Columbia Plateau

An aerial view of the Rock Creek - Butter Creek Grasslands COA in the Columbia Plateau Ecoregion. Photo Credit: Steve Cherry, ODFW


The Oregon portion of the Columbia Plateau ecoregion extends from the eastern slopes of the Cascade Mountains to the Blue Mountains ecoregion. Millions of years ago, the region was covered by lava flows up to 2 miles deep. The Columbia River delineates the northern border of the ecoregion in Oregon, and has greatly influenced the surrounding area with cataclysmic floods and large deposits of wind-borne silt and sand. Over time, winds scoured the floodplain, depositing silt and sand across the landscape and creating ideal conditions for agriculture: rolling lands, deep soil, and plentiful flowing rivers including the Deschutes and John Day. The ecoregion is made up entirely of lowlands, with an arid climate, cool winters, and hot summers.

The Columbia Plateau produces the vast majority of Oregon’s grain, and grain production is the heart of the agricultural economy. The Columbia Plateau produces the second-highest agricultural sales per year for any ecoregion in Oregon. More than 80 percent of the ecoregion’s population and employment is located in Umatilla County, which includes the cities of Pendleton and Hermiston. Other population centers include The Dalles, Condon, and Heppner.


Important Industries

Agriculture, mobile home production, cattle, retail and services, construction

Major Crops

Grain, barley, potatoes, onions, fruit

Important Nature-based Recreational Areas

Cold Springs National Wildlife Refuge (NWR), Umatilla NWR, the canyons of the lower Deschutes and John Day Rivers


100 feet (The Dalles) to 3,000 feet (northern slopes)

Important Rivers

Columbia, Deschutes, John Day, Umatilla, Walla Walla

Conservation Issues and Priorities

Almost all of the Columbia Plateau ecoregion is privately owned. Conservation opportunities for native vegetation are limited because it is difficult to maintain connectivity among high quality habitat patches.

Water availability is a concern in this ecoregion, and demands for water include agricultural, irrigation, and domestic use. Water quality in the Columbia Plateau ecoregion is affected by these demands, particularly in summer months when flows are reduced. Restoring flow to headwater streams is essential to maintain ecological connections. Maintaining aquifers is also critical.

Key Conservation Issues of particular concern in this ecoregion include Water Quality and Quantity and Invasive Species. In addition to the statewide issues, soil erosion, habitat fragmentation, and large-scale energy development are of conservation concern in this ecoregion.

Limiting Factors and Recommended Approaches

Limiting Factor:

Water Availability

Water quantity is a limiting factor for fish, wildlife, and livestock. In streams, seasonal low flows can limit habitat suitability and reproductive success for many fish and wildlife species. As the demand for water increases, the supply of groundwater is decreasing. Water quality can also limit species and habitats.

Recommended Approach

Provide incentives and information about water usage and sharing during low flow conditions (e.g., late summer). Increase awareness and manage timing of applications of potential aquatic contaminants. Improve compliance with water quality standards and pesticide use labels administered by the DEQ and EPA. Work on implementing Senate Bill 1010 (Oregon Department of Agriculture) and DEQ Total Maximum Daily Load water quality plans.

Limiting Factor:

Soil Erosion

Soil loss through erosion and decreases in soil quality jeopardize the productivity of native habitats and agricultural lands. Water infiltration, which is essential for productive habitats and groundwater recharge, decreases on bare land soils. Sandy soils along the Columbia River are particularly susceptible to erosion from high winds.

Recommended Approach

Use incentives to promote no-till farming and agricultural practices that do not allow lands to lay bare for long periods of time. Encourage participation and support for programs such as the Natural Resources Conservation Service’s Conservation Reserve Program, which promote practices that can offset or minimize soil erosion and degradation.

Limiting Factor:

Habitat Fragmentation

The remaining Strategy Habitats for at-risk native plant and animal species are limited and largely confined to small and often isolated fragments, such as roadsides and sloughs. These remaining parcels have potential to be converted to agriculture, and there are few opportunities for large-scale protection or restoration of native landscapes. Existing land use and land ownership patterns present challenges to large-scale ecosystem restoration.

Recommended Approach

Provide incentives (e.g., financial assistance, conservation easements) and information about the benefits of maintaining bird and other wildlife habitat. Broad-scale conservation strategies will need to focus on restoring and maintaining more natural ecosystem processes and functions within a landscape that is managed primarily for other values. This may include an emphasis on more “conservation-friendly” management techniques for existing land uses, and restoration of some key ecosystem components such as riparian function. “Fine-filter” conservation strategies that focus on needs of individual Strategy Species and key sites are particularly important in this ecoregion. Because approximately 84 percent of the Columbia Plateau ecoregion is privately-owned, voluntary cooperative approaches are the key to long-term conservation using tools such as financial incentives, regulatory assurance agreements, and conservation easements. Where appropriate, plan development carefully to maintain existing native habitats.

Limiting Factor:

Invasive Species

Invasive plant and animal species disrupt native communities, diminish populations of at-risk native species, and threaten the economic productivity of resource lands including farmland and rangeland. Differences in county policies and funding availability regarding invasive species have resulted in some inconsistencies in approach.

Recommended Approach

Emphasize prevention, risk assessment, early detection, and quick control to prevent new invasive species from becoming fully established. Use multiple site-appropriate tools (e.g., mechanical, chemical and biological) to control the most damaging invasive species. Focus on key invasive species in high priority areas, particularly where Strategy Habitats and Strategy Species occur. Ensure cooperation and collaboration between counties, landowners, land managers, and other entities with invasive species policies and interests. Promote the use of native species for restoration and revegetation.

Limiting Factor:

Energy Development

Climate change and global economies are increasing pressure for renewable energy development, including wind and geothermal energy. Energy projects offer environmental benefits but also have impacts on fish, wildlife, and their habitats. Wind energy potential is especially high in the Columbia Plateau. The area is increasingly challenged with the need to balance the state’s interest in clean energy development with local natural resource conservation needs.

Recommended Approach

Plan energy projects carefully, using best available information and consultation with biologists. See the Key Conservation Issue on Land Use Changes and the Oregon Columbia Plateau Ecoregion Wind Energy Siting and Permitting Guidelines.

Strategy Species

Conservation Opportunity Areas