The influence of physical instream spatial variability on Chironomidae (Diptera) assemblages in Neotropical streams

Abstract

In this study, the Chironomidae assemblages were studied in order to test the following hypotheses: a) mesohabitat type and substrate complexity affect the richness, abundance, and composition of the fauna; b) mesohabitat type is a good predictor for Chironomidae composition. To test the hypotheses, experiments were carried out in two mesohabitats (riffle and pool) using two substrate complexities (high and low) in 12 streams from Central Brazil. The mesohabitat type and substrate complexity did not affect the richness and abundance of the local fauna. The mesohabitat affected the faunistic composition. The assemblages of riffles and pools were distinct. Indicator Species Analysis showed that Paratendipes sp., Polypedilum sp. 2, Pentaneura sp., Rheotanytarsus sp. 1, Corynoneura sp. 2, Cricotopus sp. 2, Lopescladius sp., Nanocladius sp. 2, Parametriocnemus sp., and Thienemanniella sp. had preference for riffles and Chironomus sp., Ablabesmyia sp. 1, Ablabesmyia sp. 2, Djalmabatista sp., Fittkauimyia sp., and Labrundinia sp. for pools. Our results highlight the importance of physical instream variability on fauna structuring, suggesting that habitat homogenization due to anthropic action may cause drastic effects on the diversity of chironomids and, probably, other benthic macroinvertebrates. Therefore, maintaining instream morphology, including the different mesohabitats, is fundamental for biodiversity conservation in streams.

Short comment on Chironomidae (Insecta: Diptera) from Brazil’s Federal District

“…Studies from other Cerrado regions have yielded higher generic richness, with 45 genera found at the State of Goiás (Mazão and Bispo 2016) and 36 at São Paulo State (Saito and Fonseca-Gessner 2014). This supports our suggestion that the true richness value in the Federal District is likely much higher than presented here.…”

“…These genera usually are associated with good environmental conditions (Eintrekin et al 2007, Saito andFonseca-Gessner 2014). The abundance of Stenochironomus in Neotropical streams is quite variable as some authors report their rarity (Gonçalves Jr et al 2007), while others have documented great abundances of this genus (Saito andFonseca-Gessner 2014, Mazão andBispo 2016). Stenochironomus larvae are important indicators for the preservation status of riparian forests, as they are known as shredders (Silva et al 2009, Santos andRodrigues 2015).…”

“…The limited knowledge in chironomid biodiversity is not necessarily due to lack of research conducted within the Cerrado, but rather the extensive area that the biome occupies. Additionally, few focus exclusively on Chironomidae (Sonoda et al 2009a, Sonoda et al 2009b, Saito and Fonseca-Gessner 2014, Mazão et al 2016. When considering the Federal District region, we notice that most studies analyze the entire aquatic entomofauna and the influence of human activities on Figure 1.…”

Back from the Past: DNA Barcodes and Morphology Support Ablabesmyia americana Fittkau as a Valid Species (Diptera: Chironomidae)

“…Later, Freeman [18] and Roback [19] relegated Ablabesmyia to subgeneric status in Pentaneura (Philippi, 1865), while Fittkau [20] gave it full generic status. Ablabesmyia larvae are predators, and are recorded in many ecological studies (e.g., [21][22][23][24]). The genus is one of the most distinctive and well-defined genera within the tribe Pentaneurini, with adult males possessing a homologous complex of dorsomedial blades and lobes in their genitalia unique to the taxon [25,26].…”

Human impact on large rivers: the influence of groynes of the River Oder on larval assemblages of caddisflies (Trichoptera)

“…Because of the increasing instream habitat complexity that positively affects the species richness and abundance of the macrofauna (e.g. Boyero, 2003;Mazão & Conceição Bispo, 2016), we can expect successful colonisation of caddisfly species with lentic habitat preferences in the groyne fields. The potential sources of lentic species in a river valley are oxbows.…”