Cool tributary 26°CCool tributary 26°C

Subsurface inputs 25°CSubsurface inputs 25°C

Coldwater refugia in high desert Coldwater refugia in high desert streamsstreams

Thalweg 27°CThalweg 27°C

Water temperature Water temperature 25°C25°C

Rainbow trout (Rainbow trout (Oncorhynchus mykissOncorhynchus mykiss))

Microhabitat coldwater Microhabitat coldwater refugerefuge

Adult chinook Adult chinook salmon salmon ((Oncorhynchus Oncorhynchus tshawytschatshawytscha))

Extensive fishsurvey

0 100N

OREGON

Columbia R.

Joh

n Grande

Day

R.

STUDY AREASJOHN DAY BASINGRANDE RONDE BASIN

Ron

de R

.

Snake R.

Km

A bird’s-eye view of temperatureA bird’s-eye view of temperature

Airborne Thermal Remote Sensing

Distance upstream (km)

70 80 90 100 110

Tem

pera

ture

(°C

)

20

22

24

26

28

30

32

Springs

5 August 199813:25-13:54Main channel

Tributary confluenceGround-truth

Middle Fork John Day River

(Torgersen et al. 2001)

Reach-level associations

(Torgersen et al. 1999)

Spatial heterogeneity in riverscapes

(Fausch, Torgersen, Baxter, and Li 2002)

Habitat heterogeneity at two Habitat heterogeneity at two spatial scalesspatial scales

Benthic Benthic sampling sampling (1 m x 1 m).(1 m x 1 m).

Larval Pacific Larval Pacific lampreylamprey

(Torgersen and Close 2004)

Site selection and nested Site selection and nested designdesign

Distance upstream (km)

0 10 20 30 40 50 60

Den

sity

(la

rvae

/m2 )

0

5

10

15

20

25

Distribution of larvae among Distribution of larvae among sitessites Water depth

(+)

Shade (-)

Site 29Site 29Rkm 9Rkm 9nn = 232 = 232high densityhigh density

Spatial variation within Spatial variation within sitessites

NOT water depth

Water velocity (-)

% fines in substrate (+)

Scaling of fish assemblages and Scaling of fish assemblages and habitat habitat relationshipsrelationships

MFJD

Distance upstream (km)

60 70 80 90 100 110 120

Axi

s sc

ore

0.04

0.06

0.08

0.10

0.12

0.14Axis 1Axis 2

MultivariateMultivariateanalysis ofanalysis ofcommunitycommunitystructurestructure

Middle Fork John Day River WARM

Community Community structurestructure in a in aCOOLCOOL stream stream

North Fork North Fork John Day RiverJohn Day River

NFJD

Distance upstream (km)

100 110 120 130 140 150 160

Axi

s sc

ore

-1.0

-0.5

0.0

0.5

1.0

Axis 1Axis 2

Scale-dependent Scale-dependent relationshipsrelationships

20 30 40 50

Pea

rso

n's

r

0.1

0.2

0.3

0.4

0.5

0.6

Spatial extent (km)

20 30 40 50 60 70

Pea

rso

n's

r

0.0

0.2

0.4

0.6

0.8

1.0

TemperatureDepthHabitat type

MFJD

NFJD

crossover

crossover

Downstream Upstream

Effects of spatial Effects of spatial extent on extent on ecological ecological relationships relationships

• Thermal Thermal crossover crossover between warm- between warm- and coldwater and coldwater species 20-22°C species 20-22°C

(Torgersen et al. 2006)(Torgersen et al. 2006)

Review of conceptsReview of concepts

1. Identifying the 1. Identifying the “correct” scale.“correct” scale.

Until we examine a Until we examine a range of scales, we are range of scales, we are just guessing.just guessing.

Review of conceptsReview of concepts

2. Predictor variables 2. Predictor variables change depending on change depending on scale of analysis.scale of analysis.

Collect data and Collect data and develop models at more develop models at more than one scale.than one scale.

Review of conceptsReview of concepts

3. Spatial extent is as 3. Spatial extent is as important as resolution.important as resolution.

Maintain flexibility Maintain flexibility across multiple scales across multiple scales (e.g., spatially continuous data).(e.g., spatially continuous data).

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.