1. Department of Biology and Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado 80523 USA
2. Department of Civil and Environmental Engineering and Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado 80523 USA
3. Center for Ecohydraulics Research, University of Idaho, Boise, Idaho 83702 USA
4. US Geological Survey, 12201 Sunrise Valley Drive, MS 413, Reston, Virginia 20192 USA