The Willamette Valley-Puget Trough-Georgia Basin Ecoregional Assessment provides an approximation of the most important places for conserving native species and ecosystems in the most highly developed region of the Pacific Northwest in the United States and British Columbia, Canada.
The region includes the fertile lowlands of Oregon’s Willamette Valley, Washington’s Puget Trough, British Columbia’s Georgia Basin, and the nearshore marine waters of Puget Sound and the Strait of Georgia.
The assessment is intended to help conservation agencies, planners and organizations direct resources to support the region’s biodiversity. The assessment describes a portfolio of priority conservation areas that are of exceptional biological value and are the most likely places for conservation to succeed based on current conditions, land use, and other factors.
This assessment is a guide and resource for planners and decision-makers, and has no regulatory authority.
Mission and Objectives
The purpose of the Willamette Valley-Puget Trough-Georgia Basin Ecoregional Assessment is to identify priority areas for conserving the biodiversity of the Willamette Valley-Puget Trough-Georgia Basin ecoregion.
The assessment is a resource and guide for planners and others interested in the status or conservation of the biological diversity of this ecoregion.
Lead Organizations
Key Parties
Federal-U.S.
State
Provincial
The Willamette Valley-Puget Trough-Georgia Basin Ecoregional Assessment was developed through the following process:
Technical Teams
Five expert technical teams collaborated on a series of analyses based on methods developed by The Nature Conservancy and other scientists. Three teams covered the terrestrial environment’s plants, animals and ecological systems. A fourth assessed the nearshore marine environment within the Puget Sound and Georgia Strait. A fifth team studied the ecoregion’s freshwater systems.
Core Team
All the technical teams were coordinated and directed by an oversight group called the Core Team, made up of technical team leads and other scientists and conservation professionals from British Columbia, Washington, and Oregon. Staff from The Nature Conservancy in Washington led data compilation, analysis, and portfolio development for terrestrial, marine, and freshwater conservation targets.
The Willamette Valley-Puget Trough-Georgia Basin Ecoregional Assessment was produced by a partnership initiated in 1998 to identify priority conservation areas in this ecoregion.
The assessment was proposed in a Charter Agreement of the Willamette Valley-Puget Trough-Georgia Basin among The Nature Conservancy, The Nature Conservancy of Canada, and the Washington Department of Fish and Wildlife.
The priority-setting plan was developed to balance natural resource demands with the conservation of natural heritage while creating the fewest conflicts with the legitimate use of natural resources.
Increasing populations and associated land use changes motivated the effort.
The Ecosystem
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.
The ecoregion encompasses 21,431 square miles of Pacific inlet, coastal lowlands, islands, and intermontane lowland. It includes the Sunshine Coast and eastern lowland of Vancouver Island in Canada along the Georgia Strait. It also includes the region to the south through Puget Sound and the extensive plains and river floodplains in the Willamette Valley.
The average elevation of the ecoregion is 445 feet above sea level. But the presence of mountains, ocean intrusions and glaciation cause dramatic and localized differences in climate, soils and geology. Distinctive combinations of these factors lead to an array of ecological communities such as coniferous forests, open prairies, rocky balds, and oak savannas.
The ecoregion includes nearshore areas, namely the Puget Sound and Strait of Georgia, which feature a variety of deepwater and nearshore habitats. These habitats include coastal lagoons, kelp and seagrass beds, rocky shores, sandy beaches and spits, and salt marsh wetlands. Steep underwater slopes result in narrow strips of shallow water habitats near the shore. Puget Sound is home to marine mammals including harbor seals, orcas, porpoises, and California sea lions.
Threats
Threats to the ecoregion include:
Development of a Priority-Setting Plan
The Willamette Valley-Puget Trough-Georgia Basin Ecoregional Assessment can be used by planners and conservation organizations to prioritize their efforts.
The five technical teams each proposed conservation targets -- the species, communities, and ecological systems that should be included in priority conservation areas.
If these areas are conserved, they will provide protection for both the identified target and an array of interdependent ecosystem elements
For each target, records of location and status were gathered and goals were developed to identify how many populations (for species targets) or how much area (for system targets) the portfolio should include to adequately represent each target.
Next, the SITES computer program was used to select the optimal portfolio of sites. This is the set of sites which met the goals of the most targets at the lowest cost.
Because of the preponderance of data and experience in the terrestrial arena, the terrestrial portfolio was used as the foundation for the combination of terrestrial, nearshore marine, and freshwater priorities.
Marine sites were added with an emphasis on capturing those places where high-priority terrestrial and marine areas were ecologically connected.
The Willamette Valley-Puget Trough-Georgia Basin Ecoregional Assessment has realized the following accomplishments or impacts:
The Willamette Valley-Puget Trough-Georgia Basin Ecoregional Assessment encountered the following challenges:
Willamette Valley-Puget Trough-Georgia Basin Ecoregional Assessment: http://www.ecotrust.org/placematters/assessment.html