Blue Mountains

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Lower Grande Ronde
The Lower Grande Ronde River in Oregon's Blue Mountains Ecoregion. Photo Credit: Keith Kohl, ODFW

Description

At 23,984 square miles, the Blue Mountains ecoregion is the largest ecoregion in Oregon. The Blue Mountains ecoregion is a diverse complex of mountain ranges, valleys, and plateaus that extends beyond Oregon into the states of Idaho and Washington. This ecoregion contains deep rock-walled canyons, glacially cut gorges, sagebrush steppe, juniper woodlands, mountain lakes, forests, and meadows. Broad alluvial-floored river valleys support ranches surrounded by irrigated hay meadows and agricultural fields. The climate varies because of elevational differences but, overall, the ecoregion has short, dry summers and long, cold winters. Because much of the precipitation falls as snow, snow melt gives life to the rivers and irrigated areas. 

Wood products and cattle production dominate the economy of the ecoregion, but agriculture along river valleys supports a variety of crops. The ecoregion sustains some of the most robust ungulate populations in the state and attracts tourists year-round, offering scenic lakes and rivers, geologic features, alpine areas, and numerous wildlife viewing opportunities. It includes the Prineville-Bend-Redmond metropolitan area, one of the fastest growing areas in the state, along with the cities of La Grande, Baker, Enterprise, and John Day. 

Characteristics

Important Industries

Agriculture, livestock (e.g., beef cattle, dairy cattle, sheep), forest products, manufacturing, outdoor recreation (e.g., hunting, fishing, skiing, camping, wildlife viewing) 

Major Crops

Wheat, alfalfa, grass seed, meadow hay, potatoes, onions, sugar beets, field corn

Important Nature-based Recreational Areas

John Day Fossil Beds National Monument, Hells Canyon National Recreational Area and Hells Canyon Wilderness, Wallowa Lake, Crooked River National Grasslands. Umatilla National Wildlife Refuge, John Day and Grande Ronde Rivers, Lake Billy Chinook, and Smith Rock State Park. Black Canyon, Mill Creek, Eagle Cap, Strawberry Mountain, North Fork John Day and Wenaha-Tucannon Wilderness Areas. Philip W. Schneider, Bridge Creek, Ladd Marsh, Wenaha, Elkhorn, and Minam Wildlife Areas. 

Elevation

1,000 feet (Snake River) – 9,838 feet (Sacajawea Peak) 

Important Rivers

Deschutes, Crooked, Burnt, Grande Ronde, Imnaha, John Day, Malheur, Powder, Silvies, Snake, Umatilla, Wallowa 

Ecologically Outstanding Areas

Malheur headwaters, Bear Valley, and the Umatilla-Walla Walla headwaters

Conservation Issues and Priorities

The Blue Mountains ecoregion contains some of the largest intact native grasslands in the state and several large areas managed for conservation values. Nonetheless, habitats have been impacted by interrelated changes in ecological processes due to fire suppression, selective harvest practices, and unsustainable grazing. These changes have increased the vulnerability of habitats to invasive species, disease, and uncharacteristically severe wildfire.  

Habitat loss has been the most severe in lower elevation valley bottom habitats, such as riparian areas, wetlands, and shrublands. These low-elevation habitats are highly fragmented where native vegetation has been converted to agricultural or urban land uses. Therefore, maintaining connectivity and corridors for wildlife is especially important in these areas. Other limiting factors, such as increasing recreational pressure and invasive species, have the potential to impact all habitats in this ecoregion. 

Key Conservation Issues of particular concern in the Blue Mountains ecoregion include Climate Change, Disruption of Disturbance Regimes (fire), Land Use Changes, Water Quality and Quantity, Barriers to Animal Movement, and Invasive Species. In addition to statewide issues, uncontrolled off-highway recreational vehicle use and unregulated horse herds are of increasing concern in this ecoregion. 

The Middle Fork John Day River in Oregon's Blue Mountain Ecoregion.
Photo Credit: USFS. The Middle Fork John Day River in Oregon’s Blue Mountains ecoregion.

Climate

The Blue Mountains climate has both continental and Mediterranean influences, with warm, dry summers and cold winters. Mean annual temperature and precipitation vary widely depending upon elevation.

Warming is projected in all seasons across the Blue Mountains, with the largest increases projected in the summer. Summer average temperature is projected to increase by as much as 8°F for the 2040-2069 period, and as much as 12°F by the end of the century under a high emissions scenario (SSP585; Figure 1). Winters in the Blue Mountains are also projected to become warmer, and summers drier. Late summer total precipitation is projected to decrease by as much as 12% for the 2069-2099 period (Figure 2). Cool season precipitation projections show an increase in precipitation of 16%, with more of it falling as rain instead of snow. Growing degree days are projected to more than double by the 2069-2099 period under the high emission scenario (SSP585). Frost days are projected to decrease from 210 per year to fewer than 150 per year, on average, by the end of the century.

Model median historical (1950-2010)


Photo Credit: ODFW.
Figure 1. Model median historical (1950-2010) and future projections of summer maximum temperature change for three periods (2010-2039, 2040-2069, 2070-2099) under a high emission scenario (SSP585) for the Blue Mountains. Future projections show increasing temperatures over the century, with slightly less warming in the southwestern Blue Mountains (Raymond and Fusco, 2024).
Model median historical (1950-2010) total late summer precipitation and projected percent change


Photo Credit: ODFW.
Figure 2. Model median historical (1950-2010) total late summer precipitation and projected percent change for three future periods (2010-2039, 2040-2069, 2070-2099) under a high emission scenario (SSP585) for the Blue Mountains. Future projections show decreasing late summer precipitation across the northern Blue Mountains throughout the century, and a slight increase for the southernmost Blue Mountains in the 2069-2099 time period. Confidence is low in projected changes in late summer precipitation after the 2010-2039 period due to variability among models (Raymond and Fusco, 2024).

Limiting Factors and Recommended Approaches

Limiting Factor:

Land Use Conversion and Urbanization
CMP Direct Threats 1, 2.1, 2.3, 7.2

The western portion of the Blue Mountains ecoregion includes the cities of Madras, Redmond, Prineville, and eastern Bend, one of the fastest growing metropolitan areas of the state. Rapid conversion to urban land uses threatens habitats and traditional land uses such as agriculture. Impacts to mule deer winter range are of particular concern. Northeast Oregon is increasingly popular with travelers, and habitat fragmentation due to rural development and recreation is a concern in some areas. While important economically, some agricultural uses contribute to habitat degradation for native fish and wildlife species. For example, open grazing allotments in forests have significantly damaged understory and riparian habitat in several areas.

Although many acres in this ecoregion are managed for wildlife and recreational values, these areas are primarily limited to higher mountain forests and alpine areas, or steep canyonlands. Lower elevation vegetation types, such as valley bottom grasslands, riparian areas, wetlands, and shrublands, are mostly on private lands. Most remnant low-elevation native habitats occur as fragmented patches with poor connectivity.

The Zumwalt Prairie in the Blue Mountains Ecoregion.
Photo Credit: Martin Nugent, ODFW. The Zumwalt Prairie in the Blue Mountains ecoregion.

Recommended Approach

Because important low-elevation habitats are primarily privately-owned, working with private landowners and local governments on voluntary cooperative approaches to improve habitat is the key to long-term conservation. Tools such as financial incentives, regulatory assurance agreements, and conservation easements may help landowners take actions to benefit species and habitats. Where feasible, maintain and restore habitats using a landscape approach to increase connectivity between habitat patches. Work with community leaders and local governments to ensure ecologically and environmentally conscientious growth. Support and implement existing land use regulations to preserve farmland and rangeland, open spaces, recreation areas, and natural habitats. Coordinate with local SWCDs, watershed councils, NRCS, and NGOs to communicate the importance of managing fish and wildlife habitats on private lands.

On public lands, unsustainable grazing should be curtailed. Federal land managers should develop adaptive grazing management plans that limit stocking rates based on ecological conditions and implement rotational grazing among allotments to allow for vegetation recovery. Incorporating emerging technologies like virtual fencing can help manage herd distribution more precisely, keeping animals out of riparian zones or other sensitive ecological areas without the need for physical barriers. Restoration activities can also improve habitat on degraded rangelands through removal of invasive species and reseeding with native vegetation.

Limiting Factor:

Altered Fire Regimes
CMP Direct Threats 7.1, 11.3, 11.4

In ponderosa pine habitat types, fire suppression and past forest practices have resulted in young, dense mixed-species stands where open, park-like stands of ponderosa pine once dominated. Increasing encroachment by smaller Douglas-firs and true firs places the forest at greater risk of severe wildfire, disease, and damage by insects. The spread of native junipers and non-native annual grasses throughout the ecoregion has also significantly increased fuel loads. Wildfire risk is further exacerbated by warming climate conditions and changes to patterns of precipitation, resulting in more frequent, higher intensity megafires. Dense understories and insect-killed trees make it difficult to reintroduce natural fire regimes because hazardous fuel levels increase the risk of stand-replacing fires. Additionally, young forests are often lacking in mature trees and snags that serve as critical wildlife habitat for some species. Efforts to reduce fire danger and improve forest health may help to restore habitats but require careful planning to provide sufficient habitat features that are important to fish (e.g., large woody debris, riparian vegetation) and wildlife (e.g., snags, downed logs, hiding cover). Similarly, wildfire reforestation efforts should be strategically planned to create stands with a diversity of tree age classes, understory vegetation, and natural forest openings.

The Buckhorn Lookout in the Blue Mountains Ecoregion.
Photo Credit: Martin Nugent, ODFW. The Buckhorn Lookout in the Blue Mountains ecoregion.

Recommended Approach

Use an integrated approach to forest health issues that considers historical conditions, fish and wildlife conservation, natural fire intervals, and silvicultural techniques. Encourage forest management at a broad scale to address limiting factors. Implement fuel reduction projects to reduce the risk of forest-destroying wildfires, considering site-specific conditions and goals. Fuel reduction strategies need to address the habitat structures that are important to wildlife, such as snags and downed logs, and work to maintain them at a level to sustain wood-dependent species. Reintroduce fire where feasible; prioritize sites and applications where intervention is likely to be most successful. Use prescribed burns to enhance quality of forage and cover for a diversity of species. Where fire is not feasible, explore alternatives, such as thinning and masticating, that can help mimic natural disturbance. Monitor forest health initiatives and use adaptive management techniques to ensure efforts are meeting habitat restoration and wildfire prevention objectives with minimal impacts on fish and wildlife. In the case of post-wildfire recovery, maintain high snag densities and replant with native tree, shrub, grass, and forb species. Manage reforestation after wildfire to create species and structural diversity, based on local management goals.

Limiting Factor:

Water
CMP Direct Threats 7.2, 11.4

Water quantity is a limiting factor for fish and wildlife. Changing climate conditions are leading to rising temperatures and altered patterns of precipitation, which affect water availability across different times of year. High demands for water, including for use in irrigation, can drastically reduce water availability. In streams, seasonal low flows due to changing climate conditions and over-allocation of water for agricultural uses can limit habitat suitability and reproductive success for many fish and wildlife species. In areas where urbanization is increasing, particularly in central Oregon around Bend, Madras, and Redmond, the demand for water is contributing to a decrease in the supply of groundwater. This reduces groundwater discharge of cold water to rivers and streams, subsequently reducing the availability of both cold water refugia and suitable habitat for cold-water dependent species. Water quality can also limit species and habitats. Runoff from agricultural areas can contaminate waterways. Warming temperatures, combined with higher nutrient levels due to agricultural runoff, is increasing the prevalence of toxic cyanobacterial blooms.

Recommended Approach

Provide incentives and information about water usage and sharing during low flow conditions (e.g., late summer). Promote water management actions that enable climate resilience and adaptation. Invest in watershed-scale projects for cold water and flow protection. Identify and protect cold water rearing and refugia habitat for aquatic species. 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.

Water tank escape ramps help birds, bats, and other small wildlife to climb out and avoid drowning.
Photo Credit: NRCS. Water tank escape ramps help birds, bats, and other small wildlife to climb out and avoid drowning.

Limiting Factor:

Invasive Species
CMP Direct Threat 8.1

Invasive plants and animals disrupt and degrade native communities, diminish populations of at-risk native species, and threaten the economic productivity of resource lands. Invasive plants, particularly noxious weeds, are easily spread and may quickly outcompete native species. While not as disruptive, invasive animals have caused problems for native fish and wildlife species and have become a nuisance and impacted people economically. In this ecoregion, unregulated horse herds, including the Murderers Creek herd and Big Summit herd, are of particular concern, competing with native wildlife for vegetation and access to water, and trampling sensitive riparian habitats. In aquatic habitats, smallmouth bass, walleye, brook trout and American bullfrogs are problematic invasives. Several mussel species, including zebra, quagga, and golden mussels, pose significant threats to aquatic systems. Non-native annual grasses, including cheatgrass, ventenata, and medusahead have rapidly expanded in perennial grass systems, displacing desirable forage for wildlife. Invasion of these species can also increase fuel loads by establishing in interspaces between sagebrush or other shrubs and perennial grasses, which were historically bare of vegetation.

Changing climate conditions and fire suppression have also led to the expansion of western juniper throughout the ecoregion. Western juniper is a native species, and  old growth juniper trees in rocky outcrops offer benefits to native wildlife. However, the expansion of western juniper in the Blue Mountains 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 riparian areas, junipers replace deciduous shrubs and trees that are more beneficial to riparian wildlife. 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 the open sagebrush or grassland habitats that are now in decline. These dense stands also act as fuel for wildfire, contributing to large, high-intensity fires that destroy sagebrush habitat.

Recommended Approach

Promote dialogue between fish and wildlife managers, landowners, and land managers to develop management plans based on common priorities. Engage in outreach to educate the public on the negative impacts of invasive species and provide information on how to prevent invasions. 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, biological) to control the most damaging invasive species. Emphasize efforts to focus on key invasive species in high priority areas, particularly where Key Habitats and Species of Greatest Conservation Need occur. Cooperate with partners through habitat programs to reduce noxious weeds and other invasive species and to educate people about invasive species issues. Promote the use of native plants for restoration and revegetation. At some sites in sagebrush communities, it may be desirable to use “assisted succession” strategies, using low seed rates of non-invasive non-native plants in conjunction with native plant seeds as an intermediate step in rehabilitating disturbances.

Limiting Factor:

Recreational Activity
CMP Direct Threats 1.3, 6.1

Activities like hiking, biking, hunting, fishing, camping, skiing, and off-road vehicle use can create sensory stressors for wildlife, with sound, light, and unusual smells that may deter species from moving through certain areas. Many species will avoid areas near trails, campgrounds, and access roads when humans are present. Human recreation may contribute to destruction of sensitive vegetation, harassment of wildlife from off-leash pets, and contamination of areas with refuse. Dispersed recreation can cause new roads and trails to fragment the landscape and can cause the spread of invasive species from other locations.

Recommended Approach

Plan new recreational trail systems carefully and with consideration for native wildlife and their habitats. Take advantage of abandoned or closed roads, rail lines, or previously impacted areas for conversion into trails. Work with land management agencies, such as the USFS, to designate areas as high value recreation and low habitat impact areas. Limit the use of motorized vehicles in sensitive areas, including off-road vehicles and electric bicycles. Institute road and/or area closures to protect species during sensitive times of year and decommission roads when possible. In high use areas, establish permitted entry systems to decrease recreational pressure. Engage in outreach to educate the public on the negative impacts of recreational activities and provide information on prevention. Follow guidelines for responsible recreation, such as Leave No Trace, to minimize impacts.

References

Raymond, C. L. and E. J. Fusco (Eds.). 2024. The State of Climate Adaptation Science for Ecosystems in the Northwest U.S. Prepared by the Climate Impacts Group for the Northwest Climate Adaptation Science Center. https://depts.washington.edu/nwclimateadaptation/socs/ 

Strategy Species

Conservation Opportunity Areas