Effect of ecoregion and river type on neotropical Chironomidae (Diptera) from humid mountain to semiarid lowland

Introduction: Chironomidae (Diptera) is the most widespread and abundant aquatic insect family in freshwater ecosystems. Chironomids are considered good indicators of water quality but seldom identified at genus level broad spatial scale studies. Objective: To identify environmental conditions associated with chironomids an altitudinal gradient. Methods: We compared ecoregions, river types, seasons, for neotropical streams rivers (18 sites; 2014-2018; Yungas rainforest Western Chaco dry forest, Argentina). used non-metric multidimensional scaling, dissimilarity, envfit analysis rank-abundance curves. Results: Chironomic “assemblages” matched both ecoregions types. However, presented a better fit species composition. The stenothermal taxa Orthocladiinae were dominant high elevations eurythermal Chironominae lowland rivers. Altitude, temperature conductivity important. Seasonal differences smaller than ecoregional differences. Conclusions: Ecoregions, altitude, correlated chironomid communities.