2022 Early Hearing Detection & Intervention Virtual Conference

March 13 - 15, 2022

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5/23/2019  |   11:00 AM - 11:15 AM   |  NET-SPINNING CADDISFLIES REDUCE STREAMBED HYDRAULIC CONDUCTIVITY   |  251 DE

NET-SPINNING CADDISFLIES REDUCE STREAMBED HYDRAULIC CONDUCTIVITY

The streambed is an ecotone between surface waters and underlying hyporheic systems. Identifying the controls that modulate advective flow through this ecotone is critical to understanding the movement of energy and matter in streams. Hydropsychids (net-spinning caddisflies) are aquatic ecosystem engineers that influence streambed cohesion, yet evidence of direct influence on hydrologic processes is lacking. Through a novel permeameter experiment, we demonstrate how net-spinning caddisfly colonization of the streambed interstitia at moderate densities (2000 m-2) can reduce the saturated vertical hydraulic conductivity (Kv) by up to 60% in course sand and gravels (1.4mm – 22mm). Permeameter cores incubated in stream water occupied by caddisflies showed reduced Kv relative to those similarly incubated without caddisflies. Our research shows that the ubiquitous and numerous net-spinning caddisflies are likely to modulate the exchange of channel and hyporheic water by constructing nets in open pore spaces, increasing flow resistance and decreasing flow velocities. These results suggest that caddisfly induced reductions in pore flow may increase the contact time between water and sediments and therefore alter biogeochemical processes in the hyporheic zone.

  • Hyporheic
  • Invertebrate
  • Mesocosm

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Presenters/Authors

Michael MacDonald (), Montana State University, macdonald.mik@gmail.com;


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Geoffrey Poole (), Montana State University, Montana Institute on Ecosystems, gpoole@montana.edu ;


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Lindsey Albertson (), Montana State University , lindsey.albertson@montana.edu;


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