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The Northern Basin and Range ecoregion is a Level III ecoregion designated by the
United States Environmental Protection Agency The Environmental Protection Agency (EPA) is an independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon proposed the establishment of EPA on July 9, 1970; it ...
(EPA) in the U.S. states of
Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...
,
Idaho Idaho ( ) is a U.S. state, state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Monta ...
,
Nevada Nevada ( ; ) is a U.S. state, state in the Western United States, Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. N ...
,
Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to its ...
, and
California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...
. It contains dissected lava plains, rolling
hill A hill is a landform that extends above the surrounding terrain. It often has a distinct summit. Terminology The distinction between a hill and a mountain is unclear and largely subjective, but a hill is universally considered to be not a ...
s,
alluvial fan An alluvial fan is an accumulation of sediments that fans outwards from a concentrated source of sediments, such as a narrow canyon emerging from an escarpment. They are characteristic of mountainous terrain in arid to semiarid climates, but a ...
s,
valley A valley is an elongated low area often running between hills or mountains, which will typically contain a river or stream running from one end to the other. Most valleys are formed by erosion of the land surface by rivers or streams ove ...
s, and scattered
mountain range A mountain range or hill range is a series of mountains or hills arranged in a line and connected by high ground. A mountain system or mountain belt is a group of mountain ranges with similarity in form, structure, and alignment that have ari ...
s in the northern part of the
Great Basin The Great Basin is the largest area of contiguous endorheic watersheds, those with no outlets, in North America. It spans nearly all of Nevada, much of Utah, and portions of California, Idaho, Oregon, Wyoming, and Baja California. It is noted fo ...
. Although
arid A region is arid when it severely lacks available water, to the extent of hindering or preventing the growth and development of plant and animal life. Regions with arid climates tend to lack vegetation and are called xeric or desertic. Most ...
, the
ecoregion An ecoregion (ecological region) or ecozone (ecological zone) is an ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than a biogeographic realm. Ecoregions cover relatively large areas of ...
is higher and cooler than the
Snake River Plain The Snake River cutting through the plain leaves many canyons and Canyon#List of gorges">gorges, such as this one near Twin Falls, Idaho The Snake River Plain is a geologic feature located primarily within the U.S. state of Idaho. It stre ...
to the north and has more available moisture and a cooler
climate Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorologi ...
than the Central Basin and Range to the south. Its southern boundary is determined by the highest shoreline of
Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
Lake Bonneville Lake Bonneville was the largest Late Pleistocene paleolake in the Great Basin of western North America. It was a pluvial lake that formed in response to an increase in precipitation and a decrease in evaporation as a result of cooler temperature ...
, which once inundated the Central Basin and Range. The western part of the region is internally drained; its eastern stream network drains to the
Snake River The Snake River is a major river of the greater Pacific Northwest region in the United States. At long, it is the largest tributary of the Columbia River, in turn, the largest North American river that empties into the Pacific Ocean. The Snake ...
system. The valleys support
sagebrush steppe Sagebrush steppe is a type of shrub-steppe, a plant community characterized by the presence of shrubs, and usually dominated by sagebrush, any of several species in the genus '' Artemisia''.saltbush Saltbush is a vernacular plant name that most often refers to ''Atriplex'', a genus of about 250 plants distributed worldwide from subtropical to subarctic regions. ''Atriplex'' species are native to Australia, North and South America, and Eurasia. ...
vegetation. Mollisol soils are common, in contrast to the aridisols of the Central Basin.
Juniper Junipers are coniferous trees and shrubs in the genus ''Juniperus'' () of the cypress family Cupressaceae. Depending on the taxonomy, between 50 and 67 species of junipers are widely distributed throughout the Northern Hemisphere, from the Arc ...
-dominated
woodland A woodland () is, in the broad sense, land covered with trees, or in a narrow sense, synonymous with wood (or in the U.S., the '' plurale tantum'' woods), a low-density forest forming open habitats with plenty of sunlight and limited shade (see ...
occurs on rugged, stony
uplands Upland or Uplands may refer to: Geography *Hill, an area of higher land, generally *Highland, an area of higher land divided into low and high points *Upland and lowland, conditional descriptions of a plain based on elevation above sea level *I ...
. The mountain ranges are covered in mountain sagebrush, Idaho fescue,
Douglas-fir The Douglas fir (''Pseudotsuga menziesii'') is an evergreen conifer species in the pine family, Pinaceae. It is native to western North America and is also known as Douglas-fir, Douglas spruce, Oregon pine, and Columbian pine. There are three va ...
,
subalpine Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures fall as elevation increases, causing the ecosystem to stratify. This stratification is a crucial f ...
forests, or
aspen Aspen is a common name for certain tree species; some, but not all, are classified by botanists in the section ''Populus'', of the '' Populus'' genus. Species These species are called aspens: *'' Populus adenopoda'' – Chinese aspen (C ...
. Today, most of the region is used for
livestock Livestock are the domesticated animals raised in an agricultural setting to provide labor and produce diversified products for consumption such as meat, eggs, milk, fur, leather, and wool. The term is sometimes used to refer solely to ani ...
grazing In agriculture, grazing is a method of animal husbandry whereby domestic livestock are allowed outdoors to roam around and consume wild vegetations in order to convert the otherwise indigestible (by human gut) cellulose within grass and ot ...
.
Dryland Drylands are defined by a scarcity of water. Drylands are zones where precipitation is balanced by evaporation from surfaces and by transpiration by plants (evapotranspiration). The United Nations Environment Program defines drylands as tropical ...
and
irrigated Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow crops, landscape plants, and lawns. Irrigation has been a key aspect of agriculture for over 5,000 years and has been develo ...
cropland Agricultural land is typically land ''devoted to'' agriculture, the systematic and controlled use of other forms of lifeparticularly the rearing of livestock and production of cropsto produce food for humans. It is generally synonymous with bot ...
are found in some areas, but in general the
soil Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former ...
s are less suitable for
agriculture Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people ...
than those in the
Columbia Plateau The Columbia Plateau is a geologic and geographic region that lies across parts of the U.S. states of Washington, Oregon, and Idaho. It is a wide flood basalt plateau between the Cascade Range and the Rocky Mountains, cut through by the Col ...
and the Snake River Plain ecoregions. Most public lands in the region are managed by the
Bureau of Land Management The Bureau of Land Management (BLM) is an agency within the United States Department of the Interior responsible for administering federal lands. Headquartered in Washington DC, and with oversight over , it governs one eighth of the country's ...
. The Northern Basin and Range ecoregion has been subdivided into fourteen Level IV ecoregions, as described below. Level IV mapping is not yet complete in California, and the information below includes only the sections in Oregon, Idaho, Nevada, and Utah.


Level IV ecoregions


Dissected High Lava Plateau (80a)

The Dissected High Lava Plateau ecoregion is a broad to gently rolling
basalt Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90 ...
plateau In geology and physical geography, a plateau (; ; ), also called a high plain or a tableland, is an area of a highland consisting of flat terrain that is raised sharply above the surrounding area on at least one side. Often one or more sides ...
cut by deep, sheer-walled
canyon A canyon (from ; archaic British English spelling: ''cañon''), or gorge, is a deep cleft between escarpments or cliffs resulting from weathering and the erosive activity of a river over geologic time scales. Rivers have a natural tendency to cu ...
s, with perennial and intermittent streams draining to the Snake River. Elevation varies from 4,000 to 7,300 feet (1,219 to 2,225 m). The region is less wooded, lower, and more arid than neighboring subregions in the Northern Basin and Range. It differs from sagebrush-dominated regions in the Central Basin and Range in having higher
precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. ...
and colder winters. Potential natural vegetation is mostly sagebrush steppe; Wyoming big sagebrush and
black sagebrush Black sagebrush is a common name for several flowering plants native to the western United States and may refer to: *''Artemisia arbuscula'' *''Artemisia nova ''Artemisia nova'' is a North American species of sagebrush, known by the common name ...
are abundant, as well as Douglas rabbitbrush, Idaho fescue,
bluebunch wheatgrass ''Pseudoroegneria spicata'' is a species of grass known by the common name bluebunch wheatgrass. This native western North American perennial bunchgrass is also known by the scientific synonyms ''Elymus spicatus'' and ''Agropyron spicatum''. The g ...
,
western wheatgrass ''Pascopyrum'' is a monotypic genus of grass containing the sole species ''Pascopyrum smithii'', which is known by the common names western wheatgrass and red-joint wheatgrass, after the red coloration of the nodes. It is native to North America ...
, Thurber's needlegrass, bottlebrush squirreltail, Great Basin wildrye, Sandberg's bluegrass, Indian ricegrass, and
cheatgrass ''Bromus tectorum'', known as downy brome, drooping brome or cheatgrass, is a winter annual grass native to Europe, southwestern Asia, and northern Africa, but has become invasive in many other areas. It now is present in most of Europe, south ...
. Juniper- pinyon woodlands grow on rocky and gravelly uplands.
Understory In forestry and ecology, understory (American English), or understorey (Commonwealth English), also known as underbrush or undergrowth, includes plant life growing beneath the forest canopy without penetrating it to any great extent, but abo ...
species are denser and biological soil crusts tend to be more extensive and in better condition than at similar elevations in the Central Basin and Range. Cheatgrass has replaced depleted
bunchgrass Tussock grasses or bunch grasses are a group of grass species in the family Poaceae. They usually grow as singular plants in clumps, tufts, hummocks, or bunches, rather than forming a sod or lawn, in meadows, grasslands, and prairies. As perennial ...
es in
overgrazed Overgrazing occurs when plants are exposed to intensive grazing for extended periods of time, or without sufficient recovery periods. It can be caused by either livestock in poorly managed agricultural applications, game reserves, or nature rese ...
areas. One of the largest Northern Basin and Range subregions, the Dissected High Lava Plateau covers in Idaho, in Oregon, in Nevada, and in Utah, including much of the
Owyhee Desert The Owyhee Desert ecoregion, within the deserts and xeric shrublands biome, is in the Northwestern United States. The Owyhee Uplands Byway passes through the desert. Geography An arid region of canyons, volcanic rock, sagebrush and grass makes u ...
. It is primarily used for
rangeland Rangelands are grasslands, shrublands, woodlands, wetlands, and deserts that are grazed by domestic livestock or wild animals. Types of rangelands include tallgrass and shortgrass prairies, desert grasslands and shrublands, woodlands, sava ...
and
wildlife habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...
. Contiguous areas in California have not been mapped yet.


Semiarid Hills and Low Mountains (80b)

The Semiarid Hills and Low Mountains ecoregion is higher and more rugged than the sagebrush plains and basins of neighboring regions. It is composed of
unglaciated A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as ...
mountain slopes, hills, and alluvial fans at an elevation of 4,600 to 9,000 feet (1,402 to 2,743 m). The region is covered by mountain big sagebrush, low sagebrush, and associated grasses and understory plants, including bluebunch wheatgrass, Sandberg bluegrass, Great Basin wildrye, Indian ricegrass, cheatgrass, Idaho fescue, needle-and-thread grass,
snowberry ''Symphoricarpos'', commonly known as the snowberry, waxberry, or ghostberry, is a small genus of about 15 species of deciduous shrubs in the honeysuckle family, Caprifoliaceae. With the exception of the Chinese coralberry, '' S. sinensis'', whi ...
, and
serviceberry ''Amelanchier'' ( ), also known as shadbush, shadwood or shadblow, serviceberry or sarvisberry (or just sarvis), juneberry, saskatoon, sugarplum, wild-plum or chuckley pear,A Digital Flora of Newfoundland and Labrador Vascular Plants/ref> is a g ...
. Scattered juniper woodlands grow on shallow and rocky soils. These hills represent the northern limit for both pinyon and
Utah juniper ''Juniperus osteosperma'' (Utah juniper; syn. ''J. utahensis'') is a shrub or small tree native to the southwestern United States. Description The plant reaches , rarely to 9 m, tall. The shoots are fairly thick compared to most junipers, in ...
;
western juniper ''Juniperus occidentalis'', known as the western juniper, is a shrub or tree native to the Western United States, growing in mountains at altitudes of and rarely down to . It is listed as Least Concern on the IUCN Red List because it is a wides ...
replaces them to the west and north. Groves of aspen grow on alluvial fans and along stream networks, with some
lodgepole pine ''Pinus contorta'', with the common names lodgepole pine and shore pine, and also known as twisted pine, and contorta pine, is a common tree in western North America. It is common near the ocean shore and in dry montane forests to the subalpin ...
and Douglas-fir. Geyer willow and Booth willow are also present in
riparian areas A riparian zone or riparian area is the interface between land and a river or stream. Riparian is also the proper nomenclature for one of the terrestrial biomes of the Earth. Plant habitats and communities along the river margins and banks ar ...
. The region includes
stream A stream is a continuous body of surface water flowing within the bed and banks of a channel. Depending on its location or certain characteristics, a stream may be referred to by a variety of local or regional names. Long large streams ...
s that have been designated for protection as critical or high priority
habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...
for
Yellowstone cutthroat trout The Yellowstone cutthroat trout (''Oncorhynchus clarkii bouvieri'') is a subspecies of the cutthroat trout (''Oncorhynchus clarkii''). It is a freshwater fish in the salmon family (family Salmonidae). Native only to a few U.S. states, their ...
and other fish. Water quality has been lightly to moderately degraded by human activities, such as historic
gold mining Gold mining is the extraction of gold resources by mining. Historically, mining gold from alluvial deposits used manual separation processes, such as gold panning. However, with the expansion of gold mining to ores that are not on the surface, ...
and livestock grazing, which is the primary land use today. The ecoregion covers in Idaho, in Nevada, and in Utah, including
Shoshone The Shoshone or Shoshoni ( or ) are a Native American tribe with four large cultural/linguistic divisions: * Eastern Shoshone: Wyoming * Northern Shoshone: southern Idaho * Western Shoshone: Nevada, northern Utah * Goshute: western Utah, easte ...
and Bannock land on the
Fort Hall Indian Reservation The Fort Hall Reservation is a Native American reservation of the federally recognized Shoshone- Bannock Tribes (Shoshoni language: Pohoko’ikkateeCrum, B., Crum, E., & Dayley, J. P. (2001). Newe Hupia: Shoshoni Poetry Songs. University Press ...
and public land within the Sawtooth and Caribou-Targhee national forests.


High Elevation Forests and Shrublands (80c)

The High Elevation Forests and Shrublands ecoregion is composed of steep, rugged, unglaciated mountains with cold winters, at an elevation of 6,000 to 9,900 feet (1,829 to 3,018 m). It is characterized by a mix of
conifer Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All ext ...
s, mountain brush, and sagebrush grassland. North-facing slopes may support Douglas-fir, lodgepole pine, subalpine conifers, aspen, and snowberry. South-facing slopes may support mountain big sagebrush, serviceberry, snowberry, Idaho fescue, chokecherry, mountain brome, bluegrass, and bluebunch wheatgrass. Open grassland grows on wide
ridge A ridge or a mountain ridge is a geographical feature consisting of a chain of mountains or hills that form a continuous elevated crest for an extended distance. The sides of the ridge slope away from the narrow top on either side. The line ...
tops.
Engelmann spruce ''Picea engelmannii'', with the common names Engelmann spruce, white spruce, mountain spruce, and silver spruce, is a species of spruce native to western North America. It is mostly a high-altitude mountain tree but also appears in watered canyon ...
and
subalpine fir ''Abies lasiocarpa'', the subalpine fir or Rocky Mountain fir, is a western North American fir tree. Description ''Abies lasiocarpa'' is a medium-sized evergreen conifer with a very narrow conic crown, growing to tall, exceptionally , with a t ...
may be found in upper
canyon A canyon (from ; archaic British English spelling: ''cañon''), or gorge, is a deep cleft between escarpments or cliffs resulting from weathering and the erosive activity of a river over geologic time scales. Rivers have a natural tendency to cu ...
s. The region covers in southeastern Idaho and in northwestern Utah, including land within the Sawtooth and Caribou-Targhee national forests.


Pluvial Lake Basins (80d)

The Pluvial Lake Basins ecoregion contained vast
lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...
s during the Pleistocene epoch that have now mostly disappeared. It is characterized by gently sloping, internally drained basins with lake terraces, playas, beach plains,
stream terrace Fluvial terraces are elongated terraces that flank the sides of floodplains and fluvial valleys all over the world. They consist of a relatively level strip of land, called a "tread", separated from either an adjacent floodplain, other fluvial te ...
s, intermittent lakes, fan skirts, and cool springs. Elevation varies from 4,200 to 6,200 feet (1,280 to 1,890 m). Some basin floor playas collect and
evaporate Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. High concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when humi ...
water seasonally, but not as extensively as the High Desert Wetlands. Dry lake beds near the
Cascade Mountains The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, a ...
have a significant layer of
volcanic ash Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, created during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used to refer ...
.
Greasewood Greasewood is a common name shared by several plants: * ''Adenostoma fasciculatum'' is a plant with white flowers that is native to Oregon, Nevada, California, and northern Baja California. This shrub is one of the most widespread plants of the ...
, inland saltgrass, and
seepweed __NOTOC__ ''Suaeda'' is a genus of plants also known as seepweeds and sea-blites. Most species are confined to saline or alkaline soil habitats, such as coastal salt-flats and tidal wetlands. Many species have thick, succulent leaves, a character ...
grow in
alkaline soil Alkali, or Alkaline, soils are clay soils with high pH (greater than 8.5), a poor soil structure and a low infiltration capacity. Often they have a hard calcareous layer at 0.5 to 1 metre depth. Alkali soils owe their unfavorable physico ...
s. Better drained, less alkaline soils are dominated by Wyoming big sagebrush and basin big sagebrush, with rubber rabbitbrush, Great Basin wildrye, bottlebrush squirreltail, Indian ricegrass, Sandberg's bluegrass, Thurber's needlegrass, and cheatgrass. The land is used for rangeland and sprinkler-irrigated
alfalfa Alfalfa () (''Medicago sativa''), also called lucerne, is a perennial flowering plant in the legume family Fabaceae. It is cultivated as an important forage crop in many countries around the world. It is used for grazing, hay, and silage, as ...
farming. The region covers in Oregon and in Nevada.


High Desert Wetlands (80e)

The nearly level High Desert Wetlands ecoregion consists of high desert lakes and surrounding
wetland A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (Anoxic waters, anoxic) processes prevailing, especially in t ...
s that provide critical habitat for nesting and migratory birds and associated upland birds and mammals. Elevation varies from 4,000 to 5,200 feet (1,219 to 1,646 m). The fine-textured soils are poorly drained, and basins collect water seasonally. Although water levels fluctuate from year to year, lakes and wetlands in this region hold water more consistently than on the coarser, better drained soils of the Pluvial Lake Basins.
Sedges The Cyperaceae are a family of graminoid (grass-like), monocotyledonous flowering plants known as sedges. The family is large, with some 5,500 known species described in about 90 genera, the largest being the "true sedges" genus ''Carex'' wit ...
, rushes, black greasewood,
tufted hairgrass ''Deschampsia cespitosa'', commonly known as tufted hairgrass or tussock grass, is a perennial tufted plant in the grass family Poaceae. Distribution of this species is widespread including the eastern and western coasts of North America, parts o ...
, mat muhly, meadow barley, creeping wildrye, and Nevada bluegrass occur in wetter areas. Drier areas support basin big sagebrush, Wyoming big sagebrush, silver sagebrush, bluebunch wheatgrass, basin wildrye, Idaho fescue, Thurber's needlegrass, and cheatgrass. The region covers in Oregon, including the
Malheur National Wildlife Refuge Malheur National Wildlife Refuge is a National Wildlife Refuge located roughly south of the city of Burns in Oregon's Harney Basin. Administered by the United States Fish and Wildlife Service, the refuge area is roughly T-shaped with the southe ...
and land surrounding
Malheur Lake Malheur Lake is one of the lakes in the Malheur National Wildlife Refuge in Harney County in the U.S. state of Oregon. Located about southeast of Burns, the lake is marsh fed by the Donner und Blitzen River from the south and the Silvies Rive ...
, Paulina Marsh, Summer Lake,
Lake Abert Lake Abert (also known as Abert Lake) is a large, shallow, alkali lake in Lake County, Oregon, United States. It is approximately long and wide at its widest point. It is located northeast of the small, unincorporated community of Valley Fal ...
, and the Warner Lakes. It also includes in Idaho and in Nevada, on and around the
Duck Valley Indian Reservation The Duck Valley Indian Reservation () was established in the 19th century for the federally recognized Shoshone- Paiute Tribe. It is isolated in the high desert of the western United States, and lies on the state line, the 42nd parallel, betwee ...
.


Owyhee Uplands and Canyons (80f)

The Owyhee Uplands and Canyons ecoregion is a sagebrush steppe containing deep river canyons, barren
lava field Lava fields are large, mostly flat areas of surface or subaquatic lava flows. Such features are generally composed of highly fluid basalt lava, and can extend for tens or hundreds of miles across the underlying terrain. Morphology and str ...
s,
badlands Badlands are a type of dry terrain where softer sedimentary rocks and clay-rich soils have been extensively eroded."Badlands" in ''Chambers's Encyclopædia''. London: George Newnes, 1961, Vol. 2, p. 47. They are characterized by steep slopes, mi ...
, and
tuffaceous Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock c ...
outcrop An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth. Features Outcrops do not cover the majority of the Earth's land surface because in most places the bedrock or superficia ...
s that are riddled by
cave A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word ''cave'' can refer to smaller openings such as sea ...
s. Elevation varies from 2,500 to 6,600 feet (762 to 2,012 m). Although the region's climate and vegetation are similar to the Dissected High Lava Plateau, its
lithology The lithology of a rock unit is a description of its physical characteristics visible at outcrop, in hand or core samples, or with low magnification microscopy. Physical characteristics include colour, texture, grain size, and composition. Li ...
is more varied, stream density is higher, and water availability is greater. These attributes, combined with its remote location, make the region a particularly valuable refuge for wildlife. The steppe is characterized by Wyoming big sagebrush, basin big sagebrush, Douglas rabbitbrush, bluebunch wheatgrass, Idaho fescue, bottlebrush squirreltail, Sandberg's bluegrass, and cheatgrass. Rocky areas support scattered western juniper. It is mostly used for rangeland and wildlife habitat, with some hay and small grain farming. Cheatgrass has replaced depleted bunchgrasses in overgrazed areas. The region covers in Oregon and in Idaho, including
Lake Owyhee Owyhee Reservoir or Owyhee Lake is a reservoir on the Owyhee River in Malheur County, Oregon, United States. Located in far Eastern Oregon near the Idaho border, the reservoir is Oregon's longest at . The lake is home to several species of fish, ...
and the Owyhee, Malheur, and
Succor In international relations, aid (also known as international aid, overseas aid, foreign aid, economic aid or foreign assistance) is – from the perspective of governments – a voluntary transfer of resources from one country to another. A ...
drainages.


High Lava Plains (80g)

The High Lava Plains ecoregion is a vast, nearly level to undulating sagebrush steppe containing scattered
volcanic cone Volcanic cones are among the simplest volcanic landforms. They are built by ejecta from a volcanic vent, piling up around the vent in the shape of a cone with a central crater. Volcanic cones are of different types, depending upon the nature and ...
s and
butte __NOTOC__ In geomorphology, a butte () is an isolated hill with steep, often vertical sides and a small, relatively flat top; buttes are smaller landforms than mesas, plateaus, and tablelands. The word ''butte'' comes from a French word me ...
s. Elevation varies from 4,200 to 6,800 feet (1,280 to 2,073 m). The region is similar to the Dissected High Lava Plateau in its
physiography Physical geography (also known as physiography) is one of the three main branches of geography. Physical geography is the branch of natural science which deals with the processes and patterns in the natural environment such as the atmosphere, h ...
, climate, and vegetation, but, unlike the plateau, it is internally drained. As a result, it lacks
anadromous fish Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousan ...
runs. It also differs from the plateau in having numerous intermittent lakes on the impermeable
volcanic A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plat ...
bedrock In geology, bedrock is solid rock that lies under loose material ( regolith) within the crust of Earth or another terrestrial planet. Definition Bedrock is the solid rock that underlies looser surface material. An exposed portion of be ...
. Vegetation on the steppe includes Wyoming big sagebrush, low sagebrush, mountain big sagebrush, Lahontan sagebrush, bluebunch wheatgrass, Sandberg's bluegrass, Thurber's needlegrass, bottlebrush squirreltail, and Idaho fescue. Silver sagebrush, creeping wildrye, and mat muhly are found in depressions. Shallow and rocky soils support scattered western juniper. The federally threatened Warner sucker fish lives in permanent, shallow, weedy lakes and spawns in Nevada's Twelvemile Creek. The Wall Canyon area supports a unique fish species, the Wall Canyon
sucker Sucker may refer to: General use * Lollipop or sucker, a type of confection * Sucker (slang), a slang term for a very gullible person * Hard candy ** Cough drop ** Mint (candy) Biology * Sucker (botany), a term for a shoot that arises undergro ...
. Higher elevations once supported Lahontan cutthroat trout but water availability limits their present distribution. The largest of the Northern Basin and Range subregions, the High Lava Plains covers in Oregon and in Nevada, featuring a variety of land uses, including rangeland, wildlife habitat, irrigated
pastureland Pasture (from the Latin ''pastus'', past participle of ''pascere'', "to feed") is land used for grazing. Pasture lands in the narrow sense are enclosed tracts of farmland, grazed by domesticated livestock, such as horses, cattle, sheep, or ...
and
cropland Agricultural land is typically land ''devoted to'' agriculture, the systematic and controlled use of other forms of lifeparticularly the rearing of livestock and production of cropsto produce food for humans. It is generally synonymous with bot ...
, historic gold and
silver mines Silver mining is the extraction of silver from minerals, starting with mining. Because silver is often found in intimate combination with other metals, its extraction requires elaborate technologies. In 2008, ca.25,900 metric tons were consumed ...
, and active opal mines and clay
quarries A quarry is a type of open-pit mine in which dimension stone, rock, construction aggregate, riprap, sand, gravel, or slate is excavated from the ground. The operation of quarries is regulated in some jurisdictions to reduce their envir ...
. It contains the
Sheldon National Wildlife Refuge The Sheldon National Wildlife Refuge is a national wildlife refuge on the northern border of the U.S. state of Nevada. A very small part extends northward into Oregon. It is managed by the United States Fish and Wildlife Service (USFWS) as the Ne ...
and lower elevations in the
Hart Mountain National Antelope Refuge Hart Mountain National Antelope Refuge is a National Wildlife Refuge on Hart Mountain in southeastern Oregon, which protects more than and more than 300 species of wildlife, including pronghorn, bighorn sheep, mule deer, sage grouse, and Grea ...
. Contiguous areas in California have not been mapped yet.


Saltbush-Dominated Valleys (80h)

The Saltbush-Dominated Valleys ecoregion, externally drained by the Snake River, is composed of gently sloping valley bottoms and alluvial fans dominated by salt-tolerant vegetation that distinguishes it from the sagebrush steppe of surrounding regions. Elevation varies from 4,500 to 6,000 feet (1,372 to 1,829 m). Light-colored soils with high salt and alkali content are common; they are dry for extended periods and may be leached of salt by irrigation water. Potential natural vegetation is mostly saltbush-greasewood, featuring Nuttall sagebrush, squirreltail,
shadscale ''Atriplex confertifolia'', the shadscale or spiny saltbush, is a species of evergreen shrub in the family Amaranthaceae, which is native to the western United States and northern Mexico. Description The height of ''Atriplex confertifolia'' vari ...
,
winterfat ''Krascheninnikovia'' is a genus of flowering plants in the subfamily Chenopodioideae of the family Amaranthaceae known as winterfat, so-called because it is a nutritious livestock forage. They are known from Eurasia and western North America. Th ...
, and greasewood. Basin sagebrush, Wyoming big sagebrush, bluebunch wheatgrass, needlegrass, bluegrass, and Indian ricegrass are also present. The region covers in Idaho and in Utah, in the
Raft River The Raft River is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed May 4, 2011 tributary of the Snake River located in northern Utah and southern Idaho in the United States. It is part ...
drainage. The land is used primarily for rangeland and irrigated agriculture.


Sagebrush Steppe Valleys (80i)

The Sagebrush Steppe Valleys ecoregion consists of gently sloping, unforested terraces, basin rims, valley bottoms, footslopes, bajadas, and alluvial fans, with an elevation of 4,600 to 6,500 feet (1,403 to 1,981 m). Less rugged than the surrounding hills and mountains, it is dominated by sagebrush grassland and lacks the woodlands, open conifer forests, and saltbush–greasewood vegetation of neighboring regions. The valleys drain mostly to the Snake River and fish assemblages are unlike those of the internally drained basins to the south. Potential vegetation includes bluebunch wheatgrass, Wyoming big sagebrush, cheatgrass, and Sandberg bluegrass. The steppe valleys are less suitable for cropland agriculture and have less available water than many parts of the Snake River Plain, but non-irrigated wheat and barley farming is common. The region covers in southeastern Idaho and across the Utah border.


Semiarid Uplands (80j)

The disjunct Semiarid Uplands ecoregion includes scattered hills, low mountains, volcanic cones, buttes, and rocky outcrops that rise out of the drier Dissected High Lava Plateau and High Lava Plains, as well as midelevation zones in the
Hart Hart often refers to: * Hart (deer) Hart may also refer to: Organizations * Hart Racing Engines, a former Formula One engine manufacturer * Hart Skis, US ski manufacturer * Hart Stores, a Canadian chain of department stores * Hart's Reptile Wo ...
, Steens, Owyhee, Jarbidge, and
Santa Rosa Santa Rosa is the Italian, Portuguese and Spanish name for Saint Rose. Santa Rosa may also refer to: Places Argentina * Santa Rosa, Mendoza, a city * Santa Rosa, Tinogasta, Catamarca * Santa Rosa, Valle Viejo, Catamarca *Santa Rosa, La Pampa * S ...
mountains. Elevation varies from 4,800 to 9,700 feet (1,463 to 2,957 m). Finely textured soils support big sagebrush, low sagebrush, antelope bitterbrush, serviceberry, snowberry, mountain-mahogany, and associated grasses, such as Idaho fescue, bluebunch wheatgrass, Sandberg bluegrass, Nevada bluegrass, Great Basin wildrye, bottlebrush squirreltail, mountain brome, and Thurber needlegrass. Aspen and chokecherry are found in protected snow pockets, with willow and chokecherry in riparian areas. Rockier soils support juniper steppe woodlands. The density and extent of juniper varies over time and is dependent on long-term climate fluctuations, grazing pressure, and fire suppression. Juniper woodland is currently absent in the Jarbidge and Santa Rosa mountains, where mountain brush and scattered aspen groves occupy the woodland zone. Cold water fisheries occur in the moderate to high gradient perennial streams; threatened
bull trout The bull trout (''Salvelinus confluentus'') is a char of the family Salmonidae native to northwestern North America. Historically, ''S. confluentus'' has been known as the " Dolly Varden" (''S. malma''), but was reclassified as a separate speci ...
are found in the
Jarbidge River The Jarbidge River is a , high elevation river in Elko County, Nevada and Owyhee County, Idaho in the United States. The Jarbidge originates as two main forks in the Jarbidge Mountains of northeastern Nevada and then flows through basalt and rh ...
watershed, and limited numbers of
Lahontan cutthroat trout Lahontan cutthroat trout (''Oncorhynchus clarkii henshawi'') is the largest subspecies of cutthroat trout, and the state fish of Nevada. It is one of three subspecies of cutthroat trout that are listed as federally threatened. Natural history ...
are found in the Santa Rosa range. Extensive gold mining operations continue, especially in the mountains near Jarbidge and Tuscacora. The region covers in Nevada, in Oregon, and in Idaho. Public lands include the Humboldt-Toiyabe National Forest and the Hart Mountain National Antelope Refuge.


Partly Forested Mountains (80k)

The Partly Forested Mountains ecoregion occupies the elevational belt above the Semiarid Uplands on the Jarbidge,
Independence Independence is a condition of a person, nation, country, or state in which residents and population, or some portion thereof, exercise self-government, and usually sovereignty, over its territory. The opposite of independence is the stat ...
, Owyhee, and Steens mountains, from 6,500 to 10,900 feet (1,981 to 3,322 m). These are partially glaciated, high, rugged mountains with glacial features including
moraine A moraine is any accumulation of unconsolidated debris ( regolith and rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice sh ...
s,
cirque A (; from the Latin word ') is an amphitheatre-like valley formed by glacial erosion. Alternative names for this landform are corrie (from Scottish Gaelic , meaning a pot or cauldron) and (; ). A cirque may also be a similarly shaped landf ...
s, and
tarn (lake) A tarn (or corrie loch) is a proglacial mountain lake, pond or pool, formed in a cirque excavated by a glacier. A moraine may form a natural dam below a tarn. Etymology The word is derived from the Old Norse word ''tjörn'' ("a small mount ...
s. Perennial or intermittent, high gradient, cold streams are fed by
snowmelt In hydrology, snowmelt is surface runoff produced from melting snow. It can also be used to describe the period or season during which such runoff is produced. Water produced by snowmelt is an important part of the annual water cycle in many p ...
and springs, supporting federally threatened bull trout and Lahontan cutthroat trout in Nevada.
Riffle A riffle is a shallow landform in a flowing channel. Colloquially, it is a shallow place in a river where water flows quickly past rocks. However, in geology a riffle has specific characteristics. Topographic, sedimentary and hydraulic indica ...
segments have cobble or
boulder In geology, a boulder (or rarely bowlder) is a rock fragment with size greater than in diameter. Smaller pieces are called cobbles and pebbles. While a boulder may be small enough to move or roll manually, others are extremely massive. In ...
substrates. Annual precipitation is sufficient to support a Great Basin pine forest community of Douglas-fir, subalpine fir,
ponderosa pine ''Pinus ponderosa'', commonly known as the ponderosa pine, bull pine, blackjack pine, western yellow-pine, or filipinus pine is a very large pine tree species of variable habitat native to mountainous regions of western North America. It is the ...
, and
limber pine ''Pinus flexilis'', the limber pine, is a species of pine tree-the family Pinaceae that occurs in the mountains of the Western United States, Mexico, and Canada. It is also called Rocky Mountain white pine. A limber pine in Eagle Cap Wildernes ...
, with
whitebark pine ''Pinus albicaulis'', known by the common names whitebark pine, white bark pine, white pine, pitch pine, scrub pine, and creeping pine, is a conifer tree native to the mountains of the western United States and Canada, specifically subalpine ...
near the
tree line The tree line is the edge of the habitat at which trees are capable of growing. It is found at high elevations and high latitudes. Beyond the tree line, trees cannot tolerate the environmental conditions (usually cold temperatures, extreme snow ...
, and aspen stands in riparian
meadow A meadow ( ) is an open habitat, or field, vegetated by grasses, herbs, and other non- woody plants. Trees or shrubs may sparsely populate meadows, as long as these areas maintain an open character. Meadows may be naturally occurring or arti ...
s, moist
draw Draw, drawing, draws, or drawn may refer to: Common uses * Draw (terrain), a terrain feature formed by two parallel ridges or spurs with low ground in between them * Drawing (manufacturing), a process where metal, glass, or plastic or anything ...
s, and wet depressions. The understory features low juniper, mountain big sagebrush, mountain brush, serviceberry, snowberry, mountain-mahogany, Idaho fescue, sheep fescue, rough fescue, bottlebrush squirreltail, prairie lupine, mountain brome, bluebunch wheatgrass, and Sandberg bluegrass. Small areas of
tundra In physical geography, tundra () is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. The term ''tundra'' comes through Russian (') from the Kildin Sámi word (') meaning "uplands", "treeless mou ...
and
alpine meadow Alpine tundra is a type of natural region or biome that does not contain trees because it is at high elevation, with an associated harsh climate. As the latitude of a location approaches the poles, the threshold elevation for alpine tundra gets ...
s are found at the highest elevations. On Steens Mountain, above the juniper woodland zone of the Semirarid Uplands, the landscape is almost treeless; broad areas of mountain big sagebrush alternate with scattered groves of aspen. Alpine areas on Steens Mountain were seriously eroded following intense grazing by domestic
sheep Sheep or domestic sheep (''Ovis aries'') are domesticated, ruminant mammals typically kept as livestock. Although the term ''sheep'' can apply to other species in the genus '' Ovis'', in everyday usage it almost always refers to domesticate ...
in the late 19th century. The region covers in Nevada, in Oregon, and in Idaho, and contains the
Jarbidge Wilderness The Jarbidge Wilderness is a wilderness area located in the Jarbidge Mountains of northern Elko County in northeastern Nevada, United States. It is contained within the Jarbidge Ranger District of the Humboldt-Toiyabe National Forest. "Jarbi ...
in the Humboldt-Toiyabe National Forest.


Salt Shrub Valleys (80l)

The Salt Shrub Valleys ecoregion is composed of arid basins formerly inundated by Pleistocene lakes. Elevation varies from 3,500 to 5,200 feet (1,067 to 1,585 m) The nearly flat to gently sloping basins and playas are poorly drained, have a high
water table The water table is the upper surface of the zone of saturation. The zone of saturation is where the pores and fractures of the ground are saturated with water. It can also be simply explained as the depth below which the ground is saturated. T ...
, and retain water seasonally. They are flanked by bajadas and alluvial fans. The region also contains wetlands,
hot spring A hot spring, hydrothermal spring, or geothermal spring is a spring produced by the emergence of geothermally heated groundwater onto the surface of the Earth. The groundwater is heated either by shallow bodies of magma (molten rock) or by circ ...
s, terraces,
dune A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, f ...
s, and a few hills. Soils, climate, and vegetation are transitional to the Central Basin and Range to the south. Characteristically, the basin floors have strongly saline and very alkaline soils that support black greasewood, inland saltgrass, bud sagebrush, shadscale, alkali sacaton, rushes, basin wildrye, bottlebrush squirreltail, and cheatgrass. Alluvial fans and hills support Wyoming big sagebrush, spiny hopsage, rabbitbrush, Thurber needlegrass, Indian ricegrass, Sandberg bluegrass, and bottlebrush squirreltail. The region covers in Oregon and in Nevada, including a small part of the Sheldon National Wildlife Refuge.


Barren Playas (80m)

The Barren Playas ecoregion includes the playas and sand dunes of Summer Lake, Silver Lake, and the
Alvord Desert The Alvord Desert is a desert located in Harney County, in southeastern Oregon in the Western United States. It is roughly southeast of Steens Mountain. The Alvord Desert is a dry lake bed and averages of rain a year. Two mountain ranges ...
, three of the most arid areas in Oregon. Elevation varies from 4,500 to 5,000 feet (1,372 to 1,524 m), with a local
relief Relief is a sculptural method in which the sculpted pieces are bonded to a solid background of the same material. The term '' relief'' is from the Latin verb ''relevo'', to raise. To create a sculpture in relief is to give the impression that th ...
of less than . On the playas, lake levels and salinity fluctuate seasonally and yearly. Playas are ponded during wet intervals and
eroded Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is disti ...
by wind when dry. Surface material is clayey, saline, alkaline, and poorly drained. Sand dunes and mud flats occur. This region is mostly barren; vegetation, where present, is sparse and composed of very salt-tolerant plants, such as alkali sacaton and black greasewood. The region covers in Oregon. It is nonarable and is used for recreation and migratory bird habitat.


Gallery


Flora

Image:Pinus flexilis male cones.jpg,
Limber pine ''Pinus flexilis'', the limber pine, is a species of pine tree-the family Pinaceae that occurs in the mountains of the Western United States, Mexico, and Canada. It is also called Rocky Mountain white pine. A limber pine in Eagle Cap Wildernes ...
Image:Juniperus osteosperma 1.jpg,
Utah juniper ''Juniperus osteosperma'' (Utah juniper; syn. ''J. utahensis'') is a shrub or small tree native to the southwestern United States. Description The plant reaches , rarely to 9 m, tall. The shoots are fairly thick compared to most junipers, in ...
Image:Prunus virginiana.jpg, Western chokecherry leaves and berries Image:Sagebrush with shattered trunk.jpg,
Big sagebrush ''Artemisia tridentata'', commonly called big sagebrush,MacKay, Pam (2013), ''Mojave Desert Wildflowers'', 2nd ed., , p. 264. Great Basin sagebrush or (locally) simply sagebrush, is an aromatic shrub from the family Asteraceae, which grows in ari ...
Image:Elymus elymoides NPS-1.jpg, Bottlebrush squirreltail Image:Needleandthreadgrass2.jpg, Needle-and-thread grass Image:Rabbitbrush.jpg, Rubber rabbitbrush Image:Grayia spinosa 1.jpg, Spiny hopsage


Fauna

Image:Pinyonjay.jpg,
Pinyon jay The pinyon jay (''Gymnorhinus cyanocephalus'') is a species of jay, and is the only member of the genus ''Gymnorhinus''. Native to Western North America, the species ranges from central Oregon to northern Baja California, and eastward as far as ...
, found in juniper-pinyon woodlands Image:Yellowstone Cutthroat Trout.jpg,
Yellowstone cutthroat trout The Yellowstone cutthroat trout (''Oncorhynchus clarkii bouvieri'') is a subspecies of the cutthroat trout (''Oncorhynchus clarkii''). It is a freshwater fish in the salmon family (family Salmonidae). Native only to a few U.S. states, their ...
in the Snake River system Image:American Avocet2.jpg,
American avocet The American avocet (''Recurvirostra americana'') is a large wader in the avocet and stilt family, Recurvirostridae, that is found in North America. It spends much of its time foraging in shallow water or on mud flats, often sweeping its bill ...
at Summer Lake Image:SageGrouse21.jpg,
Sage grouse Sage-grouse are grouse belonging to the bird genus ''Centrocercus.'' The genus includes two species: the Gunnison grouse (''Centrocercus minimus'') and the greater sage-grouse (''Centrocercus urophasianus''). These birds are distributed throug ...
in shrub-steppe habitat


Landscapes

Image:2013-07-07 15 41 55 Great Basin Sagebrush steppe along Three Creek Road, in Owyhee County, southwestern Idaho.jpg, Sagebrush-Steppe in south-central Idaho along Three Creek Road Image:Hart Mountain National Antelope Refuge.jpg,
Bunchgrass Tussock grasses or bunch grasses are a group of grass species in the family Poaceae. They usually grow as singular plants in clumps, tufts, hummocks, or bunches, rather than forming a sod or lawn, in meadows, grasslands, and prairies. As perennial ...
es on
Hart Mountain Hart Mountain is a fault-block mountain, in Lake County, Oregon, U.S. It lies about to the east of Lakeview. It is sometimes confused with a mountain range, but is more properly described as a mountain. The two highest peaks are Warner Peak a ...
Image:Alvord Desert sunset.jpg, The cracked playa surface of the
Alvord Desert The Alvord Desert is a desert located in Harney County, in southeastern Oregon in the Western United States. It is roughly southeast of Steens Mountain. The Alvord Desert is a dry lake bed and averages of rain a year. Two mountain ranges ...
Image:AbertRim-cright.jpg, Cheatgrass covers the
fault scarp A fault scarp is a small step or offset on the ground surface where one side of a fault has moved vertically with respect to the other. It is the topographic expression of faulting attributed to the displacement of the land surface by movement a ...
of Abert Rim. Image:2013-07-04 15 37 14 Sagebrush-steppe along U.S. Route 93 in central Elko County in Nevada.jpg, Sagebrush steppe in northeastern
Nevada Nevada ( ; ) is a U.S. state, state in the Western United States, Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. N ...
along US 93


See also

*Ecoregions defined by the EPA and the
Commission for Environmental Cooperation The Commission for Environmental Cooperation (CEC; es, Comisión para la Cooperación Ambiental; french: Commission de coopération environnementale) was established by Canada, Mexico, and the United States to implement the North American Agr ...
: **
List of ecoregions in North America (CEC) This list of ecoregions of North America provides an overview of North American ecoregions designated by the Commission for Environmental Cooperation (CEC) in its North American Environmental Atlas. It should not be confused with Wikipedia articl ...
** List of ecoregions in the United States (EPA) ** List of ecoregions in Oregon *The conservation group
World Wildlife Fund The World Wide Fund for Nature Inc. (WWF) is an international non-governmental organization founded in 1961 that works in the field of wilderness preservation and the reduction of human impact on the environment. It was formerly named the W ...
maintains an alternate classification system: **
List of ecoregions (WWF) The World Wildlife Fund (WWF) identifies terrestrial, marine, freshwater, and ecoregions: *Global 200 * List of terrestrial ecoregions (WWF) 867 terrestrial ecoregions. *List of marine ecoregions (WWF) The following is a list of marine ecoregions ...
**
List of ecoregions in the United States (WWF) The following is a list of ecoregions in the United States as identified by the World Wide Fund for Nature (WWF). The United States is a megadiverse country with a high level of endemism across a wide variety of ecosystems. Terrestrial ecoregi ...
* Colloquial terms for the region: ** Basin and Range (disambiguation) **
Basin and Range Province The Basin and Range Province is a vast physiographic region covering much of the inland Western United States and northwestern Mexico. It is defined by unique basin and range topography, characterized by abrupt changes in elevation, alternating ...


References

{{Ecoregions in Oregon Ecoregions of the United States Ecology of the Great Basin Ecoregions of California Regions of Idaho Regions of Nevada Ecoregions of Oregon Basin and Range Province