A obra literária: ecologia de ambientes lóticos

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Regime alimentar, distribuição espacial e temporal de peixe (teleostei) em um riacho na região de Limeira, São Paulo

Orientador: Ivan SazimaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de BiologiaResumo: O regime alimentar, a distribuição estacional, espacial e temporal e alguns aspectos da morfologia, foram examinados para dezoito espécies de peixes do ribeirão do Tabajara, Limeira, São Paulo. Os peixes de um trecho, de aproximadamente 100 m, do ribeirão do Tabajara foram coletados bimestralmente, de novembro de 1979 a outubro de 1980. Na comunidade estudada, oito espécies, representando 44,4% do total de espécies coletadas, estiveram presentes no riacho o ano todo. Esta comunidade residente era composta por Paroligosarcus pintoi, Geophagus brasiliensis, Cichlasoma facetum, Astyanax bimaculatus, Hypostomus ancistroides, Curimata gilberti, Characidium cf. fasciatum e Hyphessobrycon anisitsi. As demais espécies (55,6%) juntavam-se à comunidade residente somente em certas épocas do ano, levando assim a uma variação estacional na composição da comunidade. Algumas destas espécies, consideradas imigrantes, foram coletadas somente na estação chuvosa (Hoplias malabaricus, Gymnotus carapo, Holoshesthes heterodon, Tilapia rendalli e Synbranchus marmoratus), outras somente na estação seca (Astyanax eigenmanniorum, Astyanax scabripinnis e Bryconamericus sp.) e outras tanto na estação chuvosa como na seca (Rhamdia cf. hilarii e Rhamdella minuta). Para A. heterodon, S. marmoratus, A. eigenmanniorum e A. scabripinnis, devido ao pequeno número de indivíduos coletados ao longo do ano (menos de 5 para cada espécie), não é seguro concluir que tem sua ocorrência, no ribeirão do Tabajara, concentrada somente na estação chuvosa ou na estação seca... Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digitalAbstract: The food habits, seasonal, spatial and temporal distributions and some aspects of the morphology were examined for eighteen species of fishes of the ribeirão do Tabajara, Limeira, São Paulo. The fishes of a stretch (approximately 100 m) of the ribeirão do Tabajara were collected bimonthly, between November 1979 and October 1980. In the community studied, eight species, representing 44,4% of the total species sampled, were present in the stream all of the year. This resident community was composed of: Paroligosarcus pintoi, Geophagus brasiliensis, Cichlasoma facetum, Astyanax bimaculatus, Hypostomus ancistroides, Curimata gilberti, Characidium cf. fasciatum and Hyphessobrycon anisitsi. The other species (55,6%) joined the resident community only at certain times, thus determining the seasonal changes in the species composition of this community. Some of these species, considered immigrants, were collected only in the wet season (Hoplias malabaricus, Gymnotus carapo. Holoshesthes heterodon. Tilapia rendalli and Synbranchus marmoratus). others only in the dry season (Astyanax eigenmanniorum, Astyanax scabripinnis and Bryconamericus sp.) and others both in the wet and dry season (Rhamdia cf. hilarii and Rhamdella minuta). For A. heterodon, S. marmoratus, A. eigenmanniorum and A. scabripinnis it is not possible to conclude that these species occurred in the ribeirão do Tabajara only at the wet season or at the dry season because few specimens (less than five of each species) were caught along the year... Note: The complete abstract is available with the full electronic digital thesis or dissertationsMestradoMestre em Ecologi

Comunidade de peixes de um riacho litoraneo : composição, habitat e habitos

Orientador: Ivan SazimaTese (doutorado) - Universidade Estadual de Campinas, Instituto de BiologiaResumo: Não informadoAbstract: Not informed.DoutoradoDoutor em Ecologi

Composição da Ictiofauna de quatro trechos de diferentes ordens do Rio Capivara, Bacia do Tietê, Botucatu, São Paulo

The present work aims at characterizing the ichthyofauna of the Capivara River, the most important tributary of the left margin of Middle Tietê River Basin (State of São Paulo, Brazil), in four sections: one of firstorder, one of third-order and two of fourth-order. The first two sections are located on the top of the Cuesta (~900 m of altitude) while the two others are in the Peripheric Depression (~600 m of altitude). Twenty six fish species were sampled in the river. The addition process was found to have a broader magnitude than the substitution process along the river. The sections at the Peripheric Depression presented high diversity indexes, low dominance values and uniform distribution among individuals of each species, these factors been related to an increase in habitat heterogeneity and reduction of environmental fluctuation. An oppositesituation was observed in the Cuesta sections, probablyrelated to their irregular topography and anthropicactivities. Such factors highly stresses the communityand brings about the low species diversity with a highdominance curve

Long-term effects of a rural landscape on the structure and trophic organization of a fish assemblage

Abstract Aim We investigated the long-term effects of a rural landscape on the structure and trophic organization of a fish assemblage. Methods We compared environmental data and data from fish assemblage structure and trophic organization sampled in a stream located in a rural area, within a time gap of 20 years. Results We observed only punctual changes in the environmental variables and fish structure, which may not be related to the rural landscape. In fish diet, insectivory remained predominant in all sample periods. However, when we analyzed the groups of hexapods consumed by the fish species, we found a substitution of Ephemeroptera and Trichoptera by Diptera over time. Conclusions Although the fish assemblage structure was not affected, the insectivore diet analysis showed that the stream stretch could be in an ongoing process of environmental quality loss, once the simplification in the macroinvertebrates assemblage structure over time is indicative of environmental degradation

Activity and habitat use of two species of stingrays (Myliobatiformes: Potamotrygonidae) in the upper Paraná River basin, Southeastern Brazil

Informações sobre o modo de vida das raias de água doce (Potamotrygonidae) sob condições naturais são escassas. Neste trabalho, estudamos o período de atividade e as formas de uso do habitat de duas espécies do gênero Potamotrygon na bacia do alto rio Paraná, no Sudeste do Brasil. Potamotrygon falkneri e P. motoro apresentaram comportamento muito semelhante, com nítida segregação espacial dos indivíduos em função do seu tamanho, da profundidade e do período do dia. Juvenis estiveram associados a praias arenosas e locais com profundidades abaixo de quatro metros ao longo de todo o dia. Raias de grande porte realizaram migrações batimétricas, alternando sua posição entre locais com profundidade superior a oito metros durante o dia e áreas mais rasas à noite. Indivíduos com tamanho intermediário ocuparam ambientes de transição, com maior heterogeneidade ambiental. Ambas as espécies apresentaram atividade, especialmente alimentar, predominantemente noturna. Os padrões comportamentais estudados parecem sofrer variações ontogenéticas e é provável que se alterem ao longo do ano, entre períodos de seca e cheia.The life history of freshwater stingrays (Potamotrygonidae) under natural conditions has been poorly documented. In this study, we investigated theperiod of activity and the habitat use of two species of the genus Potamotrygon in the upper Paraná River basin, Southeastern Brazil. Potamotrygon falkneri and P. motoro are similar to each other as far as the analyzed behavior is concerned. Individuals of both species segregate according to their size, and in function of the depth and period of the day. Younger individuals inhabit mostly sandy beaches and places that are no deeper than four meters throughout the whole day. Bigger stingrays realize bathymetric migrations, alternating their position between places deeper than eight meters during the day, and shallow areas at night. Individuals of intermediate size inhabit transition environments that have greater habitat diversity. Both species presented mostly nocturnal habits, especially regarding their feeding behavior. The behavioral patterns observed seem to go through ontogenetic variations and probably change throughout the year, between dry and wet seasons.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Food web structure in a tropical stream ecosystem

This study investigated the structure and properties of a tropical stream food web in a small spatial scale, characterizing its planktonic, epiphytic and benthic compartments. The study was carried out in the Potreirinho Creek, a second-order stream located in the south-east of Brazil. Some attributes of the three subwebs and of the conglomerate food web, composed by the trophic links of the three compartments plus the fish species, were determined. Among compartments, the food webs showed considerable variation in structure. The epiphytic food web was consistently more complex than the planktonic and benthic webs. The values of number of species, number of links and maximum food chain length were significantly higher in the epiphytic compartment than in the other two. Otherwise, the connectance was significantly lower in epiphyton. The significant differences of most food web parameters were determined by the increase in the number of trophic species, represented mainly by basal and intermediate species. High species richness, detritus-based system and high degree of omnivory characterized the stream food web studied. The aquatic macrophytes probably provide a substratum more stable and structurally complex than the sediment. We suggest that the greater species richness and trophic complexity in the epiphytic subweb might be due to the higher degree of habitat complexity supported by macrophyte substrate. Despite differences observed in the structure of the three subwebs, they are highly connected by trophic interactions, mainly by fishes. The high degree of fish omnivory associated with their movements at different spatial scales suggests that these animals have a significant role in the food web dynamic of Potreirinho Creek. This interface between macrophytes and the interconnections resultant from fish foraging, diluted the compartmentalization of the Potreirinho food web

Effect of the riparian vegetation removal on the trophic network of Neotropical stream fish assemblage

The study of the diet of fish is an important tool to assess different levels of environmental degradation, since the availability of food in the environment is a key factor for the fish occurrence. The removal of riparian vegetation usually degrades environmental quality, as this vegetation has an important role in providing energy to the ecosystem. This study investigates the effects of the removal of riparian vegetation on the fish assemblage trophic network. The study was carried out in two stretches of a southeastern Brazilian stream, one in a forest fragment and another in a pasture, during the wet and dry seasons of 2014. We analyzed the items consumed by each fish species using the frequency of occurrence and area of each item, which were combined to calculate the alimentary index, which was used to determine the food niche overlap of the fish and the specialization index of the trophic network. Aquatic Hexapoda, vegetal debris and organic matter dominated the trophic network of the two stretches. We detected higher values of food niche overlap in the forested stretch and more complex trophic networks in the pasture stretch. We found few seasonal variations in the items consumed and calculated indices in both stretches studied. The presence of grass on the banks in the pasture stretch and the importation of food resources from the upstream area may have provided a higher diversity of resources and consequently showed a more complex trophic network when compared to the forested stretch