MODENUTTI Beatriz Estela
Seasonal variability in glacial influence affects macroinvertebrate assemblages in North-Andean Patagonian glacier-fed streams
MARTYNIUK, NICOLÁS; MODENUTTI, BEATRIZ; BALSEIRO, ESTEBAN G.
Taylor and Francis
Año: 2019 p. 1 - 1
Macroinvertebrate communities of glacial streams are aﬀected by melting mountain glaciers, which in turn are inﬂuenced by landscape and local and global climate change. We analyzed macroinvertebrate communities in 2 North-Andean Patagonian glacier-fed streams. The signiﬁcant diﬀerence in glacial inﬂuence between the 2 streams was due to diﬀerences in glacier ﬂow velocity and to the presence of a proglacial lake in one of the streams. Our main aim was to analyze whether temporal variations in physical and chemical parameters of meltwater produced shifts in macroinvertebrate taxon richness and community composition. We applied the glaciality index (GI) to consider the combined eﬀect of suspended solids, water temperature, conductivity, and streambed stability. On each stream we established one sampling station; we sampled during the melting season (spring?summer) of 3 consecutive years on 12 occasions. Macroinvertebrate taxon richness, diversity, and evenness increased as glacial inﬂuence decreased. Scrapers were the dominant functional feeding group in the stream with the lower glacial inﬂuence while detritivores-gathers dominated under high glacial inﬂuence. We further analyzed how temporal changes in the GI aﬀected compositional diﬀerences among communities using Bray-Curtis dissimilarities. Under a stable GI, communities showed no substantial compositional changes (low Bray-Curtis), whereas under change in glacial inﬂuence (ΔGI ≠ 0) the communities decreased in similarity.