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Dominated by modified Pacific air mass for at least half the year; mean July temperature over 18° C; over 2000 degree days in growing season; mean annual precipitation 200-500 mm with maximum in summer; annual evaporation from small lakes 800-1000 mm
3100 GRASSLAND-SHRUBLAND DIVISION
Mean January temperature -18 to -10° C; net annual radiation 48-50 W/m2. Chernozems. Grassland
3110 GRASSLAND PROVINCE
SOILS Brown and dark brown chernozems, brown solonetz
VEGETATION Grasses, forbs, shrubs; trees along rivers
FAUNA Mammals Bison, white-tailed deer, mule deer, wapiti, antelope
Birds Seasonal Mallard, redhead, American widgeon, canvasback, gadwall. Resident Greater prairie chicken, sharp-tailed grouse. Transient Waterfowl
Fish Unimportant (productivity less than 10)*3111 BLUESTEM PRAIRIE SECTION
LANDFORMS Lowlands, plains; flat to rolling; elevation 400-600 m, average 450 m
VEGETATION Tall grasses (big bluestem, little bluestem, switch grass, Indian grass), mid-grasses (needle grass), and forbs (composites and legumes)3112 WHEATGRASS-BLUESTEM-NEEDLEGRASS SECTION
LANDFORMS Plains; flat; elevation 150-900 m, average 600 m. Hummocky moraines and lake deposits
VEGETATION Mid-grasses (wheatgrass, grama grass, needlegrass), tall grasses (bluestem), composites, sedges. Along rivers: elm, ash, birch, cottonwood. In east: scattered oak3113 GRAMA GRASS-NEEDLEGRASS-WHEATGRASS SECTION
LANDFORMS Plains; flat, rise in elevation westward; elevation 610-1800 m, average 1000 m. Hummocky disintegration moraine, till; unglaciated in south
VEGETATION Short grass prairie (grama grass, wheatgrass, needle-grass); ash, cottonwood, and shrubs along rivers3114 WHEATGRASS-NEEDLEGRASS SECTION
LANDFORMS Plateaus, foothills, low mountains; rolling to locally rugged; elevation 450-2000 m, average 500 m
VEGETATION Mid-grasses (needle grass, western wheatgrass), short grasses (blue grama), and composites
M3120 ROCKY MOUNTAIN FOREST PROVINCE
SOILS Grey-brown and grey luvisols, dark brown chernozems
VEGETATION Forests with grassland in some valleys
FAUNA Mammals Mule deer, elk, bighorn sheep, moose, beaver
Birds Resident Blue grouse, ruffed grouse, quail. Transient Waterfowl
Fish Staple (productivity 140-170). Freshwater Salmon, trout, white-fish, sturgeon, squawfish, suckers*M3121 GRAND FIR-DOUGLAS FIR SECTION
LANDFORMS Plateaus and mountains; rolling to rugged; elevation 500-3000 m, average 1 800 m
VEGETATION Coniferous forest (grand fir, Douglas fir, western larch, western white pine, trembling aspen)*M3122 DOUGLAS FIR SECTION
LANDFORMS Mountains ; rugged; elevation 1800-3600 m, average 2600m
VEGETATION Coniferous forest (Douglas fir, white fir, white spruce, lodgepole pine, ponderosa pine, trembling aspen)
3130 PALOUSE PROVINCE
SOILS Dark brown chernozem on loess
VEGETATION Grasses with few shrubs
FAUNA Mammals Mule deer, antelope, wapiti, jack rabbit
Birds Resident Sharp-tailed grouse, quail
Fish Most important staple (productivity 140-170). Freshwater Salmon, trout, whitefish, sturgeon, squawfish, suckers*3131 WHEATGRASS-FESCUE-BLUEGRASS SECTION
LANDFORMS Plateaus; hilly; elevation 200-1200 m, average 1000 m
VEGETATION Low to medium-tall grassland (bluebunch wheatgrass, Idaho fescue, Bandberg blue grass)
3140 INTERMONTANE SHRUBLAND PROVINCE
SOILS Desert soils, alluvium, dry lake beds
VEGETATION Shrubs with sparse grasses
FAUNA Mammals Antelope, bighorn sheep, mule deer, wapiti, jack rabbit
Birds Resident Sage grouse, quail. Transient Sandhill crane, waterfowl
Fish Local staple along large rivers (productivity up to 170). Freshwater Salmon, sturgeon, whitefish, trout, squawfish, suckers*3141 SAGEBRUSH-WHEATGRASS SECTION
LANDFORMS Plains with low to high mountain ranges; flat to locally rugged; elevation 500-2800 m, average 1500 m
VEGETATION Dense to open shrubland and grassland (sagebrush, bluebunch wheatgrass, Idaho fescue), sparse coniferous forest of juniper on mountains*3145 PONDEROSA PINE WOODLAND SECTION
LANDFORMS Mountains and foothills, locally rugged; elevation 1000-1800 m, average 1500 m
VEGETATION Open coniferous forest with shrubs (ponderosa pine, Douglas fir, manzanitas, mountain mahogany, ninebark, bitterbrush, snowberries)
3150 WYOMING BASIN PROVINCE
SOILS Desert soils, alluvium, dry lake beds, dune sand, loess
VEGETATION Shrubland with grasses
FAUNA Mammals Bison, antelope, mule deer, jack rabbit
Birds Resident Sage grouse. Transient Waterfowl
Fish Unimportant (productivity less than 10). Freshwater Suckers*3151 WHEATGRASS-NEEDLEGRASS-SAGEBRUSH SECTION
LANDFORMS Plains with hills and low mountains; rolling; elevation 1000-1800 m, average 1200 m
VEGETATION Grassland with scattered dwarf shrubs (western wheatgrass, plains bluegrass, needle-and-thread grass, sagebrushes, grease wood)
M Mountainous section
* Ecological regions that are confined to the United States and/or modified from Bailey (1980)
