<p>Fish is considered to be a keystone predator in freshwater habitats. Several studies have shown that the species composition of odonates (Odonata) is different between habitats with and without fish, and that odonates depending on the behaviour and physical characteristics of the individual species react differently to the presence of fish, some positively, some negatively and others not at all. This study aims to study the effect of fish as predators on the odonate community, and especially the little studied effect of the presence and composition of different ecological groups of fish in lakes. 92 Swedish lakes were surveyed for abundances and species compositions of odonates. The composition of fish species in the lakes was determined from official sources and divided into seven ecological groups. While several of the tests for potential interactions between fish and odonates resulted in no significance, the discrimination analyses of the different ecological groups of fish tested against odonate species composition did reveal high classification coefficients, indicating that different ecological groups have different odonate communities. Number of species of fish did also have a fairly high classification coefficient in a discriminant analysis. A combined plot show that two categories of lakes are separating from the others in odonate composition. Both these categories lacked some littoral groups of fish, indicating that littoral fish species may have a strong influence on the odonate community. The study also concluded that both lake size and latitude are potential confounding variables.</p>

Fish is considered to be a keystone predator in freshwater habitats. Several studies have shown that the species composition of odonates (Odonata) is different between habitats with and without fish, and that odonates depending on the behaviour and physical characteristics of the individual species react differently to the presence of fish, some positively, some negatively and others not at all. This study aims to study the effect of fish as predators on the odonate community, and especially the little studied effect of the presence and composition of different ecological groups of fish in lakes. 92 Swedish lakes were surveyed for abundances and species compositions of odonates. The composition of fish species in the lakes was determined from official sources and divided into seven ecological groups. While several of the tests for potential interactions between fish and odonates resulted in no significance, the discrimination analyses of the different ecological groups of fish tested against odonate species composition did reveal high classification coefficients, indicating that different ecological groups have different odonate communities. Number of species of fish did also have a fairly high classification coefficient in a discriminant analysis. A combined plot show that two categories of lakes are separating from the others in odonate composition. Both these categories lacked some littoral groups of fish, indicating that littoral fish species may have a strong influence on the odonate community. The study also concluded that both lake size and latitude are potential confounding variables.

Made available in DSpace on 2014-06-11T19:35:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-12-17Bitstream added on 2014-06-13T20:07:14Z : No. of bitstreams: 1 fulan_ja_dr_botib.pdf: 531904 bytes, checksum: 89afc77c13041e5eb47cfb408bbe3a1e (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo deste trabalho foi comparar simultaneamente, no período de março de 2006 a fevereiro de 2007, a distribuição de larvas de Odonata juntas à macrófita Salvinia auriculata em quatro ambientes com características limnológicas distintas: Rio Paranapanema, Rio Guareí, Lagoa dos Cavalos e Lagoa do Coqueiral. Também fez parte dos objetivos verificar as características físicas e químicas das águas dos quatro ambientes e investigar seus efeitos no padrão de distribuição espacial das larvas de Odonata. As seguintes variáveis foram medidas na superfície da água: oxigênio dissolvido, pH, condutividade, material em suspensão e temperatura. A profundidade local e a temperatura do ar foram também medidas. Dados de precipitações mensais foram obtidos. Foi também determinada a biomassa total da macrófita. Para interpretação dos resultados, foram utilizadas uma análise de componentes principais (ACP), uma análise de correspondência canônica (ACC), uma análise de variância (ANOVA) e correlação de Spearman. A ACC mostrou que os fatores que mais atuaram sobre a densidade dos macroinvertebrados foram profundidade no Rio Paranapanema, oxigênio e profundidade no Rio Guareí e na Lagoa do Coqueiral e temperatura de superfície da água na Lagoa dos Cavalos. A diversidade de larvas de Odonata foi sempre maior no Rio Guareí, exceto em abril, agosto e dezembro de 2006. A Lagoa do Coqueiral foi o ambiente com as maiores densidades e riquezas de larvas de Odonata. Concluímos que apesar dos quatro ambientes apresentarem características físicas e químicas de suas águas distintas, a composição de gêneros de Odonata foi semelhante nesses ecossistemas. Entretanto, a diversidade de Odonata foi maior no Rio Guareí, apesar de ser um ambiente com uma forte ação antrópica. Não evidenciamos composição diferente de larvas de Odonata nos ambientes lóticos... / The aim of this work was to compare at the same time, in period from March 2006 to February 2007 the larvae distribution Odonate in four environments with limnological distinct characteristics: Paranapanema and Guareí Rivers, Cavalos and Coqueiral Lakes. We compare also the water physical and chemical characteristics of the four aquatic ecosystems and we investigated its effects on spatial distribution pattern of the Odonate larvae. The measured environmental variables were: dissolved oxygen, pH, conductivity, suspended matter and surface water temperature. The depth in sampled sites and air temperature were also measured. Monthly precipitation data were obtained. The dry weight of the macrophyte was also determined. To interpret the results, the following statistical analyses were used: the Principal Components Analysis (PCA), the Correspondence Canonical Analysis (CCA), the Variance Analysis (ANOVA) and the Spearman Correlation. CCA showed that the environmental factors that more affected the macroinvertebrates density were the depth in Paranapanema River, dissolved oxygen and depth in Guareí River and Coqueiral Lake and surface water temperature in Cavalos Lake. The larvae diversity Odonate was higher in Guareí River, except in April, August and December 2006. Coqueiral Lake was the site with the higher density and richness genera of Odonate larvae. We concluded that, despite of the four environments exhibited distinct water physics and chemical characteristics, the Odonata composition was similar in these ecosystems. However, the Odonate diversity was higher in Guareí River, despite of high human disturbance. We did not recorded a distinct composition of Odonate larvae in studied lotic and lentic ecosystems, despite of some taxa as Calopterygidae had occurred exclusively in a lotic ecosystem

Orientador: Raoul Henry / Banca: Virginia Sanches Uieda / Banca: Gilza Maria de Souza Franco / Banca: Afonso Pelli / Banca: Alcimar do Lago Carvalho / Resumo: O objetivo deste trabalho foi comparar simultaneamente, no período de março de 2006 a fevereiro de 2007, a distribuição de larvas de Odonata juntas à macrófita Salvinia auriculata em quatro ambientes com características limnológicas distintas: Rio Paranapanema, Rio Guareí, Lagoa dos Cavalos e Lagoa do Coqueiral. Também fez parte dos objetivos verificar as características físicas e químicas das águas dos quatro ambientes e investigar seus efeitos no padrão de distribuição espacial das larvas de Odonata. As seguintes variáveis foram medidas na superfície da água: oxigênio dissolvido, pH, condutividade, material em suspensão e temperatura. A profundidade local e a temperatura do ar foram também medidas. Dados de precipitações mensais foram obtidos. Foi também determinada a biomassa total da macrófita. Para interpretação dos resultados, foram utilizadas uma análise de componentes principais (ACP), uma análise de correspondência canônica (ACC), uma análise de variância (ANOVA) e correlação de Spearman. A ACC mostrou que os fatores que mais atuaram sobre a densidade dos macroinvertebrados foram profundidade no Rio Paranapanema, oxigênio e profundidade no Rio Guareí e na Lagoa do Coqueiral e temperatura de superfície da água na Lagoa dos Cavalos. A diversidade de larvas de Odonata foi sempre maior no Rio Guareí, exceto em abril, agosto e dezembro de 2006. A Lagoa do Coqueiral foi o ambiente com as maiores densidades e riquezas de larvas de Odonata. Concluímos que apesar dos quatro ambientes apresentarem características físicas e químicas de suas águas distintas, a composição de gêneros de Odonata foi semelhante nesses ecossistemas. Entretanto, a diversidade de Odonata foi maior no Rio Guareí, apesar de ser um ambiente com uma forte ação antrópica. Não evidenciamos composição diferente de larvas de Odonata nos ambientes lóticos... (Resumo completo clicar acesso eletrônico abaixo) / Abstract: The aim of this work was to compare at the same time, in period from March 2006 to February 2007 the larvae distribution Odonate in four environments with limnological distinct characteristics: Paranapanema and Guareí Rivers, Cavalos and Coqueiral Lakes. We compare also the water physical and chemical characteristics of the four aquatic ecosystems and we investigated its effects on spatial distribution pattern of the Odonate larvae. The measured environmental variables were: dissolved oxygen, pH, conductivity, suspended matter and surface water temperature. The depth in sampled sites and air temperature were also measured. Monthly precipitation data were obtained. The dry weight of the macrophyte was also determined. To interpret the results, the following statistical analyses were used: the Principal Components Analysis (PCA), the Correspondence Canonical Analysis (CCA), the Variance Analysis (ANOVA) and the Spearman Correlation. CCA showed that the environmental factors that more affected the macroinvertebrates density were the depth in Paranapanema River, dissolved oxygen and depth in Guareí River and Coqueiral Lake and surface water temperature in Cavalos Lake. The larvae diversity Odonate was higher in Guareí River, except in April, August and December 2006. Coqueiral Lake was the site with the higher density and richness genera of Odonate larvae. We concluded that, despite of the four environments exhibited distinct water physics and chemical characteristics, the Odonata composition was similar in these ecosystems. However, the Odonate diversity was higher in Guareí River, despite of high human disturbance. We did not recorded a distinct composition of Odonate larvae in studied lotic and lentic ecosystems, despite of some taxa as Calopterygidae had occurred exclusively in a lotic ecosystem / Doutor

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