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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.
71

Rhythms and Evolution: Effects of Timing on Survival

Pace, Bruno 11 March 2016 (has links)
The evolution of metabolism regulation is an intertwined process, where different strategies are constantly being developed towards a cognitive ability to perceive and respond to an environment. Organisms depend on an orchestration of a complex set of chemical reactions: maintaining homeostasis with a changing environment, while simultaneously sending material and energetic resources to where they are needed. The success of an organism requires efficient metabolic regulation, highlighting the connection between evolution, population dynamics and the underlying biochemistry. In this work, I represent organisms as coupled information-processing networks, that is, gene-regulatory networks receiving signals from the environment and acting on chemical reactions, eventually affecting material flows. I discuss the mechanisms through which metabolism control is improved during evolution and how the nonlinearities of competition influence this solution-searching process. The propagation of the populations through the resulting landscapes generally point to the role of the rhythm of cell division as an essential phenotypic feature driving evolution. Subsequently, as it naturally follows, different representations of organisms as oscillators are constructed to indicate more precisely how the interplay between competition, maturation timing and cell-division synchronisation affects the expected evolutionary outcomes, not always leading to the \"survival of the fastest\".
72

Jak se liší druhové bohatství a početnost ptáků mezi vojenskými výcvikovými prostory a okolní krajinou? Případová studie z vojenského újezdu Hradiště / How do bird species richness and abundance differ between military training areas and surrounding landscape? A case study from the Hradiště military area

Bušek, Ondřej January 2015 (has links)
Since the beginning of the 20th century human land use changed drastically in Central Europe. These changes included: homogenization of the landscape mosaic, intensification of agriculture, urbanization and land abandonment. In turn, these changes affected bird species and perhaps most significantly manifested in population decline of open habitat birds. Therefore, it is important to investigate sites, which were not affected by the changes mentioned above, such as military training areas (MTAs) - places dedicated to training of armed forces. Previous studies have shown that MTAs seem to host remarkably high bird diversity and abundant populations of bird species of conservation concern. This may be caused by two major factors. First, closure of MTAs to all human activies besides military training spared them of the landscape changes mentioned above. Second, the military training itself produces a very heterogeneous habitat mosaic that allows coexistence of many species with different ecological requirements. To my knowledge, no study compared bird assemblages between MTAs and surrounding landscape directly. At the same time, such data are crucial to assess the value of MTAs for bird conservation reliably and, as a consequence, they enable to think more deeply about mechanism generating this value....
73

Small mammal and bird abundance in relation to post-fire habitat succession in mountain big sagebrush (Artemisia tridentata ssp. vaseyana) communities

Holmes, Aaron L. 28 December 2010 (has links)
Fire is an important disturbance mechanism in big sagebrush (Artemisia tridentata) communities, yet little is known about wildlife population dynamics during post-fire habitat succession. I estimated the abundance of small mammals and birds in relation to fire history in mountain big sagebrush (A.t. spp. vaseyana) communities on the Sheldon National Wildlife Refuge in the northwestern Great Basin, USA. I employed a chronosequence approach that took advantage of multiple wildfires that had occurred in similar plant communities between 7 to 20 years prior to sampling. Belding’s ground squirrel (Spermophilus beldingii) were approximately 10 times as abundant in burned areas relative to adjacent unburned habitat regardless of the number of years since a burn occurred. Deer mouse (Peromyscus maniculatus) was more abundant on more recently burned sites, but not at sites closer to full vegetation recovery. Great basin pocket mouse (Perognathus parvus), sagebrush vole (Lemmiscus curtatus), and least chipmunk (Tamius minimus) abundance did not vary as a function of fire history, but some variance was explained by habitat features such as rocky areas and the canopy characteristics of sagebrush. Bird diversity was higher in unburned habitats irrespective of the number of years of recovery out to 20 years. Nine of the 12 most widely occurring species of birds in the study have population densities influenced by fire or post-fire habitat succession to at least 13 to 20 years following a burn. Sage Sparrow (Amphispiza belli), Black-throated Sparrow (Amphispiza bilineata), and Spotted Towhee (Pipilo maculatus) occurred at relatively low densities and were nearly restricted to unburned habitats. Green-tailed Towhee (Pipilo Chlorurus), Gray Flycatcher (Empidonax wrightii), American Robin (Turdus migratorius), and Brown-headed Cowbird (Molothus ater) occurred at lower densities in burned areas than adjacent unburned areas although the relationship was not strong for the latter two species. The magnitude of the difference in density between burned and unburned sites within a landscape diminished with the number of years of vegetation recovery for Green-tailed Towhee. Brewer’s Sparrow (Spizella brewerii) occurred at lower densities relative to adjacent habitat in the most recent burn, but occurred at higher densities after 20 years of habitat succession, suggesting a positive response with a multiple decade lag period. Horned Lark (Eremophila alpestris) and Vesper Sparrow (Pooecetes gramineus) respond positively to fire, but densities were similar to unburned areas after 20 years of habitat succession. An ordination analysis captured 86% of the variation in 12 bird species with 3 orthogonal axes. My research demonstrates that strong community structure exists for birds associated with mountain big sagebrush habitats, and that fire influences community structure for multiple decades. / Graduation date: 2011 / Access restricted to the OSU Community at author's request from Dec. 22, 2010 - Dec. 22, 2011.
74

Influência do desenvolvimento florestal sobre a comunidade edáfico-epígea de Arthropoda e a mirmecofauna: bases para a bioindicação do processo sucessional na restauração ecológica / The influence of forest development on edaphic and epigeic Arthropod communities and ant fauna: bases for bioindicantion of successional process in ecological restoration

Meloni, Fernando 26 October 2012 (has links)
A restauração ecológica visa o estabelecimento de ecossistemas semelhantes aos que originalmente ocupavam uma determinada área que foi degradada. Todavia, os resultados dos esforços envolvidos na restauração e no retorno dos processos ecológicos naturais são difíceis de serem medidos, pois faltam métodos apropriados. Os bioindicadores são ferramentas baratas e confiáveis para o diagnóstico das características ambientais e ecológicas, cujo princípio consiste em medidas simples de grupos biológicos especialmente sensíveis às mudanças no meio. Os Arthropoda que ocorrem no solo e na serapilheira, em especial as formigas, mediam processos ecológicos importantes e apresentam características que os tornam bioindicadores potenciais, mas seu uso ainda necessita de conhecimentos específicos. Assim, o presente estudo teve como objetivo testar o potencial indicador da comunidade de Arthropoda edáfico-epígea na restauração ecológica, com maior enfoque sobre as formigas. Foram avaliadas as comunidades de um gradiente sucessional formado por doze reflorestamentos com diferentes idades e três remanescentes florestais, localizados nas bacias dos rios Pardo e Mogi-Guaçu. O objetivo foi identificar quais os parâmetros que melhor refletem a resposta dessas comunidades ao desenvolvimento florestal. Os resultados indicaram que tanto a mirmecofauna como o restante da comunidade são influenciadas pelos estádios de desenvolvimento florestal. As comunidades variaram em composição e estrutura. A evolução das comunidades mostrou-se direcional, formando um padrão convergente de acordo com o avanço da sucessão. Os resultados indicaram forte efeito da sazonalidade e das técnicas de coleta na interpretação dos resultados. A comunidade edáfico-epígea encontrada no período seco mostrou-se especialmente sensível ao desenvolvimento florestal, enquanto a resposta da mirmecofauna foi mais evidente durante o período chuvoso. Os resultados indicaram também que as comunidades de diferentes regiões, Mogi-Guaçu e Ribeirão Preto, responderam ao processo sucessional, embora tenham apresentado diferenças na composição e no padrão de resposta. As análises com formigas classificadas em grupos funcionais indicaram que a resposta da mirmecofauna ao desenvolvimento florestal ocorre também no nível funcional. As mudanças nos padrões da comunidade e seus módulos estão relacionadas às mudanças nos filtros ambientais e à disponibilidade de nichos. Em conclusão, (1) a riqueza de espécies da fauna edáfico-epígea encontrada na serapilheira do período seco foi um bom preditor geral do desenvolvimento florestal; (2) a riqueza de grupos raros proporcionou o melhor modelo de prognóstico do estádio sucessional, indicando ainda que os reflorestamentos tendem a atingir patamares semelhantes aos encontrados nos remanescentes florestais por volta dos 27 anos após o plantio; (3) na comunidade edáfico-epígea, o avanço no desenvolvimento florestal levou à convergência entre padrões de composição, (4) enquanto na mirmecofauna a convergência ocorreu para os padrões de estrutura, sendo que em ambos os casos (3 e 4), quanto mais avançado o estádio sucessional, mais parecidos entre si são os padrões de locais diferentes; (5) a Equabilidade J das formigas amostradas por iscas decresceu ao longo do desenvolvimento florestal, sendo considerado também um indicador do processo sucessional (6) as classificações funcionais das formigas também permitiram boa predição dos estádios sucessionais, com destaque para formigas capturadas com iscas quando classificadas pelo sistema proposto por Andersen (1995), devido a boa relação custo/benefício. Portanto, foi confirmado o potencial bioindicador da mirmecofauna de comunidade edáfico-epígea geral, que podem ser utilizados como ferramentas de diagnóstico e monitoramento do processo sucessional. O uso mais apropriado deve ser feito por métodos comparativos, através de parâmetros provenientes de ecossistemas referência, ou por medidas repetidas ao longo do tempo, pela observação do deslocamento dos padrões da comunidade e interpretação da proporção dos grupos. / Ecological restoration objective is to promote the return of chemical, physical and biological natural properties as those similar to the native features as possible. However, the restoration projects cannot be well evaluated due to the fact that there are no appropriated tools to do that. Plantations using native species are a prominent technique used in São Paulo state, promoting the fast rising of a plant community, but it is very expensive and hard to measure if ecological processes are returning. Bioindicators are cheap tools to evaluate environmental conditions and ecological processes because they respond to all ecosystem characteristics acting together and the responses of a single group make possible to infer properties of the total biodiversity or the full ecosystem health. Epigeic and hipogeic Arthropoda, especially ants, are potential bioindicators, due to their high abundance, ubiquitousness and their straight relationship to some important ecological processes, even to other community components, but they have not been used because it lacks information about the local scale responses to successional process and which standards can be used as parameters. Hence, we have tried to understand the main standards and responses from soil and litter community, as well as the mirmecofauna responses, under a successional gradient constituted by twelve planted forests in different ages and three forest remainders (semi-deciduous forest), all located at the hydrographic basins, Pardo and Mogi-Guaçu, searching for trustful bioindicators of forest development. General fauna was sampled from litter and soil and ants were additionally sampled by attractive baits, using glucose and sardine. Results have showed that forest development makes influence on structure and composition of general communities and ant communities found in restoration sites, so that over time, these community parameters progressively have become more similar to those found in forest remainders, consisting in a directional shifting. Epigeic and hipogeic general fauna showed to be more sensitive to forest development through dry season, while ants presented critical responses in wet season. Communities from different regions were influenced by successional process but they have presented differences among fauna compositions. The analyses using ants classified in functional groups indicated that forest development makes influence also on fauna functional pattern. Groups occupying specialized niches tend to increase their relative amount throughout forest development. The shifting of ant community functionality may be related to changes in environmental filters plus the increase of niche availability through forest development. As conclusions, under experiment features (1) species richness of litter fauna of dry season is a good predictor of forest development; (2) the richness of rare taxa allowed the best prognosis about sucessional stage, also indicating that fauna found in forest plantations reaches similar fauna standards of forest remainders close to 27 years after the deployment; (3) over time, the composition of general edaphic-epigeic community found in restoration sites becomes more similar to composition of communities found in forest remainders, (4) while for ant communities, the structure standards found in restoration sites progressively become more similar of respective parameter found in forest remainders. (5) the Equitability J of ants communities sampled using baits decreases over forest development and it may be considered a bioindicator of sucessional process; (6) ant functional groups also provided good prediction of sucessional stages, highlighting ant sampling using baits and ant functional classification according to Andersen (1995), due to best benefit-cost ratio. For appropriated application of all bioindicators, the use of comparative techniques may be considered, including ecosystem references, and rather than it uses fixed values of fauna parameters (as fixed goals to be achieved), it is better to consider which parameters of the community are changing over time and if their tendencies are in accordance to the expected.
75

Influência do desenvolvimento florestal sobre a comunidade edáfico-epígea de Arthropoda e a mirmecofauna: bases para a bioindicação do processo sucessional na restauração ecológica / The influence of forest development on edaphic and epigeic Arthropod communities and ant fauna: bases for bioindicantion of successional process in ecological restoration

Fernando Meloni 26 October 2012 (has links)
A restauração ecológica visa o estabelecimento de ecossistemas semelhantes aos que originalmente ocupavam uma determinada área que foi degradada. Todavia, os resultados dos esforços envolvidos na restauração e no retorno dos processos ecológicos naturais são difíceis de serem medidos, pois faltam métodos apropriados. Os bioindicadores são ferramentas baratas e confiáveis para o diagnóstico das características ambientais e ecológicas, cujo princípio consiste em medidas simples de grupos biológicos especialmente sensíveis às mudanças no meio. Os Arthropoda que ocorrem no solo e na serapilheira, em especial as formigas, mediam processos ecológicos importantes e apresentam características que os tornam bioindicadores potenciais, mas seu uso ainda necessita de conhecimentos específicos. Assim, o presente estudo teve como objetivo testar o potencial indicador da comunidade de Arthropoda edáfico-epígea na restauração ecológica, com maior enfoque sobre as formigas. Foram avaliadas as comunidades de um gradiente sucessional formado por doze reflorestamentos com diferentes idades e três remanescentes florestais, localizados nas bacias dos rios Pardo e Mogi-Guaçu. O objetivo foi identificar quais os parâmetros que melhor refletem a resposta dessas comunidades ao desenvolvimento florestal. Os resultados indicaram que tanto a mirmecofauna como o restante da comunidade são influenciadas pelos estádios de desenvolvimento florestal. As comunidades variaram em composição e estrutura. A evolução das comunidades mostrou-se direcional, formando um padrão convergente de acordo com o avanço da sucessão. Os resultados indicaram forte efeito da sazonalidade e das técnicas de coleta na interpretação dos resultados. A comunidade edáfico-epígea encontrada no período seco mostrou-se especialmente sensível ao desenvolvimento florestal, enquanto a resposta da mirmecofauna foi mais evidente durante o período chuvoso. Os resultados indicaram também que as comunidades de diferentes regiões, Mogi-Guaçu e Ribeirão Preto, responderam ao processo sucessional, embora tenham apresentado diferenças na composição e no padrão de resposta. As análises com formigas classificadas em grupos funcionais indicaram que a resposta da mirmecofauna ao desenvolvimento florestal ocorre também no nível funcional. As mudanças nos padrões da comunidade e seus módulos estão relacionadas às mudanças nos filtros ambientais e à disponibilidade de nichos. Em conclusão, (1) a riqueza de espécies da fauna edáfico-epígea encontrada na serapilheira do período seco foi um bom preditor geral do desenvolvimento florestal; (2) a riqueza de grupos raros proporcionou o melhor modelo de prognóstico do estádio sucessional, indicando ainda que os reflorestamentos tendem a atingir patamares semelhantes aos encontrados nos remanescentes florestais por volta dos 27 anos após o plantio; (3) na comunidade edáfico-epígea, o avanço no desenvolvimento florestal levou à convergência entre padrões de composição, (4) enquanto na mirmecofauna a convergência ocorreu para os padrões de estrutura, sendo que em ambos os casos (3 e 4), quanto mais avançado o estádio sucessional, mais parecidos entre si são os padrões de locais diferentes; (5) a Equabilidade J das formigas amostradas por iscas decresceu ao longo do desenvolvimento florestal, sendo considerado também um indicador do processo sucessional (6) as classificações funcionais das formigas também permitiram boa predição dos estádios sucessionais, com destaque para formigas capturadas com iscas quando classificadas pelo sistema proposto por Andersen (1995), devido a boa relação custo/benefício. Portanto, foi confirmado o potencial bioindicador da mirmecofauna de comunidade edáfico-epígea geral, que podem ser utilizados como ferramentas de diagnóstico e monitoramento do processo sucessional. O uso mais apropriado deve ser feito por métodos comparativos, através de parâmetros provenientes de ecossistemas referência, ou por medidas repetidas ao longo do tempo, pela observação do deslocamento dos padrões da comunidade e interpretação da proporção dos grupos. / Ecological restoration objective is to promote the return of chemical, physical and biological natural properties as those similar to the native features as possible. However, the restoration projects cannot be well evaluated due to the fact that there are no appropriated tools to do that. Plantations using native species are a prominent technique used in São Paulo state, promoting the fast rising of a plant community, but it is very expensive and hard to measure if ecological processes are returning. Bioindicators are cheap tools to evaluate environmental conditions and ecological processes because they respond to all ecosystem characteristics acting together and the responses of a single group make possible to infer properties of the total biodiversity or the full ecosystem health. Epigeic and hipogeic Arthropoda, especially ants, are potential bioindicators, due to their high abundance, ubiquitousness and their straight relationship to some important ecological processes, even to other community components, but they have not been used because it lacks information about the local scale responses to successional process and which standards can be used as parameters. Hence, we have tried to understand the main standards and responses from soil and litter community, as well as the mirmecofauna responses, under a successional gradient constituted by twelve planted forests in different ages and three forest remainders (semi-deciduous forest), all located at the hydrographic basins, Pardo and Mogi-Guaçu, searching for trustful bioindicators of forest development. General fauna was sampled from litter and soil and ants were additionally sampled by attractive baits, using glucose and sardine. Results have showed that forest development makes influence on structure and composition of general communities and ant communities found in restoration sites, so that over time, these community parameters progressively have become more similar to those found in forest remainders, consisting in a directional shifting. Epigeic and hipogeic general fauna showed to be more sensitive to forest development through dry season, while ants presented critical responses in wet season. Communities from different regions were influenced by successional process but they have presented differences among fauna compositions. The analyses using ants classified in functional groups indicated that forest development makes influence also on fauna functional pattern. Groups occupying specialized niches tend to increase their relative amount throughout forest development. The shifting of ant community functionality may be related to changes in environmental filters plus the increase of niche availability through forest development. As conclusions, under experiment features (1) species richness of litter fauna of dry season is a good predictor of forest development; (2) the richness of rare taxa allowed the best prognosis about sucessional stage, also indicating that fauna found in forest plantations reaches similar fauna standards of forest remainders close to 27 years after the deployment; (3) over time, the composition of general edaphic-epigeic community found in restoration sites becomes more similar to composition of communities found in forest remainders, (4) while for ant communities, the structure standards found in restoration sites progressively become more similar of respective parameter found in forest remainders. (5) the Equitability J of ants communities sampled using baits decreases over forest development and it may be considered a bioindicator of sucessional process; (6) ant functional groups also provided good prediction of sucessional stages, highlighting ant sampling using baits and ant functional classification according to Andersen (1995), due to best benefit-cost ratio. For appropriated application of all bioindicators, the use of comparative techniques may be considered, including ecosystem references, and rather than it uses fixed values of fauna parameters (as fixed goals to be achieved), it is better to consider which parameters of the community are changing over time and if their tendencies are in accordance to the expected.

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