativas entre os três estuários (p<0.01). Logo, mesmo em microescala, ocorrem tendências de variação na forma e tamanho das folhas de mangues nas três áreas de amostragem, submetidas às diferentes pressões ambientais. Quanto à forma e tamanho, não existiu efeito de alometria (p< 0.01). Com o propósito de avaliar a vulnerabilidade dos mangues do complexo estuarino, em meio aos tensores antropogênicos e a possível relação destes com a plasticidade fenotípica foliar, a metodologia foi construída a partir de observações sistemáticas; da fixação de atributos de tensão antrópica; da determinação de pesos para o conjunto de tensores antropogênicos atuantes sobre os mangues; do estabelecimento de níveis de vulnerabilidade; e das análises de regressão linear entre forma, tamanho e tensores antrópicos. O setor de maior vulnerabilidade é o estuário superior. Porém, todas as áreas estão submetidas aos riscos das ações humanas. Os resultados apontaram também que tanto a forma como o tamanho das folhas de A. schaueriana e R. mangle possuíram valores significativos (p<0.01), ao contrário da L. racemosa. Ao concluir e fazer sugestões, a tese indica que é possível reconstruir a história ecológica dos ambientes, entender os fenômenos do presente, tanto a partir da modelagem preditiva, como das avaliações morfogeométricas, e subsidiar ações de conservação dos mangues, a fim de evitar futuras perdas da flora de manguezal.

This study examined the effects of the January 2010 cold spell on mangrove utilizing coral reef fishes off the southeast coast of Florida, USA, in the vicinity of Biscayne National Park (BNP). An ongoing, fishery-independent mangrove visual survey documenting fish assemblages in BNP provided data from the years 1998 to 2014 for examination. Of particular interest were the presence, abundance, and size structure for five mangrove utilizing coral reef fishes: sergeant major (Abudefduf saxatilis), yellowfin mojarra (Gerres cinereus), schoolmaster snapper (Lutjanus apodus), gray snapper (Lutjanus griseus), and great barracuda (Sphyraena barracuda). These species were selected for analysis due to their economic and ecologic importance, their potential as environmental indicators, their connectedness to multiple habitats, and their abundance within the available data set. Data were collected using a modified visual ‘belt transect’ method, consisting of 60 m2 transects running parallel to the mangrove shorelines. Data for average length of fish were reconstructed to form standard normal distributions and the resulting lengths were assigned to various age-classes to create species-specific length-frequency distributions. Variations in presence and abundance were examined across three time periods (1998-2009; 2010-2011; 2012-2014), as well as comparisons of length-frequency distributions. Following the January 2010 cold spell, the presence and abundance values for the two years immediately following the event were significantly decreased compared to the years prior to the cold spell for most of the five species at either mainland (ML) or leeward key (LK) locations. Additionally, the presence and abundance estimates typically remained statistically decreased when compared against the remaining years in the available data set. The size structures for the majority of the five species at either location, however, were not consistently significantly different between the three time periods, as was hypothesized. Instead, the analyses showed mixed results, with the size structure typically shifting towards smaller individuals immediately following the event. These findings suggest that drops in water temperature resulting from cold spells are capable of directly impacting mangrove utilizing reef fish species, albeit to varying degrees depending on various factors, such as physiological tolerances, ecological life history strategies, and habitat requirements.

Inshore tropical and subtropical estuaries harbor a relatively high abundance and diversity of organisms. Specifically within estuaries, mangrove and seagrass habitats provide shelter and food for a plethora of organisms, through some or all their life histories. Given the biological connection between offshore coral reefs and coastal estuaries, there is a critical need to understand the underlying processes that determine distribution and abundance patterns within mangrove-seagrass habitats. The predatory fish assemblage within the mangrove and seagrass beds of Biscayne Bay, Florida (USA), was examined over 24-hr. time periods along a distance and habitat gradient from the mangrove edge and nearshore environment (0–300 m) to farshore (301–700 m) seagrass beds. This thesis also investigated the occurrence, distribution and timing of reef fish movement between offshore coral reef habitat and inshore seagrass beds over 24-hr periods. Results indicate that fish predators differed over both the sampling period and with distance from mangrove edge. The results also demonstrated reef fishes move into Biscayne Bay at dusk and exit at dawn by utilizing Broad Creek Channel as a passageway. This work supports the idea of diel migration of selected reef fishes to inshore seagrass beds and highlights the importance of connective channels between habitats. The results suggest that the degradation or loss of seagrass habitat could differentially impact the life-history stages of reef fish species.

Community-based management of natural resource (CBNRM) projects have commonly failed to deliver conservation and development benefits. This thesis examined how the theoretical assumptions of common pool resource (CPR) theory have contributed to the indifferent performance of CBNRM projects. Evidence was gathered from two CBNRM case studies in Zanzibar to show that CPR institutional design does not sufficiently acknowledge the politics or social relations of project sites. Moreover, these limitations reduce CPR theory's explanatory power and the functionality of CBNRM projects. This is because CPR theory's influence on CBNRM projects is to frame people with fixed identities and related interests as 'rational resource users', rather than people enrolled in multiple network relations with differentiated means of influence, interests and responsibilities. Actor-oriented theory is used to show that CBNRM would benefit from a shift in the correlation with institutional design factors to understanding the operation of power and conflict at project sites. These findings suggest that currently CBNRM projects are too mired in concern about regulating the 'direct' relationship between resource users and conservation objectives, with problematic implications. It is shown that actor-oriented theory is more sensitive to the different capacities, interests and strategies of actors in CBNRM institutional transformation processes. While actor-oriented theory does not offer a parsimonious or predictive theory to reform CPR theory or CBNRM policy, it can provide insights into pre-project conditions and emergent practice useful for explaining project interventions.

The Everglades is a sub-tropical coastal wetland characterized among others by its hydrological features and deposits of peat. Formation and preservation of organic matter in soils and sediments in this wetland ecosystem is critical for its sustainability and hydrological processes are important divers in the origin, transport and fate of organic matter. With this in mind, organic matter dynamics in the greater Florida Everglades was studied though various organic geochemistry techniques, especially biomarkers, bulk and compound specific δ13C and δD isotope analysis. The main objectives were focused on how different hydrological regimes in this ecosystem control organic matter dynamics, such as the mobilization of particulate organic matter (POM) in freshwater marshes and estuaries, and how organic geochemistry techniques can be applied to reconstruct Everglades paleo-hydrology. For this purpose organic matter in typical vegetation, floc, surface soils, soil cores, and estuarine suspended particulates were characterized in samples selected along hydrological gradients in the Water Conservation Area 3, Shark River Slough and Taylor Slough. This research focused on three general themes: (1) Assessment of the environmental dynamics and source-specific particulate organic carbon export in a mangrove-dominated estuary. (2) Assessment of the origin, transport and fate of organic matter in freshwater marsh. (3) Assessment of historical changes in hydrological conditions in the Everglades (paleo-hydrology) though biomarkes and compound specific isotope analyses. This study reports the first estimate of particulate organic carbon loss from mangrove ecosystems in the Everglades, provides evidence for particulate organic matter transport with regards to the formation of ridge and slough landscapes in the Everglades, and demonstrates the applicability of the combined biomarker and compound-specific stable isotope approach as a means to generate paleohydrological data in wetlands. The data suggests that: (1) Carbon loss from mangrove estuaries is roughly split 50/50 between dissolved and particulate carbon; (2) hydrological remobilization of particulate organic matter from slough to ridge environments may play an important role in the maintenance of the Everglades freshwater landscape; and (3) Historical changes in hydrology have resulted in significant vegetation shifts from historical slough type vegetation to present ridge type vegetation.

Above-ground biomass was allometrically estimated to quantify the amount of mangrove species in selected quadrats of Xuan Thuy National Park. Physicochemical properties of surrounding waters and soils were measured and treated stochastically by correlational analysis with estimated biomass values. Correlation results suggested that qualities of surrounding waters and soils are not the principal inhibitors of mangrove growth in Xuan Thuy. The available historical records infer that the main factor of mangrove loss in the past lay on land reclamation for shrimp aquaculture. In addition, results of correlation analysis showed geographical coincidence of mangrove fragmentation with influence area of water channeling used for aquaculture activities. Furthermore, the distribution of anomalous values of metals concentration was corresponding with anthropological activities associated to clam aquaculture and sand extraction. Based on the aforementioned analysis and the information on anthropological activities in the buffer zone of Xuan Thuy, were provided basic information on inherent environmental stressors of ecosystems in Xuan Thuy National Park. / Sinh khối trên mặt đất đã được ước tính theo phương pháp tương quan sinh trưởng để đưa ra số lượng các loài đước trong các mẫu vuông được lựa chọn tại Vườn quốc gia Xuân Thủy. Các đặc tính hóa-lí của những vùng nước và đất xung quanh đã được đo đạc và xử lí ngẫu nhiên bằng cách phân tích tương quan với những giá trị sinh khối ước tính. Kết quả tương quan cho thấy rằng chất lượng nước và đất xung quanh không phải là những thước đo chính cho tốc độ phát triển cây đước ở Xuân Thủy. Những ghi chép cũ đã kết luận rằng việc sử dụng đất để nuôi tôm là tác nhân chính dẫn tới suy giảm loài đước trong quá khứ. Bên cạnh đó, kết quả phân tích tương quan cho thấy sựtrùng hợp về mặt địa lý giữa sự phân mảnh của loài đước và những vùng nước bị ảnh hưởng do việc nuôi trồng thủy sản. Hơn nữa, sự phân bố bất thường của các giá trị đo mức độ tập trung kim loại cũng tương ứng với các hoạt động nuôi trồng thủy sản và khai thác cát của con người. Những phân tích nêu trên và nghiên cứu về hoạt động của con người tại vùng đệm của Xuân Thủy sẽ cung cấp những thông tin cơ bản về những mối đe dọa môi trường hệ sinh thái tại Vườn Quốc Gia Xuân Thủy.

The impact of natural disasters is often exacerbated by a disparity between resources for relief and recovery. When the barrio of Punta Santiago in Puerto Rico was devastated by Hurricane Maria in September of 2017, many of its residents lived in the remains of their homes for over a year while they rebuilt from wind damage and flood waters that rose over 6 feet. As climate change leads to an even more constrained timeline for response with increasingly frequent and intense storms, the future of Punta Santiago and other coastal communities worldwide will necessitate strategies ranging from nature-based shore protection systems, coastal setbacks, and managed retreat. This thesis investigates the time disparate processes of disaster relief, recovery, and climate adaptation through the lens of their impact upon the interdependent identities of people and place as informed by theorists and designers including J.B. Jackson and Patrick Geddes. My approach works from the scale of the Antón Ruíz watershed to the delta to uncover the historical and contemporary processes that knit people in the region to the land. I identify commonalities in the immediate recovery needs and long-term resiliency of the community and ecosystems, and seek to support ongoing globally significant research of the rare coastal systems surrounding Punta Santiago. The proposed design, a causeway linking the coast to the hills, dovetails disaster relief and recovery with climate adaptation by providing a persistent connection that restores and reveals the dynamic coastal landscape. / Master of Landscape Architecture / Global warming is correlated with an increase in sea level rise, atmospheric moisture (water content in the air), and surface sea temperatures. The body of research around the complex interaction of these factors is growing, but current projections are that warmer seas will cause more intense hurricanes. Coastal communities, particularly those with fewer economic resources, bear the brunt of this trend and recovery is more difficult with each passing storm. After Hurricane Maria struck in September 2017, many residents of the barrio of Punta Santiago in Puerto Rico lived in the remains of their homes for over a year with little resources to rebuild from the severe wind damage and flood waters that rose over 6 feet. Recovery is still underway almost two years later. A sustainable way forward for Punta Santiago and other coastal communities worldwide necessitates strategies ranging from natural shore stabilization techniques like mangrove buffers and living reefs to restrictions on coastal development, and even the relocation of communities. This thesis investigates the time disparate processes of disaster relief, recovery, and climate adaptation through the lens of their impact upon the interdependent identities of people and place as informed by theorists and designers including J.B. Jackson and Patrick Geddes. My approach works from the scale of the Antón Ruíz watershed to the delta to uncover the historical and contemporary land use that knit people in the region to the land. I identify commonalities in the immediate recovery needs and long-term resiliency of the community and ecosystems, and seek to support ongoing globally significant research of the rare coastal systems surrounding Punta Santiago. The proposed design, a causeway linking the coast to the hills, dovetails disaster relief and recovery with climate adaptation by providing a persistent connection that restores and reveals the dynamic coastal landscape.

<p>The thesis analyses relationships between ecological and social systems in the context of coastal ecosystems. It examines human impacts from resource extraction and addresses management and governance behind resource exploitation. The main premises are that a lack of ecological knowledge leads to poor ecosystem management and that the dichotomy between social and natural systems is an artificial one. The thesis illustrates the importance of basing resource management on the ecological conditions of the resource and its ecosystem. It also demonstrates the necessity of accounting for the human dimension in ecosystem management and the challenges of organising human actions for sustainable use of ecosystem services in the face of economic incentives that push users towards short-term extraction.</p><p>Many Caribbean coral reefs have undergone a shift from coral to macroalgal domination. An experiment on Glovers Reef Atoll in Belize manually cleared patch reefs in a no-take zone and a fished zone (Papers I and II). The study hypothesised that overfishing has reduced herbivorous fish populations that control macroalgae growth. Overall, management had no significant effect on fish abundance and the impacts of the algal reduction were short-lived. This illustrated that the benefits of setting aside marine reserves in impacted environments should not be taken for granted. </p><p>Papers III and IV studied the development of the lobster and conch fisheries in Belize, and the shrimp farming industry in Thailand respectively. These studies found that environmental feedback can be masked to give the impression of resource abundance through sequential exploitation. In both cases inadequate property rights contributed to this unsustainable resource use. </p><p>The final paper (V) compared the responses to changes in the resource by the lobster fisheries in Belize and Maine in terms of institutions, organisations and their role in management. In contrast to Maine’s, the Belize system seems to lack social mechanisms for responding effectively to environmental feedback. The results illustrate the importance of organisational and institutional diversity that incorporate ecological knowledge, respond to ecosystem feedback and provide a social context for learning from and adapting to change.</p>

Made available in DSpace on 2016-08-19T18:20:37Z (GMT). No. of bitstreams: 1 Carolina Mattosinho de Carvalho Alvite.pdf: 6763080 bytes, checksum: d171930fac0eadfa71fb881a91e48018 (MD5) Previous issue date: 2008-09-28 / INSTITUTO INTERNACIONAL DE EDUCAÇÃO DO BRASIL / The Brazilian north coast has the largest continuous area of mangroves on the planet and hosts large groups of manatees, aquatic mammal critically endangered. This research examines the efforts of fix point methodology of observation of manatees on relevant sites of occurrence, from data collected while on the beach in Guarapiranga (GUA), São José de Ribamar and on Ilha do Gato (IGA), Baía do Tubarão. This article discusses the application of population index for manatees in a ecological-environmental study on IGA (02°31'09, 81"S, 43°37'09,13" W), Mapari estuary, serving as a methodological basis to be replicated in other parts of the coast. From the application of index developed with data from fixed point and the characterization of the environmental area, the study provides evidence to infer the relative abundance of the population and it trends over the years, discussing aspects of spatial and temporal use of estuary. Was characterized: temperature, salinity, pH, conductivity, depth, current speed, tides fluctuations, rainfall, biomass of salt-marsh (Spartina alterniflora), and density of plants/seedlings of mangrove. The region showed a seasonal variation marked by two regimes of water, rain (January-July) and dry (August-December), with annual rainfall of 1,704mm. The oceanographic parameters ranged from tides: salinity (FLOOD=14.8; EBB=1.5), conductivity (FLOOD=27.1; EBB=6.3mS/cm), speed of current (FLOOD=46; EBB=88m/s). The tide height ranged from 0.0-5.4m. Biomass of S. alterniflora ranged from 860g/m2(RAIN) to 430g/m2(DRY) and density of plants/seedlings of 74ind/m2(RAIN) to 21ind/m2(DRY). Variations between rain/dry seasons influenced the availability of fresh water and food resources, important factors in the choice of areas for manatees. The estuary was shown with strong influence of daily tide fluctuations, reflecting changes in salinity, current speed, depth and access to plant resources by manatees. Between 2004/2007, manatees were monitored in 1241 days (GUA = 625, IGA = 616). The population analysis carried out in two sites of Maranhão indicated a trend of reducing population between 2004 and 2006, with stabilization between 2006 and 2007. The IGA had the highest relative abundance and showed to be important site of occurrence of manatees, which used as an area of reproduction, parental care, food and rest. IGA in the number of manatees seems to have relation with the seasons, being sighted in greater numbers in the rainy season. Variations during the tides also shown to influence the pattern of use of the IGA, and the manatees were more frequent in the tides ebb and flood. The main type of human activity in the IGA was not motorized boat and it had no negative influence on the occurrence of fish-horse. Knowledge about characteristics of coastal ecosystems is essential for development of appropriate conservation strategies for manatees in the Brazilian north coast. / O litoral norte do Brasil possui a maior área contínua de manguezais do planeta e abriga importantes grupos de peixes-bois-marinhos, mamífero aquático criticamente ameaçado de extinção. Esta pesquisa analisa o esforço da metodologia de observação de peixes-bois por meio de plataformas fixas em sítios de relevante ocorrência, a partir dos dados coletados simultaneamente na praia de Guarapiranga (GUA), São José de Ribamar, e na barra da Ilha do Gato (IGA), Baía do Tubarão. Também é discutida a aplicação de indicadores populacionais e ecológicos para peixes-bois em estudo de caso na barra da Ilha do Gato (02°31 09,81 S; 43°37 09,13 W), estuário do rio Mapari, servindo de base metodológica para ser replicada em outros pontos da costa. A partir da aplicação dos indicadores elaborados com os dados de ponto fixo e da caracterização ambiental da área, a pesquisa fornece elementos para inferir a abundância relativa da população e como esta se comporta ao longo dos anos, discutindo aspectos da utilização espacial e temporal do estuário. Para caracterização ambiental da IGA, foram levantados os seguintes parâmetros: temperatura (ar-água), salinidade, pH, condutividade, profundidade, velocidade de corrente, amplitude de marés, precipitação pluviométrica, biomassa de marisma (Spartina alterniflora), densidade de plântulas de mangue. A região mostrou uma variação sazonal do regime hidrológico: chuva (janeiro-julho) e seca (agosto-dezembro), com precipitação pluviométrica anual de 1704mm. Os parâmetros oceanográficos médios variaram entre as marés: salinidade (ENCH=14,8, VAZ=1,5), condutividade (ENCH=27,1, VAZ=6,3 mS/cm), velocidade de corrente (ENCH=46; VAZ=88 m/s). A altura da maré variou entre 0,0-5,4m. A biomassa de S. alterniflora variou de 860g/m2(chuva) a 430g/m2(seca) e a densidade de plântulas de 74 ind/m2(chuva) a 21 ind/m2(seca). As variações entre os períodos de seca e chuva influenciaram na disponibilidade de água doce e recursos vegetais, fatores determinantes na escolha de áreas pelos peixes-bois. O estuário mostrou-se com forte influência da variação diária nos regimes de maré, refletindo em mudanças na salinidade, velocidade de corrente, profundidade e acesso aos recursos vegetais pelos peixes-bois. Entre 2004/2007, os peixes-bois foram monitorados em 1.241 dias (GUA=625, IGA=616). As análises populacionais realizadas nos dois sítios do Maranhão indicaram uma tendência de redução populacional entre 2004 e 2006, com estabilização entre 2006 e 2007. A Ilha do Gato apresentou a maior abundância relativa e mostrou ser importante sítio de ocorrência de peixes-bois, sendo utilizada como área de reprodução, cuidado parental, alimentação e repouso. Na IGA o número de peixes-bois parece ter relação com as estações do ano, sendo avistados em maior número no período chuvoso. As variações nas fases de maré também mostraram ter influência no padrão de utilização da IGA, sendo que os peixesbois estiveram mais freqüentes nas marés vazantes e cheias. A ocorrência de embarcações não motorizadas foram a atividade humana com maior freqüência na IGA e não teve influência negativa na ocorrência dos peixes-bois. O conhecimento sobre as características dos ecossistemas costeiros é essencial para a elaboração de estratégias de conservação adequadas para o peixe-boi-marinho na região norte do Brasil.