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Cool tributary 26°C

Coldwater refugia in high desert streams. Thalweg 27°C. Cool tributary 26°C. Subsurface inputs 25°C. Rainbow trout ( Oncorhynchus mykiss ). Water temperature 25°C. Microhabitat coldwater refuge. Adult chinook salmon ( Oncorhynchus tshawytscha ). A bird’s-eye view of temperature.

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Cool tributary 26°C

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  1. Coldwater refugia in high desert streams Thalweg 27°C Cool tributary 26°C Subsurface inputs 25°C

  2. Rainbow trout (Oncorhynchus mykiss) Water temperature 25°C

  3. Microhabitat coldwater refuge Adult chinook salmon (Oncorhynchus tshawytscha)

  4. A bird’s-eye view of temperature

  5. Airborne Thermal Remote Sensing Middle Fork John Day River Main channelTributary confluenceGround-truth (Torgersen et al. 2001)

  6. Reach-level associations (Torgersen et al. 1999)

  7. Spatial heterogeneity in riverscapes (Fausch, Torgersen, Baxter, and Li 2002)

  8. Habitat heterogeneity at two spatial scales Larval Pacific lamprey Benthic sampling (1 m x 1 m). (Torgersen and Close 2004)

  9. Site selection and nested design

  10. Distribution of larvae among sites Water depth (+) Shade (-)

  11. Spatial variation within sites Site 29Rkm 9n = 232high density NOT water depth Water velocity (-) % fines in substrate (+)

  12. Scaling of fish assemblages and habitat relationships

  13. Multivariateanalysis ofcommunitystructure Middle Fork John Day RiverWARM

  14. Community structure in aCOOL stream North Fork John Day River

  15. Scale-dependent relationships Effects of spatial extent on ecological relationships • Thermal crossover between warm- and coldwater species 20-22°C (Torgersen et al. 2006)

  16. Review of concepts 1. Identifying the “correct” scale. Until we examine a range of scales, we are just guessing.

  17. Review of concepts 2. Predictor variables change depending on scale of analysis. Collect data and develop models at more than one scale.

  18. Review of concepts 3. Spatial extent is as important as resolution. Maintain flexibility across multiple scales (e.g., spatially continuous data).

  19. Fausch, K. D., C. E. Torgersen, C. V. Baxter, and H. W. Li. 2002. Landscapes to riverscapes: Bridging the gap between research and conservation of stream fishes. BioScience 52:483-498. Torgersen, C. E., D. M. Price, H. W. Li, and B. A. McIntosh. 1999. Multiscale thermal refugia and stream habitat associations of chinook salmon in northeastern Oregon. Ecological Applications 9:301-319. Torgersen, C. E., R. N. Faux, B. A. McIntosh, N. J. Poage, and D. J. Norton. 2001. Airborne thermal remote sensing for water temperature assessment in rivers and streams. Remote Sensing of Environment 76:386-398. Torgersen, C. E., and D. A. Close. 2004. Influence of habitat heterogeneity on the distribution of larval Pacific lamprey (Lampetra tridentata) at two spatial scales. Freshwater Biology 49:614-630. Torgersen, C. E., C. V. Baxter, H. W. Li, and B. A. McIntosh. 2006. Landscape influences on longitudinal patterns of river fishes: Spatially continuous analysis of fish-habitat relationships. Pages 473-492 in R. M. Hughes, L. Wang, and P. W. Seelbach, editors. Landscape influences on stream habitats and biological assemblages. American Fisheries Society, Bethesda, Maryland.

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