Scientific Investigations Report 2006–5101–D
U.S. GEOLOGICAL SURVEY
Scientific Investigations Report 2006–5101–D
Table 16. Correlations of fish metrics and nonmetric dimensional scaling axis 1 ordination scores with environmental variables, Willamette River basin and surrounding area, Oregon and Washington.
[See appendix A for definitions of environmental variables. Correlation coefficients were considered strong when absolute value ≥ 0.66 (bolded and shaded) and moderate when 0.66 > rho ≥ 0.50 (bolded). Abbreviations: DO, dissolved oxygen; TEQ, toxic equivalent index; SPMD, semipermeable membrane device; TN, total nitrogen; TP, total phosphorus; mg/L, milligram per liter. Symbols: >, greater than]
| Environmental variables | FISH Index |
Percent salmonids |
FISH nMDS Axis1 |
|---|---|---|---|
| Urban indicator metrics | |||
| Urban intensity index (UII) | -0.68 | 0.62 | -0.76 |
| Percent impervious surface | -.63 | .57 | -.69 |
| POPDEN00 | -.68 | .63 | -.75 |
| Percent urban + agriculture | -.56 | .49 | -.68 |
| ROADDEN | -.57 | .54 | -.69 |
| Hydrologic variation metrics | |||
| Number of falling events > 5×median (PeriodF5) | -0.55 | 0.56 | -0.72 |
| Number of falling events > 9×median (PeriodF9) | -.62 | .53 | -.63 |
| Number of rising events > 5×median (PeriodR5) | -.48 | .48 | -.66 |
| Richards-Baker Flashiness Index (Rb-flash) | -.53 | .53 | -.58 |
| Habitat metrics | |||
| Mean embeddedness (riffle and runs) | -0.64 | 0.58 | -0.49 |
| Mean width/depth ratio (riffle and runs) | .61 | -.53 | .37 |
| Percent riffle habitat | .63 | -.78 | .67 |
| Mean habitat heterogeneity | -.50 | .53 | -.53 |
| Water temperature metrics | |||
| Seven day average temperature | -0.15 | 0.26 | -0.52 |
| Minimum temperature (95th percentile) | -.50 | .60 | -.67 |
| Water-chemistry variables | |||
| Summer dissolved oxygen (mg/L) | 0.70 | -0.81 | 0.77 |
| Dissolved organic carbon | -.68 | .66 | -.74 |
| Specific conductance | -.74 | .60 | -.53 |
| Sulfate concentration | -.69 | .48 | -.50 |
| Sum of total insecticides (TN) | -.59 | .46 | -.69 |
| Sum of total pesticides (TP) | -.52 | .43 | -.70 |
| TEQ (SPMD) | -.69 | .70 | .74 |
U.S. Department of the Interior | U.S. Geological Survey
URL: https://pubs.usgs.gov/sir/2006/5101-D
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