South Texas Plains. Texas, Our Texas

South Texas Plains This is a region characterized by considerable variety. Climatically, the South Texas Plains region is sub-humid to dry. The in the north part of the South Texas, erosion of the Edwards Plateau can be seen in the soil. The area is characterized by black soils that extend from Austin to San Antonio and thence westward, although discontinuously, to Uvalde. Those areas having typical black-earth soils are highly important for farming purposes. Areas closer to the coastal region have layers of sand that are stabilized by grasses, shrubs, and mesquite trees. Farther south, lower Rio Grande country, consisting of a smooth to very slightly rolling upland of black-earth soils and the lowland of the Rio Grande River, including its delta area. The area is home to native grasses and shrubs that survive in the semi-dry climate. Hunting is popular in this area due the large herds of deer that graze on the grasses and shrubs. South Texas Plains has more biodiversity than any other ecoregion in Texas. Hundreds of species of birds live in the South Texas Plains. The Rio Grande Valley in the southern portion of the South Texas Plains is home to many subtropical species of animals due to its humid climate.

Post Oak Savannah The original savannahs in the northern part of the Oak-Prairie region were characterized by native grasses such as little bluestem, silver bluestem, and brownseed paspalum with scattered clumps of trees. Post oak trees dominated, but other species included blackjack oak, water oak, winged elm, hackberry, and yaupon. The most striking change to the savannah has been the loss of the native range grasses from overgrazing and the clearing of the native range to plant other grasses, such as coastal Bermuda grass, for cattle. The rich diversity of grasses and weeds in the native savannah provided food and cover for many wildlife species and the planning of the new grasses is responsible for the decline and even disappearance of species such as the bobwhite quail in much of the area. The Coyote is an extremely intelligent animal with keen senses of hearing, sight and smell. Coyotes will eat just about anything. They feed primarily on rabbits, rodents and insects, but they also eat lizards, snakes, fruit, vegetable matter and even fish. This adaptability also is evident in their use of cover. The Coyote requires minimal shelter to survive, but it will use a den for the birth and care of its young. The terrain is nearly level to gently rolling with elevations. The Post Oak Savannah landscape was formed and maintained by two major forces: frequent fire and grazing of bison. Recurrent fires ignited either by lightning or humans (American Indian) were the major force that molded the prairie and savannah landscapes.

Cross Timbers The terrain in most of this region is very hilly, with sandstone and limestone escarpments, steep slopes, and irregular surface features. Watersheds of the Red, Colorado, Trinity and Brazos Rivers cross the region from northwest to southeast. Exposed sandstone rocks and boulders dominate landscape features in many areas. The cross timbers region provides habitats for white-tailed deer, Rio Grande turkey, bobwhite quail, fox squirrels, and rabbits. Post oak-blackjack oak woodlands characterize much of the cross timbers region. Other associated woody species include Spanish oak, live oak, Texas ash, mesquite, Ashe juniper, cedar elm, skunk bush, rough-leafed dogwood, flame-leaf sumac, hawthorn, and hackberry.

RM 7 The Piney Woods Big Thicket Pine Palmetto Leaf Many parts of this ecoregion are characterized by longleaf pine forests on rolling sandy uplands. A variety of broad-leaved plants, shrubs, and grasses grow in this ecoregion of Texas. Photos: National Park Service Bald Cypress Marsh Neches River The Big Thicket national preserve is part of the Piney Woods. There are over 85 species of trees, 1,000 flowering plants, and over 180 kinds of birds in the Big Thicket. Photos: National Park Service 2010 TEXAS EDUCATION AGENCY. ALL RIGHTS RESERVED. 235

RM 7 continued Gulf Coast Plains and Marshes Barrier Island Barrier islands, peninsulas, marshes, and flat plains characterize this ecoregion. Sixty percent of the Texas Gulf Coast shoreline erodes from 30 cm to 15 m per year. Photo: U.S. Army Corps of Engineers Rosette Spoonbills Whooping Cranes The western part of the Gulf Coast Plain is one of the most biologically diverse regions of Texas. Nearly 500 species of resident and migratory birds have been recorded in the Texas coastal region. Photo: U.S. Army Corps of Engineers 2010 TEXAS EDUCATION AGENCY. ALL RIGHTS RESERVED. 237

RM 7 continued Edwards Plateau/Llano Uplift Enchanted Rock Canyonlands The Llano Uplift is located within the Edwards Plateau ecoregion. It is sometimes referred to as the Hill Country. Domelike rock formations of exposed pink granite are located in this region. Unique plant communities are often found on these domes. An example of this type of rock formation is the Enchanted Rock.The southeast portion of the Edwards Plateau is an area of canyonlands. A diversity of plants can be observed in this area, including deciduous forests, grasses, mesquite trees, and wildflowers. Photos: Texas Parks and Wildlife Mexican Free-Tailed Bats Texas Blind Salamander Mexican free-tailed bats, the Texas blind salamander, and the golden-cheeked warbler are just a few of the unique animals that can be observed in the region. Cool, clear springs and streams provide water for the vegetation and wildlife. Photos: Texas Parks and Wildlife 2010 TEXAS EDUCATION AGENCY. ALL RIGHTS RESERVED. 239

Texas, Our Texas RM 7 continued High Plains Playa Prairie Dog This ecoregion usually receives less than 20 inches of precipitation per year. Seasonal lakes called playas are found in this ecoregion. These lakes are filled with salts due to the erosion of nearby hills by rainwater. Playas are key sites of biodiversity. They provide important habitats for ducks, geese, sand hill cranes, shorebirds, amphibians, and small mammals. Photo: Loren M. Smith, Texas Tech University Palo Duro Canyon The Palo Duro Canyon is the second largest canyon in the United States. It was formed by water erosion of the Prairie Dog Town Fork of the Red River. 2010 TEXAS EDUCATION AGENCY. ALL RIGHTS RESERVED. 241

RM 7 continued Trans Pecos/Chihuahuan Desert Croton Peak Roadrunner The area generally west of the Pecos River in Texas is often called the Trans-Pecos. It occupies the northern part of the Chihuahuan Desert, which extends south nearly 500 miles into Mexico. Shown here is Croton Peak in the northern part of Big Bend National Park. Roadrunners are well-adapted to desert habitats of the Southwest. They eat insects, spiders, snails, lizards, and some fruits and seeds. Blooming Cactus Grasslands The Trans Pecos ecoregion has diverse topography. It includes desert flats and valleys, plateaus, sand hills, and mountain ranges. Grasslands, shrub lands, cactus savannas, and mountain woodlands also occur. Photo: Michel Farhi 2010 TEXAS EDUCATION AGENCY. ALL RIGHTS RESERVED. 243