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Northern Great Basin Rapid Ecoregional Assessment (REA)Status | Location and Setting | Management Questions | Conservation Elements | Change Agents | Data, Maps, and Models | Memos and Reports REA Status Location and Setting It is the northern extent of the larger Basin and Range physiographic province, and is characterized by high arid basins alternating with isolated fault block mountains including Steens Mountain and Hart Mountain. Repeated glaciations and stream erosion have carved dramatic valleys in these mountains and in the Owyhee High Plateau.
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Location Map
Most of the ecoregion is dominated by sagebrush steppe ecosystems on the desert floor, but distinct vegetation zones related to relief and elevation also exist. The desert floor is characterized by big sagebrush (Artemisia tridentata), low sagebrush (Artemisia arbuscula)-and salt-desert shrub systems. With increasing elevation, the higher plateaus and rocky areas support western juniper (Juniperus occidentalis) and curlleaf mountain mahogany (Cercocarpus ledifolius) communities. Aspen (Populus tremuloides) communities grow along streams and drainages in the mountain gorges and riparian zones, providing an important source of forage for deer and other wildlife. Isolated stands of Douglas-fir (Pseudotsuga menziesii) and whitebark pine (Pinus albicaulis) also occur in the mountains. The subalpine zone supports low-growing shrubs, grasses, and wildflowers such as mountain meadow knotweed (Polygonum bistortoides) and false hellebore (Veratrum viride).
Terrestrial wildlife species of concern include bighorn sheep ( Ovis canadensis ), mule deer (Odocoileus hemionus), elk (Cervus elaphus), pronghorn (Antilocapra americana), pygmy rabbit (Brachylagus idahoensis), snowshoe hare (Lepus americanus), golden eagle (Aquila chrysaetos), and greater sage-grouse (Centrocercus urophasianus). Important habitats in the ecoregion include migration corridors and areas for overwintering pronghorn, as well as seasonal habitats for greater sage-grouse. The Northern Basin and Range ecoregion also supports thousands of migratory waterfowl in the Malheur Lake area, and populations of the Lahontan cutthroat trout (Oncorhynchus clarkii henshawi), redband trout (Oncorhynchus mykiss), bull trout (Salvelinus confluentus), warm water fish, bat species, and spotted frog (Rana luteiventris).
Management Questions
The management questions for the NGB were finalized in February 2012 in the NGB Task 1 Final Memorandum. Initially 78 questions, organized in 6 categories, were formulated to guide the REA. They seek information related to:
- Terrestrial ecological features, functions, and services as conservation elements
- Species and groups of species as conservation elements
- Terrestrial sites of regional importance as conservation elements
- Hydrologic features, functions, and services conservation elements
- Aquatic sites of regional importance as conservation elements
- Change agents, including, but not limited to: climate change, development, fire and invasive species
Conservation Elements
Conservation elements are resources of conservation concern within an ecoregion. This REA will assess the current status and forecast the future condition of these conservation elements. A full list and description of conservation elements can be found in the Phase 1 Task 1 Memo.
In brief, the coarse-filter conservation elements for the NGB REA include sagebrush, salt desert shrub, juniper species, aspen, streams and rivers, springs and seeps, groundwater, and wetlands.
Examples of fine-filter conservation elements include mule deer, greater sage grouse, golden eagle, pygmy rabbit, bighorn sheep, and bats.
Change Agents
Change agents are disturbances on the landscape that can influence ecosystem health. They can have natural causes, such as wildfire; human causes, such as energy development; or result from the interaction of both, such as climate change. A key purpose of this REA is to understand the influences of significant, widespread change agents on the natural resources (represented by the conservation elements discussed above) of the NGB Ecoregion.
This REA will examine the potential effects of the following change agents. A more complete discussion of change agents is presented in the Task 1 Final Memorandum.
Change Agents to be Addressed in the Northern Great Basin REA | ||
| Wild Fire | ||
Invasive Species | ||
Development: | ||
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| Climate Change | ||
Data, Maps, and Models
Geospatial data, maps, and models used in and produced by the REAs will be made available to the public upon final completion of each individual assessment.
Memos and Reports
For each REA, there is a series of memos which are supplemental documents to the final report. Memos document the major tasks and decision points made during the assessments and provide pertinent background information necessary to understand the justification and methods used during the assessment. As memos and the final report are completed, they can be downloaded through the table below.
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Description | Document Link |
| Management questions, conservation elements, and change agents | Task 1 Final Memorandum (PDF) |
| Datasets for analysis | Task 2 Final Memorandum (PDF) |
| Analytical models and tools | Task 3 Final Memorandum (PDF) |
| REA work plan | Task 4 Final Workplan (PDF) |
| Preliminary findings for review | |
| REA report, maps, and supporting documents |
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