Download the Willamette Valley-Puget Trough-Georgia Basin Ecoregional Assessment
The Willamette Valley-Puget Trough-Georgia Basin ecoregion is a long ribbon of broad valley lowlands and inland sea flanked by the rugged Cascade and coastal mountain ranges of British Columbia, Washington, and Oregon. It encompasses some 5,550,000 ha of Pacific inlet, coastal lowlands, islands, and intermontane lowland, and extends from the Sunshine Coast and eastern lowland of Vancouver Island along Georgia Strait, south through Puget Sound and the extensive plains and river floodplains in the Willamette Valley.
Although the ecoregion's elevation (land portion) averages 445 feet (maximum 4,203 feet), the effect of the adjacent mountains, ocean intrusions, and glaciation in the region's northern two-thirds have caused dramatic localized differences in climate, soils, and geology. The ecoregion contains over 10,000 miles of streams and rivers, including the middle reaches of a number of major (third order or larger) rivers whose headwaters lie in the mountains of adjacent ecoregions.
From distinctive combinations of these factors spring an array of ecological communities ranging from coniferous forests to open prairies, rocky balds, and oak
savannas. The marine and estuarine environments of British Columbia and Washington add even greater diversity of communities and species.
Characteristic wildlife includes Raccoon, Sea Otter, Black-tailed Deer, and Harbour Seal. There is a rich diversity of birds including Turkey Vulture, Bald Eagle, and Blue Grouse. Willamette Valley is the sole wintering area of the Dusky Canada Goose.
Ninety percent of the terrestrial portion of the ecoregion is either private or tribal land. Nearly three-quarters of the populations of British Columbia, Washington, and Oregon live within this ecoregion. Human development of the ecoregion has been rapid since the 1850s and continues today, with a 62% growth in population from 1950-2000 and a 16% growth in the past 10 years (U.S. Census Bureau 2000; StatCan 2002; Risser et al. 2000).
Habitat conversion for human uses has been widespread, reflecting the accessibility, rich natural resources, and economic potential of virtually the entire ecoregion. Today, over 40% of the ecoregion has been converted to urban or tilled agricultural uses, and most of the remainder is in production forestry, making this the most highly developed of the Pacific Northwest ecoregions.
The Willamette Valley-Puget Trough-Georgia Basin Ecoregional Assessment is the product of a partnership initiated in 1998 to identify priority conservation areas in this ecoregion. The Nature Conservancy of Canada (NCC), The Nature Conservancy (TNC), and the Washington Department of Fish and Wildlife (WDFW) are the primary partners in this project. The Oregon Natural Heritage Information Center (ONHIC), the Natural Heritage Program (WNHP) and Nearshore Habitat Program of the Washington Department of Natural Resources (WDNR), and the British Columbia Conservation Data Centre (CDC) were major contributors of technical expertise and data. The project has also benefited from the participation of many other scientists and conservation experts as team members and reviewers.