Macroinvertebrate fauna associated with Pistia stratiotes and Nymphoides indica in subtropical lakes (south Brazil)

Abstract

This study was carried out at the Biguás and Polegar lakes, both small environments but at different successional stages. The main objective was to characterize the macroinvertebrate community associated to the aquatic macrophyte stand in each lake in order for this community, the environmental conditions and their water quality to interact. The samples were taken in 2003. The abiotic variables of N and P totals, the temperature, electrical conductivity, pH and dissolved oxygen, as well as the determined clorophyll a concentration were measured. Macroinvertebrates were sampled with a 500 µ mesh size net, separated under a stereomicroscope and identified at the lowest possible taxonomic level, and their densities were shown as the number of individuals per 100 g of macrophyte dry weight. The Shannon-Wiener Diversity Index (H'), Pielou evenness (J), frequency of occurrence, abundance and taxa richness were calculated for each invertebrate community. The Lago dos Biguás is undergoing a process of eutrophication and during the study presented a large Pistia stratiotes stand. The Lago Polegar is oligotrophic and had only a small Nymphoides indica bankwe. The macrophyte associated invertebrate communities in each lake were considered significantly different (p < 0.05). Sixty seven taxa were found for the Lago dos Biguás and 32 for the Lago Polegar. For both lakes, most of the taxa were considered rare, with a low dominance in a few months. The taxa with highest densities at Lago dos Biguás were Chironomidae, Daphniidae and Cyclopidae, and Oligochaeta, Chironomidae and Coenagrionidae for Lago Polegar.Keywords: macroinvertebrates associated with macrophytes, communities, subtropical lakes. Fauna de macroinvertebrados associados a Pistia stratiotes e Nymphoides indica em lagos subtropicais (sul do Brasil) ResumoEste estudo foi realizado nos lagos dos Biguás e Polegar, ambientes de pequenas dimensões que se encontram em diferentes estágios sucessionais. O objetivo principal foi caracterizar a comunidade de macroinvertebrados, que vive associada ao estande de macrófitas aquáticas encontrado em cada um dos lagos, na tentativa de obter relações entre a comunidade, a saúde dos ambientes e a qualidade de água. As coletas foram feitas durante o ano de 2003. Em cada lago, foram avaliadas as concentrações de N e o P totais, o pH, temperatura, oxigênio dissolvido, condutividade elétri-ca, e determinadas as concentrações de clorofila a na água. A malha utilizada para a separação dos macroinvertebrados foi de 500 µ e os resultados de densidade foram expressos em 100 gramas de peso seco de macrófita. A triagem foi realizada sob estereomicroscópio e os organismos identificados até o menor nível taxonômico possível. Para cada comunidade foram calculados o Índice de Diversidade de Shannon-Wiener (H'), a homogeneidade de Pielou (J), a freqüência de ocorrência, a abundância e a riqueza de taxa. O Lago dos Biguás, em processo de eutrofização, apresentou durante o período estudado um grande estande de Pistia stratiotes. O Lago Poleg...

Water quality and communities associated with macrophytes in a shallow water-supply reservoir on an aquaculture farm

“…These results can mostly be explained by macrophytes habitat and morphology present in this shallow reservoir, which both macrophytes are floating perennial aquatic plant or free-floating perennial or annual macrophytes. The number of planktonic taxa found was higher than those pointed by Albertoni et al (2007) and lower than found by Onsem et al (2010).…”

“…The macrophytes stands support epiphytic algae and animals as well as a variety of associated mobile animals, including zooplankton, macrofauna and fish (Albertoni et al, 2007;Christie et al, 2009). Macrophytes provide habitat and refuge for zooplanktonic filter feeders to maintain topdown control on the phytoplankton (Sandilands and Hann, 1997).…”

Orthoptera assemblages associated with macrophytes of floodplain lakes of the Paraná River

“…On the other hand, the three species of Ensifera that were registered were described as the insects that inhabit moist places and those near to the water: Phlugis sp., Conocephalus sp., and Scudderia sp. The crickets collected in this study were cited by other authors as being a part of the insect community living on floating aquatic plants (Carbonell 1980;Albertoni et al 2007). …”

Diet of Lontra longicaudis (Olfers, 1818) (Carnivora: Mustelidae) in three limnic systems in Southern Rio Grande do Sul State, Brazil

“…These studies provide data on the species diet spectrum, considering that the environments with different physiognomies host different types of potential preys (Ricklefs 2003). The coastal plain of Rio Grande do Sul State, southern Brazil is hydrologically characterized by the existence of shallow freshwater ecosystems such as streams, lagoons and wetlands (Vieira and Rangel, 1988;Albertoni et al 2007). In addition to these natural water bodies, artificial systems represented by the drainage channels and anthropogenic shallow lakes are also present in the region.…”

“…In addition to these natural water bodies, artificial systems represented by the drainage channels and anthropogenic shallow lakes are also present in the region. Channels built for the drainage and pluvial water flow are common in the coastal cities of Rio Grande do Sul State (Albertoni and Palma-Silva 2006) while a set of anthropogenic shallow lakes are present in an urban area in the city of Rio Grande (Votto et al 2006;Albertoni et al 2007). The objective of the present work was to study the diet of L. longicaudis in three distinct limnic systems in southern Rio Grande do Sul State, aiming on an approximation about the diet spectrum of the species in this region.…”