Characterization of the Hydraulic Habitat of Brachycentrus occidentalis, a Filter-Feeding Caddisfly
| Autor: | Rosemary J. Mackay, Sharron H. Wetmore, Robert W. Newbury |
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| Rok vydání: | 1990 |
| Předmět: | |
| Zdroj: | Journal of the North American Benthological Society. 9:157-169 |
| ISSN: | 1937-237X 0887-3593 |
| Popis: | Local velocity and flow profiles (50 cm in length) were measured in accelerating transitional-velocity zones in two 20-40-m long contrasting reaches of cobble and shale substrate in Wilson Creek, Manitoba, to characterize the observed hydraulic habitat of individual Brachycentrus occidentalis larvae (instars IV and V). Both instars in the cobble reach were in local habitats with faster water-column velocities, shallower depths, steeper water-surface slopes, and higher Froude numbers than randomly available locations in similar transitional-velocity zones. Values for hydraulic variables were mostly higher for instar IV habitat. Random conditions in the shale reach differed from those in the cobble reach, but differences between larval (instar V) habitat and random locations were again significant. Although larvae in the shale reach were at slower velocities and shallower depths than larvae in the cobble reach, they selected identical hydraulic regimes in terms of water-surface slope and Froude number. At b... |
| Databáze: | OpenAIRE |
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