Longitudinal variation of macroinvertebrate assemblages in Icelandic arctic glacier-fed and snow-fed streams: changes and their environmental drivers – a comparison after 26 years

• Applicant: Professor Dr. Peter Chifflard, since 11/2023
• Subject Area: Hydrogeology, Hydrology, Limnology, Urban Water Management, Water Chemistry, Integrated Water Resources Management
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 510589285

Climate-induced retreat of glaciers will affect the macroinvertebrate composition in glacier‐fed rivers and lead to an increase in α-diversity and abundance as well as to an upward migration of downstream macroinvertebrates. In Arctic regions, where climate change is expected to cause major environmental changes, snow is becoming increasingly important for aquatic ecosystems, and the influence of glacier meltwater is declining. The consequences for macroinvertebrate composition are still largely unresolved, mainly because long-term studies in Arctic regions are also lacking. Therefore, this research project will investigate temporal changes in macroinvertebrates along an Arctic glacier-fed river and a snow-fed river on the basis of Gíslason et al. (2001) who mapped macroinvertebrate, hydrophysical and -chemical parameters in 1996 and 1997 along the arctic rivers Vestari- and Austari-Jökulsá River. Since these first investigations the hydrological and climatic conditions have changed significantly. As a repetitive investigation the abiotic variables electrical conductivity, water temperate, -level, DOC (conc., absorbance, fluoresce.), stable isotopes, dissolved silica, nutrients (PO4, NO3, NO2, and NH4), ions (Ca, Mg, Na, K), chlorophyll α and suspended sediment as well as macroinvertebrates will be investigated at the same locations (21) as in 1996 and 1997 during 6 seasonal sampling campaigns (spring, summer, autumn) over a time period of two years. For future monitoring of fauna in glacial rivers, the innovative and non-invasive method of environmental DNA-metabarcoding is being tested and further developed. This approach has already been successfully applied in other aquatic ecosystems, but not yet in glacier-fed rivers. A range of statistical techniques (e.g., one-way/two-way ANOVA) will be applied, to identify differences in longitudinal changes of macroinvertebrate assemblages between the several investigations and to detect environmental drivers. Different water sources and their relative runoff contribution will be identified by end-member mixing analysis, whereby the impact of climate change induced variations of water sources on macroinvertebrates can be assessed. This intensive cross-scale study of the hydrobiological and biogeochemical properties of two Arctic streams with different hydrology and their spatial and temporal dynamics will close the knowledge gap regarding the long-term change of longitudinal variation of macroinvertebrate communities in arctic glacier-fed streams.

• DFG Programme: Research Grants
• International Connection: Iceland
• Cooperation Partners: Gísli Már Gíslason; Snaebjörn Pálsson
• Ehemaliger Antragsteller: Dr. Martin Reiss, until 11/2023