The effect of connectivity on the relationship between local and regional species richness of testate amoebae (protozoa, rhizopoda) in floodplain lagoons of the Upper Paraná River, Brazil

2003 ◽  
Vol 24 ◽  
pp. S145-S151 ◽  
Author(s):  
L.M. Bini ◽  
L.F.M. Velho ◽  
F.A. Lansac-Tôha
2009 ◽  
Vol 69 (2 suppl) ◽  
pp. 707-716 ◽  
Author(s):  
EE. Souza Filho

The building of large dams in the Upper Paraná River basin altered the discharge regime at the Porto São José River section. The discharge regime has been altered since 1972, but the changes intensified after the Porto Primavera damming, in late 1998. Considering that discharge control affects the relationship between channel and floodplain, this work aimed to evaluate the intensity of the discharge control that resulted from the operation of the Porto Primavera Dam. To achieve this objective, statistical analyses were carried out based on the Porto São José Fluviometric Station historical series of river level readings and discharge, between 1964 and 2007. Results showed that the average discharge increased from 1964 to 1981 and diminished after river damming. The increase of average discharge rates was followed by an increase of the duration of higher discharges at different levels of geomorphologic and limnological importance, and the reduction of average discharge during the last observed period was followed by a disproportionate decrease in the duration of the abovementioned discharges. Moreover, it is clear that the relationship between fluviometric level and fluvial discharge changed, which implies that a certain river level reading represents a higher discharge than necessary before river damming.


2009 ◽  
Vol 69 (2 suppl) ◽  
pp. 727-734 ◽  
Author(s):  
H. Ortêncio-Filho ◽  
NR. Reis

The Upper Paraná River floodplain is inserted in a region of the Mata Atlântica biome, which is a critical area to preserve. Due to the scarcity of researches about the chiropterofauna in this region, the present study investigated species richness and abundance of bats in remnants from the stational semidecidual forest of the Upper Paraná River, southern Brazil. Samplings were taken every month, from January to December 2006, using 32 mist nets with 8.0 x 2.5 m, resulting in 640 m²/h and totaling a capture effort of 87,040 m²/h. In order to estimate the species richness, the following estimators were employed Chao1 and Jack2. During the study, a total of 563 individuals belonging to 17 species (Artibeus planirostris, Artibeus lituratus, Carollia perspicillata, Platyrrhinus lineatus, Sturnira lilium, Artibeus fimbriatus, Myotis nigricans, Desmodus rotundus, Artibeus obscurus, Noctilio albiventris, Phylostomus discolor, Phylostomus hastatus, Chrotopterus auritus, Lasiurus ega, Chiroderma villosum, Pygoderma bilabiatum and Lasiurus blossevillii) were captured. The estimated richness curves tended to stabilize, indicating that most of the species were sampled. Captured species represented 10% of the taxa recorded in Brazil and 28% in Paraná State, revealing the importance of this area for the diversity of bats. These findings indicate the need to determine actions aiming to restrict human activities in these forest fragments, in order to minimize anthropogenic impacts on the chiropterofauna.


2018 ◽  
Vol 30 (0) ◽  
Author(s):  
Kisay Lorena Adame ◽  
Barbara Dunck ◽  
Liliana Rodrigues

Abstract Aim: This study aimed to evaluate the influence of seasonal variation in the hydrological regime and of limnological variables on species richness of periphytic algae in lakes of the Upper Paraná River floodplain. Methods The study area is located in the last undammed stretch of the Paraná River in this floodplain, in which three lakes were sampled quarterly (May, August and November 2014, and February and May 2015) for one year. The periphytic material was obtained from petioles of the aquatic macrophyte Eichhornia azurea (Sw.) Kunth. Results We registered 149 taxa of periphytic algae, distributed in 9 classes. Algal richness changed as a function of the seasonal dynamics of the Paraná River’s hydrological regime. Water level fluctuations directly influenced periphytic algae species. During periods of high water level, species richness increased. Limnological variables showed a close relationship with the hydrological regime, and the dissolved nutrients and turbidity were the abiotic factors that most influenced the algal community. The following species were present in all lakes: Fragilaria capucina Desmazières, Gomphonema gracile Ehrenberg and Navicula cryptotenella Lange-Bertalot (Bacillariophyceae) and two species of the genus Oedogonium (Oedogoniophyceae). Conclusions The hydrological regime of the Paraná River played an important role in structuring communities of periphytic algae. Seasonal variation in hydrological regime and in limnological variables together influenced the species richness of these organisms in these floodplain lakes.


2017 ◽  
Vol 29 (0) ◽  
Author(s):  
Andressa Bichoff ◽  
Nicolli Cristina Osório ◽  
Daiane Trevisan Ruwer ◽  
Kisay Lorena Adame Montoya ◽  
Bárbara Dunck ◽  
...  

Abstract In impacted floodplains, small tributaries have an essential role in the maintenance of ecosystem biodiversity. Aim: We aimed to characterise the periphytic diatom community (Bacillariophyta) in a protected area at the Upper Paraná River floodplain considering the importance of tributaries as a source of propagules. The purpose of this study was to understand the influence of the tributaries in the periphytic diatom community (Bacillariophyta) in a protected area at the Upper Paraná River floodplain. We expect that species present in the main river channel (mainly in the last stretch) would be a subset of the community present in the tributaries. Methods The study area is located in the last non-dammed stretch of the Paraná River in this floodplain, with the contribution of several tributaries. Sampling was performed in 2014 in two tributaries and three sites at the Paraná River main channel, and the periphytic material was obtained from petioles of the aquatic macrophyte Eichhornia azurea (Sw.) Kunth. Results We identified 115 diatom taxa. Higher values of species richness were registered in the tributaries, and higher densities in the tributaries and at sampling sites under the direct influence of the tributaries. We also observed a higher similarity between the tributaries, which are located in the preserved side of the floodplain. The results of beta diversity showed that closer sites had lower values, and that the species turnover was the component more important in this floodplain. Conclusion In this way, these results reinforce the importance of tributaries mainly on the algae establishment and development reflected in the density of species. It demonstrates that sites in preserved area present a higher species richness and can serve as a pool of propagules for downstream environments.


2009 ◽  
Vol 69 (2 suppl) ◽  
pp. 501-516 ◽  
Author(s):  
LC. Rodrigues ◽  
S. Train ◽  
VM. Bovo-Scomparin ◽  
S. Jati ◽  
CCJ. Borsalli ◽  
...  

The interannual variation of phytoplankton communities in the three main rivers of the Upper Paraná River floodplain is evaluated in relation to changes in the hydrosedimentological regime. These changes are a result of climatic variability and the formation of Porto Primavera Reservoir, located at the upper Paraná River. Phytoplankton species richness and density were investigated in rivers during a prior period (1993-1994) and eight years after reservoir impoundment (2000-2007). Multiple analyses were conducted to test the differences between these time periods in order to find predictor variables for phytoplankton attributes. A total of 454 phytoplanktonic taxa were found. The regression analysis revealed significant differences between periods. In the years following construction of the Porto Primavera dam, species richness was lower in the Paraná River and density was higher in the three rivers. In general, the algal density decreased from 2005 to 2007. Diatoms and cyanobacteria contributed significantly to the total density during the period from March 1993 to February 1994. The years 2000-2007 presented the lowest diatom contribution to species richness and the highest cyanobacteria contribution. From 2000 on, cryptomonads and cyanobacteria dominated. The interannual variability of phytoplankton was probably influenced by changes in hydrosedimentological regime due to climatic variations (La Niña and El Niño - Southern Oscillation events - ENSO) and the operational procedures associated with an upstream reservoirs. Studies on climatic variability and its effects on hydrosedimentological regimes of the Paraná, Baía and Ivinhema rivers and the biota therein are necessary to obtain subsidies for management, including decisions related to the operation of dams upstream and downstream of the study area, with the purpose of minimizing risks to the Environmental Protection Area.


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