HR: 11:30h
AN: B52A-05    [Abstracts]
TI: Changes in Salmon Spawning Habitat Distributions Following Rapid and Gradual Channel Adjustments in the Cedar River, Washington
AU: * Timm, R K
EM: raytimm@u.washington.edu
AF: University of Washington School of Aquatic and Fishery Sciences, 1122 N. E. Boat Street Box 355020, Seattle, WA 98195
AU: Wissmar, R C
EM: wissmar@u.washington.edu
AF: University of Washington School of Aquatic and Fishery Sciences, 1122 N. E. Boat Street Box 355020, Seattle, WA 98195
AU: Berge, H
EM: Hans.Berge@metrokc.gov
AF: King County Department of Natural Resources, 201 S. Jackson Street, Seattle, WA 98104-3855
AU: Foley, S
EM: foleysrf@dfw.gov
AF: Washington Department of Fish and Wildlife, 16018 Mill Creek Boulevard, Mill Creek, WA 98102-1066
AB: Anthropogenic controls on rivers such as dams, hardened banks, and land uses limit the interactions between main river channel and floodplain ecosystems and contribute to decreased habitat diversity. These system controls dampen the frequency and magnitude of natural disturbances that contibute to physical habitat structure and variability. Under natural and altered disturbance regimes river systems are expected to exhibit resiliency. However, in some cases, disturbances cause fluctuations in the trajectory of the mean system state that can have implications for river recovery in the short- and long-term by changing the spatial and temporal dimensions of available habitat relative to specific biological requirements. Historic and contemporary salmon spawning data are analyzed in the context of changing disturbance regimes in the Cedar River, Washington. Historic data are presented for active channel conditions and spawning fish distributions. Contemporary data are presented for an intensively studied reach that received a landslide that deposited approximately 50,000 m3 of sediment in the main channel, temporarily damming the river. Biologically, the spatio-temporal spawning distributions of Chinook (Oncorhynchus tshawytcha) and sockeye (O. nerka) salmon responded to modifications of physical habitat.
DE: 1800 HYDROLOGY
DE: 1803 Anthropogenic effects
DE: 1815 Erosion and sedimentation
DE: 1860 Runoff and streamflow
SC: Biogeosciences [B]
MN: 2005 Joint Assembly