Made available in DSpace on 2015-05-14T16:52:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-03-12Bitstream added on 2015-05-14T16:59:41Z : No. of bitstreams: 1 000829504.pdf: 1230516 bytes, checksum: b7d237b03a2512a50543b61b02ab9478 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O objetivo deste trabalho foi caracterizar a estrutura e a composição da ictiofauna do rio Sapucaí-Mirim (SP), em trechos que sofrem interferência direta de Pequenas Centrais Hidroelétricas (PCH´s) dispostas em cascata no eixo principal do rio. Da montante para jusante as PCH’s estão dispostas da seguinte maneira: Palmeiras, Anhanguera e Retiro (em construção durante a execução da pesquisa). Novas PCHs estão previstas tanto no trecho superior como no trecho inferior do rio. Foram realizadas oito campanhas amostrais, considerando oito diferentes locais, com periodicidade trimestral de junho/2011 a março/2013. Como aparato de captura, foram utilizadas redes de emalhar com malhas variando de 3 a 18 cm entre nós opostos, todas com 20 m de comprimento e altura variando de 1,5 a 2,0 m, totalizando 450 m² por local de amostragem. Foram identificados 66 táxons de peixes, distribuídos em seis ordens, 19 famílias e 41 gêneros. A ordem mais especiosa foi a Characiformes (29 espécies), pelos Siluriformes (25), Perciformes (seis), Gymnotiformes (quatro), Synbranchiformes e Cyprinodontiformes (um táxon cada). O rio Sapucaí-Mirim se mostrou altamente especioso em relação ao tamanho reduzido de sua bacia de drenagem. A composição da ictiofauna na área de influência dos reservatórios segue o mesmo padrão de composição de grandes barragens, com proliferação de espécies de pequeno porte, com alto potencial reprodutivo e baixa longevidade. No caso do rio Sapucaí-Mirim destaca-se ainda a expressiva abundância e riqueza de cascudos, cujas populações podem ser afetadas pela perda de habitats fluviais típicos utilizados por esses organismos (pedrais, corredeiras). Já a distribuição espacial dos peixes dentro dos reservatórios das PCHs difere dos grandes represamentos, devido às diferentes proporções de tamanho dos compartimentos formados. Não foram identificados padrões claros que demonstrem a interferência direta das ... / The aim of this study was to characterize the composition and structure of the ichthyofauna of the Sapucaí - Mirim River (SP) in stretches under direct interference of Small Hydropower Plants (SHP’s), which are disposed in a cascade system along the river main axis. From upstream to downstream the sequence of SHP’s are: Palmeiras, Anhanguera and Retiro (under construction during the investigation). New plants are to be constructed, in the superior and inferior river stretches. Eight sampling campaigns, considering eight sampling points, were conducted quarterly from June/2011 until March/2013. As capture apparatus, gillnets were used with meshes ranging from 3 to 18cm between opposite knots, all with 20m length and height ranging 1.5 to 2.0 m, totaling 450 m² per sampling site. Sixty-six taxa of fishes were identified and distributed in six orders, 19 families and 41 genus. The most specious order was Characiformes (29 species), followed by Siluriformes (25), Perciformes (six), Gymnotiformes (four), Synbranchiformes and Cyprinodontiformes orders (one taxon each). The Sapucaí-Mirim is a highly specious river, considering its limited drainage area. The ichthyofauna composition in the areas under reservoirs influence follows the same pattern observed in large dams, with proliferation of small size species with high reproductive potential and reduced longevity. It is also noticeable for Sapucaí River the expressive richness and abundance of catfishes. These fish group is highly dependent on typical fluvial habitats threatened by dam construction, such as the riffles. The fish spatial distribution did not follow the pattern observed in large impoundments, probably due the reduced effect of reservoir compartmentalization in case of SHPs. Our results did not evidence the direct interference of SHPs construction on the ichthyofauna. Therefore, it is of fundamental importance to increase the monitoring area along the river, not only ...

Orientador: Marcos Gomes Nogueira / Coorientador: Sandro Geraldo de Castro Britto / Banca: João Henrique Pinheiro Dias / Banca: Ana Paula Vidotto Magnoni / Resumo: O objetivo deste trabalho foi caracterizar a estrutura e a composição da ictiofauna do rio Sapucaí-Mirim (SP), em trechos que sofrem interferência direta de Pequenas Centrais Hidroelétricas (PCH's) dispostas em cascata no eixo principal do rio. Da montante para jusante as PCH's estão dispostas da seguinte maneira: Palmeiras, Anhanguera e Retiro (em construção durante a execução da pesquisa). Novas PCHs estão previstas tanto no trecho superior como no trecho inferior do rio. Foram realizadas oito campanhas amostrais, considerando oito diferentes locais, com periodicidade trimestral de junho/2011 a março/2013. Como aparato de captura, foram utilizadas redes de emalhar com malhas variando de 3 a 18 cm entre nós opostos, todas com 20 m de comprimento e altura variando de 1,5 a 2,0 m, totalizando 450 m² por local de amostragem. Foram identificados 66 táxons de peixes, distribuídos em seis ordens, 19 famílias e 41 gêneros. A ordem mais especiosa foi a Characiformes (29 espécies), pelos Siluriformes (25), Perciformes (seis), Gymnotiformes (quatro), Synbranchiformes e Cyprinodontiformes (um táxon cada). O rio Sapucaí-Mirim se mostrou altamente especioso em relação ao tamanho reduzido de sua bacia de drenagem. A composição da ictiofauna na área de influência dos reservatórios segue o mesmo padrão de composição de grandes barragens, com proliferação de espécies de pequeno porte, com alto potencial reprodutivo e baixa longevidade. No caso do rio Sapucaí-Mirim destaca-se ainda a expressiva abundância e riqueza de cascudos, cujas populações podem ser afetadas pela perda de habitats fluviais típicos utilizados por esses organismos (pedrais, corredeiras). Já a distribuição espacial dos peixes dentro dos reservatórios das PCHs difere dos grandes represamentos, devido às diferentes proporções de tamanho dos compartimentos formados. Não foram identificados padrões claros que demonstrem a interferência direta das ... / Abstract: The aim of this study was to characterize the composition and structure of the ichthyofauna of the Sapucaí - Mirim River (SP) in stretches under direct interference of Small Hydropower Plants (SHP's), which are disposed in a cascade system along the river main axis. From upstream to downstream the sequence of SHP's are: Palmeiras, Anhanguera and Retiro (under construction during the investigation). New plants are to be constructed, in the superior and inferior river stretches. Eight sampling campaigns, considering eight sampling points, were conducted quarterly from June/2011 until March/2013. As capture apparatus, gillnets were used with meshes ranging from 3 to 18cm between opposite knots, all with 20m length and height ranging 1.5 to 2.0 m, totaling 450 m² per sampling site. Sixty-six taxa of fishes were identified and distributed in six orders, 19 families and 41 genus. The most specious order was Characiformes (29 species), followed by Siluriformes (25), Perciformes (six), Gymnotiformes (four), Synbranchiformes and Cyprinodontiformes orders (one taxon each). The Sapucaí-Mirim is a highly specious river, considering its limited drainage area. The ichthyofauna composition in the areas under reservoirs influence follows the same pattern observed in large dams, with proliferation of small size species with high reproductive potential and reduced longevity. It is also noticeable for Sapucaí River the expressive richness and abundance of catfishes. These fish group is highly dependent on typical fluvial habitats threatened by dam construction, such as the riffles. The fish spatial distribution did not follow the pattern observed in large impoundments, probably due the reduced effect of reservoir compartmentalization in case of SHPs. Our results did not evidence the direct interference of SHPs construction on the ichthyofauna. Therefore, it is of fundamental importance to increase the monitoring area along the river, not only ... / Mestre

Fifty-three basins with area less than 9.40 km² were mapped from 1:25,000-scale aerial photographs to provide data on basin morphometry. A significantly larger number of first-order streams exist than are expected according to the regression of stream number on order for each basin. This is attributed to the incorporation of recently formed gullies into the stream network as first-order streams. Most drainage density (Dd) values are in the coarse texture category (Dd<5.0 km/km²). Higher values of Dd correspond to areas of shallow soils. Total stream frequency (F[subscribe t]) and first-order stream frequency (F₁) are closely correlated with Dd (r=+0.86 and r=+0.89, respectively), but third-order stream frequency (F₃) is not (r=+0.70). F[subscribe t] is related to Dd as follows: F[subscribe t]=0.704 (Dd)²̇⁰⁸. Values of ruggedness number (HDd) and basin magnitude indicate that all basins are high-flood potential basins. This imposes serious limitations on the development of the watershed as a whole. Weighted mean percent silt-clay (M) and channel width-depth ratio (F) for 21 cross sections of stream channels were used to define cross section stability. Catchment area above each cross section is related to its stability. As area increases cross sections change from degrading to aggrading to stable conditions. There is a more gradual increase in F with decreasing M than in streams in the mid-western United States. This is attributed to the vigorous vegetation which stabilizes channel banks in the Mandaguari watershed. Recent climatic changes in the region rendered colluvial deposits susceptible to increased erosion under the present subtropical (Cwa) climate. When saturated, the latosols and podzols there are easily eroded owing to their low cohesion (PI=0-15). Recent deforestation and seasonal burning of pastures probably exacerbate this condition, contributing to the erosion of hillsides and the formation of gullies. Large, aggressive gullies (voçorocas) 10-15 m deep and 30-40 m wide occur in association with urban centers. Management of the Riberão do Mandaguari watershed should be based on considerations of (1) threshold conditions for instability of stream channel cross sections and soils and (2) complex responses of the watershed. Recommended actions are reforestation of slopes at and above the point of maximum profile steepness, induced incision of channel filling deposits, and control of runoff from urban centers. / text