Thursday, May 21, 2009 - 10:45 AM
541

Effects of landscape gradients assessed at varying scales on riverine ecosytems

Robert M. Hughes1, Alan T. Herlihy1, and Colleen Burch Johnson2. (1) Fisheries and Wildlife, Oregon State University, 200 SW 35th St., Corvallis, OR 97333, (2) Raytheon, 200 SW 35th St., Corvallis, OR 97333

We sampled 20 sites on each of 6 raftable Oregon & Washington rivers for fish & benthos assemblages and physical & chemical habitat.  The river mainstems sampled ranged from 80-280 km long, and included systems draining humid and xeric catchments.  Results are associated with landscape predictor variables evaluated at local landscape, local riparian, basin, and basin riparian scales.  Depending on the river, initial site scale results show site improvement, site degradation, and no pattern with river kilometer.  Similarly, the importance of various landscape variables and spatial extents vary with river and river position.