The endangered Fender's blue butterfly in Oregon's Willamette Valley.
Fender's Blue Butterfly The endangered Fender's blue butterfly in Oregon's Willamette Valley. © Matthew Benotsch/The Nature Conservancy

The ecologically richest remnant of native wet prairie in the southern Willamette Valley.

Why You Should Visit
Protected as part of a local partnership that balances development with conservation, Willow Creek's native grasslands, ash woodlands and perennial streams provide the best remaining example of native wet prairie habitats in the southern Willamette Valley.

More than 200 native plant, 100 bird and 25 butterfly species have been recorded on the preserve.

South of West 18th Avenue, in West Eugene

519 acres

Why the Conservancy Selected This Site  

The Nature Conservancy has protected and managed portions of Willow Creek under lease agreements with private landowners since 1981. Willow Creek is part of the West Eugene Wetlands, an area protected through a unique partnership between local, state and federal agencies, the local community and The Nature Conservancy.

What the Conservancy Has Done/Is Doing
In the 1990s, the Conservancy began purchasing additional Willow Creek properties and received gifts of property. In 1995, the Bonneville Power Administration purchased a conservation easement over the property as part of the agency's wildlife habitat mitigation program.

Prescribed fire was reintroduced to Willow Creek in 1986, with assistance from the Oregon Department of Forestry. Periodic burning has reduced the encroachment of trees and shrubs into prairie habitats. It also benefits native prairie plants adapted to periodic fire, such as Bradshaw's lomatium, which has increased by 50 percent in burned areas.

Teams of volunteers regularly help control invasive, non-native species, including Scots broom and Himalayan blackberry. Ecologists are monitoring water quality and conducting research on native reptiles, amphibians, butterflies, native plants and other elements of Willamette Valley prairie ecology.

What to See: Plants

The wet prairie on the preserve is characterized by tufted hairgrass and provides habitat for the Willamette Valley daisy, white-topped aster and Bradshaw's lomatium.

What to See: Animals

Fender's blue butterfly, thought to be extinct until rediscovered in 1989, is found in an upland prairie remnant in association with the rare Kincaid's lupine, the primary food source of the butterfly's larvae. The preserve also hosts the western pond turtle, a reclusive species once common in the Willamette Valley but now rare.

The preserve is best visited in late spring and in summer; it is very wet in winter and early spring and more subject to visitor impacts during these times.

Please observe the following guidelines while hiking:

  • Stay on the trail. Don't collect plants, insects or other species or disturb soil, rocks, artifacts or scientific research markers.
  • No dogs. Preserves harbor ground-nesting birds and other wildlife that are extremely sensitive to disturbance.
  • No bicycles or motorized vehicles. Native plants and research sites are easily trampled.
  • No hunting, camping or campfires.
  • For groups of 10 or more, please contact us before visiting a preserve (a volunteer naturalist guide may be available).
  • Please bring a bag and carry out any trash you find.
  • Please report to us any problems you observe (e.g., camping, plant removal, hunting, off-road vehicle damage, etc).