Evaluation of the relative influences of environmental and spatial processes in structuring aquatic metacommunities is an essential first step for understanding how these factors govern species distributions and affect spatial and temporal variability in community structure. Such variability has many causes and consequences at different scales. In the case of phytoplankton metacommunities, both species sorting and mass effect processes are likely to be important in structuring the patterns of biomass distribution on large spatial scales. We investigated the influences of environmental and spatial components on the phytoplankton community on a large spatial scale, consisting of a reservoirs‐river‐floodplain lakes gradient in a Neotropical region. Using partial redundancy analysis, we partitioned the relative role of environmental (environmental filters) and spatial (asymmetric eigenvector maps) processes structuring phytoplankton biomass. A clear difference of the limnological conditions was observed between the reservoirs and river–floodplain lakes system. High species richness and higher mean values of phytoplankton biomass were recorded in the floodplain lakes. Variation partitioning demonstrated the importance of both environmental and spatial process in phytoplankton biomass structuring. However, the relative importance of these processes may vary over time. Our results suggest that from a metacommunity perspective, the phytoplankton biomass of upstream reservoirs and a downstream river–floodplain lakes system is determined by environmental conditions (species sorting process), mainly in the floodplain lakes; and by high dispersion rates favoured by the connectivity and unidirectional flow (mass effect process), mainly between the reservoirs and the river.

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AIM: Models of phytoplankton functional classification based on functional (FGs) and morphological (MBFGs) traits can be an important tool in aquatic monitoring. In this long-term study on phytoplankton, the goal was to use these two approaches to explain the changes in this community in an active channel of the Upper Paraná River floodplain, depending on the environmental conditions imposed by the hydrosedimentological regime. METHODS: Samples were taken between 2000 and 2013. RESULTS: 196 taxa were identified. Bacillariophyceae and Cyanobacteria showed higher contribution to biovolume. Were recorded 11 FGs (A, C, E, H1, J, Lo, M, MP, N, P and X1). The FGs C, Lo, M, MP, P and X1 were common to both periods. Already the FGs A, E, H1 and J occurred only in limnophase, while the FG N occurred only in potamophase. Were recorded seven MBFGs (I, II, III, IV, V, VI e VII). All seven MBFGs occurred in both hydrological periods, however the MBFGs III, VI and VII contributed with high biovolume values mainly in the limnophase. The FG P and MBFG VI were indicator of eutrophic status, while the FG M and MBFG VII were indicators of mesotrophic status. Only FGs reflected the environmental variability. CONCLUSION: The classification of phytoplankton in FGs and MBFGs represented an important tool for understanding of the behavior and dynamics of the species in relation to environmental conditions. However, the FGs appear to be more related to environmental variation this lotic channel than MBFGs. Probably this is related to the refinement of this classification, which reflected the changes in the community, in long-term scale, influenced by local and regional characteristics imposed by the hydrosedimentological regime of the Paraná River.

-(Closterium Nitzsch ex Ralfs (Desmidiaceae) in an urban artificial lake, Paraná State, Brazil). An investigation of the genera Closterium from an artificial lake of Cascavel city, Paraná, Brazil was undertaken. The samples were collected from January/2002 to November/2003, in the lake littoral zone. Seventeen taxa of the genera Closterium were identified, where 13 of them were typical and four of them non-typical varieties. C. cynthia De Notaris var. cynthia, represented 25% of total samples, followed by C. moniliferum (Bory) Ehrenberg ex Ralfs var. moniliferum (17%). Taxa

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-(The genus Cosmarium Corda ex Ralfs (Desmidiaceae) in the Itaipu Reservoir, PR, Brazil). The study aimed to survey the flora of the Cosmarium genera on a tributary of Itaipu dam in western Paraná State. Samples were collected monthly from the biological community in five sampling stations in the limnetic region of the São Francisco Falso river tributary, Santa Helena, Paraná, between July 2003 and June 2004. Were used as criteria of occurrence of taxa in the samples constancies accidental, incidental and constant. The inventory resulted in the identification, description and illustration of 23 taxa, including 10 at the specific,13 infraspecific level, and of these, seven varieties typical of their species and six varieties not typical of their species, and taxonomic two forms. The vast majority of taxa surveyed (69.5%) had an accidental constancy, and the remaining species (30.5%) represented by the constant accessory. There wasn't occurrence of constant taxa.

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