Taxon-specific responses to high-flow disturbance in streams:implications for population persistence

Abstract

AbstractThis study examined how the leptophlebiid mayfly Deleatidium spp., the mudsnail Potamopyrgus antipodarum, and stony-cased caddisflies Pycnocentrodes aeris and Hudsonema amabilis, each with different flow habitat preferences and motilities, respond to elevated flows. Our aim was to learn more about how refuge-seeking behavior and life-history traits affect species persistence along the flow disturbance gradient. All taxa responded to incrementally increased flows in a recirculating laboratory flume with layered substrata by moving to deeper, more stable layers. However, snails made the most pronounced shift to protected sublayers. Caddisflies that remained on epibenthic surfaces during high flows laid draglines on surface rocks to effectively resist dislodgment. Very few individuals of any taxon were washed from epibenthic habitats by high flows alone. Simulated flash floods in artificial stream channels revealed that dislodgment was linked to substrate stability and that likelihood to be dislodged...