Northern Basin and Range

Trout Creek Mountains
Northern Basin and Range Ecoregion Photo Credit: Rodney Klus, ODFW


The Northern Basin and Range ecoregion is sagebrush country. It is Oregon’s slice of the Old West, with rich ranching and farming traditions.

The Northern Basin and Range ecoregion covers the southeastern portion of the state, from Burns south to the Nevada border and from the Christmas Valley east to Idaho. The name describes the landscape, numerous flat basins separated by isolated mountain ranges. Several important mountains are fault blocks, with gradual slopes on one side and steep basalt rims and cliffs on the other side. The Owyhee Uplands consist of a broad plateau cut by deep river canyons. Elevations range from 2,070 feet near the Snake River to more than 9,700 feet on the Steens Mountain.

In the rain shadow of the Cascades Mountains, the Northern Basin and Range is Oregon’s driest ecoregion marked by extreme ranges of daily and seasonal temperatures. Much of the ecoregion receives less than 15 inches of precipitation per year, although mountain peaks receive 30-40 inches per year. The extreme southeastern corner of the state has desert-like conditions, with annual precipitation of only 8-12 inches. Runoff from precipitation and mountain snowpack often flows into low, flat playas where it forms seasonal shallow lakes and marshes. Most of these basins contained large, deep lakes during the late Pleistocene, between 40,000 and 10,000 years ago. As these lakes, which don’t drain to the ocean, dried through evaporation, they left salt and mineral deposits that formed alkali flats, extremely important stopover sites for migratory shorebirds due to the rich source of invertebrate prey.

Sagebrush communities dominate the landscape. Due to the limited availability of water, sagebrush is usually widely spaced and associated with an understory of forbs and perennial bunchgrasses, such as bluebunch wheatgrass and Idaho fescue. The isolated mountain ranges have few forests or woodlands, with rare white fir stands in Steens Mountain and Hart Mountain. However, aspen and mountain mahogany are more widespread and can be found in the Trout Creeks, Steens Mountain, Pueblo Mountains, Oregon Canyon Mountain, and Mahogany Mountains. In the southern portion of the ecoregion, there are vast areas of desert shrubland, called salt-desert scrub, dominated by spiny, salt-tolerant shrubs. Throughout the ecoregion, soils are typically rocky and thin, low in organic matter, and high in minerals.

The Northern Basin and Range ecoregion is sparsely inhabited, but the local communities have vibrant cultural traditions. The largest community is Ontario, with more than 11,000 people. Other communities include Nyssa, Vale, Burns, and Lakeview, with 2,400 to 3,100 people each. Land ownership is mostly federal and primarily administered by the BLM. Livestock and agriculture are the foundations of the regional economy. Food processing is important in Malheur County. Recreation is a seasonal component of local economies, particularly in Harney County. Hunting contributes to local economies, as does wildlife viewing, white-water rafting, and camping. Historically, lumber processing and harvesting from the nearby Blue Mountains was the basis of some local communities, particularly for Burns. However, these industries have declined with lower harvests from neighboring federal forests.


Important Industries

Livestock, forest products, agriculture, food processing, recreation

Major Crops

Alfalfa, wheat, hay, corn, oats, onions, sugar beets, potatoes


2,070 feet (Snake River) to 9,733 feet (Steens Mountain)

Important Rivers

Donner und Blitzen, Malheur, Owyhee, Silvies

Conservation Issues and Priorities

Uncontrolled livestock grazing in the decades before enactment of the Taylor Grazing Act of 1934 caused serious long-term ecological damage throughout the ecoregion. Rangeland conditions have substantially improved since then in most areas, and grazing is managed sustainably in many parts of the ecoregion. However, some areas are still impacted. In addition, sensitive areas, such as riparian habitats and arid areas of sagebrush and salt desert, have been slow to recover.

Some areas are still recovering from intensive management in the past. For example, the BLM began a massive effort in 1962 to rehabilitate degraded rangelands by removing the native sagebrush and establishing crested wheatgrass, a non-native pasture grass. Over the course of 10 years, the Vale Rehabilitation Project seeded 250,000 acres to crested wheatgrass and used plowing, chaining, and herbicides to reduce sagebrush on as much as 506,000 acres. Currently, the BLM maintains extensive wilderness areas in this ecoregion, including the Malheur Refuge, Hart Mountain, Steens Cooperative Management and Protection Area, and BLM Areas of Critical Environmental Concern at Lake Abert, Warner Valley, and Owyhee canyons.

Historical overgrazing and fire suppression, followed by invasion of non-native annual grasses such as cheatgrass, have greatly altered natural fire cycles in many sagebrush steppe habitats. Landscapes formerly comprised of mosaics dominated by bunchgrasses and forbs are now heavily and disproportionately dominated by shrubs (mostly sagebrush) and exotic grasses and forbs. Invasive species and altered fire regimes are the greatest terrestrial conservation issues in this ecoregion. As a result of altered fire regimes, encroachment of juniper has displaced grasses and sagebrush, especially in the northern portions of the ecoregion. However, old-growth juniper occurs in some areas, especially in rock outcrops where grasses and sagebrush are uncommon and where fire is less of a factor. These old-growth juniper are extremely beneficial to wildlife.

Greater Sage-Grouse are considered excellent indicators of sagebrush habitat quality. Current efforts to improve conditions for the Greater Sage-Grouse include comprehensive range-wide assessments and conservation planning.

Stream water quality in the Northern Basin and Range ecoregion is poor when compared to other ecoregions. Throughout the Northern Basin and Range ecoregion, water quality is impacted by high temperatures, and in some areas, by bacteria, pollutants, and aquatic weeds. Water is limited in the ecoregion, fully allocated in storage and other uses. Aquatic habitats are affected by altered channel and flow conditions, obstructions, and poor riparian condition. Efforts to assess the quality of aquatic habitats are ongoing, and priorities include assessment of the impact of federal dams on water quantity, and obtaining an understanding of natural temperature and water quality dynamics in the ecoregion. Under climate change, drought conditions may become more frequent, resulting in reduced water availability for wetlands in important wildlife areas like Summer Lake, Lake Abert, and Malheur Lake.

Key Conservation Issues in the Northern Basin and Range ecoregion include Invasive Species, Water Quality and Quantity, and Disruption of Disturbance Regimes. In addition to the statewide issues, increasing demand for energy development, ongoing recovery from historical overgrazing, unregulated horse herds, uncontrolled OHV use, and increasing recreational demand are issues in this ecoregion.

Limiting Factors and Recommended Approaches

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. The Northern Basin and Range ecoregion offers excellent renewable energy resources that are useful to address climate change in the ‘big picture’, but the ecoregion is sensitive to local impacts on sagebrush and other habitats.

Recommended Approach

Plan energy projects carefully, using best available information and consultation with biologists. Use available tools and resources found in the Land Use Changes and Climate Change KCIs and ODFW Compass.

Limiting Factor:

Invasive Species

Invasive plants, including noxious weeds and cheatgrass, are of particular concern in the Northern Basin and Range ecoregion. They disrupt native communities, diminish populations of at-risk native species, and threaten the economic productivity of resource lands. Invasive plants have been increasing during the last 80 years. The spread of cheatgrass and medusahead can increase the frequency, intensity, and spread of fires, replacing sagebrush and native bunchgrasses, which are adapted to infrequent, patchy fires. While not nearly as extensive as invasive plants, non-native animals have also impacted native fish and wildlife populations. For example, invasive carp in Malheur Lake have damaged one of the most important waterfowl production areas in Oregon, altering ecological dynamics through predation and altering water quality by disturbing sediments (see this video clip for more information).

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. Prioritize efforts to focus on key invasive species in high priority areas, particularly where Strategy Habitats and Strategy Species occur. Cooperate with partners through habitat programs and county weed boards to address invasive species problems. Use of fire helps treat juniper or medusa head. Carefully manage wildfires in cheatgrass-dominated areas. Promote the use of native “local” stock for restoration and revegetation where native species have the greatest potential to successfully establish. In some cases, use “assisted succession” strategies, applying low seed rates of non-invasive non-native plants in conjunction with native plant seeds as an intermediate step in rehabilitating disturbances in sagebrush communities.

Limiting Factor:

The Spread of Western Juniper and Altered Fire Regimes

Although an important native woodland tree in the East Cascades ecoregion, western juniper has been rapidly expanding its range over the last 40 years. The reasons for this expansion are not clear, although changes in fire regimes, overgrazing, and climate changes may have a role. This rapid expansion of western juniper has degraded some grassland, sagebrush, riparian, large-diameter juniper, and aspen habitats. Western juniper expansion may reduce water availability in many seasonal and some perennial streams. In many of the grassland and sagebrush habitats, 20-30 year old juniper trees form dense stands that are not suitable for many wildlife species that require open sagebrush or grassland habitats that are now in decline. In riparian areas, junipers replace deciduous shrubs and trees that are more beneficial to riparian wildlife. Western juniper is a native species, and old growth juniper trees in rocky outcrops offer benefits to native wildlife.

Most big sagebrush-dominated areas were once a mosaic of successional stages, from recently burned areas dominated by grasses and forbs to old sagebrush-dominated stands that have not burned for 80 to 300 years. However, changes in fire patterns have reduced this mosaic and resulted in large areas dominated by invasive annual grasses, or older big sagebrush with an understory of invasive annual plants.

Increasingly dry conditions are contributing to increased frequency of fires, resulting in landscapes that are susceptible to the spread of western juniper and cheatgrass. Previously, fire suppression resulted in undesirable changes in vegetation, contributing to the build-up of woody plants that increase the intensity of fires. Areas dominated by cheatgrass or other invasive annual grasses are more conducive to fire ignition and reburning.

While a useful tool, prescribed fire might not be suitable for some sagebrush habitats because some sagebrush communities are very slow to recover from a fire. Big sagebrush communities with non-native invasive annuals in the understory will not recover from fire without significant intervention.

Recommended Approach

Controlling western juniper in newly invaded areas benefits wildlife and other habitat values. Early control of newly invaded young trees before woodlands become established is often the most successful approach.

In some areas, fire can be used to control young juniper. Carefully evaluate sites to determine if prescribed fire is appropriate, considering the landscape context and vegetation types. Under current vegetation management conditions, fire is damaging to sagebrush stands. If determined to be ecologically beneficial, reintroduce natural fire regimes using site-appropriate prescriptions that account for the historical fire regime, as well as area size and vegetation characteristics that affect resiliency and resistance to disturbance. Use prescribed fire to create a mosaic of successional stages, and avoid large prescribed fires.

In areas where prescribed fire is not practical, use mechanical treatment methods (e.g., chipping, cutting for firewood) that minimize soil disturbance. Chemical, mechanical, or biological management techniques can be combined along with prescribed fire.

Develop markets for small juniper trees as a special forest product to reduce restoration costs. Maintain large-diameter juniper trees in the native rocky outcrops and ridges, which are important nesting habitat for passerines and raptors.

Limiting Factor:

Ongoing Recovery From Historical Overgrazing

Prior to limitations that were initiated on public lands in the mid-1930s, livestock grazing had a profound influence on landscapes throughout the Northern Basin and Range ecoregion. Many areas experienced serious ecological damage. Conditions on rangelands in general have improved substantially over the past half-century as a result of improvements in livestock management, and most ecosystems are recovering. However, some habitats have been slow to recover, such as some riparian areas and sagebrush communities, especially where cheatgrass has invaded.

Recommended Approach

Continue to proactively manage livestock grazing and restore degraded habitats. Minimize grazing during restoration of highly sensitive areas, such as wetlands and riparian areas.

Limiting Factor:

Uncontrolled Off-highway Vehicle Use

Use by OHVs continues to increase. While limited and controlled, OHV use can be compatible with wildlife conservation. Unlimited and uncontrolled use can:

  • impact riparian, aquatic, and upland habitats
  • spread invasive plant seeds
  • affect wildlife behavior and distribution, especially during critical breeding and wintering periods
  • damage soils
  • increase risk of wildfires

Although OHV use is limited to designated roads in some sensitive landscapes, there is little to no enforcement due to lack of funds and law enforcement personnel.

Recommended Approach

Work cooperatively with land managers and OHV groups to direct use to maintained trails in low-impact areas and improve enforcement of existing rules. Support educational efforts to promote low-impact recreational use such as the Tread Lightly! Program. Monitor OHV impacts at priority areas. Support efforts to effectively manage OHV use on public lands, particularly in highly sensitive habitats, and restore damaged areas.

Limiting Factor:

Unmanaged Recreational Use

In addition to OHV use, other recreational use, such as camping, rock climbing, and parasailing, is increasing. Although recreational use is still light in comparison to other ecoregions, new uses could compound impacts to wildlife by increasing disturbance and making previously remote areas more accessible to people.

Recommended Approach

Proactively consider potential impacts to wildlife and habitats when developing or promoting recreational opportunities to encourage compatible uses. Monitor recreational patterns and trends.

Limiting Factor:

Unregulated Horse Herds Disturb Wildlife and Compete for Water and Other Resources

Oregon’s herds of wild horses are a well-recognized feature on rangeland, but the herds require intensive management attention, including resource-intensive adoption and translocation programs allowed under the Wild Horse & Burro Act (BLM 1971). Unregulated horse herds negatively impact native vegetation, compete with wildlife for water and food, and disrupt habitat use by wildlife. The effects of climate change are likely to exacerbate these impacts.

Recommended Approach

Promote dialogue between wildlife managers, land owners, and land managers to develop management plans based on common priorities. Managing horse and burro populations is critical, both for their well-being and for ecosystem health. Promote outreach to explain the issue to the public. Use opinion polling results to inform management decisions and help agencies balance multiple priorities.

Limiting Factor:

Water Distribution in Arid Areas and Wildlife Entrapment in Water Developments

In arid areas, water availability can limit animal distribution. Water developments established for domestic livestock and wildlife can significantly benefit birds, bats, and small mammals. However, some types of these facilities, particularly water developments for large ungulates, can have unintentional hazards. These hazards include over-hanging wires that act as trip lines for bats, steep side walls that act as entrapments under low water conditions, or unstable perches that cause animals to fall into the water. If an escape ramp is not provided, small animals cannot escape and will drown.

Recommended Approach

Continue current efforts to provide water for wildlife in arid areas. Continue current design of big game “guzzlers” that accommodate a variety of species, and retrofit older models where appropriate to make them compatible with newer design standards. Use and maintain escape devices on water developments where animals can become trapped. Remove obstacles that could be hazardous to wildlife from existing developments.


Strategy Species

Conservation Opportunity Areas