Does rapid glacial recession affect feeding habits of alpine stream insects?

1. Glacial retreat, accompanied by shifts in riparian vegetation and glacier meltwater inputs, alters the energy supply and trophic structure of alpine stream food webs. Our goal in this study was to enhance understanding of dietary niches of macroinvertebrates inhabiting different alpine streams with contrasting glacial and non-glacial (groundwater, precipitation, snowmelt) water inputs in conjunction with seasonal and habitat-specific variation in basal resource availability.  

2. We measured a range of stream physico-chemical attributes as well as carbon and nitrogen isotopes (δ13C, δ15N) of macroinvertebrates and primary food sources at seven sites across seasons within a Swiss glaciated catchment (Val Roseg) undergoing rapid glacial retreat (1-2 km between years 1997–2014). Sampling sites corresponded to streams used in a previous (1997/1998) study within the same alpine catchment.

3. Physico-chemical attributes showed wide variation in environmental conditions across streams...