Shrub-steppe is a type of low-rainfall natural

grassland A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur natur ...

. While arid, shrub-steppes have sufficient moisture to support a cover of

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

grasses or shrubs, a feature which distinguishes them from

desert A desert is a barren area of landscape where little precipitation occurs and, consequently, living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to denudation. About on ...

s. The primary ecological processes historically at work in shrub-steppe ecosystems are

drought A drought is defined as drier than normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D. Jiang, A. Khan, W. Pokam Mba, D. Rosenfeld, J. Tierney, an ...

and

fire Fire is the rapid oxidation of a material (the fuel) in the exothermic chemical process of combustion, releasing heat, light, and various reaction Product (chemistry), products. At a certain point in the combustion reaction, called the ignition ...

. Shrub-steppe plant species have developed particular adaptations to low annual precipitation and summer drought conditions. Plant adaptations to different

soil moisture Soil moisture is the water content of the soil. It can be expressed in terms of volume or weight. Soil moisture measurement can be based on ''in situ'' probes (e.g., capacitance probes, neutron probes) or remote sensing methods. Water that enters ...

regimes influence their distribution. A frequent fire regime in the shrub-steppe similarly

adds Applied Digital Data Systems (ADDS) was a supplier of video display computer terminals, founded in 1969 by Leeam Lowin and William J. Catacosinos. Lowin simultaneously founded Solid State Data Sciences (SSDS). SSDS was one of the first developers ...

to the patchwork pattern of shrub and grass that characterizes shrub-steppe ecosystems.

North America

2013-07-04 15 37 14 Sagebrush-steppe along U

The shrub-steppes of North America occur in the western United States and western Canada, in the

rain shadow A rain shadow is an area of significantly reduced rainfall behind a mountainous region, on the side facing away from prevailing winds, known as its leeward side. Evaporated moisture from water bodies (such as oceans and large lakes) is carrie ...

between the Cascades and

Sierra Nevada The Sierra Nevada () is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primarily ...

on the west and the

Rocky Mountains The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico in ...

on the east. They extend from south-central

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...

down into south central and south-eastern Washington, eastern

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 ...

, and eastern

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

, and across through

Idaho Idaho ( ) is a 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 Montana and Wyom ...

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 ...

, and

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 it ...

into western

Wyoming Wyoming () is a U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the south ...

and

Colorado Colorado (, other variants) is a state in the Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of t ...

, and down into northern and central

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe , LargestCity = Albuquerque , LargestMetro = Tiguex , OfficialLang = None , Languages = English, Spanish ( New Mexican), Navajo, Ker ...

and northern

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...

. Growth is dominated primarily by low-lying shrubs, such as big sagebrush ('' Artemisia tridentata'') and bitterbrush (''

Purshia tridentata ''Purshia tridentata'', with the common name bitterbrush, is a shrub in the genus '' Purshia'' of the family Rosaceae. It is native to mountainous areas of western North America. Common names include antelope bitterbrush, antelope bush, buc ...

''), with too little rainfall to support the growth of forests, though some trees do occur. Other important plants are

bunchgrasses 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 ...

such as ''

Pseudoroegneria spicata ''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 ...

'', which have historically provided forage for livestock as well as wildlife, but are quickly being replaced by nonnative annual species like cheatgrass (''

Bromus tectorum ''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, southe ...

''), tumble mustard (''

Sisymbrium altissimum ''Sisymbrium altissimum'' is a species of ''Sisymbrium''. The plant is native to the western part of the Mediterranean Basin and is widely naturalized throughout most of the world, including all of North America. After maturity it forms a tumb ...

''), and Russian thistle (''

Salsola kali ''Salsola kali'' was the botanical name for a species of flowering plants in the amaranth family, whose subspecies have been recently reclassified as two separate species in the genus ''Kali'': * ''Kali tragus'', formerly ''Salsola tragus'' or '' ...

''). There is also a suite of animals that call the shrub-steppe home, including

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 through ...

pygmy rabbit The pygmy rabbit (''Brachylagus idahoensis'') is a rabbit species native to the United States. It is also the only native rabbit species in North America to dig its own burrow. The pygmy rabbit differs significantly from species within either the ...

Western rattlesnake Western rattlesnake may refer to: * ''Crotalus oreganus'', a venomous pitviper species found in North America in the western United States, parts of British Columbia and northwestern Mexico * ''Crotalus viridis ''Crotalus viridis'' (Common name ...

, and pronghorn. Historically, much of the shrub-steppe in the state of Washington was referred to as "scabland" because of the deep channels cut into pure basalt rock by cataclysmic floods more than 10,000 years ago (see Channeled Scablands). Major threats to the ecosystem include overgrazing, fires, invasion by nonnative species, development (since much of it is at lower elevations), conversion to cropland, and energy development. Less than 50% of the state of Washington's historic shrub-steppe remains; according to some estimates, only 12 to 15% remains. Shrub-steppe ecoregions of North America include: *

Great Basin shrub steppe The Great Basin Desert is part of the Great Basin between the Sierra Nevada and the Wasatch Range. The desert is a geographical region that largely overlaps the Great Basin shrub steppe defined by the World Wildlife Fund, and the Central Basin a ...

in eastern California, central Nevada, western Utah, and southeastern Idaho. *

Snake–Columbia shrub steppe The Snake–Columbia shrub steppe is an ecoregion defined by the World Wide Fund for Nature (WWF). This ecoregion receives little precipitation because it is within the rain shadow of the Cascade Range. It takes in a western portion of the Colu ...

in south-central Washington state, eastern Oregon, northeastern California, northern Nevada, and Idaho. *

Wyoming Basin shrub steppe The Wyoming Basin shrub steppe ecoregion, within the deserts and xeric shrublands biome, is a shrub steppe in the northwestern United States. Setting This Ecoregion is located almost entirely within the western and central portions of the US s ...

in central Wyoming, reaching into south-central Montana, northeastern Utah, southeastern Idaho, and northwestern Colorado. * Okanagan shrub steppe in the Okanagan Valley in south-central British Columbia, and the southern

Similkameen Valley Similkameen may refer to: * Similkameen Country or Similkameen District, or "the Similkameen", a historical georegion in British Columbia, Canada * Similkameen River, a river that runs through southern British Columbia, discharging into the Okanog ...

in south-central British Columbia and north-central Washington state.

References

External links

U.S. Government article: "Shrub-steppes"
* ttp://wdfw.wa.gov/conservation/research/projects/shrubsteppe/: Washington Dept. of Fish and Game- Species & Ecosystem Science, Shrubsteppe Ecology {{DEFAULTSORT:Shrub-steppe Temperate grasslands, savannas, and shrublands Ecoregions Grasslands

North America

See also

References

External links