Edwards Plateau
Encyclopedia
The Edwards Plateau is a region of west-central Texas
which is bounded by the Balcones Fault
to the south and east, the Llano Uplift
and the Llano Estacado
to the north, and the Pecos River
and Chihuahuan Desert
to the west. San Angelo
, Austin
, San Antonio and Del Rio
roughly outline the area. The eastern portion of the plateau is the Texas Hill Country
.
, the following 40 counties comprise the Edwards Plateau:
, with elevations ranging between 100 ft. and 3000 ft. Caves are numerous.
The landscape of the Plateau is mostly savanna
scattered with trees. The Plateau mostly lacks deep soil suitable for farming, though the soil is fertile mollisols
and some cotton, grain sorghum and oats are grown. However for the most part the thin soil and rough terrain areas are primarily grazing
regions, with cattle, sheep and Angora goat
s predominant. Several rivers cross the region, which generally flow to the south and east through the Texas Hill Country
toward the Gulf of Mexico
; springs occur (in wet years), however 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
recharge zone at the south of the plateau to feed rivers to the south. Rainfall varies from 15 to 33 in. per year, on average, from northwest to southeast, the area has a moderate temperature and a reasonably long growing season.
Flora
Trees of the savanna include a juniper
-oak
mix and a mesquite
-acacia
mix scattered over fairly short grasses, which traditionally were affected by droughts and regular fires. There are some maple
trees near to springs and rivers. The Balcones Fault
is associated with the Edwards Plateau formation. This fault line is an ecological demarcation for the range definition of a number of species. For example, the California Fan Palm, Washingtonia filifera
, is known to occur only west of the Edwards Plateau or Balcones Fault, and Buddleja racemosa
is known only from the southern edge of the plateau.
Fauna
Caves of the Edwards Plateau are important habitat for a great deal of wildlife. The area is home to some of the largest colonies of bats in the world, including millions of Mexican free-tailed bat
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. There are also large numbers of reptiles and birds including breeding populations of the Texan endemic Golden-cheeked Warbler
(Dendroica chrysoparia).
Nearly all the natural habitat of the plateau has been converted to farmland or urban areas such as Austin and San Antonio, with only about 2% remaining in scattered fragments, especially to the east of the plateau. Further alteration to the savanna has incurred though the encroachment of shrubs now that grassland fires are carefully controlled. Small areas of intact habitat remain, particularly around Austin where there are protected areas such as the Balcones Canyonlands National Wildlife Refuge
. Another important area for wildlife is Fort Hood military base.
s.
First it was used and wandered about by Jumano and Coahuiltecan
groups, than after the Apacheria extends into the Southern Plains by the forerunners of the Lipan and Mescalero
Apache
s. After the expulsion of the Apachean groups from the Plains by the Comanche
, this area was dominated by the Penateka band of the Southern Comanche.
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
which is bounded by the Balcones Fault
Balcones Fault
The Balcones Fault Zone is a tensional structural system in Texas that runs approximately from the southwest part of the state near Del Rio to the north central region near Waco along Interstate 35. The Balcones Fault zone is made up of many smaller features, including normal faults, grabens, and...
to the south and east, the Llano Uplift
Llano Uplift
The Llano Uplift is a roughly circular geologic dome of Precambrian rock, primarily granite, in Central Texas in the United States. It is located in the eastern region of the Edwards Plateau, west of the Texas Hill Country...
and the Llano Estacado
Llano Estacado
Llano Estacado , commonly known as the Staked Plains, is a region in the Southwestern United States that encompasses parts of eastern New Mexico and northwestern Texas, including the South Plains and parts of the Texas Panhandle...
to the north, and the Pecos River
Pecos River
The headwaters of the Pecos River are located north of Pecos, New Mexico, United States, at an elevation of over 12,000 feet on the western slope of the Sangre de Cristo mountain range in Mora County. The river flows for through the eastern portion of that state and neighboring Texas before it...
and Chihuahuan Desert
Chihuahuan Desert
The Chihuahuan Desert is a desert, and an ecoregion designation, that straddles the U.S.-Mexico border in the central and northern portions of the Mexican Plateau, bordered on the west by the extensive Sierra Madre Occidental range, and overlaying northern portions of the east range, the Sierra...
to the west. San Angelo
San Angelo, Texas
San Angelo is a city in the state of Texas. Located in West Central Texas it is the county seat of Tom Green County. As of 2010 according to the United States Census Bureau, the city had a total population of 93,200...
, Austin
Austin, Texas
Austin is the capital city of the U.S. state of :Texas and the seat of Travis County. Located in Central Texas on the eastern edge of the American Southwest, it is the fourth-largest city in Texas and the 14th most populous city in the United States. It was the third-fastest-growing large city in...
, San Antonio and Del Rio
Del Rio, Texas
Del Rio is a border city in and the county seat of Val Verde County, Texas, United States.. Del Rio is connected with Ciudad Acuña via the Lake Amistad Dam International Crossing and Del Río-Ciudad Acuña International Bridge...
roughly outline the area. The eastern portion of the plateau is the Texas Hill Country
Texas Hill Country
The Texas Hill Country is a vernacular term applied to a region of Central Texas featuring tall rugged hills consisting of thin layers of soil atop limestone or granite. It also includes the Llano Uplift and the second largest granite monadnock in the United States, Enchanted Rock, which is located...
.
Counties in the Edwards Plateau
According to the Texas Parks and Wildlife DepartmentTexas Parks and Wildlife Department
The Texas Parks & Wildlife Department is a Texas state agency that oversees and protects wildlife and their habitats. In addition, the agency is responsible for managing the state's parks and historical areas...
, the following 40 counties comprise the Edwards Plateau:
|
Erath County, Texas Erath County is a county located on the Edwards Plateau in the U.S. state of Texas. In 2000, its population was 33,001. It is named for George Bernard Erath, an early surveyor and a soldier at the Battle of San Jacinto. The seat of the county is Stephenville.... Gillespie County, Texas Gillespie County is a county located on the Edwards Plateau in the U.S. state of Texas. In 2010, its population was 24,837. It is located in the heart of the Texas Hill Country. Gillespie is named for Robert Addison Gillespie, who came to Texas in 1837. He was a Texas Ranger, an Indian fighter, a... Hays County, Texas Hays County is a county located on the Edwards Plateau in the U.S. state of Texas. In 2010, its official population had reached 157,107. It is named for John Coffee Hays, a Texas Ranger and Mexican-American War officer. The seat of the county is San Marcos.... Kendall County, Texas Kendall County is a county located on the Edwards Plateau in the U.S. state of Texas. In 2008 census, its population was 32,886. Its seat is Boerne.... Kerr County, Texas Kerr County is a county located on the Edwards Plateau in the U.S. state of Texas. In 2010, its population was 49,625. Its county seat is Kerrville. Kerr County was named by Joshua D. Brown for his fellow Kentucky native, James Kerr, a congressman of the Republic of Texas... Kimble County, Texas Kimble County is a county located on the Edwards Plateau in the U.S. state of Texas. In 2000, its population was 4,468. Its county seat is Junction. Kimble is named for George C. Kimble, who died at the Battle of the Alamo.-Geography:... |
Lampasas County, Texas Lampasas County is a county located on the Edwards Plateau in the U.S. state of Texas. In 2000, its population was 17,762. Its seat is Lampasas. The county is named for the Lampasas River.... Llano County, Texas Llano County is a county located on the Edwards Plateau in the U.S. state of Texas. In 2010, its population was 19, 301. Its county seat is Llano, and the county is named for the Llano River.... Mason County, Texas Mason County is a county located on the Edwards Plateau in the U.S. state of Texas. In 2010, its population was 4, 012. Its county seat is Mason... McCulloch County, Texas McCulloch County is a county located on the Edwards Plateau in the U.S. state of Texas. The geographical center of Texas lies within the county. In 2000, its population was 8,205. Its county seat is Brady. McCulloch is named for Benjamin McCulloch, a famous Texas Ranger and Confederate... McLennan County, Texas McLennan County is a county located on the Edwards Plateau in Central Texas. In 2000, its population was 213,517; in 2008 the U.S. Census Bureau estimated its population to be 230,213. Its seat is Waco. The county is named for Neil McLennan, an early settler.... Mills County, Texas Mills County is a county located on the Edwards Plateau in Central Texas. In 2000, its population was 5,151. Mills County is named for John T. Mills, a justice of the Texas Supreme Court... Palo Pinto County, Texas As of the census of 2000, there were 27,026 people, 10,594 households, and 7,447 families residing in the county. The population density was 28 people per square mile . There were 14,102 housing units at an average density of 15 per square mile... Reagan County, Texas Reagan County is a county located on the Edwards Plateau in the U.S. state of Texas. In 2000, its population was 3,326. The seat of the county is Big Lake. It is named in honor of John Henninger Reagan , who served as postmaster general of the Confederate States of America and also as a U.S.... |
San Saba County, Texas San Saba County is a county located on the Edwards Plateau in Western Central Texas. In 2010, its population was 6,131. Its county seat is San Saba. It is named for the San Saba River, which flows through the county.-History:... Somervell County, Texas There were 2,438 households out of which 37.40% had children under the age of 18 living with them, 61.70% were married couples living together, 9.60% had a female householder with no husband present, and 24.50% were non-families. 21.30% of all households were made up of individuals and 9.20% had... Sterling County, Texas Sterling County is a county located on the Edwards Plateau in the U.S. state of Texas. In 2000, its population was 1,393. Its county seat is Sterling City. The county is named for W. S. Sterling, an early settler in the area. Sterling County is one of 30 prohibition, or entirely dry, counties in... Travis County, Texas As of 2009, the U.S. census estimates there were 1,026,158 people, 320,766 households, and 183,798 families residing in the county. The population density was 821 people per square mile . There were 335,881 housing units at an average density of 340 per square mile... Upton County, Texas Upton County is a county located on the Edwards Plateau in the U.S. state of Texas. In 2000, its population was 3,404. Its county seat is Rankin. The county is named for two brothers: John C. and William F. Upton, both Colonels in the Confederate army.... Val Verde County, Texas Val Verde County is a county located on the Edwards Plateau in the U.S. state of Texas. In 2008, estimated population was 55,000. Its county seat is Del Rio. In 1936, Val Verde County received Recorded Texas Historic Landmark number 5625 to commemorate its founding.Val Verde, which means "green... Williamson County, Texas Williamson County is a county located on both the Edwards Plateau to the west, consisting of rocky terrain and hills, and Blackland Prairies in the east consising of rich, fertile farming land, The two areas are roughly bisected by Interstate 35... |
Natural history
The bedrock consists primarily of limestoneLimestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
, with elevations ranging between 100 ft. and 3000 ft. Caves are numerous.
The landscape of the Plateau is mostly savanna
Savanna
A savanna, or savannah, is a grassland ecosystem characterized by the trees being sufficiently small or widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of C4 grasses.Some...
scattered with trees. The Plateau mostly lacks deep soil suitable for farming, though the soil is fertile mollisols
Mollisols
Mollisols are a soil order in USDA soil taxonomy. Mollisols form in semi-arid to semi-humid areas, typically under a grassland cover. They are most commonly found in the mid-latitudes, namely in North America, mostly east of the Rocky Mountains, in South America in Argentina and Brazil, and in...
and some cotton, grain sorghum and oats are grown. However for the most part the thin soil and rough terrain areas are primarily grazing
Grazing
Grazing generally describes a type of feeding, in which a herbivore feeds on plants , and also on other multicellular autotrophs...
regions, with cattle, sheep and Angora goat
Angora goat
The Angora goat is a breed of domestic goat that originated in Ankara , Turkey and its surrounding region in central Anatolia...
s predominant. Several rivers cross the region, which generally flow to the south and east through the Texas Hill Country
Texas Hill Country
The Texas Hill Country is a vernacular term applied to a region of Central Texas featuring tall rugged hills consisting of thin layers of soil atop limestone or granite. It also includes the Llano Uplift and the second largest granite monadnock in the United States, Enchanted Rock, which is located...
toward the Gulf of Mexico
Gulf of Mexico
The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...
; springs occur (in wet years), however 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
Edwards Aquifer
The Edwards Aquifer is one of the most prolific artesian aquifers in the world. Located on the eastern edge of Edwards Plateau in the U.S. state of Texas, it discharges about of water a year and directly serves about two million people...
recharge zone at the south of the plateau to feed rivers to the south. Rainfall varies from 15 to 33 in. per year, on average, from northwest to southeast, the area has a moderate temperature and a reasonably long growing season.
Flora
Trees of the savanna include a juniper
Juniper
Junipers are coniferous plants in the genus Juniperus of the cypress family Cupressaceae. Depending on taxonomic viewpoint, there are between 50-67 species of juniper, widely distributed throughout the northern hemisphere, from the Arctic, south to tropical Africa in the Old World, and to the...
-oak
Oak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...
mix and a mesquite
Mesquite
Mesquite is a leguminous plant of the Prosopis genus found in northern Mexico through the Sonoran Desert and Chihuahuan Deserts, and up into the Southwestern United States as far north as southern Kansas, west to the Colorado Desert in California,and east to the eastern fifth of Texas, where...
-acacia
Acacia
Acacia is a genus of shrubs and trees belonging to the subfamily Mimosoideae of the family Fabaceae, first described in Africa by the Swedish botanist Carl Linnaeus in 1773. Many non-Australian species tend to be thorny, whereas the majority of Australian acacias are not...
mix scattered over fairly short grasses, which traditionally were affected by droughts and regular fires. There are some maple
Maple
Acer is a genus of trees or shrubs commonly known as maple.Maples are variously classified in a family of their own, the Aceraceae, or together with the Hippocastanaceae included in the family Sapindaceae. Modern classifications, including the Angiosperm Phylogeny Group system, favour inclusion in...
trees near to springs and rivers. The Balcones Fault
Balcones Fault
The Balcones Fault Zone is a tensional structural system in Texas that runs approximately from the southwest part of the state near Del Rio to the north central region near Waco along Interstate 35. The Balcones Fault zone is made up of many smaller features, including normal faults, grabens, and...
is associated with the Edwards Plateau formation. This fault line is an ecological demarcation for the range definition of a number of species. For example, the California Fan Palm, Washingtonia filifera
Washingtonia filifera
Washingtonia filifera , with the common names California Fan Palm , Desert Fan Palm, Cotton palm, and Arizona Fan Palm. It is a palm native to southwestern North America between an elevation range of , at seeps, desert bajadas, and springs where underground water is continuously available...
, is known to occur only west of the Edwards Plateau or Balcones Fault, and Buddleja racemosa
Buddleja racemosa
Buddleja racemosa, commonly known as the Wand Butterfly Bush, is endemic to the southern edge of the limestone Edwards Plateau in Texas, USA, from Austin to Rocksprings, growing around streams, creeks and springs at elevations of 250 -750 m. The plant was first named and described by John...
is known only from the southern edge of the plateau.
Fauna
Caves of the Edwards Plateau are important habitat for a great deal of wildlife. The area is home to some of the largest colonies of bats in the world, including millions of Mexican free-tailed bat
Mexican Free-tailed Bat
The Mexican free-tailed bat , also known as the Brazilian free-tailed bat, is a medium-sized bat that is native to the Americas and is widely regarded as one of the most abundant mammals in North America...
s. The largest colony of these inhabits Bracken Cave
Bracken Cave
Bracken Cave is the largest known habitat for Mexican Free-tailed Bats. It is located in southern Comal County, Texas, outside the city of San Antonio. Bracken Cave houses a colony of over 20 million bats, making it the largest known concentration of mammals, except for humans...
near San Antonio, while the Congress Avenue Bridge
Ann W. Richards Congress Avenue Bridge
The Ann W. Richards Congress Avenue Bridge crosses over Lady Bird Lake in Austin, Texas. Before the construction of Longhorn Dam was completed in 1960, the bridge crossed the Colorado River from which Lady Bird Lake is impounded...
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. There are also large numbers of reptiles and birds including breeding populations of the Texan endemic Golden-cheeked Warbler
Golden-cheeked Warbler
The Golden-cheeked Warbler Dendroica 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...
(Dendroica chrysoparia).
Nearly all the natural habitat of the plateau has been converted to farmland or urban areas such as Austin and San Antonio, with only about 2% remaining in scattered fragments, especially to the east of the plateau. Further alteration to the savanna has incurred though the encroachment of shrubs now that grassland fires are carefully controlled. Small areas of intact habitat remain, particularly around Austin where there are protected areas such as the Balcones Canyonlands National Wildlife Refuge
Balcones Canyonlands National Wildlife Refuge
Balcones Canyonlands is a National Wildlife Refuge located in the Texas Hill Country to the northwest of Austin, Texas. The Refuge was formed in 1992 to conserve habitat for two endangered songbirds including the Golden-cheeked Warbler and the Black-capped Vireo and to preserve Texas Hill Country...
. Another important area for wildlife is Fort Hood military base.
Human history
Earliest human settlement of this are was by Native AmericanIndigenous peoples of the Americas
The indigenous peoples of the Americas are the pre-Columbian inhabitants of North and South America, their descendants and other ethnic groups who are identified with those peoples. Indigenous peoples are known in Canada as Aboriginal peoples, and in the United States as Native Americans...
s.
First it was used and wandered about by Jumano and Coahuiltecan
Coahuiltecan
Coahuiltecan or Paikawa was a proposed language family in John Wesley Powell's 1891 classification of Native American languages that consisted of Coahuilteco and Cotoname. The proposal was expanded to include Comecrudo, Karankawa, and Tonkawa...
groups, than after the Apacheria extends into the Southern Plains by the forerunners of the Lipan and Mescalero
Mescalero
Mescalero is an Apache tribe of Southern Athabaskan Native Americans. The tribe is federally recognized as the Mescalero Apache Tribe of the Mescalero Apache Reservation in southcentral New Mexico...
Apache
Apache
Apache is the collective term for several culturally related groups of Native Americans in the United States originally from the Southwest United States. These indigenous peoples of North America speak a Southern Athabaskan language, which is related linguistically to the languages of Athabaskan...
s. After the expulsion of the Apachean groups from the Plains by the Comanche
Comanche
The Comanche are a Native American ethnic group whose historic range consisted of present-day eastern New Mexico, southern Colorado, northeastern Arizona, southern Kansas, all of Oklahoma, and most of northwest Texas. Historically, the Comanches were hunter-gatherers, with a typical Plains Indian...
, this area was dominated by the Penateka band of the Southern Comanche.
See also
- Texas Hill CountryTexas Hill CountryThe Texas Hill Country is a vernacular term applied to a region of Central Texas featuring tall rugged hills consisting of thin layers of soil atop limestone or granite. It also includes the Llano Uplift and the second largest granite monadnock in the United States, Enchanted Rock, which is located...
- Balcones Canyonlands National Wildlife RefugeBalcones Canyonlands National Wildlife RefugeBalcones Canyonlands is a National Wildlife Refuge located in the Texas Hill Country to the northwest of Austin, Texas. The Refuge was formed in 1992 to conserve habitat for two endangered songbirds including the Golden-cheeked Warbler and the Black-capped Vireo and to preserve Texas Hill Country...
- Colorado River (Texas)Colorado River (Texas)The Colorado River is a river that runs through the U.S. state of Texas; it should not be confused with the much longer Colorado River which flows from Colorado into the Gulf of California....
- Mount BonnellMount BonnellMount Bonnell , also known as Covert Park, is a prominent point alongside Lake Austin portion of the Colorado River in Austin, Texas. It has been a popular tourist destination since the 1850s. The mount provides a vista for viewing the city of Austin, Lake Austin, and the surrounding hills...