Thèse (M.A.) -- Université Laval, 1997. / Bibliogr.: f. 108-121. Publié aussi en version électronique.

Twin Cays, Belize, is dominated by Rhizophora mangle L. (red mangrove). Tall (>5m in height) R. mangle are located along the fringe of the island and dwarf R. mangle grow in the interior of the island. These stand structures can be differentiated using δ13C and δ15N analysis (mean tall δ13C = -28 ‰, mean tall δ15N = 0‰; mean dwarf δ13C = -25‰, mean dwarf δ15N = -10‰), which may also prove useful in examining past mangrove stand structures from sediment cores. 15N label was traced in R. mangle leaves in a laboratory and field experiment over three months. The 15N label was examined to determine distribution of nitrogen in various biochemical fractions of the leaf and to verify if nitrogen is fractionated in a predictable manner over time. This information could be beneficial in examining past mangrove stand structures. Experimental data indicate that nitrogen is mobile within each biochemical fraction of the R. mangle leaf over time and a measurable amount of nitrogen exists in each fraction after 3 months of incubation. Nitrogen immobilization was evident in each experiment, as the δ15N values decreased ~200‰ in each of the labeled fractions of the laboratory experiment, which was mirrored by an increase in δ15N in the control samples. The amount of nitrogen in the biochemical fractions of the field experiment varied over time either increasing or decreasing, which may be due to the various environmental conditions such as tidal fluctuation, temperature, oxygen concentrations and microbial activity. The δ15N signature of the residual nitrogen fraction (δ15N = 87‰) reflected that of the bulk fraction (δ15N = 133‰) in the laboratory experiment as well as in the field experiment (residual nitrogen δ15N = 759‰, bulk δ15N = 770‰). To use isotope analysis to examine past mangrove stand structures it is essential that the original signature be maintained over time. The results of this study indicated that the simple interpretation of nitrogen isotopes may not be useful in examining past mangrove stand structures due to the variation over time, although this type of analysis may be considered if coupled with additional proxies and diagenetic factors are taken into account.

Twin Cays, Belize, is dominated by Rhizophora mangle L. (red mangrove). Tall (>5m in height) R. mangle are located along the fringe of the island and dwarf R. mangle grow in the interior of the island. These stand structures can be differentiated using δ13C and δ15N analysis (mean tall δ13C = -28 ‰, mean tall δ15N = 0‰; mean dwarf δ13C = -25‰, mean dwarf δ15N = -10‰), which may also prove useful in examining past mangrove stand structures from sediment cores. 15N label was traced in R. mangle leaves in a laboratory and field experiment over three months. The 15N label was examined to determine distribution of nitrogen in various biochemical fractions of the leaf and to verify if nitrogen is fractionated in a predictable manner over time. This information could be beneficial in examining past mangrove stand structures. Experimental data indicate that nitrogen is mobile within each biochemical fraction of the R. mangle leaf over time and a measurable amount of nitrogen exists in each fraction after 3 months of incubation. Nitrogen immobilization was evident in each experiment, as the δ15N values decreased ~200‰ in each of the labeled fractions of the laboratory experiment, which was mirrored by an increase in δ15N in the control samples. The amount of nitrogen in the biochemical fractions of the field experiment varied over time either increasing or decreasing, which may be due to the various environmental conditions such as tidal fluctuation, temperature, oxygen concentrations and microbial activity. The δ15N signature of the residual nitrogen fraction (δ15N = 87‰) reflected that of the bulk fraction (δ15N = 133‰) in the laboratory experiment as well as in the field experiment (residual nitrogen δ15N = 759‰, bulk δ15N = 770‰). To use isotope analysis to examine past mangrove stand structures it is essential that the original signature be maintained over time. The results of this study indicated that the simple interpretation of nitrogen isotopes may not be useful in examining past mangrove stand structures due to the variation over time, although this type of analysis may be considered if coupled with additional proxies and diagenetic factors are taken into account.

Th. doct.--Sciences de la terre--Nancy 1, 1994. / Bibliogr. p. 213-227.

Mangroves are a group of the intertidal plants with unrelated phylogenetic affinity distributed in regions of estuaries, riverbanks or along the coastlines of tropical and subtropical areas. The four genera of tribe Rhizophoreae of Rhizophoraceae are important members of mangroves, namely Bruguiera, Ceriops, Kandelia and Rhizophora and also known as mangrove Rhizophoraceae, with a wide distribution range. Fourteen of 17 species of mangrove Rhizophoraceae distributed in the areas between the Eastern Africa to the Pacific West Coast, belong to the eastern mangrove Rhizophoraceae. Thirteen species of the eastern mangrove Rhizophoraceae from different populations were sampled for the studies in comparative morphology and anatomy on stipules, leaves, flowers, fruits and viviparous seedlings. In contrast, four species of three genera belong to the inland Rhizophoraceae were also sampled. Such works were emphasized on stipules and leaves. Three kinds of sclereids were found in the stipules of Ceriops and Rhizophora, but none in Kandelia and Bruguiera. Several to hundreds colleters arranging in several series occur at the adaxial base of a stipule in Rhizophoraceae. The aggregated forms, series number, number and individual morphology of colleters are generic or specific, and could be an aid for taxonomic identification. The number and size of colleters found in the mangrove Rhizophoraceae are more and larger than those of the inland species. Additionally, the size of stipule in mangrove Rhizophoraceae is larger than those of the inland Rhizophoraceae. These characters might imply an adaptive selection of stipule and colleters in Rhizophoreae. In this study, many of the previous discrepancies of leaf anatomical features were clarified. Meanwhile, the plasticity of leaf structure, features of sclereid ideoblasts and crystals were not previously reported. The leaves of mangrove Rhizophoraceae present thick leaves and cuticular wax, sunken and cyclocytic stomata with distinct inner and outer ridges, 2 to 8 cell-layered hypodermis, enlarged terminal tracheids, four types of sclereid ideoblasts and abundant tanniferous cells and drused crystals. All species of the mangrove Rhizophoraceae has potential to produce cork warts on both sides, but only Rhizophora has the warts mainly on abaxial side regularly. Detailed stomatal features could serve as diagnostic character in species level. On the contrary, the inland species has thin leaves with less cuticular wax, superficial anomocytic stomata, no hypodermis and enlarged terminal tracheids, drused and raphid crystals. The diverse morphological features in flowers and fruits, especially in inflorescences, petals and stamens, provided valuable and reliable taxonomic characteristics. A detailed survey for flower and fruit parts (including the viviparous seedlings) were provided in this study. Some unique and curious phenomenon, including multi-cotyledons to united cotyledon and cotyledon collar, endosperm overflow, the present of coleorhiza in the hypocotyl of Bruguiera, provided interesting and valuable embryological information for the mangrove Rhizophoraceae. Downward and upward orientation seedlings on the mother trees were observed, however the latter were not noticed previously. Two new taxa were recognized based on many lines of evidences in this study. A new species, Kandelia obovata C. R. Sheue, H. Y. Liu and J. W. H. Yong, which distributed northern from the South China Sea, was named and described. The detailed morphological and anatomical features of Ceriops australis (C. T. White) E. R. Ballment, T. J. Smith III & J. A. Stoddart were firstly described, which confirmed its taxonomic status. A systematic approach with a global view on the mangrove Rhizophoraceae is still needed, especially for Ceriops and Rhizophora.

Thèses (M.Env.)--Université de Sherbrooke (Canada), 2005. / Titre de l'écran-titre (visionné le 20 juin 2006). Publié aussi en version papier.

Thèses (M.Sc.)--Université de Sherbrooke (Canada), 2005. / Titre de l'écran-titre (visionné le 20 juin 2006). Publié aussi en version papier.

L’augmentation des concentrations atmosphériques en CO2, et le forçage radiatif induit, mobilise la communauté scientifique à étudier les potentialités des écosystèmes à fixer puis stocker le carbone. Les mangroves représentent un des écosystèmes les plus productifs au monde. Cependant, 50% de sa productivité primaire nette n’est pas identifiée dans le devenir du carbone organique produit. Ainsi les flux de CO2, proxy de la minéralisation de la matière organique, issus des sols de mangrove ainsi que de leurs chenaux, sont considérée comme sous-estimés. Cette thèse a eu pour objectifs de comprendre la variabilité spatio-temporelle des flux de CO2 issus de ces deux compartiments. Une mangrove de la côte ouest de la Nouvelle Calédonie, présentant une zonation de type tanne nu, Avicennia sp. et Rhizophora spp., a été étudiée. La position dans la zone intertidale semble être un paramètre déterminant dans la variabilité des flux. D’une part, elle détermine des paramètres abiotiques susceptibles d’affecter la dégradation de la matière organique, et d’autre part, définit partiellement la végétation colonisant le milieu, qui en retour pourra affecter les flux. La variabilité saisonnière est, quant à elle, fortement liée à l’évolution de la température et de l’humidité du sol. Les chenaux de mangrove sont riches en éléments organiques et inorganique dissous, vraisemblablement du fait d’apports advectifs des eaux interstitielles, et présentent une sursaturation marquée en CO2. Les chenaux ainsi que la rivière traversant la mangrove fonctionnent, comme sont une source nette de CO2 pour l’atmosphère. Cependant, les apports de carbone de la mangrove vers l’estuaire semblent être rapidement dilués par les masses d’eau lagonnaires. Finalement, la variabilité saisonnière des flux de CO2 issus de la colonne d’eau semble être liée principalement à l’évolution des apports de carbone organique provenant des bassins versants notamment lors de dépressions tropicales, et donc le rôle de la mangrove dans la productivité du lagon reste flou, et devra être démontré à l’aide d’outils moléculaires. / The increase of atmospheric CO2 concentrations, and its radiative effect, mobilizes the scientific community to explore the potential of ecosystems to fix and store carbon. Mangroves are one of the most productive ecosystems in the world. However, 50% of its net primary productivity is not identified in the fate of the organic carbon produced. CO2 fluxes, which are a proxy of organic matter mineralization, from mangrove soils and their channels are considered underestimated. The purpose of this thesis was to understand the spatio-temporal variability of CO2 fluxes from these two compartments. A mangrove forest on the west coast of New Caledonia, composed of a saltflat, Avicennia sp. and Rhizophora spp. was studied. Elevation in the intertidal zone seems to be a determining factor in fluxes variability. On the one hand, it determines the abiotic parameters that affect the degradation of organic matter, and on the other hand, elevation partially defines the vegetation colonizing the environment, which in turn may affect the fluxes. Fluxes seasonal variability is closely linked to the evolution of temperature and soil moisture. Mangrove creeks are rich in dissolved organic and inorganic compounds, presumably due to the advection of porewaters, and are thus characterized by CO2 oversaturation. Creeks and the river crossing the mangrove are a net source of CO2 to the atmosphere. However, the contribution of mangrove-derived carbon to the estuary seems to be rapidly diluted by lagoon waters. Finally, the seasonal variability of CO2 fluxes from the water column appears to be related primarily to the evolution of organic carbon inputs from watersheds notably during tropical depressions, and thus the role of mangroves in the lagoon productivity remains unclear, and should be studied using molecular tools.

Mumbai is the economic capital and the most densely urbanized coastal city of India. Environmental strain caused by rapid development of the city is studied with focus on one aspect of Mumbai's environment, the mangrove ecology, which has been threatened by urbanization ever since the city began to evolve. The development authority of the city proposes a regional plan to guide future growth. An addendum to this regional plan is part of this thesis. The process of developing a mangrove mitigation plan is discussed in this paper. The paper analyzes the potential mangrove stand, which can be restored, and why they need to be restored. This thesis recommends mangrove conservation and restoration policies for Mumbai, based on the process of data collection, data structuring, comparative analysis and development of implementation strategies. A study of Mangrove management policies implemented in other countries and coastal cities supports the mangrove management strategies suggested for the city of Mumbai. Future land development proposed by the development authority of Mumbai has been analyzed to identify probable impacts on mangrove ecology and to highlight mangrove mitigation sites. These sites offer a platform for active mangrove management that will provide important environmental services to Mumbai in the future. / Master of Landscape Architecture

The mangrove swamp, a woody plant community, grows in the coastal marsh and tidal zone in the tropical and subtropical zones. The general definition of the community means that mangrove swamps are composed of the landholding things which grow in the tropical and subtropical tidal zones. The strict definition refers that mangrove swamps are composed of arbors or shrubs which grow between the flood mark and average flood mark in the tropical coast. This research aims at studying the composition and distribution of mangroves in Kaohsiung and Pingdong County. The multiple-plot method was used in the study. There are 28 plots sampled. Based on the environmental situation, the samples consisted 10 to 177 small plots which are 1x1 square meter in size. In each plot, the trees which have DBH over 1 centimeter are all measured. Their heights are estimated and recorded. Estimation of tree number in each area, density, and average DBH was made. Five species of mangrove trees are found. They are¡G Kandelia obovata Sheue, Liu¡®Yong, Rhizophora stylosa Griff ( Rhizophoraceae ), Avicennia marina (Forsk .) Vierh ( Verbenaceae ), Lumnitzera racemosa Willd ( Combretaceae ) and Excoecaria agallocha L ( Euphorbiaceae). Bruguiera gymnorhiza and Ceriops tagal in the early research have been disappeared. There are 125 woody and herbaceous species in the mangroves which belong to 36 families and 100 genera. The mangroves mainly grow in the conservation area in the river mouths of Kaohsiung and Pingdong Country. The remaining mangroves are scattered in the areas. The mangroves were previously flourished in Kaohsiung Harbor in the south of Taiwan, but, now,there are only 12 individuals of Avicennia marina and a single tree of Lumnitzera racemosa growing in the east of Qijin. The mangroves comprise mainly Avicennia marina. The southernmost distributional area of the species is Xinlong Village in Fanglian. A few individuals of Rhizophora stylosa grow near the mouth of the Houchin stream . Many individuals of Excoecaria agallocha are found near Dapengwan of Pingdong and some of them form pure stands along streams near coastal area. The curve of diameter and structural analyses of Avicennia stands is bell shape, which is possibly the results of human affection. Because of the development in the coast in past decades, mangroves have become decreased, and will be probably disappeared in the future, if they are not protected intensively.