Detalhes bibliográficos
| Ano de defesa: |
2014 |
| Autor(a) principal: |
Costa, Renan Nunes
 |
| Orientador(a): |
Nomura, Fausto
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| Banca de defesa: |
Não Informado pela instituição |
| Tipo de documento: |
Dissertação
|
| Tipo de acesso: |
Acesso aberto |
| Idioma: |
por |
| Instituição de defesa: |
Universidade Federal de Goiás
|
| Programa de Pós-Graduação: |
Programa de Pós-graduação em Ecologia e Evolução (ICB)
|
| Departamento: |
Instituto de Ciências Biológicas - ICB (RG)
|
| País: |
Brasil
|
| Palavras-chave em Português: |
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| Palavras-chave em Inglês: |
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| Área do conhecimento CNPq: |
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| Link de acesso: |
http://repositorio.bc.ufg.br/tede/handle/tede/3472
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Resumo: |
There is a consensus among researchers in the world that the declining number of amphibian species and the increasing frequency of abnormalities in individual attributes of anurans are associated with habitat reduction and environmental contamination. With advance of agriculture crops, also increased the use of agrochemicals defensives, and the fragility of Brazilian laws for aquatic environmental protection burst the level of environmental stress significantly. Organisms can show biological responses related to these environmental modifications, that can be used to assess the environmental impact of agricultural practices. This biological response can be particularly useful, especially when we are able to correlate the biological response in morphological and/or physiological attributes with environmental impacts. The fluctuating asymmetry (FA) is a tool based on observation of deviations in the homeostasis of bilateral traits throughout the organism development and can be used for biomonitoring protocols. The FA can clarify which type of stressor is acting on a population. In this context, the present study assesses how the FA in anurans larvae can elucidate the impact of stressful factors. In the first chapter, our objective was to test experimentally if exposure to glyphosate dosages (Roundup® Original herbicide) affect the survival and increase the development deviations in the Physalaemus cuvieri larvae. In acute exposure, the survival rate was decreased at higher levels of contamination and the LC50 observed was considered to moderately toxic. In the chronic exposure, resulting from contamination, individuals showed higher levels of FA in relation to control larvae. In the second chapter, based on field sampling, our objective was to assess if reduction of physical habitat integrity, expressed by land use and reduction of marginal vegetation near to water bodies, reflected in higher levels in fluctuating asymmetry in P. cuvieri and Scinax fuscomarginatus larvae. In this case, with increased level of impact on the surrounding matrix, the larvae of both species showed increased of FA levels. In S. fuscomarginatus, the FA levels were also higher in environments with lower percentage of edge vegetation. In summary, it’s observed that increasing environmental stress, either through contamination by glyphosate or increased anthropogenic modification of the margins of water bodies, reflects in the higher development deviations on the frog’s larvae. The affected structures can be associated with sensory capabilities of the species, in which the increased frequency of these deviations can reduce individual fitness and influence the population homeostasis over time, directly contributing to species declines. |
