ABSTRACT
Abstract: Knowledge of biodiversity in oligotrophic aquatic ecosystems is fundamental to plan conservation strategies for protected areas. This study assessed the diatom diversity from an urban reservoir with oligotrophic conditions. The Piraquara I reservoir is located in an Environmental Protection Area and is responsible for the public supply of Curitiba city and the metropolitan region. Samples were collected seasonally between October 2007 and August 2008. Periphytic samples were obtained by removing the biofilm attached to Polygonum hydropiperoides stems and to glass slides. The taxonomic study resulted in the identification of 87 diatom taxa. The most representative genera regarding the species richness were Pinnularia (15 species) and Eunotia (14 species). Five species were registered for the first time in Brazil and seven in the State of Paraná. Taxonomic and ecological comments of the species registered are provided.
Resumo: O conhecimento da biodiversidade em ecossistemas aquáticos oligotróficos é fundamental para planejar estratégias de conservação de áreas protegidas. Este estudo teve como objetivo conhecer a diversidade de diatomáceas em um reservatório urbano com condições oligotróficas. O reservatório do Piraquara I está inserido em uma Área de Proteção Ambiental em região de manancial e é responsável pelo abastecimento público de Curitiba e região metropolitana. Foram realizadas coletas estacionais entre os meses de outubro de 2007 e agosto de 2008. As amostras perifíticas foram obtidas pela remoção do biofilme aderido a caules de Polygonum hydropiperoides e de lâminas de vidro. O estudo taxonômico resultou na identificação de 87 táxons. Os gêneros mais representativos, considerando a riqueza de espécies, foram Pinnularia (15 espécies) e Eunotia (14 espécies). Cinco espécies de diatomáceas foram registradas pela primeira vez no Brasil e sete no estado do Paraná. Comentários taxonômicos e ecológicos também são apresentados para as espécies encontradas.
ABSTRACT
Stomach contents of Simulium perflavum Roubaud larvae were analyzed and compared with plankton and periphyton collected in five streams, in Central Amazonia (Manaus and Presidente Figueiredo counties), in Sep./Oct.1996 (dry season) and Feb./Mar. 1997 (rainy season). A total of 1,400 last-instar larvae were dissected; the stomach contents were analyzed using different methods: fresh and after oxidation. A total of 87 taxa (algae, diatoms and rotifers) were found in the stomach contents. In each stream, qualitative samples of plankton and periphyton were collected; these were mounted between slides and cover slips. A total of 94 taxa of plankton and 54 taxa of periphyton were collected. One species of Rotifera was present in the stomach contents, plankton and periphyton. Cluster analysis based on species composition of the organisms present in the stomach contents grouped the streams into two major groups, each belonging to a different drainage area. Correlations based on presence/absence of species of microalgae in the stomach contents, plankton and periphyton indicated significant associations (p<0.05) between stomach contents and plankton and between plankton and periphyton (z test); the Sorensen coefficient and cluster analysis corroborate the same associations