Ecology of benthic crustaceans in the Cautin river (38°S, Araucania region, Chile)

Abstract

The Cautin river is located in the Araucania region, Chile (38°S), and is characterized by alterations through human interference in its surrounding basin, by the presence of introduced salmonids, and by its mixed regime, which originates from melting snow in summer and rains in winter. The fauna of this river includes an invertebrate fauna composed of both endemic and widespread species, which has, however, been only poorly studied until now. The aim of the present study was to make a review of the ecological role of the benthic inland water crustaceans of the River Cautin, in order to understand their importance in the ecosystem of the river. The literature revealed the presence of abundant populations of amphipods and freshwater crabs as well as of aquatic insects along the river’s course. Many of these crustaceans are prey for both introduced salmonids and native fishes. Similar results have been reported for other southern Argentinean and Chilean Patagonian rivers.

First report of inventory and role of macroinvertebrates and fish in Cautín river (38° S, Araucania region Chile)

“…The central and southern-central Chilean rivers (33-38°S) are characterized by their mixed regime, i.e., their discharge originates from winter rains and snow melting in summer. As a result of the combined conditions of relatively large quantities of water all year round and the fact that their courses run in mountainous regions and they flow rapidly in ocean showing a markedly turbulent flow (Niemeyer and Cereceda, 1984;Arenas, 1995;Vega et al, 2017). These circumstances have generated, and still continue to generate, a specific composition in the benthic communities that are adapted to these particular flow conditions (Figueroa, 2000;Colin et al, 2012;Piedra et al, 2012).…”

“…The literature about macroinvertebrates in this kind of rivers is quite fragmented, and mainly describes the presence of Malacostraca such as amphipods of the genus Hyalella (S.I. Smith), freshwater crabs of the genus Aegla (Leach, 1820), and the southern Chilean river prawn, Samastacus spinifrons (Phillippi, 1882) (De los Ríos-Escalante et al, 2012;Jara, 2013;Rudolph, 2013), and Diptera, Trichoptera and Ephemeroptera larval stages (Figueroa, 2000;Figueroa et al, 2003Figueroa et al, , 2007, many of these groups are currently endangered due to human-induced alterations in their habitats and the introduction of alien salmonids species since 1914 (Golusda, 1907(Golusda, , 1927Barros, 1931;Jara et al, 2006;Encina et al, 2017;Vega et al, 2017). The (introduced) salmonids, specifically, constitute non-selective, active predators (Soto et al, 2006(Soto et al, , 2007Fierro et al, 2012Fierro et al, , 2015Fierro et al, , 2016Piedra et al, 2012;Valdovinos et al, 2012;Vargas et al, 2010Vargas et al, , 2015.…”

Standard culture of Paratanytarsus grimmii Schneider, 1885 (Diptera: Chironomidae), for its use in toxicity bioassays.

“…In this scenario, if it is considered that many central Chilean rivers are exposed to pollution to different kinds of human activities (Figueroa et al, 2003(Figueroa et al, , 2007(Figueroa et al, , 2010(Figueroa et al, , 2013. If these ecosystems have many endemic species (Encina et al, 2017c;Vega et al, 2017), it would be necessary first do a specific characterization at species level of species of each site, as previous step for culture (Encina et al, 2017a, b) and bioassays studied compared with standardized species, and finally stablish local ecotoxicological protocols involving native species (Encina et al, 2017a, b).…”

Crustáceos acuáticos en arroyo Maquehue.

“…El presente estudio consistió en colecta de crustáceos bentónicos usando lances con una malla surber de 50 * 50 cm, en los meses de abril y mayo de 2016, el material se identificó en base a las descripciones de Domínguez & Fernández (2009) Los presentes resultados concuerdan con reportes para la literatura para ríos de la región (Correa-Araneda et al, 2010a,b;Encina et al, 2017;Vega et al, 2017), donde es posible encontrar ambas especies en ambientes poco contaminados, si bien la literatura menciona la presencia de Aegla de preferencia en zonas de río con baja intervención antrópica. Por otro lado, la presencia de S. spinifrons en bajas abundancias concordaría con reportes de la literatura que indican que esta especie presenta amenazas en cuanto a sus abundancias por explotación, así como contaminación de los hábitats (Jara et al, 2006).…”