Chironomid (Insecta: Diptera) assemblages along an Andean altitudinal gradient

Abstract

Chironomidae are an abundant, diverse and ecologically important group common in mountain streams worldwide, but their patterns of distribution have been poorly described for the Andes region in western-central Argentina. Here we examine chironomid assemblages along an altitudinal gradient in the Mendoza River basin to study how spatial and seasonal variations affect the abundance patterns of genera across a gradient of elevation, assess the effects of environmental variables on the chironomid community and to describe its diversity using rarefaction and Shannon's indices. Three replicate samples and physicochemical parameters were measured seasonally at 11 sites in 2000 and 2001. Twelve genera of chironomid larvae were identified, which belonged to 5 subfamilies. Chironomid composition changed from the headwaters to the outlet and was associated with changes in altitude, water temperature, substrate size and conductivity. We found a pronounced seasonal and spatial variation in the macroinvertebrate community and in physicochemical parameters. Environmental conditions such as elevated conductivity levels and increased river discharge occurring during the summer produced low chironomid density values at the sampling sites. The rarefaction index revealed that the sampling sites with highest richness were LU (middle section of the river) and PO (lower section). However, Shannon's diversity index indicated that LU had the lowest diversity as a consequence of the dominance of Cricotopus over the other genera found. We attribute the low diversity found in our aquatic system to the aridity of the sampling area, as has been demonstrated in studies of other similar lotic systems in this mountain region.

Madicolous Chironomidae from the Brazilian Atlantic Forest: a checklist with notes on altitudinal distributions (Diptera, Insecta)

“…Compositional changing in chironomid assemblages along altitudinal gradients have been verified by many researchers worldwide (McKie et al 2005, Tejerina and Malizia 2012, Henriques-Oliveira and Nessimian 2010, Scheibler et al 2014, Robinson et al 2016, Matthews-Bird et al 2016). In mountain ecosystems the occurrence of chironomid species can be influenced by environmental changes related to altitude variation, such as temperature and oxygen availability (Oliver 1971, Pinder 1986, Eggermont and Heiri 2012), dispersal capacity (Ashe et al 1987), historical events (McKie et al 2005, Allegrucci et al 2006, Krosch et al 2011) or other regional particularities (Körner 2007).…”

Modelling beta diversity of aquatic macroinvertebrates in High Andean wetlands

“…Taxa pointed out here as characteristics from a given class have already been reported in other surveys from comparable regions. This is the case of Podonominae, which was positively related to the altitude (Tejerina and Molineri, 2007;Scheibler et al, 2008) and was considered as a cold stenothermal group from Andean rivers (Acosta Rivas, 2009;Epele et al, 2012;Medina et al, 2008;Scheibler et al, , 2014Tejerina and Molineri, 2007;Rodríguez Garay et al, 2015). Dolichopodidae has been consistently recovered as indicator of hyperfresh environments.…”

Efecto de la condición hídrica de vegas altoandinas del desierto transicional de Chile sobre algunas características comunitarias de su dipterofauna

“…En este trabajo se registró la presencia de 29 familias, un número ligeramente mayor al encontrado en humedales andinos tropicales (23) (Sánchez & Amat-García, 2005). Aunque no estudiado, posiblemente el valor de riqueza-F encontrado en este trabajo se debe a que las vegas ofrecen un conjunto diverso de microhábitats y recursos alimentarios en abundancia para su colonización y explotación, como ha sido descrita para humedales de otras latitudes (Acosta & Prat, 2010;Scheibler et al, 2014). Por otra parte, las diferencias encontradas en la riqueza-F entre las vegas de este estudio y aquellas reportadas en la literatura chilena, probablemente reflejan las diferencias en intervención humana.…”