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Vegetation

Shrub and Grassland Habitats

Shrub and grassland habitats encompass the following habitats.

Alpine

Alpine habitats support unique species in Oregon's high mountains. Most of the grass, forb and shrub dominated meadows, rocklands and slopes occur in a matrix with subalpine-woodlands, and are often folded into the subalpine parkland habitat below, so these are generally under-represented in our habitat maps. In spite of hardly being mapped, they are diverse enough to include 10 shrubland, herbaceous or barren ecological systems 1) Shrubland: Mediterranean California Alpine Fell-Field, North Pacific Dry and Mesic Alpine Dwarf-Shrubland, Fell-field and Meadow, Rocky Mountain Alpine Dwarf-Shrubland; 2) Herbaceous: Mediterranean California Alpine Dry Tundra, North Pacific Alpine and Subalpine Dry Grassland, Rocky Mountain Alpine Fell-Field, Rocky Mountain Alpine Turf; and 3) Barren: Mediterranean California Alpine Bedrock and Scree, North American Alpine Ice Field, North Pacific Alpine and Subalpine Bedrock and Scree, Rocky Mountain Alpine Bedrock and Scree.

Palouse Prairie

These are deep soiled, bunchgrass prairie, formerly widespread in eastern Washington, western Idaho, and occasional in north-central Oregon. They have almost been entirely converted to farmlands, with only small prairie remnants remaining. Idaho fescue, bluebunch wheatgrass, junegrass, Sandberg bluegrass dominate, with occasional basin wildrye, snowberry and rose growing as forbs, and patches of hawthorn and serviceberry. It is included in the Columbia Basin Palouse Prairie ecological system.

Palouse Prairie

Copyright Ellen Morris Bishop (Courtesy ODFW)

Northern Rocky Mountain Plateau and Valley Grassland

These are low to mid elevation grasslands found in the mountains and valleys of the northwest. They are dominated by large bunchgrasses (bluebunch wheatgrass, Idaho fescue, junegrass, or rough fescue) often with scattered (usually deciduous) shrubs and a diverse range of forbs. It also includes moist valley meadows dominated by Cusick bluegrass, slender wheatgrass, and introduced pasture grasses such as meadow foxtail or timothy. They sometimes occur in a matrix with forests or shrub steppe habitats. They are in the Northern Rocky Mountain Lower Montane, Foothill and Valley Grassland ecological system.

Subalpine Grassland

Found in eastern Oregon or the high Cascades, these are upper montane to subalpine grasslands, usually composed of dense bunchgrasses, found on ridges and mountain slopes, most commonly south facing areas. They occur as small isolated, sometimes moist grasslands in open montane conifer woodlands or subalpine parklands, or more extensive dry grasslands. Northern Rocky Mountain Subalpine-Upper Montane Grassland, Rocky Mountain Subalpine-Montane Mesic Meadow.

Subalpine Parkland

These are open, high mountain woodlands, usually mixed with open subalpine and alpine parklands, found in the northern Rocky Mountains. They are usually dominated by whitebark pine, subalpine fir, or mountain hemlock patches mixed with subalpine meadows and shrubs. They occur high elevation ridgetops, mountain slopes, talus slopes, rocksides and in cirque basins. They are often dry and windblown, with a limited understory of alpine sedges, grasses, forbs and dwarf shrubs, although they often include mountain meadows and wetlands around lakes. It includes the Rocky Mountain Subalpine-Montane Limber-Bristlecone Pine Woodland, Northern Rocky Mountain Subalpine Deciduous Shrubland, and North Pacific Maritime Mesic Subalpine Parkland.

Sagebrush and Desert Shrublands and Steppe

Sagebrush, bitterbrush, and rabbitbrush dominated shrublands and steppe habitats dominate most of southeastern Oregon, and are common throughout eastern Oregon. These are critical to the western sage grouse and a number of other sagebrush species, but are particularly threatened by invasive species, altered fire regimes, invasion of juniper and overuse. However, the Northern Basin and Range in southeastern Oregon has some of the best, intact sagebrush habitats remaining in the western U.S., and they are surprisingly diverse. The habitat includes 7 different ecological systems: Great Basin Xeric Mixed Sagebrush Shrubland, Inter-Mountain Basins Big Sagebrush Shrubland, Columbia Plateau Silver Sagebrush Seasonally Flooded Shrub-Steppe, Columbia Plateau Steppe and Grassland, Inter-Mountain Basins Big Sagebrush Steppe, Inter-Mountain Basins Montane Sagebrush Steppe, Inter-Mountain Basins Semi-Desert Shrub-Steppe.

Sage step

Copyright Bruce Tayler (Courtesy ODFW)

Moist Deciduous Shrubland

These are variable shrub dominated communities. In western parts of the state, they are often dense shrublands found scattered in small to occasionally large patches in coniferous forests, usually created by fire or other disturbance, but the shrubs can persist for decades or more, usually on the dry ridgetops, exposed south slopes or rocky sites where they are established. They also include canyon shrublands and moist shrublands formed by avalanches. They are part of the North Pacific Avalanche Chute Shrubland, North Pacific Montane Shrubland, and some canyon ecological systems.

Coastal Headlands and Islets

The headlands and islands along the coast include dense evergreen shrublands, open grasslands and forblands, exposed cliffs, and patches of wind-pruned conifers. They are small and are barely mapped, but support a distinct set of wildlife species. They are largely included in two ecological systems: North Pacific Hypermaritime Shrub and Herbaceous Headland and California Northern Coastal Grassland.

Columbia Basin Foothill and Canyon Dry Grassland

Bluebunch wheatgrass, Idaho fescue, Sandberg bluegrass, and needlegrass, along with diverse spring wildflowers, dominate this bunchgrass community found in the canyons and foothills of eastern Oregon. Some shrubs can occur here but these native grasslands still support primarily a wide array of native prairie species. This habitat is equivalent to the Columbia Basin Foothill and Canyon Dry Grassland ecological system.

Westside Montane Grasslands and Meadows

These habitats include dry, mountain grasslands in the Cascades and coastal mountains of the northwest, found on openings in mountain forests, and moist meadows found in small valley openings. Bunchgrasses dominate the dry meadows, while sedges, rushes and bunchgrasses dominate the meadows. They are part of two ecological systems: North Pacific Montane Grassland and Temperate Pacific Subalpine-Montane Wet Meadow.

Alkali and Desert Grasslands

These include dry grasslands, almost always dominated by widely spaced perennial bunchgrasses, usually in valley bottoms, flats or margins, in desert areas. These typically integrade into salt-desert shrubs or sagebrush, and support grasslands due to unusual soils (sand, gravel or alluvium), and low rainfall. They also include seasonally flooded areas dominated by alkaline grasses, such as basin wildrye,saltgrass and alkaligrass. They are either in the Inter-Mountain Basins Semi-Desert Grassland or the Inter-Mountain Basins Alkaline Closed Depression ecological system.

Westside Grasslands

These are either dry, upland prairies and savannas found in the valleys and foothills of Western Washington and Oregon, or grass and forb dominated cliffs, bluffs and grass balds found throughout these same areas. Dominated by native bunchgrasses and diverse forbs, they often have a minor savanna component of Oregon white oak, Douglas-fir and/or Ponderosa pine. They are part of either the Willamette Valley Upland Prairie and Savanna or the North Pacific Herbaceous Bald and Bluff ecological system.

Low and Rigid Sagebrush Steppe and Scablands

The volcanic plateaus of eastern Oregon create large areas of shallow soil and unique habitats, dominated by Sandberg bluegrass, buckwheat, rigid sagebrush and low sagebrush. While all support dense and showy spring wildflowers, they vary from almost barren habitats with mostly exposed rock, to productive, but low sagebrush steppe habitats higher in the mountains. They are in two systems: Columbia Plateau Scabland Shrubland and Columbia Plateau Low Sagebrush Steppe.

Chaparral

While occupying only small areas, mostly in southwestern Oregon, chaparral shrublands in Oregon are quite diverse. The most common chaparral species is buckbrush, a deciduous Ceanothus, but most of the types are dominated by tall evergreen shrubs which require fire for maintenance and reproduction. There are 6 different chaparral ecological systems in Oregon: Klamath-Siskiyou Xeromorphic Serpentine Savanna and Chaparral, California Maritime Chaparral, Northern and Central California Dry-Mesic Chaparral, Northern California Coastal Scrub, California Montane Woodland and Chaparral, California Xeric Serpentine Chaparral.

Salt Desert Scrub

In southeastern and south central Oregon, the large historic lake basins support significant patches of salt desert scrub habitat. Mixtures or pure stands of Black greasewood, spiny hopsage, shadscale, fourwing saltbush, and bud sagebrush are widely spaced in these relatively barren and dry habitats. There are two ecological systems found in Oregon: Inter-Mountain Basins Greasewood Flat and Inter-Mountain Basins Mixed Salt Desert Scrub.

Canyon Shrublands

Canyon shrublands represent an important and diverse habitat which is found throughout eastern Oregon, although best represented in Hells Canyon. Smooth sumac, hackberry (often a small tree), hawthorn, spiny greasebush, bitterbrush, serviceberry, ninebark, and sagebrush are the most important shrubs, but these are varied from dense tall shrublands to more open grassy areas with well distributed shrubs. The Northern Rocky Mountain Montane-Foothill Deciduous Shrubland and the Northern Rocky Mountain Subalpine Deciduous Shrubland are the only systems described for this habitat type.

Authored by Jimmy Kagan, INR Information Program Manager (2008)

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