Made available in DSpace on 2014-06-11T19:30:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-05-08Bitstream added on 2014-06-13T20:40:03Z : No. of bitstreams: 1 goncalves_cs_me_rcla.pdf: 1337384 bytes, checksum: 94cd3ab8a80a89526260a33dfb24ee7a (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Estudos sobre alimentação natural de peixes contribuem para o conhecimento básico da biologia das espécies, compreensão da organização trófica do ecossistema e conhecimento das interações entre as espécies. O presente estudo visou estudar a biologia alimentar da ictiofauna na área de influência do reservatório da usina Mogi Guaçu e nas lagoas marginais naturais da Estação Ecológica (fazenda Campininha), município de Mogi Guaçu-SP, com o intuito de responder as seguintes questões: (1) quais recursos alimentares as espécies estão utilizando? (2) existe alguma preferência alimentar para as espécies? (3) ocorrem alterações sazonais na dieta das espécies? Para a captura dos peixes, foram utilizadas redes de espera, puçá e armadilhas do tipo covo. Foram capturados 2341 exemplares de 41 espécies pertencentes a cinco ordens e 15 famílias. A ictiofauna nos ambientes estudados foi composta por peixes típicos da bacia do alto Paraná indicando uma condição que, embora alterada, apresenta espécies essencialmente nativas desta região. Foram analisados 370 estômagos provenientes de 1900 exemplares de peixes pertencentes a 14 espécies nos dois ambientes. Entre os itens consumidos pelos peixes, detritos e insetos (fragmentos) foram os que mais contribuíram para a alimentação das espécies no reservatório e nas lagoas marginais, respectivamente. Verificou-se que a dieta das espécies no reservatório e nas lagoas marginais foi significativamente correlacionada entre os períodos seco e chuvoso não ocorrendo, portanto, alterações sazonais. Os itens de origem autóctone tiveram uma participação maior na dieta das espécies, incluindo algas, insetos aquáticos e detritos entre os mais freqüentes. Foram determinadas cinco guildas tróficas para as 17 espécies analisadas. No reservatório os curimatídeos compuseram a guilda... / Studies involving fishes natural feeding habits increases the knowledge about species biology, understanding the trophic structure and species interaction. This work was conducted to study the feeding biology of fishes from Mogi Guaçu reservoir and some oxbow lakes from a protected area known by fazenda Campininha (Mogi Guaçu municipality), to answer the following questions: (1) which food resources fishes are using? (2) is there any food resource preferred for them? (3) seasonal alterations occur in fishes diets? Fishes were sampled using simple gillnets with different meshes sizes and traps. We captured 2341 fishes from 41 species belonging five orders and 15 families. The fish fauna composition revealed typical species from high Paraná river system indicating the presence of native species although the human alterations in the region. We analyzed 370 stomachs from 1900 individuals (14 species from both areas). They consumed mostly detritus and insects (fragments). Fishes diet on reservoir and oxbow lakes were significantly correlated between the seasons and no changes were observed. The majority items consumed were from autochthonous origin, including algae, aquatic insects and detritus that appeared frequently. Five trophic guilds were determined to the 17 species sampled. Curimatidae were the most abundant species corresponding to detritivorous fishes, followed by omnivorous, invertivorous, piscivorous and herbivorous fishes. Four trophic guilds were found in oxbow lakes where the invertivorous fishes were the most abundant (Hoplosternum littorale, Hyphessobrycon bifasciatus and Hyphessobrycon eques), followed by detritivorous, omnivorous and piscivorous fishes. The frequencies obtained from stomach repletion, fat accumulation and gonadal maturation degrees were related with fish's conditions.

Orientador: Francisco Manoel de Souza Braga / Banca: Norma Segatti Hahn / Banca: Francisco Langeani Neto / Resumo: Estudos sobre alimentação natural de peixes contribuem para o conhecimento básico da biologia das espécies, compreensão da organização trófica do ecossistema e conhecimento das interações entre as espécies. O presente estudo visou estudar a biologia alimentar da ictiofauna na área de influência do reservatório da usina Mogi Guaçu e nas lagoas marginais naturais da Estação Ecológica (fazenda Campininha), município de Mogi Guaçu-SP, com o intuito de responder as seguintes questões: (1) quais recursos alimentares as espécies estão utilizando? (2) existe alguma preferência alimentar para as espécies? (3) ocorrem alterações sazonais na dieta das espécies? Para a captura dos peixes, foram utilizadas redes de espera, puçá e armadilhas do tipo covo. Foram capturados 2341 exemplares de 41 espécies pertencentes a cinco ordens e 15 famílias. A ictiofauna nos ambientes estudados foi composta por peixes típicos da bacia do alto Paraná indicando uma condição que, embora alterada, apresenta espécies essencialmente nativas desta região. Foram analisados 370 estômagos provenientes de 1900 exemplares de peixes pertencentes a 14 espécies nos dois ambientes. Entre os itens consumidos pelos peixes, detritos e insetos (fragmentos) foram os que mais contribuíram para a alimentação das espécies no reservatório e nas lagoas marginais, respectivamente. Verificou-se que a dieta das espécies no reservatório e nas lagoas marginais foi significativamente correlacionada entre os períodos seco e chuvoso não ocorrendo, portanto, alterações sazonais. Os itens de origem autóctone tiveram uma participação maior na dieta das espécies, incluindo algas, insetos aquáticos e detritos entre os mais freqüentes. Foram determinadas cinco guildas tróficas para as 17 espécies analisadas. No reservatório os curimatídeos compuseram a guilda... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Studies involving fishes natural feeding habits increases the knowledge about species biology, understanding the trophic structure and species interaction. This work was conducted to study the feeding biology of fishes from Mogi Guaçu reservoir and some oxbow lakes from a protected area known by fazenda Campininha (Mogi Guaçu municipality), to answer the following questions: (1) which food resources fishes are using? (2) is there any food resource preferred for them? (3) seasonal alterations occur in fishes diets? Fishes were sampled using simple gillnets with different meshes sizes and traps. We captured 2341 fishes from 41 species belonging five orders and 15 families. The fish fauna composition revealed typical species from high Paraná river system indicating the presence of native species although the human alterations in the region. We analyzed 370 stomachs from 1900 individuals (14 species from both areas). They consumed mostly detritus and insects (fragments). Fishes diet on reservoir and oxbow lakes were significantly correlated between the seasons and no changes were observed. The majority items consumed were from autochthonous origin, including algae, aquatic insects and detritus that appeared frequently. Five trophic guilds were determined to the 17 species sampled. Curimatidae were the most abundant species corresponding to detritivorous fishes, followed by omnivorous, invertivorous, piscivorous and herbivorous fishes. Four trophic guilds were found in oxbow lakes where the invertivorous fishes were the most abundant (Hoplosternum littorale, Hyphessobrycon bifasciatus and Hyphessobrycon eques), followed by detritivorous, omnivorous and piscivorous fishes. The frequencies obtained from stomach repletion, fat accumulation and gonadal maturation degrees were related with fish's conditions. / Mestre

<p>This dissertation investigates the limnology of the southwestern Peruvian Amazon centered on the Madre de Dios department by examining first the geomorphology and then the ecology and biogeochemistry of the region's fluvial systems. </p><p>Madre de Dios, Peru is world renowned for its prolific biodiversity and its location within the Andes biodiversity hotspot. It is also a site of study regarding the development of the Fitzcarrald Arch and that feature's geomorphological importance as the drainage center for the headwaters of the Madeira River - the Amazon's largest tributary and as well as its role as a physical divider of genetic evolution in the Amazon. Though each of these has been studied by a variety of prominent researchers, the ability to investigate all the aspects of this unique region is hampered by the lack of a regional geomorphological map. This study aims to fill that gap by using remote sensing techniques on digital elevation models, satellite imagery and soil, geology and geoecological maps already in publication to create a geomorphological map. The resulting map contains ten distinct landform types that exemplify the dominance of fluvial processes in shaping this landscape. The river terraces of the Madre de Dios River are delineated in their entirety as well as the various dissected relief units and previously undefined units. The demarcation of the boundaries of these geomorphic units will provide invaluable assistance to the selection of field sites by future researchers as well as insights into the origin of the high biodiversity indices of this region and aid in planning for biodiversity conservation. </p><p>Secondly this study examines 25 tropical floodplain lakes along 300 km of the Manu River within the Manu National Park in the Madre de Dios department. Alternative stable state and regime shifts in shallow lakes typically have been examined in lakes in temperate and boreal regions and within anthropogenically disturbed basins but have rarely been studied in tropical or in undisturbed regions. In contrast this study focuses on a tropical region of virtually no human disturbance and evaluates the effects of hydrological variability on ecosystem structure and dynamics. Using satellite imagery a 23 yr timeline of ecological regime shifts in Amazon oxbow lakes or "cochas" is reconstructed. The study shows that almost 25% of the river's floodplain lakes experience periodic abrupt vegetative changes with an average 3.4% existing in an alternative stable state in any given year. State changes typically occur from a stable phytoplankton-dominated state to a short lived, <3 yr, floating macrophytic state and often occur independent of regional flooding. We theorize that multiple dynamics, both internal and external, drive vegetative regime shifts in the Manu but insufficient data yet exists in this remote region to identify the key processes. </p><p>To complete the investigation of tropical limnology the third study compares and contrasts the nutrient-productivity ration of floodplain and non-floodplain lakes globally and regionally. For over 70 years a strong positive relationship between sestonic chlorophyll-a (Chl-a) and total phosphorus (TP) has been established with phosphorus generally viewed as the most limiting factor to productivity. Most of these studies, however, have focused on northern, temperate regions where the lakes are typically postglacial, isolated and fed by small streams. Relatively little work has been done on floodplain lakes which are semi or permanently connected to the river. This study examines the relationship between nutrients and productivity in floodplain lakes globally through an extensive literature synthesis. Values for total phosphorus, total nitrogen and chlorophyll-a were collected for 523 floodplain lakes, represented by 288 data points while 551 data points were collected for 5444 non-floodplain lakes. Analysis revealed that globally, floodplain lakes do not show any significant difference in the total phosphorus/chlorophyll-a relationship from that found in non-floodplain lakes but significant differences are seen between tropical and temperate lakes. We propose that the term `floodplain' lake should serve as purely a geographical descriptor and that it is lacking as an ecological indicator. Instead factors such as precipitation seasonality, hydrological connectivity and regional flooding regimes are better indicators of high or low productivity in floodplain lakes.</p> / Dissertation

Fish community data were used to develop an index of biotic integrity (IBI) to quantify habitat degradation in oxbow lakes of the Delta region of the Yazoo River Basin. Daytime boat electrofishing was used to sample the fish assemblage of 30 oxbow lakes during 2006-2007. We evaluated 70 candidate metrics based on their responses to measures of anthropogenic disturbance. Six metrics were retained for inclusion in the IBI: species richness, Shannon’s diversity (H’), average tolerance, and catch rates of buffalo, orangespotted sunfish, and litho-psammophilic spawners. The six IBI metrics showed strong multivariate relationships with measures of habitat degradation in a canonical correlation analysis. Spearman’s rank correlation and scatterplot analysis showed that IBI scores changed in a predictable pattern along gradients of habitat degradation. Three additional lakes were sampled in 2008 and were used to successfully validate the IBI. Biotic integrity was found to be impaired in most oxbow lakes of the Mississippi Delta.

Submitted by Ligia Roma Stephan null (ligia.roma@terra.com.br) on 2017-12-03T17:29:12Z No. of bitstreams: 1 Tese Doutorado Ligia R. Stephan.pdf: 1678102 bytes, checksum: 963311d73c5a4e54a01169c577b6df61 (MD5) / Approved for entry into archive by Elza Mitiko Sato null (elzasato@ibilce.unesp.br) on 2017-12-04T14:10:00Z (GMT) No. of bitstreams: 1 stephan_lr_dr_sjrp.pdf: 1678102 bytes, checksum: 963311d73c5a4e54a01169c577b6df61 (MD5) / Made available in DSpace on 2017-12-04T14:10:00Z (GMT). No. of bitstreams: 1 stephan_lr_dr_sjrp.pdf: 1678102 bytes, checksum: 963311d73c5a4e54a01169c577b6df61 (MD5) Previous issue date: 2017-10-20 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Neste estudo foi avaliada a importância das características limnológicas locais e da predação por peixes na estrutura das comunidades zooplanctônicas, sendo os objetivos e resultados apresentados em dois capítulos distintos: Capítulo 1. Tem por objetivo avaliar a influência dos pulsos de inundação na estrutura funcional e taxonômica das comunidades de microcrustáceos em lagoas marginais. Para atingir o objetivo proposto, foram determinadas a estrutura funcional e taxonômica das assembleias de microcrustáceos coletadas em lagoas marginais ao Rio Turvo em três estações distintas: seca, intermediária e chuvosa. Os resultados encontrados foram comparados entre lagoas e entre estações; também foram comparadas a estrutura das asssembléias das lagoas marginais com amostras de microcrustáceos provenientes de ambientes lênticos com diferentes regimes hidrológicos. Neste estudo também foi avaliado se um período longo de estiagem pode influenciar as dinâmicas sazonais dos microcrustáceos. A estrutura das assembleias dos microcrustáceos com base na classificação funcional e taxonômica apresentaram variações entre lagoas e estações, assim como ambientes aquáticos que não sofrem influência dos pulsos de inundação apresentam uma maior uniformidade funcional. A dinâmica sazonal das assembleias foi afetada pelo período prolongado de estiagem, onde as variações na estrutura das comunidades que existem entre estações foram menos intensas no período de estiagem quando comparado ao ano chuvoso. Os resultados mostram que as características limnológicas das lagoas são influenciadas pelos pulsos de inundação e pelo regime hidrológico, bem como um período prolongado de estiagem é capaz de influenciar a dinâmica sazonal das assembléias de microcrustáceos em lagoas marginais. O estudo também mostra que há uma grande heterogeneidade funcional entre as lagoas, sugerindo que o padrão encontrado para a comunidade zooplanctônica revela mais a importância das características locais associadas ao pulso de inundação do que os efeitos deste sobre a comunidade de toda a planície. Capítulo 2. O segundo capítulo tem por objetivo avaliar se a predação por 6 peixes pode influenciar a estrutura funcional das assembleias de microcrustáceos. A influência da predação sobre a comunidade de microcrustáceos foi avaliada por meio de um experimento de mesocosmo e pela avaliação do conteúdo estomacal dos peixes provenientes das lagoas marginais ao Rio Turvo. A abundância e a estrutura funcional dos microcrustáceos foram influenciadas pela presença dos peixes e das macrófitas aquáticas no experimento, entretanto, para as análises realizadas nas lagoas marginais os resultados mostram que a predação não possui um efeito capaz de influenciar a estrutura das assembleias. Como conclusão, podemos inferir que a presença dos peixes pode ser um fator estruturador das comunidades, mas que em ambientes dinâmicos tais como as lagoas marginais, a influência exercida por alterações nas características locais pode ser um fator mais intenso na estruturação das assembleias de microcrustáceos do que a predação por peixes. / In this study, the importance of local characteristics and predation by fish in the zooplankton community structure was evaluated. The objectives and results were separated in two distinct chapters: Chapter 1. Its objective is to evaluate the influence of flood pulses on the functional and taxonomic structure of microcrustacean communities in oxbow lakes. For the proposed objective, the functional and taxonomic structure of the microcrustacean assemblages from oxbow lakes to the Rio Turvo was determined in three seasons: dry, intermediate and rainy. The results were compared between oxbow lakes and between seasons, as well as between samples from environments with different hydrological regimes. In this study, it was also evaluated if a long period of drought can influence the seasonal dynamics of microcrustaceans. The structure of the microcrustacean assemblages based on the functional and taxonomic classification showed variations between oxbow lakes and seasons; a greater functional uniformity was found on the aquatic environments not influenced by the flood pulses. The seasonal dynamics of the assemblages was affected by the prolonged period of drought, where the variations in the structure of communities between seasons were less intense in the drought year when compared to the rainy year. Our results show the influence of flood pulses on limnological characteristics and on the functional and taxonomic assemblages of microcrustaceans in the oxbow lakes; we also observed that a prolonged period of drought is able to influence the seasonal dynamics of microcrustacean assemblages in oxbow lakes. Chapter 2. The second chapter aims to assess the influence of fish predation on the functional structure of microcrustacean assemblages. The influence of fish predation was evaluated through an mesocosm experiment, and through an evaluation of fish stomach contents sampled in the marginal lakes from Turvo River. In the experiment, the abundance and functional structure of the microcrustaceans were influenced by the presence of fish and aquatic macrophytes, however, results from the oxbow lakes show that predation does not have an effect capable to incluence the structure of the microcrustaceans assemblages. As conclusion, fish predation should have a role in the 8 structure of the communities, although in dynamic environments such as oxbow lakes, the influence of the local characteristics may be a more important factor in the structuring of the microcrustacean assemblages then the fish predation.

This research investigated hydrologic connectivity, the intricate network of water pathways linking waterbodies, and its implications for biodiversity exchange in floodplains. Chapter 1 provides an exhaustive literature review encompassing factors influencing hydrologic connectivity, assessment approaches, scales, challenges, and management tools. Existing research often focuses on single scales and short-term periods, revealing a need for comprehensive multi-scale and extended temporal analyses. The absence of standardized definitions and methodologies in this field is also considered. Chapter 2 presents an innovative approach quantifying eight key connectivity metrics using remote sensing and GIS within the Lower Mississippi Alluvial Valley (LMAV). This adaptable method assesses connectivity between oxbow lakes and varying stream sizes, revealing spatial variability within the LMAV and enhancing scientific understanding of connectivity dynamics while ensuring portability. This research is crucial for effective ecosystem management and targeted conservation efforts, particularly regarding invasive species like the bigheaded carps (Hypophthalmichthys spp.).