Copépodes (Crustacea, Calanoida, Cyclopoida) planctônicos em reservatórios profundos e dendríticos: efeitos do tempo de residência e da idade de formação

Abstract

.p1-8 Some ecological attributes of planktonic copepods (composition, diversity, abundance and its relations with limnological variables) were compared in two deep and dendritic reservoirs, 470km from each other, with contrasting water retention time (WRT) and ages of construction. Data were grouped from two different studies: samples were collected monthly between March/00 to February/01, on the Salto Caxias Reservoir (Iguaçu River), and tri-monthly between January/00 to October/01, on the Chavantes Reservoir (Paranapanema River). Eight species of Calanoida and six of Cyclopoida were identified in both reservoirs. The highest richness was observed in Salto Caxias (12 taxa) when compared with Chavantes (8 taxa), and six species were exclusive to Salto Caxias and two from Chavantes. Salto Caxias was studied one year after the construction, consequently with higher nutrients values in this period and showed generally high mean values of Copepoda (nauplius, copepodits and adults) than Chavantes, which is 38 years old. Some parameters as transparency, conductivity, turbidity and total nitrogen were significantly related with copepod abundance. New formation and sufficient long WRT could be an important cause for the highest richness of Calanoida and total abundance of individuals in Salto Caxias Reservoir.

Copepod assemblage structure (Crustacea: Copepoda) along a longitudinal environmental gradient in a tropical river-floodplain system, Brazil

“…Alterations in physical and chemical factors caused by reservoir construction promote changes in food composition, altering the community structure of copepods (Perbiche-Neves et al, 2014). These changes can determine the type of feeding of copepods and favor the development of certain species, influencing on the community structure (Matsumura-Tundisi & Tundisi, 2003;Napiórkowski et al, 2006).…”

Do changes in the water regime determine the abundance of the copepod trophic group in a Neotropical floodplain?

“…Still in 2000, omnivorous copepods had a positive relationship with rotifer abundance. This relationship may be associated with the fact that omnivorous copepods, such as cyclopoids, have a broad food spectrum with raptorial habit (Perbiche-Neves et al, 2014). According to Brandl, (2005), due to their small size and restricted mobility, rotifers are considered as the preferred food items in the diet of omnivorous species.…”

Baixa riqueza zooplanctônica indicando condições adversas de seca e eutrofização em um reservatório no Nordeste do Brasil

“…Nos três estudos acima citados houve dominância de B. calicyflorus e T. decipiens, entre outras, porém em 2010 N. cearensis foi detectada no corpo central do reservatório (Perbiche-Neves et al, 2014). No presente estudo parece ser a única espécie de Calanoida ocorrente no período em que o reservatório foi estudado, suportando os trabalhos que associam essa espécie com ambientes eutrofizados ou com condições mais severas, como as de estiagem e temperaturas elevadas.…”