scholarly journals Tributaries as richness source for Oligochaeta assemblage (Annelida) of Neotropical dammed river

2014 ◽  
Vol 74 (4) ◽  
pp. 861-869 ◽  
Author(s):  
FH Ragonha ◽  
DK Petsch ◽  
GHZ Alves ◽  
HS Santana ◽  
TS Michelan ◽  
...  
Keyword(s):  
Abundant Species ◽  
Benthic Invertebrate ◽  
Main Channel ◽  
Paraná River ◽  
Good Tool ◽  
Parana River ◽  
Main River ◽  
The Difference ◽  
Invertebrate Assemblage ◽  
Dammed River

Tributaries may serve as richness source for the river main channel and the zoobenthos community is a good tool to verify this kind of pattern. In this study, we aimed to characterize the benthic invertebrate assemblage in three tributaries associated to the Paraná River main channel, focusing in Oligochaeta community. We hypothesized that (i) in tributaries, Oligochaeta are richer than the main river (Paraná River) and (ii) dammed tributary (Paranapanema River) is poorly diverse than the others. Samples were conducted in Paranapanema, Baía and Ivinhema tributaries using a modified Petersen grab along three transects (samples conducted inside the tributary, in the mouth of each tributary and inside Paraná River). To analyze (i) the difference between the richness and density among the tributaries and the Paraná River and (ii) effect of each tributary transect on the Oligochaeta richness we used a nonparametric Kruskal-Wallis test. Changes in environmental variables and in richness and composition of Oligochaeta were summarized by Canonic Correspondence Analysis. It was registered 21 different benthic invertebrates taxa, being Oligochaeta assemblage with the highest density. Within Oligochaeta, Narapa bonettoi was the most abundant species, followed by Haplotaxis aedochaeta and Paranadrilus descolei. In our results we refused both hypotheses, because we did not found significant differences for richness and density between the tributaries and the main river, and also no difference between the three transects of each tributary were found. However, the tributaries less influenced by damming, especially the Baía recorded high richness. This corroborates their importance to diversity in the floodplain and the species of Oligochaeta reflect the peculiar characteristics of habitats within each tributaries.

scholarly journals Orthohantavirus infection in two rodent species that inhabit wetlands in the central-east region of Argentina

2022 ◽  
Author(s):  
Malena Maroli ◽  
Carla M. Bellomo ◽  
Rocío M. Coelho ◽  
Valeria P. Martinez ◽  
Carlos I. Piña ◽  
...  
Keyword(s):  
Abundant Species ◽  
Individual Characteristics ◽  
Paraná River ◽  
River Delta ◽  
Adult Males ◽  
Parana River ◽  
East Region ◽  
Rodent Community ◽  
The Individual ◽  
High Degree

Hantavirus pulmonary syndrome (HPS) is an emerging infectious disease caused by orthohantaviruses associated to rodents of the Cricetidae family, Sigmodontinae subfamily, in the American continent. Previous research carried out in central-east region of Argentina, recorded potential orthohantavirus host rodents in diverse environments, but infected rodents were particularly present on Paraná wetlands islands. The aims of this research were (1) to determine the orthohantavirus host in the rodent community focused on islands of Paraná River Delta, an endemic zone of HPS, (2) to identify temporal and spatial factors associated with orthohantavirus prevalence variations, (3) to compare the individual characteristics of seropositive and seronegative rodents and, (4) to explore the association between orthohantavirus seroprevalence and rodent community characteristics in the Paraná River Delta, central-east region of Argentina. Capture of small rodents was done between August 2014 and May 2018 on seven islands located in central-east region of Argentina. In this HPS endemic zone, 14.9% of Oligoryzomys flavescens and 1.5% of Oxymycterus rufus of the sampled rodents had antibodies against orthohantavirus. The individuals that were more likely to become seropositive were the reproductively active adult males. Even though O. flavescens inhabit all islands, the seropositive individuals were only present in two of these, suggesting spatial heterogeneity in the viral distribution. We found that two months later of periods with low temperature, seroprevalence increased probably due to a higher proportion of adults in the population. Additionally, higher seroprevalence was associated with greater diversity of the rodent assemblage. This association could support the idea that a rescue effect or amplification of the prevalence of orthohantavirus would be taking place by means of secondary host as O. rufus, a novelty for this species and for the region. This finding may be significant if one takes into account that O. rufus was the second most abundant species in the area of islands studied and is one of the most abundant species on the islands and riparian sectors of the study zone. In conclusion, the relative risk of HPS could be high on wetlands of Paraná River Delta in the central-east region of Argentina where several favourable factors for the transmission of orthohantavirus are combined, such as the presence of several host species, two of them numerically dominant, high percentages of infection and a high degree of occupational exposure of the human population due to rural activities, the most frequently associated nationwide with HPS.

scholarly journals Species inventory of aquatic macrophytes in the last undammed stretch of the Upper Paraná River, Brazil

2017 ◽  
Vol 29 (0) ◽  
Author(s):  
Douglas Costa Souza ◽  
Eduardo Ribeiro Cunha ◽  
Raytha de Assis Murillo ◽  
Márcio José Silveira ◽  
Mikaela Marques Pulzatto ◽  
...  
Keyword(s):  
Hydrilla Verticillata ◽  
Main Channel ◽  
Paraná River ◽  
Panicum Maximum ◽  
Species Accumulation Curves ◽  
Parana River ◽  
Frequent Species ◽  
Eichhornia Azurea ◽  
Macrophyte Species ◽  
Upper Paraná River

Abstract The last undammed stretch of the Upper Paraná River in the Brazilian territory is, to date, not completely inventoried, which rises concerns given the rapid rates of species extinctions. Aim Here, we provide an inventory of macrophyte taxa recorded in the last undammed 230 km stretch of the Upper Paraná River. Methods We inventoried macrophyte taxa in 27 sampling stations including lakes, the main channel of the river, and the tributary confluences in November 2013 and in May and November 2014. Macrophyte were sampled in littoral zones. We explored taxonomic and life form aspects of the recorded species. We used species accumulation curves and ordination techniques to summarize the variation in richness and composition of macrophyte species. Results We recorded 71 macrophyte taxa in 35 families. Most species were emergent, amphibian, free-floating, and rooted submerged. At the main channel of the Upper Paraná River, Eichhornia azurea, E. crassipes, and Paspalum repens represented the most frequent species. The most frequent species in the tributary confluences were Ludwigia sp., E. azurea, and Polygonum ferrugineum, while in lakes, Ludwigia sp., Oxycaryum cubense, and E. azurea were the most representative taxa. In regard to macrophyte composition, the invasive Hydrilla verticillata mostly influenced sites in the Upper Paraná River, in the ordination space, while floodplain lakes were mostly characterized by the presence of species such as Scleria melaleuca, Panicum maximum, and Thelypteris sp., among others. Conclusions Our study indicates that the last undammed stretch of the Upper Paraná River contains a large number of macrophyte species, suggesting that this stretch is an important area for the conservation of macrophyte species. In addition, the occurrence of invasive species (e.g., Hydrilla verticillata) within the investigated stretch deserves attention in terms of potential impacts for which management action may be necessary.

scholarly journals Rivers affect the biovolume and functional traits of phytoplankton in floodplain lakes

2017 ◽  
Vol 29 (0) ◽  
Author(s):  
Alfonso Pineda ◽  
Geovani Arnhold Moresco ◽  
Aline Caroline Magro de Paula ◽  
Luciane Maria Nogueira ◽  
Patricia Iatskiu ◽  
...  
Keyword(s):  
Functional Groups ◽  
Functional Traits ◽  
Primary Productivity ◽  
Temporal Distribution ◽  
Paraná River ◽  
Floodplain Lakes ◽  
Phytoplankton Species ◽  
Parana River ◽  
Total Phytoplankton ◽  
Dammed River

Abstract 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 diversity in lakes to ensure primary productivity. Therefore, we stress the importance of protecting the natural environment such as floodplain lakes because of its contribution to the regional biodiversity and the flow of energy.

scholarly journals Importance of dam-free stretches for fish reproduction: the last remnant in the Upper Paraná River

2017 ◽  
Vol 29 (0) ◽  
Author(s):  
Jislaine Cristina Silva ◽  
Rafael Rogério Rosa ◽  
Eliana Maria Galdioli ◽  
Claudemir Martins Soares ◽  
Wladimir Marques Domingues ◽  
...  
Keyword(s):  
Invasive Species ◽  
Fish Fauna ◽  
Taxonomic Composition ◽  
Main Channel ◽  
Paraná River ◽  
Long Distance ◽  
Prochilodus Lineatus ◽  
Parana River ◽  
Composition And Structure ◽  
Eggs And Larvae

Abstract Aim: This study uses the abundance of fish eggs and larvae to evaluate the importance of the main channel of the Paraná River and the adjacent areas of the floodplain, in the last dam-free stretch in the Brazilian territory, for the spawning and development of fish of different reproductive guilds, in order to obtain subsidies to assist in the management and conservation policies of this area, focusing on the maintenance of dam-free areas. Methods Data were taken quarterly from August 2013 to May 2015, in 25 sites, grouped into three biotopes: main channel, tributaries and lagoons. Possible spatial variations in fish spawning and development as well as composition and structure of larvae were evaluated. Results Higher densities of eggs were found in tributaries (Paracaí and Amambai rivers) and greater densities of larvae were observed in lagoons (Saraiva). Significant differences in composition and structure of larvae were detected only between sampling stations. As for taxonomic composition, 29 taxa were recorded, mostly non-migratory. However, long-distance migratory were also widely distributed, such as Brycon orbignyanus, Pseudoplatystoma corruscans, Prochilodus lineatus, Piaractus mesopotamicus and Rhaphiodon vulpinus, as well as invasive species Platanichthys platana and Hemiodus orthonops. In turn, Salminus brasiliensis presented low occurrence. Conclusions This study evidenced that different species spawn in the region, mainly in tributaries, and their eggs and larvae are transported to the main channel of the Paraná River and adjacent lagoons, to complete their early development. The capture of larvae of important migratory species suggests that this environment still exhibits suitable conditions for their reproduction, mainly due to the presence of dam-free tributaries. Also, they emphasize the importance of the integrity of these environments for the maintenance of the regional fish fauna, and it is extremely important the monitoring of reproduction of the most endangered species, as well as of invasive species.

scholarly journals The ichthyofauna of drifting macrophyte mats in the Ivinhema River, upper Paraná River basin, Brazil

2011 ◽  
Vol 9 (2) ◽  
pp. 403-409 ◽  
Author(s):  
Cíntia Karen Bulla ◽  
Luiz Carlos Gomes ◽  
Leandro Esteban Miranda ◽  
Angelo Antonio Agostinho
Keyword(s):  
Fish Assemblages ◽  
Mesh Size ◽  
Paraná River ◽  
Parana River ◽  
Main River ◽  
Main River Channel ◽  
Dispersal Vectors ◽  
Upper Paraná River ◽  
Number Of Individuals

We describe the fish assemblages associated with drifting macrophyte mats and consider their possible role as dispersal vectors in the Ivinhema River, a major tributary of the upper Paraná River, Brazil. Fish associated with drifting mats were sampled in the main river channel during January and March 2005, when the wind and/or the increased water level were sufficient to transport macrophyte stands. Fish in the drifting mats were sampled with a floating sieve (4 m long x 2 m wide x 0.6 m high, and 2 mm mesh size). In the laboratory, larvae, juvenile, and adult fish were counted and identified to the lowest possible taxonomic level. In four drifting macrophyte mats we captured 218 individuals belonging to at least 28 species, 17 families, and 6 orders. Aphyocharax dentatus, Serrasalmus spp., and Trachelyopterus galeatus were the most abundant taxa associated with the mats, but species richness ranged from 6 to 24 species per mat. In addition, 85% of the total number of individuals caught was larvae and juveniles. Although preliminary and based on limited samples, this study of drifting macrophyte mats was the first one in the last unregulated stretch of the Paraná River remaining inside Brazilian territory, and alerts us to the potential role of macrophytes mats as dispersers of fish species in the region.

scholarly journals Phytoplankton community in the last undammed stretch of the Paraná River: considerations on the distance from the dam

2017 ◽  
Vol 29 (0) ◽  
Author(s):  
Susicley Jati ◽  
Jascieli Carla Bortolini ◽  
Geovani Arnhold Moresco ◽  
Aline Caroline Magro de Paula ◽  
Luzia Cleide Rodrigues ◽  
...  
Keyword(s):  
Phytoplankton Community ◽  
Longitudinal Axis ◽  
Main Channel ◽  
Paraná River ◽  
Temporal And Spatial Distribution ◽  
Parana River ◽  
Physical And Chemical Variables ◽  
Temporal And Spatial ◽  
Species Richness And Abundance ◽  
Physical And Chemical

Abstract 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.

scholarly journals Selection of an experimental fish ladder located at the dam of the Itaipu Binacional, Paraná River, Brazil

2004 ◽  
Vol 47 (4) ◽  
pp. 579-586 ◽  
Author(s):  
Domingo Rodriguez Fernandez ◽  
Angelo Antônio Agostinho ◽  
Luis Mauricio Bini
Keyword(s):  
Negative Selection ◽  
Abundant Species ◽  
Hydraulic Model ◽  
Paraná River ◽  
Parana River ◽  
Experimental Fish ◽  
Fish Ladder ◽  
Selection Of Species ◽  
Selection Of

The specific selection of a weir and orifice type experimental fish ladder in the dam of the Itaipu Reservoir (Paraná River) was evaluated by samplings in the river downstream and at two points along the ladder (at heights of 10 m and 27 m) during 28 months. Among the 65 species recorded in the river (immediate downstream of the dam), 27 were captured on the ladder. The species that showed highest density on the ladder, the majority migratory, were moderately, or only slightly, abundant downstream. Among the most abundant species downstream, only one, non-migratory, was recorded in the ladder. The structure presented a negative selection in relation to large migratory pimelodids that might be overcome by enlarging the scale of its design. The sampling demonstrated a moderate selection of species along the ladder and its hydraulic model proved satisfactory regarding the attraction and efficient ascent of the fishes.

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