Distribution of Chironomidae in a Semiarid Intermittent River of Brazil

Abstract

The effects of the intermittency of water flow on habitat structure and substrate composition have been reported to create a patch dynamics for the aquatic fauna, mostly for that associated with the substrate. This study aims to describe the spatial distribution of Chironomidae in an intermittent river of semiarid Brazil and to associate assemblage composition with environmental variables. Benthic invertebrates were sampled during the wet and dry seasons using a D-shaped net (40 cm wide and 250 μm mesh), and the Chironomidae were identified to genus level. The most abundant genera were Tanytarsus, Polypedilum, and Saetheria with important contributions of the genera Procladius, Aedokritus, and Dicrotendipes. Richness and density were not significantly different between the study sites, and multiple regression showed that the variation in richness and density explained by the environmental variables was significant only for substrate composition. The composition of genera showed significant spatial segregation across the study sites. Canonical Correspondence Analysis showed significant correspondence between Chironomidae composition and the environmental variables, with submerged vegetation, elevation, and leaf litter being important predictors of the Chironomidae fauna. This study showed that Chironomidae presented important spatial variation along the river and that this variation was substantially explained by environmental variables associated with the habitat structure and river hierarchy. We suggest that the observed spatial segregation in the fauna results in the high diversity of this group of organisms in intermittent streams.

Spatial Distribution of Zooplankton Diversity across Temporary Pools in a Semiarid Intermittent River

“…However, the role of the hydrological disturbances in the spatial dynamics of zooplankton and the habitat variation in intermittent streams has received little attention. Studies indicate that water flow and its effects on habitat structure play a major role in producing and maintaining a mosaic of pools and microhabitats that can be used for colonization and refugia for aquatic organisms [22,23]. This dynamic makes intermittent streams complex and heterogeneous systems, with organisms distributed in patches determined by environmental conditions affecting the fauna hierarchically [24,25].…”

Analysis of the error associated with the subsampling of Chironomidae in an intermittent stream of semi-arid Brazil

“…However, it is important to ensure that such subsampling methods are representative of the sample and the study area, and that they are being interpreted bearing in mind the limitations of the subsampling technique (Farias et al 2012, Ligeiro et al 2012. In the Brazilian semi-arid streams, larger morphotypes are represented mostly by Chironomus, Dicrotendipes and Clinotanypus (e.g.…”

“…In the Brazilian semi-arid streams, larger morphotypes are represented mostly by Chironomus, Dicrotendipes and Clinotanypus (e.g. Farias et al 2012. Nonetheless, other systems report other types of chironomids and consequently different larger morphotypes, such as Cryptochironomus, Axarus and Alotanypus (e.g.…”

“…Only then, individuals can be counted and the data used for ecological studies of community structure (Farias et al 2012). This process is both labor and time-consuming, which often makes the counting of all individuals an unrealistic demand for laboratory work.…”

First record of Lopescladius Oliveira, 1967 (Chironomidae: Orthocladiinae) in the Piranhas-Açu River basin, Brazil, with ecological notes on its habitat use

“…In intermittent streams of semi-arid Brazil, three subfamilies (Chironominae, Tanypodinae, Orthocladiinae) with approximately 26 genera have been recorded. The subfamily Orthocladiinae is poorly represented with only three genera (Farias et al 2012;Rocha et al 2012;Soares et al 2013).…”