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 agency of the United States government tasked with environmental protection matters. President Richard Nixon proposed the establishment of EPA on July 9, 1970; it began operation on De ...

(EPA) in the

U.S. states In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its so ...

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

Idaho Idaho ( ) is a landlocked U.S. state, state in the Pacific Northwest and Mountain states, Mountain West subregions of the Western United States. It borders Montana and Wyoming to the east, Nevada and Utah to the south, and Washington (state), ...

Nevada Nevada ( ; ) is a landlocked state in the Western United States. It borders Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. Nevada is the seventh-most extensive, th ...

Utah Utah is a landlocked state in the Mountain states, Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northea ...

, and

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

. It contains dissected lava plains, rolling

hill A hill is a landform that extends above the surrounding terrain. It often has a distinct summit, and is usually applied to peaks which are above elevation compared to the relative landmass, though not as prominent as Mountain, mountains. Hills ...

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 Semi-arid climate, semiar ...

valley A valley is an elongated low area often running between hills or mountains and typically containing 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 over ...

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 aris ...

s in the northern part of the

Great Basin The Great Basin () is the largest area of contiguous endorheic watersheds, those with no outlets to the ocean, in North America. It spans nearly all of Nevada, much of Utah, and portions of California, Idaho, Oregon, Wyoming, and Baja Californi ...

. Although

arid Aridity is the condition of geographical regions which make up approximately 43% of total global available land area, characterized by low annual precipitation, increased temperatures, and limited water availability.Perez-Aguilar, L. Y., Plata ...

, the

ecoregion An ecoregion (ecological region) is an ecological and geographic area that exists on multiple different levels, defined by type, quality, and quantity of environmental resources. Ecoregions cover relatively large areas of land or water, and c ...

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 geology, geologic feature located primarily within the U.S. state of Idaho. ...

to the north and has more available moisture and a cooler

climate Climate is the long-term weather pattern in a region, 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 meteoro ...

than the Central Basin and Range to the south. Its southern boundary is determined by the highest shoreline of

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

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 temperatur ...

, 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 in the interior Pacific Northwest region of the United States. About long, it is the largest tributary of the Columbia River, which is the largest North American river that empties into the Pacific Ocean. Begin ...

system. The valleys support sagebrush steppe or

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 Aridisols (or desert soils) are a soil order in USDA soil taxonomy. Aridisols (from the Latin ''aridus'', for "dry", and ''solum'') form in an arid or semi-arid climate. Aridisols dominate the deserts and xeric shrublands, which occupy about on ...

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 as far south ...

-dominated

woodland A woodland () is, in the broad sense, land covered with woody plants (trees and shrubs), 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 sunli ...

occurs on rugged, stony uplands. 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 the tallest tree in the Pinaceae family. It is native to western North America and is also known as Douglas-fir, Douglas spruce, Or ...

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 in the Populus sect. Populus, of the ''Populus'' (poplar) genus. Species These species are called aspens: * ''Populus adenopoda'' – Chinese aspen (China, south of ''P. tremula'') * ''Populus da ...

. Today, most of the region is used for

livestock Livestock are the Domestication, domesticated animals that are raised in an Agriculture, agricultural setting to provide labour and produce diversified products for consumption such as meat, Egg as food, eggs, milk, fur, leather, and wool. The t ...

grazing In agriculture, grazing is a method of animal husbandry whereby domestic livestock are allowed outdoors to free range (roam around) and consume wild vegetations in order to feed conversion ratio, convert the otherwise indigestible (by human diges ...

. Dryland and

irrigated Irrigation (also referred to as watering of plants) 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 be ...

cropland are found in some areas, but in general the

soil Soil, also commonly referred to as earth, is a mixture of organic matter, minerals, gases, water, and organisms that together support the life of plants and soil organisms. Some scientific definitions distinguish dirt from ''soil'' by re ...

s are less suitable for

agriculture Agriculture encompasses crop and livestock production, aquaculture, and forestry for food and non-food products. Agriculture was a key factor in the rise of sedentary human civilization, whereby farming of domesticated species created ...

than those in the

Columbia Plateau The Columbia Plateau is an important geology, geologic and geography, geographic region that lies across parts of the U.S. states of Washington (state), Washington, Oregon, and Idaho. It is a wide flood basalt plateau between the Cascade Range a ...

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, U.S. federal lands. Headquartered in Washington, D.C., the BLM oversees more than of land, or one ...

. 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 aphanite, 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 planetary surface, surface of a terrestrial ...

plateau In geology and physical geography, a plateau (; ; : plateaus or plateaux), 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. ...

cut by deep, sheer-walled

canyon A canyon (; archaic British English spelling: ''cañon''), gorge or chasm, 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 t ...

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 from clouds due to gravitational pull. The main forms of precipitation include drizzle, rain, rain and snow mixed ("sleet" in Commonwe ...

and colder winters. Potential natural vegetation is mostly sagebrush steppe; Wyoming big sagebrush and black sagebrush are abundant, as well as Douglas rabbitbrush, Idaho fescue, bluebunch wheatgrass, western wheatgrass, Thurber's needlegrass, bottlebrush squirreltail, Great Basin wildrye, Sandberg's bluegrass, Indian ricegrass, and cheatgrass. Juniper- pinyon woodlands grow on rocky and gravelly uplands.

Understory In forestry and ecology, understory (American English), or understorey (English in the Commonwealth of Nations, Commonwealth English), also known as underbrush or undergrowth, includes plant life growing beneath the Canopy (biology), forest ca ...

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 perennia ...

es in overgrazed 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. 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, savanna ...

and

wildlife habitat In ecology, habitat refers to the array of resources, 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 manifestation of its ...

. 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 (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its Ablation#Glaciology, ablation over many years, often cen ...

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'' is a small genus of about 15 species of deciduous shrubs in the family Caprifoliaceae. With the exception of the Chinese coralberry, ''Symphoricarpos sinensis, S. sinensis'', which is indigenous to western China, all species a ...

, and serviceberry. Scattered juniper woodlands grow on shallow and rocky soils. These hills represent the northern limit for both pinyon and Utah juniper; western juniper 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. The region includes

stream A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, a strea ...

s that have been designated for protection as critical or high priority

habitat In ecology, habitat refers to the array of resources, 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 manifestation of its ...

for Yellowstone cutthroat trout 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 by mining. Historically, mining gold from Alluvium, alluvial deposits used manual separation processes, such as gold panning. The expansion of gold mining to ores that are not on the surface has led to mor ...

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 ), also known by the endonym Newe, are an Native Americans in the United States, Indigenous people of the United States with four large cultural/linguistic divisions: * Eastern Shoshone: Wyoming * Northern Shoshon ...

and Bannock land on the

Fort Hall Indian Reservation The Fort Hall Reservation is a Indian reservation, Native American reservation of the federally recognized Shoshone-Bannock people, Bannock Tribes (Shoshoni language: Pohoko’ikkateeCrum, B., Crum, E., & Dayley, J. P. (2001). Newe Hupia: Shosh ...

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 conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a sin ...

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 is a long, narrow, elevated geomorphologic landform, structural feature, or a combination of both separated from the surrounding terrain by steep sides. The sides of a ridge slope away from a narrow top, the crest or ridgecrest, wi ...

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 highly prized for producing distinctive tone wood for acoustic guitars ...

and subalpine fir may be found in upper

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 often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from ...

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 terraces, 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. A high concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when hum ...

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 many of those in the ...

have a significant layer of

volcanic ash Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, produced during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used to r ...

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 grow in

alkaline soil Alkali, or alkaline, soils are clay soils with high Soil pH, 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 ...

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 plant, 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, ...

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 semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...

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; botanists have described some 5,500 known species in about 90 generathe largest being the "true sedges" (genu ...

, rushes, black greasewood, tufted hairgrass, 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 and land surrounding

Malheur Lake Malheur Lake ( ) is one of the lakes in the Malheur National Wildlife Refuge in Harney County, Oregon, Harney County in the U.S. state of Oregon. Located about southeast of Burns, Oregon, Burns, the lake is marsh fed by the Donner und Blitzen ...

, Paulina Marsh, Summer Lake, Lake Abert, 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 A lava field, sometimes called a lava bed, is a large, mostly flat area of lava flows. Such features are generally composed of highly fluid basalt lava, and can extend for tens or hundreds of kilometers across the underlying terrain. Morp ...

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, ...

, and tuffaceous

outcrop An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth and other terrestrial planets. Features Outcrops do not cover the majority of the Earth's land surface because in most p ...

s that are riddled by

cave Caves or caverns are natural voids under the Earth's Planetary surface, surface. Caves often form by the weathering of rock and often extend deep underground. Exogene caves are smaller openings that extend a relatively short distance undergrou ...

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. Lit ...

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 and the Owyhee, Malheur, and Succor 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 ...

s and

butte 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 table (landform), tablelands. The word ''butte'' comes from the French l ...

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 runs. It also differs from the plateau in having numerous intermittent lakes on the impermeable

volcanic A volcano is commonly defined as a vent or fissure 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 fo ...

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 bed ...

. 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. 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 and cropland, historic gold and silver mines, 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 manage their safet ...

. It contains the

Sheldon National Wildlife Refuge The Sheldon National Wildlife Refuge is a United States National Wildlife Refuge, 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 ...

and lower elevations in the Hart Mountain National Antelope Refuge. 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 Mexico, officially the United Mexican States, is a c ...

, winterfat, 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 par ...

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, Steens, Owyhee, Jarbidge, and Santa Rosa 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 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 r ...

watershed, and limited numbers of

Lahontan cutthroat trout Lahontan cutthroat trout'','' ''Oncorhynchus henshawi'',Markle, D. (2018). An interim classification of the cutthroat trout complex, Oncorhynchus clarkii Sensu Lato, with comments on nomenclature. In Trotter P., Bisson P., Schultz L., & Roper B. ...

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 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 status of ...

, 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 (geology), 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 gla ...

cirque A (; from the Latin word ) is an amphitheatre-like valley formed by Glacier#Erosion, glacial erosion. Alternative names for this landform are corrie (from , meaning a pot or cauldron) and ; ). A cirque may also be a similarly shaped landform a ...

s, and

tarn (lake) A tarn (or corrie loch) is a mountain lake, pond or pool, formed in a cirque (or "corrie") 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 mo ...

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 part ...

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 ...

substrate Substrate may refer to: Physical layers *Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached ** Substrate (aquatic environment), the earthy material that exi ...

s. 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 t ...

, and

limber pine ''Pinus flexilis'', the limber pine, is a species of pine tree in 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 Wilder ...

, 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 a habitat at which trees are capable of growing and beyond which they are not. It is found at high elevations and high latitudes. Beyond the tree line, trees cannot tolerate the environmental conditions (usually low ...

, 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 they maintain an open character. Meadows can occur naturally under favourable con ...

s, moist draws, 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, a tundra () is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. There are three regions and associated types of tundra: #Arctic, Arctic, Alpine tundra, Alpine, and #Antarctic ...

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 (: sheep) or domestic sheep (''Ovis aries'') are a domesticated, ruminant mammal 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 d ...

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. "Jarb ...

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 phreatic zone or zone of saturation. The zone of saturation is where the pores and fractures of the ground are saturated with groundwater, which may be fresh, saline, or brackish, depending on the loc ...

, 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 (hydrology), spring produced by the emergence of Geothermal activity, geothermally heated groundwater onto the surface of the Earth. The groundwater is heated either by shallow ...

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, flat ...

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, 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 sculpture, sculptural method in which the sculpted pieces remain attached to a solid background of the same material. The term ''wikt:relief, relief'' is from the Latin verb , to raise (). To create a sculpture in relief is to give ...

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 in 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 Wilder ...

Image:Juniperus osteosperma 1.jpg, Utah juniper Image:Prunus virginiana.jpg, Western chokecherry leaves and berries Image:Sagebrush with shattered trunk.jpg, Big sagebrush 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, found in juniper-pinyon woodlands Image:Yellowstone Cutthroat Trout.jpg, Yellowstone cutthroat trout in the Snake River system Image:American Avocet2.jpg, American avocet 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 perennia ...

es on Hart Mountain Image:Alvord Desert sunset.jpg, The cracked playa surface of the Alvord Desert Image:AbertRim-cright.jpg, Cheatgrass covers the

fault scarp A fault scarp is a small step-like offset of the ground surface in which one side of a fault has shifted vertically in relation to the other. The topographic expression of fault scarps results from the differential erosion of rocks of contrastin ...

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

along US 93

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