Rotifers of the upper Paraná River floodplain: additions to the checklist

Abstract

Rotifers present a high diversity in freshwater ecosystems. This study registered 11 genera and 42 species, new records for the Upper Paraná River floodplain. These results showed an increase in rotifer diversity in this ecosystem from 184 to 230 species. Among them some were registered only in the rivers and others in the lagoons. Thirty-seven species occurred in the littoral zone and 34 species in the pelagic; 3 species were registered only in the former zone and 2 species only in the latter. The lagoons presented the greatest richness, probably because of the greater stability, low current velocity, and the extensive aquatic macrophyte banks in the littoral zone of these environments as compared to those of the rivers. The highest number of species in the littoral habitats occurred due to the greater influence of shoreline vegetation, which allows greater habitat diversification. This fact contributed to the occurrence of non-planktonic species in the zooplankton samples.Key words: rotifers, floodplain, richness, new records, Paraná river. RESUMO Rotíferos da planície de inundação do alto rio Paraná: novas ocorrênciasOs rotíferos apresentam elevada diversidade em ambientes aquáticos continentais. Este estudo mostra novas ocorrências de 12 gêneros e 42 espécies desse grupo na planície de inundação do alto rio Paraná, o que incrementa o registro de 184 espécies para 230 espécies nesse ecossistema. Entre esses novos registros, algumas espécies ocorreram somente em lagoas e outras, apenas em rios. Foram encontradas 37 espécies na região litorânea e 34 na região pelágica dos ambientes estudados, dentre estas 3 espécies foram registradas apenas na primeira região e somente 2 na segunda região. As lagoas apresentaram os maiores valores de riqueza, provavelmente em razão da grande estabilidade, menor velocidade de corrente e presença de extensos bancos de macrófitas aquáticas. A presença de vegetação marginal permite grande diversificação de habitats, contribuindo para a ocorrência de um número expressivo de espécies na região litorânea. Esse fato contribuiu para a ocorrência de espécies não planctônicas no zooplâncton.Palavras-chave: rotífero, planície de inundação, riqueza, novas ocorrências, rio Paraná.

Effect of Spatial Heterogeneity on Zooplankton Diversity: A Multi-Scale Habitat Approximation in a Floodplain Lake

“…Emergent macrophytes play a similar role, especially in turbid ecosystems, where submerged macrophytes are limited (Iglesias et al ., ; Cazzanelli et al ., ). Finally, free‐floating macrophytes reduce light penetration and oxygen availability in the water column (de Tezanos Pinto et al ., ; O'Farrell et al ., ) and while reducing phytoplankton diversity (O'Farrell et al ., ) are associated to rich communities of zooplankton (Serafim et al ., ; Gazulha et al ., ; Villabona‐González et al ., ), macroinvertebrates (Poi de Neiff, ; Fontanarrosa et al ., ) and fishes (Agostinho et al ., ; Teixeira de Mello et al ., ).…”

Structure of the zooplankton communities in macrophytes stand of a Neotropical floodplain (the Paraná River, Brazil)

“…As for the rotifers, the non‐planktonic Epiphanidae and Dicranophoridae were recorded only in the high water period. A high richness of non‐planktonic species was also confirmed, in the high water, among the plankton of nine lakes with different degrees of connectivity to the main river of the Upper Paraná River floodplain . These authors suggest that these species were not only displaced to the central regions of the lakes in this period, but were also able to develop large populations.…”

A Seasonal Study Reveals the Occurrence of Exotic Rotifers, the River Antigua, Veracruz, Close to the Gulf of Mexico

“…We observe that most lecanids in the samples are from the river banks. The non‐planktonic rotifers that flourish in the aquatic vegetation near the river banks are possibly being drifted out into the rivers as they flow (De Ridder, ; Ferrari et al, ; Serafim et al, ). Also, flood plains are known to be rich in rotifer habitats (Serafim et al, ).…”

“…The nonplanktonic rotifers that flourish in the aquatic vegetation near the river banks are possibly being drifted out into the rivers as they flow (De Ridder, 1984;Ferrari et al, 1989;Serafim et al, 2003). Also, flood plains are known to be rich in rotifer habitats (Serafim et al, 2003). Recently, Sharma (2014) found 131 species of rotifers of which 32% were lecanids in the Brahmaputra river flood plains.…”