Tesi sul tema "Mangrove plants"

Mangrove forests are subjected to many environmental factors which influence species distribution, zonation patterns as well as succession. Important driving factors in these forests are salinity, water level fluctuations and available light. This study investigated the response of red mangrove (Rhizophora mucronata Lam.) seedlings to these factors in controlled laboratory experiments. Increase in salinity and prolonged inundation within estuaries are predicted impacts resulting from sea level rise due to climate change. The study investigated the effect of five salinity treatments (0, 8, 18, 35 and 45 ppt) with a semi-diurnal tidal cycle on seedling growth. In a separate experiment the effect of different inundation treatments: no inundation, 3, 6, 9 hour tidal cycles and continuous inundation (24 h) were investigated. Both morphological and physiological responses of R. mucronata seedlings were measured. There was a decrease in growth (plant height, biomass and leaf production) with increasing salinity. Seedlings in the seawater, hypersaline and no inundation treatments showed symptoms of stress, having increased leaf necrosis ("burn marks"). The highest growth occurred in the low salinity (8 ppt) treatment, but the highest photosynthetic performance and stomatal conductance occurred in the freshwater treatment (0 ppt). The typical response of stem elongation with increasing inundation was observed in the 24 hr inundation treatment. In the light and salinity combination study there were ten different treatments of five different light treatments (unshaded, 20 percent, 50 percent, 80 percent and 90 percent shade) combined with two salinity concentrations (18 and 35 ppt). In this study the seedling growth: plant height, biomass, leaf surface area and leaf production were higher in the moderate salinity (18 ppt) treatments compared to the seawater (35 ppt) treatments. Biomass in the 35 ppt experiment decreased with increasing shade as well as in the unshaded treatments. Photosynthetic performance and stomatal conductance were lower for the unshaded treatment in both 18 and 35 ppt salinity compared to all other treatments with the same salinity. This suggests that R. mucronata more shade than sun tolerant, but overall it can be concluded that the species has a broad tolerance range. The results may be relevant in mangrove rehabilitation and predicting responses to climate change. This is important as mangrove ecosystems may adapt to changing sea levels and in order to restore areas it will be necessary to choose the mangrove species which will grow best. The results may also help to increase the protection of existing mangrove habitats.

The ecology of mangrove forests on Potential Acid Sulphate soils at Bintuni Bay (132° 55' - 134° 02' E, and 2° 02' - 2° 97' S), Irian Jaya, Indonesia was studied. The annual rainfall is 3000mm and there is mixed semi-diurnal tide of 1-5.6m amplitude. The water has a varying salinity of 0-27%. Forest structure was studied in plots of 10m x 10m along three transects across Sikoroti Island and in three 50m x 50m plots in mixed Rhizophora - Bruguiera forest. All trees > 10cm trunk diameter were enumerated, measured and identified. Of the nine tree species, Rhizophora apiculata was the most dominant, followed by Bruguiera gymnorrhiza and Ceriops decandra. There was good regeneration seven years after clear-felling in plots on Amutu Besar and Amutu Kecil Islands. Small litterfall production, measured using ten 1m x 1m litter traps in each of the three 50m x 50m plots, was 11.09 t ha-1 y-1, and greatest during the wet season (December, 1.29 t ha-1 ) and least during the dry season (July, 0.61 t ha-1). The annual litterfall mineral element accession was (kg ha-1 y-1): N 240.4, P 6.1, K 43.2, Na 136.2, Ca 204.4 and Mg 48.7. Leaf decomposition of five species was studied in litterbags on the forest floor under trees of the same species. Sonneratia alba decomposed quickly with a half-life of 24 days, and Bruguiera parviflora was the slowest with a halflife of 124 days. Decomposition rates of all species followed a single exponential decay model. Leaf herbivory of young stands of Rhizophora apiculata and Bruguiera gymnorrhiza was significantly different among sites, species, plant height and leaf-age. Seed predation on six species was studied in three different sites. Twenty propagules of each species were secured by string in each of six 10m x 10m sub-plots within each of five 10m x 60m plots. On average 62.1% of the seeds were dead after 36 d. Predation was higher in the lower intertidal zone, and Avicennia alba and Bruguiera parviflora were the most predated. The results suggested that the Bintuni Bay mangroves can be sustainably managed but the best silvicultural system needs to be determined.

Manguezais são ecossistemas que se distribuem ao redor do globo e desempenham funções ecológicas que são fundamentais para os ambientes costeiros adjacentes. Além de fornecerem uma ampla variedade de organismos para o subsídio humano, são áreas de produção e exportação de matéria orgânica, e também fornecem abrigo, alimentação e local para a reprodução de diversos animais marinhos. Apesar de sua enorme importância, esse ambiente encontra-se fortemente ameaçado e sob risco de desaparecer. As árvores de mangue são o seu componente mais básico e visível, sendo consideradas bastante produtivas, com grande parte do carbono orgânico encontrado nesse ambiente sendo proveniente da liteira e raízes das plantas. Micro-organismos são extremamente diversos, dinâmicos e estão distribuídos por todo o planeta, desempenhando importantes funções ecológicas, e dentro dos manguezais, eles são responsáveis pela maioria das transformações de nutrientes. Diversos estudos apontam a importância da comunidade bacteriana para uma equilibrada manutenção dos processos que ocorrem nesse ambiente, sendo um destes a decomposição de serapilheira. Dessa forma, este trabalho teve como objetivo estudar a dinâmica da comunidade bacteriana durante o processo de degradação de material vegetal em sedimentos de manguezais do Estado de São Paulo. Para isso, foi realizado o sequenciamento em larga escala do gene rRNA 16S do domínio Bacteria presente sobre a superfície do material vegetal. Paralelamente a isto, foi feita a quantificação da emissão CO2, N2O e CH4, durante os diferentes estágios de degradação foliar e também a análise da dinâmica e estrutura das comunidades. Os resultados obtidos por meio de sequenciamento em larga escala do gene rRNA 16S apontam o filo Proteobacteria como o grupo dominante nos três manguezais estudados, independente da espécie de planta. A classe Gammaproteobacteria apresentou uma maior abundância nos estágios iniciais de decomposição do material vegetal (7 e 15 dias), sofrendo um decaimento bem acentuado nas fases mais avançadas (60 dias). A alfa diversidade sofreu um aumento ao longo do tempo, com todas as amostras exibindo valores maiores nos estágios finais do processo de decomposição foliar. Em relação à emissão de gases de efeito estufa (GGE) em tratamentos em microcosmo, para N2O e CO2 tempo e local foram significativamente importantes. Já para CH4 somente o local foi relevante nas taxas de emissão. Foi possível identificar grupos de bactérias predominantes nas fases de decomposição foliar ao longo do período estudado. Gammaproteobacteria foi uma classe que se apresentou em maior quantidade nos estágios iniciais (7 e 15 dias), enquanto Alphaproteobacteria foi um grupo mais expressivo nas fases mais avançados de degradação (30 e 60 dias).
Mangroves are ecosystems that are distributed around the globe and perform ecological functions that are critical to the adjacent coastal environments. In addition to providing a wide variety of organisms for human activities, they have high productivity and are known as areas of production and export of organic matter, and also provide shelter, food and location for reproduction of various marine animals. Despite its enormous importance, this environment is at risk of disappearing. Mangrove trees are its most basic and visible component, being considered quite productive, with most of the organic carbon found in this environment being from the litter and plant roots. Micro-organisms are extremely diverse, dynamic and are spread across the globe, contributing with important environmental roles, and within the mangroves, they are responsible for most of nutrient transformations. Several studies point to the importance of the bacterial community for the balanced maintenance of the processes that are occurring in this environment. One of the most crucial of them is the decomposition of leaf-litter. Thus, this study aimed to evaluate the dynamics of bacterial communities during the degradation of plant material on sediments of São Paulo State mangroves by high throughput sequencing of 16S rRNA gene of Bacteria present on the surface of the plant material. In parallel, we quantified the emissions of CO2, N2O and CH4 during the different stages of leaf degradation and also the analysis of the dynamics and structure of communities. The results obtained by the sequencing of the 16S rRNA gene indicate the phylum Proteobacteria as the dominant group in the three mangroves, regardless of plant species. The Gammaproteobacteria class showed a greater abundance in the early stages of decomposition of the plant material (7 and 15 days), suffering a very sharp decay in the later stages (60 days). Alpha diversity has increased over time, with all the samples showing higher values in the final stages of the leaf decomposition process. It was possible to identify groups of bacteria predominant in the stages of decomposition of plant material throughout the study period. Regarding greenhouse gas emissions (GHG) in treatments in microcosm, time and location were significantly important factors to N2O and CO2 emissions. As for CH4 only the site was relevant in emission rates. It was possible to identify groups of bacteria predominant in the stages of leaf decomposition during the studied period. Gammaproteobacteria was a class that contains the main amount in the early stages (7 and 15 days), while Alphaproteobacteria was a more significant group in the most advanced stages of degradation (30 and 60 days).

Mangrove stands are uncommon within semi-arid climates and rare within inland systems. It is uncertain whether the same environmental variables influence mangroves growing in a semi-arid climate as the trees growing in tropical and sub-tropical areas. Field studies conducted on the ecophysiological responses of the mangrove species Avicennia marina are few; however hydrological regimes are considered the key factor influencing mangrove stand zonation, structure and individual tree growth. The Gascoyne region of Western Australia provides a unique opportunity to investigate whether mangroves growing within an inland semi-arid environment display similar growth patterns and ecophysiological responses to their coastal counterparts. This study investigates the distribution, structure and condition of the mangrove A. marina growing at Lake MacLeod and coastal and riverine stands near Carnarvon, Western Australia. Hydrological categories based on freshwater inputs, tidal influences, distance from permanent water sources and sediment elevations were used to investigate the environmental conditions present within specific hydrological regimes. Mangrove tree responses to environmental conditions were evaluated by assessing above-ground biomass, shoot production, water-use efficiency, photosynthesis, specific leaf area, weight and total chloride content. The overarching objective was to determine the environmental factors influencing the presence, morphology and physiological state of A. marina growing at inland, coastal and riverine sites in a semi-arid climate. Soil moisture content, organic matter content, average and seasonal range in sediment EC, and distance from the permanent water sources were found to influence vegetation characteristics at Lake MacLeod. Soil moisture content was highest close to permanent ponds and at lower sediment elevations. Sediment salinity was highest close to pond edges, although the majority of the lake bed is hypersaline due to high evapoconcentration. The environmental gradients are complex at Lake MacLeod as a result of the unique hydrological regime. Seawater supply to permanent ponds is constant via an underground karst system which enters the lake through vents and seepages present along the western edge of the lake bed. It is evident that the constant supply of marine water is the key environmental factor supporting mangrove presence and structure. Average mangrove tree height, basal area, density and canopy cover are greatest near the permanent ponds. Mangrove density and height was also high, though patchy away from the ponds where saline seepages occurred. A high density of stunted mangroves was found on lake shorelines receiving periodic saline flooding via wind surges. Samphire cover was also greatest close to the permanent ponds, demonstrating that both mangrove and Samphire presence and importance is influenced by consistency of water availability. Sediment conditions were significantly different between inland and coastal sites, with sediment salinity and moisture content higher at Lake MacLeod. The ecophysiological responses displayed by A. marina in different categories of hydrological regimes revealed that consistency of water supply, irrespective of salinity, is an important driver of long and short-term productivity, water-use efficiency, leaf size and weight, and tree height. In general, short and long-term production was inversely proportional to distance from permanent water sources, although it was highly variable due to seepages away from the permanent ponds. Mangrove trees growing at the landward edge of coastal sites were the most water-use efficient (~ -28 δ¹³C), relative to the inland Lake MacLeod trees (~ - 26 δ¹³C), and was directly linked to water supply not quality. Photosystem health in trees growing at both the riverine stands (yield 0.66 ± 0.01) and inland stands found at greater distances from ponds (yield 0.065 ± 0.02), were significantly lower than all other trees in this study. Relative maximum electron transfer rate was also significantly lower at these sites, suggesting that the riverine trees were affected by other stresses such as herbicides. Mangrove trees near permanent water sources, or that received tidal flushing, displayed larger leaves and lower specific leaf weight, indicating that A. marina has the ability to not only tolerate hypersaline conditions but also acclimate to harsh and variable conditions via changes to ecophysiological responses and morphology. This research has developed a better understanding of how A. marina persists at Lake MacLeod and whether these trees are under greater stress as opposed to the mangroves growing at coastal stands. Sediment conditions between coastal and inland sites were significantly different, but it was distance from permanent water sources that influenced mangrove stand features. Therefore, the key environmental variable influencing distribution, structure and ecophysiological state of A. marina growing in a semi-arid climate is predominantly water availability.

The cycling of arsenic in the marine photosynthetic plants and algae was examined by analysing total arsenic concentrations and arsenic species in selected marine photosynthetic organisms from the south-east coast, NSW, Australia. A range of elements required for metabolism in photosynthetic organisms were also analysed to determine if any relationship between these elements and arsenic concentrations occurred. Organisms were selected from salt marsh and mangrove ecosystems, marine inter-tidal and estuarine environments, and two species of marine phytoplankton cultured, to represent the different marine environments that primary producers inhabit. Organisms selected were compared to species within their own environment and then a comparison made between the varying ecosystems. In the salt marsh and mangrove ecosystems, the leaves of four species, the mangrove Avicennia marina, the samphire Sarcocornia quinqueflora, the seablight Suaeda australis, and the seagrass Posidonia australis were sampled from three locations from the south-east coast of NSW using nested sampling. Mean total arsenic concentrations (mean � sd) dry mass for all locations were A. marina (0.38 � 0.18 �g g-1 to 1.2 � 0.7 �g g-1), S. quinqueflora (0.13 � 0.06 �g g-1 to 0.46 � 0.22 �g g-1), S. australis (0.03 � 0.06 �g g-1 to 0.05 � 0.03 �g g-1)and P. australis (0.34 � 0.10 �g g-1 to 0.65 � 0.26 �g g-1). Arsenic concentrations were significantly different between species and locations but were consistently low compared to marine macroalgae species. Significant relationships between As and Fe concentrations for A. marina, S. quinqueflora and P. australis and negative relationship between As and Zn concentrations for S. quinqueflora could partially explain arsenic concentrations in these species. No relationship between As and P concentrations were found in this study. All terrestrial species contained predominantly inorganic arsenic in the water extractable and residue fractions with minor concentrations of DMA in the water-soluble fraction. P. australis also contained dimethylated glycerol and phosphate arsenoriboses. The presence of arsenobetaine, arsenocholine and trimethylated glycerol arsonioribose is most likely due to the presence of epiphytes on fronds on P. australis. In contrast, macroalgae contained higher total arsenic concentrations compared to marine terrestrial angiosperms. Total arsenic concentrations also varied between classes of algae: red macroalgae 4.3 �g g-1 to 24.7 �g g-1, green macroalgae 8.0 �g g-1 to 11.0 �g g-1 and blue green algae 10.4 �g g-1 and 18.4 �g g-1. No significant relations were found between As concentrations and concentrations of Fe, Co, Cu, Mn, Mo, Mg, P and Zn concentrations, elements that are required by macroalgae for photosynthesis and growth. Distinct differences between algal classes were found for the proportion of arsenic species present in the lipid and water-soluble fractions, with green algae having a higher proportion of As in lipids than red or estuarine algae. Acid hydrolysis of the lipid extract revealed DMA, glycerol arsenoribose and TMA based arsenolipids. Within water-soluble extracts, red and blue-green algae contained a greater proportion of arsenic as inorganic and simple methylated arsenic species compared to green algae, which contained predominantly glycerol arsenoribose. Arsenobetaine, arsenocholine and tetramethylarsonium was also present in water-soluble extracts but is not normally identified with macroalgae and is again likely due to the presence of attached epiphytes. Residue extracts contained predominantly inorganic arsenic, most likely associated with insoluble constituents of the cell. Mean arsenic concentrations in the green microalgae Dunaliella tertiolecta were 13.3 �g g-1 to 14.5 �g g-1, which is similar to arsenic concentrations found in green macroalgae in this study. Diatom Phaeodactylum tricornutum arsenic concentrations were 1.62 �g g-1 to 2.08 �g g-1. Varying the orthophosphate concentrations had little effect on arsenic uptake of microalgae. D. tertiolecta and P. tricornutum metabolised arsenic, forming simple methylated arsenic species and arsenic riboses. The ratio of phosphate to glycerol arsenoriboses was higher than that normally found in green macroalgae. The hydrolysed lipid fraction contained DMA arsenolipid (16-96%) with minor proportions of phosphate arsenoribose (4-23%). D. tertiolecta at f/10 phosphate concentration, however, contained glycerol arsenoribose and another arsenic lipid with similar retention as TMAO as well as DMA. The similarities between arsenic species in the water-soluble hydrolysed lipids and water-soluble extracts, especially for P. tricornutum, suggests that cells readily bind arsenic within lipids, either for membrane structure or storage, releasing arsenic species into the cytosol as degradation of lipids occurs. Inorganic arsenic was sequestered into insoluble components of the cell. Arsenic species present in D. tertiolecta at lower phosphate concentrations (f/10) were different to other phosphate concentrations (f/2, f/5), and require further investigation to determine whether this is a species-specific response as a result of phosphate deficiency. Although there are similarities in arsenic concentrations and arsenic species in marine photosynthetic organisms, it is evident that response to environmental concentrations of arsenic in uncontaminated environments is dependent on the mode of transfer from the environment, the influence of other elements in arsenic uptake and the ability of the organism to metabolise and sequester inorganic arsenic within the cell. It is not scientifically sound to generalise on arsenic metabolism in �marine plants� when species and the ecosystem in which they exist may influence the transformation of arsenic in higher marine organisms. There is no evidence to suggest that angiosperms produce AB as arsenic is mostly present as inorganic As, with little or no arsenic present in the lipids. However, marine macro- and microalgae both contain lipids with arsenic moieties that may be precursors for AB transformation. Specifically, the presence of TMA and dimethylated arsenoribose based arsenolipids both can transform to AB via intermediates previously identified in marine organisms. Further identification and characterization of As containing lipids is required.

Ecotone entre les continents et l’océan, la mangrove couvre l’essentiel du littoral des régions intertropicales. Elle constitue un écosystème unique, façonné par un environnement très contraignant. Environnement à haute valeur scientifique et socio-économique, la mangrove subit cependant de multiples menaces. Le suivi de cet écosystème et la compréhension de sa dynamique constituent maintenant des priorités. Dans ce contexte, notre étude a d’abord porté sur l’amélioration de l’estimations des surfaces de mangrove au niveau mondial et sur le suivi de leur évolution, par l’utilisation de la télédétection. L’importance du proche infrarouge dans l’identification des mangroves a été alors mis en évidence. Nous nous sommes ensuite focalisés sur une région à forte activité hydro-sédimentaire : les mangroves des côtes subissant l’influence du fleuve Amazone. De l’individu au peuplement, du suivi de terrain à l’analyse des données de télédétection, nous avons alors caractérisé la dynamique de ces mangroves au travers de deux de ces phases essentielles. - Le développement d’un peuplement après la colonisation de nouveaux espaces (exemple des bancs de vase en Guyane française) : Le rôle de la microtopographie pour l’implantation des plantules, les phénomènes de croissance et la phénologie des jeunes individus ont été précisés. - La régénération de la mangrove adulte (exemple des chablis au Brésil) : La répartition des plantules à l’intérieur des chablis et l’importance là encore de la microtopographie ont été observées. Les possibilités de cartographie des chablis par télédétection ont été explorées. Des relations étroites entre cycles sédimentologiques et cycles biologiques ont ainsi été mis en évidence. Notre exploitation de données de télédétection variées, de l’optique à basse résolution au laser, participe à une meilleure utilisation de ces techniques pour l’étude et le suivi des écosystèmes de mangrove
Land-Ocean ecotone, the mangrove covers almost all the tropical littoral. It constitutes a unique ecosystem, built by a very constraining environment. Environment with high scientific and socio-economic value, the mangrove undergoes however multiple threats. The monitoring of this ecosystem and the comprehension of it dynamic contitute priorities now. In this context, our study focuses first on the improvement of the mangrove surfaces estimates at world level and on the monitoring of their evolution, by tremote sensing. The importance of the near infra-red for the mangroves identification was then highlighted. We then specially study an area of high hydro-sedimentary dynamic: mangroves under the Amazon river influence. From the individual to the settlement, from ground monitoring to remote sensing data analysis, we then characterized the dynamic of these mangroves through two key-phases: - The settlement growth after colonization of a new environment (example of the mud banks in French uiana): The role of microtopography for the seedlings establishment, the growth phenomena and the phenology of the young individuals were specified. - The regeneration of the adult mangrove (example of forest gap in Brazil): The distribution of the seedlings inside gaps and the importance there still of microtopography were observed. The possibilities of gap cartography by remote sensing were explored. Close connections between sedimentological cycles and biological cycles were thus highlighted. Our use of varied remote sensing data, from optical low resolution to Lidar, takes part in a better use of these technics for the study and the monitoring of the mangrove ecosystems

Manguezais são ecossistemas localizados na confluência de terra e mar, característicos de áreas tropicais e subtropicais, cobrindo cerca de 18,1 milhões de hectares do planeta. A grande biodiversidade encontrada nestes ambientes ressalta a importância da busca por conhecimentos à seu respeito, como o estudo sobre novos princípios ativos derivados de microrganismos endofíticos presentes nas plantas de manguezais. Desta forma, o propósito do presente trabalho foi determinar a diversidade genética da comunidade de fungos endofíticos presentes em folhas e ramos das principais espécies arbóreas de manguezais de Cananéia e Bertioga (situados no estado de São Paulo, Brasil), e avaliar o potencial biotecnológico destes fungos em relação à produção de antibióticos contra os patógenos humanos Staphylococcus aureus e Escherichia coli, e contra o fitopatógeno Xanthomonas axonopodis citri . Os resultados da primeira etapa do trabalho, que envolveu o isolamento e a caracterização de fungos endofíticos filamentosos, mostraram que a comunidade fúngica associada às plantas de manguezais é formada por pelo menos 35 gêneros diferentes, sendo que os gêneros mais frequentes foram Diaporthe, Fusarium, Trichoderma, Colletotrichum e Xylaria. Grande parte dos gêneros encontrados neste trabalho é de fungos de solo, indicando que eles estão adaptados às condições adversas dos manguezais. Os resultados mostraram que, dentre as linhagens produtoras de antibiótico, 29,41% pertencem ao gênero Diaporthe, o qual apresentou maior frequência na comunidade fúngica estudada. Após a avaliação de 344 fungos quanto ao potencial de atividade antimicrobiana, foi selecionada a linhagem 41.1(1) de D. phaseolorum, um endófito de folha de Laguncularia racemosa, para elucidação da estrutura química do seu antibiótico purificado. Por meio das técnicas de Ressonância Magnética Nuclear e de Espectrometria de Massas o antibiótico foi identificado como ácido 3-hidroxipropiônico o qual apresentou atividade frente aos patógenos humanos Staphylococcus aureus e Salmonella tiphy. A estrutura química deste antibiótico foi modificada por meio de reação química de esterificação de Fischer-Speier para avaliar a relação da estrutura química e atividade biológica deste composto. O produto final da reação química de esterificação do antibiótico ácido 3-hidroxipropiônico não apresentou atividade antimicrobiana, indicando que o grupo hidroxila removido na reação é importante na atividade farmacológica desse composto. Além disso, a linhagem 41.1(1) de D. phaseolorum foi transformada geneticamente pelo sistema Agrobacterium tumefaciens, visando a obtenção de transformantes deficientes para produção de antibiótico e, com isso, a identificação de genes relacionados com a via de biossíntese do antibiótico ácido 3-hidroxipropiônico. A análise das sequências que flanqueiam o T-DNA, obtidas por TAIL-PCR, mostraram que os genes interrompidos nos transformantes estão relacionados com proteínas de domínios conservados envolvidos com diferentes funções como: translação de proteínas, homeostase do íon orgânico Mg2+, transporte intracelular, migração, adesão e proliferação celular e outras funções celulares. A caracterização da biblioteca de agrotransformantes constitui uma ferramenta importante para o estudo da biologia molecular de fungos que produzem compostos bioativos por meio do seu metabolismo secundário.
Mangroves are ecosystems situated beyond land and sea. They are more frequently found in tropical and subtropical areas englobing around 18.1 millions of hectares in the planet. The great biodiversity found in these ecosystems shows the importance of researching them, including studies regarding new compounds derived from endophytic fungi that inhabit these ecosystems. Therefore, the goal of this study was to determine the genetic diversity of the fungal endophytic community found in leaves and branches of the main arboreal species from mangrove of Cananéia and Bertioga (situated in São Paulo state, Brazil), and to evaluate the biotechnological potential of these fungi concerning the production of antibiotics against the human pathogens Staphylococcus aureus and Escherichia coli, and against the phytopathogen Xanthomonas axonopodis citri . The results of the first part of this work, including the isolation and characterization of the filamentous endophytic fungi, showed that the mangrove fungal community is made up of at least 35 different genera, from which the most frequent are Diaporthe, Fusarium, Trichoderma, Colletotrichum and Xylaria. Most of the fungal genera found in this study come from soil, which suggests that they are adapted to the adverse conditions of mangroves. The results show that among the antibiotic-produncing strains, 29.41% belong to the genus Diaporthe, which was the most frequently found in the studied fungal community. After the analysis of 344 fungi regarding the antibiotic activity potential, a strain of D. phaseolorum (a leaf endophyte of Laguncularia racemosa) was selected to unveil the chemical structure of their purified antibiotic. The nuclear magnetic resonance and the mass spectrometry techniques allowed the identification of the antibiotic as 3-hidroxypropionic acid, which displayed activity against the pathogens Staphylococcus aureus and Salmonella tiphy. The chemical structure of this antibiotic was modifyed by the chemical reaction of Fischer-Speier sterification in order to evaluate the chemical structure and biological activity of this compound. The final product of the chemical reaction of 3-hidroxipropionic acid sterification had no antibiotic activity, which suggests that the hydroxil group removed from the reaction is important to the pharmachological activity of this compound. Additionally, the strain 41.1(1) of D. phaseolorum was genetically transformed by the Agrobacterium tumefaciens system, in order to generate antibioticdeficient transformants, which would help to identify genes related to the biosynthesis pathway of the 3- hidroxypropionic acid antibiotic. The TAIL-PCR analysis revealed that the interrupted genes in the tranformants are related to proteins from conserved domains involved in different functions such as protein translation, Mg2+ ion homeostasis, intracellular transport, migration, adhesion and cellular proliferation and other cellular functions. The characterization of the agrotransformants library is an important tool to unveiling the molecular biology of fungi that produce bioactive compounds by the secondary metabolism.

Les forêts de mangrove contribuent de manière significative au flux d'énergie, au cycle des nutriments et du carbone dans l'océan côtier, étant un puits pour le CO2 atmosphérique. Les forêts de mangroves sont très productives et stockent une quantité élevée de carbone à la fois dans leurs sols et dans leur biomasse.Au cours de la décomposition de la litière, les nutriments et le carbone peuvent être recyclés ou exportés vers les écosystèmes adjacents par l'action des marées. La mangrove de Can Gio (Ho Chi Minh Ville, Vietnam), dégradée par l'épandage de défoliants pendant la guerre du Vietnam, a pu être restaurée grâce à la replantation et à la régénération naturelle. À ce jour, la forêt de mangrove de Can Gio est la plus grande forêt de mangrove contiguë au Vietnam, et est devenue la première réserve biosphère UNESCO dans ce pays. L'objectif principal de cette thèse était de caractériser le cycle du carbone dans la forêt de mangrove tropicale.Les résultats de cette thèse ont permis de:- Développer des équations allométriques permettant d’estimer la biomasse aérienne de la forêt plantée de mangroves de l’espèceRhizophora apiculatadans le sud du Vietnam;- Calculer les stocks de carbone totaux dans différents peuplements de mangrove se développant sous le climat tropical du sud du Vietnam;- Caractériser les taux de décomposition de la litière et évaluer la dynamique des nutriments et des métaux traces au cours des processus de dégradation de la litière, ainsi que l'évolution de δ13C pendant la décomposition;- Déterminer la variabilité saisonnière des flux de CO2 à différentes interfaces: sol-air, eau-air et tronc-air, et caractériser les profils de concentration en CO2 dans la canopée
Mangrove forests significantly contribute to energy flow, nutrient and carbon cycling in the coastal ocean, being a sink for atmospheric CO2. Mangroves forests are highly productive and store high amount of carbon both in their soils and in their biomass. During leaf litter decomposition, nutrients and carbon can be recycled or exported to adjacent ecosystems by the tidal action. Can Gio mangrove, degraded by the spraying of defoliants during the Vietnam War, successfully recovered through replantation and natural regeneration after 40 years. To date, the Can Gio mangrove forest is the largest contiguous mangrove forest in Vietnam, and became the first Mangrove Biosphere Reserve in this country. The main objective of this PhD thesis was to characterize carbon cycling within the Can Gio mangrove forest, which is a tropical one.The results of this PhD thesis allowed to: - Develop allometric equations and to estimate the aboveground biomass of Rhizophora apiculata Blume planted mangroves forest in Southern Vietnam; - Calculate the total carbon stocks in different mangrove stands developing under the tropical climate of Southern Vietnam; - Characterize the leaf litter decomposition rates, and assess nutrients and trace metals dynamics during litter decay processes, as well as the evolution of δ13C during decay; - Determine the seasonal variability CO2 fluxes at different interfaces: soil-air, water-air and trunk-air, and to characterize CO2 concentrations profiles in the canopy

There are large gaps in the coverage of critical ecological processes related to the movement of individuals or genes (i.e. dispersal), which is critical for determining the spread and persistence of populations across space. In this dissertation we investigate understudied but important aspects of the dispersal process in mangroves, with as the main objective the reduction of parameter and model uncertainty. Models rarely incorporate realism and complexity at the level of emigration, transfer and immigration phases, hampering reliable predictions of dispersal patterns and long-term population dynamics under different climate change scenarios.

Mangrove ecosystems function at the edge of land and sea, often covering large intertidal areas along (sub)tropical coastal regions worldwide. Mangroves can live in these highly dynamic and demanding environmental conditions via a series of remarkable adaptations. They produce buoyant seeds and fruits (propagules) that disperse at the ocean surface (i.e. hydrochory - see cover image).

Despite their ecological and economical value, about 40 % of original mangroves have been lost worldwide during the last 50 years due to excessive exploitation and development. Deforestation, degradation and conversion to other land uses like intensive shrimp farming and agriculture have reduced and fragmented these ecosystems at an alarming rate. Climate change, probably most pronouncedly via changes in sea level, poses another important threat.
Doctorat en Sciences
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Les mangroves du Sénégal se caractérisent par une couverture partielle des estrans. En effet, proportionnellement à la salinité des eaux et des sols, la partie haute des estrans est trop salée et acide pour la vie des palétuviers. Ces espaces sont appelés les tannes. L'interface entre la mangrove et les tannes fluctue dans le temps, en réaction aux variations de l'hydrosystème, suivant les fluctuations climatiques. Ainsi, les fluctuations de la limite mangrove-tanne définissent la plage de métastabilité et de résilience de l'écosystème de mangrove dans les estuaires du Sénégal. Une période de sécheresse entre la fin des années 60 et le milieu des années 90 a entraîné la conversion des mangroves en tannes en raison de l'augmentation de la salinité. Cependant, depuis la fin des années 1990, les précipitations sont revenues à des niveaux proches de la moyenne centenaire, favorisant ainsi la régénération des mangroves dans les estuaires du Saloum et de la Casamance. Dans la partie sahélo-soudanienne du Sénégal, le delta du Saloum, en milieu semi-aride, présente des caractéristiques de marge d'aire de répartition en raison des salinités extrêmes. La mangrove dans ce delta réagit principalement de manière spontanée aux fluctuations environnementales, offrant ainsi une opportunité d'étudier sa résilience face aux perturbations hydro-climatiques. En outre, des lacunes de connaissances entravent la compréhension des raisons de cette dynamique. La pondération de l'importance des facteurs qui influencent la dynamique spatiale de la mangrove est donc enjeu scientifique. Par conséquent, une méthodologie basée sur la mise en synergie de la télédétection, de données in-situ ainsi que la modélisation statistique et spatiale a permis d'appréhender la réaction de la mangrove aux changements de l'hydrosystème. Cette approche implique tout d'abord l'observation et la description de la dynamique des populations d'espèces en marge de l'aire de répartition sur un état de référence actuel. Puis l'identification des changements de régime dans les dynamiques environnementales et leur impact sur la répartition des populations d'espèces au cours des dernières décennies ont été envisagés. Enfin, des expérimentations ont été menées pour évaluer la réponse des processus de reproduction aux seuils de transitions environnementales identifiées. Une modélisation spatio-temporelle a d'abord permis de reconstituer ces changements de régimes. Ensuite, la fenêtre d'opportunité de germination des espèces en fonction de la variabilité temporelle hydro-climatique a pu être caractérisée afin d'identifier l'instabilité potentielle du système face aux perturbations.Les résultats de cette thèse indiquent que les fluctuations climatiques des dernières décennies ont affecté la structure spatiale de la répartition des espèces. La mangrove du Saloum a montré une résilience globale face aux changements pluviométriques, oscillant entre 500 mm et 700 mm de précipitation annuelle, notamment dans les parties du delta où les concentrations en sel sont les plus élevées. De plus, les conditions hydro-climatiques actuelles semblent favoriser une trajectoire de la mangrove allant du tanne vers une couverture partielle de l'estran, où Avicennia germinans trouve rarement les conditions propices à son établissement et à la colonisation de l'interface mangrove-tannes. Sa capacité d'établissement semble nécessiter des cumuls pluviométriques plus importants et un moment plus précoce dans la saison des pluies. Ainsi, les résultats de cette thèse mettent en évidence, de manière plus précise, qu'un seuil pluviométrique de 600 mm peut probablement induire des modifications de l'organisation spatiale des espèces de la mangrove, en fonction de son atteinte en août ou en fin d'année
The mangroves of Senegal are characterized by a partial coverage of intertidal zones. Proportionally to the salinity of water and soil, the upper part of the intertidal zone is too salty and acidic for mangrove life to thrive. These areas are referred to as 'tannes'. The interface between the mangrove and the tannes fluctuates over time, in response to variations in the hydrosystem, following climatic fluctuations. Thus, the fluctuations in the mangrove-tanne boundary define the range of metastability and resilience of the mangrove ecosystem in the estuaries of Senegal. A period of drought between the late 1960s and the mid-1990s led to the conversion of mangroves into tannes due to increased salinity. However, since the late 1990s, precipitation levels have returned to near the centennial average, thus promoting mangrove regeneration in the estuaries of Saloum and Casamance. In the Sahelian-Sudanian part of Senegal, the Saloum delta, in a semi-arid environment, exhibits characteristics of a distribution range margin due to extreme salinities. The mangrove in this delta primarily responds spontaneously to environmental fluctuations, providing an opportunity to study its resilience in the face of hydro-climatic disturbances. Furthermore, knowledge gaps hinder the understanding of the reasons behind this dynamic. Weighing the importance of factors influencing the spatial dynamics of the mangrove is therefore a scientific challenge. Consequently, a methodology based on the synergy of remote sensing, in-situ data, as well as statistical and spatial modeling has enabled us to grasp the mangrove's reaction to changes in the hydrosystem. This approach first involves the observation and description of the dynamics of species populations at the distribution range margin in a current reference state. Then, the identification of regime changes in environmental dynamics and their impact on the distribution of species populations over the past decades was considered. Finally, experiments were conducted to evaluate the response of reproduction processes to identified environmental transition thresholds. A spatio-temporal modeling first allowed the reconstruction of these regime changes. Then, the germination opportunity window of species based on hydro-climatic temporal variability was characterized in order to identify the potential instability of the system in the face of disturbances. The results of this thesis indicate that climatic fluctuations in recent decades have affected the spatial structure of species distribution. The mangrove of Saloum has shown overall resilience to rainfall changes, oscillating between 500 mm and 700 mm of annual precipitation, particularly in parts of the delta with the highest salt concentrations. Furthermore, current hydro-climatic conditions seem to favor a trajectory of the mangrove from tannes towards a partial coverage of the intertidal zone, where Avicennia germinans rarely finds conditions conducive to its establishment and colonization of the mangrove-tannes interface. Its establishment capacity appears to require higher cumulative rainfall and an earlier time in the rainy season. Thus, the results of this thesis highlight, more precisely, that a rainfall threshold of 600 mm can likely induce modifications in the spatial organization of mangrove species, depending on whether it is reached in August or at the end of the year

Les Polluants Organiques Persistants (POPs) sont des composés hautement toxiques, persistants dans l’environnement, une capacité de transport à grande distance et accumulation sur les phases riches en matière organique. Compte tenu de la vulnérabilité des écosystèmes aquatiques aux pollutions et la rareté des données sur les POPs en Afrique, cette thèse examine les niveaux de Pesticides organochlorés (POCs), Polychlorobyphelyes (PCBs) et Hydrocarbures polyaromatiques (HAPs) dans le bassin versant du Lac Barombi (LBW) et la Mangrove estuaire du Wouri (MEW). Dans le LBW, les POCs détectés étaient, l’endosulfan, l‘hexachlorocyclohexanes (HCHs), le dieldrine and l’aldrine. Aucun OCPs n’a été détecté dans les eaux et les plus fréquemment détectés étaient les HCHs avec des teneurs plus élevées dans les sols par rapport au sédiments (ruisseaux et Lac). Le ratio α/γ-HCH ont indiqué l’utilisation récente du lindane (γ-HCH). La présence des OCPs a été attribué à l’agriculture et la pêche. Les teneurs en PAHs étaient plus élevées dans les sédiments lacustres que les autres échantillons. Les sources pyrolytiques de HAPs étaient dominantes plus spécifiquement la combustion d’herbes, du bois ou le charbon. Les recommandations pour la qualité des sédiments (SQGs) un faible risque de toxicité sur les organismes aquatiques. Dans les MEW, les teneurs en HAPs dans les sédiments étaient 10 fois plus élevés que les PCBs et Pesticides Chlorés (PCLs). Les PCLs les plus abondant étaient l’endosulfan, l’alachlor, l’heptachlor, le lindane (γ-HCH) et le DDT pour lesquels les métabolites indiquent une utilisation récente. La contribution des HAPs pyrolytiques était dominante
Persistent Organic Pollutants (POPs) are compounds that are highly toxic to living organisms, persistent in the environment, undergo long distance transport and accumulate in organic-rich phases (sediments and fatty tissues). Given the vulnerability of aquatic ecosystems to pollution and scarcity of data on POPs in Africa and, this thesis examines the level of Organochlorinated Pesticides (OCPs), Polychlorobiphenyls (PCBs) and Polyaromatic hydrocarbons (PAHs) in the Lake Barombi Watershed (LBW) and Wouri Estuary Mangrove (WEM) in Cameroon. In LBW, OCPs detected were endosulfan, hexachlorocyclohexanes (HCHs), dieldrin and aldrin. No OCPs were detected in water and the most frequently detected were HCHs with higher levels in soil than sediments (stream and lake). The α/γ-HCH ratio indicated recent use of lindane. The presence of OCPs is attributed to agriculture and fishing. PAH levels were higher in lake sediments than other samples. Pyrolytic sources of PAHs were predominant specifically combustion of grass, wood or coal. Sediment Quality Guidelines (SQGs) indicated low ecological risks to aquatic life. In the WEM, PAHs levels in sediments were more abundant than Chlorinated Pesticides (CLPs) and PCBs. The most abundant CLPs were endosulfan, alachlor, heptachlor, lindane (γ-HCH) and DDT for which metabolites pattern revealed recent use. PAHs ratios showed a predominant pyrolytic input. The presence of POPs in the WEM is mainly attributed to disease vector control (malaria), municipal waste dumps, industrial emissions and effluents, open burning of wastes, petroleum exploitation and harbour activities. SQGs implied low to moderate predictive biological toxicity

Mangroves and saltmarshes are ecologically important coastal ecosystems; unfortunately, these low-lying coastal ecosystems are vulnerable to global climate change. As sea-levels rise, mangroves are expected to shift their distribution landward towards higher elevation sites that are occupied by other plants, including saltmarsh taxa. Therefore, mangrove recruits at the leading edge of expansion may interact with diverse assemblages of saltmarsh plants, and these interactions could influence the success of mangrove encroachment into higher tidal-elevation areas. The purpose of the research presented here was to investigate empirically the ecological interactions that may influence the recruitment of the black mangrove, Avicennia germinans, into saltmarsh habitats. Saltmarsh plants frequently occurred at the landward boundary of mangrove forests at two sites selected for field studies along the west coast of Florida: Cannon Island and Upper Tampa Bay Park. On Cannon Island, two different field tests investigated mangrove propagule entrapment and dispersal within saltmarsh vegetation. In the first experiment, the entrapment of mangrove propagules within saltmarsh plants, exhibiting different growth forms, was examined during seasonal high tide events. Natural polyculture plots retained a mean (±;SE) 59.3% (±;11.0) of emplaced propagules. Monocultures varied in their propagule retention capacities with plots of S. virginicus retaining on average 65.7% (±;11.5) of transplanted propagules compared to 7.2% (±;1.8) by B. maritima and 5.0% (±;1.9) by S. portulacastrum. Monocultures of the salt marsh grass, Sporobolus virginicus, and natural saltmarsh polycultures containing S. virginicus retained significantly more propagules than either of two succulent plants (i.e., Batis maritima and Sesuvium portulacastrum). Using digital images, saltmarsh plant structure was quantified; the number of entrapped mangrove propagules displayed a significant and positive correlation (r2 = 0.6253, p = 0.00001) with the amount of structure provided by saltmarsh plants. Therefore, the first field study identified structural and functional differences between saltmarsh plants. A second field study employed marked propagules in order to further examine the dispersal patterns of propagules at saltmarsh boundaries comprised of plants with different growth forms (i.e., grass vs. succulent) during seasonal high tides. Saltmarsh plant boundaries erected by taxa with distinct growth forms differentially influenced the proportion of propagules that dispersed seaward and the distance propagules moved seaward. In fact, nearly twice as many propagules dispersed seaward at boundaries erected by succulent plants compared to boundaries composed of grass. The results of this field study support my previous findings that propagule dispersal is comparatively lower in saltmarsh grass than in succulent saltmarsh plants. The findings from these two field studies suggest that the permeability of boundaries formed by saltmarsh plants may modulate landward dispersal of A. germinans propagules. The final field study was conducted at Upper Tampa Bay Park, where a second species of saltmarsh grass, Monanthochloe littoralis, co-occurred with the grass, S. virginicus, and succulent saltmarsh plants to form a mosaic landscape of saltmarsh plant patches. Patches were weeded to create 3 saltmarsh treatments: 1) M. littoralis monoculture; 2) S. virginicus monoculture; and 3) polycultures containing both grasses and at least one other saltmarsh taxa. Propagules of A. germinans were emplaced into saltmarsh patches and followed for 11 weeks. On the last sampling date, the greatest number of A. germinans (n = 51) had successfully established as seedlings within the M. littoralis monoculture plots. In contrast, only 20 (22% of the propagules initially emplaced) A. germinans seedlings established in S. virginicus monoculture plots. These findings suggest that among grass taxa, species identity influences mangrove establishment success, which builds upon our previous findings that demonstrated that saltmarsh growth form (i.e., grass vs. succulent) influenced mangrove propagule dispersal. Combined the findings from these field studies indicate that interactions among the early life history stages of black mangroves and neighboring plants influence mangrove recruitment. Specifically, these field studies provide empirical evidence that the species composition of saltmarsh plants influences mangrove propagule dispersal and seedling establishment. The work presented here has implications for understanding the suite of ecological interactions that may influence mangrove encroachment into saltmarsh habitats at higher tidal elevations as sea-levels rise.

Coastal communities will be most affected by global climate change and are important to study to understand current and future ecological processes. The current model for global climate change predicts a change in rainfall, which will alter the salinity of coastal systems. Given the presence of eutrophication in many coastal waters, it is important to understand the effects that this increase in nutrients, coupled with changes in salinity, will have on these communities. This study was conducted to understand the effect of salinity increase on the growth and herbivory of the black mangrove, Avicennia germinans, in the presence of increased nutrients. Explicitly, the effects of changing salinity (high, medium, and low) were coupled with fertilizer additions of nitrogen, phosphorus, both, or no fertilizer. Nutrient enrichment differentially affected the growth and herbivory of the plants between salinity zones. The medium salinity zone consistently produced the greatest increases in growth and herbivory. Added nutrients did not have an effect on growth in the low salinity zone. However, added nitrogen increased some growth variables in the medium salinity zone and added phosphorus increased some growth variables in the high salinity zone. Phosphorus also increased herbivory. The results point to diverse processes acting along the salinity gradient. There appears to be differential N- and P-limitation along the gradient. Additionally, the growth differences indicate abiotic and biotic limitations across the salinity gradient, with debilitating salinity acting in the high salinity zone and competition acting in the low salinity zone.

Disturbance can take various forms and are characteristic of any ecosystem including mangroves. When maintained within certain allowable limits, disturbances permits maintenance of a given stable state which is equivalent to resilience hence the ecological status is not compromised. Disturbances may disrupt the natural balance of processes within such ecosystems including changes in sediment budgets and salinity and tidal regimes. As such, it may trigger a series of responses in tree establishment and development. While such responses may be displayed in loss of stability of a forest and may culminate in irreversible degradation of the system, disturbances could also result in improved performance of physiological processes and consequently tree growth. It may equally lead to the development of adaptive mechanisms to counteract the resultant otherwise stressful effects. Sediment accretion is one of the important natural processes within the mangrove environment particularly in the face of relative sea level rise. In each case, sediment fluxes are gradual and while the trees thrive from the benefits of terrestrial sediment, the system ensures balance in elevation for possible sea level rise scenario. However, abrupt and/or rapid sediment input leading to partial burial of the trees may be detrimental to the trees development in the short term and the entire ecosystem in the long run. But how are ecophysiological processes affected before the mangroves trees die from partial sediment burial? What is the threshold below which normal tree functioning is ensured.The main objective of this study was to understand the impacts of disturbance on mangrove trees, as individuals and as an assemblage. Specifically the study targeted large sedimentation on selected ecophysiological processes (phenology, water transport), root development and general physiognomy and hence its impact on wood formation in mangroves. A survey was also done on the extent of wood exploitation and other human activities, in order to obtain background information on the environmental management in the area and hence to help create an integrated picture of the evolving mangrove ecosystem in the human-nature context.Main question: What is the significance of sedimentation in shaping the ecological status of mangrove forests?
Doctorat en Sciences
Author's maiden name: Judith Auma OKELLO
Due to a technical Di-Fusion bug it was not possible to input the correct date of the defense. The correct date is Thursday 30 June 2016.
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La mangrove subit des conditions écologiques limitantes(inondation,salinité,instabilité du substrat)qui conduisent à étudier sa dynamique en termes d'inertie (résistance aux pertubations),et de succession végétale (nouveaux équilibres issus de changements durables du milieu). Les sites non encore reconstitués 10 ans après mortalité massive naturelle survenue dans le dernier demi-siècle, ont été inventoriés en Guadeloupe et en Martinique, et classés statistiquement en 3 type dominés respectivement par Rhizophora mangle (type 1),Avicennia germinians (type 2) et un mélange de ces deux èspèces (type 3). Le caratère physiographiques ,édaphiques et floristiques de chaque type déterminent leur sensibilité aux aléas climatiques (cyclones pour le type 1,sécheresse pour les types 2 et 3). La régénération du couvert dépend d'anomalies de la dispersion des diaspores et de l'adaptatibilité des plantules de chaque èspèce aux nouvelles conditions du milieu. La modélisation de l'évolution de la végétation de chaque type,en fonction du régime actuel de pertubations et des scenarii régionaux possibles du changement climatique ,tend à souligner l'intérêt de faciliter la reconstitution du couvert végétal de ces espaces côtiers. Cela contribuera ,en palliant aux effets de ce Changement global,à garantir les conditions environnementales nécessaires à la recherche de "léquilibre durable"du développement des îles tropicales
Mangroves have to face limiting ecological conditions(i. E. ,waterlogging,salinity,substrate instability),which leads to deal with their vegetation dynamics in terms of inertia (resistance to disturbances),of resiliency(recorvery following disturbance),and of plant sucession (new balances set up by long-lasting environnemental changes). In the islands of Guadeloupe and Martinique,sites still exhibiting recovery failure 10 years after natural mass mortality events that occured within the past half-century, were assessed and statistically split into 3 types,dominated respectively by Rhizophora mangle (type 1). Avicennia germinians (type 2) and a mix of these two species(type 3). Physiographic,soil and floristic features of each type influence their sensitivity to climatic hazards (cyclones for type 1,droughts for types 2 and 3). Vegetation recovery depends on abnomalities of seedling dipersal and on seedling adaptability of each spesies to the new environnemental conditions. Modelling vegetation evolution of each type,under current disturbance regime,and taking into account possible patterms of climate change in the Caribbean,tends to lend support to the idea of enhancing forest regeneration within those coastal areas. This will allow to meet the environnemental requirements challenging climate change mitigation ,and stepping towards a "sustainable balance" of tropical islands' development

Changing environmental conditions often impose stressful growing conditions in plant communities. Until now, morphological plasticity, i.e. polymorphic growth physiognomies of plants, has not been sufficiently studied as a pivotal strategy for the whole ecosystem adaptation to environmental stress. We consider mangrove ecosystems as suitable models to provide insights on this subject. In the thesis, I investigate the ecological significance of tree morphological plasticity in the structural development and the dynamics of mangrove forests. I conducted field experiments in two regions located on both sides of the Amazon River mouths i.e. in French Guiana and North Brazil. Forest inventories were carried out in contrasting mangrove stands in both regions. The thesis combines empirical analysis of field data, terrestrial laser scanning (TLS), and mechanistic, individual-based computer simulations. We published results that proved the TLS-based analysis of individual tree structure useful for a better knowledge on biomass allocation between trunk and branches in tall and large Avicennia germinans mangrove trees reaching 45 m high and 125 cm of trunk diameter. Combining structural descriptions of A. germinans trees found in both sites, I highlighted the site-specific differences in tree allometries. The study suggests that regional differences in mangrove tree structure and function could be captured through better description of crown metrics, and that selected indicators of local morphological plasticity and consequent stand structure could generate a plus-value in the understanding of mangrove stand dynamics across contrasting coastal environments. Beyond the extension of allometric models to large Avicennia trees, we proposed new biomass equations with improved predictive power when crown metrics is taken into account. Additionally, we developed a novel software tool, named Lollymangrove, based on the AMAPStudio suite of software, with the objective of maximizing the potential of further field descriptions and modeling works. Lollymangrove allows standardized forest data capture, 3D visualization of structural data, aboveground biomass computations from a configurable module and export formats for forest dynamics and remote sensing models. Simulation experiments were conducted by means of the spatially explicit, individual-based stand model BETTINA_IBM. This model describes the important mechanism of water uptake limited by salt stress, and revealed insights into the relation between environmental conditions, allometric variations and biomass partitioning of mangrove trees, and stand characteristics. The simulation results suggest close matches with observed ecological patterns (e.g., tree allometries, mortality distributions, and self-thinning trajectories) under higher salinity. In low salinity conditions, however, the current parameterization underestimates the maximum tree height and diameter, and consequently, aboveground biomass and self-thinning trajectories of forest stands. This suggests that the morphology of trees under low levels of salinity are explained by further regulation mechanism(s) that still need to be addressed in a subsequent model improvement. Overall, this work has essentially pointed out the need to elucidate how morphological plasticity relates with structural development of forest stands. It establishes that TLS measurements and structural data analysis associated to efforts for integrative software and mechanistic modelling works could link mangrove dynamics to fast-changing coastal processes.

The southern coast of Shoal Bay, near Darwin, Northern Territory is a small, well vegetated chenier plain. Chenier plains are prograded coastal mudflats that support a number of long narrow ridges formed from sand and shell debris, that run parallel to the coast. Mangrove communities on the mudflat occur in zones, also parallel to the coastline, indicating species preference for protection, depth and duration of tidal inundation and level of salinity. Chenier plains are thought to be formed through fluctuations in sediment supply resulting in, episodic coastal progradation, and coastal erosion and ridge deposition above the level of high tide. Some of the literature suggests that progradation may be aided by the seaward mangrove zones trapping sediments, while erosion of the mudflats and subsequent ridge formation can be attributed to high energy storm activity, such as that of a tropical cyclone. This study is involved with examining the recent history of the chenier plain at Shoal Bay, in regard to the effects of cyclone Tracy, which struck the area on December 25, 1974. The storm devastated large areas of the central mangrove zones, those of Bruguiera, Ceriops and Rhizophora, mostly by windthrow. The seaward mangrove zones, such as that of Avicennia, and the landforms were mostly unaffected by the storm winds, and the storm surge associated with the cyclone was relatively small, as it occurred in conjunction with a neap high tide. The overall effects of cyclone Tracy on the chenier plain were much less than those described for other storms in the literature. All of the changes that have occurred on the Shoal Bay chenier plain over the period examined can be explained by normal wave and tide action, and do not require a high energy event.

La mangrove est un écosystème complexe qui se développe sur les zones intertidales, le long des littoraux (sub)tropicaux. Dû à sa production primaire élevée, couplée à une grande capacité de séquestration du carbone organique, la mangrove a été nommée écosystème à « Carbone Bleu ». Toutefois, le changement climatique à venir, et particulièrement les augmentations en CO2 atmosphérique et en température ainsi que la hausse du niveau marin, pourraient modifier son fonctionnement. Dans de ce contexte, les objectifs étaient de (i) comprendre comment les variations eustatiques passées ont pu impacter les stocks de carbone enfouis dans les sols de mangrove, afin de mieux prévoir l’effet de la future hausse du niveau marin, (ii) caractériser les émissions de CO2 et de CH4 depuis les sols et la colonne d’eau dans la mangrove, et (iii) évaluer l’impact de la hausse des concentrations en CO2 atmosphérique et de la durée d’immersion sur la physiologie de plantules de palétuviers. L’augmentation des concentrations CO2 atmosphérique modifiera la productivité des palétuviers, notamment en stimulant leur activité photosynthétique, facilitant ainsi leurs capacités à coloniser de nouveaux espaces disponibles du fait de la hausse des océans. Cette hausse aura également un effet conséquent sur les stocks de carbone dans les sols, comme nous l’avons montré pour les variations eustatiques de l’Holocène tardif, impliquant également une migration des strates de mangrove. Finalement, les émissions de CO2 et de CH4 vers l’atmosphère sont non négligeables, tout particulièrement celles émises depuis la colonne d’eau, qui devront être pris en compte dans les futurs bilans carbone de l’écosystème
Mangroves are complex and unique ecosystems that develop on intertidal areas along (sub)tropical coastlines. Due to their position, they are considered as major ecosystems in the coastal carbon cycle. Thanks to their high primary productivity, coupled with a high carbon sequestrating capacity in both biomass and soils, mangroves have been called “Blue Carbon” ecosystems. However, future climate change, and particularly increases in atmospheric CO2 concentrations, temperatures and sea-level rise, may alter its functioning. Within this context, the objectives were to (i) understand how eustatic variations may have impacted soil carbon stocks by the past, in order to better predict the effects of future sea-level rise, (ii) characterize CO2 and CH4 emissions from the soil and also from the water column within the mangrove forest, and (iii) evaluate the impact of future increase in atmospheric CO2 concentrations and in sea-level may affect the physiology of young mangrove seedlings. Increases in atmospheric CO2 concentrations will modify either the seedlings productivity and photosynthetic activity, therefore facilitating their ability to colonize new accommodation spaces due to the rising sea-level. This increase in sea-level will also have a consequent impact on soil carbon stocks, as we showed for the past eustatic variations of the late Holocene, also implying a migration of mangroves stands. Eventually, CO2 and CH4 emissions to the atmosphere were non-neglectable, particularly the one emitted from the water column

Les palétuviers de mangrove sont des plantes qui se développent entre la terre et la mer sous les climats tropicaux. Cette position d'interface confère aux mangroves un rôle écologique et socio-économique important. Entre autres elles servent de protection de biodiversité, elles protègent les côtes contre l'érosion du littoral, et séquestrent de quantités importantes de dioxyde de carbone. Au Gabon, cependant les mangroves font face à une pollution urbaine. Dans cette pollution on retrouve les métaux lourds (ETM), les hydrocarbures aromatiques polycycliques (HAP) et bien d'autres déchets selon leurs localisations. Grâce à son système racinaire développé, notamment pour les espèces R. racemosa et A. germinans, ces palétuviers absorbent les polluants et les concentrent dans les racines et le tronc. L'objectif de cette étude était de montrer l'impact de la pollution sur les propriétés du bois de la mangrove. Les bois issus du site pollué aux HAP présentaient un bois à aubier non différencié, une diminution de la teneur en extractibles et une faible durabilité aux attaques fongiques. S'agissant des bois issus du site pollué aux ETM, avaient une durabilité naturelle plus importante que celle des bois collectés sur les sites non pollués. Ces résultats ont été comparés avec les échantillons de Hêtre (Fagus sylvatica) imprégnés par des ETM aux laboratoires qui ont montré la même durabilité plus importante face aux champignons
Mangrove mangroves are plants that grow between land and sea in tropical climates. This interface position gives mangroves an important ecological and socio-economic role. Among other things, they serve to protect biodiversity, protect the coasts against erosion of the littoral, and sequester significant quantities of carbon dioxide. In Gabon, however, mangroves face urban pollution. This pollution includes heavy metals (ETM), polycyclic aromatic hydrocarbons (PAHs) and many other wastes depending on their location. Thanks to its developed root system, especially for the species R. racemosa and A. germinans, these mangroves absorb pollutants and concentrate them in the roots and trunk. The objective of this study was to show the impact of pollution on the properties of mangrove wood. The wood from the PAH-polluted site showed undifferentiated sapwood, reduced extractives content and low durability to fungal attack. The wood from the ETM polluted site had a higher natural durability than the wood collected from the unpolluted sites. These results were compared with samples of beech (Fagus sylvatica) impregnated with ETM at the laboratories which showed the same higher durability to fungi

Orientador: Silvia Rodrigues Machado
Coorientador: Camilla Rozindo Dias Milanez
Resumo: A poluição por metais tem sido um dos principais problemas ambientais, tendo em vista a sua toxicidade, persistência no ambiente e bioacumulação. Os manguezais frequentemente são expostos a esses contaminantes, sendo o ferro um dos metais presentes em maior concentração no sedimento e com papel biogeoquímico importante quanto à precipitação e ciclagem de metais. Investigamos o acúmulo, a distribuição e a eliminação de ferro em Avicennia schaueriana Stapf & Leechm. ex Modenke, Laguncularia racemosa (L.) C.F. Gaertn. e Rhizophora mangle L. submetidas a diferentes concentrações de ferro. Para esse estudo, propágulos das três espécies estudadas foram coletados em campo e cultivados em meio nutritivo de Hoagland. Após o cultivo, as plantas foram submetidas a quatro tratamentos pela adição de 0 (controle), 10, 20 e 100 mg L-1 de Fe(II)SO4 no meio nutritivo. As plantas foram então coletadas, sendo realizadas análises químicas, anatômicas, histoquímicas e ultracitoquímicas. Parte dessas análises também foi feita em campo para comparação dos dados. Os resultados mostraram que a placa de ferro é local de grande acúmulo de ferro nessas plantas. L. racemosa foi a espécie que mais acumulou ferro em placa e raízes, enquanto A. schaueriana apresentou os níveis mais altos em caules e folhas. A bioacumulação de ferro em placa e raízes de L. racemosa aumentou progressivamente à medida que a concentração de ferro no substrato aumentou. A secreção de ferro por glândulas de sal ocorreu e foi fort... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Metal pollution has long been one of the major environmental problems due to its toxicity, environmental persistence and bioaccumulation. Mangroves are often exposed to these contaminants, and iron is one of the metals present in higher concentrations in sediments and has an important biogeochemical role as regards the precipitation and cycling of metals. We investigate the iron accumulation, distribution and elimination in Avicennia schaueriana Stapf & Leechm. ex Modenke, Laguncularia racemosa (L.) CF Gaertn. and Rhizophora mangle L. exposed to different concentrations of iron. For this study, propagules of all species were collected in field and were cultivated in Hoagland's nutritive medium. After growing, plants were exposed to four treatments by adding 0 (control), 10, 20 and 100 mg L-1 of Fe(II)SO4 to the nutritive medium. Then, plants were collected and chemical, anatomical, histochemical and ultracitochemical analysis were carried out. Part of these analyses was also made in the field for data comparison. The results showed that the Fe-plaque is a place of high iron accumulation in these plants. L. racemosa accumulated the highest amounts of iron in the plaque and roots, while A. schaueriana presented the highest levels in stems and leaves. The bioaccumulation of iron in plaque and roots of L. racemosa increased progressively as the added-iron concentration rose. The iron secretion through salt glands occurred and it was strongly inhibited in L. racemosa at iron concentrations above controls, while A. schaueriana did not show a noticeable drop from controls to the highest added-iron concentration used. In general, L. racemosa presented the lowest translocation factors among the three studied species. With the increase of iron in the substrate, there was a drop in translocation factors between aerial parts and root... (Complete abstract click electronic access below)
Doutor

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Manguezais são ecossistemas costeiros, considerados berçários naturais para muitas espécies de animais. São ambientes que possuem uma acentuada influência das marés. Por se localizarem em regiões costeiras e próximos a indústrias petrolíferas, são alvos constantes de contaminação por petróleo e derivados e se faz necessário estudos sobre técnicas que minimizem os impactos ambientais ocasionados pela presença desses contaminantes. Este trabalho objetivou avaliar técnicas de biorremediação para recuperação ex situ de sedimento de manguezal, através da simulação de contaminação por óleo diesel. Utilizou-se a Rhizophora mangle L. e as linhagens bacterianas CCMICS105 Pseudomonas fluorescens e CCMICS108 Bacillus sp., produtoras de compostos bioativos e promotoras do crescimento de plantas. Os resultados evidenciam que houve redução nos percentuais de n-Alcanos e HPAs de cadeia leves presentes no sedimento, sobretudo nos tratamentos 1 e 2 em que houve a inoculação das bactérias. As bactérias isoladas dos propágulos do Controle 1 e do Tratamento 2 são endofíticas, exceto o isolado 10 que acredita-se ser a mesma bactéria presente no sedimento e na raiz. Todos os isolados do sedimento foram encontrados nas raízes do Tratamento 2, sendo que o isolado 2, que possui características semelhantes à bactéria CCMICS108, esteve em maior densidade. Os dados de MEV e do isolamento indicam que houve colonização das raízes no Tratamento 2 por bactérias semelhantes morfologicamente às linhagens CCMICS105 e CCMICS108. O que contribuiu para o aumento no número de propágulos germinados, para a redução, de modo geral, do espaço intercelular do córtex e da ramificação do sistema central, o que não foi constatado no Tratamento 3. Apesar de não haver diferença significativa nos pesos fresco e seco das plantas nos controles e tratamentos, o Tratamento 2 foi o que apresentou maior biomassa. A Rhizophora mangle L., neste trabalho, não foi eficaz na biodegradação de hidrocarbonetos, possivelmente devido a elevada concentração do óleo diesel (55μg.mL-1) utilizada.
Mangroves are coastal ecosystems, provide nursery habitat for many wildlife species. Are environments that have a marked influence of the tides. Since they are located in coastal areas and near oil industries, mangroves may be a target of contamination by oil and oil products and must be necessary studies of techniques that can minimize environmental impacts caused by the presence of these contaminants. This study aimed to evaluate ex situ bioremediation utilizing techniques simulating contamination by diesel in mangrove sediment. We used the red mangrove Rhizophora mangle L. and bacterial strains Pseudomonas fluorescens (CCMICS105) and Bacillus sp. (CCMICS108), bioactive compounds producing and plant growth promoting bacterias. The results show that there was a decrease in n-alkanes percentage and light chain of PAHs in the sediment, especially in treatments 1 and 2 in which there was inoculation of bacteria. The bacteria isolated from the seedlings from Control 1 and Treatment 2 are endophytic, except isolated 10 that we believe belongs from the sediment and roots. All sediment isolates were found in the roots from Treatment 2, and the isolated 2 shows similar characteristics to CCMICS108 and was higher in density (biomass). The SEM data and from the isolation point to root colonization in Treatment 2 by morphologically similar bacterias CCMICS105 and CCMICS108. Contributing to the increase in the number of seedlings germinated, to reduce, in general, the intercellular space of the cortex and the branch of the central system, which was not observed in Treatment 3. Although there is no significant difference in fresh and dry weights of plants in the control and treatments, the Treatment 2 showed the highest biomass. The Rhizophora mangle L., in this work was not effective to hydrocarbon biodegradating, possibly due to high concentration of diesel used (55μg.mL-1).

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As ilhas de Tinharé e Boipeba, situadas no Litoral Sul, do Estado da Bahia, possuem ricos sistemas e ecossistemas costeiros, em especial importantes áreas de recifes de corais e de manguezais estuarinos e em franja, distribuídos na zona costeira de ambas as ilhas. Estes atributos naturais, associados ao relevante patrimônio sócio-histórico colonial, fizeram destas ilhas importantes destinos turísticos, sendo esta atividade mais consolidada e com maior infra-estrutura na localidade de Morro de São Paulo, em Tinharé. O presente estudo tem como objetivo principal realizar uma análise de espécie de plantas de mangue como bioindicadoras da qualidade ambiental nas ilhas de Tinharé e Boipeba. A região Sul da Bahia, nos últimos anos, tem sido alvo de interesse de diversas empresas petrolíferas, algumas já em atividade de pesquisa e exploração de gás natural e petróleo. Além disso, é comum o trânsito de navios contendo petróleo e/ou os seus derivados nesta região costeira. Na zona costeira das ilhas estudadas foram escolhidas 10 estações de amostragem com características diversas: 04 (quatro) na ilha de Tinharé e 06 (seis) na ilha de Boipeba. Estas estações estão sobre influência direta das ondas e marés, principais agentes hidrodinâmicos costeiros, estando às estações E5, E8, E9, E10 (Boipeba) sob a influência de águas continentais, respectivamente, do Canal dos Patos, rios Catu, Bainema e Santo. Foram coletadas em cada estação 60 folhas de sol, das espécies Rhizophora mangle, Laguncularia racemosa e Avicennia schaueriana, e realizadas análises de parâmetros biométricos e morfologia externa. Estas análises sugeriram redução foliar e alterações na integridade do limbo foliar, principalmente cloroses, pastejo, necroses, perfurações. Após secas até peso constante, estas folhas foram adequadamente preparadas para a determinação de metais pesados (Cu, Cd, Pb e Zn), cuja abertura ocorreu em forno de microondas e a leitura através da espectrometria por absorção atômica com chama, conforme metodologia adotada. Os teores médios de Cu mostraram-se tóxicos para Rhizophora na E2 e para a Laguncularia nas estações E3 e E9. O Chumbo mostrou valores elevados para todas as estações e tóxicos nas estações E3 e E4 (para as três espécies), E2 e E9 (Rhizophora e Avicennia), E5 (Laguncularia e Avicennia), E7 (Avicennia) e E10 (Rhizophora). Neste trabalho, as fontes de impactos ambientais foram variadas e não se conseguiu atribuir a uma única fonte para a contaminação com Chumbo. As informações levantadas não permitiram a identificação de uma fonte principal para a contaminação com o chumbo, pelo contrário, sugere fontes difusas, que se pode inferir a premência de novos estudos e do uso de mais indicadores, por um maior período de tempo. Sugere-se a realização de estudos posteriores que utilizem outros indicadores de contaminantes ambientais, a exemplo da fauna, das águas e sedimentos. Estes poderão complementar as informações apresentadas neste estudo e contribuir a análise mais acurada das fontes de contaminação observadas nas ilhas de Tinharé e Boipeba.
Tinharé and Boipeba islands, located in the southern shore of Bahia, have rich coast and system and ecosystem in special areas of choral reefs e de forest of mangrove, distributed on the coast zone of both islands. These natural attributes, associated to the relevant colonial social historic patrimony, made these islands important tourist destinations, being these activity more consolidated and with a major infrastructure in Morro de São Paulo, in Tinharé. The present study has as principal objective make an analisys about the mangle plant species as bioindicator of the environmental quality in the Tinharé and Boipeba islands. Lately, the Southern Region of Bahia has been the target of interesting to many oil companies, some of them are already working on research and exploration of natural gas and oil. Besides, it is common the transit of ships carrying oil and/or its derivatives in this coast region. In the coast zone of the studied island, 10 sampling stations were chosen with diverse characteristics: 04 in the Tinharé Island and 06 in Boipeba Island. These stations are under direct influence the waves and tides, main hydrodynamic agent of the coast, being stations E5, E8, E9 and E10 (Boipeba) under the influence of the continental Waters, respectively, of Patos Channel, Catu River, Bainema River and Santo River. 60 leaves of sun were collected from the species Rhizophora mangle, Laguncularia racemosa and Avicennia schaueriana and made analisys of biometric parameters and external morphology. These analyses has suggested foliar reduction and alteration in the integrity of the foliar limb, mainly chlorosis, grazing, necrosis and perforations. After dried until constant weigh, these leaves were properly prepared to the determination of heavy metals (Cu, Cd, Pb and Zn), whose opening has ocurred in a microwaves and the reading through spectrometry by atomic absorption with flame, conform adopted methodology. The average content of Cu were toxic to Rhizophora in E2 and to Laguncularia in stations E3 and E9. Lead has showed high level in all stations and toxic in stations E3 and E4 (for all three species), E2 and E9 (Rhizophora and Avicennia), E5 (Laguncularia and Avicennia), E7 (Avicennia) and E10 (Rhizophora). Lead has showed high values for all stations and toxic in stations E3 and E4 (for the three species), E2 and E9 (Rhizophora and Avicennia), E5 (Laguncularia and Avicennia), E7 (Avicennia) and E10 (Rhizophora). In this work, there were various sources of environmental impacts and it was not possible to infer to only one source the contamination with lead. The collected information could not be used in an identification of a principal source of contamination by lead, on the other hand it suggests diffuse sources, what may take us to jump to the conclusion to new studies and the use of more indicators for a longer period of time. It is suggested accomplishment of posterior studies that use other indicators of ambient contaminators, the example of the fauna, waters and sediments. These can complement the information presented in this study and contribute the accurate analysis of the observed sources of contamination in Tinharé Island and Boipeba Island.

This Master's Thesis presents the results of research conducted under the Project ASSESSMENT OF POTENTIAL AS SEQUESTRANT MANGROVE FORESTS CARBON - UFRJ / UFS / UERJ (Case Study of Mangrove Forest River Estuarine Region of San Francisco - Sergipe / Alagoas), with the support of the Erosion and Sedimentation Laboratory, part of the Department of Agricultural Engineering, Federal University of Sergipe. The environmental liabilities created on account of unsustainable use of natural resources over the years has been suppressing and / or degrading a significant portion of mangroves due to the disorderly occupation and exploitation of their areas. Thus, gathering information on vegetation structure becomes a valuable tool for understanding the current state of the same. In this context, the objective of this study was to characterize the floristic, phytosociological structure and litterfall of the mangrove estuary of the river São Francisco, Sergipe. This action will provide a structural description of the community of mangrove trees and shrubs and the factors that promote change in these communities. The results show that the mangrove river São Francisco present a heterogeneous development, presenting higher in the intermediate region of the estuary, where there is less influence of anthropogenic impacts. We recorded species: schaueriana Avicennia, Avicennia germinans, Laguncularia racemosa, Conocarpus erectus and Rhizophora mangle. The average height of forests ranged from 2.88 to 15.63 m, the DBH 3.95 to 19.74 cm, basal area, live from 4.22 to 47.83 m2.ha-1 and density logs Live 375-9100 trunks.ha-1. The annual litter production was 274.43 t.ha-1.year-1 in the first year and 267.92 t.ha-1.year-1 in the second year. Generally, litter production, per compartment, submitted the following descending order: Leaves > Twigs and Branches > Stipules > Fruits and Propagating Material > Miscellaneous > Flowers. Tensors identified in the estuary, the largest impacts are promoting marine erosion and human activities, both promote the removal of large areas.
A presente Dissertação de Mestrado apresenta os resultados da pesquisa realizada no âmbito do Projeto AVALIAÇÃO DO POTENCIAL DE FLORESTAS DE MANGUE COMO SEQUESTRADORAS DE CARBONO UFRJ / UFS / UERJ (Estudo de Caso da Floresta de Mangue da Região Estuarina do rio São Francisco - Sergipe/Alagoas), com o apoio do Laboratório de Erosão e Sedimentação, vinculado ao Departamento de Engenharia Agronômica da Universidade Federal de Sergipe. O passivo ambiental criado por conta do uso não sustentável dos recursos naturais ao longo dos anos vem suprimindo e/ou degradando uma porção significativa de manguezais, principalmente no que diz respeito a ocupação e exploração desordenada de suas áreas. Dessa forma, o levantamento de informações sobre a estrutura da vegetação torna-se uma valiosa ferramenta para o conhecimento do estado atual dos mesmos. Neste contexto, o objetivo deste trabalho foi caracterizar a composição florística, estrutura fitossociológica e produção de serrapilheira do manguezal do estuário do rio São Francisco, Sergipe. Essa ação fornecerá uma descrição estrutural da comunidade arbóreo-arbustiva do manguezal e os fatores que promovem alterações nessas comunidades. Os resultados encontrados revelam que o manguezal do rio São Francisco apresenta desenvolvimento heterogêneo, apresentando-se mais elevado na região intermediária do estuário, onde é menor a influência dos impactos antropogênicos. Foram registradas as espécies: Avicennia schaueriana, Laguncularia racemosa e Rhizophora mangle. A altura média das árvores variou de 2,88 a 15,63 m, o DAP médio de 3,95 a 19,74 cm, a área basal viva de 4,22 a 47,83 m2.ha-1 e a densidade de troncos vivos de 375 a 9100 troncos.ha-1. A produção média anual de serrapilheira foi de 13,53 t.ha-1.ano-1 e 13,21 t.ha-1.ano-1, no primeiro e segundo ano, respectivamente. De modo geral, a produção de serapilheira, por compartimento, apresentou a seguinte ordem decrescente: Folhas > Galhos e Ramos > Estípulas > Frutos e Propágulos > Miscelânea > Flores. Dos tensores identificados no estuário, os que promovem maiores impactos são a erosão marinha e atividades antrópicas, ambos promovem a supressão de grandes áreas.

Orientadores: Anete Pereira de Souza, Maria Imaculada Zucchi
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: O resumo poderá ser visualizado no texto completo da tese digital
Abstract: The complete abstract is available with the full electronic document
Doutorado
Genetica Vegetal e Melhoramento
Doutor em Genetica e Biologia Molecular

Ce travail, centré sur les variations spatio-temporelles des paysages végétaux et morphodynamiques du trait de côte de la région de Port-Gentil, est une contribution à la réflexion sur les problématiques liées aux zones côtières face aux fluctuations futures (changements climatiques, élévation du niveau de la mer). L’objet de cette étude est de tenter, à partir des outils conceptuels (les concepts de paysage et de dynamique) et méthodologiques (relevés de terrain : transects et placettes, des cartes topographiques et de la télédétection : photographies aériennes et images satellitaires), d’une part, d’inventorier et de caractériser les paysages végétaux. D’autre part, nous envisageons comprendre et suivre l’évolution des formations végétales côtières et la vitesse de l’évolution du trait de côte, en localisant les secteurs en accrétion et les secteurs en érosion de la région de Port-Gentil. L’étude de la structure végétale a également permis de mettre en évidence les différentes stratégies de conquête spatiale et les modèles d’occupation de l’espace utilisés par les mangroves et le Melaleuca leucadendron)
This work, centered on the space-time of the vegetable landscapes and morphodynamic variations of the feature of coast of the area of Port-Gentil, is a contribution to the reflexion on the problems related to the coastal zones vis-a-vis on the future fluctuations (climatic changes, rise in the sea level). The object of this study is to try, starting from the conceptual tools (concepts of landscape and dynamics) and methodological (statements of ground: transects and small squares, of the topographic charts and the teledetection: air photographs and satellite images), on the one hand, to inventory and characterize the vegetable landscapes. In addition, we plan to include/understand and follow the evolution of the coastal vegetable formations and the speed of the evolution of the feature of coast, by locating the accretion sectors and the sectors in erosion of the area of Port-Gentil. The study of the vegetable structure also made it possible to highlight the various strategies of space conquest and the models of occupation of space used by the mangroves and Melaleuca leucadendron)

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Never has humanity needed much water to meet their basic needs as today, and water reuse a reality, however, still far from the ideal. Water quality is one of the factors that cause negative effect on growth and development and production of crops. In this context, the objective of this study is to enable the production of white mangrove seedlings (Laguncularia racemosa (L.) Gaertn) using hypersaline waters aiming the reforestation of degraded mangrove areas. For this, there were two experiments; the first trial was conducted between February 13 and June 3, 2014, being installed in a greenhouse located in the land sector belongs to the Federal Rural University of semiarid (UFERSA). The experimental design was a randomized block design with six treatments (S1 = 0,5; S2 = 24; S3 = 53; S4 = 77; S5 = 101e S6 = 124 dS m-1), and four replications, with 24 installments with 15 plants in each plot, a total of 360 plants. Treatments were prepared by diluting hypersaline water coming from the salt crystallisation basin with the water supply network UFERSA in order to obtain electrical conductivity of irrigation water (CEa) to their treatment. The variables were growth, fitomassas, physiological indices, Dickson quality index (DCI) and soil chemical properties. The second experiment was carried out in the field Icapuí-CE municipality, between June 30 and September 9, 2014. In general, all parameters analyzed in experiment I tended to decrease with increasing salt level in the water irrigation. The use of hypersaline water with salinity S3 = 55 dS m-1, is a viable alternative in the production of mangrove seedlings, according to the conditions of this study. The most saline treatment (S6 = 124 dS m-1), promoted the death of most of the plants in the first 100 days after treatment application. The high sodium concentrations in the substrate used not influenced the growth and development of seedlings in the greenhouse period. In the field it was found that the plants irrigated with salinities S3 = 55 dS m-1 and S4 = 77 dS m-1 showed the best grown
Nunca a humanidade necessitou de tanta água para suprir suas necessidades básicas como na atualidade, sendo o reúso de água uma realidade, porém, ainda muito distante do ideal. A qualidade da água é um dos fatores que ocasionam efeito negativo no crescimento e desenvolvimento e produção das culturas. Nesse contexto, objetiva-se com este estudo viabilizar a produção de mudas de Mangue branco (Laguncularia racemosa (L.) Gaertn) com uso de águas hipersalinas visando o reflorestamento de áreas de manguezais degradadas. Para isso, foram realizados dois Experimentos; o experimento I foi conduzido entre 13 de fevereiro e 3 de junho de 2014, sendo instalado em casa de vegetação localizada no setor de solos pertencente à Universidade Federal Rural do Semiárido (UFERSA). O delineamento experimental adotado foi em blocos casualizados, com seis tratamentos (S1 = 0,5; S2 =24; S3 =53; S4 =77; S5 =101e S6 =124 dS m-1),e quatro repetições, sendo 24 parcelas com 15 plantas em cada parcela, totalizando 360 plantas. Os tratamentos foram preparados a partir da diluição de água hipersalina oriunda das bacias de cristalização de sal, com água da rede de abastecimento da UFERSA, de forma a se obter a condutividade elétrica da água de irrigação (CEa) do respectivo tratamento. As variáveis avaliadas foram crescimento, fitomassas, índices fisiológicos, Índice de qualidade de Dickson (IQD) e atributos químicos do solo. O experimento II, foi instalado em campo no município de Icapuí-CE, , entre 30 de junho e 9 de setembro de 2014. De modo geral, todos os parâmetros analisados no experimento I tenderam a diminuir com o aumento do nível salino na água de irrigação. O uso de água hipersalina com salinidade de S3 = 55 dS m-1, é uma alternativa viável na produção de mudas de mangue, de acordo com as condições de realização desse estudo. O tratamento mais salino (S6 = 124 dS m-1), promoveu a morte de grande parte das plantas nos primeiros 100 dias após a aplicação dos tratamentos. As altas concentrações de sódio no substrato utilizado influenciaram o não crescimento e desenvolvimento das mudas no período de casa de vegetação. No campo verificou-se que as plantas irrigadas com as salinidades S3= 55 dS m-1e S4= 77 dS m-1 foram as que melhor cresceram

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Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geoquímica, Niterói, RJ
econômica, têm sido alvo de constantes degradações como desmatamento e aporte de esgoto. Este estudo investigou a biogeoquímica do fósforo (P) em um plantio de Rhizophora mangle numa área de Jardim Gramacho – RJ, onde foram delimitadas três parcelas distintas de 144m², em áreas de plantio realizadas nos anos de 2000 (área JG00), 2002 (área JG02) e 2004 (área JG04). Nestas áreas foram feitas coletas de sedimento; vegetação (raízes subterrâneas, raízes escoras, troncos, galhos e folhas), serrapilheira (folhas, estípulas – tecido que envolve as folhas embrionárias – galhos e partes reprodutivas) e análises de placas de ferro (que são óxidos e hidróxidos de ferro que se depositam na superfície das raízes subterrâneas); para avaliar o comportamento do fósforo em função da proximidade da Baía de Guanabara. Dentro das parcelas, foi caracterizada a estrutura da floresta como: altura, diâmetro na altura do peito (DAP) e a densidade do bosque. Nas três áreas aqui estudadas os bosques apresentaram alturas diferentes em função das suas diferentes idades, porém o DAP e a área basal AB(s) não apresentaram a mesma tendência, devido às muitas ramificações de tronco que as plantas apresentaram. O sedimento da área JG04 esteve mais contaminado por fósforo nas camadas superficiais, se comparado com as áreas JG00 e JG02. Isso provavelmente ocorreu devido ao aporte de resíduos urbanos que atinge as tais camadas. As placas de ferro apresentaram elevados valores de ferro e fósforo em comparação a todos os compartimentos do ambiente aqui estudado. As placas de ferro extraídas de raízes subterrâneas finas apresentaram valores mais elevados se comparados com as placas extraídas de raízes subterrâneas grossas, o mesmo também ocorreu com os tecidos de raízes finas e grossas. Esses resultados provavelmente ocorreram devido à maior área de superfície de contato que as raízes finas apresentam em relação às raízes grossas. Em relação ao total acumulado nas raízes (tecido + placas), as placas apresentaram os maiores percentuais de ferro (75% a 99%) e fósforo (76% a 93%), indicando a importância das placas de ferro como uma barreira geoquímica. A parte lenhosa da vegetação (raízes aéreas, troncos e galhos) apresentou valores de fósforo próximos em relação aos compartimentos do ambiente, isto provavelmente ocorreu por ela exercer funções similares de sustentação. Nesta parte lenhosa da vegetação as três áreas aqui estudadas também apresentaram valores não significativamente diferentes, indicando uma similaridade entre as áreas. Entre os compartimentos da vegetação, as folhas apresentaram os valores de fósforo mais elevados provavelmente devido a sua intensa atividade metabólica. O fluxo de massa de serrapilheira, em um período de um ano, não acompanhou as tendências da pluviosidade ou do vento, mas acompanhou a variação da temperatura que está relacionada com a luminosidade do sol, que influência na taxa fotossintética e, conseqüentemente, na produção de serrapilheira. Isso indica que o fator limitante para a produção de serrapilheira é a temperatura (associada à luminosidade). As concentrações de fósforo na serrapilheira, entre as três áreas, apresentaram valores de fósforo não diferentes significativamente, o mesmo também ocorreu com o fluxo de massa e o fluxo de fósforo nas folhas e estípulas de serrapilheira. No entanto, o fluxo de massa e o fluxo de fósforo nos galhos e partes reprodutivas de serrapilheira apresentaram valores diferentes entre as áreas. Este estudo conclui que, embora as três áreas aqui estudadas apresentem diferentes características nas concentrações de fósforo em todos os compartimentos da serrapilheira, o fluxo de massa e o fluxo de fósforo nas folhas e estípulas de serrapilheira não apresentaram diferenças significativas. Essas similaridades entre os bosques ocorreram devido às compensações que provavelmente ocorreram entre os diferentes fatores que atuam nestes bosques como densidade da vegetação, porte físico dos indivíduos e dinâmica de inundação. As diferenças, entre as três áreas, ocorridas no fluxo de massa e no fluxo de fósforo nos galhos e partes reprodutivas de serrapilheira ocorreram provavelmente devido às diferentes densidades entre os bosques.
Mangroves are highly productive environments and besides its ecological and economic importance, it has been target of constantly damages such as deforestation and sewage discharges. This study investigated the biogeochemistry of phosphorus (P) in an area with Rhizophora mangle situated in Jardim Gramacho – RJ. It was bounded three different plots with 144m² where the species were planted in years 2000 (area JG00), 2002 (area JG02) and 2004 (area JG04). Sediment, vegetation (underground roots, prop roots, trunks, branches and leaves), litter fall (leaves, stipules, branches and reproductive parts) and iron plaques (which are iron oxides and hydroxides that deposit themselves on the underground roots’ surface) were sampled in the areas cited above to study the behavior of phosphorus evaluating Guanabara bay influence. The forest structure parameters such as height, diameter/ breast height (DBH) and wood’s density were studied. The last one showed different heights according to different ages. However the diameter as breast height (DBH) and the trunks’ area (TA) did not show the same trend in spite of many trunks’ ramification presented by the plants. The JG04 sediments showed higher phosphorus concentration in the surface’s layers than JG00 and JG02 sediments. This probably happens in spite of the urban residue discharge in this study area. It was found bigger iron and phosphorus concentration in iron plaques when compared to all the others environment’s compartment concentration values. The iron plaques sampled in thin underground roots presented higher values than the plaques taken of the thick underground roots. The same occurred to the tissues of the thin and thick roots. These results probably happened because of the higher contact surface that the thin roots has in relation of the thick roots. In relation o the total accumulated on the roots (tissue + plaque) the plaques presented the highest percentage of iron (75 to 99%) and phosphorus (76 to 93%) showing the importance of the iron plaques as a geochemical barrier. The woody of part vegetation (prop roots, trunks and branches) presented closer values of phosphorus compared to the environment’s compartment, this probably occurred because they carry out similar duties of support. In this woody part of the vegetation, the three areas studied here also presented not significantly different values showing a similarity between the areas. Between compartments of the vegetation, the leaves presented the highest values of phosphorus probably due its intense metabolic activity. The litter fall weight flow for one year did not follow the rainfall and wind tendencies, but followed the temperature variation which is related to the sun luminosity, which influences in the photosynthetic rate and consequently the litter fall production. This indicates that the limiting factor for the litter fall production is the temperature (related to the luminosity). The concentration of phosphorus in the litter fall among the three areas, presented values of phosphorus not significantly different, the same occurred to the mass flux and flow of phosphorus in the leaves and stipule of litter fall. But, for the mass flow and the phosphorus flow on the branches and reproductive parts of the litter fall presented different values among the areas. This study concludes that although the three areas studied here have different characteristics, the concentration of phosphorus in all the compartments of the litter fall, the mass flux and the flow of phosphorus, in the leaves and the litter fall stipules did not presented significant differences. These similarities between the woods occurred due compensations that probably happened between the different factors that work in these forests as the vegetation density, the physical size of the individuals and the flood dynamics. The difference among the three areas occurred in the mass flux and the flow of phosphorus in the branches and reproductive parts of litter fall occurred probably due different densities between the forests

Os Manguezais são ecossistemas de grande importância ecológica, social e econômica. Tendo em vista que estas áreas vêm sofrendo degradações, em especial a contaminação por resíduos e efluentes contendo metais pesados, que interferem na estabilidade ambiental, torna-se importante identificar o nível de interferências destes contaminantes sobre o desenvolvimento dos bosques que colonizam tais áreas. Assim sendo, a proposta deste estudo é avaliar os efeitos de metais sobre o estabelecimento de propágulos, mudas e indivíduos adultos de Rhizophora mangle (Mangue vermelho), espécie de ampla dispersão em Manguezais, buscando verificar a qualidade ambiental do ecossistema. Foram selecionadas três áreas localizadas nos municípios de Cubatão e São Vicente, na Baixada Santista - SP, grande pólo industrial regional e maior área portuária do país, além de uma área testemunha localizada na Ilha do Cardoso, Cananéia - SP. A Qualidade ambiental, na inexistência de um padrão de concentração de metais em plantas, foi avaliada com base concentração de cinco diferentes metais nos compartimentos solo, água, material vegetal e organismos, comparativamente entre áreas. A pior situação foi constatada para área localizada no Canal da Cosipa, intermediária para o Rio Cascalho e melhor no Manguezal do Rio Mariana. Verificou-se que a contaminação por metais está associada ao padrão do bosque (alterado em função do grau de degradação), sendo este um dos tensores ambientais responsáveis pela reposta negativa no estabelecimento de R. mangle na Baixada Santista.
Mangroves are ecosystems of great ecological and economical importance. Considering that these areas have been degradated, specially by deposition of solid wastes and liquid effluents containing heavy metals it becomes important to identify to what level these contaminants interfere on the development of plants that colonize such environs. Therefore, the aim of this study is assess the effects of heavy metals on the development of “propágulos”, “plântulas” and “mudas” of the Mangue vermelho (Rhizophora mangle), specie which is widely spread on mangroves, in order to determine environmental quality at the mangrove. Three study areas with considerable degradation were selected in the municipalities of Cubatão and São Vicente, in the Baixada Santista - SP, industrial coastal region and greatest sea port of Brazil and a background non – contaminated area located on the Cardoso Island and in Cananéia. Due to the absence of a metal concentration standard for plants, environmental quality was assessed by comparison between five different metals determined in the soil, water, vegetation and organisms at the selected sites. Worst environmental conditions were found at the Cosipa Channel, intermediate at the Cascalho river and best at Mariana river. It was verified that metal concentration was associated with mangrove development (altered as a function of degradation level), being this a cause for the decreased establishment of R.mangle at the Baixada Santista area.

This thesis examines insect leaf herbivory and the insect herbivore community on two common mangrove species – Avicennia marina and Rhizophora stylosa, at two sites near Townsville, northern Queensland. Despite its widely recognised importance in other forested ecosystems, the role of insect herbivory in mangrove ecosystems is often downplayed and remains relatively unexplored. It is generally considered that mangroves lack a diverse and specialised insect herbivore fauna, and are populated with insects from adjoining habitats. It is also commonly believed that mangrove leaves are less palatable and nutritious than leaves of other tree species, and that herbivory levels are less than those found in other forest ecosystems. Sixty-one insect species were confirmed feeding upon A. marina and R. stylosa at the study sites, more than doubling the number of published host records for Australian mangroves. Herbivore diversity on the two mangrove species was similar, but only four of the 61 herbivore species were in common between them and the composition of the two faunas was substantially different. The two faunas show a high degree of host-specificity and adaptation to their mangrove hosts and there were substantial similarities between the faunas found in this study and those of other Avicennia and Rhizophora species elsewhere in the world. The diversity of folivores on these two mangrove species was similar to that of other nearby non-mangrove trees and to that reported for other trees elsewhere in the tropics. Nearly all mangrove herbivory studies have measured damage on discrete leaf samples collected at one point in time. This approach fails to detect entirely consumed leaves, or partly damaged leaves that have been abscised. These leaves can be accounted for by an alternative long-term method that makes repeated herbivory estimates on tagged leaves. Application of the long-term method in this study found herbivory to be 3-6 times higher than estimated by discrete measurements. R. stylosa had only 2-3% loss of leaf area in discrete samples but 7-13% loss in the long-term study. A. marina had 6-7% loss of leaf area in discrete samples but 28-36% loss in the long-term study. For both species, most herbivory occurred whilst the leaves were young. Once past the juvenile phase, R. stylosa leaves were rarely attacked. In contrast, mature A. marina leaves suffered significant insect damage and leaf loss. Herbivory reduced average leaf longevity of all leaves by 4-5% for R. stylosa and 12-13% for A. marina. In mangroves, loss of entire leaves is reported to be rare, but in R. stylosa and A. marina in this study, 4-5% and 19-29% of leaves, respectively, were either entirely consumed, or aborted due to insect damage. For both species, loss of leaf material through premature abscission of damaged leaves was as great as that actually consumed by insects, indicating a role for herbivory in promoting leaf fall. Destruction of developing leaf buds by insects resulted in greater leaf losses than that suffered by emerged leaves. This was especially important for R. stylosa, which can only produce leaves from the apical bud. Damage to R. stylosa apical buds was common, frequently resulting in the loss of leaves before they emerged or, where damage resulted in the destruction of the apical bud, cessation of leaf production and death of that shoot. In some cases, new apical buds regenerated from suppressed lateral buds immediately below the destroyed apical bud. Death of existing shoots and regeneration from suppressed laterals are potentially major sources of architectural change to tree growth form. Damage to apical buds also resulted in the loss of developing inflorescences and lateral branches. The chemical and physical nature of leaves changed significantly as they aged. Young leaves had a higher nutrient and chlorophyll concentration, but lower leaf thickness and leaf mass per unit area. Thus they were more nutritious and less tough for herbivores. These young leaves were especially prone to premature leaf fall because of insect damage. Leaves re-translocated over half of their nutrients prior to senescence but consumption or premature abscission of leaves before this process is complete may increase nutrient loss from the trees to microbial and detrital food chains on the forest floor. Thus herbivore-mediated leaf fall may also impact upon nutrient dynamics in mangrove forests. This thesis demonstrates that: mangroves support a diverse and distinctive insect herbivore community; leaf herbivory is much higher than previously reported; there are additional mechanisms (eg, apical bud damage) by which herbivores affect leaf loss and other aspects of tree performance; and insects significantly affect leaf longevity, the timing of leaf fall and the quality of leaf litter. These results indicate that the role of herbivorous insects in mangrove ecosystems is more important than previously thought and that its evaluation needs to go well beyond simple static measures of leaf area missing from mature leaves.

This thesis examines insect leaf herbivory and the insect herbivore community on two common mangrove species – Avicennia marina and Rhizophora stylosa, at two sites near Townsville, northern Queensland. Despite its widely recognised importance in other forested ecosystems, the role of insect herbivory in mangrove ecosystems is often downplayed and remains relatively unexplored. It is generally considered that mangroves lack a diverse and specialised insect herbivore fauna, and are populated with insects from adjoining habitats. It is also commonly believed that mangrove leaves are less palatable and nutritious than leaves of other tree species, and that herbivory levels are less than those found in other forest ecosystems. Sixty-one insect species were confirmed feeding upon A. marina and R. stylosa at the study sites, more than doubling the number of published host records for Australian mangroves. Herbivore diversity on the two mangrove species was similar, but only four of the 61 herbivore species were in common between them and the composition of the two faunas was substantially different. The two faunas show a high degree of host-specificity and adaptation to their mangrove hosts and there were substantial similarities between the faunas found in this study and those of other Avicennia and Rhizophora species elsewhere in the world. The diversity of folivores on these two mangrove species was similar to that of other nearby non-mangrove trees and to that reported for other trees elsewhere in the tropics. Nearly all mangrove herbivory studies have measured damage on discrete leaf samples collected at one point in time. This approach fails to detect entirely consumed leaves, or partly damaged leaves that have been abscised. These leaves can be accounted for by an alternative long-term method that makes repeated herbivory estimates on tagged leaves. Application of the long-term method in this study found herbivory to be 3-6 times higher than estimated by discrete measurements. R. stylosa had only 2-3% loss of leaf area in discrete samples but 7-13% loss in the long-term study. A. marina had 6-7% loss of leaf area in discrete samples but 28-36% loss in the long-term study. For both species, most herbivory occurred whilst the leaves were young. Once past the juvenile phase, R. stylosa leaves were rarely attacked. In contrast, mature A. marina leaves suffered significant insect damage and leaf loss. Herbivory reduced average leaf longevity of all leaves by 4-5% for R. stylosa and 12-13% for A. marina. In mangroves, loss of entire leaves is reported to be rare, but in R. stylosa and A. marina in this study, 4-5% and 19-29% of leaves, respectively, were either entirely consumed, or aborted due to insect damage. For both species, loss of leaf material through premature abscission of damaged leaves was as great as that actually consumed by insects, indicating a role for herbivory in promoting leaf fall. Destruction of developing leaf buds by insects resulted in greater leaf losses than that suffered by emerged leaves. This was especially important for R. stylosa, which can only produce leaves from the apical bud. Damage to R. stylosa apical buds was common, frequently resulting in the loss of leaves before they emerged or, where damage resulted in the destruction of the apical bud, cessation of leaf production and death of that shoot. In some cases, new apical buds regenerated from suppressed lateral buds immediately below the destroyed apical bud. Death of existing shoots and regeneration from suppressed laterals are potentially major sources of architectural change to tree growth form. Damage to apical buds also resulted in the loss of developing inflorescences and lateral branches. The chemical and physical nature of leaves changed significantly as they aged. Young leaves had a higher nutrient and chlorophyll concentration, but lower leaf thickness and leaf mass per unit area. Thus they were more nutritious and less tough for herbivores. These young leaves were especially prone to premature leaf fall because of insect damage. Leaves re-translocated over half of their nutrients prior to senescence but consumption or premature abscission of leaves before this process is complete may increase nutrient loss from the trees to microbial and detrital food chains on the forest floor. Thus herbivore-mediated leaf fall may also impact upon nutrient dynamics in mangrove forests. This thesis demonstrates that: mangroves support a diverse and distinctive insect herbivore community; leaf herbivory is much higher than previously reported; there are additional mechanisms (eg, apical bud damage) by which herbivores affect leaf loss and other aspects of tree performance; and insects significantly affect leaf longevity, the timing of leaf fall and the quality of leaf litter. These results indicate that the role of herbivorous insects in mangrove ecosystems is more important than previously thought and that its evaluation needs to go well beyond simple static measures of leaf area missing from mature leaves.

Thesis (Ph. D.)--Florida State University, 2005.
Advisor: Dr. Jon Anthony Stallins, Florida State University, College of Social Sciences, Dept. of Geography. Title and description from dissertation home page (June 15, 2005). Document formatted into pages; contains xiii, 169 pages. Includes bibliographical references.

生長於潮間帶的紅樹林是熱帶和亞熱帶地區最具生產力的生態系統之一。香港擁有十個紅樹品種，其覆蓋面積約共三百五十公頃。位於香港西北面的米埔是現時香港最大的紅樹林區。這片紅樹林及其鄰近濕地於一九九五年被列為拉姆薩爾重要的濕地。隨著經濟的迅速發展、污染及一些不可持續的開發，全球紅樹林的面積不斷地萎縮。而香港的紅樹也正面對城市發展及基建的直接威脅。因此，了解及監測紅樹林的生長狀況、覆蓋面積的轉變是紅樹林保育的基礎。遙感是具有成本效益和能提供及時數據的技術，在紅樹林的生態保育及監測上發揮著重要功能。
是次研究選擇位於米埔的紅樹林區。通過結合高光譜和雷達數據以及實地磡測，以達到三個目的。第一，利用模式辨認分析找出可提高品種辨識度的光譜帶及雷達數據。第二，把挑選出來的光譜帶及雷達數據組合，利用不同的分類法包括最大概似法、决策樹 C5.0演算法、類神經網路及支持向量機進行紅樹林的品種分類，並籍此測試各分類法的精度。第三，利用植被指數及雷達數據中取得的參數為獨立變量，而在野外點測的葉面積指數 (LAI) 為因變量，通過迴歸分析以估算整片紅樹林的葉面積指數，籍此了解紅樹林現時的生物物理狀況。
根據特徵選擇的結果，位於高光譜數據中的綠波段 (570nm, 580nm, 591nm及601nm)、紅波段 (702nm)、紅邊位 (713nm)、近紅外波段 (764nm及774nm)、 短波紅外波段 (1276nm, 1316nm及1629nm) 以及在不同季節取得的過濾後向散射數據是最能辨識品種差異。
據品種分類的結果顯示，單用多時後向散射特徵數據存在很大誤差。而在大多的情況下，單用光譜數據比起混合光譜及後向散射數據的分類表現為佳。但對於某些品種來說，後向散射數據能給予比較準確的預測。另外，在同數據組合下，分類法在訓練精度上沒有多大的分別。除了類神經網路分類法以外，其他分類法的測試精度總比其訓練精度低。這說明類神經網路模型比起其他分類法的模型要為穩定，而决策樹模型則被過度訓練。根據生產者及使用者精度分析，因為缺乏足夠的訓練樣本，桐花樹及海桑屬的精度較其他品種為低。
據不同植被指數的簡單線性迴歸模型顯示，利用三角植被指數 (TVI)及修正葉綠素吸納比例指數一 (MCARI 1) 對於葉面積指數的估算是最準確。相反地，葉面積指數與從雷達數據中取得的參數關係則比較弱。這表示單用雷達參數不能對葉面積指數進行準確的估算。在結合植被指數及雷達參數的多元逐步迴歸分析下，三角植被指數及在灰度共生矩陣下得出的角二階矩參數能減低葉面積指數估算的誤差。總結以上兩項分析，光譜及雷達數據在紅樹林的品種分類及葉面積指數估算上有互補的作用。
Mangrove is one of the most productive ecosystems flourished in the intertidal zone of tropical and subtropical regions. Hong Kong has ten true mangrove species covering an approximate area of 350 hectares. Mai Po locating in the northwestern part of Hong Kong nourishes the largest mangrove stand and it was listed as a Wetland of Importance under the Ramsar Convention in 1995. Over the years, areas of mangrove have been shrinking globally due to development, pollution, and other unsustainable exploitation and Hong Kong was no exception. In Hong Kong, mangroves are usually sacrificed for urban development and infrastructure construction. Therefore, it is crucial to monitor their growth conditions, change of extent and possible unsustainable practices threatening their existence. Remote sensing being a cost-effective and timely tool for vegetation conservation is most suitable for such purpose.
Taking Mai Po as study area, this study acquired satellite-borne hyperspectral and radar data supplemented with in situ field survey to achieve three purposes. First, features from the remotely-sensed data that are significant to species discrimination were identified through pattern recognition. Second, selected features grouped into different subsets were used to delineate the boundary of mangrove species through supervised classification. In the meantime, classifiers including maximum likelihood (ML), decision tree C5.0 (DT), artificial neural network (ANN) and support vector machines (SVM) were tested for their accuracy performance. The third purpose is to understand the current biophysical condition of mangrove through leaf area index (LAI) modeling by regressing field-measured LAI against vegetation indices, backscatter and textural measures.
Results from feature selection revealed that hyperspectral narrowbands locating in green at 570nm, 580nm, 591nm, 601nm; red at 702nm; red-edge at 713nm; near infrared at 764nm and 774nm and shortwave infrared at 1276nm, 1316nm and 1629nm as well as the multi-temporal filtered backscatter captured in different seasons have high sensitivity to species difference.
Species-based classification using multi-temporal backscatter features alone do not provide a satisfactory accuracy. Comparatively, results from pure spectral bands have better overall accuracy than that from combining spectral and radar features. However, radar backscatter does improve accuracy of some species. Besides, all classifiers had similar variations of training accuracy under the same feature subset. However, the testing accuracy is much lower with the exception of ANN. Performance of ANN was more stable and robust than other classifiers while serious overtraining occurs for the DT classifier. Moreover, most species were mapped accurately as revealed by the producer’s and user’s accuracy with the exception of A. corniculatum and Sonneratia spp. due to deficiency of training samples.
Simple linear regression model with VIs revealed that triangular vegetation index (TVI) and modified chlorophyll absorption ratio index 1 (MCARI1) had the best relationship with LAI. However, weak relationship was found between field- measured LAI and radar parameters suggesting that radar parameters cannot be used as single predictor for LAI. Results from stepwise multiple regression suggested that TVI combined with GLCM-derived angular second moment (ASM) can reduce the estimation error of LAI. To conclude, the study has demonstrated spectral and radar data are complementarity for accurate species discrimination and LAI mapping.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Wong, Kwan Kit.
Thesis (Ph.D.)--Chinese University of Hong Kong, 2012.
Includes bibliographical references (leaves 434-472).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstract also in Chinese.
ACKNOWLEDGEMENTS --- p.II
ABSTRACT --- p.IV
論文摘要 --- p.VI
TABLE OF CONTENTS --- p.VIII
LIST OF ABBREVIATIONS --- p.XIII
LIST OF TABLES --- p.XV
LIST OF FIGURES --- p.XVIII
Chapter CHAPTER 1 --- INTRODUCTION --- p.1
Chapter 1.1 --- BACKGROUND TO THE STUDY --- p.1
Chapter 1.1.1 --- Mangrove Mapping and Monitoring --- p.1
Chapter 1.1.2 --- Mangrove Mapping and Monitoring --- p.3
Chapter 1.1.3 --- Role of Remote Sensing in Mangrove Study --- p.4
Chapter 1.2 --- OBJECTIVES OF THE STUDY --- p.6
Chapter 1.3 --- SIGNIFICANCE OF THE STUDY --- p.7
Chapter 1.4 --- ORGANIZATION OF THE THESIS --- p.8
Chapter CHAPTER 2 --- LITERATURE REVIEW --- p.10
Chapter 2.1 --- INTRODUCTION --- p.10
Chapter 2.2 --- FACTORS AFFECTING VEGETATION REFLECTANCE --- p.11
Chapter 2.2.1 --- Foliar structure and principal constituents --- p.12
Chapter 2.2.2 --- Foliar optical properties --- p.14
Chapter 2.2.2.1 --- The visible region (400-700nm) --- p.14
Chapter 2.2.2.2 --- The red edge (690-740nm) --- p.15
Chapter 2.2.2.3 --- The near-infrared region (700-1300nm) --- p.16
Chapter 2.2.2.4 --- The short-wave infrared region (1300-2500nm) --- p.17
Chapter 2.2.3 --- Canopy architecture --- p.18
Chapter 2.2.4 --- Background reflectance --- p.19
Chapter 2.2.5 --- Atmospheric perturbation --- p.20
Chapter 2.2.6 --- Sun-sensor relationship --- p.22
Chapter 2.3 --- HYPERSPECTRAL IMAGING AND VEGETATION CLASSIFICATION --- p.23
Chapter 2.4 --- RADAR IMAGING AND VEGETATION CLASSIFICATION --- p.31
Chapter 2.5 --- PATTERN RECOGNITION FOR VEGETATION CLASSIFICATION --- p.39
Chapter 2.5.1 --- The Hughes Phenomenon and Dimensionality Reduction --- p.39
Chapter 2.5.2 --- Statistical Pattern Recognition and Feature Selection --- p.44
Chapter 2.5.2.1 --- Search Method --- p.47
Chapter 2.5.2.1.1 --- Exhaustive search --- p.48
Chapter 2.5.2.1.2 --- Branch and bound --- p.49
Chapter 2.5.2.1.3 --- Sequential forward/ backward selection --- p.55
Chapter 2.5.2.1.4 --- Sequential Floating search --- p.57
Chapter 2.5.2.1.5 --- Oscillating Search --- p.61
Chapter 2.5.2.1.6 --- Genetic algorithm --- p.64
Chapter 2.5.2.2 --- Evaluation criteria --- p.66
Chapter 2.5.2.2.1 --- Distance measure --- p.67
Chapter 2.5.2.2.2 --- Information measure --- p.68
Chapter 2.5.2.2.3 --- Classification error --- p.71
Chapter 2.5.2.3 --- Feature Selection Stability --- p.72
Chapter 2.5.3 --- Feature extraction --- p.75
Chapter 2.6 --- BIOPHYSICAL PARAMETERS MEASUREMENT AND ESTIMATION --- p.77
Chapter 2.6.1 --- Leaf Area Index (LAI) --- p.78
Chapter 2.6.2 --- Fraction of Absorbed Photosynthetically Active Radiation (fAPAR) --- p.79
Chapter 2.6.3 --- In-situ Leaf Area Index Measurement --- p.81
Chapter 2.6.3.1 --- Direct and Indirect Methods --- p.81
Chapter 2.6.3.2 --- LAI Estimation through Gap Fraction Inversion --- p.85
Chapter 2.6.3.3 --- Gap Fraction Ground Measurement --- p.89
Chapter 2.6.3.3.1 --- LAI-2000 Plant Canopy Analyzer --- p.89
Chapter 2.6.3.3.2 --- Hemispherical Photography --- p.92
Chapter 2.6.3.4 --- Correction of Indirect LAI Measurement --- p.99
Chapter 2.6.3.4.1 --- Clumping --- p.100
Chapter 2.6.3.4.2 --- Mixture of Green and Non-green Elements --- p.101
Chapter 2.6.4 --- Empirical Relationship with Spectral Vegetation Indices --- p.102
Chapter 2.6.4.1 --- Traditional Vegetation Indices --- p.103
Chapter 2.6.4.2 --- Leaf Area Index Estimation from Hyperspectral and Radar Images --- p.106
Chapter 2.6.5 --- Physically-based Canopy Reflectance Model Inversion --- p.111
Chapter 2.6.5.1 --- Canopy Reflectance Model --- p.111
Chapter 2.6.5.2 --- Model Inversion and Biophysical Parameters Extraction --- p.115
Chapter 2.7 --- SUMMARY --- p.118
Chapter CHAPTER 3 --- METHODOLOGY --- p.120
Chapter 3.1 --- INTRODUCTION --- p.120
Chapter 3.2 --- STUDY AREA DESCRIPTION --- p.120
Chapter 3.3 --- METHODOLOGICAL FLOW --- p.124
Chapter 3.4 --- REMOTE SENSING DATA ACQUISITION AND PROCESSING --- p.127
Chapter 3.4.1 --- Hyperion - EO-1 --- p.127
Chapter 3.4.1.1 --- Radiometric correction --- p.127
Chapter 3.4.1.1.1 --- Vertical strips removal --- p.128
Chapter 3.4.1.1.2 --- Atmospheric correction --- p.129
Chapter 3.4.1.1.3 --- Wavelength recalibration --- p.135
Chapter 3.4.1.1.4 --- SNR enhancement through MNF --- p.137
Chapter 3.4.1.2 --- Geometric correction --- p.139
Chapter 3.4.1.3 --- Atmospheric correction algorithms comparison --- p.140
Chapter 3.4.2 --- ASAR - ENVISAT --- p.141
Chapter 3.4.2.1 --- Data Acquisition --- p.141
Chapter 3.4.2.2 --- Data Processing --- p.143
Chapter 3.4.2.2.1 --- Radiometric and Geometric Correction --- p.145
Chapter 3.4.2.2.2 --- Speckle Filtering --- p.146
Chapter 3.5 --- FIELD MEASUREMENTS AND DATA PROCESSING --- p.149
Chapter 3.5.1 --- Species Distribution --- p.149
Chapter 3.5.2 --- Leaf Spectra Measurement --- p.151
Chapter 3.5.2.1 --- Leaf Collection and Handling --- p.152
Chapter 3.5.2.2 --- ASD FieldSpec 3 Setup --- p.154
Chapter 3.5.2.3 --- Laboratory setup --- p.156
Chapter 3.5.2.4 --- Spectra Measurement --- p.158
Chapter 3.5.2.5 --- Spectral similarity and variability --- p.159
Chapter 3.5.3 --- In situ Leaf Area Index Measurement --- p.161
Chapter 3.5.3.1 --- The optical instrument --- p.161
Chapter 3.5.3.2 --- The LAI survey campaign p163
Chapter 3.5.3.3 --- Data processing and canopy analysis --- p.166
Chapter 3.5.3.4 --- Canopy parameter computation gap fraction, LAI, clumping index, mean inclination angle --- p.170
Chapter 3.5.3.5 --- Field LAI and Their Correlation with Reflectance and Backscattering Coefficient Data Exploration --- p.175
Chapter 3.6 --- FEATURE SELECTION --- p.175
Chapter 3.6.1 --- Data Preprocessing and Preparation --- p.178
Chapter 3.6.2 --- Data Format and Split --- p.183
Chapter 3.6.3 --- Wrapper-based Approach --- p.185
Chapter 3.6.4 --- Search Algorithm --- p.187
Chapter 3.6.5 --- Stability Evaluation --- p.187
Chapter 3.6.6 --- Feature Frequency analysis --- p.188
Chapter 3.7 --- MANGROVE SPECIES CLASSIFICATION --- p.189
Chapter 3.7.1 --- Species Separability --- p.193
Chapter 3.7.2 --- Gaussian Maximum Likelihood Classifier --- p.193
Chapter 3.7.3 --- Decision Tree Classifier --- p.194
Chapter 3.7.4 --- Artificial Neural Network Classifier --- p.197
Chapter 3.7.5 --- Support Vector Machines Classifier --- p.199
Chapter 3.7.6 --- Accuracy Assessment --- p.204
Chapter 3.8 --- LEAF AREA INDEX MODELING --- p.206
Chapter 3.8.1 --- Preliminary Exploration of Relationship between Hyperspectral bands and LAI --- p.206
Chapter 3.8.2 --- Vegetation Index Derived from Hyperspectral Data. --- p.206
Chapter 3.8.3 --- Radar Backscatter and Derived Textural Parameters --- p.208
Chapter 3.8.4 --- Regression Analysis --- p.211
Chapter 3.8.5 --- Error Estimation --- p.217
Chapter 3.9 --- SUMMARY --- p.218
Chapter CHAPTER 4 --- RESULTS AND DISCUSSION (I) FEATURE SELECTION AND MANGROVE SPECIES CLASSIFICATION --- p.221
Chapter 4.1 --- INTRODUCTION --- p.221
Chapter 4.2 --- DATA PROCESSING AND EXPLORATION --- p.221
Chapter 4.2.1 --- Atmospheric correction algorithms comparison --- p.222
Chapter 4.2.2 --- Radar Data Speckle Reduction --- p.227
Chapter 4.2.3 --- Statistical Discrimination of Mangrove Spectral Class --- p.230
Chapter 4.3 --- FEATURE SELECTION --- p.249
Chapter 4.3.1 --- Sequential Forward Selection (SFS) --- p.250
Chapter 4.3.2 --- Sequential Floating Forward Selection (SFFS). --- p.256
Chapter 4.3.3 --- Oscillating Search (OS) --- p.262
Chapter 4.3.4 --- Search Algorithms comparison --- p.268
Chapter 4.3.5 --- Final Subset Selection --- p.270
Chapter 4.3.6 --- Correlation Analysis --- p.280
Chapter 4.4 --- IMAGE CLASSIFICATION --- p.283
Chapter 4.4.1 --- Mangrove Spectral Class Separability --- p.284
Chapter 4.4.2 --- Gaussian Maximum Likelihood (ML) --- p.288
Chapter 4.4.3 --- Decision Tree (DT) --- p.297
Chapter 4.4.4 --- Artificial Neural Network (ANN) --- p.304
Chapter 4.4.5 --- Support Vector Machines (SVM) --- p.312
Chapter 4.4.6 --- Algorithm Comparison --- p.321
Chapter 4.5 --- DISCUSSION AND IMPLICATION --- p.325
Chapter 4.5.1 --- Feature Selection --- p.325
Chapter 4.5.2 --- Mangrove Classification --- p.342
Chapter 4.6 --- SUMMARY --- p.351
Chapter CHAPTER 5 --- RESULTS AND DISCUSSION (II) - LEAF AREA INDEX MODELING --- p.353
Chapter 5.1 --- INTRODUCTION --- p.353
Chapter 5.2 --- DATA EXPLORATION --- p.353
Chapter 5.2.1 --- Dependent Variable: Field measured LAI --- p.353
Chapter 5.2.2 --- Independent Variables: Vegetation Index and texture measure --- p.355
Chapter 5.2.3 --- Hyperspectral bands and LAI --- p.356
Chapter 5.2.4 --- Normality testing --- p.359
Chapter 5.2.5 --- Linearity testing --- p.363
Chapter 5.2.6 --- Outliner detection --- p.365
Chapter 5.3 --- SIMPLE LINEAR REGRESSION ANALYSIS --- p.366
Chapter 5.3.1 --- LAI2000 Generalized method --- p.369
Chapter 5.4 --- STEPWISE MULTIPLE REGRESSION ANALYSIS --- p.381
Chapter 5.4.1 --- LAI2000 Generalized method --- p.384
Chapter 5.5 --- DISCUSSION AND IMPLICATION --- p.391
Chapter 5.5.1 --- LAI model comparison --- p.391
Chapter 5.5.2 --- Species composition and LAI --- p.393
Chapter 5.5.3 --- Hyperspectral Bands, Vegetation Indices and LAI --- p.397
Chapter 5.5.4 --- Backscatter, texture measures and LAI --- p.407
Chapter 5.5.5 --- Complementarity of Vegetation Index and Radar Parameters --- p.414
Chapter 5.6 --- SUMMARY --- p.421
Chapter CHAPTER 6 --- CONCLUSION --- p.423
Chapter 6.1 --- SUMMARY OF THE STUDY --- p.423
Chapter 6.2 --- LIMITATION OF THE STUDY --- p.427
Chapter 6.3 --- RECOMMENDATION --- p.431
Chapter REFERENCE --- p.434
Chapter APPENDIX A --- GEOMETRIC CORRECTION OF HYPERSPECTRAL DATA --- p.473
Chapter APPENDIX B --- SCRIPTS DERIVED FROM FEATURE SELECTION TOOLBOX (FST) FOR FEATURE SELECTION --- p.475
Chapter APPENDIX C --- PREDICTED LAI(BON) AND LAI(2000) FROM SIMPLE LINEAR REGRESSION MODELS --- p.513
Chapter APPENDIX D --- PREDICTED LAI(BON) AND LAI(2000) FROM MULTIPLE STEPWISE REGRESSION MODELS --- p.524

碩士
崑山科技大學
環境工程研究所
101
In this study, mangrove plants and aquatic plants diluted and purified the effluent of industrial sewage treatment plant. According to the results of the laboratory cultivation, the highest salt storage of the plant was different. The salt accumulation of the Avicennia was 71.3 mg per gram with 50‰ ambient salinity. That of the Rhizophora was 67.9 mg with 25‰ ambient salinity. That of the Kandelia was 52.1 mg with 25‰ ambient salinity. That of the Lumnitzera was 46.8 mg per gram with 35‰ ambient salinity. And the salt accumulation of the Canna was 30.6 mg per gram with 20‰ salinity. Close to the ambient salinity of the ecological pool (7-10‰), the salt accumulation of per gram dry weight of the Avicennia, the Rhizophora, the Kandelia, the Canna, the Lumnitzera sequenced to 46 mg, 32.5 mg, 27.8 mg, 22.6 mg, 21.1 mg. About the salt tolerability of the plant, Kandelia and Canna only resistanced to 30‰ and 20‰ ambient salinity, Rhizophora was at least up to 45%, Avicennia and Lumnitzera were at least up to 50‰. The salt accumulation in various parts of the plant under test was mostly in the leaves. We could see the mangrove plants and aquatic plants in order to remove too much salt falling by the old leaves, and it could dilute the salinity of the water. According to the results of the ecological pool cultivation, the salinity of the water was about to maintain 7%. The interval between the first and the second detection time was 6 months, and the salt accumulation of per gram dry weight in the plant was 13.3-37.7 mg of Avicennia, 17.4-26.8 mg of Rhizophora, 6.4-17.1 mg of Lumnitzera, 10.6-14.9 mg of Canna, 15.7-20.3 mg of Typha angustifolia, 17.1-20.6 mg of The umbrella round of sedge. Under the same ambient salinity, with the increase of growth time, the salt accumulation of the plants did not continue to increase, while showing the amount of saturation. While the ambient salinity increased, the salt of the stems of Avicennia, Kandelia, Lumnitzera, and Canna increased the smallest, the salt of the leaves increased the largest. When per unit increased in salinity (‰) , per gram dry weight of the salt of the stem increased to 0.27-0.97 mg, per gram dry weight of the leaf increased to 1.34-3.71 mg, per gram dry weight of the root increased to 0.51 -1.28 mg. The per gram dry weight of the root, the stem, the leaf of Rhizophora was 4.02 mg,1.91 mg, 0.45 mg. The average nitrogen content of the whole plant of Avicennia was 1.59%, Rhizophora was 0.79%, Lumnitzera was 0.69%, Canna was 2.60%, Typha angustifolia was 1.61%, The umbrella round of sedge was 2.71%；The average phosphorus content of the whole plant of Avicennia was 0.04%, Rhizophora was 0.06%, Lumnitzera was 0.04%, Canna was 0.09%, Typha angustifolia was 0.10%, The umbrella round of sedge is 0.09%. Among the three mangrove, the highest nitrogen content was 1.59% of Avicennia, the highest phosphorus content was 0.06% of Rhizophora. The highest nitrogen content of all the measured plants was 2.71% of the umbrella round of sedge and the highest phosphorus content was 0.10% of Typha angustifolia. About the oxidized drainage of the ecological pool, the ammonium nitrogen removal rate was 3.0%, the nitrate nitrogen removal rate was 0.8%. It is not significant to the nitrogen removal performance. The phosphate removal rate was 4.7%, and the effect of phosphorus removal was not significant.The Zinc removal rate of approximately was 0.7%.

An assessment was made of American Samoa mangroves' vulnerability and predicted changes in position from sea-level rise. The study also evaluated capacity in the Pacific Islands region to assess mangrove vulnerability to climate change and institute adaptation measures. Of the outcomes from climate change, relative sea-level rise may be the greatest threat to mangroves. By 2100, mangrove losses from relative sea-level rise could be as high as 47 percent in American Samoa and 22 percent when extrapolating regionally, causing about a quarter of total predicted annual regional losses. American Samoa mangrove vulnerability to sea-level rise was determined and future position was predicted through analyses of sea-level trends and projections, mangrove spatial change analysis, reconstruction and monitoring of sedimentation rates, and determination of potential migration areas. These analyses provided three categories of requisite information: (i) Observed and projected rate of change in sea-level relative to the mangrove sediment surface, determined from trends in relative sea-level through analysis of sea-level data from a local tide gauge and observations of trends in the elevation of mangrove sediment surfaces; (ii) observed and projected trends in mangrove seaward margin positions; and (iii) physiographic settings (slope of land upslope and location of obstacles along the landward margin). Results indicate that American Samoa mangroves are not likely keeping pace with rising sea-level, both surface and subsurface process controls on sediment elevation are important factors, and a large proportion (16, 23 and 68 percent) of the landward margins of the three mangrove study sites are obstructed from natural landward migration with sea-level rise. Based on observed trends in sediment surface elevations and movement of two mangroves' seaward margins, these sites have likely not been keeping pace with relative sea-level rise, with an elevation deficit of about 2 mm eat both sites. An embayment mangrove experienced sea-level rise relative to the mangrove sediment surface of 2.22 (± 2.22 95% Cl) mm a-1 and a basin mangrove experienced 1.97 (± 0.32 95% Cl) mm a -1 . At these sites, a highly significant positive correlation between the change in position of the seaward margins and change in relative sea-level suggests that rising sea-level relative to the mangrove surface caused the observed landward migration. Shoreline movement was not significantly correlated with changing sea-level at a third site, where development activities have likely been dominant factors determining changes in mangrove position; vulnerability, based on observations of trends in sediment surface elevation, was not determined for this third site. This study was the first to employ broad spatial coverage and a large number of sampling locations (330 sampling locations) to observe trends in the elevation of two mangroves' sediment surfaces, a necessary sampling design to adequately characterize mangrove sites, based upon previously documented high spatial variability in trends in mangroves' surface elevation. Both surface and subsurface processes exhibited large controls on sediment elevation, highlighting the need to monitor the full soil profile to accurately measure trends in mangrove surface elevation. Highly significant different mean changes in sediment surface elevation occurred for mangroves in different geomorphic settings (a difference of 3.4 [± 1.3 SE] mm a -1 , N = 1412, P<0.007), supporting the hypothesis that mangroves in an estuarine/drowned river valley composite geomorphic setting are more resistant to relative sea-level rise than embayment mangroves. Mean landward migration of the mangroves' seaward margins was 12 to 37 times the relative sea-level rise rate. This is the first documentation of significantly different mean sediment surface elevation change for mangroves in different geomorphic settings, and the first documentation of the relationship between the rate of seaward mangrove margin erosion and relative sea-level rise rate, information needed to develop reliable predictive elevation models for mangrove ecosystems. Changes in extreme high water levels and frequency were found to not pose an increasing threat to American Samoa mangroves beyond the effects from rising mean sea-level. This site-specific assessment supports the hypothesis that, in this region, which experiences large El Nino Southern Oscillation-related steric changes lasting several months to years, extreme high waters are likely to be related to mean sea-levels. This was the first comprehensive assessment to determine both (i) whether the mangrove site's threshold for resistance to sea-level rise has been exceeded, and (ii) the site's capacity to naturally migrate landward in response to rising sea-level. This was the first study to select research methods suitable for employment in Pacific Small Island Developing States, considering both cost and staff abilities. Results support instituting adaptation measures in American Samoa to reduce obstacles to landward mangrove migration with sea-level rise and to manage activities within catchments that affect mangrove elevation. Regionally, there is extremely low capacity to assess mangrove vulnerability to climate change and to institute adaptation measures. Regional adaptation priorities include coastal planning that facilitates mangrove migration with sea-level rise, better management of non-climate stressors, and identification of climate change impacts on mangroves through regional standardized monitoring.

碩士
國立中興大學
生命科學系所
102
Mangrove and marsh plants absorb atmospheric CO2 via photosynthesis, which was then transferred to organic carbon and stored as biomass. Quantifying plant net primary production and carbon export can be used to estimate the carbon budget. This study was conducted from August 2011 to October 2012 every two months. In total, there were 5 study sites ( HJ, WG, GD, ZW and WZ ) along the Danshuei River from upstream to the estuary. The primary production of the mangrove plant Kandelia obovata was calculated using an allometric equation with estimated biomass and collected litter fall. Primary production of the dominant marsh plant Phragmites australis was calculated using the harvest method. The carbon export out of plant was also estimated from river. The net primary production of mangroves was estimated to be 7.09, 4.46 and 6.71 g DW m-2 d-1 at the three sites (WZ, ZW and GD), indicating an uptake of 546 ton C within a year. The net primary production of marshes was 20.32 and 25.73 g DW m-2 d-1 at the two sites (WG and HJ), indicating an uptake of 971 ton C within a year. In total, vascular plants along the Danshuei River uptook 1,517 ton C. The carbon stock of the mangroves and marshes were 944 and 663 Mg C ha-1. There was about 93 to 97 % carbon stored in the soil. These mangroves and marshes export 3.91 or 3.20 ton C to the river water every year. The net ecosystem production of mangroves and marshes were estimated to be 4.61 and 27.20 Mg C ha-1 yr-1, indicating they were important carbon sinks along the Danshui River.