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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.
31

Banco de sementes autóctone e alóctone, resgate de plantas e plantio de vegetação nativa na fazenda Intermontes, município de Ribeirão Grande, SP. / Autochthonous and Allochthonous seed bank, seedling rescue and native vegetation planting at Intermontes farm, Ribeirão Grande-SP- Brazil.

André Gustavo Nave 27 April 2005 (has links)
O acúmulo significativo de conhecimento sobre a ecologia de restauração nos últimos anos tem conduzido a mudanças na orientação dos programas de manejo e restauração florestal. A escolha ou criação de um modelo de restauração é um processo em constante aprimoramento, exigindo a necessidade de estudos que não apenas diminuam os custos envolvidos, mas também, que garantam a efetividade do objetivo proposto. Neste sentido, este trabalho testa novas metodologias de restauração visando a obtenção de informações técnicas sobre: A) a expressão do banco de sementes autóctone e alóctone na restauração florestal de diferentes situações de degradação antrópica.; B) o resgate de plântulas e indivíduos de espécies arbustivo-arbóreas regenerantes; C) a eficiência de um modelo de plantio que utiliza conceitos de Preenchimento e Diversidade e; D) a evolução da paisagem. Para análise dos bancos de sementes autóctone e alóctone foram feitos levantamentos da densidade e das espécies arbustivo-arbóreas regeneradas. No resgate de indivíduos de espécies arbustivo-arbóreas regenerantes, as plântulas e indivíduos jovens foram resgatadas em uma floresta e levadas para adapatação em viveiro, onde tiveram seus indivíduos e espécies contabilizados em termos de densidade e sobrevivência. No modelo de plantio estudado, as espécies foram reunidas em grupos de Preenchimento e Diversidade e tiveram a cobertura de copa de cada indivíduo quantificada. A evolução da paisagem foi realizada através de fotointerpretação e principalmente checagem de campo periódica. Os principais resultados dessas metodologias foram: A) As situações identificadas na Fazenda Intermontes apresentaram diferentes expressões de regeneração natural em função do número de indivíduos germinados banco de sementes autóctone. O aproveitamento dessa expressão poderá ser realizado através de metodologias diferenciadas de restauração para cada situação estudada: B) No estudo do Banco de sementes alóctone, a densidade dos indivíduos germinados se foi de 409.334 indivíduos/ha, revelando a possibilidade de uso no programa de restauração. Os indivíduos arbóreos apresentaram na área adubada um acréscimo de 137,3 % em sua altura média em relação aos indivíduos da área não adubada. C) No resgate de plântulas e indivíduos de espécies arbustivo-arbóreas regenerantes, a densidade dos indivíduos foi muito próxima para as duas épocas do ano, sendo 38.700 ind./ha e 37.900 ind./ha, mas com uma diferença significante para os indivíduos sobreviventes que apresentaram 16.500 ind./ha e 26.600 ind./ha para os meses de julho e dezembro de 2002, respectivamente. A técnica de resgate utilizada se mostrou viável uma vez que foi possível alcançar até 70,9% de sobrevivência para os indivíduos resgatados; D) No estudo sobre o modelo de plantio foram amostrados 143 espécies, demonstrando que a função do grupo da diversidade vem sendo mantida e aumentando as chances de efetivação dos processos de sucessão. Os resultados mostraram que o grupo de Preenchimento apresentou-se com uma porcentagem de cobertura significativamente maior que a do grupo de Diversidade, sendo 73,6% e 83,3% para 1,5 e 2,5 anos respectivamente. / Significant accumulation of know-how about restoration ecology has been changing forest restoration management programs’ trends during the last years. Choosing or elaborating a restoration model is a process that requires constant improvement and ecological studies that not only reduces the costs involved but also warrants the achievement of the aimed proposal. This study explores new restoration methodologies, searching for technical information about: A) autochthonous and allochthonous seed bank expression on forest restoration at different situations degraded by anthropogenic disturbances; B) seedlings and woody growing individuals rescue; C) efficiency of a planting model based on fulfillment and diversity concept; D) landscape development. The autochthonous and allochthonous seed bank were analyzed through regenerating woody species and density scouting. For the rescue of regenerating woody species, seedling and young individuals were taken from a forest and transferred to a plant nursery for adjustment, where number and species were counted regarding density and survival. In this studied planting model, species were organized and gathered into a fulfillment or diversity group, and each individual had its crown area quantified. Landscape development was analyzed by photointerpretation and specially by periodical field checking. Results from these methodologies showed that: A) Identified degraded situations at Intermontes farm displayed distinguished natural regeneration expression, influenced by the number of germinated seeds of the autochthonous seed bank. Advantage can be taken from these different outcomes by using distinct restoration methodologies for each studied situation. B) For the autochthonous seed bank study, germinated seed density was 409,334 ind./ha, indicating its potential role on restoration programs. Woody individuals at fertilized sites had a medium height enhancement of 137,7% when compared to those at non fertilized sites. C) For seedlings and woody growing individuals rescue, individual density was similar for both seasons (38700ind./ha and 37900ind./ha) but significantly distinct for individual survivor, with values of 16500ind./ha for July and 2600ind./ha for December. Rescue technique turned out to be a viable possibility since it achieved survival of 70,9% for rescued individuals. D) This planting model study registered 143 species, indicating that the diversity group’s role has been maintained and enhances the chance of successional process success. The fulfilling group had a significant higher percentage of crown area than the diversity group, with 73,6% and 83,3% for 1,5 and 2,5 years, respectively.
32

Analyse und olfaktorische Steuerung bast- und holzbesiedelnder sowie diese natürlich regulierender zoophager Insekten an Laubbäumen als Grundlage für ein zukunftsfähiges und nachhaltiges Risikomanagement

Wehnert, Michael 24 February 2014 (has links)
Naturnahe Verfahren im Management bast- und holzbesiedelnder Insekten basieren auf der Ausnutzung olfaktorischer Reaktionen dieser Insekten und teilweise auch derer Antagonisten auf Semiochemikalien käferbürtigen und baumbürtigen Ursprungs. Verfahren, die im Rahmen der Forschungsarbeit verfolgt wurden, waren zum überwiegenden Teil das Wirkungsprinzip Allochthoner Kairomone sowie Abwehrverfahren bei denen Nichts-Wirtsbaum-Volatile zum Einsatz kommen. Als biologischer Detektor von zu identifizierenden Semiochemikalien aus Laubwaldhabitaten wurde der Ameisenbuntkäfer Thanasimus formicarius verwendet. Von T. formicarius ist eine stark generalistische Lebensweise bekannt, die zur Annahme verleitet, dass dieser auch als Prädator an diversen Laubholz besiedelnden Borkenkäferarten auftritt. Entsprechend wurden als Beuteobjekte in Laubwaldhabitaten die Arten Trypodendron domesticum, Trypodendron signatum, Leperisinus varius und Scolytus intricatus vermutet und schwerpunktartig untersucht. Mittels GC-MS/EAD-Analysen konnte nachgewiesen werden, dass T. formicarius Substanzen aus den Habitaten in Wäldern von Rot-Buche, Gemeiner Esche und Eiche wahrnehmen kann. Für einen Teil der von T. formicarius wahrgenommenen Substanzen wurden Dosis-Antwort-Kurven aufgenommen, um Erkenntnisse über die Wahrnehmungsschwelle bei T. formicarius zu erhalten und eine mögliche Bedeutungen der Substanzen in der olfaktorischen Orientierung im Laubwaldhabitat abzuleiten. Die Ergebnisse verdeutlichten, dass T. formicarius neben käferbürtigen Substanzen auch eine Vielzahl von pflanzenbürtigen Volatilen wahrnehmen kann. Dabei wurden für einige dieser Substanzen sehr geringe Wahrnehmungsschwellen festgestellt, was eine besondere Bedeutung der Substanzen in der olfaktorischen Orientierung von T. formicarius vermuten lässt. Substanzen, von welchen eine signifikante Wahrnehmung von T. formicarius erfasst werden konnte, wurden in Olfaktometerexperimenten auf verhaltensmodifizierende Wirkungen beim Ameisenbuntkäfer untersucht. Die in Laborexperimenten auf Wahrnehmung von T. formicarius getesteten Substanzen wurden letztlich in Fallenfangexperimente und Fangholzexperimente eingebunden. Ein Anflug von T. formicarius auf die in den Laborexperimenten erprobten Substanzen, konnte in Fallenfangexperimenten im Freiland, bei der Verwendung der zu erprobenden Substanzen als Einzelsubstanzen, kaum beobachtet werden. Auch die Kombination der Einzelsubstanzen zu Mixturen erzeugte keine nennenswerten Attraktivitäten auf T. formicarius und andere Prädatoren im Freiland. Dennoch schienen die Substanzen aufgrund ihrer teilweise repellenten Wirkung auf bast- und holzbesiedelnde Insekten geeignet, um zumindest in naturnahen Managementverfahren eingesetzt zu werden. Den Ergebnissen der Fallenfang- und Fangholzexperimente entsprechend können die aus dem Nadelwaldhabitat stammenden Pheromondispenser Sexowit® und Chalcogran als Allochthone Kairomone im Laubwaldhabitat empfohlen werden. Darüber hinaus scheint eine Applikation von exo-Brevicomin und endo-Brevicomin als Allochthone Kairomone im Nadelwaldhabitat denkbar, muss jedoch noch am Fangholz geprüft werden. Aus den Fallenfangexperimenten konnten zudem Substanzen abgeleitet werden, welche sich im Monitoring von bast- und holzbesiedelnden Insekten aus Laub- und Nadelwaldhabitaten eignen. / Nature-based methods in the regulation of bark and wood boring insects are based upon the use of olfactory responses of these insects and also partly of their antagonists to semiochemicals that originate from bark and wood boring insects or their host plants. Methods used during this research were the Allochthonous Kairomones principle and defense methods with non-host volatiles. Thanasimus formicarius was used as biological detector for identifying semiochemicals from deciduous forest habitats. T. formicarius is known to be a highly generalist predator, which led to the assumption that T. formicarius may occur as predator of various bark and wood boring insects living on deciduous tree species. Accordingly, Trypodendron domesticum, Trypodendron signatum, Leperisinus varius and Scolytus intricatus were assumed to be prey species in deciduous forest habitats and hence focused on in this study. A GC-MS/EAD analysis demonstrated that T. formicarius is able to perceive substances from the habitats of European beech, common ash and oak. For some of the perceived substances dose-response-curves were recorded to obtain knowledge about the perception threshold of T. formicarius and to derive the potential importance of the substances in the olfactory orientation in deciduous forest habitats. The results show that T. formicarius is able to recognize a variety of plant-derived volatiles as well as substances from bark and wood boring insects. For some of these substances very low perception thresholds were determined, suggesting a particular importance of these substances in the olfactory orientation of T. formicarius. Substances that were found to be significantly perceived by T. formicarius were further examined in olfactometer experiments in order to test for behavior-modifying effects. Substances that were tested for perception by T. formicarius in the laboratory experiments were finally included in trapping experiments and trap log experiments. When used as single compounds, low numbers of T. formicarius were attracted to substances used in trapping experiments. Also the combination of single substances to mixtures produced no significant attractions of T. formicarius and other predators in trapping experiments. However, some of the substances seemed to be appropriate for using in nature-based management methods because of repellent effects to bark and wood boring insects. According to the results of trapping and trap log experiments, pheromone dispensers such as Sexowit® and chalcogran from coniferous forest habitats can be recommended as Allochthonous Kairomones in deciduous forest habitats. In addition, an application of exo- and endo-brevicomin as Allochthonous Kairomones in coniferous forest habitats seems possible, but still has to be tested with trap log experiments. In addition within these experiments substances were detected that can be used in the monitoring of bark and wood boring insects in coniferous and deciduous forest habitats.
33

化学・同位体組成及び光学特性による溶存有機物のキャラクタリゼーション

吉岡, 崇仁 03 1900 (has links)
科学研究費補助金 研究種目:基盤研究(C)(2) 課題番号:10640474 研究代表者:吉岡 崇仁 研究期間:1998-1999年度

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