Altitudinal and temporal variability of four macroinvertebrate communities in Andean streams, Sangay National Park, Ecuador

Resumo

Aquatic invertebrates are important indicators of water quality, however we need to better understand natural rhythms in order to adequately interpret macroinvertebrate data. Here we present intra-annual variation of four dominant macroinvertebrate families: Baetidae, Hyalellidae, Elmidae and Chironomidae, in high-altitude streams in central Ecuador. Additional analysis using the Kruskal-Wallis and Mann-Whitney tests show that altitude and therefore, vegetation, are important factors when analyzing macroinvertebrate distribution. We sampled 40 sites between January and December 2011 within Achupallas parish, which lies partially within Sangay National Park. The four aforementioned dominant families were most abundant in February/March and in September, with a pronounced midyear minimum. Life cycles and flow regimes play an important role in forming this pattern, but effects of altitude need be considered.