Lepidoptera (butterflies and moths) comprises a fairly well-studied invertebrate taxon. The body of knowledge that has been acquired, especially on butterflies, allows for more convincing assessments of the significance of species distributions, for example assessments of rarity and endemism. In spite of their taxonomically well-known status, little is known about the different ranges and limiting factors controlling habitat specificity amongst species at a local scale. Aiming at ensuring more efficient and inclusive conservation planning for new developments and for rehabilitation of disturbed areas this study focused on the identification of species specific and local scale (biotopic) microhabitat attractants. This was done by identifying and classifying locally occurring butterflies in the context of small scale habitat preferences on a spatial and temporal scale taking into account correlations in distributions of butterflies, plants and bio-physical gradients. Results were compared to previous studies to evaluate the use of recorded species as bio-indicators. The methodology entailed the use of twelve 250m fixed belt transects that were sampled in alternating directions across four sites within the West Coast National Park. Seven sampling sessions were set out during four sampling months mainly during the summer of the 2006/07 season. Sampling was conducted through visual observations while walking transects at a constant pace. Distributional variation between species was observed within a relatively small area with limited apparent variation in vegetation, topography and altitude. Pronounced temporal variation and correlation between butterfly species distribution and microhabitats were observed although this is strongly linked to the scale of the study in relation to the species studied. Factors that will affect the choice of microhabitat across time include amongst others: the prevailing sex ratio, temperature and the presence of invasive ants. The influence of plant distribution in predicting butterfly species distribution seemed to be less important. Myrmecophilous butterflies could probably play some role in bio-indication although much more work needs to be done to confirm this. The identification of stepping stone sites with optimum microhabitats during the environmental assessment phase in areas with endangered butterfly species should determine the face of the development and not the other way around. / Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2010.

Lepidoptera (butterflies and moths) comprises a fairly well-studied invertebrate taxon. The body of knowledge that has been acquired, especially on butterflies, allows for more convincing assessments of the significance of species distributions, for example assessments of rarity and endemism. In spite of their taxonomically well-known status, little is known about the different ranges and limiting factors controlling habitat specificity amongst species at a local scale. Aiming at ensuring more efficient and inclusive conservation planning for new developments and for rehabilitation of disturbed areas this study focused on the identification of species specific and local scale (biotopic) microhabitat attractants. This was done by identifying and classifying locally occurring butterflies in the context of small scale habitat preferences on a spatial and temporal scale taking into account correlations in distributions of butterflies, plants and bio-physical gradients. Results were compared to previous studies to evaluate the use of recorded species as bio-indicators. The methodology entailed the use of twelve 250m fixed belt transects that were sampled in alternating directions across four sites within the West Coast National Park. Seven sampling sessions were set out during four sampling months mainly during the summer of the 2006/07 season. Sampling was conducted through visual observations while walking transects at a constant pace. Distributional variation between species was observed within a relatively small area with limited apparent variation in vegetation, topography and altitude. Pronounced temporal variation and correlation between butterfly species distribution and microhabitats were observed although this is strongly linked to the scale of the study in relation to the species studied. Factors that will affect the choice of microhabitat across time include amongst others: the prevailing sex ratio, temperature and the presence of invasive ants. The influence of plant distribution in predicting butterfly species distribution seemed to be less important. Myrmecophilous butterflies could probably play some role in bio-indication although much more work needs to be done to confirm this. The identification of stepping stone sites with optimum microhabitats during the environmental assessment phase in areas with endangered butterfly species should determine the face of the development and not the other way around. / Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2010.

Submitted by Milena Rubi (milenarubi@ufscar.br) on 2017-02-24T15:58:06Z No. of bitstreams: 1 FERNANDES_Gerson_2016.pdf: 13725241 bytes, checksum: 4bf54868355621d2ad09ae85d6c244f4 (MD5) / Approved for entry into archive by Milena Rubi (milenarubi@ufscar.br) on 2017-02-24T15:58:17Z (GMT) No. of bitstreams: 1 FERNANDES_Gerson_2016.pdf: 13725241 bytes, checksum: 4bf54868355621d2ad09ae85d6c244f4 (MD5) / Approved for entry into archive by Milena Rubi (milenarubi@ufscar.br) on 2017-02-24T15:58:24Z (GMT) No. of bitstreams: 1 FERNANDES_Gerson_2016.pdf: 13725241 bytes, checksum: 4bf54868355621d2ad09ae85d6c244f4 (MD5) / Made available in DSpace on 2017-02-24T15:58:30Z (GMT). No. of bitstreams: 1 FERNANDES_Gerson_2016.pdf: 13725241 bytes, checksum: 4bf54868355621d2ad09ae85d6c244f4 (MD5) Previous issue date: 2016-09-21 / Não recebi financiamento / The study aimed to evaluate restored areas implemented in the basin of the Sorocaba River and Middle Tiete based on terms of commitments to environmental restoration and conduct adjustment terms. We selected two to three projects in each sub-basin to those with the presence of restoration, certified by the consent of the owner. In each restoration, we evaluated attributes of species diversity and functions, control and management, soil protection and nutrient cycling. The restored areas restoration presented 17 ± 10 species, under the condition established by law, mortality was high, around 40% with an average of 1090 individuals/ha. Croton floribundus, Schinus terebinthifolius, Guazuma ulmifolia, Inga vera, Citharexylum myrianthum, Cordia sellowiana represented 31.7% of species planted and together with Enterolobium contortisiliquum, colubrina Anadenanthera, C. urucurana, Ceiba speciosa, Eugenia uniflora, Lithraea molleoides, Psidium guajava, Triplaris americana, Erythrina speciosa represented 52.8% of the planted individuals. The restoration were in critical situation and, although species richness is according to legal requirements, we observed the concentration on few common and frequent species in general pioneers. Regardless of age, the studied areas did not restore the structural and physical aspects of the forest, and were not efficient in the establishment of ecological processes, highlighting the need to review the procedures adopted in the legal and technical mechanisms of restoration in the region. / O estudo teve por objetivo avaliar projetos de restauração de áreas degradadas implantados na bacia dos Rios Sorocaba e Médio Tietê realizados a partir de termos de compromissos de restauração ambiental e termo de ajustamento de conduta. Foram selecionados dois a três projetos em cada sub-bacia entre os que apresentavam presença da restauração, atestada pela anuência do proprietário. Em cada restauração foram avaliados os atributos da diversidade de espécies e de funções, controle e manejo, proteção do solo e ciclagem de nutrientes. As áreas em restauração apresentaram 17±10 espécies, abaixo da condição estabelecida pela legislação, com alta mortalidade, em torno de 40% e média de 1090 indivíduos/ha. Das espécies, Croton floribundus, Schinus terebinthifolius, Guazuma ulmifolia, Inga vera, Citharexylum myrianthum, Cordia sellowiana, representaram 31,7% dos indivíduos e, juntamente com Enterolobium contortisiliquum, Anadenanthera colubrina, Croton urucurana, Ceiba speciosa, Eugenia uniflora, Lithraea molleoides, Psidium guajava, Triplaris americana, Erythrina speciosa somaram 52,8% dos indivíduos plantados. Os projetos de restauração foram considerados em situação crítica e, embora apresentem riqueza dentro do recomendado, concentraram-se em poucas de espécies mais comuns e frequentes, em geral pioneiras. Independentemente da idade, as áreas estudadas não restauraram os aspectos estruturais e físicos da floresta, e não foram eficientes no estabelecimento dos processos ecológicos, evidenciando a necessidade de se rever os procedimentos adotados nos mecanismos legais e técnicos da restauração na região.

Concentrations of herbicides in our aquatic ecosystems increase more and more. Among these, the herbicide glyphosate is the most common one. This ecotoxicological study was performed in order to examine the toxic effect of the herbicide glyphosate on aquatic invertebrates. Odonata were selected as study organisms in order to serve as bio-indicators of environmental contamination. Two populations, each of two species (Erythromma najas and Libellula quadrimaculata) were collected from four different locations, to study inter-specific differences, as well as, differences among populations within a species, in response to herbicide exposure. The experiment was conducted for 15 days in a 2 x 4 factorial design with 4 replicates (n = 32). The most common brand of weed-killer ‘Roundup’ containing 7.2 gL-1 of glyphosate) was used as source of glyphosate. Glyphosate was applied at a concentration of 7.6 mgL-1 in the experiment equalling the high end of environmentally relevant concentrations of glyphosate present in contaminated shallow waters. Response variables measured were larval survival, growth and activity. The results showed that glyphosate exposure reduced the survival of the larvae, but the magnitude of the glyphosate effects depended on species identity of the larvae and varied also with population within species. This study clearly shows that herbicide effects on invertebrate fitness depends on species identity and may even vary within species from different populations, possibly due to evolved resistance of random genetic variations between populations or due to random genetic variation between populations.

Spongiaires Irciniidae de Méditerranée : Chimiotaxonomie, métabolites volatils et bio-indicateurs de pollution par les éléments traces métalliquesLe projet de recherche qui m’a été confié concerne l’étude des éponges Irciniidae de Méditerranée : Ircinia oros, I. variabilis, I. dendroides, Sarcotragus spinosulus et S. foetidus ; collectées, dans le cadre du programme ECIMAR (ANR Biodiversité 2006), dans huit différents sites : détroit de Gibraltar (Ceuta - Espagne), bassin nord occidental (Costa Blanca et l’Estartit – Espagne et Banyuls, Marseille et l’île de Corse - France) et le bassin oriental (Crète - Grèce et Liban).La famille Irciniidae est actuellement constituée de trois genres : Ircinia, Sarcotragus et Psammocinia. La systématique de ces éponges est relativement complexe. Ainsi, le statut de Sarcotragus est considéré comme incertain et la distinction entre certaines espèces d’Ircinia fait encore l’objet de nombreuses discussions. Pour tenter de clarifier ce désordre de la classification biologique, nous avons choisi, dans un premier temps, une étude chimiotaxonomique basée sur la RMN 1H et les analyses multivariées. Par cette approche de métabolomique des différentes espèces, nous avons pu démontrer que les genres Ircinia et Sarcotragus sont caractérisés, d’un point de vue chimique, par des marqueurs chimiotaxonomiques appartenant respectivement à la famille des furanoterpènes et des hydroquinones prénylées.Dans un second temps, nous avons mené une étude comparative des composés volatils présents dans les espèces I. oros, I. variabilis, I. dendroides et S. spinosulus, provenant de trois sites : Marseille, Ceuta et Costa blanca. En effet, des composés volatils comme le diméthylsulfure, le méthylisocyanate et le méthylisothiocyanate, sont présents dans Ircinia felix et ils sont responsables de la forte odeur caractéristique et nauséabonde de cette espèce. L’identité et le rôle écologique potentiel de l’ensemble des volatils sont encore peu étudiés. Plusieurs hypothèses concernant leurs origines ont été proposées (éponge et/ou symbiote) sans toutefois parvenir à une conclusion certaine. De plus, les composés volatils présents dans les éponges Sarcotragus n’ont pas été étudiés, bien qu’elles se distinguent également par une forte odeur. Dans ce cadre, nous avons mis au point un protocole d’étude des composés volatils des spongiaires en utilisant la microextraction SPME de l’espace de tête et l’analyse par CG-SM et/ou CG*CG-MS. Les composés identifiés sont des alcanes, des alcènes, des aldéhydes, des dérivés furaniques et soufrés, issus fort probablement de la dégradation de terpénoïdes par les bactéries associées aux éponges.Enfin, nous avons réalisé une étude comparative de la bioaccumulation d’éléments trace métalliques (ETM) par I. oros, I. variabilis et S. spinosulus, afin d’identifier de potentiels bioindicateurs de pollution par les ETM dont la contamination a considérablement augmenté en Méditerranée pendant ces 20 dernières années. Notre étude a révélé que les différentes espèces semblent bioaccumuler l’arsenic, le chrome, le cuivre, le fer et le plomb, alors qu’elles régulent le cadmium. / The Irciniidae marine sponges from the Mediterranean Sea: secondary metabolism, volatile compounds and potential bio-indicators of a heavy metal pollutionMarine sponges of the Irciniidae family (I. oros, I. variabilis, I. dendroides, S. spinosulus and S. foetidus) collected during the french ANR program ECIMAR from eight different areas over the Mediterranean Sea: Gibraltar Straits (Ceuta - Spain), North Western basin (Costa Blanca and Estartit – Spain and Banyuls, Marseille and Corsica Island - France, and Monaco) and Eastern basin (Crete - Greece and Lebanon) were studied.We used first a chemotaxonomical approach based on 1H NMR chemical fingerprints and multivariate analysis to better characterize the species. Systematic of the Irciniidae family is still unclear, notably the status of Sarcotragus is viewed as uncertain and the distinction of some Ircinia species remains difficult. To clarify this biological classification disorder, we used a chemosystematics strategy. In the present study, we showed that Ircinia and Sarcotragus genera are chemically characterized by chemotaxonomic markers belonging to furanoterpenes and prenylated hydroquinones families respectively. We report also a comparative GC-MS analysis of the volatile components of S. spinolusus, I. oros, I. variabilis and I. dendroides using static headspace solid phase microextraction (HS-SPME). Sponges of the genus Ircinia were described to exude low-molecular-weight volatile compounds (e.g., dimethyl sulfide, methyl isocyanide, methyl isothiocyanate) that give these sponges a characteristic strong and unpleasant odor. To date, the volatile constituents of sponges of the genus Sarcotragus have not been studied, though their odor is no lighter than the associated genus Ircinia from the same family. The impact of different parameters (e.g., sample weight, fiber coating, extraction time and temperature) was evaluated to determine the best conditions of analysis. The types of compounds identified include alkanes, alkenes, aldehydes, ketones, furans, and sulfides probably produced from bacterial degradation of naturally occurring terpenoids. Finally, we performed a comparative study on metal bioaccumulation by I. oros, I. variabilis, and S. spinosulus to select the most suitable species for metal monitoring. Contamination by heavy metals has increased drastically in the coastal Mediterranean during the last 20 years. Arsenic, chromium, copper, iron and lead bioaccumulation were shown to fit an accumulation strategy, while cadmium seemed to be bio-regulated.

Le sol, composante du Terroir doit être considéré comme une ressource non renouvelable essentielle au fonctionnement des agroécosystèmes. Or, les sols viticoles sont particulièrement vulnérables aux dégradations. L’objectif central de ma thèse est donc d’évaluer comment les pratiques viticoles affectent la qualité des sols dans le Languedoc-Roussillon. Pour ce faire, j’ai d’abord évalué la qualité des sols sur 164 parcelles présentant une grande variabilité de pratiques culturales et réparties sur 9 zones pédologiques très diversifiées. Puis, j’ai évalué la vitesse de changement de la qualité des sols par l’analyse de 24 parcelles d’une zone homogène converties progressivement en viticulture biologique depuis un maximum de 17 ans. Plusieurs indicateurs physiques (densité apparente, porosité totale, stabilité structurale et humidité à la capacité au champ), chimiques (teneur en carbone et azote, C/N, disponibilité des éléments P, K, et Cu, capacité d’échange cationique) et biologiques (biomasse microbienne, respirométrie, nématodes, vers de terre) ont été mesurés afin de fournir une vision holistique de la qualité des sols. Mes résultats montrent une diversité de qualité des sols viticoles au regard des perturbations subies par les différentes pratiques. J’ai également démontré que la majorité des indicateurs étudiés sont sensibles aux pratiques viticoles indépendamment des types de sol étudiés. Concernant la dynamique de changement, la qualité des sols viticoles se stabilise après 7-11 de pratiques biologiques. Toutefois, malgré une augmentation significative des activités biologiques du sol (micro-organismes et nématodes libres), la conversion depuis 17 ans n’a pas mis en évidence une amélioration nette de la qualité du sol. En conclusion, nous avons confirmé la vulnérabilité des sols viticoles languedociens aux pratiques en cours. Mes travaux mettent en lumière l’importance du transfert des connaissances acquises lors de ce travail pour améliorer la perception de la qualité des sols par les viticulteurs et les professionnels de la filière viticole. / Soils should be considered as a non-enewable yet essential resource for agroecosystem functioning. Animportant component of the Terroir, vineyard soils are nevertheless particularly vulnerable to degradation.The main objective of my PhD was to assess the effect of viticultural practices on soil quality in theLanguedoc©Roussillon region. In this aim, I first assessed soil quality on 164 vineyard plots representing awide range of viticultural practices and located in 9 contrasted soil type zones. I then estimated the speed of change in soil quality, by analyzing 24 plots from one homogeneous zone after their conversion toorganic viticulture, undertaken 1 to 17 years ago. Several physical (bulk density, total porosity, structuralstability and soil moisture at field capacity) as well as chemical (carbon and nitrogen content, C/N, P, K and Cu availability, cation exchange capacity) and biological (microbial biomass, respiration, nematode andearthworm abundance) indicators were measured in order to provide a holistic appraisal of soil quality. Myresults show that the variability of vineyard soil quality reflects the perturbations inflicted by differentmanagement practices. I have also established that the majority of the studied indicators are sensitive toviticultural practices, independently of soil type. The study of the dynamics of the change in vineyard soilquality revealed stabilization after 7 to 11 years of organic management practices. However, despite asignificant increase in biological activity (microbial biomass and free©living nematode abundance), no clearimprovement in soil quality was apparent 17 years after conversion to organic viticulture. In conclusion, we have confirmed the vulnerability of Languedoc©Roussillon vineyard soils to current management practices. My work highlights the importance of transferring the acquired knowledge to winegrowers and wine sector professionals in order to improve their perception of soil quality.

Submitted by Daniele Amaral (daniee_ni@hotmail.com) on 2016-09-20T20:25:38Z No. of bitstreams: 1 DissBLG.pdf: 2379490 bytes, checksum: 67fda0f4c79652eac1e6aeb1d1cc9785 (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2016-09-20T20:33:16Z (GMT) No. of bitstreams: 1 DissBLG.pdf: 2379490 bytes, checksum: 67fda0f4c79652eac1e6aeb1d1cc9785 (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2016-09-20T20:40:19Z (GMT) No. of bitstreams: 1 DissBLG.pdf: 2379490 bytes, checksum: 67fda0f4c79652eac1e6aeb1d1cc9785 (MD5) / Made available in DSpace on 2016-09-20T20:40:32Z (GMT). No. of bitstreams: 1 DissBLG.pdf: 2379490 bytes, checksum: 67fda0f4c79652eac1e6aeb1d1cc9785 (MD5) Previous issue date: 2015-06-02 / Não recebi financiamento / Birds contribute to many kinds of environmental services, such as predation on arthropods, which results in their population control, and reduced folivory and higher growth rates of plants. In addition, insectivorous birds are sensitive to environmental disturbances, requiring protected areas for conservation and being indicators of environmental quality. In this research, we sampled the insectivorous birds and tested whether they affect the abundance of arthropods and folivory rates. We compared three areas of different successional stages and management, and seasonality in a protected area of Atlantic Forest in southeastern Brazil. The areas selected were anthropic area (“sede”), early and advanced stages of succession. We carried out samplings of birds through 12 fixed points for 13 months and classified species in guilds, grouping the consumers of arthropods between strict and facultative insectivorous. We also proceed a twice bird exclusion experiment (rainy and dry season), comparing arthropod abundance and foliar damage in covered vs. non-covered branches. A total of 186 species of birds have been recorded, with 142 consumers of arthropods. The composition of birds was affected by spatial variation, as the temporal variation presented a diffuse influence. The advanced stage area hosts a higher species richness of specialists, threatened, endemic and with a high degree of environmental sensitivity. The “sede” adds generalist and low degree of sensitivity species. The exclusion of birds resulted in a significant increase in abundance (z=24,682, p = 0) and diversity (z=12,825, p = 0) of arthropods, but this was not reflected in differences in folivory; thus which may be driven by other factors such as the bottom-up effect. The abundance of arthropods showed an inverse relationship with the abundance of strict and facultative insectivorous birds and this control through predation occurred in all areas, suggesting the importance of omnivorous species. The spatial variation of insectivorous birds highlights the potential of each sampled area for maintenance of the functional role of these birds, and this might be considered for management practices. / As aves contribuem para diversos tipos de serviços ambientais, como a predação de artrópodes, que resulta em seu controle populacional, redução na folivoria e maiores taxas de crescimento das plantas. Além disso, aves insetívoras são sensíveis às perturbações ambientais, necessitando de áreas protegidas para sua conservação e sendo indicadores de qualidade ambiental. Neste trabalho nós caracterizamos a avifauna insetívora e testamos o efeito desta sobre a abundância de artrópodes e taxas de folivoria, comparando três áreas de estágios sucessionais, usos e zoneamento distintos e períodos do ano em uma área protegida de Mata Atlântica no sudeste do Brasil. As áreas selecionadas foram: área antropizada (sede), estágio inicial e estágio avançado de sucessão. Para isso, realizamos a amostragem da avifauna por meio de 12 pontos fixos durante 13 meses, classificamos as aves em guildas e agrupamos os consumidores de artrópodes entre insetívoras estritas e facultativas. Também fizemos um experimento de exclusão de aves aplicado duas vezes (estação chuvosa e seca). Analisamos a abundância de artrópodes coletados e o dano foliar ocorrido durante o experimento em ramos com rede de exclusão e controle. 186 espécies de aves foram registradas, sendo 142 consumidoras de artrópodes. A composição de aves foi afetada pela variação espacial, já a variação temporal apresentou uma influência difusa. A área de estágio avançado abriga maior riqueza de espécies especialistas, ameaçadas, endêmicas e com alto grau de sensibilidade ambiental, mas estas também estão presentes nas outras áreas. A sede adiciona espécies generalista e de baixo grau de sensibilidade à área estudada. A remoção das aves resultou em um aumento significativo da abundância (z=24,682, p=0) e diversidade (z=12,825, p=0) de artrópodes, porém isso não refletiu em diferenças na folivoria e esta pode estar sendo controlada por outros fatores como o efeito bottom-up. A abundância de artrópodes apresentou relação inversa com a abundância de aves insetívoras estritas e facultativas e este controle por meio da predação ocorreu em todas as áreas, indicando a importância de espécies onívoras. Nossos resultados mostram que a variação espacial da avifauna insetívora evidencia as potencialidades de cada área, sendo que todas apresentam a manutenção do papel funcional destas aves. É importante que estes pontos sejam considerados no manejo de cada zona para ações efetivas na conservação.

Les amibes à thèque, également appelés thécamoebiens, sont des micro-organismes unicellulaires, qui construisent une enveloppe rigide, appelée thèque (Adl et al., 2012). Ces thèques ont des tailles, formes et natures très variées (Ogden & Hedley, 1980). Les récentes études sur la composition des thèques ont conduit à émettre l’hypothèse que les amibes xénosomiques (constituées de particules exogènes), peuvent constituer des bio-indicateurs pertinents de la diversité particulaire de l’environnement minéral, organique et biologique dans lequel elles évoluent.L’objectif principal des recherches menées au cours de cette thèse vise donc à caractériser la composition des thèques d’amibes xénosomiques et à en évaluer leur utilisation potentielle en tant que bio-indicateurs des dépôts de particules d'origine atmosphérique. Pour cela, des thèques d’amibes ont été analysées in situ en conditions naturelles et après dépôts artificiels de particules minérales allochtones.Ces travaux permettent de dégager plusieurs conclusions majeures :(1) La taille des particules minérales intégrées dans la thèque xénosomique de Bullinularia indica est similaire à celle des particules minérales transportées dans l'atmosphère; (2) les particules minérales intégrées dans les thèques sont des silicates stables dans les conditions physico-chimiques régnant dans les tourbières, les bryophytes et les sols étudiés; (3) certains minéraux comme la phlogopite, même lorsqu’ils sont présents en de fortes concentrations, ne sont jamais intégrés par les amibes; (4) la combinaison des observations portant sur la taille, la forme et la nature des particules utilisées par des amibes xénosomiques permet de poser les bases de l'utilisation des amibes à thèques pour la bio-indication de la diversité particulaire atmosphérique récente ou ancienne. / Theca-like amoebae, also called thecaamoebius, are unicellular microorganisms, which construct a rigid envelope called theca (Adl et al., 2012). These themes have very varied sizes, shapes and natures (Ogden & Hedley, 1980). Recent studies on the composition of the themes have led to the hypothesis that xenosomal amoebae (constituted by exogenous particles) can constitute relevant bio-indicators of the particulate diversity of the mineral, organic and biological environment in which they evolve . The main objective of the research carried out during this thesis is therefore to characterize the composition of the xenosomal amoebae and to evaluate their potential use as bioindicators of deposits of atmospheric particles. For this purpose, amoeba theae were analyzed in situ under natural conditions and after artificial deposits of allochtonous mineral particles. Several major conclusions can be drawn from this work: (1) The size of the mineral particles integrated in the xenosomal theca of Bullinularia indica Is similar to that of mineral particles transported into the atmosphere; (2) the mineral particles integrated into the thecs are stable silicates under the physico-chemical conditions prevailing in the peatlands, bryophytes and soils studied; (3) some minerals such as phlogopite, even when present in high concentrations, are never integrated by amoebae; (4) the combination of observations on the size, shape and nature of the particles used by xenosomic amoebae forms the basis for the use of tea amoeba for bioindication of recent or former atmospheric particulate diversity .

La nécessité d'une approche intégrée des pêches est actuellement largement affirmée, notamment par la FAO, en particulier dans le contexte des pêcheries artisanales tropicales. Ces pêcheries à petites échelles, souvent multi-spécifiques sont très importantes en termes d'emploi et de production, y compris pour la sécurité alimentaire. Néanmoins ces pêcheries et la biodiversité exploitées sont souvent marquées, d'une part, par le manque de données rendant difficile leur gestion dans le cadre d'une approche écosystémique, d'autre part, par la complexité des systèmes écologiques et économiques sous-jacents incluant interactions trophiques et techniques.Cette thèse contribue à la mise au point d'outils bioéconomiques adaptés aux petites pêcheries tropicales dans la perspective d'une gestion durable des pêches fondée sur l'approche écosystémique. Dans cette perspective, la pêcherie côtière en Guyane Française constitue un cas d'étude particulièrement fécond. La thèse propose ainsi des évaluations multi-critères, des modèles bioéconomiques complexes et des scénarios de gestion viable pour cette pêcherie.Dans un premier temps l'analyse statistique multi-variée suggère un statut global satisfaisant de la pêcherie en termes de durabilité. Cependant des différences de performance sont notées au sein de la pêcherie, notamment au niveau des zones frontalières. Aussi des améliorations dans le mode de gestion sont proposées. Ensuite, à travers la modélisation bioéconomique, les projections des différents scénarios de pêche montrent qu'à long terme le niveau d'exploitation actuel peut ne pas être en adéquation avec la future augmentation de la demande locale et qu'une perte de biodiversité peut avoir lieu. Un scénario dit de « co-viabilité » conciliant des objectifs à la fois écologique, économique et social, avec une probabilité de réalisation satisfaisante, est mis en exergue. Enfin, la comparaison des comportements optimaux en situation coopératif et non coopératif, montre dans quelle mesure la viabilité est favorisée quand les acteurs coopèrent. Au-delà du diagnostic apporté pour le cas d'étude, la méthode utilisée s'avère prometteuse dans le contexte des petites pêcheries tropicales, tandis que l'approche de « co-viabilité » permet de trouver les modalités d'exploitation dans le cadre de compromis entre durabilité écologique et socio-économique, ce que les principes de gestion halieutiques traditionnels ne permettent généralement pas. / The need for an integrated approach to fisheries is now widely affirmed, including the FAO, in particular in the context of tropical artisanal fisheries. These small-scale fisheries, often multispecies are very important in terms of production, employment and food security. However these fisheries and the exploited resources are often characterized by a lack of data making difficult their management within an ecosystem approach, and by the ecological and economic system complexities including trophic and technological interactions.This thesis aims to contribute to the development of bioeconomic tools for small tropical fisheries in a sustainable management perspective based on the ecosystem approach. In this perspective, the French Guiana coastal fishery constitutes an interesting case study. The thesis proposes multi-criteria evaluations, complex bioeconomic models and viable management scenarios for this fishery. At first, multivariate statistical analysis suggests a satisfactory overall status of the fishery in terms of sustainability. However, some performance differences are noted within the fishery, particularly at border areas. Also, management improvements are proposed. Then, through bioeconomic modeling, projections of different fishing scenarios show that, in the long term, the current exploitation level may not be consistent with the future increase of local demand and a loss of biodiversity may occur. A scenario called "co-viability" reconciling ecological, economic and social objectives, with a high probability of achievement is exhibited. Finally, the comparison of optimal behavior in cooperative and non-cooperative conditions, confirms that harvest levels are greater when actors do not cooperate. Furthermore, it is shown that the state of the ecosystem depends on the fishing strategies and the type of interaction between species. Beyond the diagnosis made for the case study, the method is promising in the context of small tropical fisheries, while the co-viability approach allows finding the exploitation conditions under which ecological and socio-economic sustainability are meet, what the conventional fisheries management generally do not allow.