Aquatic Sciences Meeting, Albuquerque 2001

SS15 Biomechanics: Making the Connection Between Physics and Biology at the Organismal Level (Disciplinary Connections)

Date: Wednesday, February 14, 2001, Time: 2:15:00 PM

Location: Mesilla

Hoover, T, M, University of Northern British Columbia, Prince George, Canada, trenthoover@hotmail.com

Ackerman, J, D, University of Northern British Columbia, Prince George, Canada, ackerman@unbc.ca

HYDRAULIC HABITAT PREFERENCES OF THE TORRENTIAL MAYFLY EPEORUS DECEPTIVUS (HEPTAGENIIDAE): THE ECOLOGICAL IMPORTANCE OF NEAR-BED FLOWS

The hydraulic habitat of the torrential mayfly Epeorus deceptivus was characterised by measuring the fine-scale distribution of a number of hydrodynamic variables (e.g. near-bed velocities, wall shear stress) over the surface of 5 experimentally-deployed and 3 naturally-occurring stones in a third order mountain stream. Generally, wall shear stress and near-bed velocity were found to increase from the front to the rear of each stone. In addition, day- and nighttime distributions of E. deceptivus were recorded and related to shear stress, periphyton biomass, and substrate characteristics (i.e. stone roughness, topography). During the daytime, larvae preferred areas of the stone surface with high shear stress; during the nighttime, larvae preferred areas relatively high on the stone surface with attached boundary layer flows. Periphyton density was significantly related to stone surface roughness and stone surface topography. A short-term stone reversal experiment suggests that hydrodynamic factors, rather than food (periphyton) availability, influence the distribution of E. deceptivus larvae. The results of this study demonstrate the importance of hydrodynamics in structuring the benthic community in high-velocity stream habitats.

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Aquatic Sciences Meeting, Albuquerque 2001

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