Scientific Investigations Report 2006–5101–D
U.S. GEOLOGICAL SURVEY
Scientific Investigations Report 2006–5101–D
Figure 17. Relation between urban intensity index (UII) and number of benthic macroinvertebrate taxa (richness) in the Ephemeroptera, Plecoptera, and Trichoptera orders (EPT), Willamette River basin and surrounding area, Oregon and Washington.