Made available in DSpace on 2017-07-10T18:13:30Z (GMT). No. of bitstreams: 1 Jose Roberto Mariano.pdf: 761006 bytes, checksum: 1ff3542b379bbf2cc1b28957af1d8d39 (MD5) Previous issue date: 2011-08-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The insertion of culverts in streams may cause habitat degradation, changing patterns of migration and dispersal of species, causing deterioration of biological diversity over time, favoring the disconnection of the habitat. This study aimed to evaluate the fish assemblages between the upstream and downstream segments of box and circular culverts in neotropical streams. Specifically we intend to analyze the composition and structure of the ichthyofauna and its possible spatial patterns, as well as the occurrence of spawning. Sampling for fish fauna were carried out monthly between November 2009 and October 2010, with various fishing gear such as gillnet, sieve, rod and castnet. Samples of ichthyoplankton were conducted between October 2009 and March 2010, with plankton net. During the period 2220 individuals were collected, with 901 fish in segments of circular culvert and 1,310 fish in segments of box culvert, belonging to 33 species. Catches were similar in both upstream and downstream segments of the circular culvert, whereas in the box culvert the fish abundance was just over in the upstream segment against downstream. The Characiformes dominated with a larger number of individuals in the upstream stretch of both culverts. On the other hand, the Siluriformes were abundant in the downstream stretch of the circular culvert, with similar abundances among the sections of box culvert. The richness and diversity of species differed among the sections of circular culvert (higher value in downstream), while values were similar to portions of the box culvert. The most abundant species were Astyanax altiparanae, A. paranae, A. fasciatus, Ancistrus sp., and Hypostomus sp., but with differences in the occurrence of the latter two species: these were more abundant in downstream segment of the circular culvert, and similar in sections of box culvert. The ichthyoplankton sampled was very low, with records of 36 eggs, 05 juveniles and 03 larvae, especially in the downstream section of the culverts. The ichthyofauna obtained distinct patterns among the culverts and in particular between the upstream and downstream sections of circular culvert. The data presented here showed that the circular culvert seems to provoke more limitation to fish movement, acting as a barrier to the species, especially for the Siluriformes, which reflects the variations that exist in abundance, richness and diversity of species. This indicates the need for further studies in neotropical streams intercepted by culverts, aimed to assemblies of fish and their movement. Such studies may subsidize the responsible sectors for the implementation of these structures to propose possible solutions to improve the habitat conditions, adapting the engineering biology of the species. / A implantação de tubulações em riachos pode causar a degradação do habitat, alterando os padrões de migração e dispersão das espécies, gerando deterioração da diversidade biológica ao longo do tempo, favorecendo a desconexão do habitat. O presente estudo teve como objetivo avaliar a influência das assembléias de peixes entre os segmentos de montante e jusante de tubulações quadrada e circular em riachos neotropicais. Especificamente pretende-se analisar a composição e a estrutura das da ictiofauna e seus possíveis padrões espaciais, bem como a ocorrência de desovas. As amostragens para a ictiofauna foram realizadas mensalmente, entre novembro de 2009 e outubro de 2010, com diversos apetrechos de pesca como rede, peneirão, caniço e tarrafa. As amostragens do ictioplâncton foram realizadas entre o outubro de 2009 e março de 2010, com uma rede de plâncton. Durante o período foram coletados 2.220 indivíduos, sendo 901 peixes nos trechos da tubulação circular e 1.310 peixes nos trechos da tubulação quadrada, pertencentes a 33 espécies. As capturas foram semelhantes nos trechos de montante e jusante na tubulação circular, enquanto que para a tubulação quadrada a abundância de peixes foi um pouco superior no trecho a montante em relação a jusante. Os Characiformes predominaram com maior número de indivíduos no trecho a montante de ambas as tubulações. Por outro lado, os Siluriformes foram abundantes no trecho a jusante da tubulação circular, com abundâncias similares entre os trechos da tubulação quadrada. A riqueza e a diversidade de espécies diferiram entre os trechos da tubulação circular (maior valor a jusante), enquanto que os valores foram similares para os trechos da tubulação quadrada. As espécies mais abundantes foram Astyanax altiparanae, A. paranae, A. fasciatus, Ancistrus sp. e Hypostomus sp., porém com diferenças constatadas na ocorrência das duas últimas espécies: estas foram mais abundantes a jusante da tubulação circular, e similares nos trechos da tubulação quadrada. O ictioplâncton amostrado foi pouco expressivo, com registros de 36 ovos, 05 jovens e 03 larvas especialmente no trecho de jusante das tubulações. A ictiofauna obteve padrões distintos entre as tubulações e em especial entre os trechos de montante e jusante da tubulação circular. Os dados aqui apresentados evidenciam que a tubulação circular parece exercer maior limitação ao movimento dos peixes, atuando como uma barreira para as espécies, em especial aos Siluriformes, o que reflete nas variações existentes na abundância, riqueza e diversidade das espécies. Isso indica a necessidade de maiores estudos em riachos neotropicais interceptados por tubulações, voltados às assembleias de peixes e sua movimentação. Esses estudos poderão subsidiar os setores responsáveis pela implantação dessas estruturas no sentido de propor possíveis soluções para a melhoria das condições dos habitats, adequando a engenharia a biologia das espécies.

Swimming performance strongly influences fitness in aquatic organisms and is closely tied to external body morphology. Although this connection has been closely examined at the individual and species level, few studies have focused on this relationship as it pertains to functional group assemblages. Using functional groups based on similarities in habitat use and morphology, I tested the hypothesis that swimming performance can be reliably predicted by functional group composition. I measured swimming performance as burst speed using a simulated predator attack and as prolonged speed using a step-endurance test in a laboratory flume. I measured morphology using geometric morphometric techniques. A difference in swimming behavior in four of the seven species was observed in the step-endurance test. Benthic species exhibited bracing behavior as an alternative to body-caudal fin (BCF) propulsion in the prolonged speed trials. Swimming performance exhibited a weak relationship with functional groups based on habitat or morphology. Rather a species-based model was the best predictor of swimming performance. Although species exhibited variation in swimming performance, body size was the strongest predictor of absolute swimming performance across all models. Relative swimming performance (measured in body lengths/sec) was negatively related to body size. The results of this study suggest that functional groups are not always reliable predictors of performance and they necessitate empirical testing to validate their effectiveness. This study also provides critical swimming performance data for previously unstudied Great Basin fishes which could be valuable for predicting fish passage through culverts, weirs and fish ladders.

As replacement and removal of undersized culverts gains momentum as an effective technique for restoring natural stream flows and removing fish passage barriers, it is important to evaluate the benefits of these efforts on the in-stream and adjacent riparian habitat for other species of potential concern. This study compares stream-associated amphibian (SAA) occurrence in streams adjacent to different road crossing structures on unpaved forest roads in the Wilson River watershed located within the Tillamook State Forest, Oregon. Surveys were conducted at road crossing structures for three taxa of SAA; Pacific giant salamander (Dicamptodon tenebrosus), coastal tailed frog (Ascaphus truei), and Columbia torrent salamander (Rhyacotriton kezeri). Statistical models were created to analyze the effect of habitat variables on SAA occupancy, and determine whether those variables changed relative to road crossing structures. Results showed that coastal tailed frog occupancy was positively associated with dissolved oxygen and crayfish presence, negatively associated with longitude, and had a slight quadratic relationship to channel confinement. Because all sites were highly saturated with oxygen, percent dissolved oxygen was likely a surrogate for one or more other covariates, such as in-stream habitat or substrate size. Detection rates of Pacific giant salamander were too high and detection rates of Columbia torrent salamander were too low to provide reliable models, but they did provide some insight into the factors affecting occupancy in the study area, including information about their interactions with road crossing structures. Occupancy rates of Pacific giant salamanders in the study area appear to be unaffected by road crossings, fish passable or otherwise. Conversely, torrent salamanders seemed to be mostly absent from the study sites altogether, but based on the one stream where they were detected, they are not excluded from occupying fish barrier culvert sites. Top weighted habitat covariates, including dissolved oxygen, channel confinement, crayfish and fish presence, and flow constriction are all indicators of disturbance that can be linked to road crossings. Although the size and structure of road crossings did not prove to significantly influence SAA occupancy, indicators of stream disturbance that can be related to road crossings were included in the best models for predicting occupancy, demonstrating the importance of reducing disturbance related to road crossings on streams.