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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Competitive interactions between young-of-the-year smallmouth bass (<i>Micropterus Dolomieu</i>) and round goby (<i>Apollonia melanostomus</i>)

Winslow, Christopher J. 12 November 2010 (has links)
No description available.
2

Estrutura filogenética de assembleias de árvores do Cerrado. Compreendendo a biogeografia e história evolutiva do bioma / Phylogenetic structure of Cerrado tree assemblages. Understanding the biogeography and the evolutionary history of the biome

Souza Neto, Advaldo Carlos de 04 March 2016 (has links)
Submitted by Cláudia Bueno (claudiamoura18@gmail.com) on 2016-07-13T20:52:05Z No. of bitstreams: 2 Tese - Advaldo Carlos de Souza Neto - 2016.pdf: 7882520 bytes, checksum: fc1dbbcc9d2125e1ceb756bd966db55f (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-07-14T13:02:47Z (GMT) No. of bitstreams: 2 Tese - Advaldo Carlos de Souza Neto - 2016.pdf: 7882520 bytes, checksum: fc1dbbcc9d2125e1ceb756bd966db55f (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-07-14T13:02:47Z (GMT). No. of bitstreams: 2 Tese - Advaldo Carlos de Souza Neto - 2016.pdf: 7882520 bytes, checksum: fc1dbbcc9d2125e1ceb756bd966db55f (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-03-04 / Understanding the processes that guide species distribution is a classic aim of Ecology. Several approaches were used to reach this objective. The use of phylogenetic data to elucidate and comprehend ecological patterns and processes has grown recently. However, the use of phylogeny as proxy to species traits, considering the premise that species phylogenetically closely related are functionally related, has been contested along the years. From these questions, several authors have thought about what is the best way to use the phylogenetic knowledge to better understand ecological and biogeographical patterns and processes. The Cerrado is the second largest biome of Brazil and has great biodiversity and many endemic species. The knowledge about the biome evolution has grown, but more studies still are necessary do deeply understand the origin of its biodiversity. Our aim was to use phylogenetic knowledge to try clarifying the evolutionary history of Cerrado biome. The first chapter brings a scientometric analysis of “Phylogenies and community ecology” paper by Webb et al. (2002). We conclude that the paper was very important to establish the “Ecophylogenetics” field, because even with a contested initial view, the work was important to bring the researchers attention about the use of phylogenies in ecological and evolutionary studies. The second chapter brings a phylogenetic approach to understand the Cerrado biome evolution and its relationship with other biomes surrounding it, using the Caesalpinioideae subfamily (Fabaceae) as model. In this chapter we observed that Cerrado biodiversity was originated by habitat shifting, which species from another biome, Caatinga in this case, can colonize a new environment and establish. However, some clades evolved in situ, diversifying in the Cerrado biome. The third chapter bring a deeper study on Cerrado evolution, using as model all trees that occur on Cerrado biome. In this chapter we studied the phylogenetic relationships among species that occur in different phytophisiognomies. We conclude that, although cerrado sensu stricto and cerradão be very similar, the other phytophysiognomies have independent evolutionary histories. Lastly, we conclude that phylogenetic knowledge is useful to understand historical and biogeographical processes. The vegetal biodiversity diversification of Cerrado was influenced by historical events like the C4 plants diversification and the uplift of Brazil Central shield. Besides, there are evidences that the Cerrado phytofisiognomies have independent evolutionary histories. The chapters add up previous studies to favour a better comprehension of Cerrado origin and evolution of its biodiversity, bringing new perspectives for future studies. / Entender os processos que norteiam a distribuição geográfica de espécies é um objetivo clássico da Ecologia. Diversas abordagens foram utilizadas para atingir essa meta. O uso de dados filogenéticos para a elucidação e compreensão de processos e padrões ecológicos tem crescido muito nos últimos anos. Entretanto o uso de filogenias para substituir características das espécies, usando a premissa de que espécies filogeneticamente mais próximas são funcionalmente próximas, vem sido contestado ao longo do tempo. A partir desses questionamentos, diversos autores têm pensado qual seria a melhor maneira de se usar o conhecimento filogenético para melhor compreender padrões e processos ecológicos e biogeográficos. O Cerrado é o segundo maior bioma brasileiro e possui uma grande biodiversidade e endemismo de espécies. O conhecimento acerca da evolução do bioma vem crescendo, mas ainda são necessários mais estudos para entender a fundo a origem dessa grande diversidade biológica. Este trabalho teve como objetivo utilizar os conhecimentos filogenéticos para tentar esclarecer a história evolutiva do bioma Cerrado. No primeiro capítulo temos uma análise cienciométrica do artigo “Phylogenies and community ecology” de Webb et al. (2002). Podemos concluir que o artigo foi muito importante para o estabelecimento do campo da “Ecophylogenetics”, pois mesmo apresentando uma visão inicial contestada o trabalho foi importante para chamar a atenção dos pesquisadores acerca da aplicação de filogenias em estudos ecológicos e evolutivos. No segundo capítulo usamos uma abordagem filogenética para compreender a evolução do bioma Cerrado e sua relação com os biomas vizinhos que o cercam, tendo como modelo a subfamília Caesalpinioideae (Fabaceae). Nesse capítulo observamos que a biodiversidade do bioma pode ter se originado por meio do processo de mudança de habitats, no qual espécies de outros biomas, em especial da Caatinga, conseguem colonizar o novo ambiente e se estabelecer. Entretanto, alguns clados passaram pelo processo de evolução in situ, tendo se diversificado dentro do bioma Cerrado. No terceiro capítulo, aprofundamos no estudo da evolução do bioma, tendo como modelo de estudo todas as espécies de árvore que ocorrem no Cerrado. Nesse capítulo estudamos mais a fundo as relações de proximidade filogenética entre as espécies que ocorrem as diferentes fitofisionomias do bioma, chegando à conclusão que, embora o cerrado sensu stricto e o cerradão sejam bastante similares, as demais fitofisionomias possuem histórias evolutivas independentes. Por fim, concluí-se a partir do trabalho, que o conhecimento filogenético é bastante útil para entender processos históricos e biogeográficos. A diversificação da biodiversidade vegetal do Cerrado sofreu influência de eventos tais como a diversificação de plantas C4 e o soerguimento do escudo do Brasil central. Além disso, existem evidências de que o bioma apresente fitofisionomias com histórias evolutivas distintas. Os capítulos somam-se aos demais estudos já realizados para fornecerem uma maior compreensão da origem e evolução da biodiversidade do bioma Cerrado, trazendo novas perspectivas para estudos futuros.
3

Comparaison de la structure des peuplements de poissons et des processus écologiques sous- jacents, entre les forêts de Cystoseires et des habitats structurellement moins complexes, dans l'Infralittoral rocheux de Méditerranée nord-occidentale / Comparison of fish assemblage structure and underlying ecological processes, between Cystoseira forests and less structurally complex habitats of North-Western Mediterranean rocky subtidal

Thiriet, Pierre 30 September 2014 (has links)
Dans l'Infralittoral rocheux méditerranéen, les algues brunes du genre Cystoseira forment des habitats structurellement complexes, dénommés forêts à Cystoseira. A cause de certaines activités anthropiques, ces forêts ont déjà disparu dans de nombreuses localités et sont en train de régresser dans d'autres. Elles ont été (sont) généralement remplacées par des habitats structurellement moins complexes de type brousse, gazon ou désert. Cette thèse a visé à estimer les possibles conséquences pour les poissons de la régression des forêts à Cystoseira et à identifier les processus écologiques en cause. Plusieurs approches complémentaires ont été employées : inventaires de macroalgues et de poissons, expériences de prédation et de sélection d'habitats en aquarium, analyses de composions isotopiques et de contenus stomacaux. Les densités de poissons proie et prédateur étaient plus importantes dans les forêts à Cystoseira que dans les habitats structurellement moins complexes. Cela peut résulter, au moins en partie, du rôle "refuge" de Cystoseira spp. qui induit (1) une plus faible mortalité des poissons proies et prédateurs dans les forêts, due à une plus grande disponibilité en abris et en nourriture, respectivement, (2) une immigration nette des poissons dans les forêts due à leur préférence pour cet habitat structurellement complexe. De plus, Cystoseira spp. pourrait être une importante source de matière organique pour l'écosystème. Ce potentiel rôle trophique mérite des études complémentaires. Ce travail suggère que la régression des forêts à Cystoseira est néfaste pour les poissons et souligne donc la nécessité de mieux gérer les activités humaines impactant Cystoseira spp. / In Mediterranean rocky subtidal, large brown algae belonging to the genus Cystoseira form structurally complex habitats, called Cystoseira forest. Due to anthropogenic stressors, Cystoseira forests disappeared from numerous localities in the Mediterranean Sea and are deteriorating in other localities. Cystoseira forests are usually replaced by structurally less complex habitats, such as shrublands, turfs and barren. This PhD aimed to assess putative consequences for fish of Cystoseira forest degradation, and to identify the underlying ecological processes. Multiple complementary approaches were used: macroalgae and fish field surveys, tank-based predation and habitat-choice experiments, stable isotopes and stomach contents analyses. Densities of prey and predatory fish were higher in Cystoseira forests compared to structurally less complex habitats. This may be due to the shelter role of Cystoseira spp. that induces (1) reduced mortality of prey and predatory fish in forests, due to high shelter and food availability, respectively, and (2) net immigration of fish into forests due to their preference for this structurally complex habitat. Moreover, Cystoseira spp. may be an important source of organic matter to the ecosystem. This possible trophic role deserves complementary studies. This work suggests that Cystoseira forest degradation are harmful to fish and from this perspective stresses the need to better manage human activities impacting Cystoseira spp.

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