Spatio-temporal dynamics of macroinvertebrate communities in northeast Greenlandic snowmelt streams.

New publication by Catherine L. Docherty, David M. Hannah, Tenna Riis, Magnus Lund, Jakob Abermann, Alexander M. Milner

2018.10.23 | Peter Schmidt Mikkelsen

Abstract:

 

Future climate change throughout the Arctic is expected to increase channel stability in glacially influenced streams through reduced contributions from glacial meltwater and increases in groundwater. In contrast, predictions for northeast Greenland of increased precipitation for the next 100 years—including winter snowfall—which with warmer air temperature, is expected to increase the size of spring floods in snowmelt streams. Coupled with increased disturbance through frequent summer rainfall events, nivation processes and permafrost degradation will reduce resistance of channel sediments to erosion and thereby decrease channel stability. Decreased channel stability will impact macroinvertebrate abundance and diversity. Five streams sourced by snowpacks of varying extent were studied over 3 summer seasons (2013–2015) to investigate the potential effect of shift in snowmelt regime on macroinvertebrate communities.

Total abundance and taxa richness were significantly higher in streams with small snowpacks, where the chironomid genus Hydrobaenus was the most abundant taxon. Streams with large snowpacks were dominated by the chironomid genus Diamesa. Multivariate ordination models and correlation indicated that macroinvertebrate communities were significantly influenced by channel stability and bed sediment size. Macroinvertebrate abundance was significantly higher in 2013, following low winter snowfall and associated low meltwater inputs to streams, highlighting interannual variability in macroinvertebrate communities.

A shift towards less stable habitats in snowmelt streams will potentially lead to reduced macroinvertebrate abundance and taxa richness, and local extinction of specialized taxa. Thus, snowmelt‐fed streams in northeast Greenland may respond very differently to changing climate compared with streams in parts of the Arctic dominated by glacial meltwater.

 

Ecohydrology, Bind 11, Nr. 7, 1982, 10.2018.https://doi.org/10.1002/eco.1982

Arctic Research Centre