Area includes the Tualatin River and floodplain, numerous tributaries, and associated uplands from the confluence with the Willamette River upstream to Patton Valley, west of Gaston.
COA ID: 064
The Willamette Valley ecoregion is bounded on the west by the Coast Range and on the east by the Cascade Range. This long mostly level alluvial plain has some scattered areas of low basalt, and contrasts with productive farmland and large urban areas. It has the fastest-growing human population in the state resulting in challenges due to land-use changes.
Grasslands include a variety of upland grass-dominated habitats, such as upland prairies, coastal bluffs, and montane grasslands.
Natural lakes are relatively large bodies of freshwater surrounded by land. For the purposes of the Conservation Strategy, natural lakes are defined as standing water bodies larger than 20 acres, including some seasonal lakes.
Oak woodlands are characterized by an open canopy dominated by Oregon white oak.
Flowing Water and Riparian Habitats
Flowing Water and Riparian Habitats include all naturally occurring flowing freshwater streams and rivers throughout Oregon as well as the adjacent riparian habitat.
Wetlands are covered with water during all or part of the year. Permanently wet habitats include backwater sloughs, oxbow lakes, and marshes, while seasonally wet habitats include seasonal ponds, vernal pools, and wet prairies.
Acorn Woodpecker (Observed)
California Floater Freshwater Mussel (Observed)
California Myotis (Observed)
Chipping Sparrow (Observed)
Clouded Salamander (Modeled Habitat)
Coastal Cutthroat Trout (Documented)
Oncorhynchus clarki clarki
Columbia Torrent Salamander (Modeled Habitat)
Common Nighthawk (Observed)
Fringed Myotis (Modeled Habitat)
Hoary Bat (Modeled Habitat)
Lewis’s Woodpecker (Observed)
Northern Red-legged Frog (Observed)
Nelson’s Checkermallow (Observed)
Northern Spotted Owl (Observed)
Strix occidentalis caurina
Olive-sided Flycatcher (Observed)
Oregon Slender Salamander (Modeled Habitat)
Oregon Vesper Sparrow (Observed)
Pooecetes gramineus affinis
Purple Martin (Observed)
Progne subis arboricola
Short-eared Owl (Observed)
Asio flammeus flammeus
Silver-haired Bat (Modeled Habitat)
Townsend’s Big-eared Bat (Observed)
Western Bluebird (Observed)
Western Gray Squirrel (Observed)
Western Meadowlark (Observed)
Western Painted Turtle (Observed)
Chrysemys picta bellii
Western Pond Turtle (Observed)
Western Ridged Mussel (Observed)
White Rock Larkspur (Observed)
Willow Flycatcher (Observed)
Winged Floater Freshwater Mussel (Observed)
Yellow-breasted Chat (Observed)
Icteria virens auricollis