The influence of regional processes, such as dispersal, on ecological communities has been the focal point of considerable ecological research. Evidence has shown that dispersal can impact community composition through interactions with predation, the introduction of keystone species, and maintenance of species lost due to competitive exclusion. Ecological communities can be characterized by several metrics including species richness, diversity, evenness, abundance and species co-occurrence patterns. Negative species co-occurrence patterns have historically been attributed to competitive interactions between species causing pairs of species to never co-occur. However, little attention has been paid to the contribution of dispersal on species co-occurrence patterns. I have experimentally investigated the influence of dispersal on species co-occurrence patterns in addition to local species richness, total species abundance, evenness, and Simpson’s diversity. Local species richness significantly increased with dispersal, with variation in total local richness being mainly attributed to differences in the rotifer community. Local diversity, total abundance, and evenness were not significantly influenced by changes in the level of dispersal. Species co-occurrence patterns were greatly affected by changes in dispersal, with negative species co-occurrence patterns peaking at intermediate levels of dispersal. The potential for dispersal to increase the number of rare species within a community suggested that the presence of rare species could be behind the changes in the co-occurrence patterns between dispersal treatments. The effect size of the co-occurrence tests increased with the removal of rare species in the intermediate dispersal treatment and decreased in the remaining dispersal treatments. Likely, through mass effects, the presence of rare species, and the establishment of keystone predators changes in the level of dispersal strongly influenced species co-occurrence patterns. I conclude that external processes, like dispersal, can influence species co-occurrence patterns and that caution should be taken when interpreting the mechanisms driving species co-occurrence patterns across landscapes. / Thesis (Master, Biology) -- Queen's University, 2011-09-28 15:00:40.972

GENERAL ABSTRACT The Laurentian Great Lake wetlands are highly productive and complex systems. The net loss of wetlands since European settlement has been dramatic. The remaining coastal wetlands continue to be threatened with obliteration or severe environmental degradation. Therefore, the overall objective of this study was to provide information on the ecology of the remaining coastal wetlands within the lower Great Lakes. This study describes a coastal wetland fish community along the north shore of Lake Erie within Long Point Marsh complex over a 24-h period and catch characteristics of three common fishing techniques. The fish community was sampled at two hour intervals over a 24-h period in June, and used three types of gear to determine possible sampling biases from the different collection techniques. A total of 497 fish encompassing 11 taxa were collected. A 2-h interval, four hours prior to sunset, netted the largest number of taxa (including 3 functional feeding groups: ornmvores, planktivores, and piscivores ), as well as highest abundance and biomass values. Seine netting demonstrated a biased towards sampling the smaller planktivores, while fyke nets were biased towards larger omnivorous fish, and boat electrofishing was biased towards the large piscivores. These results will assist scientists and lake managers to develop standardized fish sampling protocol in order to accurately assess differences in wetland fish communities. Seven coastal wetlands within Lake Erie and Ontario along both the Canadian and United States shorelines were studied to verify predicted relationships from the literature and determine the relative influences of various habitat features on zooplankton community structure. Water quality, aquatic macrophyte, zooplankton, and fish community information were collected from the wetlands between July 4th and August 2nd of 2001. The predicted relationships from the literature concerning water quality and macrophyte species richness were verified by the results of this work. Water quality and macrophyte species richness were the most accurate predictors of wetland zooplankton community structure. Identifying the wetland characteristics that play primary roles in structuring zooplankton communities will also assist lake managers to make informed decisions of how to most effectively improve zooplankton habitat, to foster larger-bodied zooplankton populations, making the habitat more suitable for larger populations of larval and juvenile fish. / Thesis / Master of Science (MS)

A bacia hidrográfica do Arroio Candiota está situada no sudoeste do Estado do Rio Grande do Sul, Brasil. Sofre intensa atividade antrópica, como mineração de carvão e calcário, pecuária, silvicultura e agricultura. Apresenta ainda em seu território a Usina Termelétrica Presidente Médici - UTPM - Candiota II. Este trabalho teve como objetivo analisar a variação temporal da comunidade zooplanctônica, representada por Rotifera, Cladocera e Copepoda, a partir das variáveis ambientais e atributos funcionais em alguns arroios impactados pelos diferentes usos da bacia hidrográfica do Arroio Candiota. Foram realizadas coletas trimestrais de água e zooplâncton com o intuito de caracterizar as estações climáticas do ano, durante o período de abril/2007 a outubro/2014. As coletas ocorreram em sete estações amostrais diferentes, totalizando 161 unidades amostrais. As variáveis físicas e químicas selecionadas para este trabalho foram pH, turbidez, ferro dissolvido, oxigênio dissolvido e temperatura. Para as análises estatísticas foram utilizados modelos lineares generalizados (GLM), cálculo da diversidade das espécies, que envolveu duas medidas baseadas em distâncias topológicas, a distinção taxonômica (Δ*) e a diversidade taxonômica (Δ), análise de espécies indicadoras (ISA) e análise de atributos indicadores (ITA). Foram identificados 152 táxons ao total das coletas. Rotifera foi predominante com 122 espécies, após Cladocera com 16 espécies e Copepoda com 14 espécies. Os resultados mostraram que o pH foi a única variável que apresentou resultado significativo com valores positivamente proporcionais para a abundância de espécies. Em relação à riqueza de espécies, as variáveis pH, ferro dissolvido e oxigênio dissolvido influenciaram positivamente ao longo do tempo. O cálculo da diversidade e distinção taxonômica demonstrou que das 161 unidades amostrais, 127 mostraram valores de diversidade conforme o esperado ao acaso na natureza. Quatro unidades amostrais apresentaram valores da diversidade acima do esperado e 31 exibiram valores abaixo do esperado ao acaso. A ISA identificou duas espécies indicadoras da estação amostral 1 e cinco espécies indicadoras da estação amostral 2. Foram encontradas cinco espécies indicadoras específicas do inverno, cinco do outono, quatro da primavera e nove espécies indicadoras no verão. A ITA demonstrou que espécies de tamanho C4 (≥ 1000 μm), tiveram maior ocorrência no inverno e primavera. O atributo funcional “coletores e raspadores” foi considerado indicador para as estações amostrais EA1 e EA3 por cinco espécies. Os resultados encontrados não demonstraram um gradiente contínuo de crescimento ou declínio da abundância e riqueza de espécies ao longo do tempo. Assim, a comunidade zooplanctônica parece ser mais fortemente influenciada pelas características naturais de Candiota, como relevo e rede de drenagem, com exceção dos riachos que recebem diretamente efluentes da mineração de carvão. / The Arroio Candiota watershed is located in the southwestern state of Rio Grande do Sul, Brazil. It suffers intense human activity, such as mining of coal and limestone, livestock, forestry and agriculture. It also presents in its territory the Thermoelectric Plant Presidente Medici - UTPM - Candiota II. This study aimed to analyze the temporal variation of zooplankton community, represented by Rotifers, Cladocera and Copepoda, from the environmental variables and functional attributes in some streams impacted by different uses of the Arroio Candiota watershed. Quarterly sampling of water and zooplankton were conducted in order to characterize the seasons of the year, during the period April/2007 to October/2014. The collections occurred in seven different sampling stations, totaling 161 sampling units. The physical and chemical variables selected for this study were pH, turbidity, dissolved iron, dissolved oxygen and temperature. For statistical analysis we used generalized linear models (GLM), calculating the diversity of species, which involved two measures based on topological distances, the taxonomic distinction (Δ*) and taxonomic diversity (Δ), indicator species analysis (ISA) and indicators atributes analysis (ITA). There were identified 152 taxa to the total collections. Rotifera was predominant with 122 species, 16 species of Cladocera and 14 species of Copepoda. The results showed that pH was the only variable that showed significant results with positive values proportional to the abundance of species. The variables pH, dissolved iron and dissolved oxygen positively influenced the richness of species over time. The calculation of diversity and taxonomic distinction showed that of the 161 sampling units, 127 showed diversity of values as expected at random in nature. Four sampling campaigns showed values of diversity than expected and 31 showed values lower than expected by chance. The ISA has identified two indicator species of the sampling station 1 and 5 indicator species of sampling station 2. We found five specific indicator winter species, five in autumn, four in spring and nine summer indicator species. The ITA has shown that species of C4 size (≥ 1000 μm), were more frequent in winter and spring. The functional attribute "collectors and scrapers" was considered indicator for the sampling stations 1 and 3 with five species. The results did not demonstrate a continuous gradient of growth or decline in abundance and species richness over time. Thus, the zooplankton community seems to be more strongly influenced by Candiota natural features like topography and drainage network, except for streams that receive wastewater directly from coal mining.

A bacia hidrográfica do Arroio Candiota está situada no sudoeste do Estado do Rio Grande do Sul, Brasil. Sofre intensa atividade antrópica, como mineração de carvão e calcário, pecuária, silvicultura e agricultura. Apresenta ainda em seu território a Usina Termelétrica Presidente Médici - UTPM - Candiota II. Este trabalho teve como objetivo analisar a variação temporal da comunidade zooplanctônica, representada por Rotifera, Cladocera e Copepoda, a partir das variáveis ambientais e atributos funcionais em alguns arroios impactados pelos diferentes usos da bacia hidrográfica do Arroio Candiota. Foram realizadas coletas trimestrais de água e zooplâncton com o intuito de caracterizar as estações climáticas do ano, durante o período de abril/2007 a outubro/2014. As coletas ocorreram em sete estações amostrais diferentes, totalizando 161 unidades amostrais. As variáveis físicas e químicas selecionadas para este trabalho foram pH, turbidez, ferro dissolvido, oxigênio dissolvido e temperatura. Para as análises estatísticas foram utilizados modelos lineares generalizados (GLM), cálculo da diversidade das espécies, que envolveu duas medidas baseadas em distâncias topológicas, a distinção taxonômica (Δ*) e a diversidade taxonômica (Δ), análise de espécies indicadoras (ISA) e análise de atributos indicadores (ITA). Foram identificados 152 táxons ao total das coletas. Rotifera foi predominante com 122 espécies, após Cladocera com 16 espécies e Copepoda com 14 espécies. Os resultados mostraram que o pH foi a única variável que apresentou resultado significativo com valores positivamente proporcionais para a abundância de espécies. Em relação à riqueza de espécies, as variáveis pH, ferro dissolvido e oxigênio dissolvido influenciaram positivamente ao longo do tempo. O cálculo da diversidade e distinção taxonômica demonstrou que das 161 unidades amostrais, 127 mostraram valores de diversidade conforme o esperado ao acaso na natureza. Quatro unidades amostrais apresentaram valores da diversidade acima do esperado e 31 exibiram valores abaixo do esperado ao acaso. A ISA identificou duas espécies indicadoras da estação amostral 1 e cinco espécies indicadoras da estação amostral 2. Foram encontradas cinco espécies indicadoras específicas do inverno, cinco do outono, quatro da primavera e nove espécies indicadoras no verão. A ITA demonstrou que espécies de tamanho C4 (≥ 1000 μm), tiveram maior ocorrência no inverno e primavera. O atributo funcional “coletores e raspadores” foi considerado indicador para as estações amostrais EA1 e EA3 por cinco espécies. Os resultados encontrados não demonstraram um gradiente contínuo de crescimento ou declínio da abundância e riqueza de espécies ao longo do tempo. Assim, a comunidade zooplanctônica parece ser mais fortemente influenciada pelas características naturais de Candiota, como relevo e rede de drenagem, com exceção dos riachos que recebem diretamente efluentes da mineração de carvão. / The Arroio Candiota watershed is located in the southwestern state of Rio Grande do Sul, Brazil. It suffers intense human activity, such as mining of coal and limestone, livestock, forestry and agriculture. It also presents in its territory the Thermoelectric Plant Presidente Medici - UTPM - Candiota II. This study aimed to analyze the temporal variation of zooplankton community, represented by Rotifers, Cladocera and Copepoda, from the environmental variables and functional attributes in some streams impacted by different uses of the Arroio Candiota watershed. Quarterly sampling of water and zooplankton were conducted in order to characterize the seasons of the year, during the period April/2007 to October/2014. The collections occurred in seven different sampling stations, totaling 161 sampling units. The physical and chemical variables selected for this study were pH, turbidity, dissolved iron, dissolved oxygen and temperature. For statistical analysis we used generalized linear models (GLM), calculating the diversity of species, which involved two measures based on topological distances, the taxonomic distinction (Δ*) and taxonomic diversity (Δ), indicator species analysis (ISA) and indicators atributes analysis (ITA). There were identified 152 taxa to the total collections. Rotifera was predominant with 122 species, 16 species of Cladocera and 14 species of Copepoda. The results showed that pH was the only variable that showed significant results with positive values proportional to the abundance of species. The variables pH, dissolved iron and dissolved oxygen positively influenced the richness of species over time. The calculation of diversity and taxonomic distinction showed that of the 161 sampling units, 127 showed diversity of values as expected at random in nature. Four sampling campaigns showed values of diversity than expected and 31 showed values lower than expected by chance. The ISA has identified two indicator species of the sampling station 1 and 5 indicator species of sampling station 2. We found five specific indicator winter species, five in autumn, four in spring and nine summer indicator species. The ITA has shown that species of C4 size (≥ 1000 μm), were more frequent in winter and spring. The functional attribute "collectors and scrapers" was considered indicator for the sampling stations 1 and 3 with five species. The results did not demonstrate a continuous gradient of growth or decline in abundance and species richness over time. Thus, the zooplankton community seems to be more strongly influenced by Candiota natural features like topography and drainage network, except for streams that receive wastewater directly from coal mining.

A bacia hidrográfica do Arroio Candiota está situada no sudoeste do Estado do Rio Grande do Sul, Brasil. Sofre intensa atividade antrópica, como mineração de carvão e calcário, pecuária, silvicultura e agricultura. Apresenta ainda em seu território a Usina Termelétrica Presidente Médici - UTPM - Candiota II. Este trabalho teve como objetivo analisar a variação temporal da comunidade zooplanctônica, representada por Rotifera, Cladocera e Copepoda, a partir das variáveis ambientais e atributos funcionais em alguns arroios impactados pelos diferentes usos da bacia hidrográfica do Arroio Candiota. Foram realizadas coletas trimestrais de água e zooplâncton com o intuito de caracterizar as estações climáticas do ano, durante o período de abril/2007 a outubro/2014. As coletas ocorreram em sete estações amostrais diferentes, totalizando 161 unidades amostrais. As variáveis físicas e químicas selecionadas para este trabalho foram pH, turbidez, ferro dissolvido, oxigênio dissolvido e temperatura. Para as análises estatísticas foram utilizados modelos lineares generalizados (GLM), cálculo da diversidade das espécies, que envolveu duas medidas baseadas em distâncias topológicas, a distinção taxonômica (Δ*) e a diversidade taxonômica (Δ), análise de espécies indicadoras (ISA) e análise de atributos indicadores (ITA). Foram identificados 152 táxons ao total das coletas. Rotifera foi predominante com 122 espécies, após Cladocera com 16 espécies e Copepoda com 14 espécies. Os resultados mostraram que o pH foi a única variável que apresentou resultado significativo com valores positivamente proporcionais para a abundância de espécies. Em relação à riqueza de espécies, as variáveis pH, ferro dissolvido e oxigênio dissolvido influenciaram positivamente ao longo do tempo. O cálculo da diversidade e distinção taxonômica demonstrou que das 161 unidades amostrais, 127 mostraram valores de diversidade conforme o esperado ao acaso na natureza. Quatro unidades amostrais apresentaram valores da diversidade acima do esperado e 31 exibiram valores abaixo do esperado ao acaso. A ISA identificou duas espécies indicadoras da estação amostral 1 e cinco espécies indicadoras da estação amostral 2. Foram encontradas cinco espécies indicadoras específicas do inverno, cinco do outono, quatro da primavera e nove espécies indicadoras no verão. A ITA demonstrou que espécies de tamanho C4 (≥ 1000 μm), tiveram maior ocorrência no inverno e primavera. O atributo funcional “coletores e raspadores” foi considerado indicador para as estações amostrais EA1 e EA3 por cinco espécies. Os resultados encontrados não demonstraram um gradiente contínuo de crescimento ou declínio da abundância e riqueza de espécies ao longo do tempo. Assim, a comunidade zooplanctônica parece ser mais fortemente influenciada pelas características naturais de Candiota, como relevo e rede de drenagem, com exceção dos riachos que recebem diretamente efluentes da mineração de carvão. / The Arroio Candiota watershed is located in the southwestern state of Rio Grande do Sul, Brazil. It suffers intense human activity, such as mining of coal and limestone, livestock, forestry and agriculture. It also presents in its territory the Thermoelectric Plant Presidente Medici - UTPM - Candiota II. This study aimed to analyze the temporal variation of zooplankton community, represented by Rotifers, Cladocera and Copepoda, from the environmental variables and functional attributes in some streams impacted by different uses of the Arroio Candiota watershed. Quarterly sampling of water and zooplankton were conducted in order to characterize the seasons of the year, during the period April/2007 to October/2014. The collections occurred in seven different sampling stations, totaling 161 sampling units. The physical and chemical variables selected for this study were pH, turbidity, dissolved iron, dissolved oxygen and temperature. For statistical analysis we used generalized linear models (GLM), calculating the diversity of species, which involved two measures based on topological distances, the taxonomic distinction (Δ*) and taxonomic diversity (Δ), indicator species analysis (ISA) and indicators atributes analysis (ITA). There were identified 152 taxa to the total collections. Rotifera was predominant with 122 species, 16 species of Cladocera and 14 species of Copepoda. The results showed that pH was the only variable that showed significant results with positive values proportional to the abundance of species. The variables pH, dissolved iron and dissolved oxygen positively influenced the richness of species over time. The calculation of diversity and taxonomic distinction showed that of the 161 sampling units, 127 showed diversity of values as expected at random in nature. Four sampling campaigns showed values of diversity than expected and 31 showed values lower than expected by chance. The ISA has identified two indicator species of the sampling station 1 and 5 indicator species of sampling station 2. We found five specific indicator winter species, five in autumn, four in spring and nine summer indicator species. The ITA has shown that species of C4 size (≥ 1000 μm), were more frequent in winter and spring. The functional attribute "collectors and scrapers" was considered indicator for the sampling stations 1 and 3 with five species. The results did not demonstrate a continuous gradient of growth or decline in abundance and species richness over time. Thus, the zooplankton community seems to be more strongly influenced by Candiota natural features like topography and drainage network, except for streams that receive wastewater directly from coal mining.

No description available.

Aquatische Gemeinschaften sind stark körpergrößenstrukturiert mit einer exponentiellen Abnahme der Häufigkeit der Individuen mit zunehmender Körpergröße, die als Größenspektrum (SS) bezeichnet wird. Körpergrößenbasierte Ansätze bieten eine einfache und kostengünstige Methode zur Beantwortung komplexer ökologischer Fragestellungen in aquatischer Forschung. Widersprüchliche Ergebnisse zu den wichtigsten Faktoren, die Größenspektren beeinflussen unterstreichen jedoch die Notwendigkeit weiterer Studien. Um einige dieser widersprüchlichen Schlussfolgerungen anzugehen, habe ich eine Reihe von Fragen in den Bereichen Limnologie und Korallenriffökologie untersucht. In dieser Dissertation wurden größenbasierte Ansätze wie SS verwendet, um zu untersuchen, (i) was die Größenverteilung von Zooplankton beeinflusst und ob Zooplankton-fressende Fische (topdown) oder Ressourcenverfügbarkeit und Umweltbedingungen (bottom-up) die SS der Zooplanktongemeinschaft bestimmen, (ii) ob traditionelle Schleppnetze oder moderne hydroakustische Methoden Fisch-SS zuverlässiger darstellen, und (iii) ob SS von Korallenriff- Fischgemeinschaften und die strukturelle Komplexität der Korallen bzw. deren Beziehung zueinander sich unter verschiedenen anthropogenen Stressoren verändert. Zuallererst konnte ich zeigen, dass weder Top-down- noch Bottom-up-Kräfte stark die Größenverteilung der Zooplanktongemeinschaft beeinflussten. Zooplankton SS scheinen robust gegenüber Prädationseffekten zu sein, aber ein empfindlicher Indikator für die Energieverfügbarkeit und Transfereffizienz im Nahrungsnetz des untersuchten Sees. Des Weiteren konnten meine Studien bestätigen, dass hydroakustische Methoden die SS von pelagischen Fischgemeinschaften zuverlässig darstellen, was sie zu einer kostengünstigen und minimalinvasiven Alternative zu traditionellen Fischentnahmemethoden macht. Ich konnte jedoch kein allgemeingültiges Muster hinsichtlich der Größenverteilung von Korallenrifffischen und der strukturellen Komplexität der Korallen in Beziehung zu unterschiedlichen anthropogenen Stressoren finden. Insgesamt zeigt die Dissertation das weite Anwendungsspektrum von SS, um Strukturen und Prozesse in aquatischen Gemeinschaften und Fischfangmethoden zu untersuchen. Die hohe Variabilität von Größenspektren und der Einfluss von Umweltbedingungen unterstreicht weiter die Wichtigkeit, Daten über einen langen Zeitraum einzubeziehen. Darüber hinaus unterstreichen die Ergebnisse dieser Arbeit auch die Grenzen der Anwendung von SS, da für die Beantwortung mancher ökologischer Fragestellungen artenspezifische Informationen, wie Lebensraum- und Nahrungspräferenzen benötigt werden. / Aquatic communities are highly body-size structured with an exponential decline of abundance with increasing body size, which is referred to as the size spectrum (SS). The importance of body size as a principal and simplifying framework within aquatic communities, has led to a high number of theoretical and empirical studies on energy fluxes in food webs and predatorprey interactions using Size Spectra. These size-based approaches offer a rather simple and inexpensive method to answer complex ecological questions. However, conflicting findings on the key drivers of SS highlight the need for further studies. To address some of these conflicting conclusions, I investigated a range of questions within the fields of limnology and coral reef ecology. In this thesis size-based approaches such as SS were employed to explore (i) what drives zooplankton size distribution and whether zooplanktivorous fish (top-down) or resource availability and environmental condition (bottom-up) determine zooplankton community SS, (ii) whether traditional midwater trawling or modern hydroacoustic methods more reliably represent fish SS, and (iii) coral reef fish community SS and habitat structural complexity and their relationship across site-specific anthropogenic stressors. By analysing long term data, I first found that neither top-down or bottom-up forces drove the zooplankton community size distribution. Zooplankton SS seem robust against predation effects but a sensitive indicator for lake-wide energy availability and transfer efficiency in the food web. Then I found that hydroacoustic methods reliably represent pelagic fish community SS, making it a great alternative to traditional and more invasive fish removal sampling methods. Finally, I discovered that coral reef fish SS slope and structural complexity of the reef exhibited a significant negative relationship on two of the examined reef sites which are least exposed to anthropogenic disturbances. A consistent pattern of fish SS and reef complexity was missing, indicating that other environmental factors may also impact the assessed parameters. Overall, my studies show the range of applications of SS to effectively answer universal questions from trophic interactions and the importance of habitat characteristics in a community to a methodological comparison of fish sampling methods. The high variability of SS behaviour and the influence of environmental conditions further underlines the importance to include data on a large temporal scale. Community information, such as taxonomic identity and consideration of species-specific feeding and habitats preferences, for example, are still beneficial in some cases to answer ecologically questions extensively.

No description available.