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Willamette Valley

Historically one of the dominant habitat types in the Willamette Valley, wetlands have been one of the biggest casualties of the ecoregion's urban and agricultural development. An estimated 87 percent of the region's wetland and riparian habitats have been converted to non-native habitats. Most of the valley's seasonal wetlands have been drained, and flood control modifications have left the Willamette River largely disconnected from the braided channels, oxbows and sloughs that marked most of its historic floodplain. Only a few small fragments remain of the valley's formerly abundant wet prairies, but they harbor an impressive number of native species. The Nature Conservancy's 330-acre Willow Creek Preserve supports more than 200 species of native plants, 100 bird species and 25 species of butterfly. Remaining areas with large blocks of wetland habitats are critical to the region's wildlife populations, particularly migratory birds. More than 30 species of ducks, geese, and swans, and a diverse assemblage of shorebirds and wading birds use the wetlands in the valley on a regular basis. Recent counts have shown use by more than 300,000 wintering waterfowl, including seven subspecies of Canada geese in winter. Agricultural fields, mudflats, and the borders of freshwater wetlands support up to 10,000 wintering killdeer, a regionally declining species. Remnant riparian forests, grassland-savanna, and oak woodlands provide important habitat for more than 100 breeding migratory landbird species. The largest blocks of wetlands are found in a chain of state and federal wildlife refuges that extends along the western side of the valley, and in floodplain areas along the Willamette River and its major tributaries.

For more information, see the Joint Venture’s Willamette Valley plan.