Structure of planktonic ciliates community (Protist, Ciliophora) from an urban lake of southern Brazil - doi: 10.4025/actascibiolsci.v35i4.18579

This study examined temporal and spatial (vertical) variations of composition, richness and abundance of the planktonic ciliates community in an urban and eutrophic lake, as well as identified the limnological factors involved in determining the patterns observed. To this end, samples of ciliates and measures of limnological variables were taken at different depths and hydrological periods. 35 ciliate species were identified, among which 14 species occurred in all periods and strata, being Prostomatida the most specious, followed by Gymnostomatida, Oligotrichida, Peritrichida, and Scuticociliatida. The patterns found for composition, abundance and species richness evidenced a vertical and temporal variation of these attributes. However, in general the composition and species richness have varied more along the vertical gradient than between periods, whereas for the abundance, only temporal differences could be detected. Results observed herein indicated that benthic species seem to be mainly influenced by the amount of organic matter, phosphorus and ammonia, while planktonic ones, abundant at the surface, were mainly associated with higher dissolved oxygen concentrations. In this way, seasonal and vertical variations of limnological characteristics were decisive for the patterns of occurrence and abundance of ciliate species.

Flagellate protist abundance in phytotelmata of Aechmea distichantha Lem. (Bromeliaceae) in the upper Paraná river basin - doi: 10.4025/actascibiolsci.v35i4.17134

In some Bromeliaceae species the leaf sheaths form a tank or phytotelma, accumulating water and organic detritus, conditions that allow the establishment of different communities. Thus, this study evaluated the relationship between diameter and volume of water in the tank of the bromeliad Aechmea distichantha Lem. and density of flagellates found in the phytotelmata, as well as the influence of the hydrological periods and proximity of sampled strata on the phytotelma patterns of abundance distribution. Samplings were conducted in two hydrological periods in 2010. In each sampling, four plants were collected from three different strata, classified according to the distance from the river level. A one-way ANOVA identified significant differences in flagellate density between hydrological periods. The influence of the water volume in the phytotelmata on the flagellate density was evidenced by regression analyses, as well as the lack of relationship between the density and perimeter of the tank. Moreover, the distance of the strata from the river level did not influence the pattern of flagellate abundance. Thus, our results suggested that the hydrological period and the volume of water in the tanks of Aechmea distichantha are determinant on the abundance of heterotrophic flagellate in the phytotelmata.

Advances in studies on testate amoebae (Arcellinida and Euglyphida): a scientometric approach - doi: 10.4025/actascibiolsci.v35i4.18184

Testate amoebae have a great potential for use in scientific researches due to their ecological characteristics such as abundance, wealth, and generation time. In this way, this study aimed to present a scientometric analysis to describe the evolution of the different advances in researches on testate amoebae and identify a temporal pattern in this evolution. The literature review was based on papers indexed by Thomson Reuters (www.isiwebofknowledge.com) and SciVerse Scopus (www.scopus.com). In total 562 papers were examined. Results showed a pattern of evolution in scientific studies, most with ecological approach with descriptive and predictive designs. At the global level, researches on testate amoebae progressed in both the number of articles published as well as in the areas studied, especially in Europe and North America. The low number of experimental studies and review articles can characterize the lack of more knowledge to be acquired, both from particular observations (descriptive studies) as well as the observations noted sufficiently predictive of work. In Brazil, studies with testate amoebae are still developing, concentrated in only some regions, but the increased number of studies in recent years allows the prediction of the same overall patterns of advance for Brazilian researches. Thus, we conclude that these organisms are being increasingly used as a tool resp

Passive zooplankton community in different environments of a neotropical floodplain - doi: 10.4025/actascibiolsci.v34i4.11161

Zooplankton is able to respond promptly to environmental changes, producing resting forms in order to maintain populations when the conditions become unfavorable. The hatchling of the resting eggs was assessed in environments from the upper Paraná river floodplain, during the limnophase of 2008. We predicted that a higher production of these eggs and individuals hatchling are observed at isolated lakes, during dried period. Sediment samples were obtained with a corer sampler. The resting eggs were sorted and kept in filtered water from the same environment, in the laboratory. We recorded the occurrence of 378 resting eggs, of which 122 individuals hatched (70 cladocerans and 52 rotifers). The highest number of hatchlings was verified for the isolated lakes (84 individuals), as well the shorter time for hatchling (2 days). The hatchlings occurred mainly in September, when we registered the lowest hydrologic level of Paraná river (2.40 m). Grimaldina brazzai presented the longest time for hatchling, 44 days; and Brachionus dolabratus and B. falcatus, the shortest time, 2 days. This result suggests that the longer residence time of the water, which did not allow a renewal of food resources and limnological conditions of the environment, caused a higher stress in the zooplankton.

Spatial variations in the zooplankton community from the Corumbá Reservoir, Goiás State, in distinct hydrological periods - DOI: 10.4025/actascibiolsci.v31i3.4132 / Spatial variations in the zooplankton community from the Corumbá Reservoir, Goiás State, in distinct hydrological periods - DOI: 10.4025/actascibiolsci.v31i3.4132

This study evaluated the spatial variations in species richness and abundance of zooplankton over a hydrological cycle, and also verified the influence of physical and chemical water variables and chlorophyll-a concentrations on the abundance of these organisms. The tested hypothesis was that the zooplankton community presents higher species richness in lotic environments and higher abundance in lentic ones. One hundred forty species were identified, distributed among rotifers (88), testate amoebae (35), cladocerans (13) and copepods (4). Higher values of species richness and abundance were observed during the dry period. During both hydrological periods, the copepods presented high abundance values, due to the contribution of young stages, followed by rotifers, cladocerans and testate amoebae. In general, testate amoebae presented high values of species richness and abundance in lotic sampling stations, whereas the other zooplankton groups (rotifers, cladocerans and copepods) presented higher abundances in lentic environments and higher species richness in lotic ones. The Pearson correlation analysis evidenced the importance of physical and chemical water variables and food resource availability influencing the variation of organisms abundance.

This study evaluated the spatial variations in species richness and abundance of zooplankton over a hydrological cycle, and also verified the influence of physical and chemical water variables and chlorophyll- concentrations on the abundance of these organisms. The tested hypothesis was that the zooplankton community presents higher species richness in lotic environments and higher abundance in lentic ones. One hundred forty species were identified, distributed among rotifers (88), testate amoebae (35), cladocerans (13) and copepods (4). Higher values of species richness and abundance were observed during the dry period. During both hydrological periods, the copepods presented high abundance values, due to the contribution of young stages, followed by rotifers, cladocerans and testate amoebae. In general, testate amoebae presented high values of species richness and abundance in lotic sampling stations, whereas the other zooplankton groups (rotifers, cladocerans and copepods) presented higher abundances in lentic environments and higher species richness in lotic ones. The Pearson correlation analysis evidenced the importance of physical and chemical water variables and food resource availability influencing the variation of organisms abundance.

New occurrences of Lecane in plankton in different environments of the upper Paraná river floodplain - DOI: 10.4025/actascibiolsci.v30i3.3636 / Novas ocorrências de Lecane no plâncton de distintos ambientes da planície de inundação do alto rio Paraná (Brasil) - DOI: 10.4025/actascibiolsci.v30i2.3636

The upper Paraná river floodplain possesses a great diversity of rotifers, with 288 planktonic taxa recorded. Surveys performed in this ecosystem since 1992 have shown that Lecanidae is the most abundant family, with 45 registered taxa. The main goal of the present study was to investigate the occurrence of this family in environments that have not yet been studied. Seven new occurrences of Lecane were recorded in plankton samples: L. bifurca, L. rhytida, L. subtilis, L. crepida, L. bulla styrax, L. obtusa, and L. thienemanne. Although the described taxa were found in plankton, this family is characterized by being typically non-planktonic. As such, exclusively taxonomic studies must explore the great habitat heterogeneity in this floodplain, e.g., the littoral region and the extensive areas colonized by aquatic macrophytes, aiming to expand knowledge on the diversity of this family in the upper Paraná river floodplain.

planície de inundação do alto rio Paraná possui grande diversidade de rotíferos, com 288 táxons planctônicos registrados. Estudos realizados, nesse ecossistema, desde 1992, mostram que Lecanidae é a família mais especiosa, com 45 táxons registrados. Este trabalho teve como objetivo investigar a ocorrência dessa família em ambientes ainda não-estudados e consequentemente contribuir para a diversidade de rotíferos nessa planície de inundação. Foram registradas sete novas ocorrências de Lecane em amostras do plâncton: L. bifurca, L. rhytida, L. subtilis, L. crepida, L. bulla styrax, L. obtusa, e L. thienemanne. Embora os táxons descritos fossem encontrados no plâncton, essa família caracteriza-se por ser tipicamente não-planctônica. Dessa forma, visando ampliar o conhecimento sobre a diversidade dessa família na planície de inundação do alto rio Paraná, estudos exclusivamente taxonômicos devem explorar a grande heterogeneidade de hábitats presente nessa planície, como, por exemplo, a região marginal e as extensas áreas colonizadas por macrófitas aquáticas.

Species richness and geographic distribution of testate amoebae (Rhizopoda) in Brazilian freshwater environments / Riqueza de espécies e distribuição geográfica de amebas testáceas (Rhizopoda) em ambientes aquáticos continentais brasileiros - DOI: 10.4025/actascibiolsci.v29i2.525

The present study aimed to analyze the species richness of testate amoebae, as well as to describe their geographic distribution and different habitat types in Brazilian freshwater environments. Until now, 346 infrageneric taxa have been recorded, belonging to 13 families and 40 genera. In the Center-West region, 267 taxa were recorded; 188 taxa in the Southeast; 129 taxa in the South, 53 taxa in the North; and 18 taxa in Northeast region. A total of 282 taxa were recorded in plankton; 80 taxa in aquatic macrophytes; 81 taxa in sediment; and 73 taxa in moss/sphagnum. The results regarding testate amoebae species richness are not yet conclusive, given that most research on these organisms was carried out in central, southeastern and southern Brazil. The higher number of taxa observed in plankton may be due to the fact that most studies on testate amoebae in Brazil had been carried out in the planktonic compartment, including reservoirs, floodplain lagoons, channels, tributaries and rivers. In addition, the majority of studies with sediment samples were conducted in estuaries or coastal lagoons, where salinity is a restricting factor for the occurrence of these organisms.

Este trabalho visa realizar um levantamento da riqueza de espécies de amebas testáceas, bem como descrever a distribuição geográfica e a distribuição em diferentes tipos de habitats desses organismos em ambientes aquáticos continentais brasileiros. Até o momento, são registrados 346 táxons infragenéricos, pertencentes a 13 famílias e 40 gêneros. São registrados 267 táxons na região centro-oeste, 188 táxons na região sudeste, 129 táxons na região sul, 53 táxons na região norte e 18 táxons na região nordeste. São registrados 282 táxons no plâncton; 131 táxons em macrófitas aquáticas, 81 táxons no sedimento e 73 táxons em musgos/esfágnos. Os resultados sobre a riqueza de tecamebas não é ainda conclusiva, visto que a maioria das pesquisas foi conduzida nas regiões centro-oeste, sudeste e sul. O maior número de táxons registrados no plâncton pode ser em virtude de que a maioria dos estudos sobre tecamebas, no Brasil, ter sido realizada no compartimento planctônico, incluindo reservatórios, lagoas de várzeas, canais, tributários e rios. Além disso, a maior parte dos estudos, em amostras de sedimento, foi conduzida em estuários ou lagoas costeiras, onde a salinidade é um fator limitante para a ocorrência desses organismos.

Testate amoebae composition (Protozoa-Rhizopoda) from two São Paulo State creeks, including new records for Brazil - DOI: 10.4025/actascibiolsci.v27i2.1319 / Composição de amebas testáceas (Protozoa-Rhizopoda) de dois córregos do Estado de São Paulo, incluindo novos registros para o Brasil - DOI: 10.4025/actascibiolsci.v27i2.1319

Twelve monthly samplings were collected in São José do Rio Preto, São Paulo State, Brazil, with the purpose of evaluating the composition and the richness of the testate amoebae assemblage in two creeks. Despite the low richness observed (21 taxa), the results showed that eight taxa had not been recorded before in São Paulo State, which points out to the need of increasing the sampling effort in the state as well as the researchers qualification who should be able to identify such organisms. Difflugia corona ecornis and Difflugia lobostoma cornuta, constitute two new records for Brazil

Com o intuito de avaliar a composição e a riqueza da assembléia de amebas testáceas em dois córregos localizados no Noroeste paulista, foram realizadas amostragens mensais durante doze meses no distrito de Talhado, município de São José do Rio Preto, Estado de São Paulo. Os resultados mostraram que apesar do baixo valor de riqueza observado (21 táxons), oito táxons não haviam sido registrados anteriormente no Estado de São Paulo, o que evidencia a necessidade de se aumentar os esforços de coleta no estado além da qualificação de pesquisadores aptos na identificação de tais organismos. Dois táxons, Difflugia corona ecornis e Difflugia lobostoma cornuta, constituem novos registros para o Brasil

Planktonic heterotrophic nanoflagellates abundance in reservoirs of distinct trophic state - DOI: 10.4025/actascibiolsci.v27i1.1358 / Abundância de nanoflagelados heterotróficos no plâncton de reservatórios com distintos graus de trofia - DOI: 10.4025/actascibiolsci.v27i1.1358

The aim of this study was to investigate the influence of the trophic state on the planktonic heterotrophic nanoflagellates abundance from three reservoirs of the State of Paraná: Iraí (eutrophic), Rosana (mesotrophic) and Chavantes (oligotrophic). The samples were collected during dry (July) and rainy (November) periods in 2001 and were taken at the sub-surface and mixing layers of the lacustrine zone of the reservoirs. Heterotrophic nanoflagellates abundance was determined by epifluorescence microscopy, after staining with Dapi, and cells volumes were calculated aiming to estimate biomass, using a cell volume-to-carbon conversion factor. Higher values of density and biomass were observed in Iraí Reservoir, the most eutrophic environment, whereas the lower ones were registred in Chavantes Reservoir, in both studied periods. In all reservoirs, a clear vertical pattern was observed, with higher values in the sub-surface layer. The results suggested that the trophic state influenced strongly the abundance patterns of planktonic heterotrophic nanoflagellates, indicating that the resources available determined the patterns. In other words, although there certainly is a predation pressure on the heterotrophic nanoflagellates community, it is not enough to prevent that the increase of resources determine a significant enlargement in these organisms abundance

O objetivo deste trabalho foi investigar a influência do grau de trofia sobre a abundância dos nanoflagelados heterotróficos no plâncton de três reservatórios do Estado do Paraná: Iraí (eutrófico), Rosana (mesotrófico) e Chavantes (oligotrófico). As coletas foram realizadas durante os períodos de estiagem (julho) e chuva (novembro) de 2001, à subsuperfície e camada de mistura da região lacustre desses reservatórios. A abundância dos nanoflagelados heterotróficos foi determinada sob microscópio de epifluorescência, utilizando o Dapi como corante, e os volumes celulares calculados objetivando estimar a biomassa, usando um fator de conversão volume celular-carbono. Maiores valores de densidade e biomassa foram observados no reservatório Irai, enquanto que os menores foram registrados em Chavantes, em ambos os períodos estudados. Em relação à distribuição vertical, maiores valores de densidade e biomassa foram encontrados, em geral, à subsuperfície. Os resultados sugerem que o grau de trofia influenciou fortemente os padrões de variação da abundância (densidade e biomassa) dos nanoflagelados heterotróficos planctônicos, indicando que a disponibilidade de recursos alimentares prevaleceu na determinação de tais padrões. Em outras palavras, embora uma pressão de predação sobre a comunidade de nanoflagelados heterotróficos esteja certamente ocorrendo, não é suficiente para evitar que o

Abundance of planktonic ciliates in a cascading reservoirs of the Paranapanema River, Brazil - DOI: 10.4025/actascibiolsci.v26i4.1532 / Abundância de ciliados planctônicos em reservatórios em cascata do rio Paranapanema, Brasil- DOI: 10.4025/actascibiolsci.v26i4.1532

The present study aimed to investigate the spatial and temporal distribution patterns of density and biomass of the planktonic ciliates, in a reservoir serie of the Paranapanema River (22o 18 - 23o 35 S; 49o 30 - 52o 50 W). We intend to test the hypothesis that, along reservoirs serie, there is a decrease of abundance from river towards the dam. Samplings were carried out in seven reservoirs, during 2001, in two distinct hydrological periods, at subsurface of the lacustrine region, using a Van Dorn bottle (5 liters). Aliquots from one liter were obtained and fixed with a fixing solution compounded by alkaline lugol, formaldehyde and sodium tiosulfate. Obtained values for ciliates abundance (density and biomass) in different reservoirs (0.4 to 16.6 cells.mL-1; 0.23 to 20.7 µg.C.L-1, respectively) were inferior to results found in eutrophic environments, but similar to those registered in oligo-mesotrophic environments. Analysis of the abundance distribution results, along reservoirs serie, did not corroborate the hypothesis of decreasing density and biomass from upstream to dowstream, due to an expectancy of a possible oligotrophication downriver. In relation to different functional groups of ciliates, it was verified the dominance of Oligotrichida, mainly small sized individuals ( 30 µm).

O presente estudo teve como objetivo investigar os padrões de distribuição espacial e temporal da densidade e biomassa dos ciliados planctônicos em reservatórios em cascata do rio Paranapanema (22o 18 - 23o 35 S; 49o 30 - 52o 50 W). Pretende-se testar a hipótese de que, ao longo da série de reservatórios, observa-se um decréscimo da abundância desses organismos no sentido montante-jusante. Para tal, foram coletadas amostras em sete reservatórios, no ano de 2001, em dois períodos hidrológicos distintos, à sub-superfície da região lacustre, com o auxílio de uma garrafa de Van Dorn de 5 litros. Alíquotas de um litro foram obtidas e sua fixação realizada com solução fixadora composta de lugol alcalino, formol e tiossulfeto de sódio. Os valores obtidos para a abundância (densidade e biomassa) de ciliados nos diferentes reservatórios (0,4 a 16,6 células.mL-1; 0,23 a 20,7 µg.C.L-1, respectivamente) foram inferiores aos resultados encontrados em ambientes eutróficos, porém similares àqueles registrados em ambientes oligo-mesotróficos. A análise dos resultados de distribuição da abundância ao longo da série de reservatórios não corroborou a hipótese preconizada de uma diminuição de densidade e biomassa no sentido montante-jusante, em função da expectativa de uma possível oligotrofização rio abaixo. Em relação aos diferentes grupos funcionais de ciliados, foi constatada a dominância

Testate amoebae abundance in plankton samples from Paraná State reservoirs - DOI: 10.4025/actascibiolsci.v26i4.1522 / Abundância de tecamebas no plâncton de reservatórios do Estado do Paraná- DOI: 10.4025/actascibiolsci.v26i4.1522

This study aimed to investigate patterns of spatial and temporal distribution of testate amoebae (Rhizopoda) abundance in plankton of different reservoirs of Paraná State and the importance of hydrodinamical and morphometrical factors on determining these patterns. Thirty reservoirs studied are located in six different watersheds, including environments with variable area, morphometry and age. Sampling were carried out in July and November 2001, dry and rainy seasons, respectively. Samples were obtained at the surface of reservoirs, in the lacustrine region, using a motorized pump (600 liters per sample) and a plankton net with a mesh size of 68µm. Testate amoebae were registered in 23 of 30 reservoirs.Higher density were observed in JMF, Salto do Meio, Melissa, Mourão and Salto do Vau reservoirs, during dry season, and JMF, Salto Osório, Salto do Meio and Melissa reservoirs, during wet season These reservoirs present similar characteristics, as reduced depth and morphometric dimensions Besides that, most of them have hydrodynamical features similar to lotic environments, due to presenting high current velocity. On the other hand, testate amoebae were absent or presented low density, in general, in reservoirs with higher dimensions and depth. Instead of expected, seasonally, higher densities values were observed during dry season, for the most of studied reservoirs. These resu

Este trabalho teve o objetivo de investigar os padrões de distribuição espacial e temporal da abundância de tecamebas (Rhizopoda) no plâncton de diferentes reservatórios do Estado do Paraná bem como a importância de fatores hidrodinâmicos e morfométricos na determinação desses padrões. Os 30 reservatórios estudados estão localizados em seis diferentes bacias, incluindo ambientes com áreas, morfometrias e idades variáveis. As amostragens foram realizadas em julho e novembro de 2001, períodos de estiagem e chuvoso, respectivamente. As amostras foram obtidas à superfície dos reservatórios, na região lacustre, utilizando-se uma bomba (600 litros por amostra) e uma rede de plâncton com malhagem de 68 um. As tecamebas foram registradas em 23 reservatórios. Maiores densidades foram encontradas nos reservatórios JMF, Salto do Meio, Melissa, Mourão e Salto do Vau, durante o período de estiagem, e JMF, Salto Osório, Salto do Meio e Melissa, durante o período chuvoso. Esses reservatórios apresentam características similares, como reduzidas profundidades e dimensões morfométricas. Além disso, a maioria deles têm características hidrodinâmicas similares a de ambientes lóticos, por apresentarem alta velocidade de corrente. Por outro lado, as tecamebas foram ausentes ou presentes em baixas densidades, em geral, nos reservatórios com maiores dimensões e profundidade. Ao contrário do esperado,

Structure and dynamics of rotifers in Corumbá reservoir, state of Goiás-Brazil - DOI: 10.4025/actascibiolsci.v25i1.2079 / Estrutura e dinâmica dos rotíferos no reservatório de Corumbá, Estado de Goiás, Brasil - DOI: 10.4025/actascibiolsci.v25i1.2079

The aim of this study was to investigate patterns of richness, abundance and diversity of rotifers in a recently formed reservoir, Corumbá reservoir in the state of Goiás. 104 taxa were identified and seven of them were constant. Brachionidae was the most diverse, particularly in the main part of the reservoir channel. The greatest densities were found in the riverine and transitional zones and in the arms of the reservoir. The diversity was higher in the riverine zone and in one of the tributaries. Rotifer abundance shows significant correlation with Cryptophyceae, Cyanophyceae, Chlorophyceae abundances, and primary production, expressed beyond the first Component Principal Axes. Results suggested that the hydrodinamic variation, typical of the spatial heterogeneity of the area under study, plus food available are determining factors to the structure of the rotifer assemblage

Nesse estudo objetivou-se investigar os padrões de riqueza, abundância e diversidade da assembléia de rotíferos em um reservatório recém-formado do Estado de Goiás. Foram identificados 104 táxons infragenéricos, sendo sete táxons constantes, destacando-se Brachionidae, principalmente no corpo central do reservatório e em um dos braços. As maiores densidades foram registradas nos trechos superior e intermediário do reservatório e nos braços, preferencialmente à superfície, e no período de estiagem. A diversidade foi mais elevada no trecho fluvial e em um dos tributários. A abundância dos rotíferos apresentou correlações significativas com as densidades de Cryptophyceae, Cyanophyceae e Chlorophyceae, além do primeiro eixo da ACP, que resumiu a variação espaço-temporal da produção fitoplanctônica. Os resultados apresentados sugerem que as variações hidrodinâmicas, características da heterogeneidade espacial da área de estudo, e a qualidade e quantidade de alimento disponível são fatores determinantes para a estrutura da assembléia de rotíferos

Composition and abundance of Cladocera (Crustacea) assemblages associated with Eichhornia azurea (Swartz) Kunth stands in the Upper Paraná River floodplain - DOI: 10.4025/actascibiolsci.v25i1.2118 / Composição e abundância da assembléia de Cladocera (Crustacea) associada à macrófitas aquáticas (Eichhornia azurea) na planície de inundação do alto rio Paraná - DOI: 10.4025/actascibiolsci.v25i1.2118

The composition and abundance of cladocerans associated with Eichhornia azurea (Pontederiaceae) in different environments of the Upper Paraná River floodplain were achieved. Collecting was undertaken from March 1992 to February 1993, at eight stations, two river-lake floodplain systems, Baía and Ivinheima, and in the Cortado Channel, a Paraná River-associated system. Thirty-one species of cladocerans were identified. The greatest number of species and highest abundance values were registered in floodplain environments, probably due to a great number of habitats made up of aquatic macrophytes and to the high connectivity among different environments. In the Paraná system there are some great quantities of macrophytes on its banks, however a small number of cladocerans species occurs, contrastingly to the floodplain environments. This may happens due to the high speed of the river water that restricts the development of large cladoceran populations typical of the littoral region. The great number of plankton species in this system suggests that aquatic macrophytes are like a haven to these species since the vegetation greatly reduces the speed of the water current

Foram estudadas a composição e abundância da assembléia de cladóceros associados à Eichhornia azurea (Pontederiaceae) em distintos ambientes da planície de inundação do alto rio Paraná. As coletas foram realizadas durante o período de março/92 a fevereiro/93, em oito estações, localizadas em dois sistemas rio-lagoa, Baía e Ivinheima, caracterizados como sistemas de várzea, e em um sistema associado ao rio Paraná, o canal Cortado. Foram identificadas 31 espécies de cladóceros. O maior número de espécies bem como os mais elevados valores de abundância foram registrados nos ambientes de várzea, provavelmente devido a grande quantidade de hábitats formados pelas macrófitas aquáticas, além da grande conectividade existente entre os diferentes ambientes. Por outro lado, no sistema Paraná, embora ocorra uma grande quantidade de macrófitas em suas margens, não foi registrado um elevado número de espécies como o de ambientes de várzea, possivelmente devido a maior velocidade de corrente que limita o desenvolvimento de grandes populações de cladóceros típicos de região litorânea. A maior representatividade de espécies planctônicas nesse sistema sugere que as macrófitas aquáticas atuam como refúgio para essas espécies, tendo em vista que essa vegetação reduz substancialmente a velocidade de corrente