The upper Paraná river floodplain is a strategic area for the Brazilian biological and environmental patrimony and contains several conservation units. We aimed to record the occurrence and the geographic distribution of microalgae in this floodplain during 30 years of research carried out by the Center for Research in Limnology, Ichthyology and Aquaculture - State University of Maringá. We consulted 80 publications (national and international journals and books published from 1986 to 2016). We considered only published works that referenced algae at the generic and infrageneric levels. The results indicated 938 species of algae (562 periphytic, 482 planktonic), which 103 co-occur in the two habitats. Cosmarium was the richest genera for periphyton and Traquelomonas for phytoplankton. This study increased the knowledge of microalgae biodiversity in Brazil and provided data for future ecological and biogeographic studies.
Aim:We analyzed the temporal distribution (dry and rainy periods) of phytoplankton functional groups (biovolume) from lakes connected to dammed (S1 -Paraná River) and non-dammed rivers (S2 -Baia River and S3 -Ivinhema River) in the upper Paraná River floodplain, Brazil. We also determined the drivers of the phytoplankton community assemblage. Methods: Phytoplankton and environmental variables samplings were performed quarterly in dry (2000 and 2001) and rainy (2010 and 2011) periods. We classified the phytoplankton species into seven morphological based functional groups (MBFG). We used analysis of variance to test differences in total phytoplankton biovolume and MBFGs biovolume between lakes and climatic periods. We also used redundancy analysis to determine the MBFGs-environment relation. Results: The lake related to the dammed river (S1) presented the lowest species richness. The total phytoplankton biovolume presented differences among the lakes, but we did not register temporal differences associated with water level variation. The lake related to the non-dammed and semi-lentic river (S2) presented the highest biovolume, while S1 (related to the dammed river) and S3 (related to the non-dammed river) exhibited the lowest ones. Filamentous organisms (MBFG III) were associated with poor nutrient conditions and diatoms (MBFG VI) were favored in high water mixing sites. The flagellate groups MBFG II and MBFG V were related to deeper water and lower column mixing conditions, respectively. Conclusions: Our results suggest that phytoplankton species with different functional traits drive the primary productivity in the dry and rainy periods. Hence, we highlight the importance of maintaining high functional 2 Pineda, A. et al.
Aim: To evaluate the influence of upstream reservoirs on the temporal and spatial variation of the phytoplankton community in the Paraná River channel and the importance of its main tributaries in reducing the oligotrophication process along this stretch of the river. Materials and Methods Sampling of phytoplankton and physical and chemical variables was performed quarterly between August 2013 and May 2015, in the Paraná River main channel and in the mouth of the main tributaries, at the stretch located between downstream Porto Primavera reservoir and the backwaters of Itaipu reservoir. To summarize the variation of phytoplankton density in relation to the main physical and chemical variables, we performed a Redundancy Analysis (RDA). Results A total of 214 taxa were identified throughout the study. We registered low values of phytoplankton species richness and abundance, which showed no patterns of temporal and spatial distribution, both for the Paraná River and the tributaries. However, RDA results showed spatial segregation among samples from the Paraná River main channel, such that the stretch located closer to the dam was associated with higher values of water transparency and Cyanobacteria density, exported by upstream reservoirs, whereas the middle and lower stretches were associated with higher phytoplankton complexity and higher nutrient concentration and turbidity. Conclusion Through the analysis of the phytoplankton community we could verify a reduction in the effects of oligotrophication along the longitudinal axis of the Paraná River and the important role of the tributaries in diminishing this effect.
Protection areas favor diversity as they decrease the impact of anthropic disturbance on biological communities. Testing its effects on diverse biological communities is a pivotal step to understand how different trophic levels react to such management and conservation strategies. Here, we used data collected from 1993 to 2018 from a subtropical floodplain to evaluate the effect of the installation of a protection zone on the taxonomic and functional diversity of the phytoplankton community. We showed that the installation of the park had a positive effect on the aquatic community, mainly related to the decrease of cyanobacteria dominance and to the increase of phytoplankton functional groups. However, our results also suggested that dynamics occurring in a scale beyond the park seemed to influence key factors for the phytoplankton community, such as transparency and nutrient concentrations. Thus, although we showed that a compensatory measure had a positive effect on biodiversity, we believe that the establishment of protection zones must also consider and integrate the management of the river basin where the areas to be protected are located.
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