Runoff and the longitudinal distribution of macroinvertebrates in a glacier‐fed stream: implications for the effects of global warming

作者：Dean Jacobsen, Sophie Cauvy‐Fraunié, Patricio Andino, Rodrigo Espinosa, Daniela Cueva, Olivier Dangles · 发表于：Freshwater Biology · 年份：2014 · DOI：10.1111/fwb.12405 · 被引用次数：64 · 研究领域：Freshwater macroinvertebrate diversity and ecology、Fish Ecology and Management Studies、Hydrology and Watershed Management Studies

Summary The downstream pattern in benthic macroinvertebrate assemblages along glacier‐fed streams is a result of decreasing glacial influence on environmental conditions. However, meltwater run‐off shows temporal variation, reflected in differences in, for example, temperature, conductivity and turbidity. Consequently, depending on their run‐off patterns, comparable environmental conditions may occur at different distances along glacier‐fed streams. Our aim was to assess whether short‐term variations in glacial run‐off were reflected by changes in longitudinal distribution patterns of macroinvertebrates along a glacier‐fed stream in the E cuadorian A ndes. We measured environmental parameters, obtained continuous gauging data, measured macroinvertebrate drift rate with an hourly resolution during glacial floods and sampled benthic macroinvertebrates c . 3‐monthly for 30 months at three sites at varying distances (0.1–4.3 km) from the glacier. For each sampling date, we fitted logarithmic equations to plots of taxon richness versus distance from the glacier, calculated similarity in assemblage composition between sites and calculated weighted averages of mid‐points of taxon distributions. These data were analysed in relation to mean maximum flow over the 45 days prior to sampling. Mean conductivity and temperature increased while turbidity decreased downstream. During glacial afternoon floods, conductivity decreased while temperature and turbidity increased. High flow moved ma...