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...1. 冰川退缩伴随河岸植被变化与冰川融水输入，改变了高山溪流食物网的能量供给与营养结构。本研究旨在深化对栖息于不同高山溪流的大型无脊椎动物（macroinvertebrates）摄食生态位（dietary niches）的认识，这些溪流的水源存在冰川与非冰川（地下水、降水、融雪）输入的差异，同时结合基础食物资源可获得性的季节与生境特异性变化。 2. 我们在正经历快速冰川退缩（1997至2014年间退缩幅度达1-2千米）的瑞士冰川流域（罗斯格谷（Val Roseg））内，于多个季节在7个采样点测定了一系列溪流理化属性（physico-chemical attributes），以及大型无脊椎动物与初级食物源的碳、氮同位素（δ¹³C、δ¹⁵N）比值。本次采样点位与此前同一高山流域内一项1997/1998年研究中使用的溪流点位一致。 3. 理化属性结果显示，不同溪流间的环境条件存在广泛差异……