Abstract

GARCIA-RIOS, Raúl; MOI, Dieison A  and  PELAEZ, Oscar E. Effects of an altitudinal gradient on benthic macroinvertebrate assemblages in two hydrological periods in a Neotropical Andean river. Ecol. austral [online]. 2020, vol.30, n.1, pp.33-44. ISSN 1667-782X.

The altitudinal gradient and the hydrological dynamics affect the establishment and distribution of organisms in Andean rivers. Benthic macroinvertebrates, an essential component of lotic ecosystems, are useful to assess the influence of the altitudinal gradient and changes in environmental characteristics. We analyzed the effects of altitudinal gradient on benthic macroinvertebrates assemblages in the Chillón River (Lima, Perú), and tested two hypotheses: 1) taxa richness decreases with increasing altitude, while dominance increases, and 2) altitude is the primary driver of variation in community composition. We found 47 taxa, being the class Insecta (Arthropoda) the richest and the densest in both hydrological periods. Taxa richness had a negative linear relation with altitude, while dominance had a positive linear relation. The RDA showed that communities varied along the altitudinal gradient. Our results showed that altitude is the main driver of variation in taxa composition; however, more studies must be carried out to understand what factors are essential in organism’s distribution and how they operate in Andean lotic ecosystems.

Keywords : Species distribution; High-altitude rivers; Elevational patterns; Freshwater invertebrates.

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