Response of stream macroinvertebrates in flow refugia and high-scour areas to a series of floods: a reciprocal replacement study

Abstract

AbstractDisturbances from flooding are a dominant feature of the habitat template in streams. Frequent floods created by recreational releases (1–2 d between releases/floods) from Abanakee Dam in the Adirondack Mountains, USA, result in a static mosaic of scoured patches in areas of high shear stress (low diatom densities) and mats of algae in areas of low shear stress (refugia); this pattern is different from the shifting mosaic of patches more typical of streams recovering from floods. Predictable, recreational release floods and similar bed size particle distributions in this stream enabled us to use a reciprocal replacement experiment to examine macroinvertebrate community responses in high scour and flow refugia areas without the confounding variable of different substrata. Trays of substrata were embedded in both high shear stress (HSS) and low shear stress (LSS) areas. Half of the trays from each area were then reciprocally exchanged while resident trays remained in their original positions. After ...