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. It is bounded by the Balcones Fault to the south and east; the Llano Uplift 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,

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, 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 junipers (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 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 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 near San Antonio, while the Congress Avenue Bridge 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 (''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. 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 Americans. First it was used and wandered about by Jumano 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 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 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 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''), 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'') 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