La diadromie représente un cycle de vie qui implique obligatoirement des migrations entre la mer et l’eau douce. La diadromie s’est maintenue dans différentes lignées évolutives de poissons, mettant ainsi en évidence l’existence d’avantages adaptatifs comme la capacité à coloniser des milieux vierges ou de mieux exploiter la variabilité spatio-temporelle de l’environnement. Une hypothèse pour expliquer l’origine et le maintien de la diadromie postule que les migrations entre mer et rivière ont pour but de placer les individus dans le milieu qui favorisera la croissance avant la première reproduction. Une croissance en mer et une reproduction en rivière (anadromie) serait favorisée si la productivité primaire en eau douce est inférieure à celle des milieux marins environnants tandis que la situation inverse (catadromie ; reproduction en mer, croissance en rivière) est attendue quand le différentiel de productivité est en faveur des eaux douces. Les résultats de notre étude réalisée à l’échelle du globe confirment cette hypothèse et montrent également que les poissons diadromes se trouvent majoritairement dans des rivières à faible richesse spécifique et/ou ouvertes à la colonisation après le retrait des glaciers au Quaternaire. Leur capacité à coloniser de nouveaux milieux permet aux diadromes d’être très présents sur les îles océaniques. Si la biodiversité sur les îles océaniques a été largement étudiée, très peu d’études ont porté sur les poissons d’eau douce qui s’y trouvent. Notre étude des peuplements de poissons des îles polynésiennes confirme la généralité d’un modèle proposé pour les faunes terrestres prédisant une relation en dôme entre richesse spécifique et âge de l’île. Nos résultats montrent également que la richesse diminue avec la distance au centre de biodiversité le plus proche et augmente avec l’altitude maximale de l’île.Malgré leur succès évolutif, les poissons diadromes se révèlent très vulnérables face aux activités humaines (surexploitation, pollution de l’eau, barrages…). De ce fait, de nombreuses espèces sont classées comme vulnérables par l’IUCN. Paradoxalement, notre étude sur les caractéristiques biologiques et écologiques des espèces qui se sont éteintes récemment à l’échelle du globe n’identifie pas la diadromie comme un facteur aggravant. Cette étude montre que le critère biologique principal menant à l’extinction est l’endémisme et une aire de distribution géographique restreinte. Bien que souvent en déclin, beaucoup d’espèces diadromes ont jusqu’ici échappé à l’extinction du fait de leur aire de distribution initiale de grande taille, résultat probable de leur grande capacité de dispersion. Un très bon exemple est l’esturgeon européen, Acipenser sturio, initialement largement distribué en Europe mais qui après un fort déclin à partir de 1850 ne se reproduit plus que dans le seul bassin de la Garonne. Pour mieux suivre le déclin de cette espèce au cours du temps, nous avons étudié sa distribution avant 1850 à l’aide de données archéozoologiques. L’analyse de ces données suggère une diminution des populations très ancienne, initiée il y a 2500 ans. A l’aide de températures passées reconstituées, nous avons montré que des températures élevées expliquent en partie l’occurrence d’esturgeons dans les sites archéologiques mais sans contribuer à expliquer son déclin. Ces résultats suggèrent un impact de l’homme précoce sur les populations d’esturgeons. Cette thèse a permis de synthétiser les connaissances sur les poissons diadromes concernant leur distribution géographique à diverses échelles de temps et d’espace, et de contribuer à une meilleure compréhension de leur diversité et de leur vulnérabilité. / Diadromous species exhibit a life-cycle implying migrations between freshwater and ocean. Diadromy is observed in many fish lineages suggesting that adaptive traits are associated with this strategy such as better dispersal ability and more efficient tracking of the spatio-temporal variability of the environment. One of the hypotheses that have been put forward to explain the evolution and persistence of diadromy states that the purpose of migrations is to select environmental conditions that will optimize pre-reproductive growth. Growing at sea and reproducing in river (anadromy) is supposed to be favored when freshwater primary productivity is lower in freshwater than in the nearby sea. The reverse (growing in freshwater, reproducing in ocean; catadromy) is expected when productivity is higher in sea than in freshwater. According to our study, conducted at a global scale, this hypothesis holds true. In addition it is shown that diadromous species are overrepresented in species poor rivers and/or in those that have been open to colonization after the retreat of glaciers after the last glacial maximum. Because of their dispersal ability, diadromous species are also over-represented on oceanic islands. Biodiversity on islands is classical topic of biogeography but yet few studies have dealt with freshwater fishes. In our study of fish communities from the Polynesian islands, we demonstrate the generality of a model initially built to explain terrestrial biodiversity on oceanic islands. As predicted by this model, species richness peaks at peaks at intermediate island age. Also revealed by our results are a positive relationship between island elevation and species richness and a decrease in species richness as the distance from the nearest biodiversity hotspot increases. Diadromy has been a successful strategy over geologic times but in face to human activities it seems to contribute to extinction proneness, as exemplified by the numerous diadromous species red listed by IUCN. Paradoxically, our study about the biological and ecological traits shared by the freshwater fishes that have been recently globally extinct does not suggest that diadromy has been a major factor. This study points to endemism and restricted geographic range size as the major determinants of extinction. It seems that because of their dispersal abilities, diadromous species tend to have widespread historical distributions and, even if many species are declining, this prevented most of them from being entirely extirpated. This is well exemplified by the European sturgeon (Asipenser sturio), formerly widely distributed over Europe and now restricted to one reproducing population in the Garonne River, because of dramatic population collapses after 1850. To have a better idea of the fate of this species before 1850, we analyzed archaeozoological records. According to our analyses, sturgeons started to decline a long time ago, about 2500 years ago. Using reconstructed past temperatures, our analyses show that a high temperature increases the probability of finding this species in archeological remains but cannot explain entirely the observed decline. This suggests that human activities impacted sturgeon populations well before the industrial revolution. This thesis by synthesizing species occurrence data over different spatial and temporal scales contributed to a better knowledge about the diversity and vulnerability of diadromous fishes.

As comunidades bentônicas concentram a maior parcela da biodiversidade marinha e constituem um elemento essencial da estrutura dos ecossistemas marinhos como um todo. São vários os fatores que influenciam na dinâmica bentônica, como interações competitivas, reprodução, aporte de nutrientes, temperatura, entre outros. Esses fatores regem o funcionamento da comunidade e alterações desses padrões, como pesca e poluição, podem induzir mudanças de fase. Ainda assim, é possível que mudanças de fase façam parte da dinâmica natural, a partir de fenômenos que agem em escalas de tempo maiores. Por esse motivo, torna-se bastante difícil indicar quais fatores podem suscitar mudanças lentas que culminem em diferenças importantes na estrutura das comunidades. Portanto, se fazem necessários estudos de variações temporais de longo prazo para melhor entendimento desses padrões naturais e das mudanças nesses padrões, que podem afetar o funcionamento e a resiliência do ecossistema. Esse tipo de estudo ainda é escasso para ilhas oceânicas brasileiras, sendo mais frequentes estudos de caracterização e de curto prazo. Dada a importância desse tipo de pesquisa, o presente trabalho é o primeiro para a comunidade bentônica recifal de uma série de estudos de longo prazo na ilha da Trindade, e integra o \"Programa de Pesquisas Ecológicas de Longa Duração das Comunidades Recifais das ilhas Oceânicas Brasileiras\" (PELD-ILOC), com objetivo central de analisar a dinâmica espaço-temporal da comunidade bentônica da ilha da Trindade e descrever sua composição entre os anos de 2013 e 2017. Para tal, foram demarcados quatro sítios em torno da ilha, com três transecções de 20 metros de comprimento em cada um, amostrando uma transecção por profundidade com 10 fotoquadrados em cada transecção. A cobertura bentônica foi avaliada por meio do software CPCe, com identificação dos organismos até o menor nível taxonômico possível, sendo posteriormente agrupados em grupos morfofuncionais. No geral, a comunidade bentônica da ilha da Trindade no período analisado foi dominada por macroalgas (Caulerpa sp., Canistrocarpus cervicornis e Jania sp.), turf e algas calcárias crostosas (Peyssonnelia sp.) e apresenta diferença significativa entre sítios e anos, porém não apresenta diferenças significativas entre as profundidades analisadas. Apesar do dinamismo natural dessas comunidades, foi possível observar diminuição da abundância de organismos bioconstrutores em 2016, que pode ter ocorrido devido ao El-Niño registrado no mesmo período. O ano de 2017 foi o que menos se assemelhou com os demais, apresentando aumento na riqueza, maior diversidade, maior relação entre sítios, grande crescimento na abundância de algas calcárias crostosas e mudança de dominância dentro do grupo de macroalgas, com a substituição da macroalga Caulerpa sp. pela macroalga calcária articulada Jania sp.. Para explicar essas alterações, assim como suas consequências, é necessária a continuação do presente monitoramento, incluindo novas abordagens e metodologias, integrando análises de variáveis físico-químicas e padronização nos estudos para possíveis comparações, o que ajudaria a compreender melhor o comportamento da comunidade bentônica insular oceânica brasileira no geral e responder questões que só podem ser elucidadas a longo prazo. / Benthic communities host a major fraction of the marine biodiversity, being an essential component in the structure of marine ecosystems. There are several factors that influence the benthic dynamics, such as competitive interactions, reproduction, nutrient, temperature, etc. These factors control the functioning of the community and changes in these patterns can induce phase shifts. Nevertheless, it is possible that phase shifts are part of the natural dynamics, from phenomena that act on larger time scales. So, it is very difficult to indicate which factors can lead to slow changes that affect the structure of communities. Therefore, studies of long-term temporal variations are needed to better understand changes in those patterns that may affect the functioning and resilience of the ecosystem. This kind of study is still scarce for Brazilian oceanic islands, with more frequent characterization and short-term assessments. Hence, the present work is the first one for the benthic reef community of a series of long-term studies in the Trindade Island, and integrates the \"Long-term Ecological Research Program of the Reef Communities of the Brazilian Oceanic Islands\" (in Portuguese Programa de Pesquisas Ecológicas de Longa Duração das Comunidades Recifais das Ilhas Oceânicas Brasileiras - PELD-ILOC). The present study describes and does a spatio-temporal analysis of the reef benthic community of Trindade Island, assessing the substrate cover dynamics of four sites from 2013 to 2017. Each site was sampled at three depth ranges, with three transects and ten photoquadrats in each transect. Benthic coverage was analyzed using the CPCe software, with organisms identified to the lowest possible taxonomic level, and later grouped into morphofunctional groups. In general, the benthic community of Trindade Island during the analyzed period was dominated by macroalgae (Caulerpa sp., Canistrocarpus cervicornis and Jania sp.), turf and crustose coralline algae (Peyssonnelia sp.) The results showed significant changes among sites and years, however did not show significant changes among depths. Despite the natural dynamism of these communities, it was possible to observe a decrease in the abundance of bioconstructors in the 2016 expedition, which may have occurred because to El-Niño during the same period. The year 2017 was the most different when compared to others years, with an increase in species richness, but also greater diversity, greater similarity among sites, and a pronounced growth in the abundance of crustose coralline algae. In the same year a change in the dominant species was also observed, with the substitution of the macroalgae Caulerpa sp. by the articulated coralline algae Jania sp.. It is important to continue the present monitoring in order to determine the main causes and consequences of these structural changes, including new approaches and methodologies, integrating abiotic variables and standardization in the studies for possible future comparisons, which would help to better understand the behavior of the Brazilian insular benthic oceanic community in general and answer questions that can only be elucidated in the long term.

Nasutitermes corniger tends to construct its distinctive, conspicuous nests at the bases of trees in the northern West Indies versus well above ground on trunks or branches in Trinidad & Tobago and further south. By means of data from 32 localities from the Equator to 17° north latitude, we describe the geographic pattern of nest-height variation. The localities are from both continental areas (mainland and continental islands) and oceanic islands. The latter are all to the north of the former. If nest-height variation is mainly or solely due to abiotic (climatic) factors, a more or less monotonic south–north decline is predicted. If it is mainly due to biotic factors, a change in the trend is expected at a distinct latitudinal transition. The data show an overall tendency for nest height to decrease further from the Equator. However, there is a distinct change in the slope, consistent with the biotic hypothesis. Against expectation, this does not occur between Tobago (continental island) and Grenada (oceanic island) but between Venezuela (continental mainland) and Trinidad (continental island). The biotic factors affecting nest-site in this species are not known. However, the data are consistent with the hypothesis that the species involved are affected by biotic relaxation during the several millennia since Trinidad and Tobago isolated from the mainland.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第18660号 / 農博第2089号 / 新制||農||1028(附属図書館) / 学位論文||H26||N4883(農学部図書室) / 31574 / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 井鷺 裕司, 教授 北島 薫, 教授 北山 兼弘 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

A Ilha da Trindade está localizada a aproximadamente 1150 km da costa de Vitória-ES, é uma das ilhas oceânicas brasileiras e está sob o domínio da Marinha do Brasil. Desde o início de sua ocupação sofreu algumas influências antrópicas, como a derrubada de árvores e a introdução de animais (porcos e cabras). Os metais oriundos da costa ou de navios que passam pela região, estão em destaque entre os contaminantes ambientais que podem alterar o ecossistema da ilha. Dessa forma, o objetivo desse trabalho foi quantificar Al, As, Cd, Cu, Fe, Mn, Ni, Pb, Se, Zn e Hg em 300 amostras, compostas por músculo de duas espécies de caranguejo e de fígado e músculo de peixes (duas espécies) e aves (três espécies). Foram verificadas se existiam relações entre parâmetros biológicos (sexo, comprimento, peso), diferenças entre tecidos e entre os períodos de coleta. Nos caranguejos a concentração de Fe em G. lagostoma, e Zn em G. grapsus, foram maiores nos meses mais quentes, nos quais a atividade biológica é maior, sendo uma possível causa para maiores concentrações. Diferentemente dos caranguejos, a espécie M. niger (peixe) apresentou maiores concentrações (Al no músculo e Fe e Zn no Fígado) nos meses mais frios, as concentrações em peixes envolvem muitos fatores além da sazonalidade. Para ambas as espécies de peixes as concentrações de Fe e Zn foram maiores no fígado, assim como para P. arminjoniana (ave) as concentrações de Cu, Fe e Zn também foram maiores no fígado, como era esperado, pois, o fígado é um tecido com grande capacidade de acumular poluentes. Alguns elementos apresentaram correlações com o peso e/ou comprimento, porém todas muito baixas, com exceção do Zn em G. grapsus. Todas as análises de Hg realizada ficaram abaixo do limite de quantificação do método (17,7 µg kg-1). Os metais e semimetais apresentaram resultados semelhantes a estudos desenvolvidos em outras regiões. / The Trindade Island is located approximately 1150 km from the coast of Vitória-ES, is one of Brazilian oceanic islands and is under the control of the Brazilian Navy. At the time the occupation began the island suffered some anthropogenic influences, such as the removal of trees and the animals introduction (pigs and goats). Metals originating from the shore or from ships passing through the region, are highlighting among the environmental contaminants that can change the ecosystem of the island. So the aim of this study was to quantify Al, As, Cd, Cu, Fe, Mn, Ni, Pb, Se, Zn and Hg in three hundred samples of muscle of two species of crab and liver and muscle of fish (two species) and seabirds (three species). The relationships between biological parameters (sex, length, weight), differences between tissues and between sampling periods were checked. The concentration of Fe, G. lagostoma (crab), and the Zn, in G. grapsus (crab), showed higher concentrations in the warmer months, in which biological activity is greater, being a possible cause for higher concentrations. Different from crabs, the species M. niger (fish) presented higher concentrations (Al in the muscle and Fe and Zn in the liver) in the colder months, concentrations in fish involve many factors besides the seasonality. For both species of fish concentrations of Fe and Zn were higher in the liver as well as for P. arminjoniana (seabird) concentrations of Cu, Fe and Zn were higher in the liver, like was expected, because the liver is a tissue with a great capacity to accumulate pollutants. Some elements showed correlations with the weight and/or length, but all very low, with the exception of Zn in G. grapsus. All Hg analyzes performed were below the method quantification limit (17.7 µg kg-1). The metals and semimetals showed similar results to studies conducted in other regions.

Submitted by (edna.saturno@ufrpe.br) on 2017-02-23T13:49:46Z No. of bitstreams: 1 Ilka Siqueira Lima Branco Nunes.pdf: 2141818 bytes, checksum: 9aa7bf11d864f1e1ce580f338251fe3c (MD5) / Made available in DSpace on 2017-02-23T13:49:46Z (GMT). No. of bitstreams: 1 Ilka Siqueira Lima Branco Nunes.pdf: 2141818 bytes, checksum: 9aa7bf11d864f1e1ce580f338251fe3c (MD5) Previous issue date: 2015-05-29 / The south stingray is commonly captured as by-catch in different fisheries, not only in Brazil but also in some parts of South America, and due to the deficiency of available data, there is now a considerable deficit of information to evaluate the population status of the specie. In this context, the main goal of this study was to investigate aspects related to the ecology of the D. americana along the coast of the metropolitan area of Recife, from capture data and acoustic monitoring, and in the Biological Reserve of Atol das Rocas, from observation and movement analysis. On the coast of Recife CPUE´south stingray was higher in Boa Viagem / Piedade (0.33) than in Paiva (0.26). The average monthly CPUE on the beach of Boa Viagem / Piedade was higher in May, while on the beach of Paiva the highest value occurred in June. The annual CPUEs, to the beaches in combination, were higher at the research beginning in 2004 and 2005. Of the 85 specimens, it was possible to identify the sex in 17 animals, of which 16 were females, with DW ranging between 79.00 and 152.00 cm (124.63 ± 20.86), DL between 94.00 and 142.00 cm (113.08 ± 14.14), and TL between 97.00 and 255.00 cm (188.31 ± 54.97); and only one was male, with DW 87.00 cm. Throughout the research was also recorded the occurrence of a food item (Dasyatis marianae) unusual, never described before for D. american diet. The evaluation of the detection from the acoustic monitoring on the reef coastline, in relation to the 24 hour cycle indicated that the majority of the detections occurred over night (96.4%) (X² = 144.857; P <0.0001). The TAH values were higher in the years 2003 (0.76 ± 1.51) and 2008 (1.55 ± 1.76), observing, between 2009 (0.15 ± 0.42) and 2013 ( 0.21 ± 0.57), values consistently lower. The significant decrease of species sightings within the Rocas Atoll raised the possibility of there being a natural population decline in the region. The vertical habitat use pattern for the D. americana showed a strong preference for both tagged stingrays (91.4% and 86.3%, respectively) by hot water (above 28 ° C) and shallow (depths up to 5m) of Rocas Atoll over the monitoring period. The results showed that low depth areas as one of the essential habitats for specie inside to Rocas Atoll. Finally, it is essential that greater efforts are seeking in employees the continuation of an adequate monitoring of their populations in coastal and island waters. / A raia prego é comumente capturada como fauna acompanhante em diferentes pescarias, não apenas no Brasil mas também em grande parte da America do Sul, e devido à deficiência dos dados disponíveis, existe hoje um considerável déficit de informações que permitam avaliar o status populacional da espécie. Nesse contexto, o presente estudo teve como objetivo investigar aspectos relacionados à ecologia da D. americana, ao longo do litoral da região metropolitana do Recife, a partir de dados de captura e monitoramento acústico, e na Reserva Biológica do Atol das Rocas a partir de análises de avistagem e movimentação. No litoral de Recife a CPUE das raias prego foi maior em Boa viagem/Piedade (0,33) do que no Paiva (0,26). A CPUE média mensal na praia de Boa Viagem/Piedade foi maior no mês de maio, enquanto que na praia do Paiva o maior valor ocorreu em junho. As CPUEs anuais para as praias de forma combinada foram maiores no início da pesquisa, nos anos de 2004 e 2005. Dos 85 exemplares, foi possível a identificação do sexo em 17 animais, dos quais 16 eram fêmeas, com LD variando entre 79,00 e 152,00 cm (124,63 ± 20,86), CD entre 94,00 e 142,00 cm (113,08 ± 14,14), e CT entre 97,00 e 255,00 cm (188,31 ± 54,97); e apenas um era macho, com LD de 87,00 cm. Ao longo da pesquisa foi registrada ainda a ocorrência de um item alimentar (Dasyatis marianae) não usual, jamais antes descrito para dieta da D. americana. A avaliação das detecções do monitoramento acústico no litoral de Recife, em relação ao ciclo de 24 horas indicou que a maior parte das detecções ocorreram ao longo do período noturno (96,4%) (X²= 144,857; P< 0,0001). Os valores de TAH foram maiores entre os anos de 2003 (0,76 ± 1,51) e 2008 (1,55 ± 1,76), observando-se, entre 2009 (0,15 ± 0,42) e 2013 (0,21 ± 0,57), valores consistentemente mais baixos. A diminuição significativa das avistagens da espécie no interior do Atol das Rocas suscita a possibilidade de estar existindo um declínio natural da população na região. O padrão de uso do habitat vertical para a D. americana mostrou uma forte preferência, para ambas as raias marcadas (91,4% e 86,3%, respectivamente), pelas águas quentes (acima dos 28°C) e rasas (profundidades de até 5m) do Atol das Rocas, ao longo do período do monitoramento. Os resultados evidenciaram que as áreas de baixa profundidade como um dos habitas essenciais para espécie no Atol das Rocas. Por fim, é imprescindível que maiores esforços sejam empregados em busca da continuação de um adequado monitoramento de suas populações em águas costeiras e insulares.

Oceanic islands have been used as model systems for studies of evolution and speciation as the range of island sizes coupled with their known geological chronosequence make them ideal systems for the study of spatial and temporal variations in species diversity and distributions. These processes also occur on continental islands and mainland habitats but features of oceanic islands, notably their clearly delimited boundaries, natural isolation and simple geological composition make them more amenable to study. The perched dune lakes of Fraser Island, Australia share many of the properties of oceanic islands. The naturally isolated formation of the perched lakes, clearly delimited boundaries of the freshwater habitat and phase difference compared to the surrounding, terrestrial environment have significant implications for the biota these lakes support. Inhabitants of the perched dune lakes consist of the aquatic and semi-aquatic descendents of colonisers that were able to traverse a land barrier and survive in the oligotrophic, acidic waters over subsequent generations. Barriers to ongoing gene flow among lake populations, are however likely to be different for species with different life history characteristics. I therefore sought to assess the effects of three different life history characteristics on post-colonisation interpopulation gene flow. A representative species was selected to represent one of each of the following life history characteristics: * Aquatic species confined to lake for entire life cycle - freshwater shrimp Caridina indistincta. * Semi-aquatic species capable of terrestrial dispersal - freshwater turtle Emydura krefftii. * Semi-aquatic species capable of aerial dispersal - odonate Orthetrum Boumiera. 137-250 individuals were sampled per species across six lakes separated by 1-6km. Regions of the mitochondrial genome were targeted and molecular screening methods developed and employed to assess the relative levels of post-colonisation gene flow among lake populations. Parsimony analysis of the 25 unique haplotypes identified in the species with no apparent inter-lake dispersal mechanism, the freshwater shrimp Caridina indistincta, demonstrated that there was no sharing of derived haplotypes among lake populations. Star shaped genealogies were identified in four lake populations indicative of a population expansion and mismatch distribution analysis confirmed a recent population expansion estimated to have occurred no more than 200,000 years ago. This demonstrates that each of the perched dune lakes was colonised by C.indistincta soon after their inception but that no ongoing gene flow among lake populations has occurred. The population genetic structure of the species assessed which is capable of terrestrial dispersal suggests that although this species of freshwater turtle, Emydura krefftii, is capable of overland dispersal, gene flow among lake populations is limited. Even at the small spatial scale examined in this study, E.krefftii populations displayed a pattern of isolation by distance (r=0.854, p&lt0.03). Nested clade analysis also suggested a pattern of restricted gene flow with some long distance dispersal in recent times with long distance dispersal and a possible range expansion occurring historically. The species examined in this study that displayed the most extensive gene flow among lake populations was the dragonfly Orthetrum boumiera. No relationship was found between genetic and geographic distance (r= -0.0852, p&gt0.05) and nested clade analysis could not identify a geographical association among haplotypes, indicative of panmixia. While larval life stages of this species are fully aquatic, the winged adult stages of this species appear to be connecting seemingly isolated lake populations, at least at the spatial scale examined here. The results of this study have demonstrated that these perched dune lakes provide 'island like' models for recent biogeographic processes. The pattern of colonisation and subsequent diversification identified in these populations takes the form of insitu 'genetic radiations' with those populations that are isolated forming monophyletic clades endemic to a single lake. The genetic diversity and endemism identified in this study has occurred over much smaller temporal (&lt500,000 years) and spatial (&lt6.5km) scales than in studies of oceanic island fauna. However, the mode of formation of the perched dune lakes and the implications that their natural isolation and abiotic genesis have for the evolution of colonisers of these unique habitats has resulted in them being analogous to true oceanic islands.

A Ilha da Trindade está localizada a aproximadamente 1150 km da costa de Vitória-ES, é uma das ilhas oceânicas brasileiras e está sob o domínio da Marinha do Brasil. Desde o início de sua ocupação sofreu algumas influências antrópicas, como a derrubada de árvores e a introdução de animais (porcos e cabras). Os metais oriundos da costa ou de navios que passam pela região, estão em destaque entre os contaminantes ambientais que podem alterar o ecossistema da ilha. Dessa forma, o objetivo desse trabalho foi quantificar Al, As, Cd, Cu, Fe, Mn, Ni, Pb, Se, Zn e Hg em 300 amostras, compostas por músculo de duas espécies de caranguejo e de fígado e músculo de peixes (duas espécies) e aves (três espécies). Foram verificadas se existiam relações entre parâmetros biológicos (sexo, comprimento, peso), diferenças entre tecidos e entre os períodos de coleta. Nos caranguejos a concentração de Fe em G. lagostoma, e Zn em G. grapsus, foram maiores nos meses mais quentes, nos quais a atividade biológica é maior, sendo uma possível causa para maiores concentrações. Diferentemente dos caranguejos, a espécie M. niger (peixe) apresentou maiores concentrações (Al no músculo e Fe e Zn no Fígado) nos meses mais frios, as concentrações em peixes envolvem muitos fatores além da sazonalidade. Para ambas as espécies de peixes as concentrações de Fe e Zn foram maiores no fígado, assim como para P. arminjoniana (ave) as concentrações de Cu, Fe e Zn também foram maiores no fígado, como era esperado, pois, o fígado é um tecido com grande capacidade de acumular poluentes. Alguns elementos apresentaram correlações com o peso e/ou comprimento, porém todas muito baixas, com exceção do Zn em G. grapsus. Todas as análises de Hg realizada ficaram abaixo do limite de quantificação do método (17,7 &#181;g kg-1). Os metais e semimetais apresentaram resultados semelhantes a estudos desenvolvidos em outras regiões. / The Trindade Island is located approximately 1150 km from the coast of Vitória-ES, is one of Brazilian oceanic islands and is under the control of the Brazilian Navy. At the time the occupation began the island suffered some anthropogenic influences, such as the removal of trees and the animals introduction (pigs and goats). Metals originating from the shore or from ships passing through the region, are highlighting among the environmental contaminants that can change the ecosystem of the island. So the aim of this study was to quantify Al, As, Cd, Cu, Fe, Mn, Ni, Pb, Se, Zn and Hg in three hundred samples of muscle of two species of crab and liver and muscle of fish (two species) and seabirds (three species). The relationships between biological parameters (sex, length, weight), differences between tissues and between sampling periods were checked. The concentration of Fe, G. lagostoma (crab), and the Zn, in G. grapsus (crab), showed higher concentrations in the warmer months, in which biological activity is greater, being a possible cause for higher concentrations. Different from crabs, the species M. niger (fish) presented higher concentrations (Al in the muscle and Fe and Zn in the liver) in the colder months, concentrations in fish involve many factors besides the seasonality. For both species of fish concentrations of Fe and Zn were higher in the liver as well as for P. arminjoniana (seabird) concentrations of Cu, Fe and Zn were higher in the liver, like was expected, because the liver is a tissue with a great capacity to accumulate pollutants. Some elements showed correlations with the weight and/or length, but all very low, with the exception of Zn in G. grapsus. All Hg analyzes performed were below the method quantification limit (17.7 &#181;g kg-1). The metals and semimetals showed similar results to studies conducted in other regions.

Les mécanismes à l'origine de la mise en place de l'isolement reproducteur sont relativement peu étudiés dans les radiations adaptatives insulaires. Selon la théorie de la spéciation écologique, l'isolement reproducteur résulte de la sélection divergente agissant sur des populations écologiquement différentes. Par leurs caractéristiques uniques, les îles océaniques constituent des systèmes idéals pour étudier le rôle des facteurs écologiques dans la diversification des lignées endémiques. Le rôle de l'habitat et des pollinisateurs dans la restriction des flux géniques inter et intraspécifique est examiné chez le faham (Jumellea rossii et J. fragrans), une orchidée endémique des Mascareignes. Pour ce faire, les patrons de différenciation phénotypique (traits floraux morphologiques et chimiques), environnementale (habitat, altitude, climat) et génétique (microsatellites nucléaires) ont été confrontés. À l'échelle intraspécifique, les résultats montrent que les flux de gènes sont principalement limités par les différences environnementales entre habitats sans rôle évident des pollinisateurs. A l'échelle interspécifique, outre les variations d'habitat, le changement de pollinisateur semble expliquer l'absence de flux de gènes. Dans le cadre du continuum de spéciation chez le faham, l'isolement reproducteur évoluerait en premier lieu en réponse à l'adaptation aux différents habitats, puis serait renforcé par l'adaptation à différents pollinisateurs. La révision de la taxinomie du clade et les priorités en terme de conservation sont également discutées. / Mechanisms responsible for the establishment of reproductive isolation are little studied in island adaptive radiations. According to the theory of ecological speciation, reproductive isolation results from the ecologically-based divergent selection. By their unique characteristics, oceanic islands are ideal systems to study the role of ecological factors in the diversification of endemic lineages. This study focuses on the role of habitat and pollinators in restricting inter and intraspecific gene flow between populations of faham (Jumellea spp.), an orchid endemic to Mascarene Islands. To do this, patterns of phenotypic differentiation (floral traits), environmental differentiation (habitat, altitude, climate) and genetic differentiation (nuclear microsatellites) were compared. At the intraspecific level, the results show that gene flow restriction is mainly due to the colonization of different habitat types with no obvious role of pollinators. At the interspecific level, in addition to the role of habitat, pollinator shift seems to explain effective complete reproductive isolation. By placing these results into the continuum of speciation, it appears that reproductive isolation evolve initially in response to adaptation to different habitats and, in a second phase, would be enhanced by pollinator-driven divergent selection. Operationally, this study reviews the taxonomy of faham and proposes to define management units and priorities in terms of conservation.