Fluctuations of Testate Amoebae Populations (Rhizopoda) in Plankton from Different Environments on the Upper Paraná River Floodplain, Brazil

Autor: Fábio Amodêo Lansac-Tôha, Geziele Mucio Alves, Erica Mayumi Takahashi, Luiz Felipe Machado Velho
Rok vydání: 2008
Předmět:
Zdroj: International Review of Hydrobiology. 93:227-242
ISSN: 1522-2632
1434-2944
DOI: 10.1002/iroh.200711002
Popis: Fluctuations in temporal and spatial abundance are remarkable features of all animal populations. Regional synchrony of local population dynamics has been verified in several studies. This study investigated the existence of coherent patterns in temporal fluctuations of the principal testate amoebae population abundance in plankton from the upper Parana river floodplain in Brazil. Testate amoebae sampling was carried out every three months, from February 2000 to November 2002, and twice in 2003. Sampling occurred in 12 environments associated with three different rivers. Samples were obtained at the subsurface of the pelagic region, using a motorized pump and a 68 μm mesh plankton net. Ninety–three testate amoebae species from eight families were identified. The families Difflugiidae, Arcellidae, and Centropyxidae had the greatest number of species. Arcella conica, A. discoides, A. vulgaris, Centropyxis aculeata, C. ecornis, Difflugia gramen, D. pseudogramen and Cucurbitella dentata were the most abundant species, and they were chosen for spatial synchrony analysis. No coherent pattern of abundance fluctuation was found, in any of the floodplain environments studied. Nevertheless, when analyzing only the channels, spatial synchrony was observed to Centropyxis ecornis. Mantel tests showed that the synchrony level, as identified by Spearman and Pearson correlations, was not correlated to geographic distance between environments. We conclude that regional factors in the Upper Parana River floodplain are not the main determinants of the population dynamics of testate amoebae. The high floodplain heterogeneity seems determine a great relevance of local factors. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Databáze: OpenAIRE
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