The Edwards Plateau is a geographic region forming the crossroads of Central,

South South is one of the cardinal directions or compass points. The direction is the opposite of north and is perpendicular to both west and east. Etymology The word ''south'' comes from Old English ''sūþ'', from earlier Proto-Germanic ''*sunþa ...

and

West Texas West Texas is a loosely defined region in the U.S. state of Texas, generally encompassing the desert climate, arid and semiarid climate, semiarid lands west of a line drawn between the cities of Wichita Falls, Texas, Wichita Falls, Abilene, Texa ...

, United States. It is named in honor of

Haden Edwards Haden Edwards (August 12, 1771 – August 14, 1849) was a Texas settler. Edwards County, Texas on the Edwards Plateau is named for him. In 1825, Edwards received a land grant from the Mexican government, allowing him to settle families in East T ...

. It is bounded by the

Balcones Fault The Balcones Fault or Balcones Fault Zone is an area of largely normal faulting Edwards Aquifer in the U.S. state of Texas that runs roughly from the southwest part of the state near Del Rio to the north-central region near Dallas along Inte ...

to the south and east; the

Llano Uplift The Llano Uplift is a geologically ancient, low geologic dome that is about in diameter and located mostly in Llano, Mason, San Saba, Gillespie, and Blanco counties, Texas. It consists of an island-like exposure of Precambrian igneous and ...

and the

Llano Estacado The Llano Estacado (), sometimes translated into English as the Staked Plains, is a region in the Southwestern United States that encompasses parts of eastern New Mexico and northwestern Texas. One of the largest mesas or tablelands on the North A ...

to the north; and the

Pecos River The Pecos River ( ; ) originates in north-central New Mexico and flows into Texas, emptying into the Rio Grande. Its headwaters are on the eastern slope of the Sangre de Cristo mountain range in Mora County north of Pecos, New Mexico, at an elev ...

and Chihuahuan Desert to the west.

San Angelo San Angelo ( ) is a city in and the county seat of Tom Green County, Texas, United States. Its location is in the Concho Valley, a region of West Texas between the Permian Basin (North America), Permian Basin to the northwest, Chihuahuan Desert ...

Austin Austin refers to: Common meanings * Austin, Texas, United States, a city * Austin (given name), a list of people and fictional characters * Austin (surname), a list of people and fictional characters * Austin Motor Company, a British car manufac ...

San Antonio San Antonio ( ; Spanish for " Saint Anthony") is a city in the U.S. state of Texas and the most populous city in Greater San Antonio. San Antonio is the third-largest metropolitan area in Texas and the 24th-largest metropolitan area in the ...

and Del Rio roughly outline the area. The plateau, especially its southeast portion, is also known as the

Texas Hill Country The Texas Hill Country is a geographic region of Central and South Texas, forming the southeast part of the Edwards Plateau. Given its location, climate, terrain, and vegetation, the Hill Country can be considered the border between the Ame ...

Natural history

The bedrock consists primarily of

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

, with elevations ranging between 100 and 3000 ft. Caves are numerous. The landscape of the plateau is mostly

savanna A savanna or savannah is a mixed woodland-grassland (i.e. grassy woodland) biome and ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach th ...

scattered with trees. It mostly lacks deep soil suitable for farming, though the soil type is fertile

mollisol Mollisol is a soil type which has deep, high organic matter, nutrient-enriched surface soil ( A horizon), typically between 60 and 80 cm (24-31 in) in depth. This fertile surface horizon, called a mollic epipedon, is the defining diagnost ...

, so some

cotton Cotton (), first recorded in ancient India, is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus '' Gossypium'' in the mallow family Malvaceae. The fiber is almost pure ...

, grain

sorghum ''Sorghum bicolor'', commonly called sorghum () and also known as great millet, broomcorn, guinea corn, durra, imphee, jowar, or milo, is a species in the Poaceae, grass genus ''Sorghum (genus), Sorghum'' cultivated for its grain. The grain i ...

, and oats are grown. For the most part, though, the thin soil and rough terrain areas are primarily

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 ...

regions, with cattle, sheep, and goats ( Angora and meat types) predominant. Several rivers cross the region, which generally flow to the south and east through the Texas Hill Country toward the

Gulf of Mexico The Gulf of Mexico () is an oceanic basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by the Gulf Coast of the United States; on the southw ...

; springs occur (in wet years), but permanent surface water supplies are sparse throughout the area, except for man-made reservoirs. The area is well drained; rainwater flows into the

Edwards Aquifer The Edwards Aquifer is one of the most prolific artesian aquifers in the world. Located on the eastern edge of the Edwards Plateau in the U.S. state of Texas, it is the source of drinking water for two million people, and is the primary water su ...

recharge zone at the south of the plateau to feed rivers to the south. Rainfall varies from 15 to 33 inches per year, typically, from northwest to southeast, and the area has a moderate temperature and a reasonably long growing season.

Flora

Trees of the savanna include

Ashe juniper ''Juniperus ashei'' (Ashe juniper, mountain cedar, blueberry juniper, post cedar, or just cedar) is a drought-tolerant evergreen tree, native from northeastern Mexico and the south-central United States to southern Missouri. The largest areas are ...

s (locally called mountain cedar) and

oak An oak is a hardwood tree or shrub in the genus ''Quercus'' of the beech family. They have spirally arranged leaves, often with lobed edges, and a nut called an acorn, borne within a cup. The genus is widely distributed in the Northern Hemisp ...

species, especially plateau live oak and

Texas red oak ''Quercus buckleyi'', commonly known as Texas red oak, Buckley's oak, or Spanish oak is a species of flowering plant. It is endemic to the southern Great Plains of the United States (Oklahoma and Texas). Buckley's oak is smaller and more likely ...

, scattered over grasses such as

little bluestem ''Schizachyrium scoparium'', commonly known as little bluestem or beard grass, is a species of North American prairie grass native to most of the contiguous United States (except California, Nevada, and Oregon) as well as a small area north of t ...

and sideoats grama, a vegetation type historically shaped by droughts and regular fires. Other abundant woody species include Texas mountain-laurel, Texas persimmon,

cedar elm ''Ulmus crassifolia'' Nutt., the Texas cedar elm or simply cedar elm, is a deciduous tree native to south-central North America, mainly in southern and eastern Texas, southern Oklahoma, Arkansas, and Louisiana, with small populations in western M ...

and agarito.

Pecan The pecan ( , , ; ''Carya illinoinensis'') is a species of hickory native to the Southern United States and northern Mexico in the region of the Mississippi River. The tree is cultivated for its seed primarily in the U.S. states of Georgia ( ...

trees are native in floodplains along springs and rivers, which are often lined with stands of baldcypress. The Balcones Fault zone which runs along the southern and eastern edge of the plateau is an ecological demarcation for the ranges of a number of species.

Fauna

Caves of the Edwards Plateau are important habitats for wildlife and for many endemic species. The area is home to some of the largest colonies of bats in the world, including millions of

Mexican free-tailed bat The Mexican free-tailed bat or Brazilian free-tailed bat (''Tadarida brasiliensis'') is a medium-sized bat native to North, Central, and South America and the Caribbean, so named because its tail can be almost half its total length and is not a ...

s. The largest colony of these inhabits

Bracken Cave Bracken Cave is a cave located in southern Comal County, Texas, outside the city of San Antonio. The -wide crescent shaped opening to the cave lies at the bottom of a sinkhole, formed when the roof of the cave collapsed. It is the summer home t ...

near San Antonio, while the

Congress Avenue Bridge The Ann W. Richards Congress Avenue Bridge (formerly known simply as the Congress Avenue Bridge) crosses over Lady Bird Lake in Austin, Texas. Before construction of the Longhorn Dam was completed in 1960, the bridge crossed the Colorado ...

in Austin is the summer home for over half a million (they winter in Mexico) and is the largest bat colony anywhere in an urban area. The Edwards Plateau is home to at least 14 endemic freshwater fishes, including two subterranean species of catfish and 13 fish species considered to be spring-associated. Mechanisms for spring association of fishes is not fully understood, but thought to mediated by water temperature. The large numbers of reptiles and birds also include breeding populations of the Texan endemic

golden-cheeked warbler The golden-cheeked warbler (''Setophaga chrysoparia'') is an endangered species of bird that breeds in Central Texas, from Palo Pinto County southwestward along the eastern and southern edge of the Edwards Plateau to Kinney County. The golden-ch ...

(''Setophaga'' ''chrysoparia''). Much of the natural habitat of the plateau has been converted to residential development, especially around Austin and San Antonio in the eastern part of the plateau. Further alteration to the savanna has incurred through the encroachment of shrubs now that grassland fires are carefully controlled. Small areas of intact habitat remain in protected areas such as the

Balcones Canyonlands National Wildlife Refuge Balcones Canyonlands is a national wildlife refuge located in the Texas Hill Country to the northwest of Lago Vista, Texas. The refuge was formed in 1992 to conserve habitat for two endangered songbirds, the golden-cheeked warbler (''Setoph ...

and

Lost Maples State Natural Area Lost Maples State Natural Area is a area of hills and canyons on the upper Sabinal River in the Edwards Plateau Region of Texas. It is designated a ''Natural Area'', rather than a ''State Park'', which means the primary focus is the maintenan ...

. Another important area for wildlife is

Fort Cavazos Fort Cavazos is a United States Army post located near Killeen, Texas. The post is currently named after Gen. Richard E. Cavazos, a native Texan and the US Army’s first Hispanic four-star general. The post is located halfway between Austi ...

military base.

Human history

Earliest human settlement of this area was by

Native American Native Americans or Native American usually refers to Native Americans in the United States. Related terms and peoples include: Ethnic groups * Indigenous peoples of the Americas, the pre-Columbian peoples of North, South, and Central America ...

s. First it was used and wandered about by

Jumano The Jumanos were a tribe or several tribes, who inhabited a large area of western Texas, New Mexico, and northern Mexico, especially near the Junta de los Rios region with its large settled Indigenous population. They lived in the Big Bend area ...

and

Coahuiltecan The Coahuiltecan were various small, autonomous bands of Indigenous peoples of the Americas, Native Americans who inhabited the Rio Grande valley in what is now northeastern Mexico and southern Texas. The various Coahuiltecan groups were hunter ga ...

groups, then the Apacheria extended into the Southern Plains by the forerunners of the Lipan and

Mescalero Mescalero or Mescalero Apache () is an Apache tribe of Southern Athabaskan–speaking Native Americans. The tribe is federally recognized as the Mescalero Apache Tribe of the Mescalero Apache Reservation, located in south-central New Mexico. In ...

Apache The Apache ( ) are several Southern Athabaskan language-speaking peoples of the Southwestern United States, Southwest, the Southern Plains and Northern Mexico. They are linguistically related to the Navajo. They migrated from the Athabascan ho ...

s. After the expulsion of the Apachean groups from the Plains by the

Comanche The Comanche (), or Nʉmʉnʉʉ (, 'the people'), are a Tribe (Native American), Native American tribe from the Great Plains, Southern Plains of the present-day United States. Comanche people today belong to the List of federally recognized tri ...

, this area was dominated by the

Penateka The Comanche (), or Nʉmʉnʉʉ (, 'the people'), are a Native American tribe from the Southern Plains of the present-day United States. Comanche people today belong to the federally recognized Comanche Nation, headquartered in Lawton, Oklahoma ...

band of the Southern Comanche.

Counties in the Edwards Plateau

According to the

Texas Parks and Wildlife Department The Texas Parks & Wildlife Department (TPWD) is a Texas state agency that oversees and protects wildlife and their habitat (ecology), habitats. In addition, the agency is responsible for managing the state park, state's parks and historical ar ...

, all or portions of these 41 counties comprise the Edwards Plateau geographic region:Texas Parks and Wildlife http://www.tpwd.state.tx.us/huntwild/wild/birding/pif/assist/pif_regions/region_7.phtml The Texas Water Development Board, a state government agency, includes additional counties all or partly in the Edwards Plateau area: A map showing the counties is provided by

for the Edwards Plateau Ecoregion. The ecoregion is somewhat larger than the geographic region, as the map from Texas Parks And Wildlife includes additional counties that are listed by the Texas Water Development Board, notably the isolated area of Edwards Plateau in Taylor, Runnels, and Nolan Counties that is separated from the main region.

Edwards Plateau gallery

File:San Saba River near Sloan, San Saba County, Texas, USA (9 May 2014).jpg,

San Saba River The San Saba River is a river in Texas, United States. It is an undeveloped and scenic waterway located on the northern boundary of the Edwards Plateau. Course The river begins in two primary branches. The North Valley Prong runs east throu ...

near Sloan, San Saba County (9 May 2014) File:Wildflowers on ranchland, State Highway 965, Llano County, Texas, USA (13 April 2012).jpg, Wildflowers on ranchland, State Highway 965, Llano County (13 April 2012) File:Llano River seen from County Road 320, Kimble County, Texas, USA (17 April 2015).jpg,

Llano River The Llano River ( ) is a tributary of the Colorado River, about long, in Texas in the United States. It drains part of the Edwards Plateau in Texas Hill Country northwest of Austin. Two spring-fed tributaries, the North and South Llano, stret ...

from County Road 320, Kimble County (17 April 2015) File:Texas cooter (Pseudemys texana) and red-eared slider (Trachemys scripta), Colorado River, Travis County, Texas, USA (12 April 2012).jpg, Texas cooter ('' Pseudemys texana'') and red-eared slider (''

Trachemys scripta The pond slider (''Trachemys scripta'') is a species of common, medium-sized, semiaquatic turtle. Three subspecies are described, the most recognizable of which is the red-eared slider (''T. s. elegans''), which is popular in the pet trade and ha ...

''), Colorado River, Travis County (12 April 2012) File:The Guadalupe River in Kerr County, Texas, USA (8 May 2014).jpg, The Guadalupe River in Kerr County (8 May 2014) File:Ranchland with Texas bluebonnets (Lupinus texensis) in western Kerr County, Texas, USA (17 April 2015).jpg, Ranchland with Texas bluebonnets (''

Lupinus texensis ''Lupinus texensis'', the Texas bluebonnet or Texas lupine is a species of lupine found in Texas, Louisiana, Arkansas and the Mexican states of Coahuila, Nuevo León, and Tamaulipas. With other related species of lupines also called bluebonne ...

'') in western Kerr County (17 April 2015) File:Bald Cypress (Taxodium distichum) growing on the Guadalupe River, Kerr County, Texas, USA (14 April 2012).jpg, Bald cypress (''

Taxodium distichum ''Taxodium distichum'' (baldcypress, bald-cypress, bald cypress, swamp cypress; ; ''cipre'' in Louisiana) is a deciduous conifer in the family Cupressaceae. It is native to the southeastern United States. Hardy and tough, this tree adapts to a ...

'') growing on the Guadalupe River, Kerr County (14 April 2012) File:Ranchland in the Edwards Plateau, Mason County, Texas, USA (17 April 2015).jpg, Ranchland in the Edwards Plateau, Mason County (17 April 2015) File:Crevice spiny lizard (Sceloporus poinsettii), Mason County, Texas, USA (9 May 2014).jpg, Crevice spiny lizard ('' Sceloporus poinsettii''), Mason County, Texas, US (9 May 2014) File:Highway 187 in the Edwards Plateau, Bandera County, Texas, USA (14 April 2012).jpg, Highway 187 in the Edwards Plateau, Bandera County, Texas, US (14 April 2012) File:Limestone bluff, typical of the Edwards Plateau, Highway 336, Real County, Texas, USA (14 Apr 2012).jpg, Limestone bluff, typical of the Edwards Plateau, Highway 336, Real County (14 Apr 2012) File:Ranchland seen from Highway 336, Real County, Texas, USA (14 April 2012).jpg, Ranchland seen from Highway 336, Real County (14 April 2012) File:Scarlet Penstemon (Penstemon triflorus), endemic to Edwards Plateau, Edwards County, Texas, USA (18 April 2015).jpg, Scarlet penstemon (''

Penstemon triflorus ''Penstemon triflorus'', Heller's beardtongue or Heller's penstemon, is a penstemon notable for its showy, purple blossoms. Distribution and habitat Heller's beardtongue grows on the Edwards Plateau of Texas. triflorus Flora of Texas

''), endemic to the Edwards Plateau, Edwards County (18 April 2015) File:Ranch road in southern Edwards County, Texas, USA (18 April 2015).jpg, Ranch road in southern Edwards County (18 April 2015). File:Cedar Creek, Edwards County, Texas, USA (18 April 2015).jpg, Cedar Creek, Edwards County (18 April 2015)

References

External links

* *
Texas counties map showing the ecoregion
{{Coord, 30.3, -99.6, display=title Landforms of Texas Plateaus of the United States Regions of Texas Tropical and subtropical grasslands, savannas, and shrublands of the United States Ecoregions of the United States Geography of Texas Grasslands of Texas Texas Hill Country Physiographic sections